JP7395975B2 - Power converter reuse system - Google Patents

Description

The technology disclosed in this specification relates to a reuse system for a power conversion device of an electric vehicle.

A power conversion device (typically an inverter) that converts electric power from a power source into driving electric power for a motor for driving generates a large amount of heat, and deteriorates when used for a long period of time. Patent Document 1 discloses a technique for evaluating the remaining life of a power converter installed in a vehicle and communicating whether or not the power converter needs to be replaced based on the evaluation result. If it is determined that replacement is necessary, the vehicle will be taken to a repair shop, where the power converter will be replaced.

Japanese Patent Application Publication No. 2002-119043

Although the replaced power converters are showing signs of deterioration, some of them can be reused. However, in order to evaluate whether the replaced power converter is suitable for reuse, it is necessary to reconnect the power converter to the power supply, motor, etc., and return the power converter to an operational state, which is costly. Bulk. This specification provides a technique for realizing reuse and life extension of a power conversion device at low cost.

The power conversion device reuse system disclosed in this specification includes an inspection device and a determination device. The test device replaces the current control program installed in the power converter with the test program, and acquires data during operation of the power converter that operates under the control of the test program. Then, the determination device determines the degree of deterioration of the power conversion device based on the operating data and determines a rank indicating the degree of deterioration. Thereafter, the inspection device implements, in place of the inspection program, another control program on the power conversion device that can extend the remaining life of the power conversion device more than when controlling with the current control program, according to the determined rank. The operating data is, for example, data related to a power conversion semiconductor device (typically a power transistor) included in the power conversion device.

As a result, the remaining life of the power conversion device can be extended by operations that can be performed at a maintenance site, such as replacing the current control program that was previously installed with another control program. The above-mentioned work can be performed without removing the power converter from the vehicle, so it can be performed in a short time and at low cost. Therefore, it becomes possible to reuse and extend the life of the power conversion device at low cost.

Details of the technology disclosed herein and further improvements will be explained in the embodiments of the invention.

FIG. 2 is a block diagram illustrating a configuration example of a power converter reuse system. FIG. 2 is a block diagram illustrating a configuration example of a power conversion device. It is a flow chart showing an example of test decision processing by a test decision device. FIG. 3 is an explanatory diagram showing an example of a rank determination map.

A power converter reuse system according to an embodiment will be described with reference to the drawings. The performance of a power conversion device (hereinafter referred to as PCU) included in a hybrid vehicle progresses depending on the distance traveled and the number of years of use of the vehicle. Therefore, the reuse system of this embodiment inspects and determines whether or not the PCU 10 included in the hybrid vehicle 2 can be reused and whether or not it needs to be replaced. FIG. 1 shows a block diagram illustrating a configuration example of a reuse system for a PCU 10. As shown in FIG. FIG. 2 shows a block diagram showing a configuration example of the PCU 10.

As shown in FIG. 2, the hybrid vehicle 2 includes an engine 6 and a motor 7 as drive sources for driving. The output torque of the engine 6 and the output torque of the motor 7 are appropriately distributed/combined by a power distribution mechanism 8 and output to a propeller shaft 9. The output of the power distribution mechanism 8 is transmitted to the driving wheels via a transmission (not shown) connected to the propeller shaft 9. It should be noted that FIG. 2 shows only the parts necessary for the explanation of this specification, and the illustration of parts unrelated to the explanation is omitted.

Electric power for driving the motor 7 is supplied from the main battery 3. The main battery 3 has an output voltage of, for example, 300V (volts), and is connected to the PCU 10 via a system main relay 4. The system main relay 4 is a switch that connects and disconnects the main battery 3 and the drive system of the vehicle, and is switched by an unillustrated host controller.

