Inverter control device

Abstract

An inverter control device is provided with: a plurality of temperature sensing elements provided corresponding to a plurality of switching elements; the temperature detection circuit is used for receiving a detection signal from the temperature sensing element and outputting temperature detection information; a control unit that calculates the temperature of the switching element 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, and the control unit operates the switching circuit and selects the detection signals output from the temperature sensing elements to the temperature detection circuit.

Description

Technical Field

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

[0002] In temperature detection using a temperature sensing element such as a temperature sensing diode, a temperature detection circuit is provided to output a detection signal detected by the temperature sensing element to a control unit such as a microcomputer. For example, in an inverter, the temperature sensing element is provided on the high voltage side, and a control unit such as a microcomputer that monitors the temperature detection information is provided on the low voltage side, but a plurality of temperature detection circuits are provided corresponding to the plurality of temperature sensing elements, and the plurality of temperature detection circuits include a circuit that separates the temperature sensing element and the control unit by an insulating element.

[0003] In Patent Document 1, temperature-sensitive diodes for detecting the temperature of switching elements of the inverter are provided corresponding to the switching elements, and temperature detection circuits composed of a voltage detection circuit, a pulse signal output circuit, a photocoupler, etc. are provided corresponding to the temperature-sensitive diodes. Prior art literature Patent Literature

[0004] Patent Document 1: Japanese Patent Application Publication No. 2013-250175 Summary of the invention Problem that the invention aims to solve

[0005] In the device described in Patent Document 1, a plurality of temperature detection circuits are required to correspond to a plurality of temperature sensing elements, and the structure of the inverter control device becomes complicated. Technical means of solving problems

[0006] The inverter control device of the present invention comprises: a plurality of temperature sensing elements, which are arranged corresponding to a plurality of switching elements; a temperature detection circuit, which receives detection signals from the temperature sensing elements and outputs temperature detection information; a control unit, which calculates the temperature of the switching element based on the temperature detection information; and a switching circuit, which switches the detection signals from the plurality of temperature sensing elements and outputs them to the temperature detection circuit, wherein the control unit activates the switching circuit and selects the detection signal output from the temperature sensing element to the temperature detection circuit. Effects of the Invention

[0007] According to the present invention, the structure of the inverter control device can be simplified. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a circuit configuration diagram of the inverter control device according to the first embodiment. Figure 2 (a)~ Figure 2 (f) is a timing diagram showing the first switching of the temperature sensing element. Figure 3 (a)~ Figure 3 (f) is a timing diagram showing the second switching of the temperature sensing element. Figure 4 It is a circuit configuration diagram of an inverter control device according to a second embodiment. Figure 5 (a)~ Figure 5 (e) is a timing chart showing switching of the temperature sensing element in the second embodiment. Figure 6 It is a circuit configuration diagram of an inverter control device according to a third embodiment. Figure 7 (a)~ Figure 7 (h) is a timing chart showing switching of the ground potential supply element in the third embodiment. DETAILED DESCRIPTION

[0009] Hereinafter, the embodiments of the present invention will be described with reference to the accompanying drawings. The following description and the accompanying drawings are examples for illustrating the present invention. In order to make the description clear, appropriate omissions and simplifications have been made. The present invention may also be implemented in various other ways. Unless otherwise specified, each constituent element may be singular or plural.

[0010] In order to facilitate understanding of the invention, the position, size, shape, range, etc. of each component shown in the drawings may not represent the actual position, size, shape, range, etc. Therefore, the present invention is not necessarily limited to the position, size, shape, range, etc. disclosed in the drawings.

[0011] [First embodiment] Figure 1 It is a circuit configuration diagram of the inverter control device 100 according to the first embodiment of the present invention.

[0012] The inverter control device 100 is connected to the power module 200 and controls driving of the power module 200 . The power module 200 includes a U-phase power module 200U, a V-phase power module 200V, and a W-phase power module 200W.

[0013] The U-phase power module 200U has a switching element 200E corresponding to the upper arm and the lower arm, respectively. Each switching element 200E is composed of an IGBT200I and a diode 200D. A temperature sensing element T1 is provided corresponding to the switching element 200E of the upper arm or the lower arm. In addition, the U-phase power module 200U incorporates the switching element 200E of the upper arm, the switching element 200E of the lower arm, and the temperature sensing element T1 into a package and is sealed by a resin member. Similarly, the V-phase power module 200V incorporates the switching element 200E of the upper arm, the switching element 200E of the lower arm, and the temperature sensing element T2 into a package. Similarly, the W-phase power module 200W incorporates the switching element 200E of the upper arm, the switching element 200E of the lower arm, and the temperature sensing element T3 into a package.

