JP2012161168A - Device for determining element lifetime - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately determine the lifetime of switching elements of an inverter stored in a storage of an electric vehicle.SOLUTION: An environmental temperature difference ΔTest(j) when calculating an estimated element temperature Tsest(j) in a destination by subtracting the environmental temperature difference ΔTest(j) from a test element temperature Tstmp is calculated as the sum of two products: the product of a first sensitivity αa reflecting the ratio of the variation of a room temperature Ta to the variation of an ambient temperature Tz when running in a predetermined running pattern under a plurality of environmental temperatures and a temperature difference ΔT(j) obtained by subtracting a highest temperature in the destination from a test environmental temperature Tstmp and the product of a second sensitivity αw reflecting the ratio of the variation of a cooling water temperature Tw to the variation of the ambient temperature Tz and the temperature difference ΔT(j) (S140). As a result, the estimated element temperature Tsest(j) in the destination can be calculated more appropriately.

Description

  The present invention relates to an element life determination device, and more specifically, an electric motor that can output power for traveling, an inverter that drives an electric motor by switching of a switching element that is cooled by a cooling liquid, and the electric motor and electric power via the inverter. The present invention relates to an element life determination apparatus that determines the life of a switching element of an electric vehicle including a battery capable of exchange.

  Conventionally, as this kind of element life determination device, in the inverter device of the automobile that runs by supplying the power of the DC power source to the motor by turning on and off the power transistor of the inverter device and driving the engine, the life of the power transistor is reduced. What is determined has been proposed (see, for example, Patent Document 1). In this device, before driving the vehicle, the power transistor of the inverter is driven so as to supply a current of a predetermined value to the motor for a predetermined period, the thermal resistance value of the power transistor at this time is calculated, and the calculated thermal resistance The lifetime of the power transistor is determined based on the value.

Japanese Patent Laid-Open No. 2003-9541

  As one of the methods for determining the life of a power transistor element included in an inverter mounted on an electric vehicle before shipping to a destination, the element temperature when the vehicle travels in a predetermined traveling pattern under a relatively high test environment temperature. The actual element temperature at the destination is estimated by subtracting the temperature difference between the test environment temperature and the maximum temperature at the destination from the element temperature obtained through experiments. Some devices determine the lifetime of an element based on the element temperature. However, in consideration of the fact that the outside temperature as the environmental temperature may not be reflected as it is in the engine room that houses the inverter during driving, this method estimates that the element temperature at the destination is lower than the actual temperature. Therefore, there is a possibility that the lifetime of the element cannot be properly determined.

  The main object of the element lifetime determination apparatus of the present invention is to more appropriately determine the lifetime of the switching element of the inverter stored in the storage section of the electric vehicle.

  The element lifetime determination apparatus of the present invention employs the following means in order to achieve the main object described above.

The device lifetime determination apparatus of the present invention is
An electric motor housed in a housing part at the front of the vehicle and capable of outputting driving power; an inverter housed in the housing part that drives the motor by switching of a switching element cooled by a coolant; A test element that acquires a test element temperature that is a maximum temperature of the switching element when an electric vehicle including the electric motor and a battery capable of exchanging electric power travels in a predetermined traveling pattern under a predetermined test environment temperature Estimating a destination element temperature by subtracting an environmental temperature difference based on a temperature difference obtained by subtracting a maximum temperature at a destination of the electric vehicle from the predetermined test environment temperature from the acquired test element temperature. Destination element temperature estimating means for determining the life of the switching element based on the estimated destination element temperature And element lifetime determination means, the element life determining apparatus comprising,
The environmental temperature difference is the storage with respect to the amount of change in the environmental temperature obtained from the relationship between the environmental temperature and the temperature in the storage portion when the electric vehicle travels in the predetermined traveling pattern under a plurality of environmental temperatures. The product of the first sensitivity reflecting the rate of change in temperature in the section and the temperature difference, the environmental temperature when the electric vehicle travels in the predetermined traveling pattern under the plurality of environmental temperatures, and the The sum of the product of the second sensitivity and the temperature difference reflecting the ratio of the amount of change in the temperature of the coolant to the amount of change in the environmental temperature obtained from the relationship with the temperature of the coolant.
It is characterized by that.

