WO2020070789A1 - Dispositif de conversion de courant - Google Patents

Dispositif de conversion de courant

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Publication number
WO2020070789A1
WO2020070789A1 PCT/JP2018/036807 JP2018036807W WO2020070789A1 WO 2020070789 A1 WO2020070789 A1 WO 2020070789A1 JP 2018036807 W JP2018036807 W JP 2018036807W WO 2020070789 A1 WO2020070789 A1 WO 2020070789A1
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WO
WIPO (PCT)
Prior art keywords
control unit
voltage
transformer
timing
duty ratio
Prior art date
Application number
PCT/JP2018/036807
Other languages
English (en)
Japanese (ja)
Inventor
編絹 中林
竹島　由浩
大斗 水谷
岩蕗　寛康
Original Assignee
三菱電機株式会社
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 三菱電機株式会社 filed Critical 三菱電機株式会社
Priority to PCT/JP2018/036807 priority Critical patent/WO2020070789A1/fr
Priority to JP2020550975A priority patent/JP6937939B2/ja
Publication of WO2020070789A1 publication Critical patent/WO2020070789A1/fr

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    • 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

Definitions

  • the present application relates to a power converter, and more particularly to a power converter having a transformer to which positive and negative voltages are applied.
  • an isolated DC-DC converter which is a power converter including a transformer to which positive and negative voltages are applied
  • the transformer is magnetized, and the power conversion function is impaired.
  • two rectifiers for rectifying the secondary voltages Vs1 and Vs2 output from the secondary terminals of the transformer, and each DC voltage rectified by the two rectifiers are integrated individually and with time.
  • an integrator for outputting the two voltage-time products obtained as follows. By controlling the deviation between the two voltage-time products to be zero, the magnetic bias of the transformer is suppressed (for example, Patent Document 1).
  • the transformer demagnetization is detected by detecting the secondary voltages Vs1 and Vs2 of the transformer and obtaining a product of two voltage times. For this reason, two voltage detecting units and two integrating units are required, and the secondary winding of the transformer is limited to the center tap type. For this reason, there is a problem that it is difficult to reduce the size of the device configuration and the degree of freedom in design is small.
  • the present application discloses a technique for solving the above-described problem, and can reliably suppress the transformer's magnetization, and can reduce the size of the device configuration and improve the design flexibility.
  • An object is to provide a power converter.
  • the power conversion device disclosed in the present application includes a transformer, a first semiconductor switching element that applies a positive voltage to the transformer when turned on, and a second semiconductor switching element that applies a negative voltage to the transformer when turned on.
  • a switching circuit connected between the primary side of the transformer and the DC power supply to convert power between DC / AC, and a rectifier diode, a smoothing reactor, and a smoothing capacitor;
  • a power converter for converting the power from the DC power supply to supply the power to the load, and a controller for controlling the output of the power converter.
  • the control unit generates a duty ratio of the first and second semiconductor switching elements so that a first detection value obtained by detecting an output voltage of the rectifier circuit at a first timing follows a command value.
  • a voltage control unit that controls a second switching element; and a biasing unit that detects biasing of the transformer and individually corrects the duty ratios of the first and second semiconductor switching devices so as to suppress the biasing.
  • a control unit Then, the demagnetization control unit detects at least one of the output voltage of the rectifier circuit and the current of the smoothing reactor at two second timings at a half cycle interval in each cycle of the drive cycle, and The magnetic field is detected based on the difference between the second detection values.
  • the power conversion device disclosed in the present application it is possible to reliably suppress the demagnetization of the transformer, reduce the size of the device configuration, and improve the design flexibility.
  • FIG. 1 is a diagram illustrating a schematic configuration of a power conversion device according to a first embodiment.
  • FIG. 3 is a functional block diagram of a control unit of the power conversion device according to the first embodiment.
  • FIG. 4 is a diagram illustrating generation of a gate drive signal according to the first embodiment.
  • FIG. 3 is an operation waveform diagram for describing an operation in a normal state in the power conversion device according to the first embodiment.
  • 5 is a flowchart for explaining the operation of the magnetization control unit according to the first embodiment.
  • FIG. 5 is an operation waveform diagram for describing an operation when a magnetic bias occurs in the power converter according to the first embodiment.
  • FIG. 5 is an operation waveform diagram for describing an operation when a magnetic bias occurs in the power converter according to the first embodiment.
  • FIG. 5 is an operation waveform diagram for describing an operation when a magnetic bias occurs in the power converter according to the first embodiment.
  • FIG. 5 is a functional block diagram of a control unit according to another example of the first embodiment.
  • FIG. 7 is a diagram illustrating a schematic configuration of a power conversion device according to a second embodiment.
  • FIG. 13 is a diagram illustrating a schematic configuration of a power conversion device according to a third embodiment.
  • FIG. 13 is a functional block diagram of a control unit of the power conversion device according to the third embodiment.
  • FIG. 13 is an operation waveform diagram for describing an operation in a normal state in the power conversion device according to the third embodiment.
  • 13 is a flowchart for explaining the operation of the magnetization control unit according to the third embodiment.
  • FIG. 13 is an operation waveform diagram for describing an operation of the power conversion device according to the third embodiment when a magnetic bias occurs.
