JP5359604B2 - Control device for power conversion circuit - Google Patents

Description

  The present invention is applied to a vehicle system provided in an in-vehicle high voltage system in which a power switching element constituting a power conversion circuit and temperature detecting means for detecting the temperature thereof are insulated from the in-vehicle low voltage system, and is detected by the temperature detecting means. The present invention relates to a control device for a power conversion circuit for transmitting information on the temperature to be transmitted to the low voltage system.

  As this type of system, for example, as shown in Patent Document 1 below, it is well known that a temperature sensitive diode is used as a temperature detecting means of a power switching element that constitutes an inverter connected to an in-vehicle main machine. Since the temperature sensitive diode changes the output voltage in accordance with the temperature, the output voltage can be used as a temperature detection value. However, when outputting the output voltage of a temperature sensitive diode mounted in a high voltage system to a low voltage system insulated from this, it is necessary to use a means for transmitting a signal while insulating the two systems. Arise. As such means, there is a problem in that, when a means for directly transmitting an analog signal output from a temperature sensitive diode is used, for example, when an isolation amplifier is used, the circuit is complicated or the cost is increased. Arise. Therefore, conventionally, means for transmitting a binary signal such as a photocoupler has been used as such means.

JP 2006-344721 A

  By the way, when transmitting information related to temperature detection by the temperature sensing diode to the low voltage system using the photocoupler or the like, a binary signal (Temperature information representing the temperature information by the time ratio of the analog signal output from the temperature sensing diode) Means for converting the signal into a time ratio signal), and the temperature detection error may be increased by this means, a photocoupler, or the like.

  In addition to the above-mentioned temperature-sensitive diodes, in the case of transmitting information about the temperature detected by the temperature detecting means mounted in the high voltage system to the low voltage system, the detection error is enlarged in the information transmission process. These fears are generally common.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to transmit information on the temperature detected by the temperature detection means mounted in the high voltage system to the low voltage system. An object of the present invention is to provide a control device for a power conversion circuit that can suitably suppress an increase in detection error.

  Hereinafter, means for solving the above-described problems and the operation and effect thereof will be described.

The invention according to claim 1 is applied to a vehicle system provided in an in-vehicle high voltage system in which a power switching element constituting a power conversion circuit and a temperature detecting means for detecting the temperature thereof are insulated from the in-vehicle low voltage system. In the control device of the power conversion circuit that transmits information related to the temperature detected by the detection means to the low voltage system, processing for processing digital data that is data expressed by discrete numerical values in the high voltage system And a management unit having a function of managing the state of the power conversion circuit with the digital data as a processing target in the low-voltage system, and the processing unit captures an output signal of the temperature detection unit The digital data corresponding to the temperature information expressed by the output signal is output to the management means. Is intended to perform the power conversion circuit is one comprising a circuit for series connection of a pair of power switching elements consisting of the power switching element and the low potential side of the power switching elements on the high potential side is connecting in parallel a plurality The detection target of the temperature detection means is the low-potential side power switching element, and the processing means uses the potential of the output terminal of the low-potential side power switching element as a reference potential, A substrate on which a conductive region having the same potential as the output terminal of the power switching element on the potential side and the output terminal of the power switching element on the low potential side is formed, and the substrate on which the processing means is mounted is a separate substrate. Mounted on the multilayer substrate and the processing means has the same potential as the output terminal of the power switching element on the low potential side. A potential of the conductive region is used as a reference potential by being connected to the conductive region, and the temperature detection means uses a voltage between a pair of terminals as an output signal, and the pair of terminals One of them is connected to the processing means through a conductive region having the same potential as the output terminal of the power switching element on the low potential side .

