JP2022133720A - Failure detector, failure detection method and semiconductor switch device - Google Patents

Abstract

To provide a failure detector, failure detection method and semiconductor switch device, capable of detecting states of a plurality of semiconductor element chips connected in parallel to each other.SOLUTION: A failure detector is a failure detector for semiconductor switch device with a plurality of semiconductor element chips for power conversion. The failure detector includes a determination section. The determination section detects occurrence of a failure in one or the plurality of semiconductor element chips, using a detection result of an electric current running through each of the semiconductor element chips arranged in the semiconductor switch device, a detection result with a voltage applied to the plurality of semiconductor element chips and data of determination criterion capable of identifying occurrence of the failure. The plurality of semiconductor element chips are connected in parallel to each other.SELECTED DRAWING: Figure 1B

Description

TECHNICAL FIELD Embodiments of the present invention relate to failure detection devices, failure detection methods, and semiconductor switch devices.

Some semiconductor switch devices are provided with a plurality of semiconductor element chips in one package, and these semiconductor element chips are connected in parallel with each other. However, if the semiconductor switch device is used for a long period of time, the semiconductor element chip may fail, and if the failure progresses further, the semiconductor switch device may not function. It is desired to detect the state of semiconductor element chips by a failure detection device so that the semiconductor switch device does not stop functioning. There was nothing.
For example, a method of detecting a current imbalance between semiconductor element chips and diagnosing a failure has been proposed (see Patent Document 1, etc.). there was a case.

JP 2020-102973 A

A problem to be solved by the present invention is to provide a failure detection device, a failure detection method, and a semiconductor switch device capable of detecting states of a plurality of semiconductor element chips connected in parallel.

A failure detection device according to an embodiment is a failure detection device for a semiconductor switch device including a plurality of semiconductor element chips for power conversion. The failure detection device includes a determination section. The judging section makes it possible to identify the detection result of the current flowing through each semiconductor element chip arranged in the semiconductor switch device, the detection result of the voltage applied to the plurality of semiconductor element chips, and the occurrence of the failure. Using the judgment reference data, it is detected that one or a plurality of semiconductor element chips out of the plurality of semiconductor element chips has failed. The plurality of semiconductor element chips are connected in parallel with each other.

1 is a configuration diagram of a power converter to which the semiconductor switch device of the embodiment is applied; FIG. 1 is a configuration diagram of a semiconductor switch device according to an embodiment; FIG. FIG. 4 is a diagram for explaining a semiconductor switch device of a comparative example; FIG. 4 is a diagram for explaining a method of estimating the deterioration state of the semiconductor switch device according to the embodiment; FIG. 10 is a diagram for explaining a method for estimating the state of deterioration of the semiconductor switch device according to the second embodiment; The block diagram of the semiconductor switch apparatus of 2nd Embodiment. FIG. 10 is a diagram for explaining a second method of estimating the state of deterioration of the semiconductor switch device according to the second embodiment;

A failure detection device, a failure detection method, and a semiconductor switch device according to embodiments will be described below. In the following description, being electrically connected may be simply referred to as "connected". In this specification, "based on XX" means "based on at least XX", and includes cases based on other elements in addition to XX. Furthermore, "based on XX" is not limited to the case of using XX directly, but also includes the case of being based on what has been calculated or processed with respect to XX. "XX" is an arbitrary element (for example, arbitrary information).

The term "semiconductor switch device" as used in this specification includes one unit (module) or a plurality of units (modules) of the same type, and is formed so that these units function as one switch. It's about. The unit includes a plurality of semiconductor device chips connected in parallel with each other. As used herein, a "semiconductor element chip" refers to one containing a single "switching element" or a plurality of similar "switching elements" that function as a switch under control. As used herein, the term "switching element" includes at least one semiconductor switching element that functions as a switch under control.

"Connected in parallel with each other" includes connecting at least two terminals on the main circuit side of the same type of semiconductor switches to each other. In this case, if the semiconductor switch is a MOSFET (metal-oxide-semiconductor field-effect transistor), it means connecting the sources and the drains, respectively. In the case of an IGBT (Insulated Gate Bipolar Transistor), this refers to connecting emitters and collectors, respectively.