[0014] In addition, the switch 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 a diode 200D is provided as needed. In addition, the power module 200 is described as a 2in1 structure in which both the upper arm and the lower arm are integrated into one module, but it can also be another structure such as a structure in which multiple upper arms and lower arms are integrated into one module.

[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. Then, by inputting a drive signal to the gate terminal of the IGBT 200I, the switching element 200E is controlled to be turned on and off, and the DC voltage input between the positive and negative sides of the power module 200 is converted into AC power. The converted AC power is energized from the connection ends of the upper arm and the lower arm to the windings of each phase of the motor (not shown) 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 portion 100C such as a connector. A control unit 110 is configured 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, and mutual 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 based on a torque command input from a higher-level control device (not shown). In addition, 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 the switching circuit 120 described later, so that the switching circuit 120 is activated and the detection signal output from the temperature sensing elements T1, T2, and T3 to the temperature detection circuit 130 described later is selected. 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 sensing elements T1, T2, T3 as the detection objects according to the command signals DO1, DO2, DO3. Specifically, the detection signals from the temperature sensing elements T1, T2, T3 are switched by switching the current paths of the currents supplied to the temperature sensing elements T1, T2, T3 as the detection objects according to the command signals DO1, DO2, DO3.

[0020] The command signals DO1, DO2, and DO3 output from the control unit 110 are respectively input to the insulating element 121A. The insulating element 121A is, for example, an optical coupler in which a light-emitting element and a light-receiving element are sealed 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 of the switching elements S1, S2, and S3 to the light-receiving element side via the resistor 123C. The switching elements S1, S2, and S3 are turned on when the voltage VCC1 is supplied to the gate side thereof, and are turned off when the voltage VCC1 is not supplied. Each switching element S1, S2, and S3 is connected in parallel to each temperature sensing element T1, T2, and T3 provided on each phase of the power module 200.

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

[0022] The temperature detection circuit 130 detects the voltage between the terminal IN and the 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 the voltage, and outputs it from the OUT terminal to the control unit 110 as temperature detection information. The bias resistors R1 and R2 are used to set a bias on the voltage between the terminal IN and the terminal GND, and adjust it to be within the range of the input voltage specification 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 stored in advance. In addition, the temperature detection circuit 130 is described as an example of outputting a duty cycle wave as temperature detection information, but it can also be other forms of information that the control unit 110 can interpret.

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

[0024] Figure 2 (a)~ Figure 2 (f) is a timing chart showing the first switching of the temperature sensing elements T1, T2, and T3. Figure 2 (a)~ Figure 2 (c) is the timing diagram of the command signals DO1, DO2, and DO3. Figure 2 (d)~ Figure 2 (f) is a timing diagram of the switching elements S1, S2, and S3.

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

[0026] For example, when the switching element S1 is turned off and the switching elements S2 and S3 are turned on, current is only supplied to the temperature sensing element T1 of the U-phase power module 200U, and as a result, the temperature sensing element T1 of the U-phase power module 200U is in an operating state at this moment. The temperature detection circuit 130 detects the voltage between the terminal IN and the terminal GND, that is, (the voltage of the temperature sensing element T1 + the voltage of the bias resistor R1 + the voltage of the bias resistor R2), converts the detected voltage into a duty cycle wave corresponding to the voltage, and outputs it to the control unit 110 from the OUT terminal. The control unit 110 converts the duty cycle wave detected at this moment into a voltage, and calculates the temperature by referring to the voltage-temperature characteristic 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 the switching element S2 is turned off and the switching elements S1 and S3 are turned on, and the temperature of the W-phase power module 200W is calculated when the switching element S3 is turned off and the switching elements S1 and S2 are turned on.

[0027] According to the first switching of the temperature sensing elements T1, T2, and T3 of the present embodiment, the temperature of the power module 200 of each phase can be detected while switching the switching elements S1, S2, and S3, so that the temperature of the three phases can be detected by one temperature detection circuit 130, and the structure of the inverter control device 100 can be simplified compared with the case of having a temperature detection circuit 130 for three phases, and the cost of the structure can be reduced. In addition, in the case of having a temperature detection circuit 130 for three phases, current always flows through the temperature sensing elements T1, T2, and T3, but in the present embodiment, the period of the current flowing through the temperature sensing elements T1, T2, and T3 is shortened to one third by switching the switching circuit 120, so that the life of the temperature sensing elements T1, T2, and T3 can be extended, the reliability of the temperature sensing elements T1, T2, and T3 can be improved, and the reliability of temperature detection can be improved. Furthermore, in the case of a three-phase temperature detection circuit 130, current is supplied to the temperature sensing elements T1, T2, and T3 for each phase, but in this embodiment, since the supplied current is used in common, the deviation of the current of each phase is eliminated, and the accuracy of temperature detection can be improved.

