CN117713508A - Power converter and control method thereof - Google Patents
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Abstract
The present disclosure relates to the field of power electronics, and in particular, to a power converter and a control method thereof. The power converter includes: the power conversion circuit comprises at least one pair of switching tubes, wherein the first end of one switching tube in each pair of switching tubes is connected with the second end of the other switching tube; the control circuit is connected with the power conversion circuit and used for controlling the power conversion circuit, after one switching tube of the pair of switching tubes is turned off, an integral charge value representing the total charge change amount of the pair of switching tubes is obtained, and when the integral charge value reaches a corresponding charge threshold value, the other switching tube of the pair of switching tubes is controlled to be turned on. The zero-voltage switching-on of the switching tube is realized, the conduction loss of a parasitic diode of the switching tube is avoided, and the conversion efficiency of the power converter is improved.
Description
Technical Field
The present disclosure relates to the field of power electronics, and in particular, to a power converter and a control method thereof.
Background
In a half-bridge or bridge converter, a conduction dead zone is generally provided to prevent the bridge arm from being directly connected, and in the dead zone time of the bridge arm commutation process, there is a process of commutating from the original on switching device to the parasitic diode of the complementary tube.
If the dead time is too short, zero voltage turn-on cannot be realized, and extra turn-on loss is generated. If the dead time is set too long, the parasitic diode freewheel time increases, and the parasitic diodes of the switching devices such as MOS transistors, siC transistors, and GaN transistors generally have a large conduction voltage drop, resulting in a large increase in the conduction loss of the switching devices. In practical application, for working conditions of different currents and different bus voltages, the time for converting current from the original on switching device to the parasitic diode of the complementary tube in dead time is also different. Therefore, in order to realize zero voltage turn-on under all working conditions, when the dead time is set, the related technology tends to set a larger fixed value, so that the dead time is too long under most working conditions, and the conduction loss of the parasitic diode of the switching device is increased.
Disclosure of Invention
In view of the foregoing, it is desirable to provide a power converter and a control method thereof.
In a first aspect, an embodiment of the present invention proposes a power converter, the power converter comprising:
the power conversion circuit comprises at least one pair of switching tubes, wherein the first end of one switching tube in each pair of switching tubes is connected with the second end of the other switching tube;
The control circuit is connected with the power conversion circuit and used for controlling the power conversion circuit, after one switching tube of the pair of switching tubes is turned off, an integral charge value representing the total charge change amount of the pair of switching tubes is obtained, and when the integral charge value reaches a corresponding charge threshold value, the other switching tube of the pair of switching tubes is controlled to be turned on.
In one embodiment, the control circuit includes:
the sampling circuit is used for sampling the electric signals of the pair of switching tubes to obtain sampling signals;
the integration module is connected with the sampling circuit and used for integrating the sampling signal to obtain the integrated charge value;
the controller is connected with the integration module and comprises a control module, the control module provides a dead zone signal for controlling the integration module and a control signal for controlling at least one pair of switching tubes, when one switching tube in the pair of switching tubes is turned off, the dead zone signal controls the integration module to start integrating the sampling signal, and when the integrated charge value reaches a charge threshold value, the control signal controls the other switching tube in the pair of switching tubes to be turned on.
In an embodiment, the electrical signal is a current signal representative of the magnitude of current flowing out and in at the junction of the pair of switching tubes.
In an embodiment, the control circuit further comprises:
the detection module is used for detecting the turn-off time of the switching tube and providing detection signals to the control module;
and the comparison module is used for comparing the integrated charge value with the charge threshold value and outputting a comparison result to the control module.
In an embodiment, the control circuit further comprises:
and the rectification circuit is connected between the sampling circuit and the integration module and is used for rectifying the sampling signal and outputting the sampling signal to the integration module, and the integration module integrates the rectified sampling signal to obtain the integrated charge value.
In an embodiment, the control circuit further comprises:
the rectification selection circuit is connected between the sampling circuit and the integration module, rectifies the sampling signal, selectively outputs the rectified sampling signal with a first polarity corresponding to the current flowing out of the connection point or the rectified sampling signal with a second polarity corresponding to the current flowing in of the connection point according to the selection signal provided by the controller, and integrates the rectified sampling signal with the first polarity and the rectified sampling signal with the second polarity to obtain the integrated charge value.
In an embodiment, when the voltages at two ends of the pair of switching tubes are direct-current voltages, the switching tube at the high side in the pair of switching tubes is turned off, and the selection signal controls the output of the rectifying selection circuit to be switched into the rectified sampling signal with the first polarity; and/or
And at the switching-off moment of a switching tube positioned at the low side of the pair of switching tubes, the selection signal controls the output of the rectification selection circuit to be switched into a rectified sampling signal with the second polarity.
In an embodiment, under the condition that voltages at two ends of a pair of switching tubes are alternating voltages, in a power frequency positive half period, the switching-off moment of a high-side switching tube is positioned in the pair of switching tubes, and the selection signal controls the output of the rectification selection circuit to be switched into a sampling signal with a first polarity after rectification;
and the switching-off time of the low-side switching tube is positioned in the pair of switching tubes, and the selection signal controls the output of the rectification selection circuit to be switched into the rectified sampling signal with the second polarity.
In one embodiment, the rectification selection circuit includes:
the separation unit is used for separating the positive polarity and the negative polarity of the sampling signals output by the sampling circuit to obtain sampling signals of a first polarity corresponding to the current flowing out of the connection point and sampling signals of a second polarity corresponding to the current flowing in of the connection point;
The rectification unit is used for rectifying the sampling signal of the first polarity and the sampling signal of the second polarity respectively;
and the selection unit is used for selectively outputting the rectified sampling signal of the first polarity or the rectified sampling signal of the second polarity according to the selection signal.
In one embodiment, the power conversion circuit includes:
an inverter circuit for inverting the direct current into alternating current;
the resonant circuit is connected with the inverter circuit;
the frequency conversion circuit is connected with the resonant circuit and comprises two pairs of switching tubes which are connected in opposite directions and used for performing alternating current and alternating current conversion;
after one switching tube of a pair of switching tubes in the cycle conversion circuit is turned off, the integration module obtains a first integrated charge value representing the total charge change amount of the switching tubes, and when the first integrated charge value reaches a first charge threshold value, the control module controls the other switching tube of the switching tubes to be turned on.
In an embodiment, in a positive power frequency half period of the output voltage of the frequency conversion circuit, at a switching tube turn-off time of a switching tube located at a high side in a pair of switching tubes of the two pairs of switching tubes, the integrating module starts integrating the rectified sampling signal corresponding to the current flowing out of the connection point of the pair of switching tubes; the integration module starts integrating the rectified sampling signal corresponding to the current flowing into the connection point of the pair of switching tubes at the switching-off moment of the switching tube positioned at the low side of the pair of switching tubes;
In the power frequency negative half period of the output voltage of the frequency conversion circuit, the integration module starts integrating the rectified sampling signal corresponding to the current flowing into the connection point of the pair of switching tubes at the switching-off moment of the switching tube positioned at the high side in the other pair of switching tubes; at the switching-off time of the switching tube positioned at the lower side of the pair of switching tubes, the integrating module starts to integrate the rectified sampling signal corresponding to the current flowing out of the connecting point of the pair of switching tubes.
In one embodiment, when the integrated charge value reaches a corresponding charge threshold, the control module controls the integration module to discharge until the integrated charge value drops to 0.
In an embodiment, the inverter circuit includes at least one pair of switching tubes, and the integration module obtains a second integrated charge value representing a total amount of charge change of one of the pair of switching tubes after the switching tube of the pair of switching tubes in the inverter circuit is turned off, and when the second integrated charge value reaches a second charge threshold value, the control module controls the other switching tube of the pair of switching tubes to be turned on.
In one embodiment, the integration module comprises:
The first integration circuit is used for integrating the rectified sampling signal according to a first dead zone signal to obtain a first integrated charge value, and the first dead zone signal is generated by the control module according to the turn-off time of a switching tube in the frequency conversion circuit and a comparison result of the first integrated charge value and the first charge threshold value;
and the second integration circuit is used for integrating the rectified sampling signal according to a second dead zone signal to obtain a second integrated charge value, and the second dead zone signal is generated by the control module according to the turn-off time of a switching tube in the inverter circuit and the comparison result of the second integrated charge value and the second charge threshold value.
In an embodiment, the power conversion circuit further includes a transformer connected between the inverter circuit and the frequency conversion circuit;
the first charge threshold is determined according to the output voltage of the frequency conversion circuit and/or the parasitic capacitance of a switching tube in the frequency conversion circuit and an external parallel capacitor;
the second charge threshold is determined according to an input voltage of the inverter circuit, a turn ratio of the transformer, and/or a parasitic capacitance of a switching tube in the inverter circuit and an external parallel capacitance.
In an embodiment, when a first integrated charge value reaches a first charge threshold, the control module controls the first integrating circuit to discharge until the first integrated charge value drops to 0;
when the second integrated charge value reaches a second charge threshold, the control module controls the second integration circuit to discharge until the second integrated charge value drops to 0.
In an embodiment, the power conversion circuit is one of a BUCK conversion circuit, a BOOST conversion circuit, an LLC conversion circuit, a dual active bridge conversion circuit, a cyclic conversion circuit, a half bridge circuit, and a full bridge circuit.
In an embodiment, the power converter is a DC-DC type power converter or a DC-AC type power converter or an AC-DC type converter.
