JP2015077046A - Control method for power converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control method for a power converter, capable of suppressing a surge voltage in a power converter having a different control method from a conventional method.SOLUTION: A control circuit 13 shifts from a first control state, in which a switch element 102 is set ON and a switch element 103 is set OFF and also switch elements 120 and 123 are set ON and switch elements 121 and 122 are set OFF, to a second control state, in which the switch elements 102 and 103 are set ON and the switch elements 120-123 are set OFF. However, during the period of the second control state, the control circuit 13 switches the switch elements 120 and 123 to be ON. As a result, current flowing through the switch element 102 comes to zero. Therefore, by switching the switch element 102 to be OFF at timing when the current flowing through the switch element 102 becomes zero, it is possible to suppress a surge voltage which may occur at that time.

Description

  The present invention relates to a method for controlling a power converter.

  Conventionally, as a method for controlling a power converter, for example, there is a method for controlling a DC / DC converter disclosed in Patent Document 1 shown below.

  The DC / DC converter includes a first voltage system circuit, a second voltage system circuit, and a switching control circuit. The first voltage system circuit includes a first switch element and a second switch element. The second voltage system circuit includes a third switch element and a fourth switch element. The switching control circuit alternately turns on and off the first switch element and the second switch element, and turns on and off the third switch element and the fourth switch element in synchronization with the first switch element and the second switch element. . Then, from the first state where the first switch element and the third switch element are turned on, and the second switch element and the fourth switch element are turned off, the first switch element and the third switch element are turned off, When shifting to the second state where the two switch elements and the fourth switch element are turned on, the second switch element is turned on. As a result, the current flowing through the first switch element is quickly reduced. Therefore, by turning off the first switch element at the timing when the current decreases, the surge voltage generated at that time can be suppressed.

Japanese Patent No. 4555881

  However, the above-described DC / DC converter control method alternately turns on and off the first switch element and the second switch element, and synchronizes with the first switch element and the second switch element. This is based on the premise that the four switch elements are turned on and off. Therefore, it cannot be applied when the switching method of the switch elements is different.

  This invention is made in view of such a situation, and it aims at providing the control method of the power converter device which can suppress a surge voltage in the power converter device from which the control method differs from the former. To do.

  The present invention, which has been made to solve the above-mentioned problems, is connected to a transformer having at least one primary winding, one secondary winding, and a primary winding, and is turned on by turning on the primary winding. At least one first switch element that supplies a current to generate a magnetic flux in one direction and is connected to the primary winding and is turned on to supply a current to the primary winding to generate a reverse magnetic flux. A first power conversion circuit having at least one second switch element and a secondary winding connected to the secondary winding and turning on when the primary winding generates a magnetic flux in one direction, At least one third switching element for rectifying the output and the secondary winding connected to the secondary winding and rectified on the output of the secondary winding by turning on when the primary winding generates a magnetic flux in the reverse direction A second power conversion circuit having at least one fourth switch element; The first switch element and the second switch are switched from the first control state in which the switch element is turned on, the second switch element is turned off, the third switch element is turned on, and the fourth switch element is turned off. A second control state in which the element is turned on; a first switch element is turned off; a second switch element is turned on; a third switch element is turned off; and a fourth switch element is turned on After passing through the three control states, a transition is made to a fourth control state in which the first switch element and the second switch element are turned on. Thereafter, the fourth control state is repeated from the first control state, and the first switch element to the fourth switch And a control circuit for controlling the element, wherein the control circuit turns on the third switch element during the second control state. Characterized by a fourth on-state switching element during the fourth control state.

  According to this configuration, the control method is different from the conventional one, and the first to fourth control states are repeated. Then, during the period of the second control state, the control circuit turns on the third switch element, so that a current in the direction opposite to the current flowing through the first switch element can be generated. Therefore, the current flowing through the first switch element can be reduced. Therefore, even when the first switch element is turned off when shifting from the second control state to the third control state, the surge voltage generated at that time can be suppressed. In addition, during the period of the fourth control state, the control circuit turns on the fourth switch element, so that a current in the direction opposite to the current flowing through the second switch element can be generated. Therefore, the current flowing through the second switch element can be suppressed. Therefore, even when the second switch element is turned off when shifting from the fourth control state to the first control state, the surge voltage generated at that time can be suppressed. Thereby, it is possible to suppress the surge voltage in the power conversion device that is controlled differently from the conventional one.

It is a circuit diagram of the power converter in a 1st embodiment. It is a circuit diagram for demonstrating the capacitor | condenser and parasitic diode which consist of the parasitic capacitance of the switch element shown in FIG. It is a timing chart for demonstrating the control method of the power converter device shown in FIG. It is a circuit diagram for demonstrating the control method of the power converter device at the time t10-t11 of the timing chart shown in FIG. FIG. 4 is a circuit diagram for illustrating a method for controlling the power conversion device at times t11 to t12 in the timing chart shown in FIG. 3. FIG. 4 is a circuit diagram for illustrating a method for controlling the power conversion device at times t12 to t13 in the timing chart shown in FIG. 3. It is another circuit diagram for demonstrating the control method of the power converter device at the time t12-t13 of the timing chart shown in FIG. FIG. 4 is a circuit diagram for illustrating a method for controlling the power conversion device at times t13 to t14 in the timing chart shown in FIG. 3. It is a circuit diagram of the power converter device in 2nd Embodiment. It is a circuit diagram for demonstrating the capacitor | condenser and parasitic diode which consist of the parasitic capacitance of the switch element shown in FIG. It is a timing chart for demonstrating the control method of the power converter device shown in FIG. It is a circuit diagram for demonstrating the control method of the power converter device at the time t20-t21 of the timing chart shown in FIG. It is a circuit diagram for demonstrating the control method of the power converter device at the time t21-t22 of the timing chart shown in FIG. It is a circuit diagram for demonstrating the control method of the power converter device at the time t22-t23 of the timing chart shown in FIG. It is a circuit diagram of the power converter device in 3rd Embodiment. FIG. 16 is a circuit diagram for explaining a capacitor and a parasitic diode including a parasitic capacitance of the switch element shown in FIG. 15. It is a timing chart for demonstrating the control method of the power converter device shown in FIG. It is a circuit diagram for demonstrating the control method of the power converter device at the time t30-t31 of the timing chart shown in FIG. It is a circuit diagram for demonstrating the control method of the power converter device in the time t31-t32 of the timing chart shown in FIG. It is a circuit diagram for demonstrating the control method of the power converter device at the time t32-t33 of the timing chart shown in FIG.