[0028] Figure 3 (a)~ Figure 3 (f) is a timing chart showing the second switching of the temperature sensing elements T1, T2, and T3. Figure 3 (a)~ Figure 3 (c) is the timing diagram of the command signals DO1, DO2, and DO3. Figure 3 (d)~ Figure 3 (f) is a timing diagram of the switching elements S1, S2, and S3.

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

[0030] For example, when the temperature sensing elements T1 and T2 of the U-phase power module 200U and the V-phase power module 200V are selected, the switching elements S1 and S2 are turned off, and the switching element S3 is turned on. At this moment, 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, and current is not supplied to the temperature sensing element T3 of the W-phase power module 200W.

[0031] As a result, at this moment, the temperature detection circuit 130 detects the voltage between the terminal IN and the terminal GND, that is, (the voltage of the temperature sensing elements T1 and T2 connected in series + the voltage of the bias resistor R1 + the voltage of the bias resistor R2). Then, the detected voltage is converted into a duty cycle wave corresponding to the voltage and output from the OUT terminal to the control unit 110. The control unit 110 converts the duty cycle wave detected at this moment into a voltage, and calculates the temperature by referring to the voltage-temperature characteristics of the temperature sensing elements T1 and T2. Then, the average detected temperature of the U-phase power module 200U and the V-phase power module 200V is calculated based on the temperature. 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 also calculated.

[0032] According to the second switching of the temperature sensing elements T1, T2, and T3 of the present embodiment, as in the first switching, the structure of the inverter control device 100 can be simplified and the cost of the structure can be reduced compared with the case of having a three-phase temperature detection circuit 130. In addition, by switching the switching circuit 120, the period of the current flowing through the temperature sensing elements T1, T2, and T3 is shortened to two-thirds, so that the life of the temperature sensing elements T1, T2, and T3 can be extended, thereby improving reliability. Furthermore, since the supplied current is used in common, the deviation of the current of each phase can be eliminated, thereby improving the accuracy of temperature detection.

[0033] Next, an example of the first switching and the second switching using the temperature sensing elements T1, T2, and T3 in combination is described. In the following description, the current value supplied to the temperature sensing elements T1, T2, and T3 is represented by I, and the resistance value of the bias resistor R1 and the bias resistor R2 is represented by R.

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

[0035] The temperature detection circuit 130 outputs a duty cycle wave corresponding to equations (1), (2), and (3) to the control unit 110. The control unit 110 converts the duty cycle wave into a voltage, adds the voltages of each phase, and obtains a value A shown in the following equation (4). A=Vf(U)+Vf(V)+Vf(W)+6IR · · · (4)

[0036] On the other hand, in the second switching, the voltage between the terminal IN and the terminal GND of the temperature detection circuit 130 is expressed by the following equations (5), (6), and (7) in 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 a duty cycle wave corresponding to equations (5), (6), and (7) to the control unit 110. The control unit 110 converts the duty cycle wave into a voltage, adds the voltages of each phase, and obtains a value B shown in the following equation (8). B=2Vf(U)+2Vf(V)+2Vf(W)+6IR···(8)

[0038] The control unit 110 repeatedly performs the first switching and the second switching of the temperature sensing elements T1, T2, and T3 at predetermined intervals. Alternatively, the first switching is usually performed, and when the voltage IR of the bias resistors R1 and R2 below needs to be obtained, the second switching is performed only at a predetermined time. Then, the obtained values ​​A and B are inserted into the following formula (9) to obtain the voltage IR of the bias resistors R1 and R2. IR=(2*AB) / 6· · · (9)

[0039] Then, by subtracting 2IR from the voltage obtained by equations (1), (2), and (3), the voltage portion of the bias resistor is excluded, and Vf(U), Vf(V), and Vf(W) are obtained, and the temperature is calculated by referring to the voltage-temperature characteristics of the temperature sensing elements T1, T2, and T3. The voltage-temperature characteristics of the temperature sensing elements T1, T2, and T3 at this time are voltage-temperature characteristics that do not include the voltage portion of the bias resistor and are not affected by changes in the bias resistor, etc.

