JP6299368B2 - Semiconductor device temperature estimation device - Google Patents

Description

  The present invention relates to a temperature estimation technique for a semiconductor element provided in an inverter.

  Generally, since a heat is generated when a current flows through a semiconductor element provided in the inverter, the inverter is provided with a cooling device. The cooling device cools the semiconductor element by flowing a coolant such as cooling water through a flow path provided in the inverter, for example.

  Here, if an abnormality occurs in the cooling device, such as leakage of the refrigerant or stopping of the flow of the refrigerant, the cooling efficiency deteriorates. Therefore, when the cooling device is abnormal, it is necessary to perform temperature protection control by detecting or estimating the temperature of the semiconductor element so that the temperature of the semiconductor element is within the usable temperature range.

  Patent Document 1 discloses a method for estimating the temperature of a semiconductor element of an inverter based on a current flowing in a motor coil.

JP 2009-17707 A

  However, when the cooling device is normal, the temperature of the semiconductor element of the inverter can be accurately estimated based on the current flowing through the coil. However, when an abnormality occurs in the cooling device, the thermal resistance from the semiconductor element to the refrigerant changes. Therefore, an error occurs in the temperature estimation of the semiconductor element.

  An object of the present invention is to provide a technique for accurately estimating the temperature of a semiconductor element provided in an inverter when an abnormality occurs in a cooling device for cooling the inverter.

A semiconductor element temperature estimation apparatus according to the present invention is an apparatus for estimating the temperature of a semiconductor element provided in an inverter, and is provided in the inverter, and is provided with a temperature detection means for detecting the ambient temperature, and an inverter by flowing a refrigerant. An abnormality determining means for determining whether an abnormality has occurred in the cooling device for cooling the semiconductor device, and a temperature estimating means for estimating the temperature of the semiconductor element. If the temperature estimation means determines that an abnormality has occurred in the cooling device, the temperature rise in the inverter caused by the abnormality in the cooling device and the temperature rise due to the loss of the semiconductor element when no abnormality has occurred in the cooling device , And the temperature of the semiconductor element is estimated based on the calculated rising temperature inside the inverter, the calculated rising temperature due to the loss of the semiconductor element, and the temperature detected by the temperature detecting means.

  According to the present invention, when it is determined that an abnormality has occurred in the cooling device of the inverter, the temperature rises inside the inverter caused by the abnormality of the cooling device and the loss of the semiconductor element when no abnormality occurs in the cooling device. The temperature of the semiconductor element is estimated based on the rising temperature that is detected and the temperature detected by the temperature detecting means provided in the inverter, so even if the thermal resistance from the semiconductor element to the cooling device changes due to an abnormality in the cooling device. The temperature of the semiconductor element can be accurately estimated.

FIG. 1 is a diagram illustrating an inverter to which a semiconductor element temperature estimation apparatus according to an embodiment is applied and peripheral devices thereof. FIG. 2 is a flowchart showing a flow of control performed by the semiconductor element temperature estimation device in one embodiment. FIG. 3 is a diagram illustrating a time chart for determining the presence or absence of an abnormality occurring in the cooling device based on the estimated output value of the temperature sensor and the actual output value. FIG. 4 is a diagram illustrating a time chart in the case of determining whether there is an abnormality occurring in the cooling device based on the detection value of the temperature sensor and the detection value of the water temperature sensor. FIG. 5 is a diagram illustrating an example of a thermal resistance model from the semiconductor element to the refrigerant when the cooling device is normal. FIG. 6 is a diagram illustrating an example of a thermal resistance model used in the semiconductor element temperature estimation method when the cooling device is abnormal. FIG. 7 is a diagram illustrating a temperature change amount of a semiconductor element when an abnormality occurs in the cooling device and the loss of the semiconductor element is constant. FIG. 8 is a diagram illustrating a thermal resistance model including a thermal resistance component and a heat capacity component when an abnormality occurs in the cooling device. In FIG. 9, when it is determined that the cooling device is normal at the time of the previous calculation and an abnormality has occurred in the cooling device at the time of the current calculation, the base temperature of the semiconductor element is set by the same method as when the cooling device is normal. It is a flowchart which shows the flow of the process to calculate. FIG. 10 is a diagram illustrating a temperature change amount of a semiconductor element when an abnormality occurs in the cooling device and the semiconductor loss changes.