  Next, the present invention will be described in more detail with reference to embodiments. In the present embodiment, an example is shown in which the power conversion device according to the present invention is applied to a power conversion device that converts a direct current supplied from a low-voltage battery to charge the high-voltage battery.

(First embodiment)
First, the configuration of the power conversion device according to the first embodiment will be described with reference to FIGS. 1 and 2.

  A power conversion device 1 shown in FIG. 1 is a device that converts a direct current supplied from a low-voltage battery B10 into a high-voltage direct current, supplies the high-voltage battery B11, and charges the high-voltage battery B11. The power conversion device 1 includes a first power conversion circuit 10, a transformer 11, a second power conversion circuit 12, and a control circuit 13.

  The first power conversion circuit 10 is a circuit that converts direct current supplied from the low-voltage battery B10 into alternating current and supplies the alternating current to the transformer 11. The first power conversion circuit 10 includes a capacitor 100, a choke coil 101, and switch elements 102 and 103.

  One end of the capacitor 100 is connected to the positive terminal of the low voltage battery B10, and the other end is connected to the negative terminal of the low voltage battery B10. One end of the choke coil 101 is connected to one end of the capacitor 100, and the other end is connected to the transformer 11.

  The switch elements 102 and 103 are elements that convert the direct current supplied from the low-voltage battery B10 to alternating current by being controlled and switched by the control circuit 13. For example, it is an FET, and as shown in FIG. 2, a capacitor C made of a parasitic capacitance and a parasitic diode D are connected in parallel.

  When the switch element 102 (first switch element) shown in FIG. 1 is turned on, a current is supplied to a primary winding 110 of a transformer 11 described later to generate a magnetic flux in one direction. When the switch element 103 (second switch element) is turned on, a current is supplied to a primary winding 111 of the transformer 11 described later to generate a magnetic flux in the reverse direction. One end of each of the switch elements 102 and 103 is connected to the other end of the capacitor 100, and the other end is connected to the transformer 11. The control terminals of the switch elements 102 and 103 are connected to the control circuit 13 respectively.

  The transformer 11 is an element that converts the alternating current supplied from the first power conversion circuit 10 into an alternating current having a predetermined voltage corresponding to the turns ratio in an insulated state and supplies the alternating current to the second power conversion circuit 12. The transformer 11 has primary windings 110 and 111 and a secondary winding 112. The primary windings 110 and 111 are connected in series. One end of the primary winding 110 is connected to the other end of the switch element 102, and one end of the primary winding 111 is connected to the other end of the switch element 103. A series connection point of the primary windings 110 and 111 is connected to the other end of the choke coil 101. The secondary winding 112 is connected to the second power conversion circuit 12.

  The second power conversion circuit 12 is a circuit that rectifies and converts the alternating current supplied from the secondary winding 112 of the transformer 11 to direct current, and supplies the direct current to the high voltage battery B11. The second power conversion circuit 12 includes switch elements 120 to 123 and a capacitor 124.

  The switch elements 120 to 123 are elements that are controlled by the control circuit 13 and switch to rectify the alternating current supplied from the secondary winding 112 and convert it to direct current. For example, it is an FET, and as shown in FIG. 2, a capacitor C made of a parasitic capacitance and a parasitic diode D are connected in parallel.

  The switch elements 120 and 123 (third switch element) shown in FIG. 1 rectify the output of the secondary winding 112 by turning on when the primary winding 110 generates a magnetic flux in one direction. The switch elements 121 and 122 (fourth switch element) are turned on when the primary winding 111 generates a magnetic flux in the reverse direction, thereby rectifying the output of the secondary winding 112. The switch elements 120 and 121 and the switch elements 122 and 123 are respectively connected in series. The switch elements 120 and 121 connected in series and the switch elements 122 and 123 connected in series are connected in parallel. That is, the switch elements 120 and 121 connected in series and the switch elements 122 and 123 connected in series are arranged such that the switch elements 120 and 123 are diagonally arranged and the switch elements 121 and 122 are arranged diagonally. So that they are connected in parallel. A series connection point of the switch elements 120 and 121 is connected to one end of the secondary winding 112, and a series connection point of the switch elements 122 and 123 is connected to the other end of the secondary winding 112. One end of each of the switch elements 120 and 122 is connected to one end of the capacitor 124 and is connected to the positive end of the high voltage battery B11. One end of each of the switch elements 121 and 123 is connected to the other end of the capacitor 124 and is connected to the negative end of the high voltage battery B11. Control ends of the switch elements 120 to 123 are connected to the control circuit 13, respectively.

  The control circuit 13 is a circuit that controls the switch elements 102, 103, 120 to 123. The control circuit 13 switches from the first control state in which the switch element 102 is turned on, the switch element 103 is turned off, the switch elements 120 and 123 are turned on, and the switch elements 121 and 122 are turned off. While the elements 102 and 103 are turned on, the second control state is entered in which the switch elements 120 to 123 are turned off. Thereafter, the switch element 102 is turned off, the switch element 103 is turned on, the switch elements 120 and 123 are turned off, and the switch elements 121 and 122 are turned on. , 103 are turned on, and the process proceeds to the fourth control state in which the switch elements 120 to 123 are turned off. Thereafter, the first to fourth control states are repeated every cycle Ts. However, the switch elements 120 and 123 are turned on during the second control state, and the switch elements 121 and 122 are turned on during the fourth control state. At this time, based on at least one of the input / output voltage and the input / output current of the first power conversion circuit 10 and the second power conversion circuit 12, the on-time of the switch elements 120 and 123 during the second control state, and The on-time of the switch elements 121 and 122 during the fourth control state is adjusted. The control circuit 13 is connected to the control ends of the switch elements 102, 103, and 120 to 123, respectively.

  Next, a method for controlling the power conversion apparatus according to the first embodiment will be described with reference to FIGS.

  As shown in FIG. 3, the control circuit 13 turns on the switch element 102 and turns off the switch element 103 and turns on the switch elements 120 and 123 during the time t10 to t11 that is the first control state. The switch elements 121 and 122 are turned off. As a result, as shown in FIG. 4, a current flows through a path from the positive terminal of the low voltage battery B10 to the negative terminal of the low voltage battery B10 via the choke coil 101, the primary winding 110, and the switch element 102. At this time, the magnetic energy accumulated in the choke coil 101 is released. As a result, a voltage is induced in the secondary winding 112. As a result, a current flows through a path from one end of the secondary winding 112 to the other end of the secondary winding 112 via the switch element 120, the high voltage battery B11, and the switch element 123. Electric power is supplied to the high voltage battery B11, and the high voltage battery B11 is charged. At this time, electric charge is accumulated in the capacitor 124, and the voltage of the capacitor 124 becomes the same as the voltage of the high voltage battery B11.

