JP2018011253A - Semiconductor device state discrimination apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress erroneous discrimination of a semiconductor device state such as the presence/absence of a failure in a temperature-sensitive diode as a result by suppressing influences of external noise as further as possible in a semiconductor device state discrimination apparatus.SOLUTION: A control apparatus 12 comprises a second determination part 52f for determining that a determination of an overheat state of a switching element 41 by a first determination part 52e is an erroneous determination in a case where a detection temperature Th calculated by a voltage/temperature conversion part 51c is higher than a detection temperature determination threshold Th_th and an amount ΔTh of change of the detection temperature Th calculated by an amount-of-change calculation part 52d is greater than a first amount-of-change determination threshold ΔTh_th1 that is set to a value greater than a temperature rising amount for a temperature of the switching element 41 to rise during a control cycle time TM when actuating the switching element 41.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a semiconductor device state determination apparatus.

As one type of semiconductor device state determination apparatus, one disclosed in Patent Document 1 is known. As shown in FIG. 1 of Patent Document 1, the overheat protection circuit (semiconductor device state determination device) of Patent Document 1 includes a temperature-sensitive diode (12) formed on the same substrate (26) as the switching element (24). The first constant current (Ia) is supplied to the temperature sensing diode in response to the switching element being turned on, and the temperature sensing diode is supplied to the temperature sensing diode from the first constant current in response to at least a part of the switching element being turned off. A current supply unit (14) for supplying a small second constant current (Ib) and an abnormality detection signal when a detection value when the first constant current (Ia) is supplied is smaller than a threshold for overheating detection. A voltage detector (16) that outputs an abnormality detection signal when the detected value when the second constant current (Ib) is supplied is smaller than a threshold value indicating a failure of the temperature sensitive diode; Current is supplied to the voltage detector When the abnormality detection signal is output, and a clear means for turning off the switching element (18), the.
According to this, overheat detection can be performed in response to the switching element (24) being turned on. In addition, when overheating is detected, the first constant current (Ia) larger than the second constant current (Ib) is supplied to the temperature sensitive diode (12), so that the potential level of the forward drop voltage is increased thereby increasing the noise margin. Can be made less susceptible to external noise. That is, malfunctions due to external noise can be reduced as compared with the prior art.

Moreover, the overheat protection circuit of patent document 1 determines the presence or absence of a failure of the temperature sensitive diode (12) based on the drive control signal and the output signal of the voltage detector (16), and outputs a determination signal according to the determination result. A failure diagnosis unit (20) for outputting is provided, and the failure diagnosis unit (20) has a detection value when the second constant current (Ib) is supplied smaller than a threshold value indicating a failure of the temperature sensitive diode (12). In addition, a failure signal indicating that a failure has occurred in the temperature sensitive diode (12) is output as the determination signal.
According to this, in response to the switching element (24) being turned off, the second constant current (Ib) is supplied to the temperature sensing diode (12), and the presence or absence of a failure in the temperature sensing diode (12) is checked. Can be determined.

Japanese Patent Laid-Open No. 2014-039220

  In the overheat protection circuit according to Patent Document 1, malfunctions due to external noise with respect to a detection value when an input signal to the voltage detection unit (16) and a second constant current (Ib) are supplied are reduced, and a temperature sensitive diode The presence / absence of a failure in (12) is determined. However, the malfunction due to the external noise cannot be reduced completely, and the failure diagnosis unit (20) causes the temperature sensing diode due to the external noise with respect to the detected value when the second constant current (Ib) is supplied. There is a risk of misjudging the presence or absence of a failure in (12).

  The present invention has been made to solve the above-described problems. In the semiconductor device state determination apparatus, the influence of external noise is suppressed as much as possible, and thus erroneous determination of the semiconductor device state such as the presence or absence of a temperature-sensitive diode failure is suppressed. For the purpose.