In a second aspect, an embodiment of the present invention proposes a control method for a power converter, for a power converter according to the first aspect, the method comprising:
after one switching tube of a pair of switching tubes is turned off, obtaining an integral charge value representing the total charge change amount of the pair of switching tubes;
and when the integrated charge value reaches a corresponding charge threshold value, controlling the other switching tube of the pair of switching tubes to be turned on.
In one embodiment, sampling the electrical signals of a pair of switching tubes to obtain a sampling signal;
and integrating the sampling signal to obtain the integrated charge value.
In an embodiment, the electrical signal is a current signal representative of the magnitude of current flowing out and in at the junction of the pair of switching tubes.
In an embodiment, the method further comprises:
and detecting the turn-off time of the switching tube, and starting to integrate the sampling signal when detecting that one switching tube in the pair of switching tubes is turned off.
In an embodiment, the method further comprises:
and rectifying the sampling signal, and integrating the rectified sampling signal to obtain the integrated charge value.
In an embodiment, the method further comprises:
and rectifying the sampling signals, and selecting the rectified sampling signals corresponding to the current flowing out of the connecting point or the sampling signals corresponding to the current flowing in of the connecting point to integrate according to the voltage polarities at the two ends of the pair of switching tubes and the turn-off time of the switching tubes to obtain the integrated charge value.
In an embodiment, when the voltages at two ends of a pair of switching tubes are positive, integrating the sampling signals corresponding to the current flowing out of the connection points at the switching tube turn-off time of the switching tube positioned at the high side in the pair of switching tubes; and/or
And integrating a sampling signal corresponding to the current flowing in the connection point at the switching-off time of the switching tube positioned at the lower side of the pair of switching tubes.
In an embodiment, the method further comprises:
and when the integrated charge value reaches a corresponding charge threshold value, starting discharging until the integrated charge value is reduced to 0.
Compared with the related art, after one switching tube of the pair of switching tubes is turned off, an integral charge value representing the total charge change amount of the pair of switching tubes is obtained, and when the integral charge value reaches a charge threshold value, the other switching tube of the pair of switching tubes is controlled to be turned on. According to the technical scheme, zero-voltage switching on of the switching tube is realized, the conduction loss of a parasitic diode of the switching tube is avoided, and the conversion efficiency of the power converter is improved;
furthermore, the dead time self-adaptive control is realized, and the method can be suitable for different working conditions.
Drawings
FIG. 1 is a schematic diagram of a current converting process of a power converting circuit in the prior art;
FIG. 2 is a schematic diagram of waveforms and voltage waveforms of a control signal of a power conversion circuit according to the prior art;
fig. 3 is a schematic structural diagram of a power converter according to a first embodiment provided in the present application;
FIG. 4 is a schematic diagram of driving waveforms and voltage waveforms according to an embodiment of the present application;
Fig. 5 is a schematic structural diagram of a power converter according to a second embodiment provided in the present application;
fig. 6 is a schematic structural diagram of a power converter according to a third embodiment provided in the present application;
fig. 7 is a schematic structural diagram of a power converter according to a fourth embodiment provided in the present application;
FIG. 8 is a schematic diagram of a rectifying selection circuit according to an embodiment of the present disclosure;
fig. 9 is a schematic circuit diagram of a power converter according to a first exemplary embodiment provided herein;
FIG. 10 is a schematic diagram of waveforms associated with a power converter in a first exemplary embodiment provided herein;
fig. 11 is a schematic circuit diagram of a power converter according to a second exemplary embodiment provided herein;
fig. 12 is a schematic circuit diagram of a power conversion circuit according to a third exemplary embodiment provided herein;
fig. 13 is a schematic circuit diagram of a control circuit in a third exemplary embodiment provided herein;
FIG. 14 is a schematic diagram of waveforms associated with a power converter in a third exemplary embodiment provided herein;
FIG. 15 is a schematic diagram of waveforms associated with a power converter according to a fourth exemplary embodiment provided herein;
fig. 16 is a circuit configuration diagram of a control circuit in a fourth exemplary embodiment provided in the present application.
Fig. 17 is a flow chart of a control method of a power converter provided in the present application.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described and illustrated below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the present application. All other embodiments, which can be made by one of ordinary skill in the art without undue burden on the person of ordinary skill in the art based on the embodiments provided herein, are intended to be within the scope of the present application. Moreover, it should be appreciated that while such a development effort might be complex and lengthy, it would nevertheless be a routine undertaking of design, fabrication, or manufacture for those of ordinary skill having the benefit of this disclosure, and thus should not be construed as having the benefit of this disclosure.
Reference in the specification to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is to be expressly and implicitly understood by those of ordinary skill in the art that the embodiments described herein can be combined with other embodiments without conflict.
Unless defined otherwise, technical or scientific terms used herein should be given the ordinary meaning as understood by one of ordinary skill in the art to which this application belongs. Reference to "a," "an," "the," and similar terms herein do not denote a limitation of quantity, but rather denote the singular or plural. The terms "comprising," "including," "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, article, or apparatus that comprises a list of steps or modules (elements) is not limited to only those steps or elements but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus. The terms "connected," "coupled," and the like in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The term "plurality" as used herein means greater than or equal to two. "and/or" describes an association relationship of an association object, meaning that there may be three relationships, e.g., "a and/or B" may mean: a exists alone, A and B exist together, and B exists alone. The terms "first," "second," "third," and the like, as used herein, are merely distinguishing between similar objects and not representing a particular ordering of objects.
FIG. 1 is a schematic diagram of a prior art power conversion circuit including a capacitor C bus Connected to the capacitor C bus The complementary conduction switch tube Q1 and switch tube Q2 at two ends, and the intermediate connection point of the switch tube Q1 and the switch tube Q2 outputs current i L . The capacitor C1 and the capacitor C2 are parasitic capacitances of the switching transistor Q1 and the switching transistor Q2, respectively.
The waveform of the control signal of the corresponding switching transistor and the waveform of the voltage received by the switching transistor Q2 are shown in fig. 2. Wherein v is c2 Is the voltage at the drain and source ends of the switching tube Q2, vg1 is the control signal of the switching tube Q1, and Vg2 is the control signal of the switching tube Q2. After the control signal Vg1 changes from high level to low level, the control signal Vg2 continues to be kept at low level, and the capacitor C bus Voltage V on bus The parasitic capacitance C1 of the switching tube Q1 starts to charge, and the current i L Discharging the parasitic capacitance C2 of the switching tube Q2 as shown in FIG. 1 (b), corresponding to t of FIG. 2 0 ～t 1 A time period; when the voltage on the parasitic capacitance C1 rises to V bus After the voltage across the parasitic capacitor C2 drops to zero, the parasitic diode of the switching tube Q2 starts to turn on as shown in fig. 1 (C), corresponding to t of fig. 2 1 ～t 2 A time period; when the control signal Vg2 of the switching transistor Q2 becomes high level, the current of the switching transistor Q2 is changed from the parasitic diode to the channel as shown in fig. 1 (d), corresponding to t of fig. 2 2 After the moment. The entire commutation process ends.
Related art will t 0 ～t 2 The time period is set to be a fixed dead time, which cannot reduce the conduction loss of the parasitic diode to be close to zero under all working conditions, so that the increased loss can bring about the problem of reducing the conversion efficiency of the power converter.
In fig. 1 and 2, when the switching tube Q1 is turned off, the ideal commutation time of the switching tube is t 0 -t 1 At this stage, the parasitic capacitance C1 is charged and the parasitic capacitance C2 is discharged; when the switching tube Q2 is turned off, the ideal commutation time of the switching tube is t 3 -t 4 At this stage, the parasitic capacitance C1 is discharged, the parasitic capacitance C2 is charged, and the total amount of charge change on the parasitic capacitance C1 and the parasitic capacitance C2, that is, the total amount of charge change of the switching transistor Q1 and the switching transistor Q2 satisfies the following relationship:
wherein v is c1 V is the voltage across the drain and source of the switching tube Q1 c2 For the voltage of the two ends of the drain and source of the switch tube Q2, C 1 (v c1 ) The capacitance of the parasitic capacitor C1 is related to the voltage v across the drain and source of the switch tube Q1 c1 Function C of (2) 2 (v c2 ) The capacitance of the parasitic capacitor C2 is related to the voltage v across the drain and source of the switch tube Q2 c2 I is a function of (i) 1 I is the current flowing through the switching tube Q1 2 I is the current flowing through the switching tube Q2 L Current flowing in and out of the junction of the switching transistor Q1 and the switching transistor Q2.
Based on this, an embodiment of the present invention proposes a power converter, as shown in fig. 3, including: the power conversion circuit 10 comprises at least one pair of switching tubes, wherein a first end of one switching tube of each pair of switching tubes is connected with a second end of the other switching tube; the control circuit 20 is connected to the power conversion circuit 10, and is configured to control the power conversion circuit 10, obtain an integrated charge value representing a total amount of charge change of one of the pair of switching tubes after the switching tube is turned off, and control the other switching tube of the pair of switching tubes to be turned on when the integrated charge value reaches a charge threshold.
The switching transistor may be a MOSFET, a SiC transistor, a GaN transistor, an IGBT module with a parallel schottky diode, or the like.
It should be noted that, when the switching tube is the MOSFET, the first end of the switching tube be the drain electrode of switching tube, the first end of switching tube be the source electrode of switching tube, for the IGBT module of taking parallelly connected schottky diode when the switching tube, the first end of switching tube be the collecting electrode of switching tube, the first end of switching tube be the projecting pole of switching tube.