  As shown in FIG. 3, the control circuit 13 turns on the switch elements 102 and 103 and turns off the switch elements 120 to 123 during the time t11 to t14 in the second control state. However, the control circuit 13 turns on the switch elements 120 and 123 during the time t12 to t13 during the second control state.

  As shown in FIG. 5, when the switch element 102 is turned on between time t11 and t12, the low voltage battery passes through the choke coil 101, the primary winding 110, and the switch element 102 from the positive terminal of the low voltage battery B10. A current flows through the path leading to the negative electrode end of B10. Further, when the switch element 103 is turned on, a current flows through a path from the positive terminal of the low voltage battery B10 to the negative terminal of the low voltage battery B10 via the choke coil 101, the primary winding 111, and the switch element 103. At this time, magnetic energy is accumulated in the choke coil 101. Since the switch elements 102 and 103 are on, one end of the primary winding 110 and one end of the primary winding 111 are connected. Accordingly, the voltage applied to the primary windings 110 and 111 becomes zero. As a result, no voltage is induced in the secondary winding 112.

  As shown in FIG. 6, when the switch elements 120 and 123 are turned on between time t12 and t13, one end and the other end of the capacitor 124 are connected via the switch element 120, the secondary winding 112, and the switch element 123. . The voltage of the capacitor 124 is the same as the voltage of the high voltage battery B11. As a result, a current flows through a path from one end of the capacitor 124 to the other end of the capacitor 124 via the switch element 120, the secondary winding 112, and the switch element 123. Thereby, a current flows through a path from one end of the primary winding 111 to one end of the primary winding 110 via the switch element 103 and the switch element 102. As a result, the current flowing through the path from the positive electrode end of the low voltage battery B10 to the negative electrode end of the low voltage battery B10 via the choke coil 101, the primary winding 110, and the switch element 102 is quickly reduced to 0. Then, as shown in FIGS. 3 and 7, the direction of the current is reversed and flows in the opposite direction. On the other hand, the current flowing through the path from the positive end of the low voltage battery B10 to the negative end of the low voltage battery B10 via the choke coil 101, the primary winding 111, and the switch element 103 increases rapidly.

  As shown in FIG. 2, a capacitor C made of a parasitic capacitance is connected to the switch elements 120 and 123 in parallel. When the switch elements 120 and 123 are turned off between times t13 and t14, resonance occurs at a frequency determined by the leakage inductance of the transformer 11, the parasitic capacitances of the switch elements 120 and 123, and the like. As a result, as shown in FIGS. 3 and 8, the current flowing through the switch element 102 becomes zero.

  As shown in FIG. 3, the control circuit 13 turns off the switch element 102 and turns on the switch elements 121 and 122 at time t14 when the current flowing through the switch element 102 becomes zero. Since the switch element 102 is turned off at the timing when the current flowing through the switch element 102 becomes zero, the surge voltage generated at that time becomes very small. As a result, the switch element 102 is turned off, the switch element 103 is turned on, the switch elements 120 and 123 are turned off, and the switch elements 121 and 122 are turned on. And this state is continued until time t15 which is a 3rd control state. As a result, power is supplied to the high voltage battery B11 on the same principle as in the first control state, and the high voltage battery B11 is charged.

  The control circuit 13 turns on the switch elements 102 and 103 and turns off the switch elements 120 to 123 during the time t15 to t18 in the fourth control state. However, the control circuit 13 turns on the switch elements 121 and 122 during time t16 to t17 during the period of the fourth control state. As a result, the current flowing through the switch element 103 becomes 0 on the same principle as in the second control state. For this reason, when switching from the fourth control state to the first control state, the switch element 103 is turned off at a timing when the current of the switch element 103 becomes 0, so that the surge voltage generated at that time becomes very small.

  Thereafter, the control circuit 13 repeats the first to fourth control states every cycle Ts. As a result, power is continuously supplied to the high voltage battery B11, and the high voltage battery B11 is charged.

  Next, effects of the first embodiment will be described.

  According to the first embodiment, the control method is different from the conventional one, and the first to fourth control states are repeated. In addition, during the period of the second control state, the control circuit 13 can turn on the switch elements 120 and 123 to generate a current in a direction opposite to the current flowing through the switch element 102. Therefore, the current flowing through the switch element 102 can be reduced. Therefore, even when the switch element 102 is turned off when shifting from the second control state to the third control state, the surge voltage generated at that time can be suppressed. In addition, during the period of the fourth control state, the control circuit 13 can turn on the switch elements 121 and 122 to generate a current in a direction opposite to the current flowing through the switch element 103. Therefore, the current flowing through the switch element 103 can be suppressed. Therefore, even when the switch element 103 is turned off when shifting from the fourth control state to the first control state, the surge voltage generated at that time can be suppressed. Thereby, in the power converter device 1 in which the control method is different from the conventional one, the surge voltage can be suppressed.

  According to the first embodiment, when shifting from the second control state to the third control state, the control circuit 13 turns off the switch element 102 when the current flowing through the switch element 102 is zero. Further, when shifting from the fourth control state to the first control state, when the current flowing through the switch element 103 is 0, the control circuit 13 turns off the switch element 103. Therefore, the surge voltage can be reliably suppressed.

  According to the first embodiment, the control circuit 13 is in the period of the second control state based on at least one of the input / output voltage and the input / output current of the first power conversion circuit 10 and the second power conversion circuit 12. The on-time (t12 to t13) of the switch elements 120 and 123 and the on-time (t16 to t17) of the switch elements 121 and 122 during the fourth control state are adjusted. Therefore, even if the input / output voltage and the input / output current of the first power conversion circuit 10 and the second power conversion circuit 12 change, the surge voltage can be reliably suppressed without being affected by the change.

  According to the first embodiment, the transformer 11 has two primary windings 110 and 111 connected in series. The first power conversion circuit 10 includes switch elements 102 and 103, the other end of the switch element 102 is connected to one end of the primary winding 110, and the other end of the switch element 103 is connected to one end of the primary winding 111. Has been. A surge voltage can be suppressed in the power conversion device 1 having the first power conversion circuit 10 and the transformer 11.

  According to the first embodiment, the second power conversion circuit 12 includes switch elements 120 to 123, and the switch elements 120 and 121 connected in series and the switch elements 122 and 123 connected in series are connected to the switch element 120. , 123 are arranged diagonally, and the switch elements 121, 122 are arranged in parallel so as to be arranged diagonally. The series connection point of the switch elements 120 and 121 is connected to one end of the secondary winding 112, and the series connection point of the switch elements 122 and 123 is connected to the other end of the secondary winding 112. A surge voltage can be suppressed in the power conversion device 1 having the second power conversion circuit 12.

