JP2018093620A - Chopper circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chopper circuit capable of suppressing expansion of a failure after a short-circuit failure of a first rectifier or a second rectifier.SOLUTION: This chopper circuit 100 is provided with: a reactor 2; a DC output circuit 1; a capacitor circuit 3; a reverse blocking IGBT 4a which is connected with a positive pole of the capacitor circuit 3, and connected with a positive pole of the DC output circuit 1; a bidirectional IGBT module 6a which is connected in series with the reverse blocking IGBT 4a; a reverse blocking IGBT 4b which is connected with a negative pole of the capacitor circuit 3, and connected with a negative pole of the DC output circuit 1; a bidirectional IGBT module 6b which is connected in series with the reverse blocking IGBT 4b; and a control part 9 which controls on/off of the reverse blocking IGBT 4b when short-circuit of the bidirectional IGBT module 6a is detected, and controls on/off of the reverse blocking IGBT 4a when short-circuit of the bidirectional IGBT module 6b is detected.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a chopper circuit, and more particularly, to a chopper circuit including a reverse blocking conduction control element.

  Conventionally, a chopper circuit including a reverse blocking energization control element is known (for example, see Patent Document 1).

  The chopper circuit described in Patent Document 1 includes a first bidirectional energization control element module and a second bidirectional energization control element module connected in series with each other. The first bidirectional energization control element module includes a first reverse blocking energization control element and a first reverse parallel reverse blocking energization control element connected in antiparallel to the first reverse blocking energization control element. The second bidirectional energization control element module includes a second reverse blocking energization control element and a second reverse parallel reverse blocking energization control element connected in antiparallel to the second reverse blocking energization control element. Further, the chopper circuit is provided with a first capacitor and a second capacitor connected in series with each other. Each of the first capacitor and the second capacitor is connected to both ends of the first bidirectional conduction control element module and the second bidirectional conduction control element module via the first rectification element and the second rectification element. A connection point between the first bidirectional conduction control element module and the second bidirectional conduction control element module and a connection point between the first capacitor and the second capacitor are connected to each other. The chopper circuit is provided with a smoothing reactor, and a DC power source is connected to the first bidirectional energization control element module and the second bidirectional energization control element module via the smoothing reactor. The chopper circuit is configured to boost the voltage of the DC power supply using a smoothing reactor and supply power to the load.

JP 2009-284439 A

  Here, in the chopper circuit described in Patent Document 1, one of the first rectifying element and the second rectifying element may cause a short circuit failure due to a surge voltage (reverse recovery surge) or the like during reverse recovery. . At this time, in the conventional chopper circuit such as the chopper circuit described in Patent Document 1, both the first bidirectional conduction control element module and the second bidirectional conduction control element module are controlled to be turned off. At this time, an OFF signal is given to the first reverse blocking energization control element and the second reverse blocking energization control element which are switches on the forward direction side with respect to the current flow. On the other hand, an ON signal is given to the first reverse parallel reverse blocking energization control element and the second reverse parallel reverse blocking energization control element which are switches on the reverse side with respect to the current flow. The reverse leakage current of the reverse blocking conduction control element is smaller when the reverse blocking conduction control element is turned on, and the reverse breakdown voltage is larger when the reverse blocking conduction control element is turned on. Because.

  However, in the conventional chopper circuit as described in Patent Document 1, for example, when the first rectifier element is short-circuited and the voltage value of the first capacitor is larger than the voltage value of the DC power supply. Even when the first bidirectional energization control element module and the second bidirectional energization control element module are turned off, the current from the first capacitor passes through the short-circuited first rectification element and flows back to the DC power source. Then, a current flows backward from the DC power source to the second bidirectional energization control element module. As described above, there is a problem that the failure expands when the current continues to flow through the short-circuit failure portion of the first rectifier element.

  The present invention has been made to solve the above-described problems, and one object of the present invention is to suppress the expansion of failure after a short-circuit failure of the first rectifying device or the second rectifying device. Is to provide a chopper circuit capable of

  A chopper circuit according to one aspect of the present invention includes a reactor, a DC output circuit, a capacitor circuit connected in parallel to a load, a positive electrode of the capacitor circuit, and a positive electrode of the DC output circuit. The first reverse blocking energization control element, the first rectifying element connected in series with the first reverse blocking energization control element, and the negative electrode of the capacitor circuit and the negative electrode of the DC output circuit A second reverse blocking energization control element, a second rectifying element connected in series with the second reverse blocking energization control element, a short circuit detecting unit for detecting a short circuit between the first rectifying element and the second rectifying element, and a short circuit detecting When the short circuit of the first rectifying element is detected by the control unit, on / off of the second reverse blocking current control element is controlled, and when the short circuit of the second rectifying element is detected by the short circuit detecting unit, By controlling the on-off of the control device, and a control unit to cut off the path of current flow back to the DC output circuit side from the capacitor circuit. “Circuit” generally refers to a conductor connected without termination, but in this specification, “circuit” is a broad term that means “current path” including the presence of termination. It is described as a concept. “ON” means that the first reverse blocking energization control element, the first reverse parallel reverse blocking energization control element, the second reverse blocking energization control element, or the second reverse parallel reverse blocking energization control element is in a forward conduction state. This means that when reverse voltage is applied, the reverse leakage current is reduced to increase the reverse breakdown voltage.

  In the chopper circuit according to one aspect of the present invention, as described above, when a short circuit of the first rectifying element or the second rectifying element is detected, a path of current flowing backward from the capacitor circuit to the DC output circuit side is detected by the control unit. By shutting off, it is possible to suppress a current from flowing to a location where the short circuit failure of the rectifying element. As a result, the expansion of the failure after the failure of the first rectifying device or the second rectifying device can be suppressed.

  The chopper circuit according to the above aspect preferably further includes a voltage detection unit that detects a voltage value of the capacitor circuit, and the control unit is a case where a short circuit of the first rectifier element is detected by the short circuit detection unit and a voltage detection When the voltage value of the capacitor circuit detected by the unit is larger than the voltage value of the positive electrode of the DC output circuit, the on / off of the second reverse blocking conduction control element is controlled, and the short circuit of the second rectifying element is detected by the short circuit detection unit When the voltage value of the capacitor circuit detected by the voltage detection unit is larger than the voltage value of the positive electrode of the DC output circuit, the first reverse blocking energization control element is controlled to be turned on / off. . Here, when the voltage value of the capacitor circuit is larger than the voltage value of the positive electrode of the DC output circuit, the current flows backward from the capacitor circuit to the DC output circuit side. Therefore, when the voltage value of the capacitor circuit is larger than the voltage value of the positive electrode of the DC output circuit, the control unit controls on / off of the first reverse blocking energization control element or the second reverse blocking energization control element, thereby The reverse flow can be appropriately cut.

  In the chopper circuit according to the above aspect, the short-circuit detection unit preferably includes a current detection unit that detects a value and direction of a current between the capacitor circuit and the DC output circuit, and the control unit is When the short circuit of one rectifying element is detected and the voltage value of the capacitor circuit detected by the voltage detection unit is larger than the voltage value of the positive electrode of the DC output circuit, the direction of the current detected by the current detection unit is Based on the inversion, the on / off of the second reverse blocking energization control element is controlled, and the voltage value of the capacitor circuit detected by the voltage detection unit when the short circuit of the second rectifying element is detected by the current detection unit is When the voltage value of the positive electrode of the DC output circuit is larger than the positive voltage value, the on / off of the first reverse blocking energization control element is controlled based on the reverse direction of the current detected by the current detection unit. It is configured so that. According to this configuration, on the basis of the fact that the direction of the current is reversed, the on / off of the first reverse blocking energization control element or the second reverse blocking energization control element is controlled to directly detect the reverse current flow. Therefore, the reverse current flow can be more appropriately cut off.

  In this case, preferably, the control unit detects the short-circuit of the first rectifying element by the current detection unit, and the voltage value of the capacitor circuit detected by the voltage detection unit is higher than the voltage value of the positive electrode of the DC output circuit. When the current is detected, the direction of the current detected by the current detection unit is reversed from the direction of charging the capacitor circuit to the direction of discharging the capacitor circuit. When the short circuit of the second rectifying element is detected by the current detection unit and the voltage value of the capacitor circuit detected by the voltage detection unit is larger than the voltage value of the positive electrode of the DC output circuit, the current detection unit detects On the basis of the fact that the current direction is reversed from the charging direction of the capacitor circuit to the discharging direction of the capacitor circuit, the on / off of the first reverse blocking conduction control element is controlled. It is configured to. With this configuration, it is possible to directly detect and control the backflow of current from the capacitor circuit to the DC output circuit side, so that the backflow of current from the capacitor circuit to the DC output circuit side can be controlled more appropriately. Can be cut.

  In the chopper circuit according to the above aspect, the chopper circuit is preferably a step-up chopper circuit, and includes a first reverse parallel reverse blocking energization control element connected in reverse parallel to the first reverse blocking energization control element, and a second reverse blocking. And a second reverse parallel reverse blocking energization control element connected in reverse parallel to the energization control element, the reactor being connected in series with the DC output circuit, the first reverse blocking energization control element and the second reverse blocking The energization control element is connected to both ends of the DC output circuit via the reactor, and the capacitor circuit has a positive electrode connected to the cathode of the first rectifying element and a negative electrode connected to the first reverse blocking energization control element and the first. 2 The first capacitor connected to the connection point with the reverse blocking conduction control element and the positive electrode are connected to the connection point between the first reverse blocking conduction control element and the second reverse blocking conduction control element, and negative Includes a second capacitor connected to the anode of the second rectifying element, and the control unit turns on the second reverse blocking energization control element when a short circuit of the first rectifying element is detected by the short circuit detecting unit. When the second reverse parallel reverse blocking energization control element is turned off and the short circuit detecting unit detects a short circuit of the second rectifying element, the first reverse blocking energization control element is turned on and the first reverse parallel reverse blocking energization control is performed. By turning off the element, the path of the current that flows backward from the capacitor circuit to the DC output circuit side is cut off. If comprised in this way, when the short circuit of a 1st rectifier is detected by the short circuit detection part, the electric current from a 1st capacitor to a direct-current output circuit side will be carried out by turning off the 2nd reverse parallel reverse blocking electricity control element. Is reversely interrupted by the second reverse parallel reverse blocking energization control element. At this time, by turning on the second reverse blocking energization control element, the reverse leakage current of the second reverse blocking energization control element to which a reverse voltage is applied can be reduced, the reverse breakdown voltage can be improved, and the failure can be suppressed. Further, when a short circuit of the second rectifying element is detected by the short circuit detection unit, the reverse flow of the current from the second capacitor to the DC output circuit side is reduced by turning off the first reverse parallel reverse blocking conduction control element. 1 is blocked by the reverse parallel reverse blocking energization control element. At this time, by turning on the first reverse blocking energization control element, the reverse leakage current of the first reverse blocking energization control element to which the reverse voltage is applied can be reduced, the reverse breakdown voltage can be improved, and the failure can be suppressed.

  In this case, preferably, a voltage detection unit that detects the voltage value of the capacitor circuit is further provided, and the control unit detects the short circuit of the first rectifying element by the short circuit detection unit and detects the first value detected by the voltage detection unit. When the voltage value of one capacitor is equal to or less than the voltage value of the positive electrode of the DC output circuit, the second reverse parallel reverse blocking energization control element is turned on, and the short circuit detecting unit detects the short circuit of the second rectifying element and the voltage When the voltage value of the second capacitor detected by the detection unit is equal to or less than the voltage value of the positive electrode of the DC output circuit, the first reverse parallel reverse blocking energization control element is turned on. With this configuration, when the short circuit of the first rectifying element is detected and the voltage value of the first capacitor is equal to or lower than the voltage value of the positive electrode of the DC output circuit, the second reverse parallel reverse voltage applied with the reverse voltage is applied. By turning on the blocking energization control element, the reverse leakage current of the second reverse parallel reverse blocking energization control element can be reduced, the reverse breakdown voltage can be improved, and the failure can be suppressed. When the voltage value of the first capacitor is equal to or less than the voltage value of the positive electrode of the DC output circuit, the current does not flow backward through the DC output circuit. Therefore, even if the second reverse parallel reverse blocking conduction control element is turned on, the first rectification is performed. The expansion of device failure can be suppressed. Further, when a short circuit of the second rectifying element is detected and the voltage value of the second capacitor is equal to or lower than the voltage value of the positive electrode of the DC output circuit, the first reverse parallel reverse blocking energization control element to which the reverse voltage is applied is By turning on, the reverse leakage current of the first reverse parallel reverse blocking energization control element can be reduced, the reverse breakdown voltage can be improved, and the failure can be suppressed. Note that when the voltage value of the second capacitor is equal to or less than the voltage value of the positive electrode of the DC output circuit, the current does not reversely flow through the DC output circuit. Therefore, even if the first reverse parallel reverse blocking conduction control element is turned on, the second rectification is performed. The expansion of device failure can be suppressed.

  When the first rectifying element is short-circuited, the second reverse blocking conduction control element is turned on and the second reverse parallel reverse blocking conduction control element is turned off. When the second rectifying element is short-circuited, the first reverse blocking conduction control element is turned on. In the chopper circuit that turns off the first reverse parallel reverse blocking energization control element, preferably, the control unit detects the second reverse parallel reverse blocking energization control element when the short circuit detecting unit detects a short circuit of the first rectifying element. The second reverse blocking energization control element is turned off when turning on the second reverse blocking energization control element when turning off the second reverse parallel reverse blocking energization control element. When the first reverse parallel reverse blocking energization control element is turned on, the first reverse blocking energization control element is turned off, and when the first reverse parallel reverse blocking energization control element is turned off, the first reverse parallel reverse blocking energization control element is turned off. Reverse blocking current control element It is configured to turn on. If comprised in this way, by interrupting | blocking the flow of an electric current by turning off one of a 1st (2nd) reverse blocking energization control element and a 1st (2nd) reverse parallel reverse blocking energization control element, While expanding the failure of the short circuit location can be suppressed, the reverse leakage current can be reduced by turning on the other.

  In the chopper circuit according to the above aspect, the chopper circuit is preferably a step-up chopper circuit, the reactor is connected in series with the DC output circuit, and the first reverse blocking energization control element and the second reverse blocking energization control element Is connected to both ends of the DC output circuit via a reactor, and the capacitor circuit has a positive electrode connected to the cathode of the first rectifying element and a negative electrode connected to the first reverse blocking conduction control element and the second reverse blocking. The third capacitor connected to the connection point with the energization control element, the positive electrode is connected to the connection point between the first reverse blocking energization control element and the second reverse blocking energization control element, and the negative electrode is the second rectification A fourth capacitor connected to the anode of the element, and the control unit turns on the second reverse blocking energization control element when the short circuit detecting unit detects a short circuit of the first rectifying element. When a short circuit of the second rectifying element is detected by the short circuit detection unit, the first reverse blocking energization control element is turned on to cut off the path of the current flowing backward from the capacitor circuit to the DC output circuit side. ing. With this configuration, even if the first rectifying element is short-circuited and the current is going to flow backward from the third capacitor to the DC output circuit, and the reverse voltage is applied to the second reverse blocking conduction control element, (2) Since the reverse leakage current is reduced and the reverse breakdown voltage is increased by turning on the reverse blocking energization control element, it is possible to suppress the current from flowing to the location where the first rectifying element is short-circuited. Further, even when the second rectifying element is short-circuited and a reverse voltage is applied to the first reverse blocking energization control element as a result of the current flowing from the fourth capacitor to the DC output circuit, the first reverse blocking energization control element is turned on. Therefore, similarly to the first rectifying element, the reverse leakage current is reduced and the reverse breakdown voltage is increased. As a result, the expansion of the failure of the first rectifying element or the second rectifying element is suppressed.

