JP4862405B2 - Insulated gate type power semiconductor device failure detection device - Google Patents

Description

  The present invention relates to a failure detection apparatus for an insulated gate power semiconductor device that detects a short circuit failure or a disconnection failure of the insulated gate power semiconductor device.

  Generally, in a power converter, when a capacity is insufficient with only one semiconductor element, a predetermined capacity is obtained by connecting a plurality of semiconductor elements in parallel or in series. Moreover, the power converter which combined the parallel connection and the series connection is also employ | adopted.

  In such a power converter composed of a plurality of semiconductor elements, a failure of one semiconductor element may adversely affect a healthy semiconductor element. Therefore, it is required that the failure of the semiconductor element can be detected promptly. Has been. When any of the plurality of semiconductor elements fails, the operation of the power converter is stopped in order to ensure safety.

  An insulated gate power semiconductor element such as an IGBT (Insulated Gate Bipolar Transistor) is used as a semiconductor element constituting the power converter. There are a short circuit failure and a disconnection failure in the failure of the insulated gate power semiconductor element. First, as for a short-circuit fault of an insulated gate power semiconductor element, a method of detecting a fault by using a collector-emitter voltage when OFF is widely known. When a short circuit failure occurs in the insulated gate type power semiconductor element, the collector-emitter voltage at the time of OFF becomes almost 0 V, so that it can be detected that the short circuit has occurred. In addition, there is one that detects a short-circuit failure in the insulated gate power semiconductor element by determining the short-circuit failure based on the magnitude of the peak value of the gate current, so that the failure of the insulated gate power semiconductor element can be detected quickly. (For example, refer to Patent Document 1).

On the other hand, with regard to the disconnection failure of the insulated gate type power semiconductor element, if the semiconductor elements are not connected in parallel, the power converter will be disconnected, so there is no need to detect the disconnection failure of each semiconductor element. . In addition, when semiconductor elements are connected in parallel, the power converter can be operated by continuing operation until it is detected due to a control abnormality, etc., or by detecting a current between the collector and emitter by connecting a small resistance in series. Had stopped.
JP 2002-281736 A

  However, since the operation of the power converter is stopped due to the failure of one semiconductor element constituting the power converter composed of a plurality of semiconductor elements, the operating rate of the power converter is lowered.

  Therefore, it is conceivable that a semiconductor element having a large capacity is used in advance, and even if one semiconductor element fails, it is possible to secure the capacity with the remaining healthy semiconductor elements to avoid stopping the power converter. The utilization factor of the element deteriorates.

  For example, in the case of a power converter configured by connecting three semiconductor elements in parallel and connecting the three parallel element groups in series in three stages, if a disconnection failure occurs in any of the semiconductor elements Then, two semiconductor elements connected in parallel to the broken semiconductor element bear a current of three. On the other hand, when a short circuit failure occurs in any of the semiconductor elements, the remaining two stages of semiconductor elements connected in series with the short circuit semiconductor element bear the voltage for three stages.

  In the case of a short circuit failure of a semiconductor element, it may not be possible to avoid stopping the power converter even if a semiconductor element having a large capacity is used in advance. That is, when the semiconductor elements are connected in parallel, the gate drive circuit may be shared in order to synchronize the timing of the on / off signals of the respective semiconductor elements. In this case, the semiconductor in which the short-circuit fault has occurred due to the occurrence of a short-circuit fault. Even in the case of a healthy semiconductor element of a parallel element group including elements, the collector-emitter voltage does not increase when turned off, and becomes approximately 0V. When the collector-emitter voltage of the semiconductor element at the time of off is almost 0 V, the gate power supply self-sufficiency system (a system that can supply power required for the gate drive circuit from the main circuit itself without receiving power from another power source) The gate voltage cannot be secured. Therefore, since the healthy element is turned off, the current is concentrated on the semiconductor element in which the short circuit failure has occurred, and the semiconductor element in which the short circuit failure has occurred may cause thermal destruction. In addition, when a semiconductor element in which a short-circuit fault has occurred has a short-circuit fault with a certain degree of resistance, the gate voltage of the sound semiconductor element fluctuates due to the influence of the semiconductor element in which the short-circuit fault has occurred. The element is repeatedly turned on and off incompletely. In this case, even if a semiconductor element having a large capacity is used in advance, there is a possibility of further element failure.