  In the element lifetime determination apparatus of the present invention, the environmental temperature difference when estimating the destination element temperature by subtracting the environmental temperature difference from the test element temperature is such that the electric vehicle travels in a predetermined traveling pattern under a plurality of environmental temperatures. From the first sensitivity and the predetermined test environment temperature that reflects the ratio of the change in the temperature in the storage unit housing the inverter to the change in the environmental temperature obtained from the relationship between the ambient temperature and the temperature in the storage unit The product of the temperature difference obtained by reducing the maximum temperature of the destination of the vehicle, the environmental temperature when the electric vehicle travels in a predetermined traveling pattern under a plurality of environmental temperatures, and the temperature of the coolant that cools the switching element The sum of the product of the second sensitivity and the temperature difference reflecting the ratio of the change amount of the coolant temperature to the change amount of the environmental temperature obtained from the relationship. Therefore, the environment temperature difference is calculated by correcting the temperature difference between the predetermined test environment temperature and the maximum temperature of the destination of the electric vehicle using the first sensitivity and the second sensitivity. The temperature difference can reflect the degree of change in temperature in the storage unit with respect to change in environmental temperature and the degree of change in temperature of the coolant. Thereby, an environmental temperature difference can be calculated more appropriately, and a destination element temperature can be estimated more appropriately. As a result, the life of the switching element of the inverter can be determined more appropriately.

It is a block diagram which shows the outline of a structure of the hybrid vehicle 20 containing the determination object of the element lifetime determination apparatus as one Example of this invention. It is explanatory drawing explaining a mode that the apparatus required for driving | running | working was stored in the engine room. FIG. 3 is a configuration diagram showing an outline of the configuration of inverters 41 and 42; It is a flowchart which shows an example of the element lifetime determination process performed by ECU100 outside a vehicle. It is explanatory drawing which shows an example of a mode which calculates temperature difference (DELTA) T (j) from test environment temperature Tetmp, and an example of estimated element temperature Tsest (j) calculated in the prior art example. It is explanatory drawing which shows an example of the temperature distribution of the estimation element temperature Tsest (j) of each month when it drive | works with a predetermined driving | running | working pattern in a prior art example. It is explanatory drawing which shows an example of the temperature distribution obtained by converting the temperature distribution of the presumed element temperature Tsest (j) of FIG. It is explanatory drawing explaining an example of a mode that 1st sensitivity (alpha) a is set. It is explanatory drawing explaining an example of a mode that 2nd sensitivity (alpha) w is set.

  Next, the form for implementing this invention is demonstrated using an Example.

  FIG. 1 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 20 including a determination target of an element lifetime determination apparatus as an embodiment of the present invention. FIG. It is explanatory drawing explaining a mode stored in the room 21, and FIG. 3 is a block diagram which shows the outline of a structure of the inverters 41 and 42. As shown in FIG. As shown in FIG. 1, the hybrid vehicle 20 of the embodiment includes an engine 22 configured as an internal combustion engine using gasoline or light oil as a fuel, and an engine electronic control unit (hereinafter referred to as an engine ECU) that controls the operation of the engine 22. 24), a planetary gear 30 in which a carrier is connected to the crankshaft 26 of the engine 22 and a ring gear is connected to a drive shaft 32 connected to drive wheels 63a and 63b via a differential gear 62, for example, a synchronous generator motor For example, a motor MG1 whose rotor is connected to the sun gear of the planetary gear 30, a motor MG2 which is configured as a synchronous generator motor and whose rotor is connected to the drive shaft 32, and for driving the motors MG1 and MG2. Drives inverters 41 and 42 and motors MG1 and MG2. A motor electronic control unit (hereinafter referred to as a motor ECU) 40 to be controlled, a battery 50 configured as, for example, a lithium ion secondary battery and exchanging electric power with the motors MG1 and MG2 via inverters 41 and 42, and the entire vehicle And a hybrid electronic control unit (hereinafter referred to as a hybrid ECU) 70 to be controlled. As shown in FIG. 2, the engine room 21 at the front of the vehicle includes an engine 22, a planetary gear 30 and motors MG1 and MG2 housed in a case 31, and inverters 41 and 42 housed in a case 49. A battery 50 is stored behind the rear seat (not shown) at the rear of the vehicle.