  In this case, preferably, the control unit further includes a voltage detection unit that detects a voltage value of the capacitor circuit, and the first detection unit detected by the voltage detection unit when the short circuit detection unit detects a short circuit of the first rectifier element. When the voltage value of the three capacitors is equal to or less than the voltage value of the positive electrode of the DC output circuit, the second reverse blocking energization control element is turned off, and the short-circuit detection unit detects a short circuit of the second rectifier element and the voltage detection unit When the voltage value of the fourth capacitor detected by the above is equal to or less than the voltage value of the positive electrode of the DC output circuit, the first reverse blocking conduction control element is turned off. With this configuration, when the voltage value of the third capacitor is equal to or lower than the voltage value of the positive electrode of the DC output circuit, only the third capacitor is charged from the DC output circuit by turning off the second reverse blocking conduction control element. Therefore, it is possible to suppress a current from flowing in the direction in which the large current flows to the failure portion of the first rectifier element. When the first rectifier element is short-circuited and the voltage value of the third capacitor is equal to or lower than the voltage value of the positive electrode of the DC output circuit, the current does not flow back to the DC output circuit. Even if the element is turned off, the expansion of the failure of the first rectifying element can be suppressed. Further, when the voltage value of the fourth capacitor is equal to or lower than the voltage value of the positive electrode of the DC output circuit, the first reverse blocking conduction control element is turned off, so that the current flows in the direction of charging only the fourth capacitor from the DC output circuit. It can suppress that a big electric current flows and flows into the fault location of a 2nd rectifier. When the second rectifier element is short-circuited and the voltage value of the fourth capacitor is equal to or lower than the voltage value of the positive electrode of the DC output circuit, the current does not flow back to the DC output circuit. Even if the element is turned off, the expansion of the failure of the second rectifying element can be suppressed.

  In the chopper circuit according to the above aspect, the chopper circuit is preferably a step-down chopper circuit, and a third reverse parallel reverse blocking energization control element connected in reverse parallel to the first reverse blocking energization control element, and a second reverse blocking A fourth anti-parallel reverse blocking energization control element connected in anti-parallel to the energization control element, the reactor is connected in series with the capacitor circuit, and the first rectification element and the second rectification element include the reactor The DC output circuit includes a first DC power supply having a positive electrode connected to the first reverse blocking energization control element and a negative electrode connected to the anode of the first rectifier element. And a second DC power source in which the positive electrode is connected to the negative electrode of the first DC power source and the cathode of the second rectifying element, and the negative electrode is connected to the second reverse blocking conduction control element, The control unit turns on the second reverse blocking energization control element and turns off the fourth reverse parallel reverse blocking energization control element when the short circuit detecting unit detects a short circuit of the first rectifying element. When a short circuit of the two rectifying elements is detected, the first reverse blocking energization control element is turned on and the third reverse parallel reverse blocking energization control element is turned off, so that the current flowing backward from the capacitor circuit to the DC output circuit side is reduced. It is configured to block the route. If comprised in this way, when the short circuit of a 1st rectification element is detected by the short circuit detection part, by turning off a 4th reverse parallel reverse blocking electricity control element, the electric current from a capacitor circuit to a 2nd DC power supply The reverse flow is interrupted by the fourth reverse parallel reverse blocking energization control element. At this time, by turning on the second reverse blocking energization control element, the reverse leakage current of the second reverse blocking energization control element to which a reverse voltage is applied can be reduced, the reverse breakdown voltage can be improved, and the failure can be suppressed. Further, when a short circuit of the second rectifying element is detected by the short circuit detection unit, turning off the third reverse parallel reverse blocking energization control element causes a reverse current flow from the capacitor circuit to the first DC power source. It is interrupted by the reverse parallel reverse blocking energization control element. At this time, by turning on the first reverse blocking energization control element, the reverse leakage current of the third reverse blocking energization control element to which a reverse voltage is applied can be reduced, the reverse breakdown voltage can be improved, and the failure can be suppressed.

  In this case, preferably, a voltage detection unit that detects the voltage value of the capacitor circuit is further provided, and the control unit detects the short circuit of the first rectifying element by the short circuit detection unit and detects the capacitor detected by the voltage detection unit. When the voltage value of the circuit is equal to or less than the voltage value of the positive electrode of the second DC power source, the fourth reverse parallel reverse blocking energization control element is turned on, and the short circuit detecting unit detects the short circuit of the second rectifying element and the voltage When the voltage value of the capacitor circuit detected by the detection unit is equal to or lower than the voltage value of the positive electrode of the first DC power supply, the third reverse parallel reverse blocking energization control element is turned on. According to this configuration, when the short circuit of the first rectifying element is detected and the voltage value of the capacitor circuit is equal to or lower than the voltage value of the positive electrode of the second DC power supply, the fourth reverse parallel reverse operation is applied. By turning on the blocking energization control element, the reverse leakage current of the fourth reverse parallel reverse blocking energization control element can be reduced, the reverse breakdown voltage can be improved, and the failure can be suppressed. When the voltage value of the capacitor circuit is equal to or less than the voltage value of the positive electrode of the second DC power supply, the current does not flow back to the second DC power supply. Therefore, even if the fourth reverse parallel reverse blocking conduction control element is turned on, the first The expansion of the failure of the rectifying element can be suppressed. When a short circuit of the second rectifier element is detected and the voltage value of the capacitor circuit is equal to or lower than the voltage value of the positive electrode of the first DC power supply, a third reverse parallel reverse blocking energization control element to which a reverse voltage is applied is provided. By turning on, the reverse leakage current of the third reverse parallel reverse blocking energization control element can be reduced, the reverse breakdown voltage can be improved, and the failure can be suppressed. When the voltage value of the capacitor circuit is equal to or less than the voltage value of the positive electrode of the first DC power supply, the current does not flow backward to the first DC power supply. Therefore, even if the third reverse parallel reverse blocking conduction control element is turned on, the second The expansion of the failure of the rectifying element can be suppressed.

  When the first rectifying element is short-circuited, the second reverse blocking conduction control element is turned on and the fourth reverse parallel reverse blocking conduction control element is turned off. When the second rectifying element is short-circuited, the first reverse blocking conduction control element is turned on. In the chopper circuit that turns off the third reverse parallel reverse blocking energization control element, preferably, when the short circuit detecting unit detects a short circuit of the first rectifying element, the control unit detects the fourth reverse parallel reverse blocking energization control element. The second reverse blocking energization control element is turned off when turning on, and the second reverse blocking energization control element is turned on when turning off the fourth reverse parallel reverse blocking energization control element. When the third reverse parallel reverse blocking energization control element is turned on, the first reverse blocking energization control element is turned off, and when the third reverse parallel reverse blocking energization control element is turned off, the first reverse parallel reverse blocking energization control element is turned off. Reverse blocking current control element It is configured to turn on. If comprised in this way, by interrupting | blocking the flow of an electric current by turning off one of a 1st (2nd) reverse blocking energization control element and a 3rd (4th) reverse parallel reverse blocking energization control element, While expanding the failure of the short circuit location can be suppressed, the reverse leakage current can be reduced by turning on the other.

  In the chopper circuit according to the above aspect, preferably, the chopper circuit is a step-down chopper circuit, the reactor is connected in series with the capacitor circuit, and the first rectifier element and the second rectifier element are capacitors via the reactor. The DC output circuit is connected to both ends of the circuit, and includes a third DC power source having a positive electrode connected to the first reverse blocking energization control element and a negative electrode connected to the anode of the first rectifying element, Is connected to the negative electrode of the third DC power source and the cathode of the second rectifier element, and the fourth DC power source is connected to the second reverse blocking conduction control element. When the short circuit of the first rectifying element is detected by the second reverse blocking energization control element is turned on, and when the short circuit detecting unit detects the short circuit of the second rectifying element, the first reverse blocking By turning on the electric control device is configured to block the path of the current flowing back from the capacitor circuit to the DC output circuit side. According to this configuration, even when the first rectifying element is short-circuited and the current tries to flow backward from the capacitor circuit to the fourth DC power source, and the reverse voltage is applied to the second reverse blocking conduction control element, (2) Since the reverse leakage current is reduced and the reverse breakdown voltage is increased by turning on the reverse blocking energization control element, it is possible to suppress the current from flowing to the location where the first rectifying element is short-circuited. Further, even when the second rectifying element is short-circuited and a reverse voltage is applied to the first reverse blocking energization control element in order to reverse the current from the capacitor circuit to the third DC power supply, the first reverse blocking energization control element is turned on. Therefore, the reverse leakage current is reduced and the reverse breakdown voltage is increased. By these, the expansion of the failure of the 1st rectifier or the 2nd rectifier can be controlled.

  In this case, preferably, a voltage detection unit that detects the voltage value of the capacitor circuit is further provided, and the control unit detects the short circuit of the first rectifying element by the short circuit detection unit and detects the capacitor detected by the voltage detection unit. When the voltage value of the circuit is equal to or less than the voltage value of the positive electrode of the fourth DC power supply, the second reverse blocking energization control element is turned off, and the short-circuit detection unit detects a short circuit of the second rectifier element and the voltage detection unit When the voltage value of the capacitor circuit detected by the above is equal to or lower than the voltage value of the positive electrode of the third DC power supply, the first reverse blocking conduction control element is turned off. With this configuration, when the voltage value of the capacitor circuit is equal to or less than the voltage value of the positive electrode of the fourth DC power supply, the capacitor circuit is charged from the fourth DC power supply by turning off the second reverse blocking conduction control element. Therefore, the expansion of the failure of the first rectifying element can be suppressed. In this case, since the current does not flow backward from the capacitor circuit to the fourth DC power supply, even if the second reverse blocking energization control element is turned off, the expansion of the failure of the first rectifying element can be suppressed. Further, when the voltage value of the capacitor circuit is equal to or lower than the voltage value of the positive electrode of the third DC power supply, charging the capacitor circuit from the third DC power supply is suppressed by turning off the first reverse blocking energization control element. Therefore, the expansion of the failure of the second rectifying element can be suppressed. In this case, since the current does not flow backward from the capacitor circuit to the third DC power supply, even if the first reverse blocking conduction control element is turned off, the expansion of the failure of the second rectifying element can be suppressed.

  According to the present invention, as described above, it is possible to provide a chopper circuit capable of suppressing the expansion of a failure after a short-circuit failure of the first rectifying device or the second rectifying device.

It is the figure which showed the structure of the chopper circuit by 1st Embodiment of this invention. It is a figure for demonstrating the flow of operation control of the chopper circuit by 1st Embodiment of this invention. It is the figure which showed the structure of the chopper circuit by 2nd Embodiment of this invention. It is a figure for demonstrating the flow of operation control of the chopper circuit by 2nd Embodiment of this invention. It is the figure which showed the structure of the chopper circuit by 3rd Embodiment of this invention. It is a figure for demonstrating the flow of operation control of the chopper circuit by 3rd Embodiment of this invention. It is the figure which showed the structure of the chopper circuit by 4th Embodiment of this invention. It is a figure for demonstrating the flow of operation control of the chopper circuit by 4th Embodiment of this invention.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the drawings.

[First Embodiment]
First, the configuration of the chopper circuit 100 according to the first embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 shows an electric circuit diagram of the chopper circuit 100.

(Configuration of Chopper Circuit of First Embodiment)
As shown in FIG. 1, the chopper circuit 100 includes a DC output circuit 1. The chopper circuit 100 is configured to boost the voltage of the DC output circuit 1 and apply it to the load 101. The chopper circuit 100 is configured as a so-called three-level boost chopper circuit. “Circuit” generally refers to a conductor connected without termination, but in this specification, “circuit” is a broad term that means “current path” including the presence of termination. It is described as a concept.

  The DC output circuit 1 is constituted by a DC power supply or a capacitor. And when the DC output circuit 1 is comprised with the capacitor | condenser, AC power supply or DC power supply may be provided separately separately. For example, when a rotating electrical machine is provided as an AC power supply, the chopper circuit 100 is configured to regenerate power from the rotating electrical machine to a load 101 (for example, a battery).

  The load 101 may be constituted by, for example, a battery (DC power supply), or may be constituted by a combination of an inverter including a plurality of switching elements and an electric motor. When the load 101 is configured by a battery, the load 101 is configured to charge power (regenerative power) from the DC output circuit 1. When the load 101 includes an electric motor, the load 101 is configured to consume power and drive.

  The chopper circuit 100 includes a reactor 2. The reactor 2 is connected in series with the DC output circuit 1.

  The chopper circuit 100 includes a capacitor circuit 3 connected in parallel to a load 101. Capacitor circuit 3 includes a capacitor 3a and a capacitor 3b connected in series. Specifically, the capacitor 3 a and the capacitor 3 b are connected to both ends of the load 101. That is, the positive electrode of the capacitor 3a and the negative electrode of the capacitor 3b are respectively connected to both ends of the load 101, and the negative electrode of the capacitor 3a and the positive electrode of the capacitor 3b are connected to each other. The capacitor 3a and the capacitor 3b are examples of the “first capacitor” and the “second capacitor” in the claims, respectively.

  The chopper circuit 100 includes a reverse blocking IGBT unit 4 connected to both ends of the DC output circuit 1 via the reactor 2. The reverse blocking IGBT unit 4 includes a reverse blocking IGBT 4 a connected to the positive electrode of the capacitor 3 a and connected to the positive electrode of the DC output circuit 1. The reverse blocking IGBT 4a is connected to the positive electrode of the capacitor 3a via a bidirectional IGBT module 6a described later. The reverse blocking IGBT unit 4 includes a reverse blocking IGBT 4b connected to the negative electrode of the capacitor 3b and connected to the negative electrode of the DC output circuit 1. The reverse blocking IGBT 4b is connected to the negative electrode of the capacitor 3b via a bidirectional IGBT module 6b described later. The reverse blocking IGBT 4a and the reverse blocking IGBT 4b are examples of the “first reverse blocking energization control element” and the “second reverse blocking energization control element” in the claims, respectively.

  Specifically, one end of reactor 2 and the collector of reverse blocking IGBT 4a are connected. The emitter of the reverse blocking IGBT 4a is connected to the collector of the reverse blocking IGBT 4b. The emitter of the reverse blocking IGBT 4b and the negative electrode of the DC output circuit 1 are connected. Further, the positive electrode of the DC output circuit 1 and the other end of the reactor 2 are connected.

  The chopper circuit 100 includes a reverse parallel reverse blocking IGBT unit 5 connected in reverse parallel to the reverse blocking IGBT unit 4. The reverse parallel reverse blocking IGBT unit 5 includes an reverse parallel reverse blocking IGBT 5a connected in reverse parallel to the reverse blocking IGBT 4a. The reverse parallel reverse blocking IGBT unit 5 includes an reverse parallel reverse blocking IGBT 5b connected in reverse parallel to the reverse blocking IGBT 4b. The reverse parallel reverse blocking IGBT 5a and the reverse parallel reverse blocking IGBT 5b are examples of the “first reverse parallel reverse blocking energization control element” and the “second reverse parallel reverse blocking energization control element”, respectively.