The power conversion circuit may be any of a BUCK conversion circuit, a BOOST conversion circuit, an LLC conversion circuit, a double active bridge conversion circuit, a cyclic conversion circuit, a half-bridge circuit, and a full-bridge circuit, for example, for performing inversion, rectification, dc-dc conversion, or ac-ac conversion.
The power converter may be a DC-DC type power converter, a DC-AC type power converter, an AC-DC type converter, or the like.
In the embodiment, after one switching tube of the pair of switching tubes is turned off, an integral charge value representing the total charge variation amount of the pair of switching tubes is obtained, and when the integral charge value reaches a charge threshold value, the other switching tube of the pair of switching tubes is controlled to be turned on, so that zero-voltage turn-on of the switching tubes is realized, the conduction loss of parasitic diodes of the switching tubes is avoided, and the conversion efficiency of the power converter is improved.
Since the charge threshold value characterizes the pair of switching tubes in the ideal commutation period t 0 -t 1 Can be based on the voltage V across the pair of switching tubes bus The adjustment (i.e. the voltage between the first end of one switching tube and the second end of the other switching tube) is performed, so that an adaptive adjustment of the dead time can be achieved.
Specifically, ideal commutation period t 0 -t 1 The value of the charge variation amount delta Q of the pair of switch tubes is equal to the voltage V across the pair of switch tubes bus The parasitic capacitance of the switching tube is related to the capacitance of the switching tube connected in parallel (if the parasitic capacitance is connected in parallel additionally), and the total quantity delta Q of charge change and the voltage V of an ideal commutation period can be fitted under the condition that the capacitance value of the switching tube and the capacitance value of the capacitance connected in parallel are determined bus Is a relationship of (3). Thus, by applying a current i L Integrating to obtain an integrated charge value representing the real-time charge variation amount of the pair of switching tubes, and comparing the integrated charge value with a known voltage V bus When the values of the charge change total amounts delta Q of the corresponding ideal commutation time periods are equal, switching commutation is just completed at the moment, zero-voltage switching on of the switching tube can be realized at the moment, and the conduction loss of a parasitic diode of the switching tube is avoided.
As shown in fig. 4, the control circuit of the present embodiment controls the power conversion circuit of fig. 1, and starts to control the current i flowing out at the time when the switching transistor Q1 is turned off L Integrating to obtainThe integrated charge value reaches the corresponding voltage V bus Lower ideal commutation period t 0 -t 1 At the value of the total amount of charge change ΔQ, i.e. t 1 At moment, switching commutation is just completed, and at the moment, the switching tube Q2 is triggered to be switched on to realize zero-voltage switching on; similarly, at the time when the switching transistor Q2 is turned off, the current i flowing in starts to flow L Integrating when the integrated charge value reaches the value of the total amount of charge change DeltaQ, i.e. t 3 At the moment, switching commutation is just completed, and the switching tube Q1 is triggered to be switched on to realize zero-voltage switching.
According to the analysis, the integral charge value representing the total charge change amount of the pair of switching tubes is obtained at the turn-off time of one switching tube, the switch commutation completion time is determined according to the integral charge value and the known charge threshold value, and the switching tube which is complementarily conducted with the switching tube is turned on immediately after the parasitic diode of the switching tube which is complementarily conducted with the switching tube is commutated, so that the time period from t1 to t2 or from t4 to t5 shown in the graph 2 can be eliminated, the conduction loss generated by the conduction of the parasitic diode is avoided, the efficiency of the power converter is improved, and zero-voltage turn-on is realized.
In one embodiment, as shown in fig. 5, the control circuit 20 includes: a sampling circuit 201 for sampling the electric signals of a pair of switching transistors to obtain sampling signals; the integrating module 202 is connected with the sampling circuit 201 and integrates the sampling signal to obtain the integrated charge value; the controller 203 is connected to the integrating module 202 and includes a control module, where the control module provides a dead zone signal for controlling the integrating module and a control signal for controlling the at least one pair of switching tubes, and when one switching tube of the pair of switching tubes is turned off, the dead zone signal controls the integrating module 202 to start integrating the sampling signal, and when the integrated charge value reaches the charge threshold, the control signal controls the other switching tube of the pair of switching tubes to be turned on.
The electrical signal is a current signal representing the magnitude of the current flowing out and in at the connection point of the pair of switching tubes, and may be the current output at the connection point of the pair of switching tubes, or may be the current flowing through each switching tube of the pair of switching tubes, but is not limited thereto.
The sampling circuit 201 may be a current transformer or a sampling resistor, and other current sampling devices or apparatuses, and if the sampling circuit is a current transformer, the sampling circuit 201 also includes a conversion circuit for converting a current signal into a voltage signal.
The integrating module 202 may be constructed by integrating capacitor, switching device, amplifier, etc. to implement the integrating function.
The controller 203 may be an MCU (Microcontroller Unit: micro control unit), a DSP (Digital Signal Processing: digital signal processor), or the like.
In practical application, the charge threshold and the voltage V across a pair of switching tubes bus The correspondence of (c) may be represented by a table or a functional relationship and stored in the controller 203. The controller 203 controls the voltage V across the pair of switching tubes bus And determining a corresponding charge threshold value, so as to realize the self-adaptive adjustment of dead time.
Further, the control circuit 20 further includes: the detection module is used for detecting the turn-off time of the switching tube and providing detection signals to the control module.
The detection module may be a signal detection circuit inside the controller, for example, to determine the turn-off time of the switching tube by detecting a falling edge of a control signal of the switching tube.
In an alternative embodiment, the detection module may also be disposed outside the controller, so as to implement detection of the turn-off time of the switching tube.
In one embodiment, the control circuit 20 further comprises: and the comparison module is used for comparing the integrated charge value with the charge threshold value and outputting a comparison result to the control module.
It should be noted that the comparison module may be integrated inside the controller or may be disposed outside the controller.
The comparison module may implement its comparison function using a comparator or the like.
For some power converters, when the electric signal is a current signal, the sampling circuit can only sample and process the current signal with positive polarity, and when the actual current signal is a current signal with positive and negative polarities, the sampling circuit cannot normally sample the current signal with negative polarity.
To solve the above technical problem, in one embodiment, as shown in fig. 6, the control circuit 20 further includes: and the rectification circuit 204 is connected between the sampling circuit 201 and the integration module 202, and is used for rectifying the sampling signal and outputting the sampling signal to the integration module 202, and the integration module 202 integrates the rectified sampling signal to obtain the integrated charge value.
After the sampling signal with negative polarity passes through the rectifying circuit 204, the sampling signal with positive polarity is inverted, and at this time, the integrating module 202 can integrate the sampling signal.
The rectifier circuit 204 may be formed of rectifier diodes, such as rectifier bridges.
For some power converters, when the electric signal is a bipolar current signal, the current signal with a certain polarity does not act on the current conversion of the switching tube and is an invalid current.
To solve the above-mentioned technical problem, in one embodiment, as shown in fig. 7, the control circuit 20 further includes: and a rectification selection circuit 205 connected between the sampling circuit 201 and the integration module 202, and configured to rectify the sampling signal and selectively output a rectified sampling signal of a first polarity corresponding to a current flowing out of the connection point or a rectified sampling signal of a second polarity corresponding to a current flowing in the connection point according to a selection signal provided by the controller 203, where the integration module 202 integrates the rectified sampling signal of the first polarity and the rectified sampling signal of the second polarity to obtain the integrated charge value.
The selection signal is generated by the controller according to the voltage polarity at two ends of the pair of switching tubes and the turn-off time of the switching tubes.
In this embodiment, after a pair of switching tubes are turned off, the sampling signal corresponding to the current acting on the commutation is selected by the rectification selection circuit 205 to integrate, so that it is ensured that the zero voltage turn-on of the pair of switching tubes can be realized even in a special operating state of the power converter, the conduction loss of the parasitic diode of the switching tube is avoided, and the conversion efficiency of the power converter is improved.
It should be noted that, the first polarity may be positive, and the corresponding second polarity is negative; or the first polarity may be a negative polarity and the corresponding second polarity a positive polarity.
Specifically, when the voltage V across a pair of switching tubes bus When the voltage is a direct-current voltage, the switching tube at the high side of the pair of switching tubes is turned off, and the selection signal controls the output of the rectification selection circuit 205 to be switched into a sampling signal with a first polarity after rectification; and/or at the switching-off time of the switching tube positioned at the lower side of the pair of switching tubes, the selection signal controls the output of the rectification selection circuit 205 to be switched into the rectified sampling signal with the second polarity.
Voltage V across a pair of switching tubes bus In the case of ac voltage, the voltage V across the mains frequency positive half-cycle, i.e. a pair of switching tubes bus The output of the rectifying selection circuit 205 is controlled to be switched into a sampling signal with a first polarity after rectification by the selection signal at the turn-off time of a high-side switching tube in the pair of switching tubes; at the time of turning off the low-side switching transistor in the pair of switching transistors, the selection signal controls the output of the rectifying selection circuit 205 to be switched to the rectified sampling signal of the second polarity.
The switching tube located on the high side of the pair of switching tubes described in the present application means a switching tube located on the high potential of the pair of switching tubes; the switching tube positioned at the lower side of the pair of switching tubes refers to a switching tube positioned at a low potential in the pair of switching tubes.