When digital data is transferred from a high voltage system to a low voltage system, there is no error in the data. In the above invention, in view of this point, the temperature information based on the detection by the temperature detecting means is processed into digital data in the high voltage system by mounting the processing means in the high voltage system. Thereby, the expansion of the detection error can be suitably suppressed.
The temperature detection means is normally connected to the output terminal of the power switching element to be temperature detected. On the other hand, all of the power switching elements on the low potential side have the same potential at their output terminals. For this reason, the processing means sets the potential of the output terminal of the power switching element on the low potential side as the reference potential, so that the temperature detection information can be easily obtained by the processing means for the power switching element on the low potential side. .
When a current flows through the electrical path, a voltage drop due to this current occurs, so that a potential difference occurs in the electrical path. On the other hand, when the multilayer substrate is used, the area of the conductive region can be increased. In addition, since the resistance value of the conductive region is small and the current density is small, a potential difference is hardly generated. In the above invention, in view of this point, by connecting the temperature detection means and the processing means via the conductive region, the potential difference between the reference potential of the processing means and the reference potential of the temperature detection means is suitably set. Can be suppressed.

  According to a second aspect of the invention, in the first aspect of the invention, the processing means includes an analog-to-digital conversion means for converting an analog signal output from the temperature detection means into the digital data, and the conversion is performed. Digital data is output to the management means.

The invention described in claim 3 is the invention described in claim 1 or 2 , characterized in that the processing means generates and outputs an operation signal for operating the power conversion circuit.

An operation signal can be transmitted to the power switching element on the low potential side without using an insulating means.

The invention according to claim 4 is the invention according to claim 3 , wherein the power conversion circuit is connected to a multi-phase rotating machine as an in-vehicle main unit, and the management means controls the multi-phase rotating machine. An amount command value is output to the processing means, and the processing means generates and outputs an operation signal for operating the power conversion circuit based on the control amount command value. To do.

These power switching elements can be operated by the processing means without providing an insulating means between the power switching element on the low potential side and the processing means.

According to a fifth aspect of the present invention, in the third aspect of the present invention, the power conversion circuit includes a converter that converts an input voltage and outputs the converted voltage, and the management unit performs the processing on a command value of the output voltage of the converter. And the processing means generates and outputs an operation signal for operating the converter based on a command value of the output voltage.

The invention according to claim 6 is the invention according to any one of claims 1 to 5 , wherein wirings for connecting the pair of terminals of the temperature detection means to the pair of terminals of the processing means are mutually connected. It is characterized by being arranged in parallel.

  In the above invention, by arranging the pair of wirings in parallel, when common mode noise is superimposed on the pair of terminals or the like of the temperature detecting means, the influence can be suitably reduced.

Note that the side as the processing unit corresponding to the reference potential of the pre-Symbol pair of terminals may be characterized in that the common connection point between the conductive region.

The invention according to claim 7 is the invention according to any one of claims 1 to 6 , wherein the temperature detection means uses a voltage between a pair of terminals as an output signal. It further includes a connected differential amplifier circuit, and an output terminal of the differential amplifier circuit is connected to the processing means.

  In the above invention, even if the common mode noise is superimposed on the pair of terminals of the temperature detecting means, it can be canceled by the differential amplifier circuit.

The invention according to claim 8 is the invention according to any one of claims 1 to 7 , wherein the power conversion circuit includes a plurality of power switching elements, and the temperature detecting means includes the plurality of power switching elements. Of these, the one whose temperature is assumed to be high is the temperature detection target.

  The use of the temperature information of the power switching element is usually for determining whether or not the temperature is excessively high. For this reason, when it is provided with a plurality of power switching elements, it is possible to perform appropriate temperature management while reducing the number of temperature detection targets by setting the temperature detection targets to those that are assumed to be high temperature. .

The invention according to claim 9 is the invention according to claim 8 , further comprising cooling means for cooling the plurality of power switching elements with cooling water, wherein the power switching element to be detected by the temperature detection means is the It is arrange | positioned in the flow direction downstream of a cooling water, It is characterized by the above-mentioned.

  Since it is considered that the temperature on the downstream side in the flow direction of the cooling water is higher than that on the upstream side, the temperature of the power switching element arranged on the downstream side is considered to be higher than that on the upstream side.