  As shown in FIG. 3, the inverters 41 and 42 include transistors T11 to T16 and T21 to 26 as six switching elements, and six diodes D11 to D12 connected in parallel to the transistors T11 to T16 and T21 to T26 in the reverse direction. D16 and D21 to D26. Hereinafter, the transistors T11 to T16 and T21 to T26 are collectively referred to as T1 and T2, respectively.

  The engine ECU 24 controls the operation of the engine 22 by inputting signals from various sensors that detect the state of the engine 22, such as a signal from a crank position sensor (not shown) attached to the crankshaft 26 of the engine 22. The motor ECU 40 is attached to a cooling system 44 that cools the element temperature Ts from the temperature sensor 43 that detects the temperature of the transistor T2 of the inverter 42 and the transistors T1 and T2 of the inverters 41 and 42 by circulation of cooling water. Signals from various sensors for detecting the states of the motors MG1 and MG2 and the inverters 41 and 42, such as the cooling water temperature Tw from the water temperature sensor 45 for detecting the temperature of the water, and the transistor T1 as a switching element of the inverters 41 and 42 are input. , T2 to control the driving of the motors MG1, MG2.

  The hybrid ECU 70 is configured as a microprocessor centered on the CPU 72, and in addition to the CPU 72, a ROM 74 that stores a processing program, a RAM 76 that temporarily stores data, and a nonvolatile flash memory that holds the stored data. 78, and an input / output port and a communication port (not shown). The hybrid ECU 70 includes an ignition signal from the ignition switch 80, a shift position SP from the shift position sensor 82 that detects the operation position of the shift lever, and an accelerator opening Acc from the accelerator pedal position sensor 84 that detects the amount of depression of the accelerator pedal. , The brake pedal position BP from the brake pedal position sensor 86 that detects the depression amount of the brake pedal, the vehicle speed V from the vehicle speed sensor 88, the outside air temperature Tz from the outside air temperature sensor 90 that detects the temperature around the vehicle, and the inside of the engine room 21 The room temperature Ta from the temperature sensor 92 that detects the ambient temperature, signals from various sensors that detect the state of the battery 50, and the like are input via the input port. The hybrid electronic control unit 70 is connected to the engine ECU 24 and the motor ECU 40 via a communication port, and exchanges various control signals and data with the engine ECU 24 and the motor ECU 40. Further, the hybrid ECU 70 can be connected to an electronic control unit (hereinafter referred to as an outside-vehicle ECU) 100 outside the vehicle by communication as necessary, and is stored in the flash memory 78 when the outside ECU 100 is connected when the system is stopped. The information can be output to the ECU 100 outside the vehicle by communication.