  FIG. 1 is a diagram illustrating an inverter to which a semiconductor element temperature estimation apparatus according to an embodiment is applied and peripheral devices thereof. This semiconductor element temperature estimation device is mounted and used, for example, in an electric vehicle, a hybrid vehicle, or a fuel cell vehicle that uses a three-phase AC motor 17 as a drive source. However, the application destination of the semiconductor element temperature estimation device is not limited to the vehicle, and can be applied to a system other than the vehicle.

  The inverter 1 converts the DC power of the battery 10 into AC power and supplies it to the three-phase AC motor 17. The inverter 1 is provided with a plurality of semiconductor elements (for example, IGBTs) 2 functioning as switching elements, and diodes connected in antiparallel with the semiconductor elements 2. More specifically, three pairs of two semiconductor elements 2 connected in series are provided.

  The inverter 1 is provided with a refrigerant flow path for flowing a refrigerant such as cooling water. The pump 19 is driven to feed the refrigerant into the refrigerant flow path, thereby depriving the semiconductor element 2 of the inverter 1 of heat. The refrigerant warmed by the heat of the semiconductor element 2 is cooled by releasing heat when passing through the radiator 11. The cooled refrigerant is sent again to the refrigerant flow path provided in the inverter 1.

  The water temperature sensor 18 detects the temperature of the refrigerant flowing in the refrigerant flow path.

  The temperature sensor 13 is provided inside the inverter 1 at a position physically separated from the semiconductor element 2 and detects the ambient temperature. In FIG. 1, three temperature sensors 13 are provided corresponding to the upper semiconductor element 2 among the two semiconductor elements 2 connected in series.

  The three current sensors 14 detect U-phase, V-phase, and W-phase currents flowing from the inverter 1 to the three-phase AC motor 17.

  The rotation sensor 16 is, for example, a resolver or an encoder, and detects the rotor phase of the three-phase AC motor 17.

  The control circuit 15 controls on / off of the semiconductor element 2 provided in the inverter 1 and inputs detection values of the temperature sensor 13, the current sensor 14, and the water temperature sensor 18, and the temperature of the semiconductor element 2. , And temperature protection control of the semiconductor element 2 is performed based on the estimated temperature.

  FIG. 2 is a flowchart showing a flow of control performed by the semiconductor element temperature estimation device in one embodiment. The process starting from step S1 is performed by the control circuit 15.

  In step S1, it is determined whether an abnormality has occurred in the cooling device. The cooling device is a device that cools the semiconductor element 2 by flowing a refrigerant through a refrigerant flow path provided in the inverter 1.

  The abnormality of the cooling device is, for example, by estimating the output of the temperature sensor 13 based on the thermal resistance model from the temperature sensor 13 to the refrigerant and the loss of the semiconductor element 2, and the estimated output value of the temperature sensor 13 and the actual output When the difference between the two values is equal to or greater than a predetermined threshold Th1, it is determined that an abnormality has occurred in the cooling device. The thermal resistance model from the temperature sensor 13 to the refrigerant and the loss of the semiconductor element 2 can be obtained in advance.

  FIG. 3 is a diagram showing a time chart in the case of determining whether there is an abnormality occurring in the cooling device based on the estimated output value of the temperature sensor 13 and the actual output value. In FIG. 3, the temperature sensor value, the loss of the semiconductor element 2, and the cooling device abnormality determination flag are shown in order from the top. The temperature sensor value includes a detected value and an estimated value of the temperature sensor 13. The cooling device abnormality determination flag is a flag indicating 0 when the cooling device is normal and 1 when the cooling device is abnormal.