As shown in fig. 8, the rectification selection circuit 205 includes: a separation unit 2051 for separating the sampled signal i cs The positive and negative polarities of the current flowing out of the connecting point are separated to obtain a sampling signal of a first polarity corresponding to the current flowing out of the connecting point and a sampling signal of a second polarity corresponding to the current flowing in of the connecting point; a rectifying unit 2052 configured to rectify the sampling signal of the first polarity and the sampling signal of the second polarity, respectively; a selection unit 2053 for selectively outputting the rectified sampling signal of the first polarity or the rectified sampling signal according to the selection signalObtaining a rectified sampling signal i by the sampling signal of the second polarity rec 。
Specifically, the separation unit 2051 may be configured by a plurality of components such as diodes and resistors; the rectifying unit 2052 may be constituted by a rectifying diode or the like; the selection unit 2053 may be configured by a selector, a resistor, a capacitor, or the like.
In a first example embodiment, the power converter is a BUCK or BOOST converter. As shown in fig. 9, the power converter includes a power conversion circuit 10 and a control circuit 20. The power conversion circuit 10 includes a pair of switching transistors and a capacitor C dc A capacitor C4 and an inductance L. The pair of switching tubes comprises a switching tube S1 positioned at a high side and a switching tube S2 positioned at a low side, the switching tube S1 and the switching tube S2 are complementarily conducted, a second end of the switching tube S1 is connected with a first end of the switching tube S2, and the voltage between the first end of the switching tube S1 and the second end of the switching tube S2 is V dc The connection point of the switching tube S1 and the switching tube S2 is connected with one end of the inductor L to output current i L The capacitor C1 and the capacitor C2 are parasitic capacitances of the switching tube S1 and the switching tube S2, respectively, and the capacitor C4 is connected between the other end of the inductor L and the common ground.
The control circuit 20 includes a sampling circuit 201, an integration module 202, and a controller 203. The controller 203 includes a control module 2031, a comparison module 206, and a detection module 207. When the capacitor C dc The side is the input side, and when the capacitor C4 side is the output side, the power converter is a BUCK converter; when the capacitor C dc When the output side is the output side and the capacitor C4 side is the input side, the power converter is a BOOST converter. In the case of a BUCK converter, the current i L To the right, i.e. out of the junction of switching tube S1 and switching tube S2, as indicated by the arrow in FIG. 9, current i in the case of a BOOST converter L The direction is opposite to that shown by the arrow in fig. 9, i.e., flows into the junction of the switching tube S1 and the switching tube S2.
Wherein the sampling circuit 201 samples the current i L Sampling to obtain a sampling signal i cs 。
The integration module 202 samples the signal i cs Integrating to obtain an integrated charge value Q int 。
Specifically, the integrating module 202 includes a selection switch ST, resistors R1 to R5, an integrating capacitor C3, and an operational amplifier OP. The resistor R1 is connected between the sampling circuit 201 and the point a of the selection switch ST, one end of the resistor R2 is connected with the point b of the selection switch ST, the other end of the resistor R2 is connected with one end of the integration capacitor C3 and grounded, the other end of the integration capacitor C3 is connected with the fixed end of the selection switch ST and the non-inverting input end of the operational amplifier OP, the resistor R5 is connected between the common ground and the inverting input end of the operational amplifier OP, the resistor R4 is connected between the inverting input end and the output end of the operational amplifier OP, and the resistor R3 is connected between the non-inverting input end and the output end of the operational amplifier OP.
The resistor R2 is used as a discharge unit, and the resistors R1, R3 to R5, the integrating capacitor C3 and the operational amplifier OP are connected to form an integrating unit. The selection switch ST is a single pole double throw switch, and the switch contact is controlled to be connected to the a point or the b point according to the dead zone signal DS. When the switch contact is connected to the point a, the integration unit integrates; when the switch contact is connected to the point b, the integration unit does not integrate, and the discharge unit starts discharging.
The detection module 207 is configured to detect a turn-off time of the switching tube S1 or the switching tube S2, and provide a detection signal to the control module 2031, for example, by detecting a turn-off edge of the control signal Vg1 of the switching tube S1 and a turn-off edge of the control signal Vg2 of the switching tube S2. The detection module 207 may be a signal detection circuit inside the controller 203, or may be independently disposed outside the controller 203, and this embodiment is illustrated as being disposed in the controller 203.
The comparison module 206 includes a comparator Comp for comparing the integrated charge value Q int And a charge threshold value Q ref Performs the comparison and outputs the comparison result to the control module 2031. The comparator Comp may be implemented by a comparator inside the controller or may be implemented by a separate analog comparator device, and this embodiment is illustrated by taking the comparison module 206 disposed in the controller 203 as an example.
The control module 2031 generates a dead zone signal DS based on the comparison result and the detection signal, and generates control signals Vg1, vg2 including dead zone time based on the dead zone signal and the reference control signal.
When the process is performedWhen the power converter is a BUCK converter, the switching tube S1 is a hard switch, and the control module 2031 performs soft-on control on the switching tube S2, where a specific control method is as follows: sampling circuit 201 pairs current i L Sampling in real time at arbitrary voltage V dc Next, when the detection module 207 detects the off edge of the control signal Vg1 of the switching tube S1, as shown in fig. 10, t corresponds to the control signal Vg1 6 At this time, the control module 2031 provides the dead zone signal DS of high level according to the detection signal outputted from the detection module 207, controls the switch contact of the selection switch ST to be connected to the a terminal, and the integration module 202 immediately starts integration when integrating the charge value Q int Reaching the charge threshold value Q ref At this time, as shown in FIG. 10, t corresponds to the control signal Vg1 7 At the moment, that is, when the formula (1) is satisfied, the voltage at two ends of the parasitic capacitor C2 of the switching tube S2 just drops to 0V, as shown by the waveform of "VS-synchronization" in fig. 10, the control signal Vg2 controls the switching tube S2 to be turned on, so that zero-voltage turn-on is realized, and meanwhile, the parasitic diode of the switching tube S2 will not be turned on, so that larger loss caused by conduction of the parasitic diode can be avoided. At this time, the comparator Comp in the comparison module 206 immediately outputs a high level signal, and the control module 2031 provides a dead zone signal DS of a low level according to the output signal of the comparator Comp, controls the switch contact of the selection switch ST to be connected to the b terminal, and discharges the charge on the integrating capacitor C3 through the resistor R2. The control method for the BUCK converter eliminates the conduction loss of the parasitic diode of the switching tube S2, reduces the loss of the switching tube S2 and improves the conversion efficiency of the BUCK converter.
When the power converter is a BOOST converter, the switching tube S2 is a hard switch, the control module 2031 performs soft-on control on the switching tube S1, and the control principle is the same as that of the BUCK converter for adaptively controlling the switching tube S2, except that the detection module 207 detects the off edge of the control signal Vg2 of the switching tube S2, and when integrating the charge value Q int Reaching the charge threshold value Q ref At this time, the switching tube S1 is turned on. Based on the control method for the BOOST converter, the conduction loss of the parasitic diode of the switching tube S1 is eliminated, the loss of the switching tube S1 is reduced, and the conversion efficiency of the BOOST converter is improved.
When the work isWhen the rate converter is a BUCK converter, the switching tube S1 is an active switching tube, and the switching tube S2 is a synchronous switching tube; when the power converter is a BOOST converter, the switching tube S1 is a synchronous switching tube, and the switching tube S2 is an active switching tube. In FIG. 10, "PWM-active" is the reference control signal of the active switching transistor without dead time, and "PWM-synchronous" is the reference control signal of the synchronous switching transistor, and dead time is set between the falling edge thereof and the reference control signal of the active switching transistor, such as t 8 ～t 9 The reference control signal may be generated by the control module 2031 according to specific control requirements of the power conversion circuit, as shown in the time period; current i L And sample signal i cs Is the waveform of the sampling signal i cs Is the input signal to the integration module 202; DS is a dead zone signal containing dead zone time; the "Vg-active" and "Vg-synchronous" are control signals of the active switching tube and the synchronous switching tube, respectively, generated by the control module 2031 according to the reference control signal and the dead time; the "VS-active" and "VS-synchronous" are voltage stress waveforms to which the active switching tube and the synchronous switching tube are subjected, respectively.
It should be noted that when the power converter is in steady state, the voltage V across the switching transistors S1 and S2 is due to dc The dead time is not required to be adaptively adjusted every period, the dead time just entering a steady state can be used as the dead time of every subsequent period, and control such as integration and comparison is not required every period, so that the loss is further reduced.
When integrating charge value Q int Reaching the corresponding charge threshold value Q ref At this time, the control module 2031 controls the integration module 202 to discharge until the integrated charge value Q int And down to 0.
In a second example embodiment, the power converter is an LLC converter. As shown in fig. 11, the power conversion circuit in the power converter comprises a pair of switch tubes and a capacitor C dc Output capacitance C out Inductance L and excitation inductance L m A resonant capacitor C5, a center tapped transformer T, and rectifier diodes D1 and D2. The pair of switching tubes comprises a switching tube S1 positioned at a high side and a switching tube S2 positioned at a low side, and a second end of the switching tube S1Is connected with the first end of the switch tube S2, and the voltage between the first end of the switch tube S1 and the second end of the switch tube S2 is V dc The connection point of the switching tube S1 and the switching tube S2 is connected with one end of an inductor L through a resonance capacitor C5 to output current i L . The other end of the inductor L is connected with the homonymous end of the primary winding of the transformer T, and the inductor L is excited m The primary side of the transformer T is connected, the homonymous end and the heteronymous end of the secondary side winding of the transformer T are respectively connected with the rectifier diodes D1 and D2, the rectifier diodes D1 and D2 are commonly connected with an output terminal, and the output capacitor C out Connected between the center tap of the secondary winding and the other output terminal.
