Inverter control device

Abstract

This inverter control device comprises: a plurality of temperature-sensing elements providing corresponding to a plurality of switching elements; a temperature detection circuit that receives detection signals from the temperature-sensing elements and outputs temperature detection information; a control unit that calculates the temperature of the switching elements on the basis of the temperature detection information; and a switching circuit that switches the detection signals from the plurality of temperature-sensing elements and outputs the detection signals to the temperature detection circuit, the control unit operating the switching circuit to select the detection signal to be output from the temperature-sensing element to the temperature detection circuit.

Description

Technical Field

[0001] The present invention relates to an inverter control device.

Background Art

[0002] For temperature detection using a temperature-sensitive element such as a temperature-sensitive diode, a temperature detection circuit that outputs a detection signal detected by the temperature-sensitive element to a control unit such as a microcomputer is provided. For example, in an inverter, the temperature-sensitive element is installed on the high-voltage side, and a control unit such as a microcomputer that monitors temperature detection information is installed on the low-voltage side. A plurality of temperature detection circuits including a circuit that separates the two with an insulating element are provided corresponding to a plurality of temperature-sensitive elements.

[0003] In Patent Document 1, a temperature-sensitive diode for detecting the temperature of a switching element of an inverter is provided, and a temperature detection circuit composed of a voltage detection circuit, a pulse signal output circuit, a photocoupler, etc. is provided corresponding to each of the temperature-sensitive diodes.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the device described in Patent Document 1, a plurality of temperature detection circuits are required corresponding to a plurality of temperature-sensitive elements, and the configuration of the inverter control device has become complicated.

Means for Solving the Problems

[0006] The inverter control device according to the present invention is provided corresponding to a plurality of switching elements connected to the current path to which current is supplied.A plurality of temperature sensing elements, a temperature detection circuit that receives detection signals from the temperature sensing elements and outputs temperature detection information, and a control unit that calculates the temperature of the switching element based on the temperature detection information, The device has multiple temperature-sensing elements and multiple switching elements connected in parallel to each of them, and by turning each of the multiple switching elements on or off, the supply state of the current from the current path to the multiple temperature-sensing elements is switched. The control unit comprises a switching circuit, By controlling the on / off state of each of the multiple switching elements to switch the current path, multiple Select the detection signal to be output from the temperature sensing element to the temperature detection circuit. Each of the plurality of switching elements is sealed to each phase of the three-phase power module, and supplies the potential of the power module corresponding to the switched-off switching element as the potential of the ground side of the current path. . [Effects of the Invention]

[0007] According to the present invention, the configuration of the inverter control device can be simplified. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a circuit diagram of the inverter control device in the first embodiment. [Figure 2] Figures 2(a) to 2(f) are timing charts showing the first switching of the temperature sensing element. [Figure 3] Figures 3(a) to 3(f) are timing charts showing the second switching of the temperature sensing element. [Figure 4] Figure 4 is a circuit diagram of the inverter control device in the second embodiment. [Figure 5] Figures 5(a) to 5(e) are timing charts showing the switching of the temperature sensing element in the second embodiment. [Figure 6] Figure 6 is a circuit diagram of the inverter control device in the third embodiment. [Figure 7] Figures 7(a) to 7(h) are timing charts showing the switching of the ground potential supply element in the third embodiment.

[0009] Embodiments of the present invention will be described below with reference to the drawings. The following description and drawings are illustrative for illustrating the present invention, and have been omitted and simplified as appropriate for clarity of explanation. The present invention can also be carried out in various other forms. Unless otherwise specified, each component may be singular or plural.

[0010] The positions, sizes, shapes, and ranges of the components shown in the drawings may not represent their actual positions, sizes, shapes, and ranges in order to facilitate understanding of the invention. Therefore, the present invention is not necessarily limited to the positions, sizes, shapes, and ranges disclosed in the drawings.