PCU 10 is a power conversion device interposed between main battery 3 and motor 7. The PCU 10 includes a voltage converter 12 that boosts the voltage of the main battery 3 to a voltage suitable for driving the motor 7 (for example, 600 V (volts)), an inverter 14 that converts the boosted DC power into AC, and the voltage converter 12 and The controller 19 controls the inverter 14. The output of the inverter 14 corresponds to the power supplied to the motor 7.

In the PCU 10, electrical components (particularly power cards 13, 15, 16, 17) constituting the voltage converter 12 and the inverter 14 are constantly cooled by a cooling system (not shown). The hybrid vehicle 2 can also use the driving force of the engine or the deceleration energy of the vehicle, that is, when braking, the motor 7 can generate electricity using the kinetic energy of the vehicle. Such power generation is called regeneration. When the motor 7 generates power, the inverter 14 converts alternating current to direct current, and the voltage converter 12 lowers the voltage to a voltage slightly higher than that of the main battery 3 and supplies it to the main battery 3.

The voltage converter 12 is a circuit that mainly includes a reactor, a switching element (semiconductor device for power conversion) such as an IGBT (or power MOSFET), and a capacitor. FIG. 2 shows a power card 13 having switching elements among these. The power card 13 includes two switching elements connected in series, two freewheeling diodes connected in antiparallel to each switching element, and a temperature sensor that detects the temperature of these semiconductor devices. It is packaged in a plate shape as a power module. Power card 13 is sometimes referred to as an intelligent power module (IPM).

The inverter 14 mainly includes three power cards 15, 16, and 17 having switching elements such as two IGBTs (or power MOSFETs) that perform switching operations corresponding to the U, V, and W phases of the motor 7. The circuit is configured as follows. Free wheel diodes are also connected in antiparallel to each of these switching elements. Furthermore, these power cards 15, 16, and 17 are also equipped with a temperature sensor that detects the temperature of the semiconductor device. In this embodiment, these switching elements and their peripheral circuits are also packaged in a plate shape as a power module, similar to the switching elements of the voltage converter 12.

The controller 19 is an information processing device composed of electronic components such as a microcomputer, memory, and input/output interface. This controller 19 is connected to a voltage converter 12, an inverter 14, and a host controller (not shown). In this embodiment, the controller 19 is connected to the control terminals of the power cards 13 and 15-17 that constitute the voltage converter 12 and the inverter 14, and these are controlled by the controller 19. Further, output terminals of each sensor built into the power card 13 or the like are also connected to the controller 19. This allows the controller 19 to obtain data (eg, temperature data, voltage data, current data, etc.) regarding the switching elements (semiconductor devices) of the power cards 13, 15-17.

The voltage converter 12 and the inverter 14 perform switching operations for boosting the voltage and converting the voltage into alternating current based on the PWM signal generated and supplied by the controller 19. A host controller connected to the controller 19 receives, for example, accelerator opening degree information and brake pedal force information as operation information by the driver. Therefore, the operation of the switching elements of each power card 13, 15-17 is performed according to control information according to the accelerator opening degree, etc., input from the host controller.

The power cards 13 and 15-17 of the voltage converter 12 and inverter 14, whose switching elements are controlled in this manner, generate a large amount of heat. Therefore, although these power cards 13 and 15-17 are cooled at any time by being alternately sandwiched between plate-shaped coolers through which refrigerant flows, for example, by an unillustrated PCU cooler, the power cards 13 and 15-17 are Switching elements generate a large amount of heat and do not always operate within an appropriate temperature range. Therefore, the performance of the switching elements of the power cards 13, 15-17 may deteriorate depending on the amount of heat generated and the length of cumulative usage time. In other words, the performance of the PCU 10 of the hybrid vehicle 2 progresses depending on the mileage and years of use of the vehicle.