In addition to the above, "connected in parallel with each other" may include connecting the control terminals of the same type of semiconductor switches to each other.

(First embodiment)
FIG. 1A is a configuration diagram of a power converter 2 to which the semiconductor switch device 1 of the embodiment is applied.
The power conversion device 2 includes, for example, a converter 3, an inverter 4, a drive current sensor 5, and a control section 6. AC motor M is, for example, an induction motor. The converter 3 and the inverter 4 each have a plurality of semiconductor switch devices 1 .

The converter 3 converts alternating current power (AC) into direct current power (DC) by switching the semiconductor switch device 1 . The converter 3 adjusts the amount of conversion to DC power under the control of the control unit 6 . Inverter 4 converts the DC power supplied from converter 3 into AC power through switching of semiconductor switch device 1 . The inverter 4 adjusts the conversion amount of active power or reactive power under the control of the control unit 6 . The drive current sensor 5 detects currents flowing from the inverter 4 to the windings of the AC motor M, respectively.

An example of current control in the inverter 4 will be described below.
For example, the controller 6 includes a current regulator (ACR) 61 for controlling the inverter 4 . The current regulator 61 controls the inverter 4 so that the difference between the current reference Iref and the current feedback IFBK based on the current detected by the drive current sensor 5 becomes zero. In the power converter 2 having such a configuration, the magnitude of the current flowing through the semiconductor switch device 1 in the inverter 4 is determined by the current reference Iref.

FIG. 1B is a configuration diagram of the semiconductor switch device 1 of the embodiment.
The semiconductor switch device 1 includes semiconductor element chips 10 , 20 and 30 , a determination section 40 , a current sensor 50 and a voltage sensor 60 .

The semiconductor element chip 10 includes switching elements 11 to 14 . The switching elements 11 to 14 are connected in parallel with each other. The semiconductor element chip 20 includes switching elements 21 to 24 . The switching elements 21 to 24 are connected in parallel with each other. The semiconductor element chip 30 includes switching elements 31 to 34 . The switching elements 31 to 34 are connected in parallel with each other. The semiconductor element chips 10, 20, 30 are connected in parallel with each other.

The semiconductor element chips 10, 20 and 30 described above are similarly configured. In this case, the switching elements 11 to 14, the switching elements 21 to 24, and the switching elements 31 to 34 are also switching elements of the same type.

For example, the semiconductor element chip 10 includes a collector terminal 10C, an emitter terminal 10E, a gate terminal 10G, and a reference potential terminal 10VR. The collectors of the switching elements 11 to 14 are connected to the collector terminal 10C. The emitters of the switching elements 11 to 14 are connected to the emitter terminal 10E and the reference potential terminal 10VR, respectively. Gates of the switching elements 11 to 14 are connected to the gate terminal 10G.

The semiconductor element chip 20 has a collector terminal 20C, an emitter terminal 20E, a gate terminal 20G, and a reference potential terminal 20VR. The semiconductor element chip 30 has a collector terminal 30C, an emitter terminal 30E, a gate terminal 30G, and a reference potential terminal 30VR. The internal configuration of the semiconductor element chips 20 and 30 may be the same as the configuration of the semiconductor element chip 10 described above.

The semiconductor switch device 1 includes a positive terminal TBP, which is a power supply terminal, a negative terminal TBN, and an output terminal TBSO for outputting an alarm signal.

Each of the collector terminals 10C, 20C, and 30C is connected to the terminal TBP. Each of the emitter terminals 10E, 20E, and 30E is connected to the terminal TBN.

The current sensor 50 is provided between the terminal TBN and the junction point connected to the emitter terminals 10E, 20E, 30E, respectively, and collectively detects the current flowing between the emitter terminals 10E, 20E, 30E and the terminal TBN. . The current sensor 50 is an example of a current detection unit that collectively detects currents flowing through a plurality of switching elements for power conversion included in the semiconductor element chips 10 , 20 , and 30 .