[0011] [First Embodiment] Figure 1 is a circuit diagram of the inverter control device 100 in the first embodiment of the present invention.

[0012] The inverter control device 100 is connected to the power module 200 and controls the drive of the power module 200. The Power Module 200 consists of U-phase Power Module 200U, V-phase Power Module 200V, and W-phase Power Module 200W.

[0013] The U-phase power module 200U is equipped with switching elements 200E corresponding to the upper arm and lower arm, respectively. Each switching element 200E consists of an IGBT 200I and a diode 200D. A temperature sensing element T1 is provided corresponding to the upper arm or lower arm switching element 200E. The U-phase power module 200U integrates the upper arm switching element 200E, the lower arm switching element 200E, and the temperature sensing element T1 into a single package and seals it with a resin material. Similarly, the V-phase power module 200V integrates the upper arm switching element 200E, the lower arm switching element 200E, and the temperature sensing element T2 into a single package. Similarly, the W-phase power module 200W integrates the upper arm switching element 200E, the lower arm switching element 200E, and the temperature sensing element T3 into a single package.

[0014] Note that the switching element 200E is a power semiconductor device such as a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) in addition to an IGBT (Insulated Gate Bipolar Transistor), and the diode 200D is provided as needed. The power module 200 will be described by taking a 2in1 structure in which two of the upper arm and the lower arm are integrated into one module as an example, but other structures such as a structure in which a plurality of upper arms and lower arms are integrated into one module may be used.

[0015] The U-phase power module 200U, the V-phase power module 200V, and the W-phase power module 200W are connected to a three-phase bridge circuit to form an inverter. By inputting a drive signal to the gate terminal of the IGBT 200I, the switching element 200E is turned on and off to convert the DC voltage input between the positive and negative sides of the power module 200 into AC power. The converted AC power is supplied to the windings of each phase of a motor (not shown) from the connection end of the upper arm and the lower arm to drive the motor.

[0016] The inverter control device 100 includes a control unit 110, a switching circuit 120, a temperature detection circuit 130, and a drive circuit 140.

[0017] The inverter control device 100 is electrically separated into a high voltage side HV and a low voltage side LV on a substrate. The high voltage side HV of the inverter control device 100 is connected to the power module 200 via a connection part 100C such as a connector. The control unit 110 is arranged on the low voltage side LV of the inverter control device 100. The switching circuit 120, the temperature detection circuit 130, and the drive circuit 140 are electrically separated into a high voltage side HV and a low voltage side LV inside, and their electrical signals are exchanged via an insulating element.

[0018] The control unit 110 is a microcomputer or a CPU (Central Processing Unit), and generates a drive signal for driving the power module 200 according to a torque command input from a higher-level control device (not shown). Also, the control unit 110 detects the temperature of the power module 200 in order to detect the state of the power module 200. When detecting the temperature, the control unit 110 outputs command signals DO1, DO2, and DO3 to a switching circuit 120 described later to operate the switching circuit 120 and select a detection signal output from temperature sensors T1, T2, and T3 to a temperature detection circuit 130 described later. Then, based on the temperature detection information input to the input terminal PI from the temperature detection circuit 130, the temperature of the switching element 200E is calculated.

[0019] The switching circuit 120 switches the detection signals from the temperature sensors T1, T2, and T3 to be detected according to the command signals DO1, DO2, and DO3. Specifically, according to the command signals DO1, DO2, and DO3, the detection signals from the temperature sensors T1, T2, and T3 are switched by switching the current path of the current supplied to the temperature sensors T1, T2, and T3 to be detected.