(Second Embodiment)
Next, the power converter device of 2nd Embodiment is demonstrated. The power converter of 2nd Embodiment changes the structure of the 1st power converter circuit and transformer in the power converter of 1st Embodiment.

  First, the configuration of the power conversion device according to the second embodiment will be described with reference to FIGS. 9 and 10.

  The power conversion device 2 shown in FIG. 9 is a device that converts the direct current supplied from the low voltage battery B20 into a high voltage direct current, supplies the high voltage battery B21, and charges the high voltage battery B21. The power conversion device 2 includes a first power conversion circuit 20, a transformer 21, a second power conversion circuit 22, and a control circuit 23.

  The first power conversion circuit 20 is a circuit that converts the direct current supplied from the low voltage battery B <b> 20 into alternating current and supplies the alternating current to the transformer 21. The first power conversion circuit 20 includes a capacitor 200, a choke coil 201, and switch elements 202 to 205.

  One end of the capacitor 200 is connected to the positive terminal of the low voltage battery B20, and the other end is connected to the negative terminal of the low voltage battery B20. One end of the choke coil 201 is connected to one end of the capacitor 200, and the other end is connected to the switch elements 202 and 204, respectively.

  The switch elements 202 to 205 are elements that convert direct current supplied from the low-voltage battery B20 into alternating current by being controlled and switched by the control circuit 23. For example, as an FET, as shown in FIG. 10, a capacitor C made of a parasitic capacitance and a parasitic diode D are connected in parallel.

  When the switch elements 202 and 205 (first switch elements) shown in FIG. 9 are turned on, a current is supplied to a primary winding 210 of the transformer 21 described later to generate a unidirectional magnetic flux. When the switch elements 203 and 204 (second switch elements) are turned on, a current is supplied to a primary winding 210 of the transformer 21 described later to generate a magnetic flux in the reverse direction. The switch elements 202 and 203 and the switch elements 204 and 205 are connected in series. The switch elements 202 and 203 connected in series and the switch elements 204 and 205 connected in series are connected in parallel. That is, the switch elements 202 and 203 connected in series and the switch elements 204 and 205 connected in series are arranged such that the switch elements 202 and 205 are diagonally arranged and the switch elements 203 and 204 are arranged diagonally. So that they are connected in parallel. One ends of the switch elements 202 and 204 are connected to the other end of the choke coil 201, and one ends of the switch elements 203 and 205 are connected to the other end of the capacitor 200. The series connection point of the switch elements 202 and 203 and the series connection point of the switch elements 204 and 205 are connected to the transformer 21, respectively. Control ends of the switch elements 202 to 205 are connected to the control circuit 23, respectively.

  The transformer 21 is an element that converts the alternating current supplied from the first power conversion circuit 20 into an alternating current having a predetermined voltage corresponding to the turns ratio in an insulated state and supplies the alternating current to the second power conversion circuit 22. The transformer 21 has a primary winding 210 and a secondary winding 211. One end of the primary winding 210 is connected to the series connection point of the switch elements 202 and 203, and the other end is connected to the series connection point of the switch elements 204 and 205. The secondary winding 211 is connected to the second power conversion circuit 22.

  The second power conversion circuit 22 is a circuit that rectifies and converts the alternating current supplied from the secondary winding 211 of the transformer 21 to direct current, and supplies the direct current to the high voltage battery B21. The second power conversion circuit 22 includes switch elements 220 to 223 and a capacitor 224. The second power conversion circuit 22 has the same configuration as the second power conversion circuit 12 of the first embodiment.

  The control circuit 23 is a circuit that controls the switch elements 202 to 205 and 220 to 223. The control circuit 23 turns on the switch elements 202 and 205, turns off the switch elements 203 and 204, turns on the switch elements 220 and 223, and turns off the switch elements 221 and 222. From the state, the switch elements 202 to 205 are turned on, and the switch elements 220 to 223 are turned off to shift to a second control state. Thereafter, the switch elements 202 and 205 are turned off, the switch elements 203 and 204 are turned on, the switch elements 220 and 223 are turned off, and the switch elements 221 and 222 are turned on. Then, the switch elements 202 to 205 are turned on, and the process proceeds to the fourth control state where the switch elements 220 to 223 are turned off. Thereafter, the first to fourth control states are repeated every cycle Ts. However, the switch elements 220 and 223 are turned on during the second control state, and the switch elements 221 and 222 are turned on during the fourth control state. At that time, based on at least one of the input / output voltage and the input / output current of the first power conversion circuit 20 and the second power conversion circuit 22, the ON time of the switch elements 220 and 223 during the second control state, and The on-time of the switch elements 221 and 222 during the fourth control state is adjusted. The control circuit 23 is connected to the control ends of the switch elements 202 to 205 and 220 to 223, respectively.

  Next, the control method of the power converter of 2nd Embodiment is demonstrated with reference to FIGS.

  As shown in FIG. 11, the control circuit 23 turns on the switch elements 202 and 205, turns off the switch elements 203 and 204, and turns off the switch elements 220 and 205 during the time t20 to t21 in the first control state. 223 is turned on, and the switch elements 221 and 222 are turned off. As a result, as shown in FIG. 12, a current flows from the positive terminal of the low voltage battery B20 to the negative terminal of the low voltage battery B20 via the choke coil 201, the switch element 202, the primary winding 210, and the switch element 205. Flows. At this time, the magnetic energy accumulated in the choke coil 201 is released. As a result, a voltage is induced in the secondary winding 211. As a result, a current flows through a path from one end of the secondary winding 211 to the other end of the secondary winding 211 via the switch element 220, the high voltage battery B21, and the switch element 223. Electric power is supplied to the high voltage battery B21, and the high voltage battery B21 is charged. At this time, electric charge is accumulated in the capacitor 224, and the voltage of the capacitor 224 becomes the same as the voltage of the high voltage battery B21.

  As shown in FIG. 11, the control circuit 23 turns on the switch elements 202 to 205 and turns off the switch elements 220 to 223 during the time t21 to t24 in the second control state. However, the control circuit 23 turns on the switch elements 220 and 223 during the time t22 to t23 during the second control state.