  • FIG. 13 is an operation waveform diagram for describing an operation of the power conversion device according to the third embodiment when a magnetic bias occurs.
  • FIG. 15 is an operation waveform diagram for describing an operation at a normal time in the power conversion device according to the fourth embodiment.
  • FIG. 13 is an operation waveform diagram for describing an operation of the power conversion device according to the fourth embodiment when a magnetic bias occurs.
  • FIG. 13 is an operation waveform diagram for describing an operation of the power conversion device according to the fourth embodiment when a magnetic bias occurs.
  • FIG. 1 is a diagram illustrating a schematic configuration of the power conversion device according to the first embodiment.
  • the power conversion device 1 includes a power conversion unit 2 and a control unit 3 that controls the output of the power conversion unit 2 to convert DC power (voltage V1) from a DC power supply 4 into power. To supply DC power (voltage V2) to the load 5.
  • the power converter 2 includes a transformer 6, a switching circuit 7 connected between the primary side of the transformer 6 and the DC power supply 4 and performing power conversion between DC / AC, and a secondary circuit of the transformer 6 and the load 5. And a rectifier circuit 8 connected therebetween.
  • the switching circuit 7 includes an input capacitor 9, a MOSFET Q1 as a first semiconductor switching element that applies a positive voltage to the transformer 6 when turned on, a MOSFET Q4, and a MOSFET Q2 as a second semiconductor switching element that applies a negative voltage to the transformer 6 when turned on.
  • a full bridge circuit is formed by the four MOSFETs Q1 to Q4, but is not limited to this.
  • the MOSFETs Q1, Q2, Q3, and Q4 are simply referred to as Q1, Q2, Q3, and Q4.
  • the positive electrode of the input capacitor 9 is connected to the drain terminals of Q1 and Q3, and the negative electrode of the input capacitor 9 is connected to the source terminals of Q2 and Q4.
  • the source terminal of Q1 is connected to the drain terminal of Q2, and the connection point is connected to the primary terminal 6a of the transformer 6.
  • the source terminal of Q3 is connected to the drain terminal of Q4, and the connection point is connected to the primary terminal 6b of the transformer 6.
  • the rectifier circuit 8 includes two rectifier diodes 10 and 11, a smoothing reactor 12, and a smoothing capacitor 13.
  • the transformer 6 has a center tap type secondary winding and three secondary terminals 6c, 6d, 6e.
  • the secondary terminal 6c of the transformer 6 is connected to the anode terminal of the rectifier diode 10, and the secondary terminal 6e of the transformer 6 is connected to the anode terminal of the rectifier diode 11.
  • Each cathode terminal of the rectifier diodes 10 and 11 is connected to one end of a smoothing reactor 12, and the other end of the smoothing reactor 12 is connected to one end of a smoothing capacitor 13.
  • the other end of the smoothing capacitor 13 is connected to a secondary terminal 6d of the transformer 6.
  • the power conversion device 1 further includes a voltage detection unit 20 that detects the output voltage V2 of the rectifier circuit 8.
  • the voltage detector 20 detects the voltage of the smoothing capacitor 13 as the output voltage V2 of the rectifier circuit 8.
  • the control unit 3 includes a voltage control unit 14 and a demagnetization control unit 15, generates a gate drive signal for Q 1 to Q 4 in the switching circuit 7 based on the output of the voltage detection unit 20, and controls the power conversion unit 2. Output control.
  • FIG. 2 is a functional block diagram of the control unit 3.
  • the control unit 3 includes a voltage control unit 14, a magnetization control unit 15, a correction unit 16, and a gate drive signal generation unit 17.
  • the voltage control unit 14 detects the output voltage V2 of the rectifier circuit 8 at a first timing described below, acquires a first detection value V2A, and inputs the first detection value V2A to the feedback calculation unit 141.
  • the feedback calculation unit 141 generates the duty ratio D such that the first detection value V2A follows the command value V2 * that is a constant voltage.
  • the bias control unit 15 detects the output voltage V2 of the rectifier circuit 8 at two second timings, which will be described later, obtains two second detection values V2B1 and V2B2, and inputs the values to the feedback calculation unit 151.
  • the feedback calculation unit 151 generates the correction amounts ⁇ a and ⁇ b such that the difference between the two second detection values V2B1 and V2B2 approaches zero.
  • the control amount ⁇ is calculated so that the difference between the two second detection values V2B1 and V2B2 approaches 0, and the correction amounts ⁇ a and ⁇ b are ( ⁇ / 2, ⁇ / 2) or ( ⁇ , 0). And so on, so that the difference between the two correction amounts ⁇ a and ⁇ b becomes ⁇ .
  • the output of the voltage control unit 14 and the output of the magnetization control unit 15 are input to the correction unit 16.
  • the correction unit 16 includes two adders 16a and 16b.
  • the duty ratio D is corrected by adding the correction amount ⁇ a by the adder 16a, and the duty ratio D1 of Q1 and Q4 is generated.
  • the duty ratio D is corrected by adding the correction amount ⁇ b by the adder 16b, and the duty ratio D2 of Q2 and Q3 is generated.
  • the gate drive signal generator 17 includes comparators 171 and 172.