  The chopper circuit 100 includes a rectifying element unit 6 connected in series with the reverse blocking IGBT unit 4 and the reverse parallel reverse blocking IGBT unit 5. The rectifying element unit 6 includes a bidirectional IGBT module 6a connected in series with the reverse blocking IGBT 4a and the reverse parallel reverse blocking IGBT 5a. The bidirectional IGBT module 6a includes a reverse blocking IGBT 4c and an reverse parallel reverse blocking IGBT 5c connected in reverse parallel to the reverse blocking IGBT 4c. The rectifying element unit 6 includes a bidirectional IGBT module 6b connected in series with the reverse blocking IGBT 4b and the reverse parallel reverse blocking IGBT 5b. The bidirectional IGBT module 6b includes a reverse blocking IGBT 4d and an antiparallel reverse blocking IGBT 5d connected in reverse parallel to the reverse blocking IGBT 4d. The bidirectional IGBT module 6a and the bidirectional IGBT module 6b are examples of the “first rectifying element” and the “second rectifying element” in the claims, respectively.

  Further, the reverse blocking IGBT 4a and the reverse parallel reverse blocking IGBT 5a constitute a bidirectional IGBT module 6c. Further, the reverse blocking IGBT 4b and the reverse parallel reverse blocking IGBT 5b constitute a bidirectional IGBT module 6d.

  The capacitor 3a has a positive electrode connected to the cathode of the bidirectional IGBT module 6a and a negative electrode connected to a connection point A between the reverse blocking IGBT 4a and the reverse blocking IGBT 4b. Specifically, the emitter of the antiparallel reverse blocking IGBT 5c and the positive electrode of the capacitor 3a are connected. The collector of the reverse blocking IGBT 4a and the collector of the reverse parallel reverse blocking IGBT 5c are connected.

  The capacitor 3b has a positive electrode connected to the connection point A and a negative electrode connected to the anode of the bidirectional IGBT module 6b. Specifically, the negative electrode of the capacitor 3b and the collector of the antiparallel reverse blocking IGBT 5d are connected. Note that the emitter of the reverse parallel reverse blocking IGBT 5d is connected to the emitter of the reverse blocking IGBT 4b.

  The chopper circuit 100 includes a voltage detection unit 7 that detects the voltage value of the capacitor circuit 3. The voltage detector 7 is connected to the positive electrode of the capacitor 3a and the positive electrode of the capacitor 3b, and is configured to detect the voltage value Vc1 of the positive electrode of the capacitor 3a and the voltage value Vc2 of the positive electrode of the capacitor 3b. Yes. And the voltage detection part 7 is comprised so that the detected voltage value Vc1 and Vc2 may be transmitted to the control part 9 mentioned later.

  The chopper circuit 100 includes a current detection unit 8 that detects the value and direction of the current between the capacitor circuit 3 and the DC output circuit 1. Specifically, the current detection unit 8 can detect the direction in which the current flowing through the reactor 2 flows (the direction of the arrow C1 and the arrow C2 in FIG. 1) and the current value IL of the current flowing through the reactor 2. It is configured. The current detection unit 8 is configured to transmit the detected current flowing direction and the current value IL to the control unit 9 described later. The current detection unit 8 is an example of the “short circuit detection unit” in the claims.

  The chopper circuit 100 includes a control unit 9 that receives signals from the voltage detection unit 7 and the current detection unit 8 and controls on / off of each reverse blocking IGBT. The control unit 9 is an example of the “short circuit detection unit” in the claims.

<Configuration of control unit>
The control unit 9 is connected to the gates of the reverse blocking IGBT 4a, reverse blocking IGBT 4b, reverse blocking IGBT 4c, reverse blocking IGBT 4d, reverse parallel reverse blocking IGBT 5a, reverse parallel reverse blocking IGBT 5b, reverse parallel reverse blocking IGBT 5c, and reverse parallel reverse blocking IGBT 5d. It is configured to control on / off of the eight IGBT elements. The control unit 9 controls the voltage ratio (boost) and current value (into the reactor 2) with respect to the load 101 of the chopper circuit 100 by controlling the ON / OFF (switching operation) time ratio (duty) of the reverse blocking IGBT 4a and the reverse blocking IGBT 4b. The flowing current value IL) is adjusted (controlled). Further, the reverse parallel reverse blocking IGBT 5a and the reverse parallel reverse blocking IGBT 5b are turned on so that the reverse breakdown voltage is increased and the reverse leakage current is reduced because a reverse voltage is applied when the reverse blocking IGBT 4a and the reverse blocking IGBT 4b are turned off. It will be in the state of. Further, the reverse blocking IGBT 4c and the reverse blocking IGBT 4d are turned off, and the reverse parallel reverse blocking IGBT 5c and the reverse parallel reverse blocking IGBT 5d are turned on, whereby the bidirectional IGBT module 6a and the bidirectional IGBT module 6b are turned on. Indicates a rectifying function.

  The control unit 9 is configured to detect a short circuit of the bidirectional IGBT module 6a and a short circuit of the bidirectional IGBT module 6b based on the detection result of the current detection unit 8. Specifically, the control unit 9 determines whether the bidirectional IGBT module 6a or the bidirectional IGBT module 6b has a current flowing through the reactor 2 regardless of the ON / OFF operation of the reverse blocking IGBT 4a and the reverse blocking IGBT 4b. Control to determine that a short circuit has occurred.

  For example, the control unit 9 compares the current value IL with a predetermined threshold value ILt stored in advance, and detects a short circuit when the current value IL exceeds the predetermined threshold value ILt. In this case, the control unit 9 associates the time point when the current value IL exceeds a predetermined threshold value ILt with the operation state of the bidirectional IGBT module 6c and the bidirectional IGBT module 6d, and determines the bidirectional IGBT module 6a or It is configured to detect (determine) which of the bidirectional IGBT modules 6b is short-circuited. The predetermined threshold value ILt is not limited to one value, and a plurality of values may be provided.

  Here, when the short-circuit failure of the bidirectional IGBT module 6a and the voltage value Vc1 of the capacitor 3a is larger than the voltage value Va of the DC output circuit 1, the capacitor 3a, the short-circuited bidirectional IGBT module 6a, the reactor 2 The current flows backward in the order of the DC output circuit 1 and the bidirectional IGBT module 6d. At this time, when the reverse parallel reverse blocking IGBT 5b is turned on, a current may flow through a short-circuit fault location of the bidirectional IGBT module 6a, which may cause an increase in failure. Further, even when the bidirectional IGBT module 6b is short-circuited, when the voltage value Vc2 of the capacitor 3b is larger than the voltage value Va of the DC output circuit 1 and when the reverse parallel reverse blocking IGBT 5a is turned on, the bidirectional IGBT This causes an increase in the failure of the module 6b. The information on the voltage value Va may be stored in the chopper circuit 100 in advance, or may be configured to be acquired by providing a voltage detection unit.

  Therefore, in the first embodiment, the control unit 9 controls on / off of the reverse blocking IGBT 4b and the reverse parallel reverse blocking IGBT 5b when a short circuit of the bidirectional IGBT module 6a is detected. Moreover, the control part 9 controls ON / OFF of reverse blocking IGBT4a and reverse parallel reverse blocking IGBT5a, when the short circuit of bidirectional | two-way IGBT module 6b is detected. As a result, the control unit 9 interrupts the path of the current that flows backward from the capacitor circuit 3 to the DC output circuit 1 side.

  Specifically, the control unit 9 determines that the voltage value Vc1 of the capacitor 3a detected by the voltage detection unit 7 when the short circuit of the bidirectional IGBT module 6a is detected is greater than the voltage value Va of the positive electrode of the DC output circuit 1. Is also turned off (set to the disconnected state), and the reverse blocking IGBT 4b is turned on. On the other hand, when the short-circuit of the bidirectional IGBT module 6b is detected and the voltage value Vc2 of the capacitor 3b detected by the voltage detection unit 7 is larger than the voltage value Va of the positive electrode of the DC output circuit 1, The parallel reverse blocking IGBT 5a is turned off (disconnected), and the reverse blocking IGBT 4a is turned on.

  In the first embodiment, when the short-circuit of the bidirectional IGBT module 6a is detected, the control unit 9 turns off the reverse blocking IGBT 4b and turns the reverse parallel reverse blocking IGBT 5b on when turning the reverse parallel reverse blocking IGBT 5b on. When turning off, reverse blocking IGBT 4b is turned on. Further, when a short circuit of the bidirectional IGBT module 6b is detected, the reverse blocking IGBT 4a is turned off when the reverse parallel reverse blocking IGBT 5a is turned on, and the reverse blocking IGBT 4a is turned on when the reverse parallel reverse blocking IGBT 5a is turned off. It is configured. That is, neither the reverse parallel reverse blocking IGBT 5b nor the reverse blocking IGBT 4b is turned on or off. Further, neither the reverse parallel reverse blocking IGBT 5a nor the reverse blocking IGBT 4a is turned on or off.

  In the first embodiment, the control unit 9 determines that the voltage value Vc1 of the capacitor 3a detected by the voltage detection unit 7 when the short circuit of the bidirectional IGBT module 6a is detected is the positive voltage of the DC output circuit 1. When larger than the value Va, the reverse parallel reverse blocking IGBT 5b is turned off and the reverse blocking IGBT 4b is turned on based on the fact that the direction of the current detected by the current detection unit 8 is reversed. Further, the control unit 9 detects that the short-circuit of the bidirectional IGBT module 6b is detected and the voltage value Vc2 of the capacitor 3b detected by the voltage detection unit 7 is larger than the voltage value Va of the positive electrode of the DC output circuit 1. In addition, based on the fact that the direction of the current detected by the current detector 8 is reversed, the reverse parallel reverse blocking IGBT 5a is turned off and the reverse blocking IGBT 4a is turned on.

  As a result, when the bidirectional IGBT module 6a is short-circuited, the reverse parallel reverse blocking IGBT 5b is turned on until the current flows backward from the capacitor 3a to the DC output circuit 1. As a result, it is possible to reduce the reverse leakage current of the reverse parallel reverse blocking IGBT 5b. Similarly, when the bidirectional IGBT module 6b is short-circuited, the reverse leakage current of the reverse parallel reverse blocking IGBT 5a can be reduced.

  Specifically, the control unit 9 determines that the voltage value Vc1 of the capacitor 3a detected by the voltage detection unit 7 when the short circuit of the bidirectional IGBT module 6a is detected is greater than the voltage value Va of the positive electrode of the DC output circuit 1. Is larger than the direction in which the current detected by the current detector 8 flows from the direction in which the capacitor 3a is charged (in the direction of arrow C1 in FIG. 1) to the direction in which the capacitor 3a is discharged (in the direction of arrow C2 in FIG. 1). Based on the result (at the time of inversion), the reverse parallel reverse blocking IGBT 5b is switched from on (forward conducting state) to off (disconnected state), and the reverse blocking IGBT 4b is switched from off (disconnected state) to on (forward conducting state). It is comprised so that control to switch to may be performed. At this time, the control unit 9 puts the bidirectional IGBT module 6c in the forward direction off state (the reverse blocking IGBT 4a is off and the reverse parallel reverse blocking IGBT 5a is on).

  Thereby, when a short circuit of the bidirectional IGBT module 6a is detected, when the reverse current flows to the reverse parallel reverse blocking IGBT 5b, the reverse parallel reverse blocking IGBT 5b is in a disconnected state. No current flows. Further, since the reverse blocking IGBT 4b is turned off while the capacitor 3a is being charged, a large current flows through the bidirectional IGBT module 6a due to the current flowing in the direction in which only the capacitor 3a is charged from the DC output circuit 1. It is possible to suppress this.

  Further, when the reverse parallel reverse blocking IGBT 5b is blocking the current to flow backward, a reverse leakage current flows through the reverse blocking IGBT 4b. Since the reverse leakage current is large when the reverse blocking IGBT 4b is in the OFF state, there is a possibility that the failure will increase due to the current flowing through the location where the short-circuit failure has occurred in the bidirectional IGBT module 6a. In addition, since the reverse breakdown voltage is small in the off state, the breakdown causes a current to flow, and there is a possibility that the reverse blocking IGBT 4b or the bidirectional IGBT module 6a may expand. Therefore, the reverse blocking voltage is increased and the reverse leakage current is reduced by turning on the reverse blocking IGBT 4b.

  Further, the control unit 9 detects that the short-circuit of the bidirectional IGBT module 6b is detected and the voltage value Vc2 of the capacitor 3b detected by the voltage detection unit 7 is larger than the voltage value Va of the positive electrode of the DC output circuit 1. In addition, the direction in which the current detected by the current detection unit 8 flows is reversed from the direction in which the capacitor 3b is charged (in the direction of arrow C1 in FIG. 1) to the direction in which the capacitor 3b is discharged (in the direction of arrow C2 in FIG. 1). Based on (at the time of reversal), the reverse parallel reverse blocking IGBT 5a is switched from on (forward conduction state) to off (disconnected state), and the reverse blocking IGBT 4a is switched from off (disconnected state) to on (forward conduction state). Is configured to do. At this time, the control unit 9 puts the bidirectional IGBT module 6d in the forward direction off state (the reverse blocking IGBT 4b is off and the reverse parallel reverse blocking IGBT 5b is on).

  Thereby, when a short circuit of the bidirectional IGBT module 6b is detected, when the reverse current flows to the reverse parallel reverse blocking IGBT 5a, the reverse parallel reverse blocking IGBT 5a is in a disconnected state. No current flows. Further, since the reverse blocking IGBT 4a is turned off while the capacitor 3b is being charged, a large current flows through the bidirectional IGBT module 6b due to the current flowing in the direction in which only the capacitor 3b is charged from the DC output circuit 1. Can be suppressed.

  Further, when the reverse parallel reverse blocking IGBT 5a is blocking the current to flow backward, a reverse leakage current flows through the reverse blocking IGBT 4a. For this reason, the reverse blocking IGBT 4a is turned on to increase the reverse breakdown voltage and reduce the reverse leakage current.

  In the first embodiment, the control unit 9 determines that the voltage value of the capacitor 3 a detected by the voltage detection unit 7 when the short circuit of the bidirectional IGBT module 6 a is detected is the voltage value of the positive electrode of the DC output circuit 1. In the following case, since the current does not flow backward from the capacitor 3a, the reverse parallel reverse blocking IGBT 5b is turned on. At this time, by turning off the reverse blocking IGBT 4b, it is possible to suppress a large current from flowing in the bidirectional IGBT module 6a due to charging only the capacitor 3a from the DC output circuit 1.

  In addition, when the short-circuit of the bidirectional IGBT module 6b is detected and the voltage value of the capacitor 3b detected by the voltage detection unit 7 is equal to or less than the voltage value of the positive electrode of the DC output circuit 1, the control unit 9 Since the current does not flow backward from the capacitor 3b, the reverse parallel reverse blocking IGBT 5a is turned on. At this time, the reverse blocking IGBT 4a is turned off to charge only the capacitor 3b from the DC output circuit 1. It is possible to suppress a large current from flowing through the bidirectional IGBT module 6b due to the above.

(Operation of boost chopper circuit)
<Operation during normal operation>
Next, with reference to FIG. 1, the operation | movement at the time of normal driving | operation of the chopper circuit 100 by 1st Embodiment is demonstrated. The operation of the chopper circuit 100 is executed by the control process of the control unit 9.

  First, when the reverse blocking IGBT 4a is turned on and the reverse blocking IGBT 4b is turned off, a current flows in the order of the DC output circuit 1, the reactor 2, the reverse blocking IGBT 4a, the capacitor 3b, and the reverse parallel reverse blocking IGBT 5d.

  When the reverse blocking IGBT 4a is turned off and the reverse blocking IGBT 4b is turned on, current flows in the order of the DC output circuit 1, the reactor 2, the reverse parallel reverse blocking IGBT 5c, the capacitor 3a, and the reverse blocking IGBT 4b.

