JP2019009848A - Dc-dc converter, power supply system employing the same, and automobile employing the power supply system - Google Patents

Abstract

To provide a DC-DC converter capable of suppressing output voltage fluctuation while performing dead time change control for reducing a switching loss of the DC-DC converter, and a power supply system with the same.SOLUTION: A power conversion device comprises an input terminal, an output terminal, multiple semiconductor switching elements, and a control circuit which controls dead times among the multiple switching elements. A DC-DC converter is characterized in that, in a power supply system where a device that is different from the DC-DC converter is present, at least one dead time among the multiple switching elements can be changed based on operation information of the device that is different from the DC-DC converter.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power conversion device, and more particularly, to a power supply system using a dead time set between a series of pulses for driving on / off of a semiconductor switch element and a vehicle using the power supply system.

  In recent years, against the background of depletion of fossil fuels and the deterioration of global environmental problems, interest in automobiles using electric energy, such as hybrid cars and electric cars, has increased and has been put to practical use.

  An automobile using such electric energy is provided with a power conversion device that steps down a high-voltage battery voltage for supplying power to a motor for driving wheels and supplies necessary power to a low-voltage electric device. There are many cases. Examples of such low-voltage electrical devices include air conditioners, audios, and automobile controllers. In general, a DC-DC converter is used for a power conversion device that supplies power from a high-voltage battery to a low-voltage electric device.

  The DC-DC converter is provided with a plurality of semiconductor switch elements. The semiconductor switch element includes, for example, a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), an IGBT (Insulated Gate Bipolar Transistor), or the like. In the DC-DC converter, power conversion is performed by controlling on / off of a switching circuit constituted by these semiconductor switch elements. A typical DC-DC converter converts a direct current input into alternating current using a switching circuit, then transforms the voltage using a transformer (step-up or step-down), and further uses an output circuit such as a rectifier circuit. It is a device that converts this to DC again. As a result, a DC output having a voltage different from the input voltage can be obtained. Here, as a switching circuit requiring a large capacity, a so-called full-bridge type switching circuit is generally used. However, as a driving method capable of reducing switching loss generated in this type of semiconductor switching element. A phase shift control method is known.

  In the phase shift control method, the phase of the upper switch element of one leg and the lower switch element of the other leg of the four switch elements constituting the full bridge type switching circuit (the lower switch element and the other leg of one leg). The same applies to the phase of the upper switch element of one leg) according to the output voltage, so that the upper switch element of one leg and the lower switch element of the other leg are simultaneously turned on, The period during which the lower switch element of the second leg and the upper switch element of the other leg are simultaneously turned on is adjusted according to the output voltage. Here, the power transmitted from the switching circuit (primary side of the transformer) to the output circuit (secondary side of the transformer) is such that the upper switch element of one leg and the lower switch element of the other leg are simultaneously turned on. And the period in which the lower switch element of one leg and the upper switch element of the other leg are simultaneously turned on, the output voltage is stabilized at a desired value by controlling the phase. It becomes possible.

  However, in order to stably set the output voltage to a desired value, a voltage controller having a high response to the load current fluctuation of the DC-DC converter is required. The amount of current varies depending on the usage conditions. At that time, if the fluctuation of the output voltage of the DC-DC converter is large due to the fluctuation of the negative overcurrent or the like, there is a possibility of affecting a device different from the DC-DC converter connected in parallel as the load of the DC-DC converter. is there. Therefore, the DC-DC converter requires a highly responsive voltage controller to suppress the output voltage fluctuation even when the negative overcurrent fluctuation is large.

  The plurality of switch elements of the switching circuit are provided separately on the upper side of the leg and the lower side of the leg, and the switch element on the upper side of the leg and the switch element on the lower side of the leg are connected in series. At this time, if the switch element on the upper side of the legs connected in series and the switch element on the lower side of the leg are turned on at the same time, a leg short circuit may occur and an overcurrent may flow. Therefore, of the two switch elements belonging to the same leg, the on-period of one switch element and the other switch element of the other leg are prevented so that the switch element on the upper side of the leg and the switch element on the lower side of the leg are not simultaneously turned on. It is necessary to provide a period in which both of these two switch elements are in the off state between the on period. Such a period is called dead time.

Further, in the switching circuit based on the phase shift control method, the capacitance components of the four switching elements and / or the capacitance components of the capacitance elements added to the respective switching elements and the resonance inductance (for example, resonance coil or transformer leakage inductance) are used. A resonance circuit is formed, and the switching loss is reduced by using the resonance characteristics to turn on the voltage of these semiconductor switch elements close to zero. The resonance circuit performs resonance operation during a period from when one switch element belonging to the same leg is turned off to when the other switch element is turned on, that is, a dead time, and thereby four switch elements constituting the switching circuit. The turn-on loss is reduced. Thus, the dead time is also used as a resonance period for reducing the turn-on loss in the switching circuit based on the phase shift control method.
Therefore, it is necessary to determine how long the dead time is set in consideration of the resonance characteristics of the resonance circuit. The resonance characteristics of the resonance circuit vary depending on the input voltage and output current of the DC-DC converter. Specifically, the longer the input voltage is, and the smaller the output current is, the longer the time required for resonance.

