CN110707931A - LLC resonant converter and control method - Google Patents

LLC resonant converter and control method Download PDF

Info

Publication number
CN110707931A
CN110707931A CN201910840399.7A CN201910840399A CN110707931A CN 110707931 A CN110707931 A CN 110707931A CN 201910840399 A CN201910840399 A CN 201910840399A CN 110707931 A CN110707931 A CN 110707931A
Authority
CN
China
Prior art keywords
switching tube
switching
inverter circuit
transformer
llc resonant
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN201910840399.7A
Other languages
Chinese (zh)
Inventor
余逸群
李思远
王志燊
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mornsun Guangzhou Science and Technology Ltd
Original Assignee
Mornsun Guangzhou Science and Technology Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Mornsun Guangzhou Science and Technology Ltd filed Critical Mornsun Guangzhou Science and Technology Ltd
Priority to CN201910840399.7A priority Critical patent/CN110707931A/en
Publication of CN110707931A publication Critical patent/CN110707931A/en
Priority to PCT/CN2020/092918 priority patent/WO2021042773A1/en
Pending legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/3353—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having at least two simultaneously operating switches on the input side, e.g. "double forward" or "double (switched) flyback" converter
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
    • H02M7/5387—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration
    • H02M7/53871—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration with automatic control of output voltage or current
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
    • H02M7/539—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters with automatic control of output wave form or frequency
    • H02M7/5395—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters with automatic control of output wave form or frequency by pulse-width modulation
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0048—Circuits or arrangements for reducing losses
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/4815—Resonant converters
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Dc-Dc Converters (AREA)

Abstract

The invention discloses an LLC resonant converter and a control method thereof, wherein the LLC resonant converter is low in design difficulty and comprises an inverter circuit, an LLC resonant cavity, a transformer and a rectifier network which are sequentially connected from input to output; the LLC resonant cavity comprises a resonant inductor Lr, an excitation inductor Lm and a resonant capacitor Cr, and a bidirectional switch is additionally arranged; the resonant inductor Lr and the resonant capacitor Cr are connected in series between the output end 1 of the inverter circuit and the end 1 of the primary coil of the transformer, the output end 2 of the inverter circuit is connected with the end 2 of the primary coil of the transformer, the excitation inductor Lm is connected in parallel with the primary coil of the transformer, the end 1 of the bidirectional switch is connected with the end 1 of the primary coil of the transformer by being connected between the resonant inductor Lr and the resonant capacitor Cr, and the end 2 of the bidirectional switch is connected with the end 2 of the primary coil of the transformer; the resonant inductor Lr is connected between the end 1 of the bidirectional switch and the end 1 of the primary coil of the transformer, and the resonant capacitor Cr is connected between the end 1 of the bidirectional switch and the output end No. 1 of the inverter circuit.