  On the other hand, regarding the failure detection of a semiconductor element, when a short circuit failure occurs in any of a plurality of insulated gate power semiconductor elements connected in parallel, the insulated gate power semiconductor element in which the short circuit failure has occurred is turned off. Since the collector-emitter voltage of the semiconductor device is almost 0 V, it can be seen that a short circuit failure has occurred in any of the insulated gate type power semiconductor elements. It cannot be detected.

  Moreover, in the thing of patent document 1, since the short circuit fault is determined by the magnitude | size of the peak value of gate current, the fault current which does not produce a big peak value cannot be detected. For example, a failure cannot be detected when the duration of the device is long and the amount of increase in current is small compared to a semiconductor device in which the on-gate current of the device in which the short circuit failure has occurred is healthy.

  Furthermore, the thing of patent document 1 does not have a function which detects the disconnection failure of an insulated gate type power semiconductor element. In general, a disconnection failure of an insulated gate power semiconductor device stops the converter because the main current is cut off when the semiconductor devices are not connected in parallel. On the other hand, when the semiconductor elements are connected in parallel, no current flows through the semiconductor element in which the disconnection failure occurs even though the ON signal is output from the gate, and the corresponding current flows to other healthy elements. As a result, a healthy semiconductor device may also fail. For this reason, it was necessary to detect disconnection instantaneously and stop the power converter. However, without providing a disconnection failure detection circuit, the power converter is stopped by operating until a healthy semiconductor element is abnormal or by detecting a disconnection failure by a current between the collector and the emitter.

  An object of the present invention is to provide a failure detection device for an insulated gate power semiconductor element capable of accurately detecting a short circuit failure or a disconnection failure of the insulated gate power semiconductor element.

According to a first aspect of the present invention, there is provided a failure detection apparatus for an insulated gate power semiconductor element, wherein the failure detection apparatus for an insulated gate power semiconductor element detects a disconnection failure of the insulated gate power semiconductor element. An off-gate current flowing from the gate of the element to the gate drive circuit is compared with a current in a healthy state, and a disconnection fault detecting unit for detecting a disconnection fault is provided.

According to a second aspect of the present invention, there is provided a failure detection apparatus for an insulated gate type power semiconductor device, wherein the insulation gate type power semiconductor device detects a short circuit failure and a disconnection failure of the insulated gate type power semiconductor device. A short-circuit fault detection unit for detecting a short-circuit fault by comparing an on-gate current flowing from the gate drive circuit of the power semiconductor element into the gate or an off-gate current flowing from the gate of the insulated gate power semiconductor element into the gate drive circuit with a current in a healthy state; And a disconnection fault detecting unit for detecting a disconnection fault by comparing at least an off-gate current flowing from the gate of the insulated gate power semiconductor element into the gate drive circuit with a current in a healthy state.

According to a third aspect of the present invention, there is provided the failure detection device for an insulated gate type power semiconductor device according to the first or second aspect , wherein the disconnection failure detection unit is configured to operate the insulated gate when the off-gate current is smaller than a healthy current. Detecting a disconnection failure of a power semiconductor element.

According to a fourth aspect of the present invention, there is provided the failure detection device for an insulated gate power semiconductor element according to the first or second aspect , wherein the disconnection fault detection unit is a current when the on-gate current of the insulated gate power semiconductor element is healthy. When the off-gate current is smaller than the current at the time of sound, it is detected as a disconnection failure on the collector side of the insulated gate power semiconductor element, and the on-gate current and off-gate current of the insulated gate power semiconductor element are When the current is smaller than the current, it is detected as a disconnection failure on the emitter side of the insulated gate power semiconductor element.

According to a fifth aspect of the present invention, there is provided the failure detection apparatus for an insulated gate power semiconductor device according to any one of the first to fourth aspects, wherein the short-circuit fault detection unit or the disconnection fault detection unit is an on-gate current or an off-gate current. Is integrated, and a short circuit failure or a disconnection failure is detected by comparing the integrated value with a predetermined value.