  The hybrid vehicle 20 of the embodiment configured as described above calculates a required torque to be output to the drive shaft 32 based on the accelerator opening Acc and the vehicle speed V corresponding to the depression amount of the accelerator pedal by the driver, and this required torque. The engine 22, the motor MG 1, and the motor MG 2 are controlled to be operated so that the required power corresponding to is output to the drive shaft 32. As the operation control of the engine 22, the motor MG1, and the motor MG2, the operation of the engine 22 is controlled so that power corresponding to the required power is output from the engine 22, and all of the power output from the engine 22 is transmitted to the planetary gear 30 and the motor MG1. And a motor MG2 to convert the torque and output to the drive shaft 32. The torque conversion operation mode for driving and controlling the motor MG1 and the motor MG2, and the power suitable for the sum of the required power and the power required for charging and discharging the battery 50 Is controlled so that the engine 22 is output from the engine 22, and all or a part of the power output from the engine 22 with charging / discharging of the battery 50 is converted by the planetary gear 30, the motor MG1, and the motor MG2. So that the required power is output to the drive shaft 32. Charge-discharge drive mode for driving and controlling over data MG1 and the motor MG2, there is a motor operation mode in which operation control to output a power commensurate to stop the operation of the engine 22 to the required power from the motor MG2 to the drive shaft 32.

  Next, an operation related to the hybrid vehicle 20 of the embodiment configured as described above, particularly an operation when determining the lifetime of the transistor T2 of the inverter 42 will be described. FIG. 4 is a flowchart showing an example of the element life determination process executed by the ECU 100 outside the vehicle. This process is executed when the hybrid ECU 70 and the outside ECU 100 are connected when the system is stopped before the vehicle is shipped.

  In the element life determination process, the CPU (not shown) of the outside ECU 100 first performs the predetermined travel of the hybrid vehicle 20 in a state where the test environment temperature Tempmp (for example, 40 ° C.) set in advance as a relatively high temperature is set to the ambient temperature. A test element temperature Tstmp, which is the temperature of the transistor T2 when traveling in a pattern, is acquired (step S100). In the embodiment, the vehicle travels using a traveling test facility that can adjust the temperature around the vehicle. In addition, in the embodiment, the predetermined traveling pattern is a pattern in which 24 hours per day are divided into a time for traveling once in each of the first to fourth traveling patterns and a time for non-starting when the system is stopped. It was supposed to be used. In the embodiment, the element temperature Tstmp is acquired by using the maximum temperature for each pattern of the element temperature Ts detected by the temperature sensor 43 during traveling in the first to fourth traveling patterns as the test element temperatures Tstmp1 to Tstmp1. The information stored in the flash memory 78 of the hybrid ECU 70 as Tstmp4 and the non-startup (system stop) test element temperature Tstmp5 stored in the flash memory 78 as the same temperature as the test environment temperature Ttmp are input by communication. I decided to do it. The test element temperature Tstmp is used as a collective expression of the test element temperatures Tstmp1 to Tstmp5 for convenience of explanation.

  Subsequently, the maximum temperature of each month at the destination of the vehicle is subtracted from the test environment temperature Ttmp to calculate a temperature difference ΔT (j) (variable j is an integer of value 1 to value 12, the same applies hereinafter) (step) S110). FIG. 5 shows an example of how the temperature difference ΔT (j) is calculated from the test environment temperature Ttmp and an example of the estimated element temperature Tsest (j) calculated in the conventional example. As shown in the figure, when the test environment temperature Ttmp is 40 ° C. (refer to the thick solid line frame) and the highest temperature in January of the destination is 18 ° C., the temperature difference ΔT (1) is calculated as 22 ° C. When the maximum temperature in February of the ground is 21 ° C., ΔT (2) is similarly calculated as 19 ° C. Further, when the conventional calculation method in which the temperature difference ΔT (j) calculated in this way is directly subtracted from the test element temperature Tstmp acquired in step S100 is used, the transistor T2 for each month at the destination in the conventional example is estimated. The estimated element temperature Tsest (j) which is the maximum temperature can be calculated. Hereinafter, the description of the element life determination process of the embodiment will be interrupted, and the element life determination process of the conventional example will be described. Note that in the flowchart of the element lifetime determination process of the embodiment of FIG. 4, the process is the same as that of the embodiment and the conventional example except for the processes of steps S <b> 120 to S <b> 150. To do.