Description

LLC resonant converter and control method
Technical Field
The invention relates to the technical field of switching converters, in particular to an LLC resonant converter and a control method thereof.
Background
With the rapid development of the power electronic field, the application of the switching converter is more and more extensive. More requirements are put on switching converters: high power density, high reliability and small volume. An LLC resonant converter, as a resonant converter, has many advantages, such as low noise, low stress, low switching losses, etc. However, the conventional LLC resonant converter generally needs to adjust the output voltage by changing the switching frequency, and when the load or the input voltage fluctuates, the switching frequency needs to be changed in a wide range, which brings great difficulties to the design, analysis and control of the converter. When the voltage gain is wide, the efficiency of the traditional variable frequency control LLC resonant converter is obviously reduced.
For an LLC resonant converter controlled by a fixed frequency, a traditional control method adopts phase shift control, but because the current flowing when the switching tubes on a leading bridge arm and a lagging bridge arm on a primary side are switched on is different, the soft switching of the lagging bridge arm is difficult to realize, which is the inherent defect of the traditional phase shift control. In this control mode, the hysteresis bridge arm still can realize soft switching under the maximum phase shift angle. The larger the phase shift angle is, the wider the gain range is, and due to the foregoing concerns, the phase shift angle is limited, so that the gain range of the conventional LLC resonant converter with fixed frequency and phase shift control cannot be made wide.
In order to solve the problem that soft switching of a lagging bridge arm is difficult to realize in the traditional LLC resonant converter controlled by fixed frequency shift phase, the LLC resonant converter has an application number of 201410777221.X, namely the invention application named as 'a resonant converter and a control method thereof', and is hereinafter referred to as background document 1 for short, and the structure of the LLC resonant converter capable of realizing fixed frequency control is shown, as shown in figure 1, a bidirectional switch is added on a secondary side of the LLC resonant converter, output voltage stabilization is realized by controlling a phase shift angle of an original secondary side switching tube, and as primary side switches S1 and S4 are simultaneously turned on and off and S2 and S3 are simultaneously turned on and off, a leading bridge arm and a lagging bridge arm do not exist, so that the phase shift angle can be larger, and a corresponding gain range can be wider. But the bidirectional switch on the secondary side needs to be driven in an isolation mode, which brings great inconvenience to the drive control design of the circuit.
An invention application No. 201810587249.5 entitled full bridge resonant DC-DC converter with wide voltage output range and modulation method, hereinafter referred to as background document 2, shows an LLC resonant converter, which, as shown in fig. 2, implements output voltage stabilization by adding a bidirectional switch in a primary side resonant cavity, constructing a boost circuit with a primary side bridge arm and a resonant inductor, and controlling phase shift angles of the bidirectional switch and the primary side switching tubes, and because the primary side switches S1 and S4 are turned on and off simultaneously, and S2 and S3 are turned on and off simultaneously, there are no leading bridge arm and lagging bridge arm, so the phase shift angle can be made larger, and the corresponding gain range can be made wider. But because of the existence of the boost circuit, the stress of the device is large, which brings some inconvenience to the design of the converter.
Disclosure of Invention
The first technical problem to be solved by the present invention is to provide an LLC resonant converter with low design difficulty.
A second technical problem to be solved by the present invention is to provide a control method for the LLC resonant converter.
The first technical problem of the invention is solved by the following scheme: an LLC resonant converter comprises an inverter circuit, an LLC resonant cavity, a transformer and a rectifier network which are sequentially connected from input to output;
the LLC resonant cavity comprises a resonant inductor Lr, an excitation inductor Lm and a resonant capacitor Cr, and a bidirectional switch is additionally arranged; the resonant inductor Lr and the resonant capacitor Cr are connected in series between the output end 1 of the inverter circuit and the end 1 of the primary coil of the transformer, the output end 2 of the inverter circuit is connected with the end 2 of the primary coil of the transformer, the excitation inductor Lm is connected in parallel with the primary coil of the transformer, the end 1 of the bidirectional switch is connected with the end 1 of the primary coil of the transformer by being connected between the resonant inductor Lr and the resonant capacitor Cr, and the end 2 of the bidirectional switch is connected with the end 2 of the primary coil of the transformer;
the characteristic lies in that the resonance inductance Lr is connected between the 1 end of the two-way switch and the 1 end of the primary coil of the transformer, and the resonance capacitance Cr is connected between the 1 end of the two-way switch and the No. 1 output end of the inverter circuit.
The bidirectional switch is positioned on the primary side of the transformer, the isolation driving problem is not needed to be considered, the resonant capacitor Cr is placed in front of the bidirectional switch, the resonant inductor Lr is placed behind the bidirectional switch, and the booster circuit in the background document 2 is damaged, so that the problem of large stress of devices is solved.
It should be noted that the terminals 1 and 2 stated above are only given reference numerals for convenience of description, and correspond to the upper input/output terminal and the lower input/output terminal of the inverter circuit, the bidirectional switch and the primary winding of the transformer, respectively, if corresponding to fig. 3.
The inverter circuit is a full-bridge inverter circuit composed of four switching tubes S1, S2, S3 and S4, wherein the switching tubes S1 and S2 are respectively used for controlling whether the anode of an input power Vin is communicated with the No. 1 and No. 2 output ends of the inverter circuit, and the switching tubes S3 and S4 are respectively used for controlling whether the No. 1 and No. 2 output ends of the inverter circuit are communicated with the cathode of the input power Vin.
The inverter circuit may also be a half-bridge inverter circuit. When the primary side adopts a half-bridge inverter circuit, the number of the switching tubes on the primary side is reduced from 6 to 4, so that the number of devices is saved, and the inverter is suitable for medium and small power occasions.
The bidirectional switch is composed of two switching tubes S5 and S6 which are connected in series in an opposite direction, wherein a parasitic diode points to the connection end of the bidirectional switch, the resonant inductor Lr and the resonant capacitor Cr and is a switching tube S5.
The rectification network adopts a full-wave rectification structure, such as a full-bridge rectification structure, and the full-bridge rectification structure is composed of rectifier diodes or switching tubes.
The second technical problem of the invention is solved by the following scheme: the control method of the LLC resonant converter is characterized in that the LLC resonant converter is controlled by using fixed-frequency PWM (Pulse Width Modulation for short).