  When the reverse blocking IGBT 4a is turned on and the reverse blocking IGBT 4b is turned on, current flows in the order of the DC output circuit 1, the reactor 2, the reverse blocking IGBT 4a, and the reverse blocking IGBT 4b.

  When the reverse blocking IGBT 4a is turned off and the reverse blocking IGBT 4b is turned off, the current flows in the order of the DC output circuit 1, the reactor 2, the reverse parallel reverse blocking IGBT 5c, the capacitor 3a, the capacitor 3b, and the reverse parallel reverse blocking IGBT 5d. Flowing.

  In the chopper circuit 100, each period (duty ratio) of the above operation is controlled by the control unit 9, and the above operation is repeated to boost the voltage from the voltage of the DC output circuit 1 (the power is converted). ) Electric power is supplied to the load 101.

<Operation when short circuit is detected>
Next, with reference to FIG. 1 and FIG. 2, the operation at the time of short circuit detection of the chopper circuit 100 according to the first embodiment will be described. The operation of the chopper circuit 100 is executed by the control process of the control unit 9.

  As shown in FIG. 2, first, in step S1, it is determined whether or not a short circuit of the bidirectional IGBT module 6a is detected. When the short circuit of the bidirectional IGBT module 6a is not detected, the process proceeds to step S2, and when the short circuit of the bidirectional IGBT module 6a is detected, the process proceeds to step S3.

  In step S2, it is determined whether or not a short circuit of the bidirectional IGBT module 6b has been detected. When the short circuit of the bidirectional IGBT module 6b is detected, the process proceeds to step S8. When the short circuit of the bidirectional IGBT module 6b is not detected, the operation of the chopper circuit 100 when the short circuit is detected is terminated.

  In addition, it is possible to detect a short circuit during the operation during the normal operation by repeating the steps S1 and S2 during the operation during the normal operation.

  Further, in step S3 which proceeds when a short circuit of the bidirectional IGBT module 6a is detected in step S1, it is determined whether or not the voltage value Vc1 of the capacitor 3a is larger than the positive voltage value Va of the DC output circuit 1. If the voltage value Vc1 is larger than the voltage value Va, the process proceeds to step S4. If the voltage value Vc1 is equal to or less than the voltage value Va, the process proceeds to step S7.

  In step S4, it is determined whether or not the direction of the current flowing through the reactor 2 is the direction in which the capacitor 3a is charged. That is, it is determined whether the direction of the current flowing through the reactor 2 is the direction in which the capacitor 3a is charged (in the direction of arrow C1 in FIG. 1) or the direction in which the capacitor 3a is discharged (in the direction of arrow C2). Then, if the direction of the current flowing through the reactor 2 is a direction for charging the capacitor 3a, the process proceeds to step S5. If the direction of the current flowing through the reactor 2 is not a direction for charging the capacitor 3a, the process proceeds to step S6.

  In step S5, both reverse blocking IGBT 4a and reverse blocking IGBT 4b are turned off. At this time, since reverse voltage is applied to the reverse parallel reverse blocking IGBT 5a and the reverse parallel reverse blocking IGBT 5b, each is turned on as in the normal operation. As a result, the bidirectional IGBT module 6c and the bidirectional IGBT module 6d are turned off in the forward direction. Here, as shown in FIG. 1, even when the bidirectional IGBT module 6a has a short circuit failure, the capacitor 3a is charged for a while (DC output circuit 1, reactor 2, bidirectional IGBT module 6a having a short circuit failure). , The capacitor 3a, the capacitor 3b, and the reverse parallel reverse blocking IGBT 5d in this order), the resonance circuit of the DC output circuit 1, the capacitor 3a, the capacitor 3b, and the reactor 2 is obtained. When the reverse blocking IGBT 4a is turned on, the capacitor 3a is short-circuited and discharged, and a large current flows through the failed portion of the bidirectional IGBT module 6a. Moreover, it becomes a resonant circuit of the DC output circuit 1, the capacitor 3b, and the reactor 2, and the voltage of the capacitor 3b is charged to a voltage higher than that during normal operation. When the reverse blocking IGBT 4b is turned on, a resonance circuit of the DC output circuit 1, the capacitor 3a, and the reactor 2 is formed, and the voltage of the capacitor 3a is charged to a voltage higher than that during normal operation. The current flowing through the failure location of the IGBT module 6a is also large. When both the reverse blocking IGBT 4a and the reverse blocking IGBT 4b are turned on, the capacitor 3a is short-circuited and discharged, and the DC output circuit 1 is short-circuited via the reactor 2 to increase the current. Therefore, both the reverse blocking IGBT 4a and the reverse blocking IGBT 4b are turned off.

  In step S5, it is difficult to stop the current flowing through the bidirectional IGBT module 6a by turning off the antiparallel reverse blocking IGBT 5d because the current of the reactor 2 is to be cut off. Therefore, the reverse parallel reverse blocking IGBT 5d is kept on while the current of the reactor 2 flows in the direction of charging the capacitor 3a.

  Then, it returns to step S4. That is, steps S4 and S5 are repeated until the direction of the current flowing through the reactor 2 is not in the direction of charging the capacitor 3a, and the direction of the current flowing through the reactor 2 is reversed from the direction of charging the capacitor 3a to the direction of discharging. At the time, proceed to step S6. The time point when the capacitor 3a is reversed from the charging direction to the discharging direction is a time point when the current starts to flow backward.

  In step S6, the bidirectional IGBT module 6c is turned off in the forward direction, while the bidirectional IGBT module 6d is turned off in the reverse direction. That is, the reverse blocking IGBT 4b is turned on and the reverse parallel reverse blocking IGBT 5b is turned off. As a result, the current that tries to reversely flow in the order of the capacitor 3a, the short-circuited bidirectional IGBT module 6a, the reactor 2, and the DC output circuit 1 does not flow. Thereafter, the operation at the time of short circuit detection of the chopper circuit 100 is terminated.

  In step S7, which proceeds when the voltage value Vc1 is equal to or lower than the voltage value Va in step S3, the bidirectional IGBT module 6c and the bidirectional IGBT module 6d are both turned off in the forward direction (the reverse blocking IGBT 4a is turned off and the reverse parallel reverse blocking IGBT 5a is turned on). ON, reverse blocking IGBT 4b is OFF, and reverse parallel reverse blocking IGBT 5b is ON). In this case, since the current does not substantially flow backward, both the bidirectional IGBT module 6c and the bidirectional IGBT module 6d are turned off in the forward direction, whereby the operation of the chopper circuit 100 is stopped. Thereafter, the operation at the time of short circuit detection of the chopper circuit 100 is terminated.

  Then, in step S8 that proceeds when a short circuit of the bidirectional IGBT module 6b is detected in step S2, it is determined whether or not the voltage value Vc2 of the capacitor 3b is larger than the positive voltage value Va of the DC output circuit 1. When the voltage value Vc2 is larger than the voltage value Va, the process proceeds to step S9, and when the voltage value Vc2 is equal to or less than the voltage value Va, the process proceeds to step S12.

  In step S9, it is determined whether or not the direction of the current flowing through the reactor 2 is the direction in which the capacitor 3b is charged. If the direction of the current flowing through the reactor 2 is the direction for charging the capacitor 3b, the process proceeds to step S10. If the direction of the current flowing through the reactor 2 is not the direction for charging the capacitor 3b, the process proceeds to step S11.

  In step S10, the bidirectional IGBT module 6c and the bidirectional IGBT module 6d are both forward off (reverse blocking IGBT 4a is off, reverse parallel reverse blocking IGBT 5a is on, reverse blocking IGBT 4b is off, and reverse parallel reverse blocking IGBT 5b is on. ). Thereafter, the process returns to step S9.

  In step S11, the bidirectional IGBT module 6c is turned off in the reverse direction (the reverse blocking IGBT 4a is turned on and the reverse parallel reverse blocking IGBT 5a is turned off), and the bidirectional IGBT module 6d is turned off in the forward direction (the reverse blocking IGBT 4b is turned off). Off, and the reverse parallel reverse blocking IGBT 5b is turned on). As a result, the current that tries to reversely flow in the order of the capacitor 3b, the bidirectional IGBT module 6c, the reactor 2, the DC output circuit 1, and the short-circuited bidirectional IGBT module 6b does not flow. Thereafter, the operation at the time of short circuit detection of the chopper circuit 100 is terminated.

  Further, in step S12, which proceeds when the voltage value Vc2 is equal to or lower than the voltage value Va in step S8, the bidirectional IGBT module 6c and the bidirectional IGBT module 6d are both turned off in the forward direction (the reverse blocking IGBT 4a is turned off and the reverse parallel reverse blocking IGBT 5a is turned off). ON, reverse blocking IGBT 4b is OFF, and reverse parallel reverse blocking IGBT 5b is ON). Thereafter, the operation at the time of short circuit detection of the chopper circuit 100 is terminated.

(Effect of 1st Embodiment)
In the first embodiment, the following effects can be obtained.

  In the first embodiment, as described above, when the short circuit of the bidirectional IGBT module 6a is detected, the control unit 9 controls on / off of the reverse blocking IGBT 4b, and the short circuit of the bidirectional IGBT module 6b is detected. In this case, the chopper circuit 100 is configured so that the path of the current flowing backward from the capacitor circuit 3 to the DC output circuit 1 side is blocked by the control unit 9 by controlling the on / off of the reverse blocking IGBT 4a. Thereby, it can suppress that an electric current flows into the location where the short-circuit failure of bidirectional IGBT module 6a or bidirectional IGBT module 6b. As a result, the expansion of the failure after the failure of the bidirectional IGBT module 6a or the bidirectional IGBT module 6b can be suppressed.

  Further, in the first embodiment, as described above, when the short circuit of the bidirectional IGBT module 6a is detected by the control unit 9, the voltage value of the capacitor circuit 3 detected by the voltage detection unit 7 is the DC output circuit. When the voltage value of the positive electrode of 1 is larger, the on / off of the reverse blocking IGBT 4b is controlled. When the short circuit of the bidirectional IGBT module 6b is detected and the voltage value of the capacitor circuit 3 detected by the voltage detection unit 7 is larger than the voltage value of the positive electrode of the DC output circuit 1, the reverse blocking IGBT 4a Chopper circuit 100 is configured to control on / off. Here, when the voltage value of the capacitor circuit 3 is larger than the voltage value of the positive electrode of the DC output circuit 1, the current flows backward from the capacitor circuit 3 to the DC output circuit 1 side. Accordingly, when the voltage value of the capacitor circuit 3 is larger than the voltage value of the positive electrode of the DC output circuit 1, the reverse blocking current is appropriately cut off by controlling the reverse blocking IGBT 4a or the reverse blocking IGBT 4b by the control unit 9. can do.

  In the first embodiment, as described above, when the control unit 9 detects the short-circuit of the bidirectional IGBT module 6 a by the current detection unit 8 and the voltage of the capacitor circuit 3 detected by the voltage detection unit 7. When the value is larger than the voltage value of the positive electrode of the DC output circuit 1, on / off of the reverse blocking IGBT 4b is controlled based on the reverse direction of the current detected by the current detection unit 8. When the short-circuit of the bidirectional IGBT module 6b is detected by the current detection unit 8 and when the voltage value of the capacitor circuit 3 detected by the voltage detection unit 7 is larger than the voltage value of the positive electrode of the DC output circuit 1 The chopper circuit 100 is configured to control the on / off of the reverse blocking IGBT 4a based on the fact that the direction of the current detected by the current detection unit 8 is reversed. As a result, by controlling on / off of the reverse blocking IGBT 4a or reverse blocking IGBT 4b based on the reverse of the direction of the current, it is possible to directly detect and control the reverse flow of the current. Can be cut more appropriately.

  In the first embodiment, as described above, when the control unit 9 detects the short-circuit of the bidirectional IGBT module 6 a by the current detection unit 8 and the voltage of the capacitor circuit 3 detected by the voltage detection unit 7. When the value is larger than the voltage value of the positive electrode of the DC output circuit 1, the direction of the current detected by the current detection unit 8 is reversed from the direction of charging the capacitor circuit 3 to the direction of discharging the capacitor circuit 3. Based on this, ON / OFF of the reverse blocking IGBT 4b is controlled. When the short-circuit of the bidirectional IGBT module 6b is detected by the current detection unit 8 and when the voltage value of the capacitor circuit 3 detected by the voltage detection unit 7 is larger than the voltage value of the positive electrode of the DC output circuit 1 The chopper circuit controls the on / off of the reverse blocking IGBT 4a based on the fact that the direction of the current detected by the current detection unit 8 is reversed from the direction of charging the capacitor circuit 3 to the direction of discharging the capacitor circuit 3. 100 is configured. As a result, it is possible to directly detect and control the backflow of current from the capacitor circuit 3 to the DC output circuit 1 side, so that the backflow of current from the capacitor circuit 3 to the DC output circuit 1 side can be controlled more appropriately. Can be cut.

  Further, in the first embodiment, as described above, when the short circuit of the bidirectional IGBT module 6a is detected, the control unit 9 turns on the reverse blocking IGBT 4b and turns off the reverse parallel reverse blocking IGBT 5b. When a short circuit of the bidirectional IGBT module 6b is detected, the reverse blocking IGBT 4a is turned on and the reverse parallel reverse blocking IGBT 5a is turned off, whereby a current path flowing backward from the capacitor circuit 3 to the DC output circuit 1 side is established. The chopper circuit 100 is configured to cut off. Thereby, when a short circuit of the bidirectional IGBT module 6a is detected, the reverse parallel reverse blocking IGBT 5b is turned off, whereby the reverse current flow from the capacitor 3a to the DC output circuit 1 side is blocked by the reverse parallel reverse blocking IGBT 5b. Is done. At this time, by turning on the reverse blocking IGBT 4b, the reverse leakage current of the reverse blocking IGBT 4b to which the reverse voltage is applied can be reduced, the reverse breakdown voltage can be improved, and the failure can be suppressed. Further, when a short circuit of the bidirectional IGBT module 6b is detected, the reverse parallel reverse blocking IGBT 5a is turned off, whereby the reverse current flow from the capacitor 3b to the DC output circuit 1 is blocked by the reverse parallel reverse blocking IGBT 5a. The At this time, by turning on the reverse blocking IGBT 4a, the reverse leakage current of the reverse blocking IGBT 4a to which a reverse voltage is applied can be reduced, the reverse breakdown voltage can be improved, and the failure can be suppressed.

  In the first embodiment, as described above, when the short circuit of the bidirectional IGBT module 6 a is detected by the control unit 9 and the voltage value of the capacitor 3 a detected by the voltage detection unit 7 is the DC output circuit 1. When the voltage value is less than or equal to the positive electrode voltage value, the reverse parallel reverse blocking IGBT 5b is turned on. When the short-circuit of the bidirectional IGBT module 6b is detected and the voltage value of the capacitor 3b detected by the voltage detection unit 7 is equal to or lower than the voltage value of the positive electrode of the DC output circuit 1, the reverse parallel reverse blocking IGBT 5a is set. The chopper circuit 100 is configured to be turned on.