[0020] The command signals DO1, DO2, and DO3 output from the control unit 110 are respectively input to an insulating element 121A. The insulating element 121A is, for example, a photocoupler formed by sealing a light-emitting element and a light-receiving element in one package. The ground on the light-emitting element side is connected to the ground GND2 on the low voltage side LV, and the ground on the light-receiving element side is connected to the ground GND1 on the high voltage side HV. The voltage VCC1 on the high voltage side HV is supplied to the output lines L1, L2, and L3 to the switching elements S1, S2, and S3 on the light-receiving element side via a resistor 123C. The switching elements S1, S2, and S3 turn on when the voltage VCC1 is supplied to their gate sides and turn off when it is not supplied. Each of the switching elements S1, S2, and S3 is connected in parallel with each of the temperature sensors T1, T2, and T3 provided in each phase of the power module 200.

[0021] The temperature sensing elements T1, T2, and T3, provided in each phase of the power module 200, are connected in series to the current path. A constant current is supplied to one end of the series connection from terminal IN of the temperature detection circuit 130 via offset resistor R1. The other end of the series connection is connected to terminal GND of the temperature detection circuit 130 via offset resistor R2. Terminal GND is connected to the ground GND1 of the high voltage side HV.

[0022] The temperature detection circuit 130 detects the voltage between terminal IN and terminal GND as a detection signal from the temperature sensing elements T1, T2, and T3, converts the detected voltage into a duty cycle wave corresponding to that voltage, and outputs it to the control unit 110 as temperature detection information via the OUT terminal. The offset resistors R1 and R2 are used to adjust the voltage between terminal IN and terminal GND by providing an offset so that it falls within the input voltage specifications of the temperature detection circuit 130. The control unit 110 converts the duty cycle wave output from the temperature detection circuit 130 into a voltage and calculates the temperature by referring to the voltage-temperature characteristics of the temperature sensing elements T1, T2, and T3 that are stored internally in advance. Although the temperature detection circuit 130 is described as outputting a duty cycle wave as temperature detection information, it may also output other forms of information that the control unit 110 can decipher.

[0023] The drive circuit 140 drives the switching element 200E in the power module 200 on and off based on the drive signal from the control unit 110.

[0024] Figures 2(a) to 2(f) are timing charts showing the first switching of temperature sensing elements T1, T2, and T3. Figures 2(a) to 2(c) are timing charts for command signals DO1, DO2, and DO3, and Figures 2(d) to 2(f) are timing charts for switching elements S1, S2, and S3.

[0025] As shown in Figures 2(a) to 2(c), the control unit 110 outputs command signals DO1, DO2, and DO3 to sequentially select one of the temperature sensing elements T1, T2, and T3 of the U-phase power module 200U, V-phase power module 200V, and W-phase power module 200W. In response to these command signals DO1, DO2, and DO3, the switching circuit 120 operates, and the switching elements S1, S2, and S3 are turned on / off as shown in Figures 2(d) to 2(f).

[0026] For example, when switching element S1 is off and switching elements S2 and S3 are on, current is supplied only to the temperature sensing element T1 of the U-phase power module 200U. As a result, at this timing, the temperature sensing element T1 of the U-phase power module 200U is in operation. The temperature detection circuit 130 detects the voltage between terminal IN and terminal GND, i.e., (voltage of temperature sensing element T1 + voltage of offset resistor R1 + voltage of offset resistor R2), converts the detected voltage into a duty cycle corresponding to that voltage, and outputs it to the control unit 110 from the OUT terminal. The control unit 110 converts the duty cycle detected at this timing back into a voltage and calculates the temperature by referring to the voltage-temperature characteristics of the temperature sensing element T1. This temperature is used as the detected temperature of the U-phase power module 200U. Similarly, the temperature of the V-phase power module 200V is calculated when switching element S2 is off and switching elements S1 and S3 are on, and the temperature of the W-phase power module 200W is calculated when switching element S3 is off and switching elements S1 and S2 are on.