Voltage sensor 60 detects the voltage between terminal TBP and terminal TBN. For example, the voltage detected by the voltage sensor 60 includes the voltage (saturation voltage) generated between the terminals of the switching element.

The determination unit 40 determines the possibility that the semiconductor switch device 1 will stop functioning based on the current detection result by the current sensor 50 and the voltage detection result by the voltage sensor 60, and the semiconductor switch device 1 will stop functioning. This alarm is output to the output terminal TBSO when it is determined that there is a high possibility of reaching . The determination unit 40 preferably uses a data table in which predetermined characteristic data is recorded based on the normal characteristic for the above determination. Details of this will be described later.

(Regarding assumed failures)
Here, a semiconductor switch device 1Z of a comparative example will be described with reference to FIG.
FIG. 2 is a diagram for explaining a semiconductor switch device 1Z of a comparative example. This semiconductor switch device 1Z does not include the determination section of the present embodiment.

The 12 switching elements in the semiconductor element chip each pass a part of the amount of current required for the semiconductor switch device 1 when they are conductive.

The ideal normal state shown in FIG. 2A is a state in which the required current is divided into 12 equal parts and flows through each switching element.

Degradation over time may cause an OFF failure in some of the plurality of switching elements in the semiconductor element chip as shown in FIG. 2(b). At this time, if the amount of current required for the semiconductor switch device 1 is the same as in the normal state, the current does not flow through the switching element in which the OFF failure occurred, and the current flows through the switching element in the normal state. . For example, if three switching elements out of 12 have an OFF failure, the current flowing through the switching elements in a healthy state is nearly equal to nine. As described above, when an OFF failure occurs in some switching elements, the load on the switching elements in a healthy state increases. As a result, deterioration of the switching elements gradually progresses, and as shown in FIG. 2(c), the number of switching elements leading to OFF failures gradually increases. If left unattended, the semiconductor switch device may be damaged. If the deterioration of the switching elements progresses evenly, the currents flowing through the semiconductor element chips 10, 20, and 30 do not fluctuate. As the number of switching elements that cause an OFF failure increases, the amount of current distributed to the healthy switching elements increases. It should be controlled so that it does not exceed this.

Next, a method for estimating the state of deterioration of the semiconductor switch device according to this embodiment will be described.
The method for estimating the state of deterioration of the semiconductor switch device proposed in this embodiment includes the following method.
Estimation method using detection results relating to the total value of current flowing through each semiconductor element chip, detection results of voltages applied to a plurality of semiconductor element chips, and predetermined characteristic data This will be described below.

A method for estimating the deterioration state of the semiconductor switch device using the current detection result will be described with reference to FIG. 3A. FIG. 3A is a diagram for explaining a method for estimating the state of deterioration of the semiconductor switch device according to the embodiment;

The state shown in FIG. 3A corresponds to (b) of FIG. 2 described above, and is a state in which each of the semiconductor element chips 10, 20, and 30 has failed. For example, the switching elements 12, 21, 32 have an OFF failure.

In this case, the number of switching elements in a normal state is nine. If the current of the semiconductor switch device 1 is divided equally among the switching elements, the magnitude of the current flowing through each of the semiconductor element chips 10, 20, and 30 becomes equal.

The current sensor 50 collectively detects the current of each semiconductor element chip. In this embodiment, variations in the current of each semiconductor element chip are not detected.

The determination unit 40 may compare the magnitude of the current indicated by the detection result of the current sensor 50 with the magnitude of the current indicated by the data of the characteristic table corresponding to the magnitude of the voltage indicated by the detection result of the voltage sensor 60 . For example, the data of this characteristic table are defined in association with the magnitude of the voltage detected by the voltage sensor 60 .

More specifically, at a specific voltage indicated by the detection result of the voltage sensor 60, the determination unit 40 adds the value of the detection result of the current sensor 50 to the magnitude of the current indicated by the data of the characteristic table corresponding to the specific voltage. , it may be determined that the semiconductor switch device 1 is deteriorating.