  Therefore, as a means for solving such a problem, there is JP-A-2006-1111776 (Patent Document 1). This is a power conversion that changes the ratio of the dead time to the switching period according to the current value so that the dead time decreases according to the increase in the load current of the DC-DC converter by the control circuit that controls the switching circuit. An apparatus is disclosed.

Japanese Patent Laid-Open No. 2006-1111776

  By the way, the power converter described in Patent Document 1 described above introduces dead time into the inner loop of the voltage controller that controls the output voltage of the DC-DC converter by introducing control of dead time change according to current increase. It is necessary to add a current controller for change. For stable operation of the control circuit, it is necessary to set the response time constant of the voltage controller arranged in the outer loop sufficiently slower than the response time constant of the current controller that is the inner loop. However, when the response time constant of the voltage controller is delayed, there is a problem that the response of the output voltage fluctuation to the negative overcurrent fluctuation of the DC-DC converter is lowered.

  The objective of this invention is providing the DC-DC converter which can suppress an output voltage variation, and a power supply system provided with the same, performing dead time change control which reduces the switching loss of a DC-DC converter.

  A power conversion device according to the present invention is a power conversion device that includes a plurality of semiconductor switch elements and a control circuit that controls a dead time between the plurality of switch elements, and is mounted on a vehicle. This is achieved by a power conversion device that controls a dead time between the plurality of switching elements based on operation information of a device that is mounted and different from the power conversion device.

  Note that the operation information includes the drive / stop state of the device, input / output voltage, input / output current, and the like.

  In addition, the different device is a device connected in parallel to the input terminal of the power conversion device or via a battery (for example, an inverter for driving a vehicle or an in-vehicle charger), or an output terminal of the power conversion device. A device connected in parallel or via a battery (for example, an air conditioner, audio, coolant pump, battery, etc.) or a vehicle electronic control unit.

  According to the present invention, the dead time is variable and the DC-DC converter can be used without adding a current controller for changing the dead time to the inner loop of the voltage controller that controls the output voltage of the DC-DC converter. Since the dead time is varied according to the operation information of different devices, the output voltage of the DC-DC converter can be stably set to a desired value while reducing the switching loss.

  The operation information preferably changes a dead time between the plurality of switching elements based on operation information from a plurality of devices.

  In addition, the control circuit increases the dead time between the plurality of switching elements as the voltage of a device connected in parallel and / or via a battery to the input terminal of the power converter in the different device increases. It is also preferable.

  In addition, the control circuit may be configured such that the smaller the number of drives and / or the smaller the current connected to the output terminals of the power converters in the different devices, the smaller the current between the plurality of switching elements. It is also preferable to increase the dead time.

  In addition, the control circuit may reduce the dead between the plurality of switching elements as the number of devices connected to the output terminal of the power conversion device in the different device or the number of devices connected via a battery decreases. It is also preferable to increase the time.

  Further, when the control circuit is set with a maximum dead time value and the dead time value calculated by the control circuit is larger than the maximum dead time value, the control circuit dead time output is output to the maximum dead time value. It is also preferable to use a value. Further, when the control circuit is set with a minimum dead time value and the dead time value calculated by the control circuit is smaller than the minimum dead time value, the control circuit outputs the dead time output of the control circuit. It is also preferable that

It is a circuit block diagram of the bidirectional | two-way DC-DC converter by Example 1 of this invention. 3 is a circuit block diagram showing configurations of a voltage control unit 70 and a dead time setting unit 80 in a control circuit 40 that performs phase shift control. FIG. It is a table | surface which shows the relationship between the drive / stop state of load R2, and a dead time. It is a table | surface which shows the relationship between the drive / stop state of several load R2, and a dead time. It is a figure which shows the relationship between the voltage state of load R1, and a dead time. It is a figure which shows the relationship between the electric current state of load R1 and load R2, and dead time. It is explanatory drawing of the output signal calculation method of the DC-DC converter 200 which concerns on this embodiment. It is a figure which shows the change of the output current and output voltage explaining the effect of this embodiment. It is a circuit block diagram of the bidirectional | two-way DC-DC converter by Example 2 of this invention. The present invention relates to an in-vehicle power supply system using a DC-DC converter 200 according to the second embodiment. It is a block block diagram at the time of applying to the motor vehicle 1000 as a power supply system.

  Hereinafter, an embodiment of a power conversion device according to the present invention will be described with reference to the drawings. In addition, in each figure, the same code | symbol is described about the same element and the overlapping description is abbreviate | omitted. The present invention is not limited to the following embodiments, and includes various modifications and application examples within the scope of the technical concept of the present invention.

(First embodiment)
(Main circuit configuration)
FIG. 1 is a circuit configuration diagram of a bidirectional DC-DC converter according to Embodiment 1 of the present invention.