  In order to solve the above-described problem, a semiconductor device state determination apparatus according to claim 1 is provided with a plurality of switching elements for switching energization / non-energization to a controlled object, and the temperature of each switching element provided adjacent to each switching element. A semiconductor device state determination apparatus for determining a state related to a semiconductor device including a plurality of temperature sensing diodes for detection, and acquiring a forward voltage of each temperature sensing diode according to the temperature of each switching element From the acquisition unit, the acquisition value acquired by the acquisition unit, the detection temperature calculation unit that calculates the detection temperature of the switching element corresponding to the acquisition value for each control cycle time, and the control cycle from the acquisition value acquired by the acquisition unit A change amount calculation unit that calculates the change amount of the detected temperature of the switching element corresponding to the change amount of the acquired value every time, and a detection temperature calculation unit The detected temperature calculated by the detected temperature calculation unit is greater than the detected temperature determination threshold. In addition, the change amount of the detected temperature calculated by the change amount calculation unit is set to a value larger than the temperature increase amount at which the temperature of the switching element rises during the control cycle time when the switching element is operated. A second determination unit that determines that the determination by the first determination unit that the switching element is in an overheated state is an erroneous determination when the change amount determination threshold value is larger.

  In the semiconductor device state determination apparatus, the change amount of the detected temperature calculated by the change amount calculation unit is set to a value larger than the temperature increase amount during which the switching element temperature rises during the control cycle time when the switching element is operated. The case where it is larger than the first change amount determination threshold, that is, the acquired value acquired by the acquiring unit is not an actual acquired value but external noise. Therefore, the second determination unit acquires the detection temperature when the detection temperature calculated by the detection temperature calculation unit is larger than the detection temperature determination threshold and the change amount of the detection temperature is larger than the first change amount determination threshold. The obtained acquired value can be determined to be external noise, and therefore, even if the first determination unit determines that the switching element is in an overheated state, it can be determined that the determination is an erroneous determination. . As a result, the semiconductor device state determination apparatus can suppress the influence of external noise as much as possible, and thus suppress erroneous determination of the semiconductor device state such as the presence or absence of a temperature sensitive diode failure.

1 is a schematic diagram showing an embodiment of a semiconductor device state determination apparatus according to the present invention. It is a general | schematic block diagram of the inverter apparatus shown in FIG. It is a figure which shows the change of the detected temperature of three patterns. It is a flowchart which the control apparatus shown in FIG. 2 performs. It is a time chart which shows an example of overheating detection and overheating erroneous detection. It is a time chart which shows detected temperature and forward voltage when a temperature-sensitive diode is out of order.

  Hereinafter, an embodiment in which a semiconductor device state determination apparatus according to the present invention is applied to an inverter apparatus will be described. Inverter device 10 of this embodiment supplies direct current power of battery BAT to motor 20 which is a rotating electric machine of a hybrid vehicle, or charges battery BAT with electricity generated by motor 20. The motor 20 is, for example, a three-phase brushless motor. As shown in FIG. 1, the inverter device 10 includes a cooling device 30.

  As shown in FIG. 2, the inverter device 10 includes a semiconductor device 11 and a control device 12 that is a semiconductor device state determination device.

  The semiconductor device 11 includes a plurality of switching elements 41 that switch between energization / non-energization of the motor 20 (control target) and a plurality of temperature sensing elements that are adjacent to each switching element 41 and detect the temperature of each switching element 41. And a diode 42. The semiconductor device 11 includes six switching elements 41 (the number corresponding to the upper and lower arms in three phases), but only one is schematically shown in FIG. Omitted. Similarly, only one temperature sensitive diode 42 is schematically shown, and other temperature sensitive diodes are omitted.

  The semiconductor device 11 includes a free-wheeling diode 43 connected in reverse parallel to the switching element 41. The reflux diode 43 is arranged in parallel between the collector and the emitter of the switching element 41. Similarly, only one free-wheeling diode 43 is schematically shown, and the other free-wheeling diodes are omitted.

  The switching element 41 is, for example, an IGBT (Insulated Gate Bipolar Transistor). The switching element 41 is switched on / off according to a gate signal input to the gate from the gate signal creation unit 51a.

  The temperature sensing diode 42 is connected to a constant current circuit 51d that sets a current value flowing through the temperature sensing diode 42 to a predetermined current value. The constant current circuit 51d is provided in the driving driver 51.