The figure which shows the system configuration | structure concerning 1st Embodiment. The perspective view which shows the cooling device of the power switching element concerning the embodiment. The circuit diagram which shows the circuit structure of the propagation path of the temperature detection signal concerning the embodiment. The perspective view which shows the structure of the propagation path of the temperature detection signal concerning the embodiment. The figure which shows the conventional system structure. The figure which shows the effect of the said embodiment. The perspective view which shows the structure of the propagation path of the temperature detection signal concerning 2nd Embodiment. The circuit diagram which shows the circuit structure of the propagation path of the temperature detection signal concerning 3rd Embodiment. The figure which shows the modification of each said embodiment. The circuit diagram which shows the circuit structure of the modification of each said embodiment. The perspective view which shows the structure of the propagation path of the temperature detection signal in the modification of each said embodiment.

(First embodiment)
Hereinafter, a first embodiment in which a control device for a power conversion circuit according to the present invention is applied to a hybrid vehicle will be described with reference to the drawings.

  FIG. 1 shows a system configuration according to the present embodiment.

  As shown in the figure, a motor generator 10 as an in-vehicle main machine is connected to a high voltage battery 12 via an inverter IV. The inverter IV is configured by connecting three series-connected bodies of a power switching element Swp on the high potential side and a power switching element Swn on the low potential side in parallel. A connection point between each power switching element Swp and power switching element Swn is connected to each phase of motor generator 10. Further, between the input / output terminals (between the collector and the emitter) of the high potential side power switching element Swp and the low potential side power switching element Swn, there is a high potential side freewheel diode FDp and a low potential side free switching diode. The cathode and anode of the wheel diode FDn are connected.

  A driver unit DU is connected to the conduction control terminals (gates) of the power switching elements Swp and Swn constituting the inverter IV. Each of these driver units DU operates with the emitter to be driven as a reference potential. The driver unit DU is connected to a central processing unit (CPU 20) that operates using the negative potential of the high-voltage battery 12 as a reference potential. Incidentally, the driver unit DU of the high potential side power switching element Swp and the CPU 20 are connected via an interface 22. The interface 22 is constituted by a photocoupler or the like, and is an insulating means that enables signal transmission while insulating the driver unit DU of the high-potential-side power switching element Swp from the CPU 20.

  The CPU 20 is a processing unit that operates on digital data that is data expressed by discrete numerical values. However, the CPU 20 includes an analog / digital converter (A / D converter 20a) for converting analog signals from the outside into digital data that can be processed. The CPU 20 operates operation signals gup, gvp, gwp for operating the power switching elements Swp for the U phase, the V phase, and the W phase of the inverter IV, and the power switching elements Swn based on detection values of various sensors (not shown). Operation signals gun, gvn, and gwn are generated and output. Accordingly, the power switching elements Swp and Swn are operated by the CPU 20 via the driver unit DU.

  The operation signals “gup”, “gvp”, “gwp”, “gun”, “gvn”, and “gwn” are generated based on the required torque output from the electronic control unit (ECU 26). The ECU 26 constitutes a low-voltage system that is insulated from a high-voltage system that includes the high-voltage battery 12, and operates while the vehicle body is set to a reference potential (ground potential). The ECU 26 uses a low voltage battery 28 as a power source for the in-vehicle auxiliary machine as a power source. In addition, since it is necessary to insulate the in-vehicle high voltage system and the in-vehicle low voltage system, communication between the ECU 26 and the CPU 20 is performed via the interface 24 similar to the interface 22 described above.

  The power switching elements Swp and Swn have a high temperature due to a large current flowing therethrough. And when the temperature of the power switching elements Swp and Swn becomes excessively high, there is a concern that the reliability is lowered. Therefore, the power switching elements Swp and Swn are cooled by the cooling device 30 as shown in FIG. FIG. 2 shows that the power card PC in which each of the power switching elements Swp and Swn is accommodated is arranged in the cooling device 30. Here, the cooling device 30 has a structure in which the cooling water flowing in from the inflow port 32 flows out from the outflow port 34 through the cooling passage 36, and power is provided so as to be sandwiched between the pair of cooling passages 36. A card PC is arranged. In particular, the power card PC that accommodates the power switching element Swp on the high potential side is disposed on the upstream side of the cooling device 30 (on the cooling water inlet 32 side), and the power switching on the low potential side so as to be adjacent thereto. A power card PC that accommodates the element Swn is disposed downstream of the cooling device 30 (on the cooling water outlet 34 side).