[0027] In this embodiment, the first switching of the temperature sensing elements T1, T2, and T3 allows the temperature of each phase of the power module 200 to be detected while switching the switching elements S1, S2, and S3. As a result, one temperature detection circuit 130 can detect the temperature of three phases, simplifying the configuration of the inverter control device 100 and reducing the cost of configuration compared to the case where three temperature detection circuits 130 are provided. Furthermore, when three temperature detection circuits 130 are provided, current flows constantly through the temperature sensing elements T1, T2, and T3. However, in this embodiment, the switching by the switching circuit 120 shortens the period during which current flows through the temperature sensing elements T1, T2, and T3 to one-third, thereby extending the lifespan of the temperature sensing elements T1, T2, and T3 and improving the reliability of the temperature sensing elements T1, T2, and T3, and consequently the reliability of temperature detection. Furthermore, if the temperature detection circuit 130 is provided for three phases, current is supplied to the temperature sensing elements T1, T2, and T3 for each phase. However, in this embodiment, the supplied current is used in common, so variations in current for each phase are eliminated, and the accuracy of temperature detection can be improved.

[0028] Figures 3(a) to 3(f) are timing charts showing the second switching of temperature sensing elements T1, T2, and T3. Figures 3(a) to 3(c) are timing charts for command signals DO1, DO2, and DO3, and Figures 3(d) to 3(f) are timing charts for switching elements S1, S2, and S3.

[0029] As shown in Figures 3(a) to 3(c), the control unit 110 outputs command signals DO1, DO2, and DO3 to sequentially select two phases of the temperature sensing elements T1, T2, and T3 of the U-phase power module 200U, V-phase power module 200V, and W-phase power module 200W. In response to these command signals DO1, DO2, and DO3, the switching circuit 120 operates, and the switching elements S1, S2, and S3 are turned on / off as shown in Figures 3(d) to 3(f).

[0030] For example, when selecting temperature sensing elements T1 and T2 for the U-phase power module 200U and the V-phase power module 200V, switching elements S1 and S2 are turned off, and switching element S3 is turned on. At this timing, current is supplied to the temperature sensing elements T1 and T2 of the U-phase power module 200U and the V-phase power module 200V, but no current is supplied to the temperature sensing element T3 of the W-phase power module 200W.

[0031] As a result, at this timing, the temperature detection circuit 130 detects the voltage between terminal IN and terminal GND, i.e., (voltages of series-connected temperature sensing elements T1 and T2 + voltage of offset resistor R1 + voltage of offset resistor R2). The detected voltage is then converted into a duty cycle corresponding to that voltage and output to the control unit 110 via the OUT terminal. The control unit 110 converts the duty cycle detected at this timing back into a voltage and calculates the temperature by referring to the voltage-temperature characteristics of temperature sensing elements T1 and T2. From this temperature, the average detected temperature of the U-phase power module 200U and the V-phase power module 200V is calculated. The average detected temperature of the V-phase power module 200V and the W-phase power module 200W, and the average detected temperature of the W-phase power module 200W and the U-phase power module 200U are calculated in the same manner.

[0032] The second switching of the temperature sensing elements T1, T2, and T3 in this embodiment simplifies the configuration of the inverter control device 100 and reduces configuration costs compared to the case where the temperature detection circuit 130 is provided for three phases, similar to the first switching method. Furthermore, the switching by the switching circuit 120 shortens the period during which current flows through the temperature sensing elements T1, T2, and T3 to two-thirds, thereby extending the lifespan of the temperature sensing elements T1, T2, and T3 and improving their reliability. In addition, since the supplied current is used in common, variations in current between phases are eliminated, improving the accuracy of temperature detection.

[0033] Next, we will explain an example of using a combination of the first and second switching modes of the temperature sensing elements T1, T2, and T3. In the following explanation, I is the current value supplied to the temperature sensing elements T1, T2, and T3, and R is the resistance value of the offset resistors R1 and R2.