  The forward voltage value of the temperature sensitive diode 42 and the temperature of the switching element 41 have a correlation in which the forward voltage value of the temperature sensitive diode 42 decreases as the temperature of the switching element 41 increases. The correlation is derived by actual measurement by experiments or the like in advance. The correlation is stored in the control device 12 (voltage-temperature conversion unit 51c). The forward voltage value of the temperature sensing diode 42 is input to the acquisition unit 51b.

  The control device 12 includes a driver 51 for driving the switching element 41 and a CPU 52 that controls the driver 51 for driving. The driving driver 51 includes a gate signal creation unit 51a, an acquisition unit 51b, a voltage-temperature conversion unit 51c, and a constant current circuit 51d.

The gate signal creation unit 51a acquires a PWM signal from the PWM signal creation unit 52b, creates a gate signal from the PWM signal, and outputs the gate signal to the gate of each switching element 41. Each switching element 41 is controlled to be turned on / off based on a gate signal.
The acquisition unit 51 b acquires the forward voltage of each temperature sensitive diode 42 according to the temperature of each switching element 41.

The voltage-temperature converter 51c is a detected temperature calculator that calculates (converts) the detected temperature of the switching element 41 corresponding to the acquired value for each control cycle time TM from the acquired value acquired by the acquiring unit 51b. That is, the voltage-temperature conversion unit 51c acquires the forward voltage of the temperature-sensitive diode 42 from the acquisition unit 51b, and uses the temperature of the switching element 41 corresponding to the forward voltage acquired using the correlation as the detected temperature. calculate.
The constant current circuit 51 d is a circuit for supplying a constant current to the temperature sensitive diode 42.

  The CPU 52 includes a drive signal generation unit 52a, a PWM signal generation unit 52b, an input unit 52c, a change amount calculation unit 52d, a first determination unit 52e, a second determination unit 52f, a third determination unit 52g, a fourth determination unit 52h, and A fifth determination unit 52i is provided.

The drive signal creation unit 52a creates a drive signal that is a signal for driving the motor 20 to be controlled. The PWM signal creation unit 52b acquires a drive signal from the drive signal creation unit 52a, and creates a PWM signal for the switching element 41 (motor 20) based on the drive signal.
The input unit 52c acquires an acquired value (forward voltage of the switching element 41) from the acquiring unit 51b, or acquires a detected temperature of the switching element 41 from the voltage-temperature converting unit 51c.
The change amount calculation unit 52d calculates the change amount ΔTh of the detected temperature of the switching element 41 corresponding to the change amount of the acquired value for each control cycle time TM from the acquired value acquired by the acquiring unit 51b.

The first determination unit 52e determines that the switching element 41 is in an overheated state when the detected temperature Th calculated by the voltage-temperature conversion unit 51c (detected temperature calculation unit) is greater than the detected temperature determination threshold Th_th. Specifically, the first determination unit 52e acquires the detection temperature Th calculated by the voltage-temperature conversion unit 51c from the input unit 52c, and compares the acquired detection temperature Th with the detection temperature determination threshold Th_th. For example, the detection temperature determination threshold Th_th is set to a temperature lower than the upper limit temperature of the temperature range in which the normal operation of the switching element 41 is guaranteed.
Further, the first determination unit 52e acquires the change amount ΔTh of the detected temperature from the change amount calculation unit 52d, the change amount ΔTh of the detected temperature is smaller than the first change amount determination threshold value ΔTh_th1, and the detected temperature Th is the detected temperature. When it is larger than the determination threshold Th_th, it is more preferable to determine that the switching element 41 is in an overheated state.

  The second determination unit 52f determines that the change amount ΔTh of the detected temperature calculated by the change amount calculation unit 52d is higher than the temperature increase amount during which the temperature of the switching element 41 rises during the control cycle time TM when the switching element 41 operates. When it is larger than the first change amount determination threshold ΔTh_th1 set to a large value, it is determined that the determination by the first determination unit 52e that the switching element 41 is in an overheated state is an erroneous determination. Specifically, the second determination unit 52f acquires the change amount ΔTh of the detected temperature from the change amount calculation unit 52d, and compares the acquired change amount ΔTh of the detected temperature with the first change amount determination threshold value ΔTh_th1.