  The power conversion device according to the present embodiment transforms the input voltage Vin applied between the input terminal 1 and the input terminal 2 to generate the output voltage Vout, and supplies this to the output terminal 3 and the output terminal 4. Device.

  The power converter according to the present embodiment is connected between the transformer 20, the switching circuit 10 connected between the transformer 20 and the input terminals 1 and 2, and the transformer 20 and the output terminals 3 and 4. And an output circuit 30 and a control circuit 40 for controlling the switching circuit 10.

  At the time of implementation, a DC power supply V1 and a load R1 driven by the DC power supply V1 are connected between the input terminal 1 and the input terminal 2. Between the output terminal 3 and the output terminal 4, a DC power source V2 and a load R2 driven by the DC power source V2 are connected. Here, the load R1 and the load R2 are an auxiliary machine such as a vehicle driving motor or a power steering device.

  A capacitor C1 that stabilizes the input voltage Vin is connected between the input terminal 1 and the input terminal 2, but may be connected to the DC power supply V1 side as viewed from the input terminals 1 and 2. The same applies to the capacitor C2 connected to the output terminals 3 and 4.

(Switching circuit 10)
The switching circuit 10 converts the input voltage Vin applied to the input terminal 1 and the input terminal 2 into an alternating current and supplies it to the primary winding N1 of the transformer 20, and in this embodiment, four switching elements 11a. 14a is configured to be connected by a full bridge. One input connection point of the switching circuit 10 is connected to the input terminal 1 and the input terminal 2, and the other output connection point of the switching circuit 10 is connected to both ends of the primary winding N <b> 1 of the transformer 20.

  The detailed configuration of the switching circuit 10 includes a switch element 11a and a switch element 12a connected in series to the input terminal 1 and the input terminal 2, a connection point A between the switch element 11a and the switch element 12a, and the input terminal 1 and the input terminal 2 as well. Switch element 13a and switch element 14a connected in series, and connection point B of switch element 13a and switch element 14a.

  The connection point A is connected to one of the primary windings N1, and the connection point B is connected to the other of the primary windings N1. As the switch elements 11a to 14a, known switch elements can be used, but FETs (field effect transistors) are preferably used.

  Diodes 11b to 14b and capacitors 11c to 14c are connected in parallel to the switch elements 11a to 14a, respectively. These diodes 11b to 14b and capacitors 11c to 14c may be separate solids from the switch elements 11a to 14a, or may be parasitic components of the switch elements 11a to 14a. Further, the parasitic components of the switch elements 11a to 14a may be used in combination with another solid diode and capacitor.

(Transformer 20)
The transformer 20 according to the present embodiment has a center tap configuration, and includes a primary winding N1, a secondary winding N2a, and a secondary winding N2b. The turns ratio of the primary winding N1 and the secondary winding N2a or the turns ratio of the primary winding N1 and the secondary winding N2b is set according to the voltage range of the input voltage Vin and the voltage range of the output voltage Vout. .

  The transformer 20 is provided with a resonance inductance L1 in series with the primary winding N1. A resonance circuit that reduces switching loss generated in the switching circuit 10 is formed by the capacitance components of the switch elements 11a to 14a and / or the capacitance components of the capacitors 11c to 14c added to the switch elements 11a to 14a and the resonance inductance L1. Is done. When the value of the resonance inductance L1 of the transformer 20 is small, another inductance may be connected in series with the resonance inductance L1 to increase the inductance value.

  In the description of the present embodiment, a series circuit including the switch element 11a and the switch element 12a is referred to as a “first leg”, and a series circuit including the switch element 13a and the switch element 14a is referred to as a “second leg”. The connection point A, which is the midpoint of the first leg, is connected to one of the primary windings N1 of the transformer 20 via the resonance inductance L1, and the connection point B, which is the midpoint of the second leg, is connected to the transformer 20 Is connected to the other primary winding N1.

(Output circuit 30)
The output circuit 30 according to the present embodiment smoothes and rectifies the AC voltage appearing in the secondary windings N2a and N2b of the transformer 20 to generate an output voltage Vout that is a DC voltage, and this output voltage Vout is output to the output terminal 3. And between the output terminals 4.

  The diode 31 is connected between one of the secondary windings N2a of the transformer 20 and the rectifying connection point S. The diode 32 is connected between one of the secondary windings N2b of the transformer 20 and the rectifying connection point S.

  The neutral point T is a connection point between the other secondary winding N2a of the transformer 20 and the other secondary winding N2b of the transformer 20. The smoothing coil L <b> 2 is connected between the neutral point T and the output terminal 3. The capacitor C <b> 2 is connected between the output terminal 3 and the output terminal 4. The voltage detection circuit 51 detects the output voltage between the output terminal 3 and the output terminal 4.

  In the output circuit 30 having such a configuration, the diodes 31 and 32 constitute a rectifier circuit that rectifies the AC voltage appearing from the secondary winding N2a and the secondary winding N2b of the transformer 20. Smoothing coil L2 and capacitor C2 constitute a smoothing circuit that smoothes the rectified output generated at neutral point T. The diodes 31 and 32 may be replaced with FETs or the like, and a synchronous rectification operation, which is a well-known technique with small conduction loss, may be performed.