  In the element lifetime determination process of the conventional example, the estimated element temperatures Tsest1 (j) to Tsest5 (j) at the destination are obtained by subtracting the monthly temperature difference ΔT (j) from the test element temperatures Tstmp1 to Tstmp5 acquired in step S100. Is calculated. In the example of FIG. 5, since the test element temperatures Tstmp1 to Tstmp5 are 90 ° C., 95 ° C., 80 ° C., 100 ° C., 40 ° C. (see the inside of the broken line frame), the temperature difference ΔT (1) in January is 22 ° C. The estimated element temperatures Tsest1 (1) to Tsest5 (1) for January are calculated as 68 ° C, 73 ° C, 58 ° C, 78 ° C, and 18 ° C. Similarly, the estimated element temperatures Tsest1 (2) to Tsest5 (2) in February are calculated by subtracting the temperature difference ΔT (2) (= 19 ° C.) from the test element temperatures Tstmp1 to Tstmp5. The estimated element temperature Tsest (j) is used as a collective expression of the estimated element temperatures Tsest1 (j) to Tsest5 (j) for convenience of explanation.

  When the estimated element temperature Tsest (j) is calculated in this way, based on the calculated estimated element temperature Tsest (j) of each month, a predetermined expected usage year Y (for example, a predetermined running pattern while traveling one day) (for example, The temperature distribution of the temperature of the transistor T2 when the vehicle is used for 10 years or 15 years is acquired (step S160). FIG. 6 shows an example of the temperature distribution of the estimated element temperature Tsest (j) for each month when the vehicle travels in a predetermined traveling pattern in the conventional example, and FIG. 7 shows the temperature distribution of the estimated element temperature Tsest (j) of FIG. An example of the temperature distribution obtained by converting into the number of hours for the expected years of use Y is shown. In the embodiment, as shown in FIG. 6, the estimated element temperature Tsest1 (j) to Tsest5 (j) of each month including the non-starting time is set to any number of the temperature classes every 5 ° C. By counting whether it corresponds, the temperature distribution by the frequency | count of the pertinent month per year of presumed element temperature Tsest (j) is first obtained. For example, when the non-start-up in the example of FIG. 5 is seen, the temperature becomes 15 ° C. or more and less than 20 ° C. twice in January and December (see the inside of the circle in FIG. 5). Two times are recorded in the temperature section of 15 ° C. or more and less than 20 ° C. at the time of start-up (see the inside of the circle in FIG. 6). Then, as shown in FIG. 7, the temperature distribution of FIG. 6 is converted into the number of hours for one year for each running pattern including the time of non-starting (see the upper row in the figure), and the total number of hours for each temperature category Obtain the estimated usage time for Y years by further multiplying the expected usage years Y (see the lower part of the figure), and the temperature distribution according to the number of hours of the transistor T2 when the vehicle is used over the expected usage years Y It was supposed to be acquired.

  Thus, when the temperature distribution according to the number of hours of the transistor T2 when the vehicle is used over the planned usage year Y is acquired, the data of the planned usage time for Y years (the lowermost data in FIG. 6) in this temperature distribution is obtained in advance. Using the conversion factor obtained by experiment for each temperature category, the usage time at the heat-resistant temperature (for example, 120 ° C. or 140 ° C.) as the rated value of the transistor T2 is converted (step S170), and the converted usage Whether the transistor T2 can sufficiently withstand the usage for the expected number of years Y by comparing the total time with the service life (eg, several thousand hours) as the rated value of the transistor T2 or a smaller time threshold The determination, that is, the lifetime of the transistor T2 is determined (step S180), and the element lifetime determination process is terminated. The element lifetime determination process of the conventional example has been described above.