According to a sixth aspect of the present invention, there is provided a failure detection apparatus for an insulated gate type power semiconductor device according to the fifth aspect , wherein the predetermined value is an on-gate current or an off gate of a plurality of healthy insulated gate type power semiconductor devices. It is an average value of current or a data value of past on-gate current or off-gate current of the self-insulated gate type power semiconductor element.

  According to the present invention, the on-gate current or off-gate current of the insulated gate type power semiconductor device is compared with the current at the time of health to detect a short circuit failure or disconnection failure of the insulated gate type power semiconductor device. It is possible to accurately detect a short circuit failure or a disconnection failure of a power semiconductor element.

  FIG. 1 is a configuration diagram of a power conversion unit according to an embodiment of the present invention. The power conversion unit of the present embodiment is configured by serially connecting multiple parallel element groups formed by connecting a plurality of semiconductor elements in parallel. FIG. 1 shows a power conversion unit in which parallel element groups in which three semiconductor elements are connected in parallel are connected in series in three stages.

  For example, three semiconductor elements 12a1, 12a2, and 12a3 are connected in parallel to the first-stage parallel element group 11a, and three semiconductor elements 12b1, 12b2, and 12b3 are connected in parallel to the second-stage parallel element group 11b. In addition, three semiconductor elements 12c1, 12c2, and 12c3 are connected in parallel to the third-stage parallel element group 11c. The first-stage parallel element group 11a, the second-stage parallel element group 11b, and the third-stage parallel-element group 11c The parallel element group 11c is connected in series in three stages to constitute a power conversion unit. The power converter is configured by combining a plurality of power converters.

  Each parallel element group 11a, 11b, and 11c is provided with gate drive circuits 13a, 13b, and 13c, respectively. The gate drive circuit 13 outputs a gate signal to the gate of each semiconductor element 12 constituting the power conversion unit, and is provided in common for the semiconductor elements 12 connected in parallel in the parallel element group 11. Yes. For example, the gate drive circuit 13a is provided in common for the three semiconductor elements 12a1, 12a2, and 12a3 connected in parallel in the first-stage parallel element group 11a, and the gates of the three semiconductor elements 12a1, 12a2, and 12a3. The gate signal is output at almost the same timing. The same applies to the gate drive circuits 13b and 13c. Here, the reason why the gate drive circuit 13 is provided in common to the parallel-connected semiconductor elements 12 of the parallel element group 11 is to enable the on-off timing of the parallel-connected semiconductor elements 12 to be performed almost simultaneously. It is also possible to provide a drive circuit for each of the semiconductor elements 12 constituting the parallel element group 11 and control the on / off timing of the semiconductor elements 12 connected in parallel to be substantially the same.

  Gate signals from the first-stage gate drive circuit 13a are respectively input to the gate input resistors Ra1, Ra2, and Ra3 connected in parallel, and the first-stage parallel element group 11a is connected via the switches Sa1, Sa2, and Sa3. A gate signal is output to the three semiconductor elements 12a1, 12a2, and 12a3 connected in parallel. Similarly, the gate signals of the second stage gate drive circuit 13b and the third gate drive circuit 13c are respectively input to the gate input resistors Rb1, Rb2, and Rb3 (Rc1, Rc2, and Rc3) connected in parallel, and the switch Sb1. , Sb2, Sb3 (Sc1, Sc2, Sc3), three semiconductor elements 12b1, 12b2, 12b3 (12c1) connected in parallel in the second-stage parallel element group 11b (third-stage parallel element group 11c) , 12c2, 12c3).

The failure detection device 14 is for individually detecting failures of the individual semiconductor elements 12 constituting the power conversion unit. That is, three semiconductor elements 12a1, 12a2, 12a3 connected in parallel in the first-stage parallel element group 11a, and three semiconductor elements 12b1, 12b2, 12b3 connected in parallel in the second-stage parallel element group 11b, Based on the gate currents Iga1 to Igc3 of the three semiconductor elements 12c1, 12c2, and 12c3 connected in parallel in the third-stage parallel element group 11c, a failure of each semiconductor element 12 is individually detected. For example, when a failure of one of the semiconductor elements 12 is detected so that the switch Sa1 of the failed semiconductor element 12a1 is turned off when a failure of the semiconductor element 12a1 is detected, the switch of the failed semiconductor element 12 is switched Turn off S. As the switch S, a small capacity MOSFET or the like can be used.