Specifically, the method comprises the following steps: switching frequencies of the switching tubes S1-S6 are equal and fixed, the switching tube S1 and the switching tube S5 are complementarily conducted, the switching tube S2 and the switching tube S6 are complementarily conducted, the switching tube S1 and the switching tube S4 are simultaneously conducted and simultaneously turned off, the switching tube S2 and the switching tube S3 are simultaneously conducted and simultaneously turned off, the duty ratio of the switching tube S1 is equal to the duty ratio of the switching tube S2, but not more than 0.5, but 180 degrees out of phase, the duty ratio of the switching tube S5 is equal to the duty ratio of the switching tube S6, but not less than 0.5, but not 180 degrees out of phase, the control of the output voltage is realized by adjusting the duty ratio of the switching tube S1, the larger the duty ratio of the switching tube S1 is, the larger the gain of the.
Compared with the prior art, the invention has the following beneficial effects:
1) compared with the background document 1, the bidirectional switch is positioned on the primary side of the transformer, the isolation driving problem is not required to be considered, and the difficulty of circuit driving design is reduced; compared with the background document 2, the invention changes the positions of the resonant inductor Lr and the resonant capacitor Cr in fig. 2, changes the original booster circuit into a step-down circuit, solves the problem of larger stress of the device, and outputs the current I in fig. 40The trend of the change (gradual change, no jump) can also be seen. In a word, the LLC resonant converter with the structure reduces the design difficulty of the LLC resonant converter, and can adopt fixed-frequency PWM control.
2) When the bidirectional switch is switched on, the energy of the resonant current is stored in a loop formed by the excitation inductor Lm, the resonance inductor Lr and the bidirectional switch in the circulation stage and does not flow through the resonant capacitor Cr, and the parasitic resistance of the resonant capacitor Cr is beneficial to reducing the loss of the energy on the parasitic resistance of the resonant capacitor Cr, so that the circuit structure can improve the working efficiency compared with the comparison document 2;
3) the invention has excellent comprehensive performance: the invention adopts fixed-frequency PWM control, has small frequency conversion range, low requirements on magnetic elements such as a transformer, an inductor and the like, no leading bridge arm and lagging bridge arm, wide voltage gain range, high efficiency, small stress of devices and low difficulty in circuit control and drive design; in addition, in terms of gain range, the present invention can realize a wider gain range than that of the background documents 1 and 2, and since the fixed frequency shift phase control cannot be combined with the half-bridge inverter circuit, and the gain range of the half-bridge inverter circuit is half of that of the full-bridge inverter circuit, the present invention can realize a wider gain range.
Drawings
Fig. 1 is a schematic diagram of an LLC resonant converter shown in background document 1;
fig. 2 is a schematic diagram of the LLC resonant converter shown in background document 2;
FIG. 3 is a schematic diagram of an LLC resonant converter in accordance with a preferred embodiment of the invention;
FIG. 4 is a diagram illustrating the main operating waveforms of the LLC resonant converter with fixed frequency control according to the preferred embodiment of the invention;
fig. 5 to 10 are equivalent circuit diagrams of each switching mode when the LLC resonant converter of the preferred embodiment of the present invention adopts fixed frequency control.
Detailed Description
As shown in fig. 3, the LLC resonant converter of the present embodiment includes an inverter circuit 10, an LLC resonant cavity 20, a transformer T, and a rectifier network 30, which are connected in sequence from input to output. In the figure, Vin is the input power supply of the converter, and Ro is the output load R of the converter0。
The inverter circuit 10 is a full-bridge inverter circuit composed of a switch tube S1, a switch tube S2, a switch tube S3, and a switch tube S4. The LLC resonant cavity 20 includes resonant inductor Lr, excitation inductor Lm, and resonant capacitor Cr, and is further provided with a bidirectional switch formed by a switch tube S5 and a switch tube S6. The rectifier network 30 is a full bridge rectifier circuit consisting of 4 diodes D1-D4 and connected with an output filter capacitor C in parallel0And (4) forming.
The drain of the switch tube S1 is connected to the drain of the switch tube S2 and the positive terminal of the input power Vin, the source of the switch tube S1 is connected to the drain of the switch tube S3 and one end of the resonance capacitor Cr, the other end of the resonance capacitor Cr is connected to one end of the resonance inductor Lr and the drain of the switch tube S5, the other end of the resonance inductor Lr is connected to one end of the excitation inductor Lm and the 1 end of the primary winding Np of the transformer T, the 2 end of the transformer T is connected to the other end of the excitation inductor Lm, the source of the switch tube S2, the drain of the switch tube S4 and the drain of the switch tube S6, the source of the switch tube S4 is connected to the source of the switch tube S3 and the negative electrode of the input power Vin, and the source of the switch tube S483; the 1 end of the secondary winding Ns of the transformer T is connected to the anode of the secondary rectifying diode D1 and the cathode of the secondary rectifying diode D3, the cathode of the secondary rectifying diode D1 is connected to the cathode of the secondary rectifying diode D2, one end of the secondary output filter capacitor Co and one end of the output load Ro, the other end of the output load Ro is connected to the other end of the secondary output filter capacitor Co, the anode of the secondary rectifying diode D3 and the anode of the secondary rectifying diode D4, and the cathode of the secondary rectifying diode D4 is connected to the anode of the secondary rectifying diode D2 and the 2 end of the secondary winding Ns of the transformer T.
The ends 1 of the primary winding and the secondary winding of the transformer are homonymous ends, and the ends 2 of the primary winding and the secondary winding of the transformer are homonymous ends.
The LLC resonant converter may adopt the following fixed-frequency PWM control method: switching frequencies of the switching tubes S1-S6 are equal and fixed, the switching tube S1 and the switching tube S5 are complementarily conducted, the switching tube S2 and the switching tube S6 are complementarily conducted, the switching tube S1 and the switching tube S4 are simultaneously conducted and simultaneously turned off, the switching tube S2 and the switching tube S3 are simultaneously conducted and simultaneously turned off, the duty ratio of the switching tube S1 is equal to the duty ratio of the switching tube S2, but not more than 0.5, but 180 degrees out of phase, the duty ratio of the switching tube S5 is equal to the duty ratio of the switching tube S6, but not less than 0.5, but not 180 degrees out of phase, the control of the output voltage is realized by adjusting the duty ratio of the switching tube S1, the larger the duty ratio of the switching tube S1 is, the larger the gain of the.
In practical implementation, a reasonable dead time must be set between the switching signals of the switching tube S1 and the switching tube S5 to realize soft switching of the switching tube S1, the switching tube S4 and the switching tube S5; a reasonable dead time must be set between the switching signals of the switching tube S2 and the switching tube S6 to realize soft switching of the switching tube S2, the switching tube S3 and the switching tube S6. Coss 1-Coss 6 represent output capacitances to the sixth switching tubes S1-S6, respectively.
The following describes the operation process of the LLC resonant converter using fixed-frequency PWM control with reference to fig. 3.