The control circuit includes a sampling circuit 201, an integrating module 202, a rectifying circuit 204, and a controller 203. The controller 203 includes a control module 2031, a comparison module 206, and a detection module 207. The inductance L can be leakage inductance of the transformer T or independent inductance L m Is the excitation inductance of the transformer T.
The same points as those of the first exemplary embodiment will not be described again, and only the differences will be described below.
In this example embodiment, the switching tube S1 and the switching tube S2 are both soft-on, the controller 203 performs soft-on control on the switching tube S1 and the switching tube S2, and the corresponding detection module 207 is configured to detect the off time of the switching tube S1 and the switching tube S2.
The rectifying circuit 204 is connected between the sampling circuit 201 and the integrating module 202, and is configured to rectify the sampling signal to obtain a rectified sampling signal, and output the rectified sampling signal to the integrating module 202, where the integrating module 202 integrates the rectified sampling signal to obtain the integrated charge value.
The specific control method comprises the following steps: sampling circuit 201 pairs current i L The sampling signal is obtained by sampling in real time, and the rectifying circuit 204 rectifies the sampling signal in real time. Suppose that the current i in fig. 11 is specified L When positive current flows in the right direction, that is, when positive current flows through the connection point of the switching tube S1 and the switching tube S2, the current flows at an arbitrary voltage V dc Next, when the detection module 207 detects the falling edge of the control signal of the switching tube S1, as t corresponding to the control signal Vg1 in fig. 4 0 Time of day, dead zone signal DSThe switch contact of the control selection switch ST is connected to the a terminal, the current i L The steady state operation in the direction is positive current as indicated by the arrow in fig. 11. The integration module 202 immediately starts integrating the rectified sampled signal when the integrated charge value reaches the charge threshold Q ref When the voltage at the two ends of the parasitic capacitor C2 of the switching tube S2 just drops to 0V, the control signal Vg2 controls the switching tube S2 to be turned on, zero-voltage on is realized, and the parasitic diode of the switching tube S2 is not conducted, so that larger loss caused by the conduction of the parasitic diode can be avoided. At this time, the dead zone signal DS controls the switch contact of the selection switch ST to be connected to the b terminal, and the integrated charge value on the integrating capacitor C3 is discharged through the resistor R2.
When the detection module 207 detects the falling edge of the control signal Vg2 of the switching tube S2, as t corresponding to the control signal Vg2 in fig. 4 3 At this point in time, the dead zone signal DS controls the switching contact of the selection switch ST to be connected to the a terminal, at which time the current i L In steady state operation in the direction opposite to the arrow direction in fig. 11, is negative current, and the sampling circuit 201 samples the current i L Sampling to obtain a negative-polarity sampling signal, after the negative-polarity sampling signal passes through the rectifying circuit 204, the integrating module 202 immediately starts to integrate the rectified sampling signal, and when the integrated charge value reaches the charge threshold value Q ref When the voltage at the two ends of the parasitic capacitance C1 of the switching tube S1 just drops to 0V, namely the voltage meets the requirement of the formula (2), at the moment, the control signal Vg1 controls the switching tube S1 to be turned on, so that soft switching is realized, and the parasitic diode of the switching tube S1 is not conducted, so that larger loss caused by the conduction of the parasitic diode can be avoided. At this time, the dead zone signal DS controls the switch contact of the selection switch ST to be connected to the b terminal, and discharges the charge on the integrating capacitor C3 through the resistor R2.
The half-bridge LLC converter in FIG. 11 avoids parasitic diode conduction losses of the switching tube S1 and the switching tube S2, and improves the efficiency of the overall converter.
The second exemplary embodiment is exemplified by, but not limited to, a DAB converter, a half-bridge DC-DC converter, a full-bridge DC-DC converter, an active PFC circuit, a three-phase inverter bridge, a three-phase active rectifier bridge circuit, or the like.
In a third example embodiment, the power converter is an inverter, the input may be connected to a photovoltaic dc power source or an energy storage battery, etc., the dc power provided by the photovoltaic dc power source or the energy storage battery is inverted to ac power, and the power grid or the load may be supplied with power, where the photovoltaic dc power source is, for example, a single photovoltaic module, a single photovoltaic cell sub-string, a plurality of photovoltaic modules connected in series and/or parallel, a plurality of photovoltaic cell sub-strings connected in series and/or parallel, etc. Taking the example that the input end is connected with a photovoltaic direct current power supply and supplies power to a power grid, as shown in fig. 12, the power converter comprises: a power conversion circuit 10 and a control circuit 20.
Wherein the power conversion circuit 10 comprises an inverter circuit 101, the inverter circuit 101 being configured to invert direct current into alternating current; a transformer T connected to the inverter circuit 101 for boosting and dropping; a resonant circuit 103 connected with the secondary winding of the transformer T for realizing soft switching; the frequency conversion circuit 102 is connected with the resonant circuit 103 and comprises two pairs of switching tubes which are reversely connected and used for performing alternating and changing. The filter circuit 104 is connected to the output end of the frequency conversion circuit 102 for filtering to obtain an alternating voltage V which can be supplied to the power grid grid 。
After one of the pair of switching tubes in the frequency conversion circuit 102 is turned off, the integrating module 202 obtains a first integrated charge value representing the total amount of charge change of the pair of switching tubes, and when the first integrated charge value reaches a first charge threshold, the control module controls the other switching tube of the pair of switching tubes to be turned on.
In a positive power frequency half period of the output voltage of the frequency conversion circuit 102, at a switching tube turn-off time of a switching tube located at a high side in one of the two pairs of switching tubes, the integrating module 202 starts integrating the rectified sampling signal corresponding to the current flowing out from the connection point of the pair of switching tubes; at the switching-off time of the switching tube located at the lower side of the pair of switching tubes, the integrating module 202 starts integrating the rectified sampling signal corresponding to the current flowing into the connection point of the pair of switching tubes;
in the power frequency negative half period of the output voltage of the frequency conversion circuit 102, at the switching-off time of the switching tube located at the high side in the other pair of switching tubes, the integrating module 202 starts integrating the rectified sampling signal corresponding to the current flowing into the connection point of the pair of switching tubes; at the switching-off time of the switching tube located at the lower side of the pair of switching tubes, the integrating module 202 starts integrating the rectified sampling signal corresponding to the current flowing out from the connection point of the pair of switching tubes.
Specifically, the resonant circuit 103 is connected to one end of the secondary winding of the transformer T, and includes an inductance L and a resonant capacitor C5 connected in series, where the inductance L may be leakage inductance of the transformer T or may be an independent inductance.
The turn ratio of the primary winding and the secondary winding of the transformer T is 1: n.
The cycle conversion circuit 102 is a half-bridge type cycle converter, and includes two pairs of switching tubes connected in opposite directions, specifically, one pair of switching tubes includes a switching tube S3 located on a high side and a switching tube S5 located on a low side, the switching tube S3 and the switching tube S5 are complementarily turned on, and the other pair of switching tubes includes a switching tube S4 located on the low side and a switching tube S6 located on the high side, and the switching tube S4 and the switching tube S6 are complementarily turned on. The second end of the switching tube S3 is connected with the first end of the switching tube S5 through the switching tube S4, the second end of the switching tube S6 is connected with the first end of the switching tube S4 through the switching tube S5, the switching tubes S3 and S5 are reversely connected with the switching tubes S4 and S6, and the switching tube S4 and the switching tube S5 are connected to the point A and connected with the resonant circuit 103. The connection point a of the switching tube S4 and the switching tube S5 is the connection point of the switching tube S3 and the switching tube S5, and is also the connection point of the switching tube S4 and the switching tube S6, so that the current signal representing the magnitude of the current flowing out of and into the connection point of the switching tube S3 and the switching tube S5 is the current i flowing through the resonant circuit 103 L The current signal representing the magnitude of the current flowing out and in at the junction of the switching tube S4 and the switching tube S6 is also the current i flowing through the resonant circuit 103 L 。
The filter circuit 104 includes an inverter-side filter capacitor C f And an inversion side filter inductance L f Filter inductance L f Filtering the high-frequency switch current to obtain clean power frequency alternating current output current。
Further, the inverter circuit 101 includes at least one pair of switching tubes, and after one switching tube of the pair of switching tubes in the inverter circuit 101 is turned off, the integrating module 202 obtains a second integrated charge value representing the total amount of charge change of the pair of switching tubes, and controls the other switching tube of the pair of switching tubes to be turned on when the second integrated charge value reaches a second charge threshold.