  As a result, the supply of the gate current to the semiconductor element in which the short-circuit failure has occurred is interrupted, so that it is possible to prevent the gate power supply voltage from being lowered when the gate signal is generated to the healthy semiconductor element. Accordingly, it is possible to supply a gate current to a healthy semiconductor element, and it is possible to continue the operation of the power converter even when a short circuit failure occurs in the semiconductor element.

  Furthermore, if the ON signal is continuously output to the gate of the healthy semiconductor element connected in parallel with the semiconductor element in which the short-circuit fault has occurred, the sound semiconductor element will not be turned off, and the semiconductor element in which the short-circuit fault has occurred can be prevented. Overvoltage and overcurrent due to influence can be prevented.

  In addition, since the gate current supply is cut off even for the semiconductor element in which the disconnection failure has occurred, the sneak current from the gate to the gate drive circuit can be prevented, and the abnormal voltage or abnormality generated in the semiconductor element in which the disconnection failure has occurred. Generation of current can be prevented. Accordingly, it is possible to supply a gate current to a healthy semiconductor element, and it is possible to continue operation of the power converter even when a disconnection failure occurs in the semiconductor element.

  Next, failure detection of the semiconductor element 12 by the failure detection device 14 will be described. FIG. 2 is a block configuration diagram of the failure detection apparatus for the semiconductor element 12. However, for the sake of explanation, the failure detection of one semiconductor element is shown. The semiconductor element 12 has a collector C, an emitter E, and a gate G. The gate drive circuit 13 applies a gate voltage Vge between the gate G and the emitter E to perform on / off control. The gate G is provided with a gate input resistance Rg, and the gate current Ig flowing through the gate input resistance Rg is detected by the current detection unit 15 of the failure detection device 14. The current detector 15 detects the gate current Ig based on the voltage across the gate input resistor Rg. In this embodiment, the gate current is detected from the voltage across the gate input resistor. For example, a gate current detection resistor is provided separately from the gate input resistor and the gate current is detected from the voltage across the gate input resistor. A method may be used.

  The gate current Ig detected by the current detection unit 15 of the failure detection device 14 is input to the disconnection failure detection unit 16 and the short circuit failure detection unit 17. The short-circuit fault detection unit 17 detects a short-circuit fault by comparing the on-gate current flowing from the gate drive circuit 13 to the gate G or the off-gate current flowing from the gate G to the gate drive circuit 13 with the current in the healthy state. Further, the disconnection failure detection unit 16 detects a disconnection failure by comparing at least an off-gate current flowing from the gate G into the gate drive circuit 13 with a current in a healthy state.

  FIG. 3 is an explanatory diagram of on-gate current and off-gate current when the semiconductor element is an insulated gate power semiconductor element such as an IGBT (Insulated Gate Bipolar Transistor). Assuming that a gate voltage Vge is applied between the gate G and the emitter E of the semiconductor element at time t1, an on-gate current Ig1 flows. The on-gate current Ig1 becomes a relatively large on-gate current Ig11 in the steep rising period T1 of the gate voltage Vge from the time point t1 to the time point t2, and is relatively small in the slow rising period T2 of the gate voltage Vge from the time point t2 to the time point t3. Value of the on-gate current Ig12. That is, the on-gate current Ig11 flows due to the application of the gate voltage Vge at time t1, and the semiconductor element starts to turn on and is turned on at time t3.

  If the gate voltage Vge is reduced at time t4, an off-gate current Ig2 flows. The off-gate current Ig2 becomes a relatively large off-gate current Ig21 in the period T5 from the time point t4 to the time point t5 due to the fall of the gate voltage Vge, and the off-gate current Ig2 is relatively large in the sharp fall period T4 of the gate voltage Vge from the time point t5 to the time point t6. The off-gate current Ig22 has a small value. That is, the off-gate current Ig21 flows due to the decrease in the gate voltage Vge at time t4, the semiconductor element starts to turn off, and is turned off at time t6.