[0040] Alternatively, the third switching of all phases of the temperature sensing elements T1, T2, and T3 may be appropriately performed within a predetermined time to obtain the voltage IR of the bias resistors R1 and R2. In this case, the value C shown in the following equation (10) is obtained. C=Vf(U)+Vf(V)+Vf(W)+2IR···(10)

[0041] Then, the obtained value C and the value A obtained from the formula (4) are inserted into the following formula (11) to obtain the voltage IR of the bias resistors R1 and R2. IR=(AC) / 4 · · · (11)

[0042] According to the example of eliminating the voltage component of the bias resistor in this embodiment, in addition to achieving the same effects as the first switching and the second switching, the influence of the bias resistor can be eliminated to perform high-precision temperature detection.

[0043] [Second embodiment] Figure 4 1 is a circuit diagram of an inverter control device 100 according to 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 the temperature. However, in the second embodiment, the command signals DO1 and DO2 are output from two signal lines. Figure 1 The same parts are denoted by the same symbols and their descriptions are simplified.

[0044] like Figure 4 As shown, the command signals DO1 and DO2 are input to the logic circuit 124. The logic circuit 124 is a decoder circuit composed of logic such as an OR gate and a NOT gate, and outputs signals to three output lines L1, L2, and L3 according to the combination of the dual-input command signals DO1 and DO2. The output lines L1, L2, and L3 are connected to the gate side of the switching elements S1, S2, and S3, respectively. Regarding the command signals DO1 and DO2, the case of turning on / off the temperature sensing elements T1, T2, and T3 by the first switching is exemplified.

[0045] Figure 5 (a)~ Figure 5(e) is a timing chart showing switching of the temperature sensing elements T1 , T2 , and T3 in the second embodiment. Figure 5 (a)~ Figure 5 (b) is a timing diagram showing the command signals DO1 and DO2. Figure 5 (c)~ Figure 5 (e) is a timing chart showing the switching elements S1, S2, and S3.

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

[0047] According to this embodiment, in addition to achieving the same effect as described in the first switching of the first embodiment, the number of output terminals of the control unit 110 composed of a microcomputer etc. can be reduced, and the number of insulating elements 121A can be reduced, thereby simplifying the structure and reducing costs.

[0048] [Third Embodiment] Figure 6 1 is a circuit diagram of an inverter control device 100 according to a third embodiment of the present invention. In the first and second embodiments, the temperature detection circuit 130 detects the voltage between the terminal IN and the terminal GND, but the terminal GND uses the ground potential of the high voltage side HV. In this embodiment, the terminal GND uses the potential of the ground side of the power module corresponding to the disconnected switching element. Figure 1 , Figure 2 The same parts are denoted by the same symbols and their descriptions are simplified.

[0049] like Figure 6 As shown, the terminal GND of the temperature detection circuit 130 is connected to the ground GND_UN, GND_VN, and GND_WN via the ground potential supply elements G1, G2, and G3, respectively. The ground GND_UN, the ground GND_VN, and the ground GND_WN are the potentials of the ground side (negative side) of the U-phase power module 200U, the V-phase power module 200V, and the W-phase power module 200W, respectively. A load such as a motor driven by an 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 from the output lines L1, L2, and L3 of the logic circuit 124 are input to the gates of the ground potential supply elements G1, G2, and G3 via the NOT gates. Figure 1In the first embodiment shown, the logic circuit 124 is not used. However, when the third embodiment is applied to the first embodiment, the outputs of the output lines L1, L2, and L3 can be provided to the gates of the ground potential supply elements G1, G2, and G3 via NOT gates.

[0051] The switching elements S1, S2, S3 to which the voltage VCC1 is not supplied from the output lines L1, L2, L3 to the gate sides of the switching elements S1, S2, S3 are turned off. Then, the voltages of the temperature sensing elements T1, T2, T3 corresponding to the turned off switching elements S1, S2, S3 are detected. In this case, the ground potential supply elements G1, G2, G3 corresponding to the turned off switching elements S1, S2, S3 are turned on, and the corresponding grounds GND_UN, GND_VN, GND_WN are connected.

[0052] Figure 7 (a)~ Figure 7 (h) is a timing chart showing switching of the ground potential supply elements G1 , G2 , and G3 in the third embodiment. Figure 7 (a)~ Figure 7 (b) shows the timing diagram of the command signals DO1 and DO2. Figure 7 (c)~ Figure 7 (e) shows the timing diagram of the switching elements S1, S2, and S3. Figure 7 (f)~ Figure 7 (h) shows a timing chart of the ground potential supply elements G1, G2, and G3.