Determination unit 40 detects the progress of deterioration of semiconductor switch device 1 by the above-described determination method, and outputs detection signal SD1 indicating this.

For example, the determination unit 40 includes a storage unit 401 and a logic operation unit 402 .

The storage unit 401 stores the current (hereinafter referred to as total current) flowing through each semiconductor element chip (10, 20, 30) and the voltage applied to each semiconductor element chip (10, 20, 30) to determine whether a failure occurs. Holds data of criteria that make it identifiable that a has occurred. This criterion is based on a predetermined allowable range of voltage-current characteristics taking into consideration a predetermined derating from the safe operating area (ASO) of each semiconductor element chip (10, 20, 30). The current value defined here corresponds to the above-mentioned total current, and the storage unit 401 preferably holds this as the data of the criterion.

Based on the detection result of the total current flowing through each semiconductor element chip (10, 20, 30) and the detection result of the voltage applied to the plurality of semiconductor element chips (10, 20, 30), the logical operation unit 402 The occurrence of the failure is detected using the judgment reference data (characteristic table data).

More specifically, as described above, each semiconductor element chip (10, 20, 30) includes a plurality of switching elements for power conversion connected in parallel.
Based on the detection result of the total current flowing through each semiconductor element chip (10, 20, 30) and the detection result of the voltage applied to the plurality of semiconductor element chips (10, 20, 30), the logical operation unit 402 , using the data of the criteria, it is detected that the failure of the switching element is likely to lead to a malfunction.

Judgment unit 40 detects the progress of deterioration of semiconductor switch device 1 by the above-described judgment method, and outputs detection signal SD2 indicating this.

According to the above embodiment, the failure detection device (1) detects a failure of the semiconductor switch device 1 including a plurality of semiconductor element chips (10, 20, 30) for power conversion. The determination unit 40 of the failure detection device detects the current flowing through each semiconductor element chip (10, 20, 30) arranged in the semiconductor switch device 1, One or a plurality of semiconductor element chips ( 10, 20, 30) to detect that a failure has occurred. A plurality of semiconductor element chips (10, 20, 30) are connected in parallel with each other. Thereby, the failure detection device can detect the states of the plurality of semiconductor element chips (10, 20, 30) connected in parallel. The semiconductor switch device 1 is an example of a failure detection device, and a part of the semiconductor switch device 1 may include the failure detection device.

(Modification of the first embodiment)
A modification of the embodiment will be described. In the above-described embodiment, an example of the semiconductor switch device 1 including the determination unit 40, the current sensor 50, and the voltage sensor 60 has been described.

In the semiconductor switch device 1 of this modified example, instead of this, part or all of the determination unit 40 , the current sensor 50 , and the voltage sensor 60 may be formed outside the semiconductor switch device 1 .
In this case, the failure detection device may include determination unit 40 and estimate the state of semiconductor switch device 1 using detection result data from current sensor 50 and voltage sensor 60 . In this case, the failure detection device is formed separately from the semiconductor switch device 1, but the same effects as in the embodiment are obtained.

(Second embodiment)
A second embodiment will be described with reference to FIGS. 3B, 4 and 5. FIG.
It should be noted that the example of the present embodiment described below is not limited to being combined with, for example, the method described in Japanese Patent Application Laid-Open No. 2020-102973. By the above combination, it is possible to similarly detect what can be detected by the method described in JP-A-2020-102973, and furthermore, to detect failures that could not be detected by the method described in the same publication. In this case, the semiconductor switch device 1A determines the state of the semiconductor switch device 1A based on the detection results of both the failure detected by the method of the present embodiment and the failure detected by the method described in Japanese Patent Application Laid-Open No. 2020-102973. should be judged. In the following description, a method for detecting a failure when the failure conditions of semiconductor element chips are uniform will be mainly described.

FIG. 4 is a configuration diagram of a semiconductor switch device 1A of the second embodiment.
The semiconductor switch device 1A includes a determination unit 40A and current sensors 51, 52, and 53 instead of the determination unit 40 and the current sensor 50 of the semiconductor switch device 1. FIG.