In this embodiment, the parameters are selected as follows: lr is 220nH, and the total weight of the catalyst,lm is 800nH, Cr is 82nF, and the input voltage range is 36-75 VDC. The turn ratio of the primary side to the secondary side of the transformer is 2: 1. FIG. 4 is a diagram of the main operating waveforms of the resonant converter under constant-frequency PWM control, where Vgs1/4 is the driving signal of the switch tubes S1 and S4, Vgs2/3 is the driving signal of the switch tubes S2 and S3, Vgs5 is the driving signal of the switch tube S5, Vgs6 is the driving signal of the switch tube S6, Vc, iLr, iLm, i0Respectively representing the voltage across Cr, the current through Lr, the current through Lm and the current through resistor R0The current of (2). As can be seen from FIG. 4, the present invention outputs a current I0The change is gentle and the stress of the device is small. The LLC resonant converter has six switching modes in a half cycle, which are shown in fig. 5-10, respectively (the working modes of the LLC resonant converter in the second half cycle and the first half cycle are symmetrical, which can also be seen from the waveform diagram, and generally, the description of the LLC resonant converter only describes the half cycle).
Switched mode 1[ t ]0，t1]: as shown in fig. 5, at t0Before the moment, the switch tube S6 is conducted, the switch tube S5 is turned off, and the body diode bears reverse voltage and is cut off in the reverse direction; at the time t0, the switch tube S1 and the switch tube S4 are switched on at zero voltage; the secondary side rectifier diode D1 and the secondary side rectifier diode D4 are conducted, and the current flowing through the diodes is in direct proportion to the difference value of the resonance current and the excitation current; the voltage at two ends of the excitation inductor Lm is output and clamped to nVO (n is the turn ratio of the transformer); the primary side resonance inductor Lr and the resonance capacitor Cr participate in resonance, the resonance current iLr is a standard sine wave and is a negative value, and the excitation inductor current iLm is linearly increased but is smaller than the resonance current iLr;
switched mode 2[ t ]1，t2]: as shown in fig. 6, at t1At the moment, the resonant current iLr crosses zero; the secondary side rectifier diode D1 and the secondary side rectifier diode D4 are continuously conducted; the voltage at two ends of the excitation inductor Lm is output and clamped to nVO(ii) a The primary side resonance inductor Lr and the resonance capacitor Cr participate in resonance, the resonance current iLr is a standard sine wave and is a positive value, and the excitation inductor current iLm is linearly increased but is smaller than the resonance current iLr;
switching mode 3[ t ]2，t3]: as shown in fig. 7, at t2The time switch tube S1 and the switch tube S4 are turned offThe resonant current iLr is still larger than the excitation inductor current iLm, and the secondary rectifier diode D1 and the secondary rectifier diode D4 are continuously conducted; the resonant current iLr is supplied to the switch tube S1 and the output capacitor C of the switch tube S4oss1、Coss4Charging, and outputting a capacitor C to the switch tube S2 and the switch tube S3oss2、Coss3Discharged to the output capacitor C of the switch tube S5oss5Discharging; when the capacitance Coss5When the voltage at the two ends drops to zero, the body diode of the switch tube S5 is conducted, so as to provide a condition for the switch tube S5 to realize zero voltage switching-on.
Switch mode 4[ t ]3，t4]: as shown in fig. 8, at t3When the switch tube S5 is switched on at zero voltage, the switch tube S6 is continuously conducted with the secondary side rectifier diode D1 and the secondary side rectifier diode D4; the excitation inductor Lm is still clamped by the output voltage, the excitation current iLm continues to increase linearly, and the resonant current iLr decreases linearly;
switching mode 5[ t ]4，t5]: as shown in fig. 9, at t4At the moment, the resonant current iLr is equal to the exciting current iLm, the current flowing through the secondary side rectifier diode D1 naturally passes through 0, and the secondary side rectifier diode D1 and the secondary side rectifier diode D4 are turned off at zero current, so that the problem of reverse recovery of the diodes is solved; the switch tube S5 and the switch tube S6 are continuously conducted, and the exciting current and the resonant current iLr are equal and are kept unchanged;
switched mode 6[ t ]5，t6]: as shown in FIG. 10, t5At the moment, the switch tube S6 is turned off, and the switch tube S5 continues to be turned on; the resonant current iLr is equal to the exciting current iLm, and the secondary rectifier diode is still in a reverse cut-off state; the resonant current iLr is supplied to the switch tube S1 and the output capacitor C of the switch tube S4oss1、Coss4Charging the output capacitor C of the switch tube S2 and the switch tube S3oss2、Coss3Discharged to the output capacitor C of the switch tube S6oss6Charging; when the capacitance Coss2、Coss3When the voltage of the two ends is reduced to 0, the body diode tubes of the switch tube S2 and the switch tube S3 are conducted, so that a condition is provided for realizing zero-voltage switching-on of the switch tube S2 and the switch tube S3; at time t6, ZVS is realized by the switching tube S2 and the switching tube S3, and the circuit enters the second half cycle.
According to the working process description of the converter, all switching devices of the converter can realize zero-voltage switching-on, all rectifying devices on the secondary side can realize zero-current switching-off, the problem of reverse recovery of diodes does not exist, and all switching devices can realize soft switching.
The bidirectional switch is positioned on the primary side of the transformer, the isolation driving problem is not required to be considered, and the difficulty of circuit driving design is reduced. The invention changes the positions of the resonant inductor Lr and the resonant capacitor Cr in the figure 2, changes the original booster circuit into a voltage reduction circuit and solves the problem of larger stress of devices. Therefore, the LLC resonant converter with the structure reduces the design difficulty of the LLC resonant converter on the whole.
When the bidirectional switch is conducted, the energy of the resonant current is stored in a loop formed by the excitation inductor Lm, the resonant inductor Lr and the bidirectional switch in the circulation stage and does not flow through the resonant capacitor Cr, and the parasitic resistance of the resonant capacitor Cr is beneficial to reducing the loss of the energy on the parasitic resistance of the resonant capacitor Cr.
The invention realizes output voltage stabilization by controlling the duty ratio, realizes fixed frequency PWM control, is convenient for the design of magnetic elements such as a transformer and the like, also reduces the circuit driving design difficulty and the device stress, realizes the soft switching of all switching devices, does not have an advance bridge arm and a lag bridge arm, has wide voltage gain range, high efficiency and high power density, can adopt a full bridge or a half bridge as an inverter circuit, can realize a voltage gain range wider than a fixed frequency shift phase, and meets the requirement of a wide voltage gain range conversion occasion. In summary, the converter of the present invention has excellent overall performance.
The above embodiments are only for the purpose of helping understanding the inventive concept of the present application, and are not intended to limit the present invention, for example, the switching transistors S5 and S6 of the present invention may also be implemented by a common drain reverse series connection (the respective control timings are not changed), the rectifying network may also be implemented by other full-wave rectifying circuits, the upper rectifying diode may also be replaced by a switching transistor, etc., in short, any modifications, equivalents, improvements, etc. made by those skilled in the art without departing from the principle of the present invention shall be included in the protection scope of the present invention.