  Returning to the description of the element lifetime determination process of the embodiment. In the conventional example, when calculating the estimated element temperature Tsest (j) at the destination, a calculation method is used in which the temperature difference ΔT (j) calculated in step S110 is directly reduced from the test element temperature Tstmp acquired in step S100. However, in this method, in consideration of the possibility that the element temperature at the destination is estimated to be lower than the actual temperature, in the embodiment, a different method is adopted as follows. In the embodiment, when the temperature difference ΔT (j) for each month is calculated, the outside air temperature Tz from the outside air temperature sensor 90 when the vehicle travels according to a predetermined traveling pattern in a state where the environmental temperature of the vehicle is set to a plurality of different temperatures. The relationship between the temperature sensor 92 and the room temperature Ta is obtained as a function by collecting a plurality of sets of data stored in the flash memory 78, and the room temperature Ta relative to the amount of change in the outside temperature Tz is obtained from the function thus obtained. The first sensitivity αa that reflects the ratio of the change amount is set (step S120). FIG. 8 shows an example of how the first sensitivity αa is set. As shown in the figure, in the embodiment, the ratio obtained by multiplying the ratio (slope) of the temperature change amount ΔTa of the room temperature Ta to the temperature change amount ΔTza of the outside air temperature Tz in the entire obtained function by the value 0.5 is the first. The sensitivity αa was set. Since the same unit is used for the outside temperature Tz and the room temperature Ta, the first sensitivity αa is a positive value less than 0.5. The reason for multiplying by 0.5 will be described next. Moreover, you may obtain | require 1st sensitivity (alpha) a as a different ratio (slope) for several temperature divisions.

  Subsequently, when setting the first sensitivity αa, the same driving as that for collecting a plurality of data, that is, when driving according to a predetermined driving pattern in a state where the environmental temperature of the vehicle is set to a plurality of different temperatures. The relationship between the outside air temperature Tz from the outside air temperature sensor 90 and the cooling water temperature Tw from the water temperature sensor 45 (the same unit as the outside air temperature Tz) is obtained as a function by collecting a plurality of data sets stored in the flash memory 78. Thus, the second sensitivity αa that reflects the ratio of the change amount of the cooling water temperature Tw to the change amount of the outside air temperature Tz is set from the function thus obtained (step S130). FIG. 9 shows an example of how the second sensitivity αw is set. As in the example of FIG. 8, in the example, the ratio (slope) of the temperature change amount ΔTw of the cooling water temperature Tw to the temperature change amount ΔTzw of the outside air temperature Tz in the entire function is multiplied by the value 0.5. The second sensitivity αw was set. In this way, when the first sensitivity αa and the second sensitivity αw are set, the value 0.5 is multiplied because the room temperature Ta and the cooling water temperature Tw affect the estimated environmental temperature difference ΔTest (j) described below. This is because the ratio to be made is 1: 1. Therefore, depending on the vehicle, when the first sensitivity αa is obtained, the value 0.6 may be multiplied, and when the second sensitivity αw is obtained, the value 0.4 may be multiplied. The second sensitivity αw may also be obtained as a different ratio (gradient) for each of a plurality of temperature sections.

  When the first sensitivity αa and the second sensitivity αw are thus set, the temperature difference ΔT (j) is calculated by the following equation (1) using the set first sensitivity αa, second sensitivity αw, and temperature difference ΔT (j). The estimated environmental temperature difference ΔTest (j) obtained by the correction is calculated (step S140), and the estimated element at the destination is obtained by subtracting the estimated environmental temperature difference ΔTest (j) from the test element temperature Tstmp obtained in step S100. The temperature is calculated as Tsest (j) (step S150). Therefore, the temperature difference ΔT (j) can be corrected so that the first sensitivity αa reflects the degree of change in the room temperature Ta with respect to the outside air temperature Tz, and the cooling water temperature Tw with respect to the outside air temperature Tz can be corrected by the second sensitivity αw. The temperature difference ΔT (j) can be corrected so as to reflect the degree of change. Thereby, the estimated element temperature Tsest (j) at the destination is compared with the conventional example in which the estimated element temperature Tsest (j) at the destination is calculated by subtracting the temperature difference ΔT (j) from the test element temperature Tstmp. Can be calculated more appropriately.