Current sensor 51 is provided between emitter terminal 10E and terminal TBN, and detects current flowing between emitter terminal 10E and terminal TBN. Current sensor 52 is provided between emitter terminal 20E and terminal TBN, and detects current flowing between emitter terminal 20E and terminal TBN. Current sensor 53 is provided between emitter terminal 30E and terminal TBN, and detects current flowing between emitter terminal 30E and terminal TBN. Each of the current sensors 51 to 53 is an example of a current detection unit that collectively detects currents flowing through a plurality of switching elements for power conversion included in the semiconductor element chips 10, 20, and 30, respectively.

The determination unit 40A includes a first determination unit 41 (current comparison unit), a second determination unit 42 (current comparison unit), and an output unit 43 . The first determination unit 41 performs determination according to a first estimation method, which will be described later. The second determination unit 42 performs determination according to a second estimation method, which will be described later. The output unit 43 performs a logical operation (for example, a logical sum operation) based on the determination result of the first determination unit 41 and the determination result of the second determination unit 42, and one of the determination results is This alarm is output to the output terminal TBSO when it is determined that there is a high possibility that the semiconductor switch device 1 will stop functioning. Details of this will be described later.

(Method for estimating deterioration state of semiconductor switch device related to assumed failure)
Next, a method for estimating the state of deterioration of the semiconductor switch device according to this embodiment will be described.
The proposed prediction method can be broadly classified into the following two types.
・Estimation method (first estimation method) using detection results of current flowing in each semiconductor element chip
An estimation method (second estimation method) using detection results of current flowing through each semiconductor element chip and detection results of voltages applied to a plurality of semiconductor element chips
These will be described in order below.

With reference to FIG. 3B, a first estimation method for estimating the deterioration state of the semiconductor switch device using the current detection result will be described. FIG. 3B is a diagram for explaining a method of estimating the deterioration state of the semiconductor switch device according to the second embodiment;

The state shown in FIG. 3B is a state in which the semiconductor element chips 10 and 30 are in a healthy state, and the switching elements 21 to 23 in the semiconductor element chip 20 have an OFF failure. Note that the switching element 24 does not have an OFF failure.

In this case, the number of switching elements in a normal state is nine. If the current of the semiconductor switch device 1 is divided equally among the switching elements, and if the magnitude of the current flowing through the semiconductor element chip 20 is 1, then the magnitude of the current flowing through each of the semiconductor element chips 10 and 30 is becomes 4.

Since the current sensors 51 to 53 detect the current of each semiconductor element chip, it is possible to detect variations in the current.

Based on the detection results of the current sensors 51 to 53, the first determination section 41 of the determination section 40A may compare and detect the magnitude of the current indicated by the detection results.

More specifically, the first determination unit 41 may determine that the deterioration of the semiconductor switch device 1 is progressing when the values of the detection results of the current sensors 51 to 53 differ by a predetermined value or more.

Alternatively, the first determination unit 41 may determine that the deterioration of the semiconductor switch device 1 is progressing when there is a difference of a predetermined value or more between the maximum value and the minimum value of the detection results of the current sensors 51 to 53 .

Alternatively, the first determination unit 41 determines that the deterioration of the semiconductor switch device 1 occurs when the values of the detection results of the current sensors 51 to 53 differ from the average value (or central value) of the detection results by a predetermined value or more. You can judge that it is progressing.

The first determination unit 41 detects a state in which deterioration of the semiconductor switch device 1 is progressing by any of the determination methods described above, and outputs a detection signal SD1 indicating this.

A second estimation method for estimating the deterioration state of the semiconductor switch device 1A using the current detection result will be described with reference to FIG. FIG. 5 is a diagram for explaining a second estimation method of the deterioration state of the semiconductor switch device 1A of the embodiment.

The state shown in FIG. 5 is a state in which the switching elements in the semiconductor element chips 10, 20 and 30 have an OFF failure. For example, assume that the switching elements 11, 22, and 34 have an OFF failure. According to this, the number of switching elements in which an OFF failure has occurred is one for each semiconductor element chip.