  In FIG. 3, at time T30, the difference between the detected value of the temperature sensor 13 and the estimated value becomes equal to or greater than a predetermined threshold Th1, and it is determined that an abnormality has occurred in the cooling device, and the cooling device abnormality determination flag changes from 0 to 1. doing.

  The abnormality of the cooling device can also be determined based on the detection value of the temperature sensor 13 and the detection value of the water temperature sensor 18. That is, when the difference between the detection value of the temperature sensor 13 and the detection value of the water temperature sensor 18 is equal to or greater than the predetermined threshold Th2, it is determined that an abnormality has occurred in the cooling device.

  FIG. 4 is a diagram illustrating a time chart in the case of determining whether there is an abnormality occurring in the cooling device based on the detection value of the temperature sensor 13 and the detection value of the water temperature sensor 18. In FIG. 4, the difference between the detection values of the temperature sensor 13 and the water temperature sensor 18, the loss of the semiconductor element 2, and the cooling device abnormality determination flag are shown in order from the top. As in FIG. 3, the cooling device abnormality determination flag is a flag indicating 0 when the cooling device is normal and 1 when the cooling device is abnormal.

  In FIG. 4, at time T40, the difference between the detection value of the temperature sensor 13 and the detection value of the water temperature sensor 18 is equal to or greater than a predetermined threshold Th2, and it is determined that an abnormality has occurred in the cooling device, and the cooling device abnormality determination flag is 0. It has changed from 1 to 1.

  If it is determined in step S1 of FIG. 2 that an abnormality has occurred in the cooling device, the process proceeds to step S2, based on the thermal resistance between the semiconductor element 2 and the refrigerant, the loss of the semiconductor element 2, and the detected value of the temperature sensor 13. Thus, the temperature Tj of the semiconductor element 2 is estimated. On the other hand, if it is determined that there is no abnormality in the cooling device, the process proceeds to step S3, where the semiconductor element is based on the thermal resistance between the semiconductor element 2 and the refrigerant, the loss of the semiconductor element 2, and the detected value of the water temperature sensor 18. 2 temperature Tj is estimated.

  First, the process of step S3, that is, the temperature estimation method of the semiconductor element 2 when the cooling device is normal will be described. When the cooling device is normal, the temperature Tj of the semiconductor element 2 is estimated based on the thermal resistance model from the semiconductor element 2 to the refrigerant, the loss of the semiconductor element 2, and the detected value of the water temperature sensor 18.

  FIG. 5 is a diagram illustrating an example of a thermal resistance model from the semiconductor element 2 to the refrigerant when the cooling device is normal. In FIG. 5, the circuit of the thermal resistance model is shown superimposed on the diagram showing the structure of the inverter 1.

  The semiconductor element 2 is fixed on the ceramic substrate 51 via the solder 53. A copper foil 52 is provided between the ceramic substrate 51 and the solder 53.

  The temperature sensor 13 is provided at a position physically separated from the semiconductor element 2. The temperature sensor 13 is fixed on the ceramic substrate 51 via the solder 53.

  A cooler 54 is provided below the ceramic substrate 51. More specifically, the cooler 54 is soldered to the ceramic substrate 51 with solder 53, and a copper foil 52 is provided between the solder 53 and the ceramic substrate 51.

  The cooler 54 is provided with a refrigerant flow path 55 for flowing a refrigerant, and a flow path cover 56 is provided outside the refrigerant flow path 55.

  In the present embodiment, a model in which a plurality of thermal resistance components and thermal capacity components are connected is considered as a thermal resistance model from the semiconductor element 2 to the refrigerant flowing through the refrigerant flow path 55. Here, as shown in FIG. 5, description will be made assuming that the thermal resistance components are three of R1 to R3 and the heat capacity components are three of C1 to C3.