Therefore, as shown in FIG. 1, in this embodiment, an inspection/judgment device (hereinafter referred to as IPU) 20 is used to determine whether or not the PCU 10 can be reused or not, while the PCU 10 is still installed in the hybrid vehicle 2. Inspect and determine whether or not it is necessary. From here on, the explanation will be made while also referring to FIGS. 3 and 4. FIG. 3 shows a flowchart illustrating an example of the inspection determination process of the IPU 20. FIG. 4 shows an explanatory diagram showing an example of rank determination.

The IPU 20 is a control device mainly equipped with a microcomputer, semiconductor memory such as RAM, ROM, or EEPROM, and an input/output interface. In this embodiment, the IPU 20 also includes a liquid crystal display that displays the progress status of the inspection determination process. A program (inspection determination program) that enables inspection determination processing to be described later is stored in advance in, for example, a ROM. Further, an inspection program and a new control program, which will be described later, are stored in advance in, for example, an EEPROM. The IPU 20 is connected, for example, to the PCU 10 via an in-vehicle LAN such as CAN or LIN, or to another controller (ECU) via a service connector 5 provided in the vehicle.

In this embodiment, the IPU 20 is configured to be able to obtain temperature data, voltage data, current data, etc. from the PCU 10 as data related to switching elements such as the power card 13, and also the cooling water temperature of the PCU 10 and the running speed of the hybrid vehicle 2. The controller is configured to be able to acquire vehicle status data (vehicle status information) such as the number of miles traveled, years of use (cumulative usage time), and self-diagnosis information from other controllers.

After the IPU 20 configured as described above is connected to the PCU 10 and the service connector 5 installed in the hybrid vehicle 2, the IPU 20 executes an inspection and determination process to check whether the PCU 10 can be reused and whether or not it needs to be replaced. and judge.

As shown in FIG. 3, in the inspection determination process by the IPU 20, first, in step S11, the control program (current control program) currently installed in the controller 19 of the PCU 10 is downloaded (uploaded) from the memory (for example, EEPROM) of the controller 19. ) and save processing is performed. This is because the current control program may be re-implemented (re-installed) in the controller 19 depending on the result of rank determination, which will be described later.

In the next step S12, a process of installing (installing) a program for inspecting the PCU 10 into the controller 19 is performed. This inspection program tests multiple switching elements so that, for example, voltage data, current data, and temperature data necessary for determining the thermal resistance of each switching element constituting the power cards 13, 15-17 can be obtained. The on/off operation is performed individually or in a predetermined combination. That is, in the test program, on/off control different from normal PWM control is performed on the switching elements of the power cards 13, 15-17.

In the subsequent step S13, a process is performed to acquire predetermined data from the PCU 10 operating according to such an inspection program. The predetermined data is, for example, device information of the power cards 13, 15-17. The device information is mainly voltage data, current data, and temperature data necessary to determine the degree of deterioration (eg, thermal resistance and on-resistance) of each switching element included in the power cards 13 and 15-17. The data that the inspection program acquires from the PCU 10 is data (for example, temperature data, voltage data, current data, etc.) necessary to determine the degree of deterioration of other semiconductor devices (for example, freewheeling diodes) included in the power card 13 etc. It may be.

In addition, in step S13, vehicle status information obtained via the service connector 5 of the hybrid vehicle 2 (cooling water temperature of the PCU 10, mileage of the hybrid vehicle 2, years of use, self-diagnosis information, etc.) is also included as predetermined data. from the controller (ECU). This makes it possible to determine the degree of deterioration of switching elements such as the power card 13, including parameters of deterioration over time, as will be described later.

In step S14, a process is performed to calculate the degree of deterioration of the PCU 10 based on the predetermined data (device information and vehicle status information) obtained in step S13. In this embodiment, the degree of deterioration of the PCU 10 is, for example, the degree of deterioration of the performance of switching elements included in the power cards 13 and 15-17. More specifically, it is the magnitude of the thermal resistance, on-resistance, etc. of each switching element included in the power cards 13, 15-17. Alternatively, the current value or the rate of increase in heat generation temperature during the on-operation of these switching elements may be used.