[0034] In the first switching phase, if the voltage of the U-phase temperature sensing element T1 is Vf(U), the voltage of the V-phase temperature sensing element T2 is Vf(V), and the voltage of the W-phase temperature sensing element T3 is Vf(W), then the voltage between terminal IN and terminal GND of the temperature detection circuit 130 is expressed by the following equations (1), (2), and (3) for each phase. Vf(U)+2IR ···(1) Vf(V)+2IR ···(2) Vf(W)+2IR ···(3)

[0035] The temperature detection circuit 130 outputs duty cycles corresponding to equations (1), (2), and (3) to the control unit 110. The control unit 110 converts these duty cycles into voltages and adds up the voltages of each phase to obtain the value A shown in equation (4) below. A=Vf(U)+Vf(V)+Vf(W)+6IR...(4)

[0036] On the other hand, in the second switching, the voltage between terminal IN and terminal GND of the temperature detection circuit 130 is expressed by the following equations (5), (6), and (7) for each of the two phases. Vf(U)+Vf(V)+2IR ···(5) Vf(V)+Vf(W)+2IR ···(6) Vf(W)+Vf(U)+2IR ···(7)

[0037] The temperature detection circuit 130 outputs duty cycles corresponding to equations (5), (6), and (7) to the control unit 110. The control unit 110 converts these duty cycles into voltages and adds up the voltages of each phase to obtain the value B shown in the following equation (8). B=2Vf(U)+2Vf(V)+2Vf(W)+6IR...(8)

[0038] The control unit 110 repeats the first and second switching of the temperature sensing elements T1, T2, and T3 at predetermined intervals. Alternatively, it normally performs the first switching, and only performs the second switching for a predetermined time when it becomes necessary to determine the voltage IR of the offset resistors R1 and R2. Then, the obtained values ​​A and B are applied to the following equation (9) to determine the voltage IR of the offset resistors R1 and R2. IR = (2 * AB) / 6 ... (9)

[0039] Then, by subtracting 2IR from the voltages obtained using equations (1), (2), and (3), the voltage component of the offset resistor is excluded to obtain Vf(U), Vf(V), and Vf(W), and the temperature is calculated by referring to the voltage-temperature characteristics of the temperature-sensing elements T1, T2, and T3. In this case, the voltage-temperature characteristics of the temperature-sensing elements T1, T2, and T3 are voltage-temperature characteristics that do not include the voltage component of the offset resistor and are not affected by fluctuations in the offset resistor.

[0040] Alternatively, the voltage IR across offset resistors R1 and R2 may be determined by performing a third switching operation, which selects all phases of the temperature sensing elements T1, T2, and T3, at appropriate intervals. In this case, the value C shown in equation (10) below is obtained. C=Vf(U)+Vf(V)+Vf(W)+2IR...(10)

[0041] Then, the obtained value C and the value A obtained in equation (4) are substituted into the following equation (11) to find the voltage IR across the offset resistors R1 and R2. IR = (AC) / 4 ... (11)

[0042] In the example of excluding the voltage component of the offset resistor in this embodiment, in addition to achieving the same effects as the first and second switching methods, the influence of the offset resistor is eliminated, enabling highly accurate temperature detection.

[0043] [Second Embodiment] Figure 4 is a circuit diagram of the inverter control device 100 in a second embodiment of the present invention. In the first embodiment, the control unit 110 outputs command signals DO1, DO2, and DO3 to the switching circuit 120 from three signal lines when detecting temperature, but in the second embodiment, it outputs command signals DO1 and DO2 from two signal lines. The same reference numerals are used for parts that are the same as in Figure 1, and their explanations are simplified.

[0044] As shown in Figure 4, the command signals DO1 and DO2 are input to the logic circuit 124. The logic circuit 124 is a decoder circuit logically constructed using or gates and knot gates, and outputs signals to three output lines L1, L2, and L3 according to the combination of the two input command signals DO1 and DO2. Output lines L1, L2, and L3 are connected to the gate sides of the switching elements S1, S2, and S3, respectively. The command signals DO1 and DO2 illustrate the case where the temperature sensing elements T1, T2, and T3 are turned on / off in the first switching operation.