  The power card PC also houses a temperature sensitive diode SD (FIG. 1) for detecting the temperature of the power switching elements Swp and Swn. Here, the temperature-sensitive diode SD disposed in the vicinity of the power switching element Swn on the low potential side is means for detecting the temperature of the power switching element Swn, as shown in FIG. On the other hand, the temperature sensitive diode SD arranged near the power switching element Swp is not used for temperature detection in the present embodiment. Here, since the power card PC in which the power switching element, the free wheeling diode FD, and the temperature sensing diode SD are packaged is assumed, the temperature sensing diode SD is also disposed in the vicinity of the high potential side power switching element Swp. It is supposed to be.

  Here, the temperature of the power switching element Swn on the low potential side is to be detected from the arrangement in the cooling device 30 of the inverter IV from the power switching elements Swp and Swn constituting the inverter IV. This is because the temperature of the power switching element Swn is considered to be particularly high.

  A temperature detection signal (analog signal) from each temperature-sensitive diode SD that detects the temperature of each of the low-potential-side power switching elements Swn is output to the CPU 20. The CPU 20 converts the temperature detection signal into digital data by the A / D converter 20a, and then outputs this digital data to the ECU 26. The ECU 26 performs a process of limiting the required torque based on the temperature information of the power switching element Swn.

  FIG. 3 shows a temperature detection signal transmission path between the temperature-sensitive diode SD and the CPU 20 according to the present embodiment. As shown in the figure, the driver unit DU of the power switching element Swn includes a constant current source 40 having a power source 42 as a power supply means, and a constant current source for inputting the output current of the constant current source 40 to the temperature sensitive diode SD. Forty output terminals and the anode of the temperature sensitive diode SD are connected. The anode side of the temperature sensitive diode SD is connected to the CPU 20. On the other hand, the cathode side of the temperature sensitive diode SD is set to the same potential as the output terminal (emitter terminal) of the power switching element Swn, like the CPU 20. As a result, the CPU 20 can detect the voltage between the anode and the cathode of the temperature sensitive diode SD, and thus can acquire information on the temperature detected by the temperature sensitive diode SD.

  FIG. 4 shows an actual connection mode between the temperature-sensitive diode SD and the CPU 20.

  As illustrated, in this embodiment, the CPU 20 is mounted on the multilayer substrate 50. The multilayer substrate 50 is formed by mounting or mounting a semiconductor device, wiring, electrodes, or the like on each of a plurality of substrates. In particular, the multilayer substrate 50 includes a ground layer 52 and a mounting layer 56. Here, the ground layer 52 is a layer in which a conductive region having a potential on the output terminal (emitter terminal) side of the power switching elements Swp and Swn is formed. In the figure, the emitter potential of the power switching element Swn on the low potential side is shown. And a conductive region 54 serving as the emitter potential of the power switching element Swp on the U-phase high potential side. In practice, the ground layer 52 is also formed with a conductive region that becomes the emitter potential of the power switching element Swp on the high potential side of each of the V and W phases. On the other hand, the mounting layer 56 is a layer on which the CPU 20 and the like are mounted, and wiring for connecting the CPU 20 and other electronic devices is formed on the surface thereof. The CPU 20 is connected to the conductive region 53 via a wiring (via contact Vc) that penetrates the mounting layer 56 of the multilayer substrate 50. As a result, the CPU 20 operates using the potential of the conductive region 53 as the reference potential.

  The anode of the temperature sensitive diode SD mounted on the power card PC is connected to the multilayer substrate 50 via the plus wiring Lp. Specifically, it is connected to the input terminal of the CPU 20 via the wiring 57 formed in the mounting layer 56. On the other hand, the cathode of the temperature sensitive diode SD is connected to the multilayer substrate 50 via the minus wiring Lm. Specifically, it is connected to the conductive region 53 via a wiring (via contact Vc) that penetrates the mounting layer 56 of the multilayer substrate 50.