In the above case, since the currents of the semiconductor element chips 10, 20, and 30 do not fluctuate, detection is difficult with the above-described first estimation method using current comparison.

Therefore, in the second estimation method, this can be estimated by making a determination using the voltage as well.

It is assumed that the ON resistances of the switching elements in the healthy state are the same when conducting.
If all the switching elements are in a healthy state, the current per switching element is 1/12th of the total because 12 are connected in parallel.

However, as the number of OFF-failure switching elements increases, the current flowing through each switching element increases, and accordingly the voltage (saturation voltage) generated between the terminals of each switching element increases. Therefore, loss in each switching element increases.

The second determination unit 42 of the determination unit 40A preferably detects the magnitude of the current indicated by the detection results by comparing the detection results of the current sensors 51 to 53 and the detection result of the voltage sensor 60 based on the detection results. In other words, the second determination unit 42 determines the detection result of the current flowing through each of the semiconductor element chips (10, 20, 30) arranged in the semiconductor switch device 1 and the plurality of semiconductor element chips (10, 20, 30). ) and the detection result, it is detected that one or a plurality of semiconductor element chips (10, 20, 30) out of the plurality of semiconductor element chips (10, 20, 30) has failed. do.

For example, the second determination section 42 includes a storage section 421 and a logical operation section 422 .

The storage unit 421 can identify the occurrence of a failure from the relationship between the current flowing through each semiconductor element chip (10, 20, 30) and the voltage applied to each semiconductor element chip (10, 20, 30). Holds the data of the judgment criteria. It is preferable that this judgment criterion determines a predetermined allowable range of voltage-current characteristics in consideration of a predetermined derating from the safe operating area (ASO) of each semiconductor element chip (10, 20, 30). It is preferable that this data be held as determination reference data in the storage unit 421. The determination reference data in the storage unit 421 is data for each semiconductor element chip (10, 20, 30), whereas the storage unit 421 described above stores the data as the determination reference. The data of the criterion of 401 is different in that it is the data as the semiconductor switch device 1 .

The logical operation unit 422 determines based on the detection result of the current flowing through each semiconductor element chip (10, 20, 30) and the detection result of the voltage applied to the plurality of semiconductor element chips (10, 20, 30). The reference data is used to detect that the fault has occurred.

More specifically, as described above, each semiconductor element chip (10, 20, 30) includes a plurality of switching elements for power conversion connected in parallel.
Based on the detection result of the current flowing through each semiconductor element chip (10, 20, 30) and the detection result of the voltage applied to the plurality of semiconductor element chips (10, 20, 30), the logical operation unit 422 Criterion data is used to detect an increased possibility of failure due to switching element failure.

The second determination unit 42 detects a state in which the deterioration of the semiconductor switch device 1 is progressing by the above determination method, and outputs a detection signal SD2 indicating this.

According to the above embodiment, the failure detection device (1A) detects a failure of the semiconductor switch device 1 including a plurality of semiconductor element chips (10, 20, 30) for power conversion. The determination unit 40A of the failure detection device detects the current flowing through each of the semiconductor element chips (10, 20, 30) arranged in the semiconductor switch device 1, and the plurality of semiconductor element chips (10, 20, 30) Using the applied voltage and the detection result, it is detected that one or more of the plurality of semiconductor element chips (10, 20, 30) has failed. A plurality of semiconductor element chips (10, 20, 30) are connected in parallel with each other. Thereby, the failure detection device can detect the states of the plurality of semiconductor element chips (10, 20, 30) connected in parallel. The semiconductor switch device 1A is an example of a failure detection device, and the failure detection device may be included in a part of the semiconductor switch device 1A.