  As shown in FIG. 13, the switching elements 202 and 203 are turned on between times t21 and t22, so that the low voltage battery B20 is connected to the low voltage battery B20 from the positive terminal of the low voltage battery B20 via the choke coil 201 and the switching elements 202 and 203. Current flows through the path leading to the negative electrode end. Further, when the switch elements 204 and 205 are turned on, a current flows through a path from the positive terminal of the low voltage battery B20 to the negative terminal of the low voltage battery B20 via the choke coil 201 and the switch elements 204 and 205. At this time, magnetic energy is accumulated in the choke coil 201. Since the switch elements 202 to 205 are on, one end and the other end of the primary winding 210 are connected. Accordingly, the voltage applied to the primary winding 210 becomes zero. As a result, no voltage is induced in the secondary winding 211.

  As shown in FIG. 14, when the switch elements 220 and 223 are turned on between times t22 and t23, one end and the other end of the capacitor 224 are connected via the switch element 220, the secondary winding 211, and the switch element 223. . The voltage of the capacitor 224 is the same as the voltage of the high voltage battery B21. As a result, a current flows through a path from one end of the capacitor 224 to the other end of the capacitor 224 through the switch element 220, the secondary winding 211, and the switch element 223. As a result, a current flows through a path from one end of the primary winding 210 to the other end of the primary winding 210 via the switch element 202 and the switch element 204. Further, a current flows through a path from one end of the primary winding 210 to the other end of the primary winding 210 via the switch element 203 and the switch element 205. As a result, the current flowing through the switch elements 202 and 205 quickly decreases to zero, and then the direction of the current is reversed and flows in the reverse direction. On the other hand, the current flowing through the switch elements 203 and 204 increases rapidly.

  As shown in FIG. 10, a capacitor C made of a parasitic capacitance is connected to the switch elements 220 and 223 in parallel. When the switch elements 220 and 223 are turned off between times t23 and t24, resonance occurs at a frequency determined by the leakage inductance of the transformer 21, the parasitic capacitance of the switch elements 220 and 223, and the like. As a result, as shown in FIG. 11, the current flowing through the switch elements 202 and 205 becomes zero.

  As shown in FIG. 11, the control circuit 23 turns off the switch elements 202 and 205 and turns on the switch elements 221 and 222 at time t24 when the current flowing through the switch elements 202 and 205 becomes zero. Since the switch elements 202 and 205 are turned off at the timing when the current flowing through the switch elements 202 and 205 becomes 0, the surge voltage generated at that time becomes very small. As a result, the switch elements 202 and 205 are turned off, the switch elements 203 and 204 are turned on, the switch elements 220 and 223 are turned off, and the switch elements 221 and 222 are turned on. And this state is continued until time t25 which is a 3rd control state. As a result, power is supplied to the high voltage battery B21 on the same principle as in the first control state, and the high voltage battery B21 is charged.

  The control circuit 23 turns on the switch elements 202 to 205 and turns off the switch elements 220 to 223 during the time t25 to t28 in the fourth control state. However, the control circuit 23 turns on the switch elements 221 and 222 during time t26 to t27 during the period of the fourth control state. As a result, the current flowing through the switch elements 203 and 204 becomes zero on the same principle as in the second control state. For this reason, when switching from the fourth control state to the first control state, the switch elements 203 and 204 are turned off at the timing when the current flows to the switch elements 203 and 204, so that the surge voltage generated at that time is very small. Become.

  Thereafter, the control circuit 23 repeats the first to fourth control states every cycle Ts. As a result, power is continuously supplied to the high voltage battery B21, and the high voltage battery B21 is charged.

  Next, the effect of the power converter of 2nd Embodiment is demonstrated.

  According to the second embodiment, the control method is different from the conventional one, and the first to fourth control states are repeated. Then, during the period of the second control state, the control circuit 23 can turn on the switch elements 220 and 223 to generate a current in a direction opposite to the current flowing through the switch elements 202 and 205. it can. Therefore, the current flowing through the switch elements 202 and 205 can be reduced. Therefore, even when the switch elements 202 and 205 are turned off when shifting from the second control state to the third control state, the surge voltage generated at that time can be suppressed. In addition, during the period of the fourth control state, the control circuit 23 can turn on the switch elements 221 and 222 to generate a current in a direction opposite to the current flowing through the switch elements 203 and 204. it can. Therefore, the current flowing through the switch elements 203 and 204 can be suppressed. Therefore, even when the switch elements 203 and 204 are turned off when shifting from the fourth control state to the first control state, the surge voltage generated at that time can be suppressed. Thereby, in the power converter device 2 in which the control method is different from the conventional one, the surge voltage can be suppressed.

  According to the second embodiment, when shifting from the second control state to the third control state, when the current flowing through the switch elements 202 and 205 is 0, the control circuit 23 turns off the switch elements 202 and 205. Further, when shifting from the fourth control state to the first control state, when the current flowing through the switch elements 203 and 204 is 0, the control circuit 23 turns off the switch elements 203 and 204. Therefore, the surge voltage can be reliably suppressed.

  According to the second embodiment, the control circuit 23 is in the period of the second control state based on at least one of the input / output voltage and the input / output current of the first power conversion circuit 20 and the second power conversion circuit 22. The on-times (t22 to t23) of the switch elements 220 and 223 and the on-times (t26 to t27) of the switch elements 221 and 222 during the fourth control state are adjusted. Therefore, even if the input / output voltage and the input / output current of the first power conversion circuit 20 and the second power conversion circuit 22 change, the surge voltage can be reliably suppressed without being affected by the change.

  According to the second embodiment, the transformer 21 has one primary winding 210. The first power conversion circuit 20 includes switch elements 202 to 205. The switch elements 202 and 203 connected in series and the switch elements 204 and 205 connected in series are arranged diagonally. In addition, the switch elements 203 and 204 are connected in parallel so as to be arranged diagonally. A series connection point of the switch elements 202 and 203 is connected to one end of the primary winding 210, and a series connection point of the switch elements 204 and 205 is connected to the other end of the primary winding 210. In the power conversion device 2 having the first power conversion circuit 20 and the transformer 21, the surge voltage can be suppressed.

(Third embodiment)
Next, the power converter device of 3rd Embodiment is demonstrated. The power converter of 3rd Embodiment changes the structure of the 1st power converter circuit and 2nd power converter circuit in the power converter of 2nd Embodiment.

  First, the configuration of the power conversion device according to the third embodiment will be described with reference to FIGS. 15 and 16.

  The power conversion device 3 shown in FIG. 15 is a device that converts the direct current supplied from the low-voltage battery B30 into a high-voltage direct current, supplies the high-voltage battery B31, and charges the high-voltage battery B31. The power conversion device 3 includes a first power conversion circuit 30, a transformer 31, a second power conversion circuit 32, and a control circuit 33.