  For this reason, the cathode side of the temperature-sensitive diode SD and the CPU 20 are connected via the conductive region 53. The conductive region 53 has a larger current passage area and a smaller resistance value than the wiring formed in the mounting layer 56. Thereby, the difference between the respective reference potentials of the temperature sensitive diode SD and the CPU 20 is sufficiently suppressed. Therefore, the CPU 20 can detect the voltage between the pair of input terminals of the temperature sensitive diode SD with high accuracy.

  Furthermore, by disposing the CPU 20 in the high voltage system, it is possible to improve the accuracy of temperature detection using the temperature sensitive diode SD as compared with the conventional example shown in FIG. In the example shown in FIG. 5, the CPU 20 is arranged in a low voltage system.

  FIG. 6 shows a signal transmission path between the temperature sensitive diode SD and the CPU 20 in the present embodiment and the conventional example. Specifically, FIG. 6A shows the signal transmission path of this embodiment, FIG. 6B shows the signal transmission path of Conventional Example 1, and FIG. 6C shows the signal transmission path of Conventional Example 2. Indicates the route.

  Here, both the conventional example 1 and the conventional example 2 are examples in which the output signal (temperature detection signal) of the temperature sensitive diode SD is output to the CPU 20 via the interface 22 (photocoupler). Thus, the temperature detection signal is converted into a binary signal of logic “H” and logic “L”. The output signal of the PWM signal generator 36 is a signal in which the ratio (duty ratio) of the period of logic “H” to one period of logic “H” and logic “L” expresses temperature information. This ratio is an analog value similar to the voltage value of the output signal of the temperature sensitive diode SD. The difference between Conventional Example 1 and Conventional Example 2 is that the CPU 20 includes a timer 20b for directly detecting the duty ratio or an A / D converter 20a. The conventional example 2 including the A / D converter 20a includes a frequency voltage converter 38 for once converting the time ratio signal into an analog voltage signal.

  FIG. 6D shows the temperature detection error in each of the configurations shown in FIGS. 6A to 6C. In the case of the conventional examples 1 and 2, the detection signal error generated when generating the time ratio signal, the error when the signal is transmitted through the photocoupler (interface 22), and the conversion by the frequency voltage converter 38 Since there is an error or the like, the error is enlarged as compared with the case of the present embodiment. On the other hand, in this embodiment, since such a member is not provided between the CPU 20 and the temperature sensitive diode SD, temperature information finally recognized by the CPU 20 can be made highly accurate. Incidentally, when the temperature information is transmitted from the CPU 20 to the ECU 26, since the transmission target is digital data, no temperature detection error occurs.

  According to the embodiment described in detail above, the following effects can be obtained.

  (1) The CPU 20 is mounted on a high voltage system, and the CPU 20 converts an analog signal output from the temperature sensitive diode SD into digital data and outputs it to the low voltage system. Thereby, the expansion of the temperature detection error using the temperature sensitive diode SD can be suitably suppressed.

  (2) The temperature of the power switching element Swn on the low potential side was set as a detection target. In this case, since all the output terminals of the low-potential-side power switching element Swn have the same potential, the temperature of the low-potential-side power switching element Swn can be detected for all phases without using an insulating means. it can.

  (3) The CPU 20 generates an operation signal for the power switching element Swn. Thereby, an operation signal can be output from the CPU 20 to the power switching element Swn without passing through the insulating means.

  (4) The terminal for taking in the reference potential among the terminals of the CPU 20 and the cathode of the temperature sensitive diode SD are connected via the conductive region 53. Thereby, the reference potential of the temperature sensitive diode SD and the reference potential of the CPU 20 can be made the same.

  (5) Among the plurality of power switching elements Swp and Swn, a temperature detection target (power switching element Swn) that is assumed to increase in temperature is used. Thereby, it is possible to perform appropriate temperature management while reducing the number of temperature detection targets.

  (6) The power switching element Swn is arranged on the downstream side in the flow direction of the cooling water, and this is used as a temperature detection target. As a result, it is assumed that the temperature of the power switching element Swn on the low potential side is increased. Therefore, it is possible to perform appropriate temperature management by setting this as a temperature detection target, and an insulating means is required between the CPU 20 and the power switching element Swn. It is also possible to reduce the number of communication lines.