  • the comparator 171 receives the duty ratio D1 and the carrier wave Ca1, and outputs a gate drive signal G1 to Q1 and Q4 by PWM (pulse width modulation) control. Further, the duty ratio D2 and the carrier wave Ca2 are input to the comparator 172, and the comparator 172 outputs a gate drive signal G2 to Q2 and Q3 by PWM control.
  • FIG. 3 is a diagram illustrating generation of the gate drive signals G1 and G2.
  • the gate drive signals G1 and G2 are generated by comparing the duty ratios D1 and D2 with the carrier waves Ca1 and Ca2.
  • the two carrier waves Ca1 and Ca2 have the same waveform with the phase shifted by a half cycle T / 2.
  • FIG. 4 is an operation waveform diagram for explaining a normal operation of power conversion device 1.
  • the correction amounts ⁇ a and ⁇ b output by the bias control unit 15 are 0, and the gate drive signals G1 and G2 are generated based on the duty ratio D generated by the voltage control unit 14.
  • FIG. 4 shows the on / off signals of Q1 and Q4, the on / off signals of Q2 and Q3, the primary voltage Vtr of the transformer 6, the current IL of the smoothing reactor 12, the current IC of the smoothing capacitor 13, and the output voltage V2. Show.
  • the on / off signals of Q1 and Q4 and the on / off signals of Q2 and Q3 are signals indicating the timing of actually turning on / off and applying a voltage to the transformer 6, and are not necessarily the gate drive signals G1 and G2 generated by the control unit 3. They do not match.
  • the on / off signals of Q1 and Q4 and the on / off signals of Q2 and Q3 coincide with the gate drive signals G1 and G2 in order to show a normal state in which no magnetic demagnetization of the transformer 6 occurs.
  • the ripple component of V2 fluctuates.
  • the above-described first detection value V2A is detected at a first timing when the output voltage V2 becomes an average value of one cycle, for example, at a phase 0 (t0) and a phase ⁇ (t01), every half cycle or every cycle.
  • the timing at which Q1 and Q4 are turned on is set to phase 0 and the first timings t0 and t01.
  • the two second detection values V2B1 and V2B2 are detected at two second timings t1 and t2 at which the ripple voltage of the output voltage V2 becomes maximum. These two second timings t1 and t2 are half-period intervals in each cycle, and are the center of the entire off-period in which both Q1 and Q4 and Q2 and Q3 are off.
  • the second timings t1 and t2 in each cycle are represented by the following equations (1) and (2).
  • the ON times of Q1 and Q4 and the ON times of Q2 and Q3 are the same ton, and T is a drive cycle.
  • t2 (3T / 2-ton) / 2 (2)
  • the magnetization control unit 15 determines the second timings t1 and t2 based on the gate drive signals G1 and G2 at the duty ratio D, that is, based on the calculation result of the voltage control unit 14. Then, by sampling the output of the voltage detection unit 20 at the second timings t1 and t2, two second detection values V2B1 and V2B2 are obtained.
  • FIG. 5 is a flowchart illustrating the operation of the magnetization control unit 15.
  • the magnetization control unit 15 determines whether or not a difference (V2B1 ⁇ V2B2) between the two second detection values V2B1 and V2B2 detected at the second timings t1 and t2 is zero. (Step S1). If (V2B1 ⁇ V2B2) is 0, it is determined that no magnetic bias has occurred in the transformer 6, and the correction amounts ⁇ a and ⁇ b are both set to 0 (step S2). Thereby, in the control unit 3, the gate drive signals G1 and G2 are generated based on the duty ratio D generated by the voltage control unit 14, and the normal voltage control is continued.
  • step S3 it is determined whether (V2B1-V2B2) is positive (step S3). If (V2B1 ⁇ V2B2) is positive, it is determined that the transformer 6 has a negative magnetic bias, and the correction amounts ⁇ a and ⁇ b satisfying ⁇ a> 0 and ⁇ b ⁇ 0 are determined (step S4).
  • the control unit 3 generates the gate drive signal G1 based on the duty ratio D1 larger than the duty ratio D generated by the voltage control unit 14, and generates the gate drive signal G2 based on the duty ratio D2 smaller than the duty ratio D. Is done. Then, the on-time of Q1 and Q4 is adjusted to be long, and the on-time of Q2 and Q3 is adjusted to be short, so that the negative-side magnetization is suppressed.
  • step S5 If (V2B1 ⁇ V2B2) is not positive in step S3, (V2B1 ⁇ V2B2) is negative and it is determined that the transformer 6 has a positive-side magnetization, and ⁇ a ⁇ 0 and ⁇ b> 0.
  • the correction amounts ⁇ a and ⁇ b are determined (step S5).
  • the control unit 3 generates the gate drive signal G1 based on the duty ratio D1 smaller than the duty ratio D generated by the voltage control unit 14, and generates the gate drive signal G2 based on the duty ratio D2 larger than the duty ratio D. Is done.
  • the on-time of Q1 and Q4 is adjusted to be short, and the on-time of Q2 and Q3 is adjusted to be long, so that the positive-side demagnetization is suppressed.
  • steps S4 and S5 the two correction amounts ⁇ a and ⁇ b are determined to have polarities opposite to each other, but one of them may be set to 0 as described above.