According to at least one embodiment described above, the failure detection device detects a failure of a semiconductor switch device including a plurality of semiconductor element chips for power conversion. The failure detection device includes a determination section. The judging unit has a detection result of a current flowing through each semiconductor element chip arranged in the semiconductor switch device, a detection result of a voltage applied to a plurality of semiconductor element chips, and a judgment standard for distinguishing occurrence of a failure. , the occurrence of a failure in one or a plurality of semiconductor element chips out of the plurality of semiconductor element chips is detected. A plurality of semiconductor element chips are connected in parallel with each other. Thereby, the failure detection device can detect the states of a plurality of semiconductor element chips connected in parallel. The semiconductor switch device is an example of the failure detection device, and the failure detection device may be included in a part of the semiconductor switch device.

While several embodiments of the invention have been described, these embodiments have been presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, as well as the scope of the invention described in the claims and equivalents thereof.

For example, the determination unit 40 may include at least the second determination unit 42 out of the first determination unit 41 and the second determination unit 42 .

1, 1A semiconductor switch device (failure detection device)
2 power conversion device 3 converter 4 inverter 5 drive current sensor 6 control unit M AC motors 10, 20, 30 semiconductor element chips 11 to 14, 22 to 24, 31 to 34 switching elements 40, 40A determination unit 41 first determination unit 42 Second determination unit 43 Output units 50 to 53 Current sensor (current detection unit)
60 voltage sensor (voltage detector)

Claims (9)

A failure detection device for a semiconductor switch device comprising a plurality of semiconductor element chips for power conversion,
Detection results of the current flowing through each semiconductor element chip arranged in the semiconductor switch device, detection results of the voltage applied to the plurality of semiconductor element chips, and judgment reference data that enables identification of the occurrence of the failure. and a determination unit that detects that one or more of the plurality of semiconductor element chips has failed,
wherein the plurality of semiconductor element chips are connected in parallel with each other;
Fault detection device. a storage unit that holds determination criterion data that enables identification of the occurrence of the failure based on the relationship between the current flowing through each of the semiconductor element chips and the voltage applied to the plurality of semiconductor element chips;
The determination unit
detecting the occurrence of the failure using the determination criteria data based on the detection result of the current flowing through each of the semiconductor element chips and the detection result of the voltage applied to the plurality of semiconductor element chips;
The failure detection device according to claim 1. Each semiconductor element chip includes a plurality of switching elements for power conversion connected in parallel with each other,
The determination unit
Based on the result of detection of the current flowing through each of the semiconductor element chips and the result of detection of the voltage applied to the plurality of semiconductor element chips, the failure of the switching element results in a functional stop using the determination reference data. detect an increased likelihood of
The failure detection device according to claim 2. The semiconductor switch device is
4. The failure detection device according to claim 3, further comprising a current detection unit that collectively detects currents flowing through the plurality of switching elements for power conversion included in the semiconductor element chip. The semiconductor switch device is
4. The failure detection device according to claim 3, further comprising a current detection unit that detects currents flowing through the plurality of switching elements for power conversion included in the semiconductor element chip for each semiconductor element chip. The data of the criterion that makes it possible to identify that the failure has occurred includes:
Data of a characteristic table defined in correspondence with the magnitude of the voltage of the voltage detection result is included,
The failure detection device according to any one of claims 1 to 5. The semiconductor switch device has the plurality of semiconductor element chips connected in parallel inside thereof.
The failure detection device according to any one of claims 1 to 6. A failure detection method for a semiconductor switch device including a plurality of semiconductor element chips for power conversion, comprising:
Detection results of the current flowing through each semiconductor element chip arranged in the semiconductor switch device, detection results of the voltage applied to the plurality of semiconductor element chips, and judgment reference data that enables identification of the occurrence of the failure. detecting that a failure has occurred in any of the plurality of semiconductor element chips based on
wherein the plurality of semiconductor element chips are connected in parallel with each other;
Fault detection method. a plurality of semiconductor element chips connected in parallel with each other;
Using the detection result of the current flowing through each of the semiconductor element chips, the detection result of the voltage applied to the plurality of semiconductor element chips, and the data of the criterion for identifying the occurrence of the failure, the plurality of A semiconductor switch device comprising: a determination unit for detecting that one or a plurality of semiconductor element chips among the semiconductor element chips of .

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