  Further, the second determination unit 52f acquires the change amount ΔTh of the detected temperature from the change amount calculation unit 52d, the change amount ΔTh of the detected temperature is larger than the first change amount determination threshold value ΔTh_th1, and the detected temperature Th is the detected temperature. When it is larger than the determination threshold Th_th, it is more preferable to determine that the determination by the first determination unit 52e that the switching element 41 is in an overheated state is an erroneous determination (error overheat detection due to noise).

  Furthermore, the second determination unit 52f acquires the acquired value (the forward voltage of the temperature-sensitive diode 42) from the acquisition unit 51b, the detected temperature change amount ΔTh is greater than the first change amount determination threshold value ΔTh_th1, and the detected temperature When Th is larger than the detected temperature determination threshold Th_th and the acquired value (Vf) is larger than the acquired value determination threshold Vf_th, the determination that the switching element 41 is overheated by the first determination unit 52e is erroneously determined (noise) It is more preferable to determine that it is an erroneous overheat detection).

  The first change amount determination threshold ΔTh_th1 is a temperature increase amount (for example, in FIG. 3) in which the temperature of the switching element 41 rises during the control cycle time TM when the cooling device 30 is normal and the switching element 41 is activated. It is set to a value larger than ΔTh_b). Further, the first change amount determination threshold value ΔTh_th1 is a temperature increase amount (for example, when the temperature of the switching element 41 rises during the control cycle time TM when the switching device 41 is in operation and the cooling device 30 has failed). In FIG. 3, it is set to a value larger than ΔTh_c). Further, the detected temperature rise amount ΔTh_a related to noise is larger than the normal detected temperature rise amount ΔTh_b and the detected temperature rise amount ΔTh_c when the cooling device 30 fails.

FIG. 3 shows three types of temperature changes from the previous processing time tn-1. The first is an increase in the detected temperature of the switching element 41 when the cooling device 30 is normal and the switching element 41 is in a normal operation, and the rate of increase (change rate) is the smallest. The second is an increase in the detected temperature of the switching element 41 when the cooling device 30 fails and when the switching element 41 operates normally. In this case, since the cooling device 30 is out of order, the rate of increase (temperature increase amount for each control cycle time) is larger than when the cooling device 30 is normal. The third is an increase in the detection temperature related to noise, and noise is detected as a temperature. Therefore, the increase rate is larger than the increase rate due to the actual temperature increase. Further, the amount of change related to noise in the control cycle time TM, which is a relatively short time, is larger than the actual temperature change.
As can be understood from the foregoing, it is possible to determine from the amount of change in the control cycle time TM whether the increase in the detected temperature is due to noise or the actual temperature increase.

  The third determination unit 52g is configured such that the change amount ΔTh of the detected temperature calculated by the change amount calculation unit 52d is smaller than the first change amount determination threshold ΔTh_th1 and smaller than the first change amount determination threshold ΔTh_th1. When it is larger than the second change amount determination threshold ΔTh_th2, the cooling device 30 is determined to be in failure. Specifically, the third determination unit 52g acquires the change amount ΔTh of the detected temperature from the change amount calculation unit 52d, the acquired change amount ΔTh of the detected temperature, the first change amount determination threshold value ΔTh_th1, and the second change. The amount determination threshold value ΔTh_th2 is compared. The second change amount determination threshold value ΔTh_th2 is set to a value smaller than the first change amount determination threshold value ΔTh_th1. The second change amount determination threshold value ΔTh_th2 is set to a value larger than the normal temperature increase amount ΔTh_b of the detected temperature and to a value smaller than the temperature increase amount ΔTh_c of the detected temperature when the cooling device 30 fails.

  The fourth determination unit 52h is configured such that the change amount ΔTh of the detected temperature calculated by the change amount calculation unit 52d is higher than the temperature increase amount at which the temperature of the switching element 41 rises during the control cycle time TM when the switching element 41 is activated. When the first change amount determination threshold ΔTh_th1 that is set to a large value is larger than the acquired value acquired by the acquisition unit 51b and smaller than the acquired value determination threshold Vf_th, the temperature sensitive diode 42 is abnormal. Judge that there is. Specifically, the fourth determination unit 52h acquires the change amount ΔTh of the detected temperature from the change amount calculation unit 52d, and compares the acquired change amount ΔTh of the detected temperature with the first change amount determination threshold value ΔTh_th1. . The fourth determination unit 52h acquires the acquired value from the acquiring unit 51b (via the input unit 52c), and compares the acquired acquired value with the acquired value determination threshold value Vf_th.