[0045] Figures 5(a) to 5(e) are timing charts showing the switching of temperature sensing elements T1, T2, and T3 in the second embodiment. Figures 5(a) to 5(b) show the timing charts for command signals DO1 and DO2, and Figures 5(c) to 5(e) show the timing charts for switching elements S1, S2, and S3.

[0046] For example, in the first switching operation, as shown in Figures 5(c) to 5(e), one of the switching elements S1, S2, and S3 is turned off, and the other two are turned on. The on / off switching of the switching elements S1, S2, and S3 is performed by combining two command signals DO1 and DO2.

[0047] According to this embodiment, in addition to achieving the same effects as described in the first switching of the first embodiment, the number of output terminals of the control unit 110, which is composed of a microcontroller or the like, can be reduced, and the number of insulating elements 121A can also be reduced, thereby simplifying the configuration and reducing costs.

[0048] [Third Embodiment] Figure 6 is a circuit diagram of the inverter control device 100 in a third embodiment of the present invention. In the first and second embodiments, the temperature detection circuit 130 detects the voltage between terminal IN and terminal GND, but terminal GND uses the potential of the ground on the high-voltage side HV. In this embodiment, terminal GND uses the potential of the ground side of the power module corresponding to the switched-off switching element. The same reference numerals are used for parts that are the same as in Figures 1 and 2, and their explanations are simplified.

[0049] As shown in Figure 6, the GND terminal of the temperature detection circuit 130 is connected to grounds GND_UN, GND_VN, and GND_WN, respectively, via ground potential supply elements G1, G2, and G3. Grounds GND_UN, GND_VN, and GND_WN are the potentials of the ground side (negative side) of the U-phase power module 200U, V-phase power module 200V, and W-phase power module 200W, respectively. A load such as a motor driven by AC current is connected to the output side of the power module 200, and the potential of the ground side (negative side) of the power module 200 is used.

[0050] The outputs of output lines L1, L2, and L3 from the logic circuit 124 are input to the gates of the ground potential supply elements G1, G2, and G3 via knot gates. In the first embodiment shown in Figure 1, the logic circuit 124 is not used, but when applying the third embodiment to the first embodiment, the outputs of output lines L1, L2, and L3 can be input to the gates of the ground potential supply elements G1, G2, and G3 via knot gates.

[0051] Switching elements S1, S2, and S3 that do not have voltage VCC1 supplied to their gates via output lines L1, L2, and L3 are turned off. Then, the voltages of the temperature sensing elements T1, T2, and T3 corresponding to the turned-off switching elements S1, S2, and S3 are detected. In this case, the ground potential supply elements G1, G2, and G3 corresponding to the turned-off switching elements S1, S2, and S3 are turned on, and the corresponding grounds GND_UN, GND_VN, and GND_WN are connected.

[0052] Figures 7(a) to 7(h) are timing charts showing the switching of ground potential supply elements G1, G2, and G3 in the third embodiment. Figures 7(a) to 7(b) show the command signals DO1 and DO2, Figures 7(c) to 7(e) show the timing charts of the switching elements S1, S2, and S3, and Figures 7(f) to 7(h) show the timing charts of the ground potential supply elements G1, G2, and G3.

[0053] Figures 7(a) to 7(e) are similar to Figures 5(a) to 5(e) shown in the second embodiment, and the switching elements S1, S2, and S3 are turned on / off according to the command signals DO1 and DO2. Then, as shown in Figures 7(f) to 7(h), the ground potential supply elements G1, G2, and G3 corresponding to the switched elements S1, S2, and S3 that are turned off are turned on.

[0054] According to this embodiment, in addition to achieving the same effects as described in the first and second embodiments, the influence of potential fluctuations on the output side of the power module 200 can be suppressed, and the accuracy of temperature detection is improved.