  • FIGS. 6 and 7 are operation waveform diagrams for explaining the operation of the power conversion device 1 at the time of occurrence of magnetic polarization.
  • FIG. 6 The operation of FIG. The case where the correction amount ⁇ a is set to 0 and the control amount ⁇ is applied only to the duty ratio D2 is shown.
  • the switching timing is changed for some reason. It is assumed that positive side magnetization has occurred due to deviation or the like.
  • the on-time of Q2 and Q3 is shortened, and the output voltage V2 detected at the second timing t1 and t2 is such that the value (V2B2) at the second timing t2 after Q2 and Q3 are turned on is Q1 and Q4. Becomes higher than the value (V2B1) at the second timing t1 after turning on.
  • the second timings t1 and t2 are timings determined by ton based on the duty ratio D, and the second detection values (V2B1, V2B2) are detected as in the normal case.
  • the two second timings t1 and t2 are timings at which the ripple voltage of the output voltage V2 becomes the maximum in the normal state, and the ripple voltage of the output voltage V2 does not always become the maximum when the demagnetization occurs.
  • the bias control unit 15 detects the output voltage V2 of the rectifier circuit 8 at two second timings t1 and t2 at half cycle intervals in each cycle of the drive cycle T. Then, the magnetic bias of the transformer 6 is detected based on the difference between the two second detection values V2B1 and V2B2. Then, feedback control is performed so that the difference between the two second detection values V2B1 and V2B2 is reduced, and the duty ratio D1 of Q1 and Q4 and the duty ratio D2 of Q2 and Q3 are individually corrected and generated.
  • the magnetization control unit 15 determines the second timings t1 and t2 based on the calculation result of the voltage control unit 14, it is possible to easily determine the optimal second timings t1 and t2 for the detection of the magnetization.
  • the duty ratio D is corrected using only the correction amounts ⁇ a and ⁇ b calculated by the feedback calculation unit 151.
  • feedforward control may be used together.
  • the feedforward calculation unit 18 calculates the feedforward term ⁇ f such that the difference between the current integrals of the smoothing reactor 12 becomes 0 between the ON periods of Q1 and Q4 and the ON periods of Q2 and Q3.
  • the current values IL-t1, IL-t2, IL-t0, and IL-t01 of the smoothing reactor 12 at the second timings t1 and t2 and the timings t0 and t01 at the phases 0 and ⁇ , and the voltage control unit 14 Is calculated based on the duty ratio D generated by the following equation (3).
  • T is a driving cycle.
  • the demagnetization control unit 15a sets the correction amounts ⁇ a and ⁇ b to ⁇ / 2 and ⁇ / 2, and adds the ⁇ f to ⁇ / 2 by the adder 152 to generate the duty ratio D1. ( ⁇ / 2 + ⁇ f) is generated, and ⁇ f is subtracted from ⁇ / 2 by the subtracter 153 to generate a correction amount ( ⁇ / 2 ⁇ f) for generating the duty ratio D2.
  • the feedforward term ⁇ f is also doubled and only one of addition and subtraction is used.
  • the feedforward term ⁇ f calculated so that the difference between the integrated values of the currents IL between the on-periods of Q1 and Q4 and the on-periods of Q2 and Q3 becomes zero, and the correction amounts ⁇ a and ⁇ b which are feedback terms. Synthesized. As a result, the amount of correction for generating the duty ratios D1 and D2 can be reduced, and the time required for suppressing the magnetic bias can be shortened.
  • the detection of magnetic declination is determined based on whether the difference between the two second detection values V2B1 and V2B2 is 0, but a dead zone may be provided depending on the detection accuracy.
  • step-down converter is used for the power conversion unit 2
  • any circuit system that can perform DC / DC conversion and controls the output voltage may be used.
  • the MOSFET has been described as the semiconductor switching element.
  • an IGBT Insulated Gate Bipolar Transistor
  • a silicon carbide MOSFET silicon carbide MOSFET
  • a gallium nitride high electron mobility transistor HEMT
  • a triangular wave is used for the carrier waves Ca1 and Ca2, but a sawtooth wave or an inverse sawtooth wave may be used, and the same effect is obtained.
  • the two second timings t1 and t2 at half-cycle intervals are represented by the above equations (1) and (2).
  • the present invention is not limited to this.
  • the timing may be two times at half cycle intervals in each cycle.
  • the calculation results of the voltage control unit 14 need not be used for generating the second timings t1 and t2.
  • a plurality of pairs of the second timings t1 and t2 at two half-cycle intervals may be provided in one cycle, and the accuracy of the detection of the demagnetization can be improved.
  • FIG. 9 is a diagram illustrating a schematic configuration of the power conversion device according to the first embodiment.
  • the power conversion device 1a includes a power conversion unit 2a and a control unit 3 that controls the output of the power conversion unit 2a, and converts the DC power (voltage V1) from the DC power supply 4 into power. To supply DC power (voltage V2) to the load 5.
  • the power conversion unit 2 a includes a transformer 6, a switching circuit 7 connected between the primary side of the transformer 6 and the DC power supply 4 and performing power conversion between DC / AC, and a secondary circuit of the transformer 6 and the load 5. And a rectifier circuit 8a connected therebetween.
  • the secondary winding of the transformer 6 is a center tap type having three secondary terminals 6c, 6d, and 6e.