(Control circuit 40)
The control circuit 40 according to this embodiment is a circuit that controls the operation of the switching circuit 10 so that the output voltage Vout applied across the capacitor C2 becomes a predetermined target value. As shown in FIG. 1, the control circuit 40 includes a voltage control unit 70 and a dead time setting unit 80. In the description of the present embodiment, the predetermined target value is referred to as “command value Vref”.

  Based on the output voltage Vout detected by the voltage detection circuit 51 and the command value Vref, the control circuit 40 generates output signals 41 to 44 for performing the phase shift control method in the voltage control unit 70. The generated output signals 41 to 44 generate drive signals 61 to 64 for driving the switch elements 11a to 14a by the insulating circuit 60, and the drive signals 61 to 64 are supplied to the control electrodes of the switch elements 11a to 14a. .

  The control circuit 40 is connected between the voltage value VR1 of the load R1 connected between the input terminal 1 and the input terminal 2 and / or the current value IR1 flowing through the load R1 and / or between the output terminal 3 and the output terminal 4. Based on the current value IR2 of the load R2, the dead times of 41 to 44 that are output signals of the switch elements 11a to 14a are controlled.

  FIG. 2 is a circuit block diagram showing the configuration of the voltage control unit 70 and the dead time setting unit 80 in the control circuit 40 that performs phase shift control.

  As shown in FIG. 2, the control circuit 40 includes a subtraction unit 71, a PI control unit 72, a duty limiting unit 77, a pulse generation setting unit 78, an output signal generation unit 79, a dead time setting unit 80, a triangular wave And a signal device 91.

  Further, the PI control unit 72 includes a proportional unit 73, a proportional unit 74, an integrating unit 75, and an adding unit 76. The dead time setting unit 80 includes a dead time selection unit 81 and a dead time restriction unit 82.

  The operation of the control circuit 40 will be described.

  The subtraction unit 71 subtracts the difference between the command value Vref and the output voltage Vout detected by the voltage detection circuit 51, and calculates the difference voltage 101 between them. The command value Vref is an arbitrary command voltage value of the DC-DC converter 200 shown in FIG. 1, and may be set in advance in the DC-DC converter 200, and is changed according to a command value from the outside. You may do it.

  The differential voltage 101 is input to the PI control unit 72. In the PI control unit 72, the proportional units 73 and 74, the integration unit 75, and the addition unit 76 calculate the duty value 102 necessary for the phase shift control.

  The duty value 102 is input to the duty restriction unit 77. The duty limiter 77 is provided with a preset maximum duty value Duty_max and minimum duty value Duty_min. Note that the maximum duty value Duty_max and the minimum duty value Duty_min are not constant values, but may be changed by an external command value.

  As shown in the duty restriction unit 77 of FIG. 2, the duty value 102 output from the PI control unit 72 is compared with the maximum duty value Duty_max and the minimum duty value Duty_min, and the duty value 102 exceeds the maximum duty value Duty_max. In this case, the limiting unit output duty value 103 is set to Duty_max, and when the duty value 102 is lower than the minimum duty value Duty_min, the limiting unit output duty value 103 is set to Duty_min.

  The following relational expression is established for the limiting unit output duty value, the maximum duty value Duty_max, and the minimum duty value Duty_min. The duty value is an on-time ratio per cycle.

Duty_min ≤ Duty value ≤ Duty_max ... number (1)
The pulse generation setting unit 78 outputs a pulse generation signal 106 for realizing phase shift control based on the limiting unit output duty value 103 from the duty limiting unit 77 and the dead time output signal 104.

(Explanation of dead time setting method)
Here, a method for generating the dead time output signal 104 will be described with reference to FIGS.

  The dead time selection unit 81 shown in FIG. 2 includes a driving / stopped state of the load R1, which is a device different from the DC-DC converter 200, a voltage VR1 value applied to the load R1, and a current value flowing through the load R1. IR1 or a current value proportional thereto, a drive / stop state of a load R2, which is a device different from the DC-DC converter 200, a voltage value VR2 applied to the load R2, and a current value IR2 flowing through the load R2 or proportional thereto At least one piece of information among the current values to be input is input.

  The dead time selection unit 81 outputs a dead time setting signal 105 corresponding to the input information by using the input information and the dead time setting table shown in FIG. 3A or 3B.

  The dead time setting table shown in FIGS. 3A and 3B will be described. As a calculation method of the dead time setting signal 105, there are the following methods (1) to (3), for example. Therefore, the dead time setting signal 105 may be calculated using any one of these methods. A plurality of these methods may be used. Furthermore, the information on the loads R1 and R2 is not limited to one, and information from a plurality of loads may be used. However, these are merely examples, and the dead time setting signal 105 may be obtained by information on a device different from the other DC-DC converter 200 and other methods using the information.