  4 is an explanatory diagram of the on-gate current and off-gate current when the semiconductor element is healthy, FIG. 4A is an explanatory diagram of the on-gate currents Ig11 and Ig12, and FIG. 4B is an explanatory diagram of the off-gate currents Ig21 and Ig22. is there. When the semiconductor element is healthy, when the gate voltage Vge is applied, the on-gate currents Ig11 and Ig12 having the characteristics shown in FIG. 3 having a magnitude within a predetermined range flow, and when the gate voltage Vge is lowered, the magnitude is within a predetermined range. The off-gate currents Ig21 and Ig22 having the characteristics shown in FIG.

  The on-gate current Ig1 and off-gate current Ig2 when the semiconductor element is healthy are stored in advance in the failure detection device 14 as predetermined values. For example, the predetermined value is obtained by integrating the absolute values of the on-gate current Ig1 and the off-gate current Ig2, and setting the integrated values as the values of the on-gate current Ig1 and the off-gate current Ig2. In this case, it is also possible to employ the average value of the on-gate current or off-gate current of a plurality of healthy semiconductor elements. It is also possible to use the data value of the past on-gate current or off-gate current of the self semiconductor element that is the target of failure detection. Furthermore, it is possible to expect a safety factor for the predetermined value.

  Then, the failure detection device 14 integrates the absolute value of the on-gate current Ig1 or off-gate current Ig2, and detects a short-circuit failure or a disconnection failure by comparing the integrated value with a predetermined value.

  Next, a short-circuit fault detection method in the short-circuit fault detection unit 17 will be described. FIG. 5 is an explanatory diagram of on-gate current and off-gate current when the insulated gate type power semiconductor device is in a short circuit failure state, FIG. 5 (a) is an explanatory diagram of on-gate currents Ig11 and Ig12, and FIG. 5 (b) is an off-gate current. It is explanatory drawing of electric current Ig21 and Ig22.

  Since the short-circuit failure of the insulated gate type power semiconductor element is a state where the collector C and the emitter E are short-circuited, the on-gate currents Ig11 and Ig12 of the insulated gate type power semiconductor element as shown in FIG. Becomes larger than the on-gate currents Ig11 and Ig12 in a healthy state. Similarly, the off-gate currents Ig21 and Ig22 of the insulated gate power semiconductor element are also larger than the off-gate currents Ig21 and Ig22 in a healthy state as shown in FIG. 5B.

Table 1 is a table showing this characteristic of the gate current when the semiconductor element is short-circuited. That is, the ratio of on-gate currents Ig11 and Ig12 and off-gate currents Ig21 and Ig22 at the time of a short circuit failure and a healthy state and the availability of detection are shown.

  The short circuit failure detection unit 17 detects the state at the time of this short circuit failure. That is, when the on-gate current Ig1 or the off-gate current Ig2 of the insulated gate power semiconductor element is larger than the current at the time of soundness, it is detected as a short-circuit failure of the insulated gate power semiconductor element. In this case, in order to improve the accuracy of short-circuit fault detection, the number of determinations may be set so that a short-circuit fault is determined when the same phenomenon continues a plurality of times. Further, when both the on-gate current Ig1 and the off-gate current Ig2 are larger than the current at the time of health, it may be detected as a short-circuit failure of the insulated gate type power semiconductor element.

  Next, a disconnection failure detection method in the disconnection failure detection unit 16 will be described. FIG. 6 is an explanatory diagram of on-gate current and off-gate current at the time of disconnection failure on the collector side of the insulated gate type power semiconductor element, FIG. 6 (a) is an explanatory diagram of on-gate currents Ig11 and Ig12, and FIG. ) Is an explanatory diagram of the off-gate currents Ig21 and Ig22.

  As shown in FIG. 6A, if a disconnection failure occurs at the F1 point on the collector side of the insulated gate type power semiconductor element, a disconnection state occurs between the collector C and the emitter E, but the gate G and the emitter. Between E, the state is almost the same as the healthy state. Therefore, when the gate voltage Vge is applied between the gate G and the emitter E, the on-gate currents Ig11 and Ig12 similar to those in the normal state flow.