Further, the fourth determination unit 52h acquires the detection temperature Th calculated by the voltage-temperature conversion unit 51c from the input unit 52c, the detection temperature Th is greater than the detection temperature determination threshold Th_th, and the change amount ΔTh of the detection temperature Is more than the first change amount determination threshold value ΔTh_th1 and it is more preferable to determine that the temperature-sensitive diode 42 is abnormal when the acquired value is smaller than the acquired value determination threshold value Vf_th.
The acquired value determination threshold value Vf_th is a value smaller than the forward voltage value of the temperature-sensitive diode and the diode used, and is set to a value of 0 V or more. The acquired value determination threshold value Vf_th may be set to a value larger than 0V.

  The fifth determination unit 52i has a voltage − after a predetermined time has elapsed since the second determination unit 52f determined that the determination by the first determination unit 52e that the switching element 41 is in an overheated state was an erroneous determination. When the detected temperature Th calculated by the temperature converter 51c is larger than the detected temperature determination threshold Th_th, it is determined that the electric wire 61 (described later) connecting the driving driver 51 and the CPU 52 is abnormal.

  The electric wire 61 is comprised at least from the electric wire 61a, the electric wire 61b, and the electric wire 61c. The electric wire 61a connects the PWM signal generation unit 52b and the gate signal generation unit 51a, the electric wire 61b connects the acquisition unit 51b and the input unit 52c, and the electric wire 61c includes the voltage-temperature conversion unit 51c and the input unit 52c. And connect.

  The electric wire 62 includes at least an electric wire 62a, an electric wire 62b, an electric wire 62c, and an electric wire 62d. The electric wire 62a connects the gate signal generator 51a and the gate of the switching element 41, the electric wire 62b connects the constant current circuit 51d (power source V) and the anode of the temperature-sensitive diode 42, and the electric wire 62c The cathode of the diode 42 is grounded, and the electric wire 62d connects the electric wire 62b and the acquisition unit 51b.

  The cooling device 30 cools the semiconductor device 11 and thus the inverter device 10. As shown in FIG. 1, the cooling device 30 includes a circulation path 31, a pump 32, a heat exchange unit 33, and a radiator 34. The circulation path 31 is a flow path (tube) through which the refrigerant that exchanges heat in the heat exchange unit 33 and the radiator 34 circulates. The pump 32 is a delivery device that causes the refrigerant to flow through the circulation path 31. The heat exchanging unit 33 exchanges heat between the semiconductor device 11 and thus the inverter device 10 and the refrigerant, and the heat of the semiconductor device 11 and thus the inverter device 10 is recovered by the refrigerant. The radiator 34 exchanges heat between the outside air and the refrigerant, for example, and recovers the heat of the refrigerant to the outside air.

  Next, the operation of the semiconductor device state determination apparatus will be described with reference to the flowchart of FIG. The control device 12 executes a program corresponding to the flowchart shown in FIG. 4 for each control cycle time TM. The control cycle time TM is several microseconds.

In step S102, the control device 12 performs switching corresponding to the acquired value for each control cycle time TM from the acquired value acquired by the acquiring unit 51b in the same manner as the detected temperature calculating unit (voltage-temperature converting unit 51c) described above. The detection temperature Th of the element 41 is calculated.
In step S104, the control device 12 detects the switching element 41 corresponding to the change amount of the acquired value for each control cycle time TM from the acquired value acquired by the acquiring unit 51b in the same manner as the change amount calculating unit 52d described above. The temperature change amount ΔTh is calculated. Specifically, the detected temperature change amount ΔTh is calculated by subtracting the previously calculated detected temperature Th (n−1) from the currently calculated detected temperature Th (n).