  The first power conversion circuit 30 is a circuit that converts the direct current supplied from the low-voltage battery B30 into an alternating current and supplies the alternating current to the transformer 31. The first power conversion circuit 30 includes a capacitor 300, choke coils 301 and 302, and switch elements 303 and 304.

  One end of the capacitor 300 is connected to the positive terminal of the low voltage battery B30, and the other end is connected to the negative terminal of the low voltage battery B30. One end of the choke coils 301 and 302 is connected to one end of the capacitor 300, and the other end is connected to the switch elements 303 and 304, respectively.

  The switch elements 303 and 304 are elements that convert direct current supplied from the low-voltage battery B30 into alternating current by being controlled and switched by the control circuit 33. For example, it is an FET, and as shown in FIG. 16, a capacitor C made of parasitic capacitance and a parasitic diode D are connected in parallel.

  When the switch element 303 (first switch element) shown in FIG. 15 is turned on, a current is supplied to a primary winding 310 of a transformer 31 described later to generate a magnetic flux in one direction. When the switch element 304 (second switch element) is turned on, the switch element 304 (second switch element) supplies a current to a primary winding 310 of the transformer 31 described later to generate a magnetic flux in the reverse direction. The switch elements 303 and 304 are connected in series. One end of the switch element 303 is connected to the other end of the choke coil 301 and to the transformer 31. One end of the switch element 304 is connected to the other end of the choke coil 302 and to the transformer 31. A series connection point of the switch elements 303 and 304 is connected to the other end of the capacitor 300. The control ends of the switch elements 303 and 304 are connected to the control circuit 33, respectively.

  The transformer 31 is an element that converts the alternating current supplied from the first power conversion circuit 30 into an alternating current having a predetermined voltage corresponding to the turn ratio in an insulated state and supplies the alternating current to the second power conversion circuit 32. The transformer 31 has a primary winding 310 and a secondary winding 311. One end of the primary winding 310 is connected to one end of the switch element 303, and the other end is connected to one end of the switch element 304. The secondary winding 311 is connected to the second power conversion circuit 32.

  The second power conversion circuit 32 is a circuit that rectifies and converts the alternating current supplied from the secondary winding 311 of the transformer 31 to direct current and supplies the direct current to the high voltage battery B31. The second power conversion circuit 32 includes switch elements 320 and 321 and capacitors 322 and 323.

  The switch elements 320 and 321 are elements that are controlled by the control circuit 33 and switch to rectify the alternating current supplied from the secondary winding 311 and convert it into direct current. For example, it is an FET, and as shown in FIG. 16, a capacitor C made of parasitic capacitance and a parasitic diode D are connected in parallel.

  The switch element 320 (third switch element) shown in FIG. 15 rectifies the output of the secondary winding 311 by turning on when the primary winding 310 generates a magnetic flux in one direction. The switch element 321 (fourth switch element) rectifies the output of the secondary winding 311 by turning on when the primary winding 310 generates a magnetic flux in the reverse direction. The switch elements 320 and 321 are connected in series. The capacitors 322 and 323 are connected in series. One end of the switch element 320 is connected to one end of the capacitor 322 and to the positive terminal of the high voltage battery B31. One end of the switch element 321 is connected to one end of the capacitor 323 and is also connected to the negative end of the high voltage battery B31. A series connection point of the switch elements 320 and 321 is connected to one end of the secondary winding 311, and a series connection point of the capacitors 322 and 323 is connected to the other end of the secondary winding 311. The control ends of the switch elements 320 and 321 are connected to the control circuit 33, respectively.

  The control circuit 33 is a circuit that controls the switch elements 303, 304, 320, and 321. The control circuit 33 switches the switch elements 303 and 304 from the first control state in which the switch element 303 is turned on, the switch element 304 is turned off, the switch element 320 is turned on, and the switch element 321 is turned off. Is switched on and the switch elements 320 and 321 are shifted to the second control state. Thereafter, the switch element 303 is turned off, the switch element 304 is turned on, the switch element 320 is turned off, and the switch elements 321 are turned on, and then the switch elements 303 and 304 are turned on. At the same time, the process proceeds to the fourth control state in which the switch elements 320 and 321 are turned off. Thereafter, the first to fourth control states are repeated every cycle Ts. However, the switch element 320 is turned on during the second control state, and the switch element 321 is turned on during the fourth control state. At this time, based on at least one of the input / output voltage and the input / output current of the first power conversion circuit 30 and the second power conversion circuit 32, the on-time of the switch element 320 during the second control state, The on-time of the switch element 321 during the period of the four control states is adjusted. The control circuit 33 is connected to the control ends of the switch elements 303, 304, 320, and 321 respectively.

  Next, the control method of the power converter of 3rd Embodiment is demonstrated with reference to FIGS.

  As shown in FIG. 17, the control circuit 33 turns on the switch element 303, turns off the switch element 304, and turns on the switch element 320 during the time t30 to t31, which is the first control state. The switch element 321 is turned off. As a result, as shown in FIG. 18, a current flows through a path from the positive terminal of the low voltage battery B30 to the negative terminal of the low voltage battery B30 via the choke coil 301 and the switch element 303. Further, a current flows through a path from the positive terminal of the low voltage battery B30 to the negative terminal of the low voltage battery B30 through the choke coil 302, the primary winding 310, and the switch element 303. At this time, magnetic energy is accumulated in the choke coil 301 and magnetic energy accumulated in the choke coil 302 is released. As a result, a voltage is induced in the secondary winding 311. As a result, a current flows through a path from one end of the secondary winding 311 to the other end of the secondary winding 311 via the switch element 320 and the capacitor 322. Electric charge is accumulated in the capacitor 322, and the voltage of the capacitor 322 becomes 1/2 of the voltage of the high voltage battery B31.

  The control circuit 33 turns on the switch elements 303 and 304 and turns off the switch elements 320 and 321 during time t31 to t34, which is the second control state shown in FIG. However, the control circuit 33 turns on the switch element 320 during time t32 to t33 during the second control state.

  As shown in FIG. 19, the switching element 303 is turned on between times t31 and t32, so that the positive terminal of the low voltage battery B30 reaches the negative terminal of the low voltage battery B30 via the choke coil 301 and the switching element 303. Current flows through the path. When the switch element 304 is turned on, a current flows through a path from the positive terminal of the low voltage battery B30 to the negative terminal of the low voltage battery B30 via the choke coil 302 and the switch element 304. At this time, magnetic energy is accumulated in the choke coils 301 and 302. Since the switch elements 303 and 304 are on, one end and the other end of the primary winding 310 are connected. Therefore, the voltage applied to the primary winding 310 becomes zero. As a result, no voltage is induced in the secondary winding 311.