Specifically, the inverter circuit may be a full-bridge circuit, or may be a half-bridge inverter circuit, taking a full-bridge circuit as an example. The inverter circuit 101 includes two pairs of switching transistors, wherein one pair includes a switching transistor S7 located at a high side and a switching transistor S8 located at a low side, and a second end of the switching transistor S7 is connected to a first end of the switching transistor S8; the other pair comprises a switching tube S9 positioned at the high side and a switching tube S10 positioned at the low side, and the second end of the switching tube S9 is connected with the first end of the switching tube S10; the switching tube S7 and the switching tube S8 are complementarily conducted; the switching tube S9 and the switching tube S10 are complementarily conducted. The intermediate connection point of the switching tubes S7 and S8 and the intermediate connection point of the switching tubes S9 and S10 are respectively connected with two ends of the primary winding of the transformer T. The current signal representing the magnitude of the current flowing out and in at the junction of the switching tube S7 and the switching tube S8 is the current i flowing through the resonant circuit 103 L The current signal representing the magnitude of the current flowing out and in at the junction of the switching tube S9 and the switching tube S10 is also the current i flowing through the resonant circuit 103 L 。
The input voltage of the inverter circuit 101, i.e. the voltage across the two pairs of switching tubes is V dc Is a direct current voltage. Parasitic capacitances C30, C40, C50, C60, C70, C80, C90, and C100 exist in the switching transistors S3 to S6 and the switching transistors S7 to S10, respectively.
As shown in fig. 13, the control circuit 20 includes a sampling circuit (not shown in the figure), an integrating module 202, a control module 2031, a detecting module 207, a comparing module 206, and a rectifying circuit 204.
The sampling circuit 201 is used for measuring the resonant current i L Sampling to obtain a sampling signal i cs 。
The rectifier circuit 204 provides the sampling signal i to the sampling circuit 201 cs Rectifying to obtain a rectified sampling signal i rec And provided to the integration module 202.
The integration module 202 samples the rectified sampling signal i rec Integrating to obtain a first integrated charge value Q representing the total charge variation of each pair of switching tubes in the cyclic conversion circuit 102 int1 And obtaining a second integrated charge value Q representing the total amount of charge variation for each pair of switching tubes in the inverter circuit 101 int2 。
The comparison module 206 is used for comparing the first integrated charge value Q int1 And a first charge threshold value Q ref1 Compares and outputs the comparison result to the control module 2031, and outputs the second integrated charge value Q int2 And the second charge threshold value Q ref2 Performs the comparison and outputs the comparison result to the control module 2031.
The detection module 207 is configured to detect the turn-off moments of the switching transistors S3 to S6 and the switching transistors S7 to S10, for example, by detecting the turn-off edges of the control signals Vg3 to Vg6 of the switching transistors S3 to S6 and the control signals Vg7 to Vg10 of the switching transistors S7 to S10.
The control module 2031 is configured to generate control signals Vg3 to Vg6 for controlling the switching transistors S3 to S6 and control signals Vg7 to Vg10 for controlling the switching transistors S7 to S10, and generate a first dead zone signal DS1 and a second dead zone signal DS2 according to the outputs of the detection module 206 and the comparison module 206.
Wherein the integration module 202 comprises: a first integrating circuit 2021 for rectifying the sampled signal i according to the first dead zone signal DS1 provided by the control module 2031 rec Integrating to obtain the first integrated charge value Q int1 The first dead zone signal DS1 is controlled by the control module 2031 according to the turn-off time of the switching tube in the frequency conversion circuit 102 and the first integrated charge value Q int1 And a first charge threshold value Q ref1 Is generated; a second integrating circuit 2022 for rectifying the sampled signal i according to the second dead zone signal DS2 provided by the control module 2031 rec Integrating to obtain the second integrated charge value Q int2 The second dead zone signal DS2 is controlled by the control module 2031 according to the off time of the switching tube in the inverter circuit 101 and the second integration powerLoad value Q int2 And a second charge threshold value Q ref2 Is generated.
The comparison module 206 includes: a first comparison unit 2061 for comparing the first integrated charge value Q int1 And the first charge threshold value Q ref1 The comparison is performed and the comparison result is output to the control module 2031, and the control module 2031 generates a first dead zone signal DS1 according to the detection signal corresponding to the switching tube in the frequency conversion circuit 102 and the comparison result output by the first comparison unit 2061 and provides the first dead zone signal DS1 to the first integration circuit 2021 in the integration module 202; a second comparison unit 2062 for comparing the second integrated charge value Q int2 And the second charge threshold value Q ref2 The comparison is performed and the comparison result is output to the control module 2031, and the control module 2031 generates a second dead zone signal DS2 based on the detection signal corresponding to the switching tube in the inverter circuit 101 and the comparison result of the second comparison unit output 2062 and supplies to the second integration circuit 2022 in the integration module 202.
Since the inverter provides an AC output, at an AC voltage V grid The output voltage of the cycloconverter 102 (i.e., the filter capacitor C f The voltage on) there are a positive mains frequency half cycle and a negative mains frequency half cycle. Taking the control of the frequency conversion circuit 102 as an example, the ac voltage V is the positive half period of the power frequency of the output voltage of the frequency conversion circuit 102 grid During the positive half period of (a), the control module 2031 controls the switching tube S4 and the switching tube S6 to keep the on state, the corresponding control signal Vg4 and control signal Vg6 are high level signals, the high level signals represent driving the switching tube to be on, and at this time, the switching tube S3 and the switching tube S5 are connected in series to bear the positive ac voltage V grid . The voltage between the first end of the switching tube S3 and the second end of the switching tube S5 is V grid . During the negative half-cycle of the power frequency at the output voltage of the frequency conversion circuit 102, i.e. the ac voltage V grid During the negative half period of (2), the control module 2031 controls the switching tube S3 and the switching tube S5 to keep the on state, the corresponding control signal Vg3 and control signal Vg5 are high level signals, and at this time, the switching tube S4 and the switching tube S6 are connected in series to bear the negative polarityCurrent voltage V grid . The voltage between the first end of the switching tube S6 and the second end of the switching tube S4 is-V grid 。
Fig. 14 is a schematic diagram of waveforms associated with a positive half-cycle of the power converter according to the third exemplary embodiment, in which PWM-S3 and PWM-S5 are reference control signals without dead zones of the switching tube S3 and the switching tube S5 inside the control module 2031, respectively, and do not participate in the direct control of the corresponding switching tube, and may be generated by the control module 2031 according to specific control requirements of the power conversion circuit. The control module 2031 performs logic conversion or program conversion on the reference control signals PWM-S3 and PWM-S5 and the dead zone signal DS1 to obtain the control signal Vg3 of the switching tube S3 and the control signal Vg5 of the switching tube S5. VS3 and VS5 are voltage stress waveforms to which the switching tube S3 and the switching tube S5 are subjected, respectively. Since the control signal Vg4 of the switching tube S4 and the control signal Vg6 of the switching tube S6 supplied from the control module 2031 are constant high level signals in the positive half cycle, the switching tubes S4 and S6 are kept in a normally-on closed state, and the related waveforms are not shown in fig. 14.
When the current signal i in fig. 12 is defined during the positive power frequency half period of the output voltage of the frequency conversion circuit 102 L When positive current flows in the right direction, that is, when positive current flows into the connection point of the switching tube S3 and the switching tube S5, the alternating voltage V in any positive half period grid Next, when the detection module 207 detects the off edge of the control signal Vg5 of the switching tube S5, the dead zone signal DS1 outputted by the control module 2031 controls the switch contact of the selection switch ST to be connected to the a terminal, and the current i L As shown by the arrow in fig. 12, the first integrating circuit 2021 immediately samples the rectified sampling signal i corresponding to the current flowing into the junction of the switching tube S3 and the switching tube S5, as a positive current in the steady-state operation in the direction rec Start integration when the first integrated charge value Q int1 Reaching the first charge threshold value Q ref1 (first charge threshold Q) ref1 According to the output voltage of the frequency conversion circuit and/or the parasitic capacitance of the switching tube and the external parallel capacitance of the frequency conversion circuit, and a first charge threshold Q ref1 With alternating voltage V grid Changes in real time) the parasitic power of the switching tube S3The voltage at two ends of the capacitor C30 just drops to 0V, at the moment, the control signal Vg3 controls the switch tube S3 to be turned on, soft switching is realized, and the parasitic diode of the switch tube S3 is not conducted, so that larger loss caused by the conduction of the parasitic diode can be avoided. At this time, the comparison module 206 immediately outputs a high level signal, and the control module 2031 controls the switch contact of the selection switch ST in the first integration circuit 2021 to be connected to the b terminal according to the dead zone signal DS1 provided by the output signal of the comparison module 206, and discharges the charge on the integration capacitor C3 through the resistor R2.
When the detection module 207 detects the off edge of the control signal Vg3 of the switching tube S3, the dead zone signal DS1 outputted by the control module 2031 controls the switch contact of the selection switch ST to be connected to the a terminal, and the current i L In steady-state operation in the direction opposite to that shown by the arrow in fig. 12, the first integrating circuit 2021 immediately samples the rectified sampling signal i corresponding to the current flowing out of the junction of the switching tube S3 and the switching tube S5, with a negative current, that is, the current flowing out of the junction of the switching tube S3 and the switching tube S5 rec Start integration when the first integrated charge value Q int1 Reaching the first charge threshold value Q ref1 When the voltage at two ends of the parasitic capacitor C50 of the switching tube S5 just drops to 0V, the control signal Vg5 controls the switching tube S5 to be turned on, zero voltage on is realized, and the parasitic diode of the switching tube S5 is not conducted, so that larger loss caused by the conduction of the parasitic diode can be avoided. At this time, the comparison module 206 immediately outputs a high level signal, and the control module 2031 controls the switch contact of the selection switch ST in the first integration circuit 2021 to be connected to the b terminal according to the dead zone signal DS1 provided by the output signal of the comparison module 206, and discharges the charge on the integration capacitor C3 through the resistor R2.