The temperature Tj of the semiconductor element 2 can be estimated from the following equation (1). However, since the calculation of Expression (1) is repeatedly performed, the estimated temperature Tj of the semiconductor element 2 at the time of the s-th calculation is represented as Tj (s). Further, T _B (s) in equation (1) is the base temperature of the semiconductor element 2 at the time of the s-th calculation, and ΔT _j (s) is the temperature due to the loss of the semiconductor element 2 at the time of the s-th calculation. It is an increase and can be calculated by equation (2). N in the formula (2) is the number of heat resistance components and heat capacity components, and n is 3 when there are three heat resistance components and heat capacity components as shown in FIG. The base temperature T _B (s) of the semiconductor element 2 is the detected temperature Tw of the water temperature sensor 18 at the time of the s-th calculation.

In Expression (2), ΔT _i (s) represents the temperature rise of the semiconductor element 2 due to the i-th thermal resistance component and heat capacity component at the time of the s-th calculation, and is represented by the following Expression (3).

In Expression (3), Δt represents the time elapsed between the (s−1) th and sth calculations. P _(s-1) is the loss of the semiconductor element 2 at the (s-1) th calculation, Rth _i is the i-th thermal resistance component, and τ _i is the i-th thermal resistance component and the heat capacity component. Represents the product of

  The thermal resistance component and the heat capacity component in FIG. 5 can be experimentally obtained in advance under certain conditions. Further, the loss of the semiconductor loss 2 can be obtained in advance.

Therefore, the temperature rise ΔT _i (s) of the semiconductor element 2 due to the i (i = 1 to 3) th thermal resistance component / heat capacity component at the time of the s-th calculation is obtained from Equation (3), and from Equation (2). By adding the obtained temperature rise ΔT _i (s) of the semiconductor element 2 due to the first to third thermal resistance components and heat capacity components, the temperature rise ΔT _j (s ) Is calculated. Then, by adding the temperature rise ΔT _j (s) to the base temperature T _B (s) of the semiconductor element 2 at the time of the s-th calculation, the temperature Tj (s) of the semiconductor element 2 at the time of the s-th calculation is obtained. Ask.

Next, the process of step S2 in FIG. 2, that is, the temperature estimation method of the semiconductor element 2 when the cooling device is abnormal will be described. Even when an abnormality occurs in the cooling device, the temperature Tj of the semiconductor element 2 is estimated by the equation (1). However, when an abnormality occurs in the cooling device, the base temperature of the semiconductor element 2 increases, and therefore, the base temperature T _B (s) of the semiconductor element 2 is taken into account in consideration of the temperature increase of the semiconductor element 2. Is calculated. That is, the temperature increase ΔT _j (s) due to the loss of the semiconductor element 2 when the cooling device is normal is added to the base temperature T _B (s) of the semiconductor element 2 when the cooling device is abnormal. The temperature Tj of the semiconductor element 2 is estimated by adding (see). An example of the thermal resistance model in this case is shown in FIG.

When abnormality has occurred in the cooling device, the base temperature T _B (s) of the semiconductor element 2 is calculated by the following equation (4). However, in Expression (4), ΔTj ′ (s) is the temperature rise inside the inverter at the time of the s-th calculation, and Ts (s) is the detected temperature of the temperature sensor 13 at the time of the s-th calculation. .

  The temperature rise ΔTj ′ (s) inside the inverter at the time of the sth calculation is calculated by the following equation (5).

In Formula (5), Rth ′ _i represents the i-th thermal resistance component when abnormality occurs in the cooling device, and τ ′ _i represents the i-th thermal resistance component when abnormality occurs in the cooling device. It represents the product of heat capacity components. Rth ′ _i and τ ′ _i are obtained in advance from the difference in temperature change of the semiconductor element 2 when the loss is the same when the cooling device is normal and when it is abnormal (when there is no refrigerant).