  As shown in FIG. 20, when the switch element 320 is turned on between times t32 and t33, one end and the other end of the capacitor 322 are connected via the secondary winding 311 and the switch element 320. The voltage of the capacitor 322 is ½ of the voltage of the high voltage battery B31. As a result, a current flows through a path from one end of the capacitor 322 to the series connection point of the capacitors 322 and 323 through the switch element 320 and the secondary winding 311. As a result, a current flows through a path from the other end of the primary winding 310 to one end of the primary winding 310 via the switch element 304 and the switch element 303. As a result, as shown in FIG. 17, the current flowing through the switch element 303 decreases rapidly to zero, and then the direction of the current is reversed and flows in the reverse direction. On the other hand, the current flowing through the switch element 304 increases rapidly.

  As shown in FIG. 16, a capacitor C made of a parasitic capacitance is connected in parallel to the switch element 320. When the switch element 320 is turned off between times t33 and t34, resonance occurs at a frequency determined by the leakage inductance of the transformer 31, the parasitic capacitance of the switch element 320, and the like. As a result, as shown in FIG. 17, the current flowing through the switch element 303 becomes zero.

  The control circuit 33 turns off the switch element 303 and turns on the switch element 321 at time t34 when the current flowing through the switch element 303 becomes zero. Since the switch element 303 is turned off at the timing when the current flowing through the switch element 303 becomes 0, the surge voltage generated at that time becomes very small. As a result, the switch element 303 is turned off, the switch element 304 is turned on, the switch element 320 is turned off, and the switch element 321 is turned on. And this state is continued until time t35 which is a 3rd control state.

  The control circuit 33 turns on the switch elements 303 and 304 and turns off the switch elements 320 and 321 during the time t35 to t38 in the fourth control state. However, the control circuit 33 turns on the switch element 321 during time t36 to t37 during the period of the fourth control state. As a result, the current flowing through the switch element 304 becomes zero on the same principle as in the second control state. For this reason, when switching from the fourth control state to the first control state, the switch element 304 is turned off at a timing when the current of the switch element 304 becomes 0, so the surge voltage generated at that time becomes very small.

  Thereafter, the control circuit 33 repeats the first to fourth control states every cycle Ts. As a result, power is continuously supplied to the high voltage battery B31 via the capacitors 322 and 323, and the high voltage battery B31 is charged.

  According to the third embodiment, the control method is different from the conventional one, and the first to fourth control states are repeated. Then, during the period of the second control state, the control circuit 33 turns on the switch element 320, whereby a current in a direction opposite to the current flowing through the switch element 303 can be generated. Therefore, the current flowing through the switch element 303 can be reduced. Therefore, even when the switch element 303 is turned off when shifting from the second control state to the third control state, the surge voltage generated at that time can be suppressed. In addition, during the period of the fourth control state, the control circuit 33 can turn on the switch element 321 to generate a current in the opposite direction to the current flowing through the switch element 304. Therefore, the current flowing through the switch element 304 can be suppressed. Therefore, even when the switch element 304 is turned off when shifting from the fourth control state to the first control state, the surge voltage generated at that time can be suppressed. Thereby, in the power converter device 3 in which the control method is different from the conventional one, the surge voltage can be suppressed.

  According to the third embodiment, when shifting from the second control state to the third control state, the control circuit 33 turns off the switch element 303 when the current flowing through the switch element 303 is zero. Further, when shifting from the fourth control state to the first control state, when the current flowing through the switch element 304 is 0, the control circuit 33 turns off the switch element 304. Therefore, the surge voltage can be reliably suppressed.

  According to the third embodiment, the control circuit 33 is in the period of the second control state based on at least one of the input / output voltage and the input / output current of the first power conversion circuit 30 and the second power conversion circuit 32. The on-time (t32 to t33) of the switch element 320 and the on-time (t36 to t37) of the switch element 321 during the period of the fourth control state are adjusted. Therefore, even if the input / output voltage and the input / output current of the first power conversion circuit 30 and the second power conversion circuit 32 change, the surge voltage can be reliably suppressed without being affected by the change.

  According to the third embodiment, the transformer 31 has one primary winding 310. The first power conversion circuit 30 includes switch elements 303 and 304 connected in series. One end of the switch element 303 is one end of the primary winding 310, and one end of the switch element 304 is the other end of the primary winding 310. Are connected to each. A surge voltage can be suppressed in the power conversion device 3 having the first power conversion circuit 30 and the transformer 31.

  According to the third embodiment, the second power conversion circuit 32 includes switch elements 320 and 321 and capacitors 322 and 323, and capacitors 322 and 323 connected in series with the switch elements 320 and 321 connected in series. Are connected in parallel. A series connection point of the switch elements 320 and 321 is connected to one end of the secondary winding 311, and a series connection point of the capacitors 322 and 323 is connected to the other end of the secondary winding 311. The surge voltage can be suppressed in the power conversion device 3 having the second power conversion circuit 32 as described above.

  In the first to third embodiments, when switching from the second control state to the third control state and when shifting from the fourth control state to the first control state, the switch element of the first power conversion circuit is used. Although an example is given in which the control circuit turns off the switch element when the flowing current is 0, the present invention is not limited to this. When the current flowing through the switch element falls within a predetermined range near 0, the switch element may be turned off. At t12 to t13 shown in FIG. 3, t22 to t23 shown in FIG. 11, and t32 to t33 shown in FIG. 17, when the current flowing through the switch element falls within a predetermined range near 0, the switch element is turned off. Also good. When the direction of the current flowing through the switch element is reversed and reversed, the switch element may be turned off. Also in this case, the surge voltage can be suppressed.

  Incidentally, a parasitic diode is connected in parallel to the switch element. As described above, when the direction of the current flowing through the switch element is reversed and reversed, when the switch element is turned off, the current that has been flowing through the switch element until then flows through the parasitic diode. Therefore, the surge voltage can be reliably suppressed. The same effect can be obtained even if a diode is connected in parallel to the switch element instead of the parasitic diode.

  In the first to third embodiments, examples in which the first power conversion circuit, the transformer, and the second power conversion circuit have predetermined configurations are given, but the present invention is not limited thereto. When the transformer has one primary winding, the first power conversion circuit may be configured as in the second embodiment. When the transformer has two primary windings, the first power conversion circuit may have the configuration in the first embodiment or the configuration in the third embodiment. The second power conversion circuit may have the configuration in the first and second embodiments, or the configuration in the third embodiment. The power conversion device may be configured by combining the first power conversion circuit, the transformer, and the second power conversion circuit of the first to third embodiments. In either case, the same effect can be obtained.