Similarly to the first determination unit 52e described above, the control device 12 determines that the detected temperature change amount ΔTh is smaller than the first change amount determination threshold value ΔTh_th1 (determined as “YES” in step S106), and the detected temperature Th is When it is larger than the detected temperature determination threshold Th_th (determined as “YES” in step S110), it is determined that the switching element 41 is in an overheated state (step S112).
For example, as shown in the upper diagram of FIG. 5, the control device 12 detects overheating at time t <b> 2 when the detected temperature Th exceeds the detected temperature determination threshold Th_th.

  Similarly to the third determination unit 52g described above, the control device 12 determines that the detected temperature change amount ΔTh is smaller than the first change amount determination threshold value ΔTh_th1 (“YES” in step S106), and the first change amount determination is performed. When larger than the second change amount determination threshold ΔTh_th2 set to a value smaller than the threshold ΔTh_th1 (“NO” in step S108), it is determined that the cooling device 30 is in failure (step S114).

Similarly to the second determination unit 52f described above, the control device 12 has the detected temperature change amount ΔTh larger than the first change amount determination threshold value ΔTh_th1 (“NO” in step S106), and the detected temperature Th is the detected temperature. When the determination value is larger than the determination threshold Th_th (“YES” in step S116) and the acquired value (Vf) is larger than the acquired value determination threshold Vf_th (“NO” in step S118), the switching element by the first determination unit 52e It is determined that the determination that 41 is in an overheated state is an erroneous determination (error overheat detection due to noise) (step S122).
For example, as illustrated in the lower diagram of FIG. 5, at time t <b> 1 when the detected temperature Th exceeds the detected temperature determination threshold Th_th, the control device 12 determines that the overheating error detection due to noise. Thereafter, the control device 12 detects overheating at time t2, which is the time when the detected temperature Th exceeds the detected temperature determination threshold Th_th.

Similarly to the above-described fourth determination unit 52h, the control device 12 has the detected temperature change amount ΔTh larger than the first change amount determination threshold value ΔTh_th1 (“NO” in step S106), and the detected temperature Th is the detected temperature. If it is larger than determination threshold Th_th (“YES” in step S116) and the acquired value is smaller than acquired value determination threshold Vf_th (“YES” in step S118), it is determined that temperature-sensitive diode 42 is abnormal. (Step S120).
For example, as shown in the upper diagram of FIG. 6, at time t <b> 11 when the detected temperature Th exceeds the detected temperature determination threshold Th_th, the control device 12 determines that it is an erroneous detection of overheating due to noise. 6, since the acquired value is smaller than the acquired value determination threshold value Vf_th, it is finally determined that the temperature sensitive diode 42 is abnormal.

  Similarly to the above-described fifth determination unit 52i, the control device 12 starts after a predetermined time has elapsed from the time when the determination by the first determination unit 52e that the switching element 41 is overheated is determined to be an erroneous determination. When the detected temperature Th calculated by the voltage-temperature converter 51c is larger than the detected temperature determination threshold Th_th (“YES” in step S124), the electric wire 61 (described later) that connects the drive driver 51 and the CPU 52 is used. Is determined to be abnormal.

  Note that the control device 12 may stop the inverter device 10 when overheating is detected. At this time, in the case of erroneous detection of overheating due to noise, it is preferable that the control device 12 does not stop the inverter device 10.

  As is clear from the above description, the control device 12 (semiconductor device state determination device) according to the present embodiment includes a plurality of switching elements 41 that switch energization / non-energization of the motor 20 (control target), and each switching element. 41 is a semiconductor device state determination apparatus that determines a state related to the semiconductor device 11 and includes a plurality of temperature sensitive diodes 42 that are adjacent to 41 and detect the temperature of each switching element 41. The control device 12 acquires an acquisition value for each control cycle time TM from an acquisition unit 51b that acquires the forward voltage of each temperature-sensitive diode 42 according to the temperature of each switching element 41 and an acquisition value acquired by the acquisition unit 51b. From the acquired value acquired by the detected temperature calculation part (voltage-temperature conversion part 51c) and the acquisition part 51b which calculate the detected temperature Th of the switching element 41 corresponding to the change amount of the acquired value for each control cycle time TM When the detected temperature Th calculated by the change amount calculating unit 52d that calculates the change amount ΔTh of the detected temperature Th of the corresponding switching element 41 and the voltage-temperature converting unit 51c is larger than the detected temperature determination threshold Th_th, the switching element 41 The detected temperature Th calculated by the first determination unit 52e and the voltage-temperature conversion unit 51c that determines that is in an overheated state is The change amount ΔTh of the detected temperature Th calculated by the change amount calculation unit 52d, which is larger than the output temperature determination threshold Th_th, rises during the control cycle time TM when the switching element 41 is activated. A second determination that the determination by the first determination unit 52e that the switching element 41 is in an overheated state is an erroneous determination when it is greater than the first change amount determination threshold ΔTh_th1 that is set to a value greater than the temperature increase amount. And a determination unit 52f.