  (1) As shown in FIG. 3A, the dead time setting table 1 showing the relationship between the driving / stopped state of the load R2 and the dead time is used. Specifically, when the load R2 is in the driving state, the dead time setting signal 105 is Dd_a, and when the load R2 is in the stop state, the dead time setting signal 105 is Dd_b. Note that the magnitude relationship between Dd_a and Dd_b is preferably set to be smaller than Dd_b because the resonance time during the dead time period of the switching circuit 10 may be short when the load R2 is driven. Further, as shown in FIG. 3B, the dead time setting signal 105 is determined by the dead time setting table 2 indicating the relationship between the driving / stopped states of the plurality of loads R2-1 to R2-4 and the dead time. Also good. For example, when the load R2-1 is driven (ON), the load R2-2 is stopped (OFF), the load R2-3 is stopped (OFF), and the load R2-4 is stopped (OFF), the dead time setting signal 105 is Let Dd_c. In addition, since Dd_d to Dd_g in the dead time setting signal 105 can be determined according to FIG. Although the dead time setting unit 81 based on the information on the loads R2-1 to R2-4 has been described, the present embodiment can be applied even if the number of loads is changed.

  (2) As shown in FIG. 3C, the dead time setting signal 105 is determined based on the current value IR1 of the load R1 and / or the current value IR2 of the load R2. In the dead time setting unit 81, a dead time setting table 3 indicating the relationship between the current value IR1 of the load R1 and / or the current value IR2 of the load R2 and the dead time setting signal 105 is set in advance. When the current value IR1 of the load R1 and / or the current value IR2 of the load R2 is large, the resonance time during the dead time period of the switching circuit 10 may be short. Therefore, it is preferable to make the dead time setting signal 105 small. Further, as shown in FIG. 3C, the value of the dead time setting table may be changed based on the driving / stopping state of the load R1 or the load R2. FIG. 3C shows the relationship between the current value IR1 of the load R1 and / or the current value IR2 of the load R2 and the dead time setting signal 105 as a proportional function, but other functions, inflection points, There may be no function continuity.

  (3) As shown in FIG. 3D, the dead time setting signal 105 is determined based on the voltage value VR1 of the load R1. In the dead time setting unit 81, a dead time setting table 4 indicating the relationship between the voltage value VR1 of the load R1 and the dead time setting signal 105 is set in advance. When the voltage value VR1 of the load R1 is small, the resonance time during the dead time period of the switching circuit 10 may be short. Therefore, it is preferable to make the dead time setting signal 105 small. FIG. 3D shows the relationship between the voltage value VR1 of the load R1 and the dead time setting signal 105 as a proportional function. However, other functions may be used, and continuity such as a function having an inflection point may be used. You may use a function without.

  Thus, for example, the dead time setting signal 105 can be obtained in the dead time selection unit 81 by using the calculation methods (1) to (3) described above.

  Subsequently, the dead time setting signal 105 is input to the dead time limiter 82. In the dead time limiting unit 82, a preset maximum dead time value Dd_max and a minimum dead time value Dd_min are provided. Note that the maximum dead time value Dd_max and the minimum dead time value Dd_min do not have to be constant values, and may be changed according to an external command value. The dead time setting signal 105 output from the dead time selection unit 81 shown in FIGS. 3A to 3D is compared with the maximum dead time value Dd_max and the minimum dead time value Dd_min, and the dead time setting signal 105 is compared. Exceeds the maximum dead time value Dd_max, the dead time output signal 104 is set to the maximum dead time value Dd_max. When the dead time setting signal 105 falls below the minimum dead time value Dd_min, the dead time output signal 104 is Let Dd_min.

  The following number (2) holds for the dead time output signal 104, the maximum dead time value Dd_max, and the minimum dead time value Dd_min. The dead time output signal 10 is a dead time time ratio per cycle.

Dd_min ≦ (dead time output signal 104) ≦ Dd_max (2)
As described above, the dead time setting unit 80 can output the dead time output signal 104. In the above description, the dead times of the first leg, which is a series circuit composed of the switch elements 11a and 12a, of the switching circuit 10 and the second leg, which is a series circuit composed of the switch elements 13a and 14a, are made equal. Although the calculation method for setting the dead time is described, the dead time output signal 104 may be changed so that the dead times of the first leg and the second leg are different. For example, let Dd_12 be the dead time output signal 104 in the first leg that is a series circuit composed of the switch element 11a and the switch element 12a, and dead time output signal 104 in the second leg that is a series circuit composed of the switch element 11a and the switch element 12a. May be Dd_34.

(Description of pulse generation setting unit 78)
A method for generating the pulse generation signal 106 in the pulse generation setting unit 78 will be described.

  The pulse generation setting unit 78 receives the limiting unit output duty value 103 calculated by the duty limiting unit 77 and the dead time output signal 104 calculated by the dead time limiting unit 82. In accordance with the input signal, a pulse generation signal 106 for driving the switch elements 11a to 14a of the switching circuit 10 is calculated.