(Second Embodiment)
Hereinafter, the second embodiment will be described with reference to the drawings with a focus on differences from the first embodiment.

  FIG. 7 shows an actual connection mode between the temperature sensitive diode SD and the CPU 20 according to the present embodiment. In FIG. 7, members corresponding to those shown in FIG. 4 are given the same reference numerals for convenience.

  As shown in the drawing, the plus wiring Lp and the wiring 57 that connect the cathode of the temperature sensitive diode SD and the CPU 20 and the minus wiring Lm and the wiring 58 that connect the anode of the temperature sensing diode SD and the CPU 20 are parallel to each other. Has been placed. Specifically, the wiring 58 is connected to a connection portion between the CPU 20 and the conductive region 53. For this reason, the potential difference between the CPU 20 and the anode of the temperature sensitive diode SD can be ignored. Further, since the plus wiring Lp and the wiring 57 are parallel to the minus wiring Lm and the wiring 58, these wiring lengths are substantially equal. For this reason, even if common mode noise is superimposed on the electrical path connecting the anode and cathode of the temperature-sensitive diode SD and the CPU 20, when the CPU 20 detects a potential difference between the pair of electrical paths, this noise is detected. Will be offset.

  According to the present embodiment described above, the following effects can be obtained in addition to the effects according to the above-described effects of the first embodiment.

  (7) A pair of wires (plus wire Lp and wire 57, minus wire Lm and wire 58) connecting the temperature sensitive diode SD and the multilayer substrate 50 are arranged in parallel. Thereby, the influence of the common mode noise superimposed on these can be suppressed suitably.

(Third embodiment)
Hereinafter, the third embodiment will be described with reference to the drawings with a focus on differences from the second embodiment.

  FIG. 8 shows a temperature detection signal transmission path between the temperature-sensitive diode SD and the CPU 20 according to the present embodiment. In FIG. 8, the same members as those in FIG. 3 are given the same reference numerals for the sake of convenience.

  In the present embodiment, the voltage between the anode and the cathode of the temperature sensitive diode SD is input to the CPU 20 via the differential amplifier circuit 60. Here, the differential amplifier circuit 60 includes an operational amplifier 62, resistors 64 and 66 are connected to the non-inverting input terminal and the inverting input terminal, respectively, and the inverting input terminal and the output terminal are connected by the resistor 68. It has been done. Here, in this embodiment, the cathode side of the temperature-sensitive diode SD is connected to the inverting input terminal, and the non-inverting input terminal that is connected to the anode side is connected to the power switching element Swn via the resistor 69. Connect to the emitter. The resistor 69 is provided in order to increase resistance to noise.

  Since the differential amplifier circuit 60 outputs a signal corresponding to the potential difference between the pair of input terminals, it is possible to suitably remove in-phase noise (common mode noise) superimposed on the pair of input terminals. Incidentally, the differential amplifier circuit 60 is mounted on the mounting layer 56 in the multilayer substrate 50 shown in FIG. Here, it is desirable to connect the wirings 57 and 58 shown in FIG. 7 to the resistors 64 and 66, respectively.

  According to the present embodiment described above, the following effects can be obtained in addition to the effects according to the second embodiment.

  (8) The anode and cathode of the temperature sensitive diode SD are connected to a pair of input terminals of the differential amplifier circuit 60 so that the output signal of the differential amplifier circuit 60 is output to the CPU 20. As a result, even if common mode noise is superimposed on a pair of electrical paths that connect the anode and cathode of the temperature sensitive diode and the pair of terminals of the differential amplifier circuit 60, this can be suitably offset.

(Other embodiments)
Each of the above embodiments may be modified as follows.

  In each of the above embodiments, all the temperatures of the power switching element Swn of the lower arm are temperature detection targets, but the present invention is not limited to this. For example, only one of them may be used. In this case, for example, it is considered that the temperature of the power switching element Swn disposed at the position farthest from the cooling water outlet 34 is likely to be the highest, so this temperature may be the detection target. However, if the setting is considered that the temperature of the power switching element sandwiched between the pair of power switching elements is more likely to be the highest than that disposed at the position farthest away from the outlet 34. Of course, it is possible to set the temperature as a detection target.