  FIG. 7 is a diagram illustrating a temperature change amount of the semiconductor element 2 when an abnormality occurs in the cooling device and the loss of the semiconductor element 2 is constant. In FIG. 7, the temperature change amount of the semiconductor element 2, the detected temperature of the temperature sensor 13, the loss of the semiconductor element 2, and the torque of the three-phase AC motor 17 are shown in order from the top. The temperature change amount of the semiconductor element 2 was calculated from the detected value of the temperature sensor 13 with a dotted line, and the temperature change amount calculated from the loss of the semiconductor element 2 with a dashed line. A solid line represents the temperature change amount of the semiconductor element 2 estimated based on the temperature change amount calculated from the temperature change amount and the loss of the semiconductor element 2.

  When the temperature sensor 13 is disposed at a position physically separated from the semiconductor element 2 when a temperature change occurs due to a sudden change in the heat generation amount of the semiconductor element 2, as shown in FIG. Since the temperature change amount calculated from the detected value differs greatly from the actual temperature change amount of the semiconductor element 2, the temperature protection control of the semiconductor element 2 cannot be appropriately performed based on the detected value of the temperature sensor 13. However, in the present embodiment, the temperature of the semiconductor element 2 is estimated based on the thermal resistance between the semiconductor element 2 and the refrigerant, the loss of the semiconductor element 2, and the detected value of the temperature sensor 13. Can be accurately estimated, and temperature protection control of the semiconductor element 2 can be appropriately performed.

  The temperature Tj of the semiconductor element 2 can also be estimated by a method different from the method described above. For example, the thermal resistance component that has changed due to the abnormality of the cooling device can be estimated based on the detected value of the temperature sensor 13, and the temperature Tj of the semiconductor element 2 can be estimated based on the estimated thermal resistance component. FIG. 8 is a diagram showing a thermal resistance model including thermal resistance components R1 'to R3' and thermal capacity components C1 'to C3' when abnormality occurs in the cooling device.

  Returning to the flowchart of FIG. In step S4, it is determined whether or not the temperature Tj of the semiconductor element 2 estimated in step S2 or step S3 exceeds a predetermined protection temperature. If it is determined that the estimated temperature Tj of the semiconductor element 2 does not exceed the predetermined protection temperature, the process returns to step S1, and if it is determined that the estimated temperature Tj exceeds the predetermined protection temperature, the process proceeds to step S5.

  In step S5, for example, the output of the inverter 1 is limited, the output is stopped, and the like, thereby performing protection control of the semiconductor element 2 and reducing the temperature of the semiconductor element 2.

In the flowchart shown in FIG. 2, when it is determined that an abnormality has occurred in the cooling device, the base temperature T _B (s) of the semiconductor element 2 is calculated by a method different from that when the cooling device is normal. However, a normal cooling device in the previous calculation, if it is determined that an abnormality has occurred in this cooling device during operation, by the same manner as the cooling device is normal, the semiconductor element 2 base temperature T _B (S) may be calculated.

FIG. 9 shows that the base temperature of the semiconductor element 2 is determined by the same method as when the cooling device is normal when it is determined that the cooling device is normal at the previous calculation and the cooling device has an abnormality at the current calculation. it is a flowchart showing a flow of a process for calculating the T _B (s). Steps for performing the same processing as in the flowchart shown in FIG. 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

  If it is determined in step S1 that an abnormality has occurred in the cooling device, the process proceeds to step S11. In step S11, it is determined whether or not the cooling device was normal at the previous calculation. If it is determined that the cooling device is normal at the previous calculation, the process proceeds to step S12.

In step S12, the detected temperature Tw of the water temperature sensor 18 is set as the base temperature T _B (s) of the semiconductor element 2, and the temperature Tj of the semiconductor element 2 is estimated. The only difference from the process of step S2 in FIG. 2 is the base temperature T _B (s) of the semiconductor element 2, and the estimation method of the temperature Tj of the semiconductor element 2 is the same.

  On the other hand, if it is determined in step S11 that the cooling device is not normal during the previous calculation, the process proceeds to step S2.