  ΔTest (j) = αa ・ ΔT (j) + αw ・ ΔT (j) (1)

  When the estimated environmental temperature difference ΔTest (j) is calculated in this way, as in the conventional example, the vehicle travels for one day with a predetermined traveling pattern based on the estimated element temperature Tsest (j) of each month over the estimated usage year Y. The temperature distribution of the transistor T2 when the vehicle is used is acquired (step S160), and the data on the expected usage time for Y years in this temperature distribution is converted into the usage time at the heat-resistant temperature as the rated value of the transistor T2, respectively. At the same time (step S170), the lifetime of the transistor T2 is determined by comparing the total of the converted usage time with the withstand time as the rated value of the transistor T2 (step S180), and the lifetime determination process is terminated. . By such processing, in the embodiment, the lifetime of the transistor T2 of the inverter 42 can be more appropriately determined.

  According to the element lifetime determination apparatus that determines the lifetime of the transistor T2 of the inverter 42 provided in the hybrid vehicle 20 of the embodiment described above, the estimation at the destination is performed by subtracting the environmental temperature difference ΔTest (j) from the test element temperature Tstmp. The environmental temperature difference ΔTest (j) when calculating the element temperature Tsest (j) is the ambient temperature Tz as the environmental temperature when the hybrid vehicle 20 travels in a predetermined traveling pattern under a plurality of environmental temperatures, and the engine room 21. Obtained by subtracting the maximum temperature of the destination from the first sensitivity αa, which reflects the ratio of the amount of change in the room temperature Ta to the amount of change in the outside temperature Tz obtained from the relationship with the room temperature Ta in the room, and the test environment temperature Tstmp Product of the temperature difference ΔT (j) and the hybrid vehicle 20 in a predetermined traveling pattern under a plurality of environmental temperatures. The second sensitivity αw reflecting the ratio of the change amount of the cooling water temperature Tw to the change amount of the outside air temperature Tz obtained from the relationship between the outside air temperature Tz as the environmental temperature when the operation is performed and the cooling water temperature Tw of the transistor T2, and the temperature difference Since it is calculated as the sum of the product of ΔT (j), the estimated element temperature Tsest (j) at the destination can be calculated more appropriately. As a result, the lifetime of the transistor T2 of the inverter 42 can be determined more appropriately. The life of the transistor T1 of the inverter 41 can be determined in the same manner.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. In the embodiment, the motor MG2 corresponds to an “electric motor”, the inverter 42 corresponds to an “inverter”, the battery 50 corresponds to a “battery”, the hybrid vehicle 20 corresponds to an “electric vehicle”, and the hybrid vehicle 20 The vehicle ECU 100 that stores the test element temperature Tstmp, which is the maximum temperature of the transistor T2 when traveling in a predetermined travel pattern under the test environment temperature Ttmp, executes the process of step S100 of the element life determination process of FIG. The hybrid ECU 70 that outputs data to the outside ECU 100 corresponds to a “test element temperature acquisition means”, and an environmental temperature difference based on a temperature difference ΔT (j) obtained by subtracting the maximum temperature at the destination of the vehicle from the test environment temperature Ttmp. At the destination by subtracting ΔTempp (j) from the test element temperature Tstmp When the processing of steps S110 to S150 of the element lifetime determination process of FIG. 4 for calculating the estimated element temperature Tsest (j) of FIG. 4 is performed, the estimated environmental temperature difference ΔTest (j) The ratio of the amount of change in the room temperature Ta to the amount of change in the outside temperature Tz obtained from the relationship between the outside temperature Tz as the environmental temperature and the room temperature Ta in the engine room 21 when the vehicle travels in a predetermined travel pattern is reflected. Between the product of the first sensitivity αa and the temperature difference ΔT (j), and the ambient temperature Tz and the cooling water temperature Tw as the environmental temperature when the hybrid vehicle 20 travels in a predetermined traveling pattern under a plurality of environmental temperatures. Calculated as the sum of the product of the second sensitivity αw and the temperature difference ΔT (j) reflecting the ratio of the change amount of the cooling water temperature Tw to the change amount of the outside air temperature Tz obtained from The ECU 100 and the hybrid ECU 70 that outputs the stored data to the outside ECU 100 correspond to a “destination element temperature estimation means”. Based on the calculated estimated element temperature Tsest (j), the temperature distribution is acquired and used at the heat resistant temperature. The vehicle exterior ECU 100 that executes steps S160 to S180 of the element life determination process of FIG. 4 for determining the life of the transistor T2 by conversion to time or the like corresponds to “element life determination means”.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem is the same as that of the embodiment described in the column of means for solving the problem. Therefore, the elements of the invention described in the column of means for solving the problems are not limited. That is, the interpretation of the invention described in the column of means for solving the problems should be made based on the description of the column, and the examples are those of the invention described in the column of means for solving the problems. It is only a specific example.