  FIG. 4 is an explanatory diagram of an output signal calculation method of the DC-DC converter 200 according to the present embodiment. As the pulse generation signal 106, on-timing threshold signals 41a to 44a and off-timing threshold values 41b to 44b for determining the on / off timings of the switch elements 11a to 14a are output.

  The off timing threshold values 41 b to 44 b are set by the limiting unit output duty value 103. The on-timing threshold signals 41 a to 44 a are set by the limiter output duty value 103 and the dead time output signal 104. For example, when the limiter output duty value 103 is D, the dead time output signal 104 in the first leg is Dd_12, and the dead time output signal 104 in the second leg is Dd_34, the on-timing threshold signal 41a to 44a and the off-timing threshold signal 41b to 44b is as follows.

The on-timing threshold signal 41a is 1, 42a is 0.5, 43a is D + Dd_34, and 44a is D + 0.5 + Dd_34.
The off timing threshold 41b is 0.5-Dd_12, 42b is 1-Dd_12, 43b is D + 0.5, and 44b is D.

  However, the above is an example, and the on-timing threshold signals 41 a to 44 a and the off-time are based on the limiting unit output duty value 103 calculated by the duty limiting unit 77 and the dead time output signal 104 calculated by the dead time limiting unit 82. The timing threshold values 41b to 44b may be set. In this manner, the pulse generation setting unit 78 outputs the on-timing threshold signals 41a to 44a and the off-timing thresholds 41b to 44b in the pulse generation signal 106.

(Description of output signal generator 79)
The output signal generation unit 79 generates output signals 41 to 44 based on the pulse generation signal 106 from the pulse generation setting unit 78 and the triangular wave 92 from the triangular wave signal device 91.

  The operation of the output signal generator 79 will be described with reference to FIG. The triangular wave signal device 91 outputs a triangular wave 92 according to an arbitrary triangular wave frequency. The triangular wave frequency may be changed based on an external command value. Note that the triangular wave 92 does not have to be a triangular wave and may be any signal waveform that can be compared with the pulse generation signal 105.

  The output signal generation unit 79 includes an on timing threshold signal 41a to 44a and an off timing threshold for determining the on / off timing of each switch element 11a to 14a in the pulse generation signal 106 output from the pulse signal setting unit 78. 41b to 44b and the triangular wave 92 output from the triangular wave signal device 91 are input.

  The output signal generator 79 compares the triangular wave 92 with the on-timing threshold signals 41a to 44a and the off-timing threshold values 41b to 44b, and outputs output signals 41 to 44 that set the on / off timing of the switch elements. That is, the output signals 41 to 44 are switched on / off at the timing when the value of the triangular wave 92 reaches the on timing threshold signals 41a to 44a and the off timing thresholds 41b to 44b. Specifically, the output signal 41 is turned on at the timing when the value of the triangular wave 92 reaches the on-timing threshold signal 41a.

  Also, the output signal 41 is turned off at the timing when the value of the triangular wave 92 reaches the off timing threshold signal 41b.

  Further, the output signal 42 is turned on at the timing when the value of the triangular wave 92 reaches the on-timing threshold signal 42a.

  Also, the output signal 42 is turned off at the timing when the value of the triangular wave 92 reaches the off timing threshold signal 42b.

  The output signal 43 is turned on at the timing when the value of the triangular wave 92 reaches the on-timing threshold signal 43a.

  Further, the output signal 43 is turned off at the timing when the value of the triangular wave 92 reaches the off timing threshold signal 43b.

  The output signal 44 is turned on at the timing when the value of the triangular wave 92 reaches the on-timing threshold signal 44a.

  Further, the output signal 44 is turned off at the timing when the value of the triangular wave 92 reaches the off timing threshold signal 44b.

  As described above, the output signals 41 to 44 for setting the on / off timing of the switch elements 11a to 14a are generated by the pulse generation signal 106 output from the pulse signal setting unit 78 and the triangular wave 92 from the triangular wave signal device 91. Is done.

  The output signals 41 to 44 calculated by the output signal generation unit 79 are input to the insulation circuit 60. The insulation circuit 60 electrically insulates the control circuit 40 and the switching circuit 10, generates output signals 41 to 44 and drive signals 61 to 64 for driving the switch elements 11 a to 14 a, and switches elements 11 a to 14 a. To the control electrode.

  As described above, in the DC-DC converter 200 according to the present embodiment, the dead time is controlled based on information on a device different from that of the DC-DC converter 200, and thus the output voltage of the DC-DC converter 200 is controlled. By performing voltage control without adding a current controller for changing dead time to the inner loop of the voltage controller, the output voltage of the DC-DC converter 200 can operate stably.

  FIG. 5 is a diagram showing the effect of the present embodiment. When the output current of the DC-DC converter 200 changes from 50 A to 200 A, a case where a current controller for changing the dead time is inserted in the inner loop, The fluctuation | variation of the output voltage of the DC-DC converter 200 at the time of performing the dead time control in embodiment is shown.