  As described above, according to the semiconductor element temperature estimation device in the embodiment, it is determined whether or not an abnormality has occurred in the cooling device for cooling the inverter 1. The generated rising temperature inside the inverter 1 and the rising temperature caused by the loss of the semiconductor element 2 when no abnormality has occurred in the cooling device are calculated, and the calculated rising temperature inside the inverter 1 and the semiconductor element 2 The temperature of the semiconductor element 2 is estimated based on the rising temperature resulting from the loss and the temperature around the semiconductor element 2 detected by the temperature sensor 13. As a result, even when an abnormality occurs in the cooling device and the thermal resistance from the semiconductor element 2 to the refrigerant changes, the temperature of the semiconductor element 2 can be accurately estimated in consideration of the change in thermal resistance. .

  Here, a method is conceivable in which a thermal resistance model is prepared in advance when an abnormality occurs in the cooling device, and the temperature of the semiconductor element 2 is estimated using this thermal resistance model. However, since there are various abnormal states such as a state where the refrigerant is flowing little by little, a state where the refrigerant is completely stopped, a state where there is no refrigerant, etc., there is a thermal resistance corresponding to each abnormal state. Although a model is required, it is impossible to prepare a thermal resistance model corresponding to all abnormal states in advance.

  In addition, when the temperature detection value of the temperature sensor provided in the inverter exceeds a predetermined threshold value, it is possible to determine that a cooling device abnormality or a semiconductor element temperature abnormality has occurred, and to perform protection control of the semiconductor element. In this method, when the temperature sensor is provided in the immediate vicinity of the semiconductor element, the temperature of the semiconductor element can be detected with relatively high accuracy by the temperature sensor, so that the protection control of the semiconductor element can be performed. However, when the temperature sensor is provided at a position physically separated from the semiconductor element, the temperature detection value of the temperature sensor is different from the temperature of the semiconductor element. When the accompanying temperature change or the like occurs, the semiconductor device protection control cannot be appropriately performed by the above-described method.

  FIG. 10 is a diagram illustrating a temperature change amount of the semiconductor element 2 when the loss of the semiconductor is changed due to an abnormality in the cooling device. 10, the temperature change amount of the semiconductor element 2, the temperature detected by the temperature sensor 13, the loss of the semiconductor element 2, and the torque of the three-phase AC motor 17 are shown in order from the top. The temperature change amount of the semiconductor element 2 is the temperature change amount calculated from the detection value of the temperature sensor 13 with a dotted line, and the temperature change amount calculated from the loss of the semiconductor element 2 is a dashed line. The temperature change amount of the semiconductor element 2 estimated from the loss of 2 is represented by a solid line. As shown in FIG. 10, the temperature change amount (dotted line) calculated from the detected value of the temperature sensor 13 is estimated from the detected value of the temperature sensor 13 and the loss of the semiconductor element 2, particularly after the loss of the semiconductor element 2 has changed. This is very different from the amount of temperature change (solid line). Therefore, when the detection value of the temperature sensor exceeds a predetermined threshold value, the method for determining that the cooling device abnormality or the semiconductor element temperature abnormality has occurred delays the timing of starting the protection control of the semiconductor element, and appropriately detects the semiconductor element. Protection cannot be performed. However, according to the semiconductor element temperature estimation device in one embodiment, when it is determined that an abnormality has occurred in the cooling device, an internal temperature rise of the inverter 1 caused by the abnormality in the cooling device and an abnormality has occurred in the cooling device. When the temperature rises due to the loss of the semiconductor element 2 in the case where there is not, the calculated rise temperature inside the inverter 1, the calculated rise temperature due to the loss of the semiconductor element 2, and the temperature detected by the temperature sensor 13 Therefore, the temperature of the semiconductor element 2 is accurately estimated even when a temperature change caused by a sudden change in the heat generation amount of the semiconductor element 2 as shown in FIG. 10 occurs. Therefore, protection control of the semiconductor element 2 can be appropriately performed.