Claims (9)

1. An LLC resonant converter comprises an inverter circuit, an LLC resonant cavity, a transformer and a rectifier network which are sequentially connected from input to output;
the LLC resonant cavity comprises a resonant inductor Lr, an excitation inductor Lm and a resonant capacitor Cr, and a bidirectional switch is additionally arranged; the resonant inductor Lr and the resonant capacitor Cr are connected in series between the output end 1 of the inverter circuit and the end 1 of the primary coil of the transformer, the output end 2 of the inverter circuit is connected with the end 2 of the primary coil of the transformer, the excitation inductor Lm is connected in parallel with the primary coil of the transformer, the end 1 of the bidirectional switch is connected with the end 1 of the primary coil of the transformer by being connected between the resonant inductor Lr and the resonant capacitor Cr, and the end 2 of the bidirectional switch is connected with the end 2 of the primary coil of the transformer;
the characteristic lies in that the resonance inductance Lr is connected between the 1 end of the two-way switch and the 1 end of the primary coil of the transformer, and the resonance capacitance Cr is connected between the 1 end of the two-way switch and the No. 1 output end of the inverter circuit.
2. The LLC resonant converter of claim 1, wherein said inverter circuit is a half-bridge inverter circuit.
3. The LLC resonant converter of claim 1, wherein the inverter circuit is a full bridge inverter circuit comprising four switching tubes S1, S2, S3 and S4, wherein the switching tubes S1 and S2 are respectively used for controlling whether the positive pole of the input power Vin is connected to the output terminals No. 1 and No. 2 of the inverter circuit, and the switching tubes S3 and S4 are respectively used for controlling whether the output terminals No. 1 and No. 2 of the inverter circuit is connected to the negative pole of the input power Vin.
4. The LLC resonant converter according to claim 3, wherein said bidirectional switch is formed by two switching tubes S5, S6 connected in series in opposite directions, wherein a parasitic diode pointing to a connection of said bidirectional switch with said resonant inductor Lr and resonant capacitor Cr is a switching tube S5.
5. The LLC resonant converter of claim 4, wherein said rectification network employs a full wave rectification architecture.
6. The LLC resonant converter of claim 5, wherein the rectifying network employs a full bridge rectifying structure, the full bridge rectifying structure being constituted by rectifying diodes or switching tubes.
7. A method of controlling an LLC resonant converter as claimed in any one of claims 1 to 6, wherein said LLC resonant converter is controlled using fixed frequency PWM.
8. A method for controlling an LLC resonant converter as claimed in any one of claims 4 to 6, wherein said LLC resonant converter is controlled using fixed frequency PWM.
9. The control method of claim 8, wherein switching frequencies of the switching tubes S1-S6 are equal and fixed, the switching tube S1 and the switching tube S5 are complementarily turned on, the switching tube S2 and the switching tube S6 are complementarily turned on, the switching tube S1 and the switching tube S4 are simultaneously turned on and off, the switching tube S2 and the switching tube S3 are simultaneously turned on and off, a duty ratio of the switching tube S1 is equal to a duty ratio of the switching tube S2, is not greater than 0.5 and has a phase difference of 180 degrees, a duty ratio of the switching tube S5 is equal to a duty ratio of the switching tube S6, is not less than 0.5 and has a phase difference of 180 degrees, the control of the output voltage is realized by adjusting the duty ratio of the switching tube S1, and the larger duty ratio of the switching tube S1 is, the gain of the output voltage is larger.
CN201910840399.7A 2019-09-06 2019-09-06 LLC resonant converter and control method Pending CN110707931A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CN201910840399.7A CN110707931A (en) 2019-09-06 2019-09-06 LLC resonant converter and control method
PCT/CN2020/092918 WO2021042773A1 (en) 2019-09-06 2020-05-28 Llc resonant converter and control method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201910840399.7A CN110707931A (en) 2019-09-06 2019-09-06 LLC resonant converter and control method