  In the first to third embodiments, an example is given in which a predetermined switch element of the second power conversion circuit is turned on in the first and third control states, but the present invention is not limited to this. Since the parasitic diode is connected in parallel to the switch element, it is not necessary to turn on the switch element in the first and third control states. It can be rectified by a parasitic diode.

  In the first to third embodiments, after a predetermined time has elapsed since the transition to the second control state, and after a predetermined time has elapsed since the transition to the fourth control state, the predetermined switch element of the second power conversion circuit is Although the example which makes it an ON state is given, it is not restricted to this. A predetermined switch element of the second power conversion circuit may be turned on immediately after the transition to the second control state and immediately after the transition to the fourth control state. In this case, the same effect can be obtained.

DESCRIPTION OF SYMBOLS 1 ... Power converter device, 10 ... 1st power converter circuit, 100 ... Capacitor, 101 ... Choke coil, 102 ... Switch element (1st switch element), 103 ... Switch element (Second switch element), 11 ... transformer, 110, 111 ... primary winding, 112 ... secondary winding, 12 ... second power conversion circuit, 120, 123 ... switch Element (third switch element), 121, 122 ... Switch element (fourth switch element), 124 ... Capacitor, 13 ... Control circuit, B10 ... Low voltage battery, B11 ... High voltage Battery

Claims (11)

A transformer (11, 21, 31) having at least one primary winding and one secondary winding;
At least one first switching element (102, 202, 205, 303) connected to the primary winding and supplying a current to the primary winding to generate a magnetic flux in one direction by being turned on; A first switching element (103, 203, 204, 304) that is connected to the primary winding and that is turned on to supply a current to the primary winding to generate a magnetic flux in the reverse direction; 1 power conversion circuit (10, 20, 30);
At least one third switch element (120, 120) connected to the secondary winding and rectifying the output of the secondary winding by turning on when the primary winding generates magnetic flux in one direction. 123, 220, 223, 320), and connected to the secondary winding, and rectifies the output of the secondary winding by turning on when the primary winding generates a magnetic flux in the reverse direction. A second power conversion circuit (12, 22, 32) having at least one fourth switch element (121, 122, 221, 222, 321);
The first switch element is turned on, the second switch element is turned off, the third switch element is turned on, and the fourth switch element is turned off. A second control state in which one switch element and the second switch element are turned on; the first switch element is turned off; the second switch element is turned on; and the third switch element is turned off. , After passing through a third control state for turning on the fourth switch element, a transition is made to a fourth control state for turning on the first switch element and the second switch element. A control circuit (13, 23, 33) for repeating the fourth control state and controlling the fourth switch element from the first switch element;
In a method for controlling a power conversion device comprising:
The control circuit turns on the third switch element during the second control state and turns on the fourth switch element during the fourth control state. Control method of power converter.   When the control circuit shifts from the second control state to the third control state, the current flowing through the first switch element is in the vicinity of 0, or when the direction of the current is reversed and reverses, When the first switch element was turned off and the transition from the fourth control state to the first control state, the current flowing through the second switch element was 0, or the direction of the current was reversed and turned in the reverse direction. The method for controlling a power converter according to claim 1, wherein the second switch element is sometimes turned off.   When the control circuit shifts from the second control state to the third control state, the control circuit turns off the first switch element when the current flowing through the first switch element becomes close to 0, and 3. The control of the power conversion device according to claim 2, wherein, when the control state shifts to the first control state, the second switch element is turned off when a current flowing through the second switch element is 0. 4. Method.   The diode (D) is connected in parallel to the first switch element (102, 202, 205, 303) and the second switch element (103, 203, 204, 304), according to claim 2, The control method of the power converter device of description.   The control circuit turns on the third switch element during the second control state based on at least one of the input / output voltage and the input / output current of the first power conversion circuit and the second power conversion circuit. 5. The method for controlling a power conversion device according to claim 1, wherein the time and the on-time of the fourth switch element during the period of the fourth control state are adjusted. The third switch element (120, 123, 220, 223, 320) and the fourth switch element (121, 122, 221, 222, 321) are diodes (D) connected in parallel,
6. The control circuit according to claim 1, wherein the control circuit does not turn on the third switch element and the fourth switch element in the first control state and the third control state. The control method of the power converter device of description. The transformer (11) has two primary windings (110, 111) connected in series,
The first power conversion circuit (10) has one first switch element (102) and one second switch element (103), and the first switch element is one of the primary windings. The method for controlling a power converter according to claim 1, wherein the second switch element is connected to one end of the other primary winding at one end of the line. The transformer (21) has one primary winding (210),
The first power conversion circuit (20) includes two first switch elements (202, 205) and two second switch elements (203, 204), and two sets of the series connected to each other. The first switch element and the second switch element are configured to be connected in parallel so that the first switch element is disposed diagonally and the second switch element is disposed diagonally. A series connection point of the first switch element and the second switch element is one end of the primary winding, and a series connection point of the other first switch element and the second switch element is the other end of the primary winding. The method for controlling the power conversion device according to claim 1, wherein the power conversion device is connected to the power conversion device. The transformer (31) has one primary winding (310),
The first power conversion circuit (30) has one first switch element (303) and one second switch element (304) connected in series, and the first switch element is the first switch element (303). The method for controlling a power conversion device according to claim 1, wherein the second switch element is connected to one end of a secondary winding, and the other end of the primary winding. .   The second power conversion circuit (12, 22) has two third switch elements (120, 123, 220, 223) and two fourth switch elements (121, 122, 221, 222). In addition, two sets of the third switch element and the fourth switch element connected in series are arranged such that the third switch element is diagonally arranged and the fourth switch element is diagonally arranged. A series connection point of one of the third switch element and the fourth switch element is connected to one end of the secondary winding, and the other third switch element and the fourth switch element are connected in series. The point is connected to the other end of said secondary winding, The control method of the power converter device of any one of Claims 1-9 characterized by the above-mentioned.   The second power conversion circuit (32) includes one third switch element (320), one fourth switch element (321), and two capacitors (322, 323), which are connected in series. The third switch element, the fourth switch element, and two capacitors connected in series are connected in parallel, and the series connection point of the third switch element and the fourth switch element is the secondary 10. The power converter according to claim 1, wherein a series connection point of the two capacitors is connected to one end of the winding and the other end of the secondary winding. Control method.

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