  On the other hand, the off-gate currents Ig21 and Ig22 are smaller than the off-gate currents Ig21 and Ig22 in a healthy state, as shown in FIG. 6B. In a healthy state, the charge accumulated between the collector C and the emitter E flows while being superimposed on the off-gate currents Ig21 and Ig22 when the insulated gate power semiconductor element is conducting. This is because when a disconnection failure occurs at the point F1, no charge is accumulated between the collector C and the emitter E, so that there is no charge superimposed on the off-gate currents Ig21 and Ig22.

Table 2 is a table showing the characteristics of the gate current when the semiconductor element breaks down on the collector side. That is, the ratio of the on-gate currents Ig11 and Ig12 and the off-gate currents Ig21 and Ig22 between the disconnection failure and the healthy state on the collector side and the possibility of detection are shown.

  The disconnection failure detection unit 16 detects the state at the time of the disconnection failure on the collector side. That is, when the on-gate current Ig1 (Ig11, Ig12) of the insulated gate type power semiconductor element is substantially the same as the current during the healthy state and the off-gate current Ig2 (Ig21, Ig22) is smaller than the current during the healthy state, the insulated gate type It is detected as a disconnection failure on the collector side of the power semiconductor element.

  FIG. 7 is an explanatory diagram of on-gate current and off-gate current at the time of disconnection failure on the emitter side of the insulated gate type power semiconductor device, FIG. 7 (a) is an explanatory diagram of on-gate currents Ig11 and Ig12, and FIG. ) Is an explanatory diagram of the off-gate currents Ig21 and Ig22.

  As shown in FIG. 7 (a), if a disconnection failure occurs at point F2 on the emitter side of the insulated gate type power semiconductor element, the collector C and the emitter E are disconnected, and the gate G and the emitter E During this period, the wire is disconnected. Therefore, even when the gate voltage Vge is applied between the gate G and the emitter E, the on-gate currents Ig11 and Ig12 hardly flow. In the case of complete disconnection, the on-gate currents Ig11 and Ig12 are zero. Similarly, as shown in FIG. 7B, the off-gate currents Ig21 and Ig22 hardly flow.

Table 3 is a table showing the characteristics of the gate current when the semiconductor element breaks down on the emitter side. That is, the ratio of the on-gate currents Ig11 and Ig12 and the off-gate currents Ig21 and Ig22 between the disconnection failure and the sound state on the emitter side and the possibility of detection are shown.

  The disconnection failure detection unit 16 detects the state at the time of the disconnection failure on the emitter side. That is, when the on-gate current Ig1 (Ig11, Ig12) and the off-gate current Ig2 (Ig21, Ig22) of the semiconductor element are smaller than the current at the normal state, it is detected as a disconnection failure on the emitter side of the semiconductor element.

  As described above, the disconnection failure detection unit 16 does not change the on-gate current flowing from the gate drive circuit 13 to the gate G, but detects that the off-gate current flowing from the gate G to the gate drive circuit 13 decreases. When it is determined that the on-gate current flowing from the gate drive circuit 13 to the gate G decreases and the off-gate current flowing from the gate G to the gate drive circuit 13 becomes almost zero, It is determined that this is a disconnection failure.

  In addition, when it is not necessary to identify the collector-side disconnection failure or the emitter-side disconnection failure, it is also possible to detect the disconnection failure of the insulated gate type power semiconductor element when the off-gate current is smaller than the normal current. is there.

  According to the embodiment of the present invention, the gate current flowing through the gate G is compared with the current in the normal state without detecting the current in the main circuit (between the collector and the emitter) of the insulated gate type power semiconductor element, and thus the short circuit failure. And disconnection failure can be detected. In addition to detecting short circuit failures in insulated gate type power semiconductor elements, disconnection faults can also be detected, and in the case of disconnection faults, it is possible to determine whether a collector side disconnection fault or an emitter side disconnection fault has occurred. The reliability of detection can be improved.