Further, the numerical value indicating the degree of deterioration of the PCU 10 may be the conversion efficiency, voltage-current characteristics, etc. that can be calculated from the ratio of the input power and output power of the PCU 10. Furthermore, the occurrence rate of failures due to passage narrowing or leakage of cooling water in the PCU cooler may be determined based on the temperature and amount of cooling water flowing through the PCU cooler (not shown).

In step S15, rank determination processing is performed. This process determines the state of performance deterioration of the PCU 10 and ranks it based on the degree of deterioration of the PCU 10 calculated in step S14 and the number of mileage or years of use (cumulative usage time) of the hybrid vehicle 2. do. That is, the rank is an index indicating the degree of deterioration of the PCU 10. In this embodiment, for example, the rankings are divided into three ranks, AC, based on the rank determination map shown in FIG. For example, the rank is determined from the plotted area based on the relationship between the thermal resistance value and the number of mileage (or number of years of use).

For example, even if the number of miles traveled (or the number of years of use) is relatively small, if the thermal resistance value of any switching element included in the power card 13, 15-17 is large, it is determined to be rank C (Fig. 4 ). On the other hand, even if the thermal resistance value of any of the switching elements of the power card 13, 15-17 is relatively large, if the number of miles traveled (or number of years of use) is large, it will be ranked A or B. It is determined (◎ mark and ○ mark shown in Fig. 4).

In addition, for example, the on-resistance of a switching element, the current value during on-operation, the rate of increase in heat generation temperature, the conversion efficiency and voltage-current characteristics that can be calculated from the ratio of input power and output power of the PCU 10, etc. As in the case, it is possible to determine the rank from the plotted area based on the relationship with the number of miles traveled (or years of use).

If the performance deterioration state of the PCU 10 is determined to be A rank by such rank determination processing (S15; A rank), the PCU 10 is the current state of the PCU 10 that was installed before the inspection with little progress in performance deterioration. Even if switching control of the power cards 13, 15-17 is performed using a control program, it is expected that the remaining lifespan will be long. Therefore, after selecting the current control program in step S16 as the control program to be reinstalled, the current control program is reinstalled in the controller 19 in the subsequent step S18.

On the other hand, if the state of performance deterioration of the PCU 10 is determined to be rank B by the rank determination process (S15; rank B), the performance deterioration of the relevant PCU 10 has progressed to a considerable extent, but the output of the PCU 10 is It is expected that there is still some remaining life with limited switching control. Therefore, after selecting a new control program (new control program) with output limitations for the PCU 10 in step S17 as the control program to be installed, the new control program is installed in the controller 19 in the subsequent step S18.

When the current control program or the new control program is installed in the controller 19 in step S18, a message such as "Reusable" can be displayed on the liquid crystal display to inform the operator that the PCU 10 can be reused. (Illustrated) is displayed. This notifies the operator that the PCU 10 can be reused and that there is no need to replace the PCU 10.

On the other hand, if the rank determination process determines that the state of performance deterioration of the PCU 10 is C rank (S15; C rank), the performance of the PCU 10 has deteriorated to such an extent that it cannot be used in the future. is progressing, and even if switching control that can limit the output of the PCU 10 is performed, it is expected that there will be almost no remaining life.

In such a case, in step S20, for example, a message such as "Reuse is not allowed" that can inform the operator that reuse of the PCU 10 is not possible is displayed on the liquid crystal display (not shown) in a conspicuous font color. Display processing is performed. A warning sound may also be output. This notifies the operator that the PCU 10 cannot be reused and needs to be replaced.

When the series of processes described above are completed, the IPU 20 turns off the power to the PCU 10 and ends the main inspection determination process. In this way, the IPU 20 of this embodiment makes it possible to determine whether or not the PCU 10 needs to be reused or replaced while the PCU 10 is installed in the hybrid vehicle 2, so that the PCU 10 can be reused or its life extended at low cost. It can be realized.