  Thereby, when the short circuit of the bidirectional IGBT module 6a is detected and the voltage value of the capacitor 3a is equal to or lower than the voltage value of the positive electrode of the DC output circuit 1, the reverse parallel reverse blocking IGBT 5b to which a reverse voltage is applied is turned on. Thereby, the reverse leakage current of the reverse parallel reverse blocking IGBT 5b can be reduced, the reverse breakdown voltage can be improved, and the failure can be suppressed. When the voltage value of the capacitor 3a is equal to or less than the voltage value of the positive electrode of the DC output circuit 1, current does not flow back to the DC output circuit 1, so even if the reverse parallel reverse blocking IGBT 5b is turned on, the bidirectional IGBT module 6a The expansion of failure can be suppressed. When a short circuit of the bidirectional IGBT module 6b is detected and the voltage value of the capacitor 3b is equal to or lower than the voltage value of the positive electrode of the DC output circuit 1, the reverse parallel reverse blocking IGBT 5a to which a reverse voltage is applied is turned on. Thus, the reverse leakage current of the reverse parallel reverse blocking IGBT 5a can be reduced, the reverse breakdown voltage can be improved, and the failure can be suppressed. Note that when the voltage value of the capacitor 3b is equal to or less than the voltage value of the positive electrode of the DC output circuit 1, the current does not flow backward to the DC output circuit 1, so even if the reverse parallel reverse blocking IGBT 5a is turned on, the bidirectional IGBT module 6b The expansion of failure can be suppressed.

  In the first embodiment, as described above, when the short-circuit of the bidirectional IGBT module 6a is detected, the control unit 9 turns off the reverse blocking IGBT 4b and turns the reverse blocking IGBT 4b off when turning on the reverse parallel reverse blocking IGBT 5b. When the parallel reverse blocking IGBT 5b is turned off, the reverse blocking IGBT 4b is turned on. When a short circuit of the bidirectional IGBT module 6b is detected, the reverse blocking IGBT 4a is turned off when the reverse parallel reverse blocking IGBT 5a is turned on, and the reverse blocking IGBT 4a is turned on when the reverse parallel reverse blocking IGBT 5a is turned off. Next, the chopper circuit 100 is configured. As a result, the current flow is cut off by turning off one of the reverse blocking IGBT 4a (reverse blocking IGBT 4b) and the reverse parallel reverse blocking IGBT 5a (reverse parallel reverse blocking IGBT 5b), thereby suppressing the expansion of the failure at the short circuit location. In addition, the reverse leakage current can be reduced by turning on the other.

[Second Embodiment]
Next, the configuration of the chopper circuit 200 according to the second embodiment will be described with reference to FIGS. In the chopper circuit 200 of the second embodiment, the antiparallel reverse blocking IGBT 5a and the antiparallel reverse blocking IGBT 5b are omitted from the configuration of the chopper circuit 100 of the first embodiment. Further, unlike the first embodiment in which the bidirectional IGBT module is provided as the rectifying element, a diode is provided as the rectifying element. In addition, about the structure same as the said 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  The configuration of the chopper circuit 200 according to the second embodiment will be described with reference to FIG. FIG. 3 shows an electric circuit diagram of the chopper circuit 200.

(Configuration of Chopper Circuit According to Second Embodiment)
As shown in FIG. 3, the chopper circuit 200 includes a capacitor circuit 13. Capacitor circuit 13 includes a capacitor 13a and a capacitor 13b. The capacitor 13a and the capacitor 13b are configured similarly to the capacitor 3a and the capacitor 3b of the first embodiment, respectively. The capacitor 13a and the capacitor 13b are examples of the “third capacitor” and the “fourth capacitor” in the claims, respectively.

  The chopper circuit 200 includes a reverse blocking IGBT unit 14. The reverse blocking IGBT unit 14 includes a reverse blocking IGBT 14a and a reverse blocking IGBT 14b. The reverse blocking IGBT 14a and the reverse blocking IGBT 14b are configured similarly to the reverse blocking IGBT 4a and the reverse blocking IGBT 4b of the first embodiment, respectively. The reverse blocking IGBT 14a and the reverse blocking IGBT 14b are examples of the “first reverse blocking energization control element” and the “second reverse blocking energization control element” in the claims, respectively.

  The chopper circuit 200 includes a rectifying element unit 16 connected in series with the reverse blocking IGBT unit 14. The rectifying element unit 16 includes a diode 16a connected in series with the reverse blocking IGBT 14a. The rectifying element unit 16 includes a diode 16b connected in series with the reverse blocking IGBT 14b. The diode 16a and the diode 16b are examples of the “first rectifying element” and the “second rectifying element” in the claims, respectively.

  The cathode of the diode 16 a is connected to the positive electrode of the capacitor 13 a of the capacitor circuit 13. The anode of the diode 16 b is connected to the negative electrode of the capacitor 13 b of the capacitor circuit 13.

<Operation when short circuit is detected>
Next, with reference to FIG. 3 and FIG. 4, the operation | movement at the time of short circuit detection of the chopper circuit 200 by 2nd Embodiment is demonstrated. The operation of the chopper circuit 200 is executed by the control process of the control unit 9a. The control unit 9a is an example of the “short circuit detection unit” in the claims.

  As shown in FIG. 4, it is determined in step S21 whether or not a short circuit of the diode 16a has been detected. If the short circuit of the diode 16a is not detected, the process proceeds to step S22. If the short circuit of the diode 16a is detected, the process proceeds to step S3.

  In step S22, it is determined whether or not a short circuit of the diode 16b has been detected. When the short circuit of the diode 16b is detected, the process proceeds to step S28. When the short circuit of the diode 16b is not detected, the operation of the chopper circuit 200 when the short circuit is detected is terminated.

  In addition, it is possible to detect a short circuit during the operation during the normal operation by repeating the steps S21 and S22 during the operation during the normal operation.

  Further, in step S23 which proceeds when the short circuit of the diode 16a is detected in step S21, it is determined whether or not the voltage value Vc1 of the capacitor 13a is larger than the positive voltage value Va of the DC output circuit 1. When the voltage value Vc1 is larger than the voltage value Va, the process proceeds to step S24, and when the voltage value Vc1 is equal to or less than the voltage value Va, the process proceeds to step S27.

  Then, in step S24, it is determined whether or not the direction of the current flowing through the reactor 2 is a direction for charging the capacitor 13a. Then, when the direction of the current flowing through the reactor 2 is a direction for charging the capacitor 13a, the process proceeds to step S25, and when the direction of the current flowing through the reactor 2 is not a direction for charging the capacitor 13a, the process proceeds to step S26.

  In step S25, the reverse blocking IGBT 14a and the reverse blocking IGBT 14b are both turned off. Thus, by turning off the reverse blocking IGBT 14b, it is possible to suppress a large current from flowing to the failure location of the diode 16a due to the current flowing in the direction in which only the capacitor 13a is charged from the DC output circuit 1. It is.

  Thereafter, the process returns to step S24. That is, steps S24 and S25 are repeated until the direction of the current flowing through the reactor 2 is not in the direction of charging the capacitor 13a, and the direction of the current flowing through the reactor 2 is reversed from the direction of charging the capacitor 13a to the direction of discharging. At the time, proceed to step S26.

  In step S26, the reverse blocking IGBT 14b is turned on. At this time, the reverse breakdown voltage of the reverse blocking IGBT 14b is improved, and the reverse leakage current hardly flows. At this time, the reverse blocking IGBT 14a is turned off. Thereafter, the operation at the time of short circuit detection of the chopper circuit 200 is terminated.

  Further, in step S27 that proceeds when the voltage value Vc1 is equal to or lower than the voltage value Va in step S23, both the reverse blocking IGBT 14a and the reverse blocking IGBT 14b are turned off. In this case, since the current does not substantially flow backward, both the reverse blocking IGBT 14a and the reverse blocking IGBT 14b are turned off, and the operation of the chopper circuit 200 is stopped. Thereafter, the operation at the time of short circuit detection of the chopper circuit 200 is terminated.

  Then, in step S28 that proceeds when the short circuit of the diode 16b is detected in step S22, it is determined whether or not the voltage value Vc2 of the capacitor 13b is larger than the voltage value Va of the positive electrode of the DC output circuit 1. If the voltage value Vc2 is greater than the voltage value Va, the process proceeds to step S29. If the voltage value Vc2 is equal to or less than the voltage value Va, the process proceeds to step S32.

  In step S29, it is determined whether or not the direction of the current flowing through the reactor 2 is the direction in which the capacitor 13b is charged. If the direction of the current flowing through the reactor 2 is the direction for charging the capacitor 13b, the process proceeds to step S30. If the direction of the current flowing through the reactor 2 is not the direction for charging the capacitor 13b, the process proceeds to step S31.

  In step S30, the reverse blocking IGBT 14a and the reverse blocking IGBT 14b are both turned off. Thereafter, the process returns to step S29. Thereby, by turning off the reverse blocking IGBT 14a, it is possible to suppress a large current from flowing to the failure portion of the diode 16b due to the current flowing in the direction in which only the capacitor 13b is charged from the DC output circuit 1. It is.

  In step S31, the reverse blocking IGBT 14a is turned on. At this time, the reverse breakdown voltage of the reverse blocking IGBT 14a is improved, and the reverse leakage current hardly flows. At this time, the reverse blocking IGBT 14b is turned off. As a result, the current that tries to reversely flow in the order of the capacitor 13b, the reverse blocking IGBT 14a, the reactor 2, the DC output circuit 1, and the shorted diode 16b does not flow. Thereafter, the operation at the time of short circuit detection of the chopper circuit 200 is terminated.

  Further, in step S32 which proceeds when the voltage value Vc2 is equal to or lower than the voltage value Va in step S28, both the reverse blocking IGBT 14a and the reverse blocking IGBT 14b are turned off. Thereafter, the operation at the time of short circuit detection of the chopper circuit 200 is terminated.

  The other configuration of the chopper circuit 200 according to the second embodiment is the same as that of the chopper circuit 100 according to the first embodiment.

(Effect of 2nd Embodiment)
In the second embodiment, the following effects can be obtained.

  In the second embodiment, as described above, the control unit 9a turns on the reverse blocking IGBT 14b when the short circuit of the diode 16a is detected, and turns on the reverse blocking IGBT 14a when the short circuit of the diode 16b is detected. By doing so, the path of the current flowing backward from the capacitor circuit 13 to the DC output circuit 1 side is cut off. As a result, even when the diode 16a is short-circuited and the current is going to flow backward from the capacitor 13a to the DC output circuit 1, and the reverse voltage is applied to the reverse blocking IGBT 14b, the reverse leakage current is turned on by turning on the reverse blocking IGBT 14b. Becomes smaller and the reverse breakdown voltage becomes higher, so that it is possible to suppress the current from flowing to the location where the diode 16a is short-circuited. Even if the diode 16b is short-circuited and a reverse voltage is applied to the reverse blocking IGBT 14a as a result of the current flowing from the capacitor 13b to the DC output circuit 1, the reverse blocking IGBT 14a is turned on, so that the reverse leakage current is reduced and the reverse breakdown voltage is reduced. Becomes higher. Accordingly, it is possible to suppress the expansion of the failure of the diode 16a or the diode 16b.

  Further, in the second embodiment, as described above, when the short circuit of the diode 16a is detected by the control unit 9a and the voltage value of the capacitor 13a detected by the voltage detection unit 7 is the positive polarity of the DC output circuit 1. When the reverse blocking IGBT 14b is turned off when the voltage value is equal to or lower than the voltage value, the voltage value of the capacitor 13b detected by the voltage detection unit 7 when the short circuit of the diode 16b is detected is equal to or lower than the positive voltage value of the DC output circuit 1. In such a case, the reverse blocking IGBT 14a is turned off. As a result, when the voltage value of the capacitor 13a is equal to or less than the voltage value of the positive electrode of the DC output circuit 1, by turning off the reverse blocking IGBT 14b, a current flows from the DC output circuit 1 in the direction of charging only the capacitor 13a. Therefore, it is possible to suppress a large current from flowing through the failure portion of the diode 16a. When the diode 16a is short-circuited and the voltage value of the capacitor 13a is equal to or less than the voltage value of the positive electrode of the DC output circuit 1, the current does not flow back to the DC output circuit 1, so the reverse blocking IGBT 14b is turned off. Also, the expansion of the failure of the diode 16a can be suppressed. Further, when the voltage value of the capacitor 13b is equal to or less than the voltage value of the positive electrode of the DC output circuit 1, turning the reverse blocking IGBT 14a causes a current to flow from the DC output circuit 1 in the direction of charging only the capacitor 13b. As a result, it is possible to suppress a large current from flowing through the failure portion of the diode 16b. When the diode 16b is short-circuited and the voltage value of the capacitor 13b is equal to or less than the voltage value of the positive electrode of the DC output circuit 1, the current does not flow back to the DC output circuit 1, so the reverse blocking IGBT 14a is turned off. Also, it is possible to suppress the expansion of the failure of the diode 16b.

  The other effects of the chopper circuit 200 according to the second embodiment are the same as those of the chopper circuit 100 according to the first embodiment.

[Third embodiment]
Next, the configuration of the chopper circuit 300 according to the third embodiment will be described with reference to FIGS. Unlike the chopper circuit 100 of the first embodiment, which is a step-up chopper circuit, the chopper circuit 300 of the third embodiment forms a step-down chopper circuit. In addition, about the structure same as the said 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  The configuration of the chopper circuit 300 according to the third embodiment will be described with reference to FIG. FIG. 5 shows an electric circuit diagram of the chopper circuit 300.

  As shown in FIG. 5, the chopper circuit 300 includes a DC output circuit 11. The DC output circuit 11 includes a DC power supply 11a and a DC power supply 11b. The chopper circuit 300 is configured to step down the voltages of the DC power supply 11a and the DC power supply 11b connected in series with each other and apply them to the load 101. That is, the chopper circuit 300 is configured to apply a voltage having a voltage value smaller than the total value of the positive voltage value of the DC power supply 11a and the positive voltage value of the DC power supply 11b to the load 101. The chopper circuit 300 is configured as a so-called three-level step-down chopper circuit. The DC power supply 11a and the DC power supply 11b are examples of the “first DC power supply” and the “second DC power supply” in the claims, respectively.

  The chopper circuit 300 includes a capacitor circuit 23. In the chopper circuit 300, the reactor 2 is connected in series with the capacitor circuit 23. A positive electrode and a negative electrode of the capacitor circuit 23 are connected to both ends of the load 101. In addition, although the capacitor circuit 23 is configured by one capacitor in the third embodiment, it may be configured by a plurality of capacitors.

  The chopper circuit 300 includes a reverse blocking IGBT unit 24. The reverse blocking IGBT unit 24 includes a reverse blocking IGBT 24a and a reverse blocking IGBT 24b. The collector of the reverse blocking IGBT 24a is connected to the positive electrode of the DC power supply 11a. The emitter of the reverse blocking IGBT 24b is connected to the negative electrode of the DC power supply 11b. The reverse blocking IGBT 24a and the reverse blocking IGBT 24b are configured similarly to the reverse blocking IGBT 4a and the reverse blocking IGBT 4b of the first embodiment, respectively. The reverse blocking IGBT 24a and the reverse blocking IGBT 24b are examples of the “first reverse blocking energization control element” and the “second reverse blocking energization control element” in the claims, respectively.

  The chopper circuit 300 includes an antiparallel reverse blocking IGBT unit 25 connected in reverse parallel with the reverse blocking IGBT unit 24. The reverse parallel reverse blocking IGBT unit 25 includes an reverse parallel reverse blocking IGBT 25a connected in reverse parallel to the reverse blocking IGBT 24a. The reverse parallel reverse blocking IGBT unit 25 includes an reverse parallel reverse blocking IGBT 25b connected in reverse parallel with the reverse blocking IGBT 24b. The reverse parallel reverse blocking IGBT 25a and the reverse parallel reverse blocking IGBT 25b are examples of the “third reverse parallel reverse blocking energization control element” and the “fourth reverse parallel reverse blocking energization control element”, respectively.