  • the secondary winding of the transformer 6 is There are only two side terminals 6c and 6e at both ends of the secondary winding.
  • the rectifier circuit 8a includes a full bridge circuit including four rectifier diodes 10a, 10b, 11a, and 11b, a smoothing reactor 12, and a smoothing capacitor 13. Other configurations are the same as those in the first embodiment. In this case, when the secondary voltage of the transformer 6 is positive, current flows through the rectifier diodes 10a and 10b, and when the secondary voltage of the transformer 6 is negative, current flows through the rectifier diodes 11a and 11b. In addition, during the period when the secondary voltage of the transformer 6 is zero, that is, when there is no power transmission, a return current flows with all the rectifier diodes 10a, 10b, 11a, and 11b in a forward bias state.
  • the configuration and operation of the control unit 3 are the same as those in the first embodiment, and the same effects can be obtained. That is, the bias control section 15 detects the output voltage V2 of the rectifier circuit 8a at two second timings t1 and t2 at half cycle intervals in each cycle of the driving cycle T, and the two second detections are performed. The magnetic bias of the transformer 6 is detected based on the difference between the values V2B1 and V2B2. Then, feedback control is performed so that the difference between the two second detection values V2B1 and V2B2 is reduced, and the duty ratio D1 of Q1 and Q4 and the duty ratio D2 of Q2 and Q3 are individually corrected and generated.
  • the two second detection values V2B1 and V2B2 can be acquired by using the voltage detection unit 20 used for the voltage control at the time of normal operation, and the magnetic bias of the transformer 6 can be detected, as described in the related art. It does not require a voltage detection unit and an integration unit for detecting magnetic bias. For this reason, it is possible to reduce the size of the device configuration and reliably suppress the magnetic bias of the transformer 6.
  • the feedforward control may be used together with the feedback control. That is, the feedforward term ⁇ f is calculated and used so that the difference between the current integrated values of the smoothing reactor 12 becomes 0 between the ON periods of Q1 and Q4 and the ON periods of Q2 and Q3. As a result, the time required for suppressing the magnetization can be shortened.
  • FIG. 10 is a diagram illustrating a schematic configuration of a power conversion device according to the third embodiment.
  • the power conversion device 1 b includes a power conversion unit 2 similar to that of the first embodiment and a control unit 3 a that controls the output of the power conversion unit 2.
  • the voltage V ⁇ b> 1) is converted into electric power, and DC power (voltage V ⁇ b> 2) is supplied to the load 5.
  • Power conversion device 1b includes a voltage detection unit 20 for detecting the voltage (output voltage V2) of smoothing capacitor 13, and a current detection unit for detecting current IL of smoothing reactor 12, as in the first embodiment. 21.
  • the control unit 3a includes a voltage control unit 14 and a magnetization control unit 15b. Based on the output of the voltage detection unit 20, the control unit 3a generates a gate drive signal to Q1 to Q4 in the switching circuit 7 and controls the power conversion unit 2 to operate. Output control.
  • FIG. 11 is a functional block diagram of the control unit 3a. As shown in FIG. 11, the control unit 3a includes a voltage control unit 14, a magnetization control unit 15b, a correction unit 16, and a gate drive signal generation unit 17. The configuration other than the magnetization control unit 15b is the same as that of the above-described first embodiment, and thus the description will be appropriately omitted.
  • the demagnetization control unit 15b detects the current IL of the smoothing reactor 12 at two second timings t1a and t2a, acquires two second detection values IL1 and IL2, and inputs them to the feedback calculation unit 154.
  • the feedback calculation unit 154 generates the correction amounts ⁇ aa and ⁇ bb such that the difference between the two second detection values IL1 and IL2 approaches zero.
  • the determination of the correction amounts ⁇ aa and ⁇ bb is the same as in the first embodiment.
  • the control amount ⁇ is calculated so that the difference between the two second detection values IL1 and IL2 approaches 0, and the correction amounts ⁇ aa and ⁇ aa are calculated.
  • ⁇ bb is generated such that the difference between the two correction amounts ⁇ aa and ⁇ bb, such as ( ⁇ / 2, ⁇ / 2) or ( ⁇ , 0), becomes ⁇ .
  • the output of the voltage control unit 14 and the output of the demagnetization control unit 15b are input to the correction unit 16, and the Duty ratio D is individually corrected by the two correction amounts ⁇ aa and ⁇ bb to obtain the duty ratio D1 of Q1 and Q4.
  • the duty ratio D2 of Q2 and Q3 is generated.
  • FIG. 12 is an operation waveform diagram for describing a normal operation of power conversion device 1b.
  • the correction amounts ⁇ aa and ⁇ bb output from the magnetization control unit 15b are 0, and the gate drive signals G1 and G2 are generated based on the duty ratio D generated by the voltage control unit 14.
  • the operation waveform is the same as the operation waveform shown in FIG.
  • the first detection value V2A is detected at a first timing when the output voltage V2 becomes an average value of one cycle, for example, at a phase 0 (t0) and a phase ⁇ (t01) every half cycle or every cycle.
  • the timing at which Q1 and Q4 are turned on is set to phase 0 and the first timings t0 and t01.