As described above, in the PCU 10 reuse system of this embodiment, the IPU 20 replaces the current control program installed in the PCU 10 with the inspection program (S12), and the power cards 13 and 15 of the PCU 10 that operate under the control of the inspection program -17 operating data is acquired (S13). Then, the degree of deterioration of the PCU 10 is determined based on the operating data, and a rank indicating the degree of deterioration is determined (S15). In accordance with the determined rank, the IPU 20 installs another control program in the PCU 10 instead of the inspection program that can extend the remaining life of the PCU 10 compared to the case of controlling with the current control program (S17, S18).

As a result, the remaining life of the PCU 10 can be extended by performing work that can be performed at a maintenance site, such as replacing the current control program that was previously installed with another control program. Therefore, for example, it is possible to extend the usable time of the PCU 10 without replacing the power cards 13, 15-17, which tend to affect the life of the PCU 10. Further, such work can be performed in a relatively short time because it can be performed without removing the PCU 10 from the hybrid vehicle 2. Therefore, it becomes possible to reuse and extend the life of the PCU 10 at low cost.

In this embodiment, an example has been described in which the functions of both the inspection device and the determination device are realized by the IPU 20, but these may be configured by separate hardware. For example, the function of the inspection device may be assigned to the controller 19 of the PCU 10, and the determination software may be installed in a general-purpose personal computer (hereinafter simply referred to as a personal computer) to configure the determination device. In this case, the PCU 10 includes, for example, a program for realizing the functions of the inspection device separately from a control program for controlling the voltage converter 12 and the inverter 14. Further, for example, another control program for extending the remaining life of the PCU 10 is included in the personal computer, and is installed in the controller 19 from the personal computer.

Furthermore, for example, the inspection device may be configured with a dedicated board having a CPU, memory, DSP, etc., and this dedicated board may be installed in a personal computer in which determination software is installed to configure an IPU 20 equivalent. Furthermore, for example, an inspection apparatus may be constructed by installing inspection software on a personal computer, and may be configured such that data during operation can be sent from the personal computer to a determination server having the function of a determination apparatus. The personal computer and the determination server are connected to the Internet, for example, via a wired LAN, wireless LAN, or ISP.

Points to note regarding the example technology will be described. The PCU 10 corresponds to an example of a power conversion device. The IPU 20 corresponds to an example of an inspection device and a determination device. The power cards 13, 15-17 (the switching elements they have) correspond to an example of a semiconductor device for power conversion. The hybrid vehicle 2 corresponds to an example of a vehicle.

Although specific examples of the present invention have been described in detail above, these are merely illustrative and do not limit the scope of the claims. The techniques described in the claims include various modifications and changes to the specific examples illustrated above. Further, the technical elements described in this specification or the drawings exhibit technical usefulness singly or in various combinations, and are not limited to the combinations described in the claims as filed. Further, the techniques illustrated in this specification or the drawings simultaneously achieve multiple objectives, and achieving one of the objectives has technical utility in itself.

2: Hybrid vehicle 3: Main battery 5: Service connector 6: Engine 7: Motor 10: PCU 12: Voltage converter 13, 15-17: Power card 14: Inverter 19: Controller 20: IPU

Claims (2)

an inspection device that replaces a current control program installed in the power conversion device with an inspection program and acquires data during operation of the power conversion device that operates under the control of the inspection program;
a determination device that determines the degree of deterioration of the power conversion device based on the operating data and outputs a rank indicating the degree of deterioration to the inspection device;
The inspection device implements, in place of the inspection program, another control program on the power conversion device that extends the remaining life of the power conversion device compared to the case where the power conversion device is controlled using the current control program, depending on the rank. ,
A power converter reuse system characterized by the following. 2. The power conversion device reuse system according to claim 1, wherein the operating data is data regarding a power conversion semiconductor device included in the power conversion device.

Images