  The hybrid vehicle is not limited to one having only one motor generator 10. For example, as shown in FIG. 9 that includes two motor generators (motor generators 10a and 10b), a plurality of motor generators may be provided. 9 includes a converter CV that boosts the voltage of the high-voltage battery 12 in addition to the inverter IV1 connected to the motor generator 10a and the inverter IV2 connected to the motor generator 10b as a power conversion circuit. Was illustrated. Each of the inverters IV1 and IV2 and the converter CV includes a series connection body of a power switching element Swp on the high potential side and a power switching element Swn on the low potential side. For this reason, the potential of the output terminal of the low-potential-side power switching element Swn is equal to the negative electrode potential of the high-voltage battery 12. For this reason, all of these low-potential-side power switching elements Swn can be targeted for temperature detection.

  In the above configuration, the operation signal for the power switching element of inverters IV1 and IV2 and the operation signal for the power switching element of converter CV are both generated by CPU 20 mounted in the high voltage system. Not limited to. For example, only the operation signal of the converter CV may be generated by the CPU 20 mounted in the high voltage system. Even in this case, the temperature detection accuracy can be improved by using the CPU 20 mounted in the high voltage system for the temperature detection process of the power switching element in the high voltage system.

  In each of the above embodiments, the power switching element Swn on the low potential side is the temperature detection target, but the present invention is not limited to this. For example, any one of the power switching elements Swp on the high potential side may be set as a temperature detection target, and the output terminal potential and the input terminal potential of the power switching element Swp may be used as the reference potential of the CPU 20. However, even when the power switching element Swp on the high potential side is a temperature detection target, it is not essential that the potential of the input terminal or output terminal of the power switching element Swp be the reference potential of the CPU 20. For example, as shown in FIG. 10, the cathode potential of the temperature sensitive diode SD that detects the temperature of the power switching element Swp on the high potential side and the reference potential of the CPU 20 are used as the emitter potential of the power switching element Swn on the low potential side. Also good. However, in this case, it is necessary to ensure insulation between the power switching element Swp and the temperature-sensitive diode that detects the temperature.

  The structure of the multilayer substrate 50 is not limited to that illustrated in FIG. For example, as shown in FIG. 11, the conductive region for setting the emitter potential of the power switching element Swn of each phase may be separated. FIG. 11 shows an example in which the conductive region 53a connected to the emitter of the U-phase power switching element Swn and the conductive region 53b connected to the emitter of the V-phase power switching element Swn are separated. Thereby, the situation where the output current from the output terminal of the power switching element Swn flows through the conductive region can be preferably avoided.

  The driver unit DU that drives the high-potential side power switching element Swp and the driver unit DU that drives the low-potential side power switching element Swn may be integrally formed by a high voltage integrated circuit (HVIC). In this case, it is possible to drive all of the power switching elements Swp and Swn constituting the inverter IV by an operation signal of the CPU 20 without providing a photocoupler between the CPU 20 and the driver unit DU.

  The temperature detection means is not limited to a temperature sensitive diode, and is a means that utilizes the temperature characteristics of a PN junction, for example, between the base and emitter of a bipolar transistor or between the source and drain of a MOS field effect transistor. Also good. For example, in the case of using a MOS field effect transistor, the voltage between the source and the drain when the same current flows between the source and the drain has temperature dependence, and the voltage between the source and the drain is converted into the temperature detection signal. You can use as. Further, for example, a thermocouple may be used.

  The power conversion circuit is not limited to the inverter or the converter CV, but may be a DCDC converter that steps down the voltage of the high voltage battery 12 and outputs the voltage to the low voltage battery 28.

  The power conversion circuit is not limited to that mounted on a hybrid vehicle, and may be mounted on an electric vehicle or a fuel cell vehicle, for example.

  In each of the above embodiments, the temperature sensitive diode SD is mounted on both the power card PC mounting the power switching element Swp on the high potential side and the power card PC mounting the power switching element Swn on the low potential side. However, the temperature sensitive diode SD may be mounted only on a device on which a power switching element to be temperature detected is mounted.