  Further, according to the semiconductor element temperature estimation device in one embodiment, when it is determined that no abnormality has occurred in the cooling device, the temperature of the refrigerant detected by the water temperature sensor 18 and no abnormality has occurred in the cooling device. The temperature of the semiconductor element is estimated based on the temperature rise due to the loss of the semiconductor element 2 in the case. Thereby, when no abnormality has occurred in the cooling device, the temperature of the semiconductor element 2 can be estimated with high accuracy, so that the protection control of the semiconductor element 2 can be appropriately performed.

  Further, the output value of the temperature sensor 13 is estimated based on the relationship between the thermal resistance model from the temperature sensor 13 to the refrigerant and the loss of the semiconductor element 2 when there is no abnormality in the cooling device, and the estimated temperature sensor Based on the difference between the output value of 13 and the detection value of the temperature sensor 13, it is determined whether or not an abnormality has occurred in the cooling device. Accordingly, it is possible to accurately determine whether or not an abnormality has occurred in the cooling device, and therefore, it is possible to appropriately estimate the temperature of the semiconductor element 2 using a temperature estimation method according to the presence or absence of an abnormality in the cooling device. Can do.

  Furthermore, based on the difference between the temperature detected by the temperature sensor 13 and the temperature detected by the water temperature sensor 18, it can be determined whether or not an abnormality has occurred in the cooling device. In this case as well, it is possible to accurately determine whether or not an abnormality has occurred in the cooling device. Therefore, it is possible to appropriately estimate the temperature of the semiconductor element 2 using a temperature estimation method according to the presence or absence of an abnormality in the cooling device. Can do.

  The present invention is not limited to the embodiment described above.

DESCRIPTION OF SYMBOLS 1 ... Inverter 2 ... Semiconductor element 13 ... Temperature sensor (temperature detection means)
15 ... Control circuit (abnormality determination means, temperature estimation means, output estimation means)
18 ... Water temperature sensor (refrigerant temperature detection means)
54 ... Cooler

Claims (4)

A semiconductor element temperature estimation device for estimating a temperature of a semiconductor element provided in an inverter,
A temperature detecting means provided in the inverter for detecting the ambient temperature;
An abnormality determining means for determining whether an abnormality has occurred in the cooling device that cools the inverter by flowing a refrigerant ;
Temperature estimation means for estimating the temperature of the semiconductor element;
With
When the temperature estimation means determines that an abnormality has occurred in the cooling device, the temperature rise inside the inverter caused by the abnormality of the cooling device and the semiconductor element in the case where no abnormality has occurred in the cooling device Calculate the rising temperature caused by the loss, based on the calculated rising temperature inside the inverter, the calculated rising temperature caused by the loss of the semiconductor element, and the temperature detected by the temperature detecting means, Estimating the temperature of the semiconductor element,
A semiconductor device temperature estimation device. In the semiconductor element temperature estimation apparatus according to claim 1,
Further comprising a refrigerant temperature detecting means for detecting the temperature of the pre-Symbol refrigerant,
It said temperature estimation means, said an abnormality in the cooling device is determined not to have occurred, and the temperature of the refrigerant detected by the refrigerant temperature detecting means, said semiconductor device when the abnormality in the cooling device does not occur Estimating the temperature of the semiconductor element based on the rising temperature resulting from the loss of
A semiconductor device temperature estimation device. In the semiconductor element temperature estimation apparatus according to claim 2,
Output estimation means for estimating the output value of the temperature detection means based on the relationship between the thermal resistance model from the temperature detection means to the refrigerant and the loss of the semiconductor element when no abnormality has occurred in the cooling device Further comprising
The abnormality determination unit determines whether an abnormality has occurred in the cooling device based on a difference between an output value of the temperature detection unit estimated by the output estimation unit and a detection value of the temperature detection unit. To
A semiconductor device temperature estimation device. In the semiconductor element temperature estimation apparatus according to claim 2,
The abnormality determining means determines whether an abnormality has occurred in the cooling device based on a difference between the temperature detected by the temperature detecting means and the temperature detected by the refrigerant temperature detecting means;
A semiconductor device temperature estimation device.

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