[0055] According to the embodiments described above, the following effects and advantages can be obtained. (1) The inverter control device 100 includes a plurality of temperature sensing elements T1, T2, T3 provided in correspondence with a plurality of switching elements 200E, a temperature detection circuit 130 that receives detection signals from the temperature sensing elements T1, T2, T3 and outputs temperature detection information, a control unit 110 that calculates the temperature of the switching elements 200E based on the temperature detection information, and a switching circuit 120 that switches the detection signals from the plurality of temperature sensing elements T1, T2, T3 and outputs them to the temperature detection circuit 130. The control unit 110 operates the switching circuit 120 to select the detection signals to be output from the temperature sensing elements T1, T2, T3 to the temperature detection circuit 130. This simplifies the configuration of the inverter control device.

[0056] (modified version) The present invention can be implemented by modifying the first to third embodiments described above as follows. (1) In each embodiment, an example is shown in which the switching circuit 120, temperature detection circuit 130, and drive circuit 140 are provided individually, but some of these circuits may be incorporated into the same IC circuit. For example, the switching circuit 120, temperature detection circuit 130, and drive circuit 140 may be incorporated into the same IC circuit.

[0057] The present invention is not limited to the embodiments described above, and other forms conceivable within the scope of the technical concept of the present invention are also included within the scope of the present invention, as long as they do not impair the features of the present invention. Furthermore, the above embodiments may be combined with multiple modifications. [Explanation of symbols]

[0058] 100...Inverter control device, 100C...Connection section, 110...Control unit, 120...Switching circuit, 121A...Insulation element, 130...Temperature detection circuit, 140...Drive circuit, 200...Power module, 200U...U-phase power module, 200V...V-phase power module, 200W...W-phase power module, 200E...Switching element, 200I...IGBT, 200D...Diode, T1, T2, T3...Temperature sensing element, S1, S2, S3...Switching element, R1, R2...Offset resistor, DO1, DO2, DO3...Command signal, HV...High voltage side, LV...Low voltage side.

Claims

1. Multiple temperature-sensing elements are provided to correspond to multiple switching elements and are connected to a current path through which current is supplied, A temperature detection circuit that receives a detection signal from the aforementioned temperature sensing element and outputs temperature detection information, A control unit that calculates the temperature of the switching element based on the temperature detection information, The device comprises a plurality of temperature sensing elements and a plurality of switching elements connected in parallel to each of the plurality of switching elements, and a switching circuit that switches the state of the current supply from the current path to the plurality of temperature sensing elements by turning each of the plurality of switching elements on or off, The control unit selects the detection signal to be output from the multiple temperature sensing elements to the temperature detection circuit by switching the current path by controlling the on / off state of each of the multiple switching elements. Each of the aforementioned switching elements is sealed in each phase of the three-phase power module. An inverter control device that supplies the potential of the ground side of the power module corresponding to the switched-off switching element as the potential of the ground side of the current path.

2. In the inverter control device according to claim 1, An inverter control device comprising a ground potential supply element that switches the potential on the ground side of the current path.

3. In the inverter control device according to claim 1 or 2, The temperature sensing element is supplied with the current via an offset resistor. The control unit is an inverter control device that determines the resistance voltage across the offset resistor based on the voltage across each of the temperature sensing elements including the offset resistor and the voltage across multiple temperature sensing elements including the offset resistor, and calculates the temperature of the multiple switching elements based on the voltage across each of the temperature sensing elements, excluding the resistance voltage.

4. In the inverter control device according to claim 1 or 2, The control unit outputs a command signal to the switching circuit to switch the output of the detection signal. The switching circuit is an inverter control device that includes a logic circuit that turns the switching element on and off according to the combination of the command signals.

5. In the inverter control device according to claim 1 or 2, An inverter control device comprising a drive circuit for driving the plurality of switching elements.

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