  The chopper circuit 300 includes a rectifying element unit 26 connected in series with the reverse blocking IGBT unit 24 and the reverse parallel reverse blocking IGBT unit 25. The rectifying element unit 26 includes a bidirectional IGBT module 26a connected in series with the reverse blocking IGBT 24a and the reverse parallel reverse blocking IGBT 25a. The bidirectional IGBT module 26a includes a reverse blocking IGBT 24c and an antiparallel reverse blocking IGBT 25c connected in reverse parallel to the reverse blocking IGBT 24c. The emitter of the reverse blocking IGBT 24a and the emitter of the reverse parallel reverse blocking IGBT 25c are connected. The bidirectional IGBT module 26a is an example of the “first rectifying element” in the claims.

  The rectifying element unit 26 includes a bidirectional IGBT module 26b connected in series with the reverse blocking IGBT 24b and the reverse parallel reverse blocking IGBT 25b. The bidirectional IGBT module 26b includes a reverse blocking IGBT 24d and an antiparallel reverse blocking IGBT 25d connected in reverse parallel to the reverse blocking IGBT 24d. The collector of the reverse blocking IGBT 24b and the collector of the reverse parallel reverse blocking IGBT 25d are connected. The bidirectional IGBT module 26a and the bidirectional IGBT module 26b are connected in series. The bidirectional IGBT module 26b is an example of the “second rectifier element” in the claims.

  Further, the reverse blocking IGBT 24a and the reverse parallel reverse blocking IGBT 25a constitute a bidirectional IGBT module 26c. Further, the reverse blocking IGBT 24b and the reverse parallel reverse blocking IGBT 25b constitute a bidirectional IGBT module 26d.

  The anode of the bidirectional IGBT module 26a is connected to the negative electrode of the DC power supply 11a. The cathode of the bidirectional IGBT module 26b is connected to the positive electrode of the DC power supply 11b. Note that the negative electrode of the DC power supply 11a and the positive electrode of the DC power supply 11b are connected. Specifically, the negative electrode of the DC power supply 11a and the positive electrode of the DC power supply 11b are connected to the collector of the reverse parallel reverse blocking IGBT 25c and the emitter of the reverse parallel reverse blocking IGBT 25d.

  The bidirectional IGBT module 26 a and the bidirectional IGBT module 26 b are connected to both ends of the capacitor circuit 23 via the reactor 2.

  Specifically, the positive electrode of the capacitor circuit 23 and one end of the reactor 2 are connected. The collector of the antiparallel reverse blocking IGBT 25c is connected to the emitter of the reverse parallel reverse blocking IGBT 25d. The emitter of the reverse parallel reverse blocking IGBT 25c and the other end of the reactor 2 are connected, and the collector of the reverse parallel reverse blocking IGBT 25d and the negative electrode of the capacitor circuit 23 are connected.

  The voltage detection unit 7 is connected to the positive electrode of the capacitor circuit 23 and is configured to detect the voltage value Vc of the positive electrode of the capacitor circuit 23.

<Configuration of control unit>
The control unit 19 is connected to the gates of the reverse blocking IGBT 24a, reverse blocking IGBT 24b, reverse blocking IGBT 24c, reverse blocking IGBT 24d, reverse parallel reverse blocking IGBT 25a, reverse parallel reverse blocking IGBT 25b, reverse parallel reverse blocking IGBT 25c, and reverse parallel reverse blocking IGBT 25d. It is configured to control on / off of the eight IGBT elements. The control unit 19 is an example of the “short circuit detection unit” in the claims.

  Here, in the third embodiment, when the short-circuit of the bidirectional IGBT module 26a is detected, the control unit 19 sets the voltage value Vc of the capacitor circuit 23 detected by the voltage detection unit 7 to the positive polarity of the DC power supply 11b. When the voltage value is larger than Va2, the direction in which the current detected by the current detector 8 flows is the direction in which the capacitor circuit 23 is charged (the direction of the arrow C1 in FIG. 5) and the direction in which the capacitor circuit 23 is discharged (in FIG. 5). The reverse parallel reverse blocking IGBT 25b is switched from ON (forward conduction state) to OFF (disconnected state) and the reverse blocking IGBT 24b is switched from OFF (disconnected state) based on the reverse (in the time of inversion) in the direction of arrow C2. It is configured to perform control to turn on (forward conduction state). At this time, the control unit 19 puts the bidirectional IGBT module 26c in the forward off state (the reverse blocking IGBT 24a is off and the reverse parallel reverse blocking IGBT 25a is on).

  Further, when a short circuit of the bidirectional IGBT module 26b is detected and the voltage value Vc of the capacitor circuit 23 detected by the voltage detection unit 7 is larger than the positive voltage value Va1 of the DC power supply 11a, the current detection unit Based on the fact that the direction in which the current detected by 8 is reversed from the direction in which the capacitor circuit 23 is charged (in the direction of arrow C1 in FIG. 5) to the direction in which the capacitor circuit 23 is discharged (in the direction of arrow C2 in FIG. 5) ( At the time of inversion, the reverse parallel reverse blocking IGBT 25a is switched from on (forward conducting state) to off (disconnected state), and the reverse blocking IGBT 24a is switched from off (disconnected state) to on (forward conducting state). It is configured. At this time, the control unit 19 puts the bidirectional IGBT module 26d in the forward direction off state (the reverse blocking IGBT 24b is off and the reverse parallel reverse blocking IGBT 25b is on). The information on the voltage value Va1 and the voltage value Va2 may be stored in the chopper circuit 300 in advance, or may be configured to be obtained by providing a voltage detection unit.

  Further, in the third embodiment, the control unit 19 detects that the short-circuit of the bidirectional IGBT module 26a and the voltage value Vc of the capacitor circuit 23 detected by the voltage detection unit 7 is the positive voltage of the DC power supply 11b. In the case of the value Va2 or less, since the current does not flow backward from the capacitor circuit 23 to the DC power supply 11b, the reverse parallel reverse blocking IGBT 25b is turned on.

  Further, when a short circuit of the bidirectional IGBT module 26b is detected and the voltage value Vc of the capacitor circuit 23 detected by the voltage detection unit 7 is equal to or lower than the voltage value Va1 of the positive electrode of the DC power supply 11a, the capacitor circuit 23 Since the current does not flow backward from the DC power source 11a, the reverse parallel reverse blocking IGBT 25a is turned on.

(Operation of step-down chopper circuit)
<Operation during normal operation>
Next, with reference to FIG. 5, the operation | movement at the time of normal driving | operation of the chopper circuit 300 by 3rd Embodiment is demonstrated. The operation of the chopper circuit 300 is executed by the control process of the control unit 19.

  First, when the reverse blocking IGBT 24a is turned on and the reverse blocking IGBT 24b is turned off, a current flows in the order of the DC power supply 11a, the reverse blocking IGBT 24a, the reactor 2, the capacitor circuit 23, and the reverse parallel reverse blocking IGBT 25d.

  When the reverse blocking IGBT 24a is turned off and the reverse blocking IGBT 24b is turned on, a current flows in the order of the DC power supply 11b, the reverse parallel reverse blocking IGBT 25c, the reactor 2, the capacitor circuit 23, and the reverse blocking IGBT 24b.

  When the reverse blocking IGBT 24a is turned on and the reverse blocking IGBT 24b is turned on, current flows in the order of the DC power supply 11a, the reverse blocking IGBT 24a, the reactor 2, the capacitor circuit 23, the reverse blocking IGBT 24b, and the DC power supply 11b.

  When the reverse blocking IGBT 24a is turned off and the reverse blocking IGBT 24b is turned off, a current flows in the order of the reactor 2, the capacitor circuit 23, the reverse parallel reverse blocking IGBT 25d, and the reverse parallel reverse blocking IGBT 25c.

  In the chopper circuit 300, each period (duty ratio) of the above operation is controlled by the control unit 19, and the above operation is repeated to step down the voltage from the voltage of the DC power source 11a and the DC power source 11b (power). The converted power is supplied to the load 101.

<Operation when short circuit is detected>
Next, with reference to FIG. 5 and FIG. 6, the operation at the time of short circuit detection of the chopper circuit 300 according to the third embodiment will be described. The operation of the chopper circuit 300 is executed by the control process of the control unit 19.

  As shown in FIG. 6, in step S41, it is determined whether or not a short circuit of the bidirectional IGBT module 26a has been detected. When the short circuit of the bidirectional IGBT module 26a is not detected, the process proceeds to step S42, and when the short circuit of the bidirectional IGBT module 26a is detected, the process proceeds to step S43.

  In step S42, it is determined whether or not a short circuit of the bidirectional IGBT module 26b has been detected. When the short circuit of the bidirectional IGBT module 26b is detected, the process proceeds to step S48. When the short circuit of the bidirectional IGBT module 26b is not detected, the operation of the chopper circuit 300 when the short circuit is detected is terminated.

  In addition, it is possible to detect a short circuit during operation during normal operation by repeating steps S41 and S42 during operation during normal operation.

  In step S43, which is performed when the short-circuit of the bidirectional IGBT module 26a is detected in step S41, it is determined whether or not the voltage value Vc of the capacitor circuit 23 is larger than the positive voltage value Va2 of the DC power supply 11b. When the voltage value Vc is larger than the voltage value Va2, the process proceeds to step S44, and when the voltage value Vc is equal to or less than the voltage value Va2, the process proceeds to step S47.

  In step S44, it is determined whether or not the direction of the current flowing through the reactor 2 is the direction in which the capacitor circuit 23 is charged. That is, it is determined whether the direction of the current flowing through the reactor 2 is the direction in which the capacitor circuit 23 is charged (in the direction of arrow C1 in FIG. 5) or the direction in which the capacitor circuit 23 is discharged (in the direction of arrow C2). Then, if the direction of the current flowing through the reactor 2 is a direction for charging the capacitor circuit 23, the process proceeds to step S45. If the direction of the current flowing through the reactor 2 is not a direction for charging the capacitor circuit 23, the process proceeds to step S46.

  In step S45, both the reverse blocking IGBT 24a and the reverse blocking IGBT 24b are turned off. At this time, since a reverse voltage is applied to the reverse parallel reverse blocking IGBT 25a and the reverse parallel reverse blocking IGBT 25b, each is turned on as in the normal operation. As a result, the bidirectional IGBT module 26c and the bidirectional IGBT module 26d are turned off in the forward direction. When the reverse blocking IGBT 24a is turned on, both poles of the DC power source 11a are short-circuited, and a short-circuit current flows through the short-circuited bidirectional IGBT module 26a, which may increase the failure. When the reverse blocking IGBT 24b is turned on, a current flows from the DC power supply 11b in the order of the DC power supply 11b, the short-circuited bidirectional IGBT module 26a, the reactor 2, the capacitor circuit 23, and the reverse blocking IGBT 24b. There is a risk of expanding the failure of 26a. Therefore, when the reverse blocking IGBT 24a and the reverse blocking IGBT 24b are both turned off, the short-circuited bidirectional IGBT module 26a includes the short-circuited bidirectional IGBT module 26a, the reactor 2, the capacitor circuit 23, the reverse circuit for a while. Although the current flows in the direction of charging the capacitor circuit 23 in the order of the parallel reverse blocking IGBT 25d, the current flowing is smaller than when the reverse blocking IGBT 24a and the reverse blocking IGBT 24b are turned on, and the possibility of expanding the failure is reduced.

  In step S45, it is difficult to stop the current flowing through the bidirectional IGBT module 26a by turning off the antiparallel reverse blocking IGBT 25d because the current of the reactor 2 is to be cut off. Therefore, the antiparallel reverse blocking IGBT 25d is kept on while the current of the reactor 2 flows in the direction of charging the capacitor circuit 23.

  Thereafter, the process returns to step S44. That is, steps S44 and S45 are repeated until the direction of the current flowing through the reactor 2 is not in the direction of charging the capacitor circuit 23, and the direction of the current flowing through the reactor 2 is changed from the direction of charging the capacitor circuit 23 to the direction of discharging. When it is reversed, the process proceeds to step S46.

  In step S46, the bidirectional IGBT module 26c is turned off in the forward direction, while the bidirectional IGBT module 26d is turned off in the reverse direction. That is, the reverse blocking IGBT 24b is turned on, and the reverse parallel reverse blocking IGBT 25b is turned off. As a result, the current that tries to reversely flow in the order of the capacitor circuit 23, the reactor 2, the short-circuited bidirectional IGBT module 26a, and the DC power supply 11b does not flow. Thereafter, the operation at the time of short circuit detection of the chopper circuit 300 is ended.

  Further, in step S47, which proceeds when the voltage value Vc is equal to or lower than the voltage value Va2 in step S43, the bidirectional IGBT module 26c and the bidirectional IGBT module 26d are both turned off in the forward direction (the reverse blocking IGBT 24a is turned off and the reverse parallel reverse blocking IGBT 25a is turned on). ON, reverse blocking IGBT 24b is OFF, and reverse parallel reverse blocking IGBT 25b is ON). In this case, since the current does not substantially flow backward, both the bidirectional IGBT module 26c and the bidirectional IGBT module 26d are turned off in the forward direction, whereby the operation of the chopper circuit 300 is stopped. Thereafter, the operation at the time of short circuit detection of the chopper circuit 300 is ended.

  Then, in step S48 that proceeds when the short-circuit of the bidirectional IGBT module 26b is detected in step S42, it is determined whether or not the voltage value Vc of the capacitor circuit 23 is larger than the positive voltage value Va1 of the DC power supply 11a. If the voltage value Vc is greater than the voltage value Va1, the process proceeds to step S49. If the voltage value Vc is equal to or less than the voltage value Va1, the process proceeds to step S52.

  Then, in step S49, it is determined whether or not the direction of the current flowing through the reactor 2 is the direction in which the capacitor circuit 23 is charged. If the direction of the current flowing through the reactor 2 is the direction to charge the capacitor circuit 23, the process proceeds to step S50. If the direction of the current flowing through the reactor 2 is not the direction to charge the capacitor circuit 23, the process proceeds to step S51.

  In step S50, the bidirectional IGBT module 26c and the bidirectional IGBT module 26d are both turned off in the forward direction (the reverse blocking IGBT 24a is turned off, the reverse parallel reverse blocking IGBT 25a is turned on, the reverse blocking IGBT 24b is turned off, and the reverse parallel reverse blocking IGBT 25b is turned on. ). Thereafter, the process returns to step S49.

  In step S51, the bidirectional IGBT module 26c is turned off in the reverse direction (the reverse blocking IGBT 24a is turned on and the reverse parallel reverse blocking IGBT 25a is turned off), and the bidirectional IGBT module 26d is turned off in the forward direction (the reverse blocking IGBT 24b is turned off). Off, and the reverse parallel reverse blocking IGBT 25b is turned on). Thereby, the electric current which tries to reversely flow in the order of the capacitor circuit 23, the reactor 2, the bidirectional IGBT module 26c, the DC power supply 11a, and the short-circuited bidirectional IGBT module 26b does not flow. Thereafter, the operation at the time of short circuit detection of the chopper circuit 300 is ended.

  Further, in step S52, which proceeds when the voltage value Vc is equal to or lower than the voltage value Va1 in step S48, the bidirectional IGBT module 26c and the bidirectional IGBT module 26d are both turned off in the forward direction (the reverse blocking IGBT 24a is turned off and the reverse parallel reverse blocking IGBT 25a is turned on). ON, reverse blocking IGBT 24b is OFF, and reverse parallel reverse blocking IGBT 25b is ON). Thereafter, the operation at the time of short circuit detection of the chopper circuit 300 is ended.