  • the two second detection values IL1 and IL2 are detected at two second timings t1a and t2a at which the ripple current of the current IL of the smoothing reactor 12 is maximized.
  • These two second timings t1a and t2a are half-cycle intervals in each cycle, and are the timing when Q1 and Q4 turn off and the timing when Q2 and Q3 turn off.
  • the second timings t1a and t2a in each cycle are represented by the following equations (4) and (5).
  • the ON times of Q1 and Q4 and the ON times of Q2 and Q3 are the same ton, and T is a drive cycle.
  • the magnetization control unit 15b determines the second timings t1a and t2a based on the gate drive signals G1 and G2 at the duty ratio D, that is, based on the calculation result of the voltage control unit 14. Then, by sampling the output of the current detection unit 21 at the second timings t1a and t2a, two second detection values IL1 and IL2 are obtained.
  • FIG. 13 is a flowchart illustrating the operation of the magnetization control unit 15b.
  • the magnetization control unit 15b determines whether the difference (IL1 ⁇ IL2) between the two second detection values IL1 and IL2 detected at the second timings t1a and t2a is 0. (Step SS1). If (IL1 ⁇ IL2) is 0, it is determined that no magnetic bias has occurred in the transformer 6, and the correction amounts ⁇ a and ⁇ b are both set to 0 (step SS2). Thereby, in the control unit 3a, the gate drive signals G1 and G2 are generated based on the duty ratio D generated by the voltage control unit 14, and the normal voltage control is continued.
  • step SS3 If it is determined in step SS1 that (IL1 ⁇ IL2) is not 0, it is determined that the transformer 6 is demagnetized.
  • correction amounts ⁇ aa and ⁇ bb satisfying ⁇ aa ⁇ 0 and ⁇ bb> 0 are determined (step SS3).
  • the gate drive signal G1 is generated based on the duty ratio D1 smaller than the duty ratio D generated by the voltage control unit 14, and the gate drive signal G2 is generated based on the duty ratio D2 larger than the duty ratio D. Is done.
  • the ON times of Q1 and Q4 are adjusted to be short, and the ON times of Q2 and Q3 are adjusted to be long.
  • step SS4 it is determined whether or not the absolute value of (IL1 ⁇ IL2) has decreased. That is, it is determined whether or not the difference (IL1 ⁇ IL2) between the two second detection values IL1 and IL2 approaches 0 to suppress the magnetization (step SS4).
  • the absolute value of (IL1 ⁇ IL2) decreases, the assumption (the occurrence of positive-side demagnetization) is determined to be valid, and the control for suppressing the positive-side demagnetization, ie, ⁇ aa ⁇ 0, ⁇ bb> 0, is established.
  • the control of the magnetic depolarization suppression using the correction amounts ⁇ aa and ⁇ bb is continued (step SS5).
  • step SS4 when the absolute value of (IL1 ⁇ IL2) increases without decreasing, it is determined that the transformer 6 has a negative-side bias, and the correction amounts ⁇ aa, ⁇ aa> 0 and ⁇ bb ⁇ 0, ⁇ bb is determined (step SS6).
  • the gate drive signal G1 is generated based on the duty ratio D1 larger than the duty ratio D generated by the voltage control unit 14, and the gate drive signal G2 is generated based on the duty ratio D2 smaller than the duty ratio D. Is done.
  • the on-time of Q1 and Q4 is adjusted to be long, and the on-time of Q2 and Q3 is adjusted to be short, so that the negative-side magnetization is suppressed.
  • the two correction amounts ⁇ aa and ⁇ bb are determined to have polarities opposite to each other, one of them may be set to 0 as described above.
  • FIGS. 14 and 15 are operation waveform diagrams for explaining the operation of the power conversion device 1b at the time of occurrence of magnetic polarization.
  • FIG. The operation of FIG. 14 shows a case where the correction amount ⁇ aa is set to 0 and the control amount ⁇ is applied only to the duty ratio D2
  • FIG. 15 shows a case where the correction amount ⁇ bb is set to 0 and the control amount ⁇ is applied only to the duty ratio D1.
  • the gate drive signals G1 and G2 are generated based on the duty ratio D generated by the voltage control unit 14, and when the voltage control in the normal state is performed, the switching timing is changed for some reason. It is assumed that a negative side magnetization occurs due to a deviation or the like. In this case, the on-time of Q2 and Q3 is prolonged, and negative-side magnetic bias occurs. When the magnetic bias occurs, the current IL of the smoothing reactor 12 increases, and the current IL detected at the second timings t1a and t2a has a value (IL2) at the second timing t2a, which is late, at the second timing t1a. (IL1).
  • the difference (IL1 ⁇ IL2) between the two second detection values becomes a value other than 0, and the magnetization is detected.
  • the correction amounts ⁇ aa and ⁇ bb in the direction in which the magnetization is suppressed are generated, and the duty ratio D1 of Q1 and Q4 and the duty ratio D2 of Q2 and Q3 are generated individually.
  • the demagnetization suppression control is started. In this case, since the control amount ⁇ is applied only to the duty ratio D2, the on-time of Q1 and Q4 does not change, and the on-time of Q2 and Q3 is adjusted to be shorter, and the negative-side demagnetization is suppressed. Is done.