  Further, when the failure detection device 14 detects a failed semiconductor element, the failure detection device 14 turns off the switch of the failed element and separates the failed semiconductor element from the gate drive circuit. In the case of the gate power supply self-sufficiency method, when a short circuit failure occurs in the semiconductor element, the gate power supply voltage is lowered. However, since the semiconductor element having the short circuit failure is separated from the gate drive circuit, the gate power supply voltage can be prevented from lowering. Therefore, it is possible to avoid an element failure due to repeated incomplete ON / OFF of a healthy semiconductor element. In addition, since the gate power supply can be secured, a healthy semiconductor element can be normally turned on and off, and the operation can be continued by preventing a current flowing in a concentrated manner in the semiconductor element having a short circuit failure. Further, unnecessary gate current inflow to the gate can be prevented for a semiconductor element having a disconnection failure. That is, it is possible to detect a short-circuit failure or a disconnection failure when semiconductor elements are connected in parallel, and to disconnect the failed semiconductor element from the gate drive circuit and continue the operation, thereby improving the reliability of the power converter. .

The lineblock diagram of the power converter concerning an embodiment of the invention. The block block diagram of the failure detection apparatus of the semiconductor element concerning embodiment of this invention. Explanatory drawing of the on-gate current and off-gate current of an insulated gate power semiconductor element. Explanatory drawing of the on-gate current and off-gate current when an insulated gate power semiconductor element is healthy. Explanatory drawing of an on-gate current and an off-gate current when an insulated gate power semiconductor element is at the time of a short circuit failure. Explanatory drawing of an on-gate current and an off-gate current at the time of the disconnection failure on the collector side of an insulated gate power semiconductor element. Explanatory drawing of an on-gate current and an off-gate current at the time of the disconnection failure on the emitter side of an insulated gate type power semiconductor element.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Parallel element group, 12 ... Semiconductor element, 13 ... Gate drive circuit, 14 ... Fault detection apparatus, 15 ... Current detection part, 16 ... Disconnection fault detection part, 17 ... Short-circuit fault detection part

Claims (6)

  In a failure detection device for an insulated gate power semiconductor element that detects a disconnection failure of the insulated gate power semiconductor element, at least an off-gate current flowing from the gate of the insulated gate power semiconductor element to the gate drive circuit is compared with a current under normal conditions. A fault detection device for an insulated gate power semiconductor element, comprising a disconnection fault detection unit for detecting a disconnection fault.   In the failure detection apparatus for an insulated gate power semiconductor element for detecting a short circuit failure or a disconnection failure of the insulated gate power semiconductor element, an on-gate current flowing from the gate drive circuit of the insulated gate power semiconductor element into the gate or the insulated gate power A short-circuit fault detection unit that detects a short-circuit fault by comparing an off-gate current flowing from the gate of the semiconductor element into the gate drive circuit with a current in a healthy state, and an off-gate current flowing from at least the gate of the insulated gate power semiconductor element into the gate drive circuit A failure detection device for an insulated gate type power semiconductor device, comprising: a disconnection failure detection unit that detects a disconnection failure by comparing the current with a current during normal operation. 3. The insulated gate power semiconductor element according to claim 1, wherein the disconnection fault detection unit detects a disconnection fault of the insulated gate power semiconductor element when the off-gate current is smaller than a current at a healthy state. Failure detection device. The disconnection fault detection unit is configured such that when the on-gate current of the insulated gate power semiconductor element is substantially the same as the current at the time of healthy and the off gate current is smaller than the current at the time of healthy, the disconnection on the collector side of the insulated gate type power semiconductor element A failure is detected, and when an on-gate current and an off-gate current of the insulated gate power semiconductor element are smaller than a healthy current, it is detected as a disconnection fault on the emitter side of the insulated gate power semiconductor element. 3. A failure detection apparatus for an insulated gate power semiconductor element according to 1 or 2 . The short-circuit fault detection unit or the disconnection fault detection unit integrates an absolute value of an on-gate current or an off-gate current, and detects a short-circuit fault or a disconnection fault by comparing the integrated value with a predetermined value. The failure detection apparatus for an insulated gate power semiconductor element according to any one of claims 1 to 4 . The predetermined value is a healthy average value of on-gate current or off-gate current of a plurality of insulated gate power semiconductor elements, or a past on-gate current or off-gate current data value of its own insulated gate power semiconductor element. 6. The fault detection device for an insulated gate power semiconductor device according to claim 5, wherein the fault detection device is provided.

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