  The other configuration of the chopper circuit 300 according to the third embodiment is the same as that of the chopper circuit 100 according to the first embodiment.

(Effect of the third embodiment)
In the third embodiment, the following effects can be obtained.

  In the third embodiment, as described above, when the short circuit of the bidirectional IGBT module 26a is detected, the control unit 19 turns on the reverse blocking IGBT 24b and turns off the reverse parallel reverse blocking IGBT 25b. When the short circuit 26b is detected, the reverse blocking IGBT 24a is turned on and the reverse parallel reverse blocking IGBT 25a is turned off to cut off the path of the current flowing backward from the capacitor circuit 23 to the DC output circuit 11 side. The circuit 300 is configured. Thereby, when the short circuit of the bidirectional IGBT module 26a is detected, the reverse parallel reverse blocking IGBT 25b is turned off, whereby the reverse current flow from the capacitor circuit 23 to the DC power supply 11b is blocked by the reverse parallel reverse blocking IGBT 25b. The At this time, by turning on the reverse blocking IGBT 24b, the reverse leakage current of the reverse blocking IGBT 24b to which a reverse voltage is applied can be reduced, the reverse breakdown voltage can be improved, and the failure can be suppressed. Further, when a short circuit of the bidirectional IGBT module 26b is detected, the reverse parallel reverse blocking IGBT 25a is turned off, whereby the reverse flow of the current from the capacitor circuit 23 to the DC power supply 11a is blocked by the reverse parallel reverse blocking IGBT 25a. . At this time, by turning on the reverse blocking IGBT 24a, the reverse leakage current of the reverse blocking IGBT 24a to which a reverse voltage is applied can be reduced, the reverse breakdown voltage can be improved, and the failure can be suppressed.

  Further, in the third embodiment, as described above, when the short circuit of the bidirectional IGBT module 26a is detected by the control unit 19, the voltage value of the capacitor circuit 23 detected by the voltage detection unit 7 is the DC power supply 11b. The reverse parallel reverse blocking IGBT 25b is turned on when the voltage value is less than or equal to the positive voltage value. When the short circuit of the bidirectional IGBT module 26b is detected and the voltage value of the capacitor circuit 23 detected by the voltage detection unit 7 is equal to or lower than the voltage value of the positive electrode of the DC power supply 11a, the reverse parallel reverse blocking IGBT 25a is set. The chopper circuit 300 is configured to turn on.

  Thereby, when the short circuit of the bidirectional IGBT module 26a is detected and the voltage value of the capacitor circuit 23 is equal to or less than the voltage value of the positive electrode of the DC power supply 11b, the reverse parallel reverse blocking IGBT 25b to which a reverse voltage is applied is turned on. Thereby, the reverse leakage current of the reverse parallel reverse blocking IGBT 25b can be reduced, the reverse breakdown voltage can be improved, and the failure can be suppressed. If the voltage value of the capacitor circuit 23 is equal to or less than the voltage value of the positive electrode of the DC power supply 11b, the current does not flow backward to the DC power supply 11b. Therefore, even if the reverse parallel reverse blocking IGBT 25b is turned on, the bidirectional IGBT module 26a fails. Can be suppressed. When a short circuit of the bidirectional IGBT module 26b is detected and the voltage value of the capacitor circuit 23 is equal to or lower than the voltage value of the positive electrode of the DC power supply 11a, the reverse parallel reverse blocking IGBT 25a to which a reverse voltage is applied is turned on. Thus, the reverse leakage current of the reverse parallel reverse blocking IGBT 25a can be reduced, the reverse breakdown voltage can be improved, and the failure can be suppressed. If the voltage value of the capacitor circuit 23 is equal to or less than the voltage value of the positive electrode of the DC power supply 11a, the current does not flow backward to the DC power supply 11a. Therefore, even if the reverse parallel reverse blocking IGBT 25a is turned on, the bidirectional IGBT module 26b fails. Can be suppressed.

  In the third embodiment, as described above, when the short circuit of the bidirectional IGBT module 26a is detected, the control unit 19 turns off the reverse blocking IGBT 24b and turns the reverse blocking IGBT 24b off when turning on the reverse parallel reverse blocking IGBT 25b. When turning off the parallel reverse blocking IGBT 25b, the reverse blocking IGBT 24b is turned on. When a short circuit of the bidirectional IGBT module 26b is detected, the reverse blocking IGBT 24a is turned off when the reverse parallel reverse blocking IGBT 25a is turned on, and the reverse blocking IGBT 24a is turned on when the reverse parallel reverse blocking IGBT 25a is turned off. In addition, the chopper circuit 300 is configured. As a result, the current flow is interrupted by turning off one of the reverse blocking IGBT 24a (reverse blocking IGBT 24b) and the reverse parallel reverse blocking IGBT 25a (reverse parallel reverse blocking IGBT 25b), thereby suppressing the expansion of the failure at the short circuit location. In addition, the reverse leakage current can be reduced by turning on the other.

  Other effects of the chopper circuit 300 according to the third embodiment are the same as those of the chopper circuit 100 according to the first embodiment.

[Fourth embodiment]
Next, the configuration of the chopper circuit 400 according to the fourth embodiment will be described with reference to FIGS. In the chopper circuit 400 of the fourth embodiment, the antiparallel reverse blocking IGBT 25a and the antiparallel reverse blocking IGBT 25b are omitted from the configuration of the chopper circuit 300 of the third embodiment. Further, unlike the third embodiment in which the bidirectional IGBT module is provided as a rectifying element, a diode is provided as the rectifying element. In addition, about the structure same as the said 3rd Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  With reference to FIG. 7, the structure of the chopper circuit 400 according to the fourth embodiment will be described. FIG. 7 shows an electric circuit diagram of the chopper circuit 400.

(Configuration of Chopper Circuit According to Fourth Embodiment)
As shown in FIG. 7, the chopper circuit 400 includes a DC output circuit 21. The DC output circuit 21 includes a DC power supply 21a and a DC power supply 21b. The DC power supply 21a and the DC power supply 21b are examples of “third DC power supply” and “fourth DC power supply” in the claims, respectively.

  The chopper circuit 400 includes a reverse blocking IGBT unit 34. The reverse blocking IGBT unit 34 includes a reverse blocking IGBT 34a and a reverse blocking IGBT 34b. The reverse blocking IGBT 34a and the reverse blocking IGBT 34b are configured similarly to the reverse blocking IGBT 24a and the reverse blocking IGBT 24b of the third embodiment, respectively. The reverse blocking IGBT 34a and the reverse blocking IGBT 34b are examples of the “first reverse blocking energization control element” and the “second reverse blocking energization control element” in the claims, respectively.

  As shown in FIG. 7, the chopper circuit 400 includes a rectifying element unit 36 connected in series with the reverse blocking IGBT unit 34. The rectifying element unit 36 includes a diode 36a connected in series with the reverse blocking IGBT 34a. The rectifying element unit 36 includes a diode 36b connected in series with the reverse blocking IGBT 34b. The diode 36a and the diode 36b are examples of the “first rectifier element” and the “second rectifier element” in the claims, respectively.

<Operation when short circuit is detected>
Next, with reference to FIGS. 7 and 8, the operation at the time of short circuit detection of the chopper circuit 400 according to the second embodiment will be described. The operation of the chopper circuit 400 is executed by the control process of the control unit 19a.

  As shown in FIG. 4, it is determined in step S61 whether or not a short circuit of the diode 36a has been detected. When the short circuit of the diode 36a is not detected, the process proceeds to step S62, and when the short circuit of the diode 36a is detected, the process proceeds to step S63.

  In step S62, it is determined whether or not a short circuit of the diode 36b has been detected. When the short circuit of the diode 36b is detected, the process proceeds to step S68. When the short circuit of the diode 36b is not detected, the operation of the chopper circuit 400 when the short circuit is detected is terminated.

  In addition, it is possible to detect a short circuit during the operation during the normal operation by repeating the steps S61 and S62 during the operation during the normal operation.

  Further, in step S63 which proceeds when the short circuit of the diode 36a is detected in step S61, it is determined whether or not the voltage value Vc of the capacitor circuit 23 is larger than the voltage value Va2 of the positive electrode of the DC power supply 21b. When the voltage value Vc is larger than the voltage value Va2, the process proceeds to step S64, and when the voltage value Vc is equal to or less than the voltage value Va2, the process proceeds to step S67.

  Then, in step S64, it is determined whether or not the direction of the current flowing through the reactor 2 is the direction in which the capacitor circuit 23 is charged. Then, if the direction of the current flowing through the reactor 2 is a direction for charging the capacitor circuit 23, the process proceeds to step S65. If the direction of the current flowing through the reactor 2 is not a direction for charging the capacitor circuit 23, the process proceeds to step S66.

  In step S65, both the reverse blocking IGBT 34a and the reverse blocking IGBT 34b are turned off. By turning off the reverse blocking IGBT 34b, charging from the DC power supply 21b to the capacitor circuit 23 is suppressed.

  Thereafter, the process returns to step S64. That is, steps S64 and S65 are repeated until the direction of the current flowing through the reactor 2 is not in the direction of charging the capacitor circuit 23, and the direction of the current flowing through the reactor 2 is changed from the direction of charging the capacitor circuit 23 to the direction of discharging. When it is reversed, the process proceeds to step S66.

  In step S66, the reverse blocking IGBT 34b is turned on. At this time, the reverse breakdown voltage of the reverse blocking IGBT 34b is improved, and the reverse leakage current hardly flows. At this time, the reverse blocking IGBT 34a is turned off. Thereafter, the operation when the short circuit of the chopper circuit 400 is detected is terminated.

  In step S63, which proceeds when the voltage value Vc is equal to or lower than the voltage value Va2, the reverse blocking IGBT 34a and the reverse blocking IGBT 34b are both turned off. In this case, since the current does not substantially flow backward, both the reverse blocking IGBT 34a and the reverse blocking IGBT 34b are turned off, and the operation of the chopper circuit 400 is stopped. Thereafter, the operation when the short circuit of the chopper circuit 400 is detected is terminated.

  Then, in step S68 which proceeds when the short circuit of the diode 36b is detected in step S62, it is determined whether or not the voltage value Vc of the capacitor circuit 23 is larger than the positive voltage value Va1 of the DC power supply 21a. If the voltage value Vc is greater than the voltage value Va1, the process proceeds to step S69. If the voltage value Vc is equal to or less than the voltage value Va1, the process proceeds to step S72.

  Then, in step S69, it is determined whether or not the direction of the current flowing through the reactor 2 is the direction in which the capacitor circuit 23 is charged. If the direction of the current flowing through the reactor 2 is the direction to charge the capacitor circuit 23, the process proceeds to step S70. If the direction of the current flowing through the reactor 2 is not the direction to charge the capacitor circuit 23, the process proceeds to step S71.

  In step S70, both the reverse blocking IGBT 34a and the reverse blocking IGBT 34b are turned off. By turning off the reverse blocking IGBT 34a, charging from the DC power supply 21a to the capacitor circuit 23 is suppressed. Thereafter, the process returns to step S69.

  In step S71, the reverse blocking IGBT 34a is turned on. At this time, the reverse breakdown voltage of the reverse blocking IGBT 34a is improved, and the reverse leakage current hardly flows. At this time, the reverse blocking IGBT 34b is turned off. As a result, the current that tries to reversely flow in the order of the capacitor circuit 23, the reactor 2, the reverse blocking IGBT 34a, the DC power supply 21a, and the shorted diode 36b does not flow. Thereafter, the operation when the short circuit of the chopper circuit 400 is detected is terminated.

  In step S68, which proceeds when the voltage value Vc is equal to or lower than the voltage value Va1, the reverse blocking IGBT 34a and the reverse blocking IGBT 34b are both turned off. Thereafter, the operation when the short circuit of the chopper circuit 400 is detected is terminated.

  The other configuration of the chopper circuit 400 according to the fourth embodiment is the same as that of the chopper circuit 300 according to the third embodiment.

(Effect of 4th Embodiment)
In the fourth embodiment, the following effects can be obtained.

  In the fourth embodiment, as described above, the control unit 19a turns on the reverse blocking IGBT 34b when the short circuit of the diode 36a is detected, and turns on the reverse blocking IGBT 34a when the short circuit of the diode 36b is detected. By doing so, the chopper circuit 400 is configured so as to cut off the path of the current flowing backward from the capacitor circuit 23 to the DC output circuit 21 side. As a result, even when the diode 36a is short-circuited and current flows from the capacitor circuit 23 to the DC power supply 21b and reverse voltage is applied to the reverse blocking IGBT 34b, the reverse blocking current is turned on by turning on the reverse blocking IGBT 34b. Is reduced and the reverse breakdown voltage is increased, so that the current is suppressed from flowing through the short-circuit fault location of the diode 36a. Further, even when the diode 36b is short-circuited and a reverse voltage is applied to the reverse blocking IGBT 34a due to a reverse current flow from the capacitor circuit 23 to the DC power supply 21a, the reverse blocking IGBT 34a is turned on, so the reverse leakage current is reduced and the reverse breakdown voltage is reduced. Becomes higher. Accordingly, it is possible to suppress the expansion of the failure of the diode 36a or the diode 36b.

  Further, in the fourth embodiment, as described above, when the short circuit of the diode 36a is detected by the control unit 19a and the voltage value of the capacitor circuit 23 detected by the voltage detection unit 7 is the positive polarity of the DC power supply 21b. When it is equal to or lower than the voltage value, the reverse blocking IGBT 34b is turned off. When the short circuit of the diode 36b is detected and the voltage value of the capacitor circuit 23 detected by the voltage detection unit 7 is equal to or less than the voltage value of the positive electrode of the DC power supply 21a, the reverse blocking IGBT 34a is turned off. A chopper circuit 400 is configured. Thereby, when the voltage value of the capacitor circuit 23 is equal to or lower than the voltage value of the positive electrode of the DC power supply 21b, turning off the reverse blocking IGBT 34b suppresses charging of the capacitor circuit 23 from the DC power supply 21b. The expansion of the failure of the diode 36a can be suppressed. In addition, when the voltage value of the capacitor circuit 23 is equal to or less than the voltage value of the positive electrode of the DC power supply 21a, turning off the reverse blocking IGBT 34a suppresses charging of the capacitor circuit 23 from the DC power supply 21a. The expansion of the failure of 36b can be suppressed.

  The other effects of the chopper circuit 400 according to the fourth embodiment are the same as those of the chopper circuit 300 according to the third embodiment.

[Modification]
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiment but by the scope of claims for patent, and further includes all modifications (modifications) within the meaning and scope equivalent to the scope of claims for patent.

  For example, in the first to fourth embodiments, the example in which the short circuit of the rectifying element is detected by the current detection unit 8 and the control unit 9 (9a, 19, 19a) has been described, but the present invention is not limited to this. Absent. That is, in the present invention, a dedicated circuit for short circuit detection may be provided separately from the current detection unit 8 and the control unit 9 (9a, 19, 19a).

  Moreover, in the said 1st-4th embodiment, based on the voltage value (Vc1, Vc2, Vc) of the capacitor circuit 3 (13, 23) detected by the voltage detection part 7 when a short circuit is detected, Although the example which controls ON / OFF of a reverse blocking IGBT element (antiparallel reverse blocking IGBT element) has been shown, the present invention is not limited to this. For example, when a short circuit is detected, on / off of the reverse blocking IGBT element (reverse parallel reverse blocking IGBT element) may be controlled without referring to the voltage value detected by the voltage detection unit 7. . For example, in the first embodiment, it may be configured to perform the control to turn off the reverse parallel reverse blocking IGBT 6b based only on the detection of the short circuit of the bidirectional IGBT module 6a.