  • the correction amounts ⁇ aa and ⁇ bb in the direction in which the magnetization is suppressed are generated, and the duty ratio D1 of Q1 and Q4 and the duty ratio D2 of Q2 and Q3 are generated individually.
  • the demagnetization suppression control is started.
  • the control amount ⁇ is applied only to the duty ratio D1
  • the on-time of Q2 and Q3 does not change, and the on-time of Q1 and Q4 is adjusted so as to be shortened, thereby suppressing the positive-side demagnetization. Is done.
  • the second timings t1a and t2a are timings determined by ton based on the duty ratio D, and the second detection values (IL1 and IL2) are detected as in the normal case.
  • the two second timings t1a and t2a are timings at which the ripple current of the current IL of the smoothing reactor 12 is maximized in a normal state, and the ripple current of the current IL is not always maximized when a magnetic demagnetization occurs.
  • the demagnetization control unit 15b detects the current IL of the smoothing reactor 12 at two second timings t1a and t2a at half-cycle intervals in each drive cycle T. , Based on the difference between the two second detection values IL1 and IL2. Then, feedback control is performed so that the difference between the two second detection values IL1 and IL2 is reduced, and the duty ratio D1 of Q1 and Q4 and the duty ratio D2 of Q2 and Q3 are individually corrected and generated.
  • the current detection unit 21 for detecting the current IL of the smoothing reactor 12 can be used to acquire the two second detection values IL1 and IL2 to detect the magnetic bias of the transformer 6. For this reason, it is not necessary to detect positive and negative voltages or currents for the detection of the magnetic polarization, and a detection unit and an integration unit for detecting the magnetic polarization are not required as shown in the related art. Therefore, as in the first embodiment, the size of the device can be reduced, and the bias of the transformer 6 can be suppressed with high reliability. Further, since it is not necessary to individually detect positive and negative voltages or currents on the secondary side of the transformer 6, the secondary winding of the transformer need not be limited to the center tap type, and the degree of freedom in design is improved.
  • the magnetization control unit 15b determines the second timings t1a and t2a based on the calculation result of the voltage control unit 14, it is possible to easily determine the optimal second timings t1a and t2a for detecting the magnetization.
  • the two second timings t1a and t2a at half-cycle intervals are timings at which the ripple current of the current IL of the smoothing reactor 12 is maximized, but the present invention is not limited to this.
  • the timing at which the ripple current of the current IL becomes minimum is defined as the second timings t1b and t2b.
  • Other configurations are the same as those of the third embodiment, that is, the configuration of the power converter 1b shown in FIG. 10 and the configuration of the control unit 3a shown in FIG. 11 are the same as those of the third embodiment.
  • FIG. 16 is an operation waveform diagram for describing a normal operation of power conversion device 1b according to the present embodiment.
  • the correction amounts ⁇ aa and ⁇ bb output from the magnetization control unit 15b are 0, and the gate drive signals G1 and G2 are generated based on the duty ratio D generated by the voltage control unit 14.
  • the operation waveform is the same as the operation waveform shown in FIG.
  • the first detection value V2A is detected at a first timing t0, t01 at which the output voltage V2 becomes an average value of one cycle, and every half cycle or one cycle.
  • the two second detection values IL1 and IL2 are detected at two second timings t1b and t2b at which the ripple current of the current IL of the smoothing reactor 12 is minimized.
  • the two second timings t1b and t2b are half-cycle intervals in each cycle, and are the timing when Q1 and Q4 turn on and the timing when Q2 and Q3 turn on.
  • the second timings t1b and t2b in each cycle are the same as the first timings t0 and t01, and are represented by the following equations (6) and (7). Note that T is a driving cycle.
  • the second timings t1b and t2b can be easily determined without using the calculation result of the voltage control unit 14. Then, by sampling the output of the current detection unit 21 at the second timings t1b and t2b, two second detection values IL1 and IL2 are obtained. If the timings when Q1 and Q4 are turned on and the timings when Q2 and Q3 are turned on are not set to the phase 0 (t0) and the phase ⁇ (t01), the second timings t1b and t2b are set to the voltage control unit. The determination is made using the calculation results of No. 14.
  • the magnetization control unit 15b detects and suppresses the magnetization as in the third embodiment. That is, when the difference (IL1 ⁇ IL2) between the two second detection values is other than 0, the magnetism is detected and the correction amounts ⁇ aa and ⁇ bb in the direction in which the magnetization is suppressed are generated, and the voltage control unit is controlled. 14 corrects the duty ratio D generated.
  • FIGS. 17 and 18 are operation waveform diagrams for explaining the operation of the power conversion device 1b at the time of occurrence of magnetic polarization.
  • FIG. The operation of FIG. FIG. 17 shows a case where the correction amount ⁇ aa is 0 and the control amount ⁇ is applied only to the duty ratio D2
  • FIG. 18 shows a case where the correction amount ⁇ bb is 0 and the control amount ⁇ is applied only to the duty ratio D1.
  • the switching timing may be changed for some reason. It is assumed that a negative side magnetization occurs due to a deviation or the like. In this case, the on-time of Q2 and Q3 is prolonged, and negative-side magnetic bias occurs.
  • the current IL of the smoothing reactor 12 increases, and the current IL detected at the second timings t1b and t2b has a value (IL2) at the second timing t2b, which is late, at the second timing t1b. (IL1).