  In the control device 12 (semiconductor device state determination device), the change amount ΔTh of the detected temperature Th calculated by the change amount calculating unit 52d is equal to the temperature of the switching element 41 during the operation of the switching element 41 during the control cycle time TM. Is greater than the first change amount determination threshold ΔTh_th1 that is set to a value larger than the temperature rise amount that rises to the time, that is, the acquired value acquired by the acquiring unit 51b is not an actual acquired value but external noise. It is. Therefore, the second determination unit 52f has the detection temperature Th calculated by the voltage-temperature conversion unit 51c larger than the detection temperature determination threshold Th_th, and the change amount ΔTh of the detection temperature Th is larger than the first change amount determination threshold ΔTh_th1. In this case, it can be determined that the acquired value acquired by the acquiring unit 51b is external noise, and even if the first determining unit 52e determines that the switching element 41 is in an overheated state, the determination Can be determined to be an erroneous determination. As a result, the control device 12 can suppress the influence of the external noise as much as possible, and thus suppress erroneous determination of the semiconductor device state such as the presence or absence of the failure of the temperature sensitive diode 42.

  Further, in the control device 12 (semiconductor device state determination device) according to the present embodiment, when the detected temperature Th becomes larger than the detected temperature determination threshold Th_th in a relatively long time due to noise (the temperature is higher on the high temperature side). When the detected temperature Th exceeds the detected temperature determination threshold Th_th, the erroneous determination can be suppressed based on whether or not the change amount ΔTh of the detected temperature Th is larger than the first change amount determination threshold ΔTh_th1. it can. Therefore, when the filtering time for filtering spike noise is set long, it is possible to suppress the actual temperature of the switching element 41 from exceeding the upper limit of the normal operating temperature range of the switching element 41 during the filtering time. .

When the semiconductor device 11 is cooled by the cooling device 30, the control device 12 has the change amount ΔTh of the detected temperature Th calculated by the change amount calculation unit 52d smaller than the first change amount determination threshold value ΔTh_th1, and A third determination unit 52g is further provided that determines that the cooling device 30 is in failure when it is greater than the second change amount determination threshold value ΔTh_th2, which is set to a value smaller than the first change amount determination threshold value ΔTh_th1.
According to this, the failure of the cooling device 30 of the semiconductor device 11 can be determined by the third determination unit 52g. As a result, the state relating to the semiconductor device 11 can be determined more accurately.

In the control device 12, the change amount ΔTh of the detected temperature Th calculated by the change amount calculation unit 52d is larger than the temperature increase amount that the temperature of the switching element 41 rises during the control cycle time TM when the switching element 41 is operated. The temperature-sensitive diode 42 is abnormal when the value is larger than the first change amount determination threshold ΔTh_th1 set to the value and the acquired value acquired by the acquisition unit 51b is smaller than the acquired value determination threshold. A fourth determination unit 52h for determination is further provided.
According to this, the fourth determination unit 52h is acquired by the acquisition unit 51b even when the change amount ΔTh of the detected temperature Th calculated by the change amount calculation unit 52d is larger than the first change amount determination threshold value ΔTh_th1. It can be determined that the acquired value is not an external noise but an actual acquired value, and consequently, the temperature-sensitive diode 42 can be determined to be abnormal. As a result, the control device 12 can further suppress erroneous determination of the semiconductor device state.