  As shown in FIG. 5, the fluctuation of the output voltage of the DC-DC converter 200 in the present embodiment is such that the undershoot is small and the period until the output voltage is stabilized is shortened. There was an improvement.

(Effect of Example)
As described above, according to this embodiment, the dead time can be controlled by a device different from the DC-DC converter, and the dead loop is set in the inner loop of the voltage controller that controls the output voltage of the DC-DC converter. Without adding a current controller for changing the time, the dead time can be changed according to the operating information of the equipment different from the DC-DC converter, so the output voltage of the DC-DC converter can be stabilized while reducing the switching loss. It is possible to obtain a desired value.

(Second Embodiment)
FIG. 6 is a circuit configuration diagram of a bidirectional DC-DC converter according to Embodiment 2 of the present invention.

  The switching circuit 10, the transformer 20, and the output circuit 30 are the same as those in the first embodiment. In the control circuit 40, the dead time setting unit 80 is deleted from the dead time setting unit 80, and a vehicle power source control unit 300 different from the control circuit 40 of the DC-DC converter 200 is provided.

  FIG. 7 relates to an in-vehicle power supply system using the DC-DC converter 200 according to the second embodiment. The low voltage side of the DC-DC converter 200 is the E side, and the high voltage side is the F side.

  In the configuration of the power supply system, one end of the low-voltage battery V2 is connected to one end on the E side of the DC-DC converter 200, and the other end of the low-voltage battery V2 is connected to the other end on the E side of the DC-DC converter 200. . One end of auxiliary equipment 500 such as an air conditioner is connected to one end on the E side of DC-DC converter 200, and the other end of auxiliary equipment 500 is connected to the other end on the E side of DC-DC converter 200. One end of the HV system device 400 is connected to one end on the F side of the DC-DC converter 200, and the other end of the HV system device 400 is connected to the other end on the F side of the DC-DC converter 200. One end of the high-voltage battery V1 is connected to one end on the F side of the DC-DC converter 200, and the other end of the high-voltage battery V1 is connected to the other end on the F side of the DC-DC converter 200 via the relay 600. . The vehicle power supply control unit 300 controls the switching operation of each device including the DC-DC converter 200, the power transmission direction, the amount of power, and the dead time output signal 105. Note that the relay 800 may be omitted.

  FIG. 8 is a block configuration diagram when the present invention is applied to an automobile 1000 as a power supply system.

  The load R1, which is a device different from the DC-DC converter 200, is mainly an HV system device 400 and a charger 600 in the vehicle configuration diagram. For example, an inverter for driving a vehicle, an in-vehicle charger, a quick charger, and driving of the vehicle An inverter that supplies power to a motor that generates force, a pump that circulates coolant, and the like. The load R2, which is a device different from the DC-DC converter, is mainly the auxiliary equipment 500 in the vehicle configuration diagram, and is, for example, an air conditioner, an audio, an automobile controller, an electric brake, or the like. The loads R1 and R2 are not limited to the above, and may be any device that can drive / stop or detect current or voltage.

(Vehicle power supply control unit 300)
The vehicle power supply control unit 300 includes a drive / stop state of a load R1, which is a device different from the DC-DC converter, a voltage VR1 value applied to the load R1, which is a device different from the DC-DC converter, and a DC-DC The current value IR1 flowing through the load R1, which is a device different from the converter, or a current value proportional thereto, the drive / stop state of the load R2, which is a device different from the DC-DC converter, and a device different from the DC-DC converter At least one piece of information is input between a voltage value VR2 applied to a certain load R2 and a current value IR2 flowing through the load R2, which is a device different from the DC-DC converter, or a current value proportional thereto. The vehicle power supply control unit 300 outputs a dead time output signal 105 corresponding to the input information by using the input information and the dead time setting table shown in FIG.

  Subsequently, the dead time setting signal 105 is input to the dead time limiter 82. Subsequent operations are the same as those in the first embodiment, and a description thereof will be omitted.

  As described above, by deleting the dead time setting unit 81 from the control circuit 40 of the DC-DC converter 200, it is possible to reduce the dead time control processing inside the DC-DC converter 200.

(Effect of Example)
As described above, according to the present invention, the dead time can be controlled by a device different from the DC-DC converter, and the dead time is set in the inner loop of the voltage controller that controls the output voltage of the DC-DC converter. Without adding a current controller for change, the dead time can be changed according to the operation information of the equipment different from the DC-DC converter, so that the output voltage of the DC-DC converter can be stably desired while reducing the switching loss. The value can be Further, by performing the dead time variable control outside the DC-DC converter, the dead time control processing time inside the DC-DC converter can be reduced.

  In the present embodiment, the case where the present invention is applied to an automobile as an example of the power supply system is illustrated, but application to other power supply systems is also possible.

  As described above, in Example 1 and Example 22 of the present invention, a combination of a voltage-type full bridge circuit and a current-type center tap circuit is used. However, in a circuit configuration that uses other dead time, the same configuration, It is natural to have control and effect. As described above, the present invention can be applied to all DC-DC converters having an insulating function.