Publications (1)

Publication Number Publication Date
CN110707931A true CN110707931A (en) 2020-01-17

Family

ID=69194409

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201910840399.7A Pending CN110707931A (en) 2019-09-06 2019-09-06 LLC resonant converter and control method

Country Status (2)

Country Link
CN (1) CN110707931A (en)
WO (1) WO2021042773A1 (en)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110649812A (en) * 2019-09-06 2020-01-03 广州金升阳科技有限公司 Wide-gain-range LLC resonant converter and control method thereof
CN112083213A (en) * 2020-08-10 2020-12-15 广州金升阳科技有限公司 Converter, current detection circuit and current detection method
WO2021042773A1 (en) * 2019-09-06 2021-03-11 广州金升阳科技有限公司 Llc resonant converter and control method
CN112600415A (en) * 2020-12-01 2021-04-02 上海交通大学 Bidirectional resonant network, bidirectional direct current converter and parameter design method thereof
WO2021077757A1 (en) * 2019-10-22 2021-04-29 广州金升阳科技有限公司 Wide gain control method for variable topology llc resonant converter
CN113302828A (en) * 2020-10-16 2021-08-24 深圳欣锐科技股份有限公司 Voltage conversion circuit and electronic device
CN113572361A (en) * 2021-07-21 2021-10-29 中国科学院电工研究所先进电磁驱动技术研究院 Bidirectional DC converter, and control method, medium, and apparatus thereof
CN114257097A (en) * 2021-12-23 2022-03-29 湖南大学 Multi-mode switching wide-output direct current converter and switching control thereof
CN114285286A (en) * 2021-09-24 2022-04-05 中南大学 Single-stage zero-current switch full-bridge boost direct current converter and control method thereof
CN114583932A (en) * 2022-04-29 2022-06-03 茂睿芯（深圳）科技有限公司 Control circuit and control method for LLC resonant converter
CN115589159A (en) * 2022-12-09 2023-01-10 惠州市乐亿通科技有限公司 Bidirectional conversion circuit, multi-mode control method and bidirectional resonant converter
WO2023041019A1 (en) * 2021-09-18 2023-03-23 广州金升阳科技有限公司 Llc resonant converter and control method therefor
CN117277821A (en) * 2023-11-17 2023-12-22 湖南北顺源智能科技有限公司 Mixed type high-voltage direct-current electric energy converter system of submarine observation network and control method