The control device 12 includes a driving driver 51 for the switching element 41 and a CPU 52 for controlling the driving driver 51, and the second determination unit 52f determines that the switching element 41 is overheated by the first determination unit 52e. When the detected temperature Th calculated by the voltage-temperature converter 51c is greater than the detected temperature determination threshold Th_th after a predetermined time has elapsed from the time when it is determined to be an erroneous determination, between the driver 51 for driving and the CPU 52 Is further provided with a fifth determination unit 52i that determines that the electric wire 61 that connects is abnormal.
According to this, abnormality of the electric wire 61 which connects between the driver 51 for a drive and CPU52 can be determined by the 5th determination part 52i. As a result, the state relating to the semiconductor device 11 can be determined more accurately.

  In the above-described embodiment, the inverter device 10 is applied to a hybrid vehicle. However, instead of this, the inverter device 10 may be applied to a motor that drives a compressor of an air conditioner.

  DESCRIPTION OF SYMBOLS 12 ... Control apparatus (semiconductor device state determination apparatus), 20 ... Motor (control object), 41 ... Switching element, 42 ... Temperature sensitive diode, 11 ... Semiconductor device, 51b ... Acquisition part, 51c ... Voltage-temperature conversion part (detection) (Temperature calculation unit), 52 ... CPU, 52d ... change amount calculation unit, 52e ... first determination unit, 52f ... second determination unit, 30 ... cooling device, 52g ... third determination unit, 52h ... fourth determination unit, 61 ... Electric wire, 52i ... Fifth determination unit.

Claims (4)

A semiconductor device comprising: a plurality of switching elements that switch energization / non-energization to a controlled object; and a plurality of temperature-sensitive diodes that are adjacent to each switching element and detect the temperature of each switching element A semiconductor device state determination apparatus for determining a state,
An acquisition unit that acquires a forward voltage of each temperature-sensitive diode according to the temperature of each switching element;
A detection temperature calculation unit that calculates a detection temperature of the switching element corresponding to the acquisition value for each control cycle time from the acquisition value acquired by the acquisition unit;
From the acquired value acquired by the acquiring unit, a change amount calculating unit that calculates a change amount of the detected temperature of the switching element corresponding to the change amount of the acquired value for each control cycle time;
A first determination unit that determines that the switching element is in an overheated state when the detected temperature calculated by the detected temperature calculation unit is greater than a detection temperature determination threshold;
The detected temperature calculated by the detected temperature calculating unit is larger than a detected temperature determination threshold value, and the change amount of the detected temperature calculated by the change amount calculating unit is determined when the switching element is activated. When the temperature is greater than a first change amount determination threshold set to a value greater than the temperature increase amount that rises during the control cycle time, the first determination unit determines that the switching element is in an overheated state And a second determination unit that determines that is an erroneous determination. In the case where the semiconductor device is cooled by a cooling device,
In the semiconductor device state determination device, the change amount of the detected temperature calculated by the change amount calculation unit is set to a value smaller than the first change amount determination threshold and smaller than the first change amount determination threshold. The semiconductor device state determination apparatus according to claim 1, further comprising a third determination unit that determines that the cooling device is faulty when the second change amount determination threshold is greater than the second change amount determination threshold.   The change amount of the detected temperature calculated by the change amount calculation unit is set to a value larger than the temperature increase amount at which the temperature of the switching element rises during the control cycle time when the switching element is operated. Fourth determination for determining that the temperature-sensitive diode is abnormal when the threshold value is greater than the first change amount determination threshold value and the acquired value acquired by the acquisition unit is smaller than the acquired value determination threshold value. The semiconductor device state determination apparatus according to claim 1, further comprising a unit. The semiconductor device state determination apparatus includes a driver for driving the switching element and a CPU for controlling the driver for driving,
Calculated by the detected temperature calculation unit after a predetermined time has elapsed from the time when the determination by the second determination unit that the switching element is overheated by the first determination unit is an erroneous determination. 5. The fifth determination unit according to claim 1, further comprising: a fifth determination unit that determines that an electric wire connecting between the driver for driving and the CPU is abnormal when the detected temperature is greater than the detected temperature determination threshold. The semiconductor device state determination apparatus according to any one of claims 3 to 4.

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