  Other than that, for example, a substrate on which the CPU 20 is mounted is not limited to a multilayer substrate. Further, the power switching element is not limited to the IGBT, and may be, for example, a power MOSFET, a bipolar transistor, or the like. Further, the CPU 20 in the high voltage system may be accommodated in the ECU 26 in the low voltage system.

  DESCRIPTION OF SYMBOLS 10 ... Motor generator, 12 ... High voltage battery, 20 ... CPU (one embodiment of a processing means), 26 ... ECU (one embodiment of a management means), 28 ... Low voltage battery, Swp, Swn ... Power switching element, SD ... Temperature sensitive diode.

Claims (9)

The power switching element constituting the power conversion circuit and the temperature detecting means for detecting the temperature thereof are applied to a vehicle system provided in the in-vehicle high voltage system insulated from the in-vehicle low voltage system, and the temperature detected by the temperature detecting means In a control device for a power conversion circuit for transmitting information to the low voltage system,
The high-voltage system includes processing means for processing digital data that is data represented by discrete numerical values,
In the low-voltage system, comprising a management means having a function of managing the state of the power conversion circuit with the digital data as a processing target,
It said processing means receives the output signal of the temperature detecting means, which performs processing for outputting digital data corresponding to the temperature information represented by the output signal to the management means,
The power conversion circuit includes a circuit in which a plurality of series connection bodies of a pair of power switching elements including a power switching element on a high potential side and a power switching element on a low potential side are connected in parallel.
The detection target of the temperature detection means is the power switching element on the low potential side,
The processing means uses a potential of an output terminal of the low-potential side power switching element as a reference potential, an output terminal of the high-potential side power switching element and an output terminal of the low-potential side power switching element And a substrate on which a conductive region having the same potential as each of the substrate and a substrate on which the processing unit is mounted are mounted on a multi-layer substrate which is a separate substrate, and the processing unit is provided on the low potential side. By connecting to a conductive region having the same potential as the output terminal of the power switching element, the potential of the conductive region is used as a reference potential.
The temperature detection means uses a voltage between a pair of terminals as an output signal, and one of the pair of terminals has the same potential as the output terminal of the power switching element on the low potential side. A control device for a power conversion circuit, wherein the control device is connected to the processing means via   The processing means includes analog-to-digital conversion means for converting an analog signal output from the temperature detection means into the digital data, and outputs the converted digital data to the management means. The control apparatus of the power conversion circuit according to 1. 3. The control apparatus for a power conversion circuit according to claim 1, wherein the processing means generates and outputs an operation signal for operating the power conversion circuit. The power conversion circuit is connected to a multiphase rotating machine as an in-vehicle main machine,
The management means outputs a command value of a control amount of the multiphase rotating machine to the processing means,
4. The control apparatus for a power conversion circuit according to claim 3 , wherein the processing means generates and outputs an operation signal for operating the power conversion circuit based on a command value of the control amount. The power conversion circuit includes a converter that converts and outputs an input voltage,
The management means outputs a command value of the output voltage of the converter to the processing means,
4. The control apparatus for a power conversion circuit according to claim 3 , wherein the processing means generates and outputs an operation signal for operating the converter based on a command value of the output voltage. The wiring which connects each of a pair of terminal of the said temperature detection means to each of a pair of said processing means is arrange | positioned in parallel with each other, The one of Claims 1-5 characterized by the above-mentioned. Control device for power conversion circuit. The temperature detection means uses a voltage between a pair of terminals as an output signal,
A differential amplifier circuit connected to the pair of terminals;
Control device for a power conversion circuit according to any one of claims 1 to 6, characterized in that the output terminal of the differential amplifier circuit is connected to said processing means. The power conversion circuit includes a plurality of power switching elements,
The power conversion circuit according to any one of claims 1 to 7 , wherein the temperature detection means targets a temperature detection target among the plurality of power switching elements that is assumed to have a high temperature. Control device. A cooling means for cooling the plurality of power switching elements with cooling water;
9. The control device for a power conversion circuit according to claim 8 , wherein the power switching element to be detected by the temperature detection means is arranged downstream in the flow direction of the cooling water.

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