When the control principle is the same as that of the power frequency positive half period, the difference is that the detection module 207 detects the turn-off edge of the control signal of the switching tube S4 or the switching tube S6, and after the control, the control signals of the switching tube S4 and the switching tube S6 with the self-adaptive dead time are obtained.
For inverter circuit 101, switching tube S7 and switching tube S10 may have a conduction phase shift angle, and for adaptive dead time of switching tubes S7-S10The control is the same as the control principle of the secondary side switching tubes S3 to S6. The current i sampled by the sampling circuit 201 L Since the current is the secondary side of the transformer T, the turn ratio of the transformer T needs to be 1 for the switching transistors S7 to S10: n takes into account the rechecked integrated charge value. Second charge threshold value Q ref2 And an input voltage V of the inverter circuit 101 dc Related to a second charge threshold value Q ref2 According to the input voltage V of the inverter circuit 101 dc The turn ratio of the transformer T and/or the parasitic capacitance of the switching tubes in the inverter circuit 101 and the external parallel capacitance. For example, upon detecting the off edge of the control signal Vg7 of the switching tube S7, the dead zone signal DS2 controls the second integrating circuit 2022 to start rectifying the rectified sampling signal i rec Integrating to obtain a second integrated charge value Q int2 When the second integrated charge value Q int2 Reaching the second charge threshold value Q ref2 In the process, the control signal Vg8 controls the switching tube S8 to be turned on, so that zero voltage turn-on of the switching tube S8 is realized, and no parasitic diode conduction loss is generated. The specific control principle is similar to the adaptive dead time control principle of the switching transistors S3 to S6 in fig. 12, and will not be described again. But due to V dc Is a direct current voltage, so there is no difference in control between the positive half cycle and the negative half cycle.
The switching transistors S3 to S6 and the switching transistors S7 to S10 in fig. 12 are controlled by adopting adaptive dead time, that is, zero voltage turn-on of all the switching transistors is realized, and the conduction loss of the parasitic diode is zero, so that the loss of all the switching transistors is reduced, and the efficiency of the whole converter is improved.
When the first integral charge value Q int1 Reaching the first charge threshold value Q ref1 At this time, the control module 2031 controls the discharge of the first integration circuit 2021 until the first integrated charge value Q int1 Reducing to 0; when the second integrated charge value Q int2 Reaching the second charge threshold value Q ref2 At this time, the control module 2031 controls the second integration circuit 2022 to discharge until the second charge threshold value Q ref2 And down to 0.
Fig. 13 and 14 are schematic diagrams of control circuits and related waveforms for steady-state operation common to the exemplary embodiment. But in the actual operation of the device,a special state may exist. Taking the switching tube of the cycloconverter 102 as an example, and taking the case of the positive half period, the switching tube S3 or S5 is turned off at the moment when the current i L The direction or positive and negative polarity of (c) and i in FIG. 14 L In opposite directions, as shown in FIG. 15, i.e., t 6 ～t 7 、t 8 ～t 9 、t 10 ～t 11 Current i corresponding to time period L . The current at this time does not act on the commutation of the switching tube S3 and the switching tube S5, and the dead time is controlled by the dead current, which is an ineffective current, and cannot participate in integration, and the actual commutation start time is required to be equal to t in fig. 15 6 、t 8 、t 10 The moment when the absolute value of the current at the turn-off moment drops to 0, i.e. t 7 、t 9 、t 11 Time of day.
Fig. 16 is a schematic diagram of the structure of a control circuit in the fourth exemplary embodiment, replacing the rectifying circuit 204 in the third exemplary embodiment with the rectifying selection circuit 205.
In a positive power frequency half period of the output voltage of the frequency conversion circuit 102, a switching tube on a high side of a pair of switching tubes (a switching tube S3 and a switching tube S5) among the two pairs of switching tubes is turned off, and the selection signal controls the output of the rectification selection circuit 205 to be switched into a sampling signal of a first polarity after rectification; at the time when the switching tube positioned at the lower side of the pair of switching tubes is turned off, the selection signal controls the output of the rectification selection circuit 205 to be switched into a rectified sampling signal with a second polarity; in the power frequency negative half period of the output voltage of the frequency conversion circuit 102, the switching tube on the high side of the other pair of switching tubes (the switching tube S4 and the switching tube S6) is turned off, and the selection signal controls the output of the rectification selection circuit 205 to be switched into the sampling signal with the second polarity after rectification; at the time when the switching tube located at the lower side of the pair of switching tubes is turned off, the selection signal controls the output of the rectifying selection circuit 205 to be switched into the sampling signal of the first polarity after rectification.
The waveform of the output signal of the rectification select circuit 205 is as waveform i in fig. 15 rec As shown. Rectification by control of control module 2031Post-sampling signal i rec The value in the dead current time is 0, so the control of the integrated value and the dead time is not affected.
In the fourth exemplary embodiment, the control principle of the power frequency negative half period of the output voltage of the frequency conversion circuit 102 is the same as that of the power frequency positive half period, and taking the power frequency positive half period as an example, when the detection module 207 detects the off edge of the control signal Vg3 of the switching tube S3 or the control signal Vg5 of the switching tube S5, the integration module 202 starts integration, and when the corresponding charge threshold is reached, the integration is ended, and the complementary conduction is performed to turn on the zero voltage of the pair tube.
When the switching transistors S7 to S10 of the inverter circuit 101 are operated, the current waveforms are in the special operating state in fig. 15, so the control circuit and the control method in fig. 16 are also required, and the specific control principle is the same as the switching transistors S3 to S6, and will not be described again.
The control method for the power converter in the special operating state in the fourth example embodiment is equally applicable to the power converter in the normal operating state in the third example embodiment.
The third and fourth exemplary embodiments take only the half-bridge type frequency conversion module as an example, but not limited thereto, and the frequency conversion module 103 may be replaced by a full-bridge type one, and the adaptive dead zone control of the present invention may be applied.
Based on the above hardware embodiment, the embodiment of the present invention further provides a control method of a power converter, as shown in fig. 17, where the method includes:
s1702: after one switching tube of a pair of switching tubes is turned off, obtaining an integral charge value representing the total charge change amount of the pair of switching tubes;
s1704: and when the integrated charge value reaches a charge threshold value, controlling the other switching tube of the pair of switching tubes to be turned on.
In this embodiment, after one of the pair of switching tubes is turned off, an integrated charge value representing the total amount of charge variation of the pair of switching tubes is obtained, and when the integrated charge value reaches a charge threshold value, the other switching tube of the pair of switching tubes is controlled to be turned on. The zero-voltage switching-on of the switching tube is realized, the conduction loss of a parasitic diode of the switching tube is avoided, and the conversion efficiency of the power converter is improved.
In one embodiment, sampling the electrical signals of a pair of switching tubes to obtain a sampling signal;
and integrating the sampling signal to obtain the integrated charge value.
In an embodiment, the electrical signal is a current signal representative of the magnitude of current flowing out and in at the junction of the pair of switching tubes.
In an embodiment, the method further comprises:
and detecting the turn-off time of the switching tube, and starting to integrate the sampling signal when detecting that one switching tube in the pair of switching tubes is turned off.
In an embodiment, the method further comprises:
and rectifying the sampling signal, and integrating the rectified sampling signal to obtain the integrated charge value.
In an embodiment, the method further comprises:
and rectifying the sampling signals, and selecting the rectified sampling signals corresponding to the current flowing out of the connecting point or the sampling signals corresponding to the current flowing in of the connecting point to integrate according to the voltage polarities at the two ends of the pair of switching tubes and the turn-off time of the switching tubes to obtain the integrated charge value.
In an embodiment, when the voltages at two ends of a pair of switching tubes are positive, integrating the sampling signals corresponding to the current flowing out of the connection points at the switching tube turn-off time of the switching tube positioned at the high side in the pair of switching tubes; and/or
And integrating a sampling signal corresponding to the current flowing in the connection point at the switching-off time of the switching tube positioned at the lower side of the pair of switching tubes.
In an embodiment, the method further comprises:
and when the integrated charge value reaches a corresponding charge threshold value, starting discharging until the integrated charge value is reduced to 0.
The control principle of the embodiment of the method may refer to the description in the foregoing embodiment, so that a description is omitted.
The technical features of the above embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The foregoing examples represent only a few embodiments of the present application, which are described in more detail and are not to be construed as limiting the scope of the invention. It should be noted that it would be apparent to those skilled in the art that various modifications and improvements could be made without departing from the spirit of the present application, which would be within the scope of the present application. Accordingly, the scope of protection of the present application is to be determined by the claims appended hereto.
Claims (26)
1. A power converter, the power converter comprising:
The power conversion circuit comprises at least one pair of switching tubes, wherein the first end of one switching tube in each pair of switching tubes is connected with the second end of the other switching tube;
the control circuit is connected with the power conversion circuit and used for controlling the power conversion circuit, after one switching tube of the pair of switching tubes is turned off, an integral charge value representing the total charge change amount of the pair of switching tubes is obtained, and when the integral charge value reaches a corresponding charge threshold value, the other switching tube of the pair of switching tubes is controlled to be turned on.