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN201345619Y (en) * 2009-01-20 2009-11-11 华南理工大学 Low voltage stress single-stage AC-DC converter based on LLC serial connection resonance
CN102130600A (en) * 2011-03-28 2011-07-20 张家港华峰电接插元件有限公司 Serial resonant switching power supply
US20120268969A1 (en) * 2011-04-20 2012-10-25 Cuks, Llc Dc-ac inverter with high frequency isolation transformer
CN103595257A (en) * 2013-11-28 2014-02-19 南京航空航天大学 Isolation type direct-current buck converter with soft switching function and control method of isolation type direct-current buck converter
CN104011986A (en) * 2011-12-21 2014-08-27 伊顿工业公司 LLC bidirectional resonant converter and method of controlling
CN105811779A (en) * 2016-04-25 2016-07-27 天津大学 CLTC resonant soft switching bi-directional converter
CN206992959U (en) * 2017-05-17 2018-02-09 苏州汇川联合动力系统有限公司 Two-way resonance converter
CN108494260A (en) * 2018-04-11 2018-09-04 深圳市金威源科技股份有限公司 A kind of soft switch circuit
CN108696140A (en) * 2018-06-08 2018-10-23 山东大学 Full-bridge resonance DC-DC converter with wide output voltage range and modulator approach
US20190173388A1 (en) * 2017-12-05 2019-06-06 Abb Schweiz Ag Soft-switching power converters using air-core resonant inductor

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105048490B (en) * 2015-06-24 2017-07-25 江苏华盛电气股份有限公司 The photovoltaic micro-inverter and its numerical control device of low current stress
CN110649812B (en) * 2019-09-06 2021-12-10 广州金升阳科技有限公司 Wide-gain-range LLC resonant converter and control method thereof
CN110707931A (en) * 2019-09-06 2020-01-17 广州金升阳科技有限公司 LLC resonant converter and control method
CN110601543B (en) * 2019-09-11 2020-08-18 广州金升阳科技有限公司 Wide gain control method of LLC resonant converter and resonant converter thereof

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN201345619Y (en) * 2009-01-20 2009-11-11 华南理工大学 Low voltage stress single-stage AC-DC converter based on LLC serial connection resonance
CN102130600A (en) * 2011-03-28 2011-07-20 张家港华峰电接插元件有限公司 Serial resonant switching power supply
US20120268969A1 (en) * 2011-04-20 2012-10-25 Cuks, Llc Dc-ac inverter with high frequency isolation transformer
CN104011986A (en) * 2011-12-21 2014-08-27 伊顿工业公司 LLC bidirectional resonant converter and method of controlling
CN103595257A (en) * 2013-11-28 2014-02-19 南京航空航天大学 Isolation type direct-current buck converter with soft switching function and control method of isolation type direct-current buck converter
CN105811779A (en) * 2016-04-25 2016-07-27 天津大学 CLTC resonant soft switching bi-directional converter
CN206992959U (en) * 2017-05-17 2018-02-09 苏州汇川联合动力系统有限公司 Two-way resonance converter
US20190173388A1 (en) * 2017-12-05 2019-06-06 Abb Schweiz Ag Soft-switching power converters using air-core resonant inductor
CN108494260A (en) * 2018-04-11 2018-09-04 深圳市金威源科技股份有限公司 A kind of soft switch circuit
CN108696140A (en) * 2018-06-08 2018-10-23 山东大学 Full-bridge resonance DC-DC converter with wide output voltage range and modulator approach

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
JOÃO P. COIMBRA ; RENAN C. PONTARA ; LUIZ P. LOURES ; PEDRO S. A: "An isolated bidirectional soft-switching converter based on LLC resonant half-bridge with synchronous rectification", 《2017 BRAZILIAN POWER ELECTRONICS CONFERENCE (COBEP)》 *