  Moreover, in the said 1st-4th embodiment, when a short circuit is detected, based on both the detected value of the voltage detection part 7, and the detection result of the electric current detection part 8, a reverse blocking IGBT element (reverse parallel reverse blocking) Although an example of controlling on / off of the IGBT element has been shown, the present invention is not limited to this. For example, on / off control of the reverse blocking IGBT element (reverse parallel reverse blocking IGBT element) may be performed based on one of the detection value of the voltage detection unit 7 or the detection result of the current detection unit 8.

  Moreover, in the said 1st-4th embodiment, the example which controls ON / OFF of a reverse blocking IGBT element (antiparallel reverse blocking IGBT element) was shown at the time of the direction where the electric current direction which the electric current detection part 8 detects reverses. However, the present invention is not limited to this. For example, on-off control of the reverse blocking IGBT element (reverse parallel reverse blocking IGBT element) may be controlled based on the inversion. That is, the time of inversion and the time of on / off control need not be completely coincident, and may be before the current is reversed from the direction in which the capacitor 3a is charged. For example, in the first embodiment, if the reverse withstand voltage and reverse leakage current of the reverse parallel reverse blocking IGBT 5b are not a problem, the direction of the current is determined based on the fact that the short circuit of the bidirectional IGBT module 6a is detected. Even when the battery is flowing in the direction of charging, the reverse parallel reverse blocking IGBT 5b may be controlled to be turned off. Further, the direction of the current may be delayed from the time when the direction of the current is reversed from the direction of charging the capacitor 3a. Note that the time point when the direction of the current is reversed from the direction of charging the capacitor 3a can be predicted based on the detection value of the current detection unit 8 or the time point when the short-circuit of the bidirectional IGBT module 6a is detected.

  In the first to fourth embodiments, the reverse blocking IGBT 4a (14a, 24a, 34a), the reverse blocking IGBT 4b (14b, 24b, 34b), the reverse parallel reverse blocking IGBT 5a (25a), and the reverse parallel reverse blocking IGBT 5b (25b) ), The bidirectional IGBT module (6a, 6b, 26a, 26b), and the diode (16a, 16b, 36a, 36b) may be made of either silicon or a wide band gap semiconductor.

  In the first to fourth embodiments, the reverse blocking IGBT 4a (14a, 24a, 34a), the reverse blocking IGBT 4b (14b, 24b, 34b), the reverse parallel reverse blocking IGBT 5a (25a), and the reverse parallel reverse blocking IGBT 5b (25b) ) And a reverse blocking MOSFET having a reverse breakdown voltage due to a Schottky barrier of the drain electrode may be used instead of the bidirectional IGBT module (6a, 6b, 26a, 26b).

  In the first to fourth embodiments, for convenience of explanation, the control processing of the present invention has been described using a flow-driven flowchart in which processing is performed in order along the processing flow. Not limited. In the present invention, the control processing operation may be performed by event-driven (event-driven) processing that executes processing for each event. In this case, it may be performed by a complete event drive type or a combination of event drive and flow drive.

1, 11, 21 DC output circuit 2 Reactor 3, 13, 23 Capacitor circuit 3a Capacitor (first capacitor)
3b capacitor (second capacitor)
4a, 14a, 24a, 34a Reverse blocking IGBT (first reverse blocking energization control element)
4b, 14b, 24b, 34b Reverse blocking IGBT (second reverse blocking energization control element)
5a Reverse parallel reverse blocking IGBT (first reverse parallel reverse blocking conduction control element)
5b Reverse parallel reverse blocking IGBT (second reverse parallel reverse blocking conduction control element)
6a, 26a Bidirectional IGBT module (first rectifier)
6b, 26b Bidirectional IGBT module (second rectifier)
7 Voltage detector 8 Current detector (short-circuit detector)
9, 9a, 19, 19a Control unit (short-circuit detection unit)
11a DC power supply (first DC power supply)
11b DC power supply (second DC power supply)
13a capacitor (third capacitor)
13b Capacitor (4th capacitor)
16a, 36a Diode (first rectifier)
16b, 36b Diode (second rectifier)
21a DC power supply (third DC power supply)
21b DC power supply (4th DC power supply)
25a Reverse parallel reverse blocking IGBT (third reverse parallel reverse blocking conduction control element)
25b Reverse parallel reverse blocking IGBT (fourth reverse parallel reverse blocking conduction control element)
100, 200, 300, 400 Chopper circuit 101 Load

Claims (14)

Reactor,
DC output circuit,
A capacitor circuit connected in parallel to the load;
A first reverse blocking energization control element connected to the positive electrode of the capacitor circuit and connected to the positive electrode of the DC output circuit;
A first rectifying element connected in series with the first reverse blocking conduction control element;
A second reverse blocking energization control element connected to the negative electrode of the capacitor circuit and connected to the negative electrode of the DC output circuit;
A second rectifying element connected in series with the second reverse blocking conduction control element;
A short-circuit detector for detecting a short circuit between the first rectifier element and the second rectifier element;
When a short circuit of the first rectifying element is detected by the short circuit detecting unit, on / off of the second reverse blocking energization control element is controlled, and when a short circuit of the second rectifying element is detected by the short circuit detecting unit And a control unit that cuts off a path of a current flowing backward from the capacitor circuit to the DC output circuit side by controlling on / off of the first reverse blocking energization control element. A voltage detection unit for detecting a voltage value of the capacitor circuit;
The controller is configured such that the voltage value of the capacitor circuit detected by the voltage detector when the short circuit of the first rectifying element is detected by the short circuit detector is greater than the voltage value of the positive electrode of the DC output circuit. When it is larger, the second reverse blocking energization control element is controlled to be turned on / off, and the voltage of the capacitor circuit detected by the voltage detection unit when the short circuit detection unit detects a short circuit of the second rectification element. 2. The chopper circuit according to claim 1, wherein the chopper circuit is configured to control on / off of the first reverse blocking conduction control element when a value is larger than a voltage value of a positive electrode of the DC output circuit. The short circuit detection unit includes a current detection unit that detects a value and direction of a current between the capacitor circuit and the DC output circuit,
The controller is configured such that the voltage value of the capacitor circuit detected by the voltage detector when the short-circuit of the first rectifier element is detected by the current detector is higher than the voltage value of the positive electrode of the DC output circuit. On the other hand, on the basis of the fact that the direction of the current detected by the current detection unit is reversed, the second reverse-blocking energization control element is controlled to be turned on / off. When detected, and when the voltage value of the capacitor circuit detected by the voltage detection unit is larger than the voltage value of the positive electrode of the DC output circuit, the direction of the current detected by the current detection unit is reversed. The chopper circuit according to claim 2, wherein the chopper circuit is configured to control on / off of the first reverse blocking conduction control element based on the above.   The controller is configured such that the voltage value of the capacitor circuit detected by the voltage detector when the short-circuit of the first rectifier element is detected by the current detector is higher than the voltage value of the positive electrode of the DC output circuit. On the other hand, the second reverse-blocking energization control element is turned on and off based on the fact that the direction of the current detected by the current detector is reversed from the direction of charging the capacitor circuit to the direction of discharging the capacitor circuit when the current is larger. And the voltage value of the capacitor circuit detected by the voltage detection unit is greater than the voltage value of the positive electrode of the DC output circuit when the current detection unit detects a short circuit of the second rectifier element. In this case, the direction of the current detected by the current detector is reversed from the direction of charging the capacitor circuit to the direction of discharging the capacitor circuit. Based on the first and is configured to control on and off of reverse blocking conduction control element, the chopper circuit according to claim 3. The chopper circuit is a step-up chopper circuit;
A first reverse parallel reverse blocking energization control element connected in antiparallel to the first reverse blocking energization control element;
A second reverse parallel reverse blocking energization control element connected in reverse parallel to the second reverse blocking energization control element;
The reactor is connected in series with the DC output circuit,
The first reverse blocking energization control element and the second reverse blocking energization control element are connected to both ends of the DC output circuit via the reactor,
The capacitor circuit has a positive electrode connected to a cathode of the first rectifying element and a negative electrode connected to a connection point between the first reverse blocking conduction control element and the second reverse blocking conduction control element. A first capacitor and a positive electrode are connected to the connection point of the first reverse blocking energization control element and the second reverse blocking energization control element, and a negative electrode is connected to the anode of the second rectifying element. 2 capacitors,
The control unit turns on the second reverse blocking energization control element and turns off the second reverse parallel reverse blocking energization control element when the short circuit detecting unit detects a short circuit of the first rectifying element, When the short circuit of the second rectifying element is detected by the short circuit detecting unit, the capacitor circuit is turned on by turning on the first reverse blocking conduction control element and turning off the first reverse parallel blocking prevention control element. The chopper circuit according to any one of claims 1 to 4, wherein the chopper circuit is configured to block a path of a current that flows backward to the DC output circuit side. A voltage detection unit for detecting a voltage value of the capacitor circuit;
The control unit is configured such that the voltage value of the first capacitor detected by the voltage detection unit is equal to or less than the voltage value of the positive electrode of the DC output circuit when the short circuit detection unit detects a short circuit of the first rectifier element. In this case, when the second reverse parallel reverse blocking energization control element is turned on and a short circuit of the second rectifying element is detected by the short circuit detector, and the second capacitor detected by the voltage detector 6. The chopper circuit according to claim 5, wherein the chopper circuit is configured to turn on the first reverse-parallel reverse-blocking energization control element when a voltage value is equal to or less than a voltage value of a positive electrode of the DC output circuit.   The control unit turns off the second reverse blocking energization control element when turning on the second reverse parallel reverse blocking energization control element when the short circuit detecting unit detects a short circuit of the first rectifying element. When the second reverse parallel reverse blocking energization control element is turned off, the second reverse blocking energization control element is turned on. When the short circuit detecting unit detects a short circuit of the second rectifying element, the first reverse When turning on the parallel reverse blocking energization control element, the first reverse blocking energization control element is turned off. When turning off the first reverse parallel reverse blocking energization control element, the first reverse blocking energization control element is turned on. The chopper circuit according to claim 5 or 6 constituted as follows. The chopper circuit is a step-up chopper circuit;
The reactor is connected in series with the DC output circuit,
The first reverse blocking energization control element and the second reverse blocking energization control element are connected to both ends of the DC output circuit via the reactor,
The capacitor circuit has a positive electrode connected to a cathode of the first rectifying element and a negative electrode connected to a connection point between the first reverse blocking conduction control element and the second reverse blocking conduction control element. A third capacitor and a positive electrode are connected to the connection point between the first reverse blocking conduction control element and the second reverse blocking conduction control element, and a negative electrode is connected to the anode of the second rectifying element. 4 capacitors,
The control unit turns on the second reverse blocking energization control element when the short circuit detecting unit detects a short circuit of the first rectifying element, and the short circuit detecting unit detects a short circuit of the second rectifying element. When configured, the first reverse-blocking energization control element is turned on to cut off a current path that flows backward from the capacitor circuit to the DC output circuit. The chopper circuit according to any one of claims. A voltage detection unit for detecting a voltage value of the capacitor circuit;
The control unit is configured such that the voltage value of the third capacitor detected by the voltage detection unit is equal to or less than the voltage value of the positive electrode of the DC output circuit when the short-circuit detection unit detects a short circuit of the first rectifier element. In this case, the voltage value of the fourth capacitor detected by the voltage detection unit when the second reverse blocking energization control element is turned off and a short circuit of the second rectifying element is detected by the short circuit detection unit. The chopper circuit according to claim 8, wherein the first reverse-blocking energization control element is turned off when is less than or equal to a voltage value of a positive electrode of the DC output circuit. The chopper circuit is a step-down chopper circuit;
A third reverse parallel reverse blocking energization control element connected in antiparallel to the first reverse blocking energization control element;
A fourth reverse parallel reverse blocking energization control element connected in reverse parallel to the second reverse blocking energization control element;
The reactor is connected in series with the capacitor circuit,
The first rectifying element and the second rectifying element are connected to both ends of the capacitor circuit via the reactor,
The DC output circuit includes a first DC power source having a positive electrode connected to the first reverse blocking energization control element, a negative electrode connected to an anode of the first rectifying element, and a positive electrode connected to the first DC power source. And a second DC power source connected to the cathode of the second rectifying element and the negative electrode connected to the second reverse blocking conduction control element,
The control unit turns on the second reverse blocking energization control element and turns off the fourth reverse parallel reverse blocking energization control element when the short circuit detecting unit detects a short circuit of the first rectifying element, By turning on the first reverse blocking energization control element and turning off the third reverse parallel reverse blocking energization control element when the short circuit detection unit detects a short circuit of the second rectifying element, the capacitor circuit The chopper circuit according to any one of claims 1 to 4, wherein the chopper circuit is configured to block a path of a current that flows backward to the DC output circuit side. A voltage detection unit for detecting a voltage value of the capacitor circuit;
The control unit is configured such that the voltage value of the capacitor circuit detected by the voltage detection unit is equal to or lower than the voltage value of the positive electrode of the second DC power source when the short circuit detection unit detects a short circuit of the first rectifying element. In this case, when the fourth reverse parallel reverse blocking energization control element is turned on, and the short circuit detecting unit detects a short circuit of the second rectifying element and the voltage of the capacitor circuit detected by the voltage detecting unit 11. The chopper circuit according to claim 10, wherein the chopper circuit is configured to turn on the third reverse parallel reverse blocking energization control element when a value is equal to or less than a voltage value of a positive electrode of the first DC power supply.   The control unit turns off the second reverse blocking energization control element when turning on the fourth reverse parallel reverse blocking energization control element when the short circuit detecting unit detects a short circuit of the first rectifying element. When turning off the fourth reverse parallel reverse blocking energization control element, turning on the second reverse blocking energization control element, and when the short circuit detecting unit detects a short circuit of the second rectifying element, When turning on the parallel reverse blocking energization control element, the first reverse blocking energization control element is turned off. When turning off the third reverse parallel reverse blocking energization control element, the first reverse blocking energization control element is turned on. The chopper circuit according to claim 10 or 11, configured as described above. The chopper circuit is a step-down chopper circuit;
The reactor is connected in series with the capacitor circuit,
The first rectifying element and the second rectifying element are connected to both ends of the capacitor circuit via the reactor,
The DC output circuit includes a third DC power source having a positive electrode connected to the first reverse blocking energization control element, a negative electrode connected to an anode of the first rectifying element, and a positive electrode connected to the third DC power source. And a fourth direct current power source connected to the cathode of the second rectifying element and the negative electrode connected to the second reverse blocking conduction control element,
The control unit turns on the second reverse blocking energization control element when the short circuit detecting unit detects a short circuit of the first rectifying element, and the short circuit detecting unit detects a short circuit of the second rectifying element. When configured, the first reverse-blocking energization control element is turned on to cut off a current path that flows backward from the capacitor circuit to the DC output circuit. The chopper circuit according to any one of claims. A voltage detection unit for detecting a voltage value of the capacitor circuit;
The control unit is configured such that the voltage value of the capacitor circuit detected by the voltage detection unit is equal to or less than the voltage value of the positive electrode of the fourth DC power source when the short circuit detection unit detects a short circuit of the first rectifying element. In this case, the second reverse-blocking energization control element is turned off, and the short-circuit detecting unit detects a short circuit of the second rectifying element and the voltage value of the capacitor circuit detected by the voltage detecting unit is 14. The chopper circuit according to claim 13, wherein the chopper circuit is configured to turn off the first reverse blocking conduction control element when the voltage value is equal to or lower than a voltage value of a positive electrode of the third DC power supply.

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