2. The power converter of claim 1, wherein the control circuit comprises:
the sampling circuit is used for sampling the electric signals of the pair of switching tubes to obtain sampling signals;
the integration module is connected with the sampling circuit and used for integrating the sampling signal to obtain the integrated charge value;
the controller is connected with the integration module and comprises a control module, the control module provides a dead zone signal for controlling the integration module and a control signal for controlling at least one pair of switching tubes, when one switching tube in the pair of switching tubes is turned off, the dead zone signal controls the integration module to start integrating the sampling signal, and when the integrated charge value reaches a charge threshold value, the control signal controls the other switching tube in the pair of switching tubes to be turned on.
3. The power converter of claim 2, wherein the electrical signal is a current signal representative of the magnitude of current flowing out and in at a junction of the pair of switching tubes.
4. A power converter in accordance with claim 3, wherein said control circuit further comprises:
the detection module is used for detecting the turn-off time of the switching tube and providing detection signals to the control module;
and the comparison module is used for comparing the integrated charge value with the charge threshold value and outputting a comparison result to the control module.
5. A power converter in accordance with claim 3, wherein said control circuit further comprises:
and the rectification circuit is connected between the sampling circuit and the integration module and is used for rectifying the sampling signal and outputting the sampling signal to the integration module, and the integration module integrates the rectified sampling signal to obtain the integrated charge value.
6. A power converter in accordance with claim 3, wherein said control circuit further comprises:
the rectification selection circuit is connected between the sampling circuit and the integration module, rectifies the sampling signal, selectively outputs the rectified sampling signal with a first polarity corresponding to the current flowing out of the connection point or the rectified sampling signal with a second polarity corresponding to the current flowing in of the connection point according to the selection signal provided by the controller, and integrates the rectified sampling signal with the first polarity and the rectified sampling signal with the second polarity to obtain the integrated charge value.
7. The power converter of claim 6, wherein the power converter further comprises a power converter circuit,
when the voltages at two ends of the pair of switching tubes are direct-current voltages, switching off the switching tubes positioned at the high side in the pair of switching tubes, wherein the selection signal controls the output of the rectification selection circuit to be switched into a rectified sampling signal with a first polarity; and/or
And at the switching-off moment of a switching tube positioned at the low side of the pair of switching tubes, the selection signal controls the output of the rectification selection circuit to be switched into a rectified sampling signal with the second polarity.
8. The power converter of claim 6, wherein the power converter further comprises a power converter circuit,
when the voltages at two ends of the pair of switching tubes are alternating current voltages, the switching-off time of the high-side switching tube is positioned in the pair of switching tubes in the power frequency positive half period, and the selection signal controls the output of the rectification selection circuit to be switched into a sampling signal with a first polarity after rectification;
and the switching-off time of the low-side switching tube is positioned in the pair of switching tubes, and the selection signal controls the output of the rectification selection circuit to be switched into the rectified sampling signal with the second polarity.
9. The power converter of claim 6, wherein the rectification select circuit comprises:
The separation unit is used for separating the positive polarity and the negative polarity of the sampling signals output by the sampling circuit to obtain sampling signals of a first polarity corresponding to the current flowing out of the connection point and sampling signals of a second polarity corresponding to the current flowing in of the connection point;
the rectification unit is used for rectifying the sampling signal of the first polarity and the sampling signal of the second polarity respectively;
and the selection unit is used for selectively outputting the rectified sampling signal of the first polarity or the rectified sampling signal of the second polarity according to the selection signal.
10. The power converter according to claim 5 or 6, wherein the power conversion circuit comprises:
an inverter circuit for inverting the direct current into alternating current;
the resonant circuit is connected with the inverter circuit;
the frequency conversion circuit is connected with the resonant circuit and comprises two pairs of switching tubes which are connected in opposite directions and used for performing alternating current and alternating current conversion;
after one switching tube of a pair of switching tubes in the cycle conversion circuit is turned off, the integration module obtains a first integrated charge value representing the total charge change amount of the switching tubes, and when the first integrated charge value reaches a first charge threshold value, the control module controls the other switching tube of the switching tubes to be turned on.
11. The power converter of claim 10, wherein the power converter further comprises a power converter circuit,
in the power frequency positive half period of the output voltage of the frequency conversion circuit, the integration module starts integrating the rectified sampling signal corresponding to the current flowing out of the connection point of the pair of switching tubes at the switching-off moment of the switching tube positioned at the high side in one pair of switching tubes; the integration module starts integrating the rectified sampling signal corresponding to the current flowing into the connection point of the pair of switching tubes at the switching-off moment of the switching tube positioned at the low side of the pair of switching tubes;
in the power frequency negative half period of the output voltage of the frequency conversion circuit, the integration module starts integrating the rectified sampling signal corresponding to the current flowing into the connection point of the pair of switching tubes at the switching-off moment of the switching tube positioned at the high side in the other pair of switching tubes; at the switching-off time of the switching tube positioned at the lower side of the pair of switching tubes, the integrating module starts to integrate the rectified sampling signal corresponding to the current flowing out of the connecting point of the pair of switching tubes.
12. The power converter of claim 2, wherein when the integrated charge value reaches a corresponding charge threshold, the control module controls the integration module to discharge until the integrated charge value drops to 0.
13. The power converter of claim 10, wherein the power converter further comprises a power converter circuit,
the inverter circuit comprises at least one pair of switching tubes, after one switching tube of the pair of switching tubes in the inverter circuit is turned off, the integration module obtains a second integrated charge value representing the total charge change amount of the pair of switching tubes, and when the second integrated charge value reaches a second charge threshold value, the control module controls the other switching tube of the pair of switching tubes to be turned on.
14. The power converter of claim 13, wherein the integration module comprises:
the first integration circuit is used for integrating the rectified sampling signal according to a first dead zone signal to obtain a first integrated charge value, and the first dead zone signal is generated by the control module according to the turn-off time of a switching tube in the frequency conversion circuit and a comparison result of the first integrated charge value and the first charge threshold value;
and the second integration circuit is used for integrating the rectified sampling signal according to a second dead zone signal to obtain a second integrated charge value, and the second dead zone signal is generated by the control module according to the turn-off time of a switching tube in the inverter circuit and a comparison result of the second integrated charge value and the second charge threshold value.
15. The power converter of claim 13, wherein the power conversion circuit further comprises a transformer connected between the inverter circuit and the frequency conversion circuit;
the first charge threshold is determined according to the output voltage of the frequency conversion circuit and/or the parasitic capacitance of a switching tube in the frequency conversion circuit and an external parallel capacitor;
the second charge threshold is determined according to an input voltage of the inverter circuit, a turn ratio of the transformer, and/or a parasitic capacitance of a switching tube in the inverter circuit and an external parallel capacitance.
16. The power converter of claim 14, wherein when a first integrated charge value reaches a first charge threshold, the control module controls the first integrating circuit to discharge until the first integrated charge value drops to 0;
when the second integrated charge value reaches a second charge threshold, the control module controls the second integration circuit to discharge until the second integrated charge value drops to 0.
17. The power converter of claim 1, wherein the power conversion circuit is one of a BUCK conversion circuit, a BOOST conversion circuit, an LLC conversion circuit, a dual active bridge conversion circuit, a cycloconverter circuit, a half-bridge circuit, and a full-bridge circuit.
18. The power converter according to claim 1, characterized in that the power converter is a DC-DC type power converter or a DC-AC type power converter or an AC-DC type converter.
19. A control method of a power converter for a power converter according to any one of claims 1 to 18, the method comprising:
after one switching tube of a pair of switching tubes is turned off, obtaining an integral charge value representing the total charge change amount of the pair of switching tubes;
and when the integrated charge value reaches a corresponding charge threshold value, controlling the other switching tube of the pair of switching tubes to be turned on.
20. The method of claim 19, wherein the step of determining the position of the probe comprises,
sampling the electric signals of a pair of switching tubes to obtain sampling signals;
and integrating the sampling signal to obtain the integrated charge value.
21. The method of claim 20, wherein the electrical signal is a current signal representative of the magnitude of current flowing out and in at the junction of the pair of switching tubes.
22. The method of claim 21, wherein the method further comprises:
and detecting the turn-off time of the switching tube, and starting to integrate the sampling signal when detecting that one switching tube in the pair of switching tubes is turned off.
23. The method of claim 21, wherein the method further comprises:
and rectifying the sampling signal, and integrating the rectified sampling signal to obtain the integrated charge value.
24. The method of claim 21, wherein the method further comprises:
and rectifying the sampling signals, and selecting the rectified sampling signals corresponding to the current flowing out of the connecting point or the sampling signals corresponding to the current flowing in of the connecting point to integrate according to the voltage polarities at the two ends of the pair of switching tubes and the turn-off time of the switching tubes to obtain the integrated charge value.
25. The method of claim 21, wherein the step of determining the position of the probe is performed,
when the voltages at the two ends of the pair of switching tubes are positive, integrating sampling signals corresponding to the current flowing out of the connecting point at the switching tube switching-off moment of the switching tube positioned at the high side in the pair of switching tubes; and/or
And integrating a sampling signal corresponding to the current flowing in the connection point at the switching-off time of the switching tube positioned at the lower side of the pair of switching tubes.
26. The method of claim 19, wherein the method further comprises:
And when the integrated charge value reaches a corresponding charge threshold value, starting discharging until the integrated charge value is reduced to 0.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN202311658533.4A CN117713508A (en) | 2023-12-05 | 2023-12-05 | Power converter and control method thereof |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311658533.4A CN117713508A (en) | 2023-12-05 | 2023-12-05 | Power converter and control method thereof |
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| CN117713508A true CN117713508A (en) | 2024-03-15 |
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