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2021042773A1 (en) * 2019-09-06 2021-03-11 广州金升阳科技有限公司 Llc resonant converter and control method
CN110649812B (en) * 2019-09-06 2021-12-10 广州金升阳科技有限公司 Wide-gain-range LLC resonant converter and control method thereof
CN110649812A (en) * 2019-09-06 2020-01-03 广州金升阳科技有限公司 Wide-gain-range LLC resonant converter and control method thereof
WO2021077757A1 (en) * 2019-10-22 2021-04-29 广州金升阳科技有限公司 Wide gain control method for variable topology llc resonant converter
CN112083213A (en) * 2020-08-10 2020-12-15 广州金升阳科技有限公司 Converter, current detection circuit and current detection method
WO2022033239A1 (en) * 2020-08-10 2022-02-17 广州金升阳科技有限公司 Current detection circuit, converter, and current detection method for converter
WO2022077421A1 (en) * 2020-10-16 2022-04-21 深圳欣锐科技股份有限公司 Voltage conversion circuit and electronic device
CN113302828A (en) * 2020-10-16 2021-08-24 深圳欣锐科技股份有限公司 Voltage conversion circuit and electronic device
CN113302828B (en) * 2020-10-16 2023-11-17 深圳欣锐科技股份有限公司 Voltage conversion circuit and electronic device
CN112600415A (en) * 2020-12-01 2021-04-02 上海交通大学 Bidirectional resonant network, bidirectional direct current converter and parameter design method thereof
CN113572361A (en) * 2021-07-21 2021-10-29 中国科学院电工研究所先进电磁驱动技术研究院 Bidirectional DC converter, and control method, medium, and apparatus thereof
WO2023041019A1 (en) * 2021-09-18 2023-03-23 广州金升阳科技有限公司 Llc resonant converter and control method therefor
CN114285286A (en) * 2021-09-24 2022-04-05 中南大学 Single-stage zero-current switch full-bridge boost direct current converter and control method thereof
CN114285286B (en) * 2021-09-24 2023-09-01 中南大学 Single-stage zero-current switching full-bridge boost direct-current converter and control method thereof
CN114257097A (en) * 2021-12-23 2022-03-29 湖南大学 Multi-mode switching wide-output direct current converter and switching control thereof
CN114257097B (en) * 2021-12-23 2024-01-16 湖南大学 Wide-output direct-current converter with multi-mode switching and switching control thereof
CN114583932A (en) * 2022-04-29 2022-06-03 茂睿芯（深圳）科技有限公司 Control circuit and control method for LLC resonant converter
CN115589159A (en) * 2022-12-09 2023-01-10 惠州市乐亿通科技有限公司 Bidirectional conversion circuit, multi-mode control method and bidirectional resonant converter
CN115589159B (en) * 2022-12-09 2023-03-14 惠州市乐亿通科技有限公司 Bidirectional conversion circuit, multi-mode control method and bidirectional resonant converter
CN117277821A (en) * 2023-11-17 2023-12-22 湖南北顺源智能科技有限公司 Mixed type high-voltage direct-current electric energy converter system of submarine observation network and control method
CN117277821B (en) * 2023-11-17 2024-02-06 湖南北顺源智能科技有限公司 Mixed type high-voltage direct-current electric energy converter system of submarine observation network and control method

Also Published As

Publication number Publication date
WO2021042773A1 (en) 2021-03-11

Similar Documents

Publication Publication Date Title
CN110649812B (en) Wide-gain-range LLC resonant converter and control method thereof
CN110707931A (en) LLC resonant converter and control method
CN110768535B (en) Wide gain control method of variable topology LLC resonant converter
US11496054B2 (en) High-gain quasi-resonant DC-DC converter based on voltage doubling rectifier circuit
CN109217681B (en) Bidirectional resonant converter
US6246599B1 (en) Constant frequency resonant inverters with a pair of resonant inductors
CN110601543B (en) Wide gain control method of LLC resonant converter and resonant converter thereof
CN112054691B (en) Single-stage voltage-regulating conversion circuit sharing rectification structure and control method
CN111181408A (en) Resonant converter based on hybrid rectification structure and control method
CN112332674A (en) LLC resonant converter and wide gain control method
CN110190752B (en) Bidirectional CLLLC-DCX resonant converter and control method thereof
CN114301301A (en) Wide-range resonant soft-switching bidirectional direct-current converter and control method thereof
CN110165895B (en) Circuit structure and control method for realizing wide-gain FB-HB LLC resonant converter
CN111431415B (en) High-boost isolated DC converter with parallel input and series output
CN114301300A (en) Wide-range bidirectional resonant soft-switching direct-current converter and control method thereof
CN114337344A (en) Control method based on self-adaptive hybrid rectification multi-switch resonant LLC converter
CN114465490A (en) Interleaved voltage-multiplying wide-output LLC resonant converter and control method thereof
CN217087777U (en) Wide-range resonant soft-switching bidirectional direct-current converter
CN109698627B (en) Full-bridge DC/DC converter based on switched capacitor and modulation strategy thereof
CN114640255A (en) Series resonant converter and control method thereof
CN109742957B (en) Double-ring full-resonance type soft switching converter
Han et al. A new full-bridge converter with phase-shifted coupled inductor rectifier
CN115441746A (en) Direct current converter topological structure with adjustable output voltage in wide input range
CN114900048A (en) Three-phase bidirectional DC-DC converter
CN209982343U (en) Circuit structure for realizing wide-gain FB-HB LLC resonant converter

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
RJ01 Rejection of invention patent application after publication
RJ01 Rejection of invention patent application after publication

Application publication date: 20200117