DESCRIPTION OF SYMBOLS 1 and 2 ... Input terminal, 3 and 4 ... Output terminal, 10 ... Switching circuit, 11a-14a ... Switch element, 11b-14b ... Diode, 11c-14c ... Capacitor, 20 ... Transformer, 30 ... Output circuit, 31 ... Diode , 32 ... Diode, 40 ... Control circuit, 41 to 44 ... Output signal, 41a to 44a ... On timing threshold signal, 41b to 44b ... Off timing threshold, 51 ... Voltage detection circuit, 60 ... Insulation circuit, 61 to 64 ... Drive 70, voltage control unit, 71 ... subtraction unit, 72 ... PI control unit, 73 and 74 ... proportional unit, 75 ... integration unit, 76 ... addition unit, 77 ... duty limiting unit, 78 ... pulse signal setting unit, 79 ... Output signal generation unit, 80 ... Dead time setting unit, 81 ... Dead time selection unit, 82 ... Dead time limit unit, 91 ... Triangular wave signal unit, 92 ... Triangle DESCRIPTION OF SYMBOLS 101 ... Differential voltage 102 ... Duty value 103 ... Limiting part output Duty value 104 ... Dead time output signal 105 ... Dead time setting signal 106 ... Pulse generation signal 200 ... DCDC converter 300 ... Vehicle power supply control part 400 ... HV system equipment, 500 ... auxiliary equipment, 600 ... relay, A and B ... connection point, C1 ... capacitor, C2 ... capacitor, L1 ... resonance inductance, L2 ... smooth coil, N1 ... primary winding, N2a ... secondary winding, N2b ... secondary winding, S ... rectification connection point, T ... neutral point, V1 and V2 ... DC power supply, R1 and R2 ... load, VR1 ... voltage value, IR1 ... current value, IR2 …Current value

Claims (14)

A DC-DC converter comprising an input terminal, an output terminal, a plurality of switch elements, and a control circuit for controlling a dead time between the plurality of switch elements, wherein a device different from the DC-DC converter is provided. Used in existing power systems,
The control circuit is a DC-DC converter that changes at least one dead time between the plurality of switch elements based on operation information of a device different from the DC-DC converter. A DC-DC converter according to claim 1, comprising:
The DC-DC converter is a DC-DC converter mounted on a vehicle. A DC-DC converter according to claim 2, comprising:
A plurality of devices different from the DCDC converter are provided,
A DCDC converter that changes the dead time command stepwise based on operation information of the plurality of devices. A DC-DC converter according to claim 2 or 3,
The operation information of the device different from the DC-DC converter is any of a driving state, a stopped state, an input voltage, an output voltage, an input current, and an output current of the device different from the DC-DC converter mounted on the vehicle. A DC-DC converter. The DC-DC converter according to any one of claims 2 to 4,
The device different from the DC-DC converter is a DC-DC converter which is a device connected to the input terminal or the output terminal in parallel or via a battery. A DC-DC converter according to claim 5, comprising:
The DC-DC converter which lengthens the dead time, so that there are few drive numbers of the apparatus different from the said DC-DC converter connected in parallel with the said output terminal. A DC-DC converter according to claim 5, comprising:
The DC-DC converter which lengthens the dead time, so that the voltage applied to the apparatus different from the said DC-DC converter connected in parallel with the said input terminal is large. A DC-DC converter according to claim 5, comprising:
The DC-DC converter which lengthens the dead time, so that the electric current which flows into the apparatus different from the said DC-DC converter connected in parallel with the said output terminal, or the electric current proportional to this is small. A DC-DC converter according to any one of claims 2 to 5,
The operation information of the device different from the DC-DC converter is a DC-DC converter that is information related to the stop of the device depending on the state of charge of the vehicle via the plug. A DC-DC converter according to claim 9, comprising:
A device different from the DC-DC converter is a DC-DC converter that is one of a charger, an inverter that supplies electric power to a motor that generates driving force of the vehicle, and a pump that circulates a coolant. The DC-DC converter according to any one of claims 2 to 10,
When the value of the dead time calculated by the control circuit is larger than the maximum dead time value, the control circuit sets the dead time value of the control circuit as the maximum dead time value,
A DC-DC converter in which when the dead time value calculated by the control circuit is smaller than the minimum dead time value, the dead time value of the control circuit is the minimum dead time value. The DC-DC converter according to any one of claims 1 to 11,
The DC-DC converter
With a transformer,
A full bridge type switching circuit provided between the input terminal and the transformer and including first and second legs;
An output circuit provided between the output terminal and the transformer,
The control circuit is a DC-DC converter that controls a phase shift of the switching circuit and changes a dead time of at least one of the first and second legs. A power supply system comprising any one of the DC-DC converters according to claim 1,
A power supply system having a device different from the DC-DC converter. An automobile comprising the power supply system according to claim 13,
The device different from the DC-DC converter is an automobile that is one of a vehicle drive inverter, an in-vehicle charger, a quick charger, and a pump for circulating a coolant.

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