  As mentioned above, although the form for implementing this invention was demonstrated using the Example, this invention is not limited at all to such an Example, In the range which does not deviate from the summary of this invention, it is with various forms. Of course, it can be implemented.

  The present invention can be used in the manufacturing industry of electric vehicles and element life determination devices.

  20 Hybrid Vehicle, 21 Engine Room, 22 Engine, 24 Electronic Control Unit for Engine (Engine ECU), 26 Crankshaft, 30 Planetary Gear, 31 Case, 32 Drive Shaft, 40 Electronic Control Unit for Motor (Motor ECU), 41, 42 Inverter, 43 Temperature sensor, 44 Cooling system, 45 Water temperature sensor, 49 Case, 50 Battery, 62 Differential gear, 63a, 63b Driving wheel, 70 Hybrid electronic control unit (hybrid ECU), 72 CPU, 74 ROM, 76 RAM, 78 flash memory, 80 ignition switch, 82 shift position sensor, 84 accelerator pedal position sensor, 86 brake pedal position sensor, 88 vehicle speed sensor, 90 outside air Sensor, 92 a temperature sensor, 100 an electronic control unit (outside ECU), D11-D16, D21-D26 diode, T11 to T16, T21～T26 transistor, MG1, MG2 motor.

Claims (1)

An electric motor housed in a housing part at the front of the vehicle and capable of outputting driving power; an inverter housed in the housing part that drives the motor by switching of a switching element cooled by a coolant; A test element that acquires a test element temperature that is a maximum temperature of the switching element when an electric vehicle including the electric motor and a battery capable of exchanging electric power travels in a predetermined traveling pattern under a predetermined test environment temperature Estimating a destination element temperature by subtracting an environmental temperature difference based on a temperature difference obtained by subtracting a maximum temperature at a destination of the electric vehicle from the predetermined test environment temperature from the acquired test element temperature. Destination element temperature estimating means for determining the life of the switching element based on the estimated destination element temperature And element lifetime determination means, the element life determining apparatus comprising,
The environmental temperature difference is the storage with respect to the amount of change in the environmental temperature obtained from the relationship between the environmental temperature and the temperature in the storage portion when the electric vehicle travels in the predetermined traveling pattern under a plurality of environmental temperatures. The product of the first sensitivity reflecting the rate of change in temperature in the section and the temperature difference, the environmental temperature when the electric vehicle travels in the predetermined traveling pattern under the plurality of environmental temperatures, and the The sum of the product of the second sensitivity and the temperature difference reflecting the ratio of the amount of change in the temperature of the coolant to the amount of change in the environmental temperature obtained from the relationship with the temperature of the coolant.
A device life determination apparatus characterized by the above.

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