[0053] Figure 7 (a)~ Figure 7 (e) and the second embodiment shown in Figure 5 (a)~ Figure 5 The same as (e) of FIG. 1 is used to turn on / off the switching elements S1, S2, and S3 according to the command signals DO1 and DO2. Then, as shown in FIG. Figure 7 (f)~ Figure 7 As shown in (h), the ground potential supply elements G1, G2, G3 corresponding to the switched elements S1, S2, S3 which are turned off are turned on.

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

[0055] According to the above-described embodiment, the following effects can be obtained. (1) The inverter control device 100 includes: a plurality of temperature sensing elements T1, T2, and T3, which are provided corresponding to the plurality of switching elements 200E; a temperature detection circuit 130, which receives detection signals from the temperature sensing elements T1, T2, and T3 and outputs temperature detection information; a control unit 110, which calculates the temperature of the switching element 200E based on the temperature detection information; and a switching circuit 120, which switches the detection signals from the plurality of temperature sensing elements T1, T2, and T3 and outputs them to the temperature detection circuit 130. The control unit 110 operates the switching circuit 120 to select the detection signals output from the temperature sensing elements T1, T2, and T3 to the temperature detection circuit 130. Thus, the structure of the inverter control device can be simplified.

[0056] (Variation Example) The present invention can be implemented by modifying the first to third embodiments described above as follows. (1) In each embodiment, the switching circuit 120, the temperature detection circuit 130, and the drive circuit 140 are provided separately, but some of these circuits may be assembled in the same IC circuit. For example, the switching circuit 120, the temperature detection circuit 130, and the drive circuit 140 may be assembled in the same IC circuit.

[0057] The present invention is not limited to the above-described embodiments, and other embodiments that are considered within the scope of the technical concept of the present invention are also included in the scope of the present invention as long as the features of the present invention are not impaired. In addition, a configuration combining the above-described embodiments and a plurality of modified examples is also possible. Explanation of symbols

[0058] 100…inverter control device, 100C…connecting unit, 110…control unit, 120…switching circuit, 121A…insulating element, 130…temperature detection circuit, 140…driving 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…bias resistor, DO1, DO2, DO3…command signal, HV…high voltage side, LV…low voltage side.

Claims

1. An inverter control device, characterized in that: have: A plurality of temperature sensing elements, which are arranged corresponding to the plurality of switch elements; a temperature detection circuit, which receives a detection signal from the 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; as well as a switching circuit that switches the detection signals from the plurality of temperature sensing elements and outputs them to the temperature detection circuit, The control unit operates the switching circuit to select the detection signal output from the temperature sensing element to the temperature detection circuit.

2. The inverter control device according to claim 1, characterized in that: The plurality of temperature sensing elements are connected to a current path for supplying current, The switching circuit switches the current paths to the plurality of temperature sensing elements, and switches the detection signal by selecting supply of the current to the temperature sensing elements.

3. The inverter control device according to claim 2, characterized in that: The switching circuit includes a switching element connected in parallel with the temperature sensing element. The control unit controls the switching element to switch the current path.

4. The inverter control device according to claim 3, characterized in that: The plurality of temperature sensing elements are connected in series in the current path, The switching circuit stops supplying the current to the corresponding temperature sensing element when the switching element is turned on, and supplies the current to the corresponding temperature sensing element when the switching element is turned off. The control unit performs on-off control on the switching element to select the detection signal.

5. The inverter control device according to claim 4, characterized in that: The plurality of switch elements are respectively sealed in each phase of the three-phase power module. The potential on the ground side of the power module corresponding to the switched element that is turned off is supplied as the potential on the ground side of the current path.

6. The inverter control device according to claim 5, characterized in that: The inverter control device includes a ground potential supply element that switches the potential on the ground side of the current path.

7. The inverter control device according to any one of claims 3 to 6, characterized in that: The current is supplied to the temperature sensing element via a bias resistor. The control unit obtains a resistance voltage applied to the bias resistor based on a voltage applied to each of the temperature sensing elements including the bias resistor and a voltage applied to a plurality of the temperature sensing elements including the bias resistor, and calculates the temperature of the plurality of switching elements based on a voltage applied to each of the temperature sensing elements excluding the resistance voltage.

8. The inverter control device according to any one of claims 3 to 6, characterized in that: The control unit outputs a command signal to the switching circuit for switching the output of the detection signal, The switching circuit includes a logic circuit that turns the switching element on and off according to a combination of the command signals.

9. The inverter control device according to any one of claims 3 to 6, characterized in that: The inverter control device includes a drive circuit that drives the plurality of switching elements.

Images