  • the difference (IL1 ⁇ IL2) between the two second detection values becomes a value other than 0, and the magnetization is detected.
  • the correction amounts ⁇ aa and ⁇ bb in the direction in which the magnetization is suppressed are generated, and the duty ratio D1 of Q1 and Q4 and the duty ratio D2 of Q2 and Q3 are generated individually.
  • the demagnetization suppression control is started. In this case, since the control amount ⁇ is applied only to the duty ratio D2, the on-time of Q1 and Q4 does not change, and the on-time of Q2 and Q3 is adjusted to be shorter, and the negative-side demagnetization is suppressed. Is done.
  • the positive-side magnetization has occurred during the normal voltage control.
  • the on-time of Q1 and Q4 becomes long, and the positive side magnetization occurs, and current IL of smoothing reactor 12 increases.
  • the value (IL2) at the second timing t2b which is late, becomes higher than the value (IL1) at the second timing t1b.
  • the difference (IL1 ⁇ IL2) between the two second detection values becomes a value other than 0, and the magnetization is detected. Then, as shown in FIG.
  • the correction amounts ⁇ aa and ⁇ bb in the direction in which the magnetization is suppressed are generated, and the duty ratio D1 of Q1 and Q4 and the duty ratio D2 of Q2 and Q3 are generated individually.
  • the demagnetization suppression control is started. In this case, since the control amount ⁇ is applied only to the duty ratio D1, the on-time of Q2 and Q3 does not change, and the on-time of Q1 and Q4 is adjusted to be shorter, and the positive-side demagnetization is suppressed. Is done.
  • the second timings t1b and t2b are the same as those in the normal state, and the second detection values (IL1 and IL2) are detected as in the normal state.
  • the two second timings t1b and t2b are timings at which the ripple current of the current IL of the smoothing reactor 12 is minimized in a normal state, and the ripple current of the current IL is not necessarily minimized when a magnetic bias occurs.
  • two second detection values IL1 and IL2 are obtained using the current detection unit 21 that detects the current IL of the smoothing reactor 12. It is possible to detect the magnetic bias of the transformer 6. Therefore, the same effect as in the third embodiment can be obtained, the size of the device can be reduced, the bias of the transformer 6 can be suppressed with high reliability, and the degree of freedom in design can be improved.
  • the two second timings t1b and t2b at half-period intervals are timings at which the ripple current of the current IL of the smoothing reactor 12 is maximum or minimum, but is not limited to this. is not.
  • the second timings t1b and t2b are only required to be able to detect a change in the ripple current of the current IL at two times at half cycle intervals in each cycle. In that case, the calculation results of the voltage control unit 14 need not be used for generating the second timings t1b and t2b.
  • a plurality of pairs of two second timings t1b and t2b at half-cycle intervals may be provided in one cycle, and the accuracy of the detection of magnetic declination can be improved.
  • the power converter 1b according to the third and fourth embodiments is applied to a vehicle-mounted power converter that transfers power from a high-voltage battery to a low-voltage load, it is possible to effectively promote downsizing, and to improve reliability. Since the magnetism can be suppressed, a great effect can be obtained.
  • the detection of magnetic declination is determined based on whether the difference between the two second detection values IL1 and IL2 is 0, but a dead zone may be provided.

Abstract

La présente invention concerne une unité de conversion de courant (2) comprenant : un transformateur (6) ; un circuit de commutation (7) qui comprend des éléments de commutation (Q1, Q4) destinés à appliquer une tension positive et des éléments de commutation (Q2, Q3) destinés à appliquer une tension négative, et qui est connecté au côté primaire du transformateur (6) ; et un circuit de redressement (8) qui est connecté au côté secondaire du transformateur (6). Une unité de commande (3) génère un rapport cyclique et commande une première valeur de détection (V2A) obtenue par détection d'une tension de sortie, et effectue en outre une détection à deux seconds moments à un intervalle de demi-période dans chaque période de commande, détecte une asymétrie magnétique sur la base de la différence entre les deux secondes valeurs de détection (V2B1, V2B2), et corrige séparément les rapports cycliques des éléments de commutation (Q1, Q4) et des éléments de commutation (Q2, Q3) de façon à supprimer l'asymétrie magnétique.
PCT/JP2018/036807 2018-10-02 2018-10-02 Dispositif de conversion de courant WO2020070789A1 (fr)

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PCT/JP2018/036807 WO2020070789A1 (fr) 2018-10-02 2018-10-02 Dispositif de conversion de courant
JP2020550975A JP6937939B2 (ja) 2018-10-02 2018-10-02 電力変換装置

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006333569A (ja) * 2005-05-24 2006-12-07 Fuji Electric Systems Co Ltd 直流−直流変換装置の偏磁検出器
WO2009050943A1 (fr) * 2007-10-19 2009-04-23 Murata Manufacturing Co., Ltd. Alimentation électrique à découpage

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006333569A (ja) * 2005-05-24 2006-12-07 Fuji Electric Systems Co Ltd 直流−直流変換装置の偏磁検出器
WO2009050943A1 (fr) * 2007-10-19 2009-04-23 Murata Manufacturing Co., Ltd. Alimentation électrique à découpage

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