JP2023016581A - In-vehicle controller - Google Patents

Abstract

To suppress shortening of the life of a specific converter.SOLUTION: In an in-vehicle controller connected in parallel between two power lines and equipped in a vehicle along with a plurality of converters for converting the voltage between the two power lines to control a plurality of converters by a voltage command. On the basis of the ratio of heat strengths of a plurality of converters as the strengths to heat of the converters and the priority of a plurality of converters in a previous trip, the current trip order is set as the priority of a plurality of converters in a current trip is set, and the voltage command of a plurality of converters is set on the basis of the set current trip order.SELECTED DRAWING: Figure 5

Description

TECHNICAL FIELD The present invention relates to an in-vehicle control device, and more specifically, it is mounted in a vehicle together with a plurality of converters connected in parallel to two power lines and converts voltage between the two power lines, and controls the plurality of converters using a voltage command. The present invention relates to an in-vehicle control device for controlling.

Conventionally, this type of in-vehicle control device is mounted in a vehicle together with first and second converters (boost converters) that are connected in parallel to two power lines (power lines) and change the voltage between the two power lines. , first and second converters have been proposed (see Patent Document 1, for example). This device calculates a first stress value quantitatively indicating the stress accumulated in the first converter and a second stress value quantitatively indicating the stress accumulated in the second converter. Then, when the calculated first stress value is greater than the second stress value, the second converter is subjected to voltage control for controlling the voltage of the power line connected to the electric load, out of the two power lines, to be the target voltage. to run. As for the first converter, when the second converter cannot meet the required power required by the load, power control is performed so that part of the required power is used as the target power to supply power to the load. Such control suppresses uneven degradation between the two converters.

JP 2017-093144 A

By the way, in recent years, such an in-vehicle control device has been installed in a vehicle together with a plurality of converters connected in parallel to two power lines to convert voltage between the two power lines, and controls the plurality of converters using a voltage command. something is proposed. In the control of such a plurality of converters, if a certain converter is overloaded, the life of that converter will be shortened, and even if the other converters have a long life, the operation may be hindered. Therefore, it is desired to suppress the shortening of the life of a specific converter.

A main object of the in-vehicle control device of the present invention is to prevent the life of a specific converter from being shortened.

The in-vehicle control device of the present invention employs the following means to achieve the above main object.

A first in-vehicle control device of the present invention includes:
An in-vehicle control device that is mounted on a vehicle together with a plurality of converters that are connected in parallel to two power lines and convert voltage between the two power lines, and that controls the plurality of converters using a voltage command,
Based on the ratio of thermal strength as strength to heat of the converters and the priority of the converters on the previous trip, the current priority of the converters on the current trip. The gist is to set a trip order and set the voltage commands for the plurality of converters based on the set current trip order.

In the first vehicle-mounted control device of the present invention, based on the ratio of thermal strength as strength against heat of the plurality of converters and the priority of the plurality of converters on the previous trip, A current trip order is set as the priority of the plurality of converters, and voltage commands for the plurality of converters are set based on the set current trip order. Then, the set voltage commands are used to control the plurality of converters. This allows the load to be spread across the converters depending on the ratio of the thermal strength of the converters and the priority of the converters on previous trips. As a result, shortening of the life of a specific converter can be suppressed. Here, the "trip" is the period from the start of the system of the electric vehicle to the stop of the system.

In the first in-vehicle control device of the present invention, the priority of the plurality of converters is determined so that the ratio of the number of trips with the highest priority of each converter is the ratio of the thermal strength of each converter. A switching pattern may be set, and the current trip order may be set based on the switching pattern. As a result, the load can be distributed among a plurality of converters, and shortening of the life of a specific converter can be suppressed.

A second in-vehicle control device of the present invention includes:
A plurality of converters connected in parallel to two power lines for converting voltage between the two power lines, and a cooling system for cooling the plurality of converters using a cooling medium are both mounted on the vehicle, and the voltage command is An in-vehicle control device for controlling a plurality of the converters using
The heat accumulated in the plurality of converters based on the average value of the output currents of the plurality of converters, the average value of the input currents of the plurality of converters, and the maximum temperature difference of the cooling medium, which are calculated for each trip. Calculate cumulative heat stress indicative of stress,
A current trip order, which is a priority order of the plurality of converters in a current trip, is set based on the calculated accumulated thermal stresses of the plurality of converters, and the voltages of the plurality of converters are set based on the set current trip order. The gist of it is to set directives.

In the second in-vehicle control device of the present invention, the accumulated values in the plurality of converters are based on the average value of the output currents and the average value of the input currents of the plurality of converters and the maximum temperature difference of the cooling medium for each trip. calculating cumulative thermal stress indicating the thermal stress of the converters, setting priorities of the plurality of converters based on the calculated cumulative thermal stresses of the plurality of converters, and setting voltage commands for the plurality of converters based on the set priorities; . Then, the set voltage commands are used to control the plurality of converters. Thereby, the load can be distributed among the plurality of converters according to the accumulated thermal stress of the plurality of converters. As a result, shortening of the life of a specific converter can be suppressed. Here, "trip" is a period from when the system of the vehicle is started until when the system is stopped. The "maximum temperature difference of the cooling medium" is the difference between the maximum temperature of the cooling medium after the vehicle is started and the temperature of the cooling medium before the system is started.

In the second in-vehicle control device of the present invention, the converter having the greater calculated accumulated heat stress among the plurality of converters has lower priority than the converter having the smaller accumulated heat stress. The current trip order may be set. In this way, converters with greater cumulative thermal stress have lower priority, so that shortening of the life of converters with greater cumulative thermal stress can be suppressed.

In the second in-vehicle control device of the present invention, the converters having a smaller heat-related subtraction value obtained by subtracting the heat stress from the heat strength as the resistance to heat for the plurality of converters are the heat-related subtraction value The current trip order may be set such that it has a lower priority than the converter with a larger . Since the heat-related subtraction value is a value that reflects the heat margin of the converter, by lowering the priority of the converter with the smaller heat-related subtraction value, the load will be concentrated on the converter with less heat margin, and the life will be further extended. shortening can be suppressed. As a result, shortening of the life of a specific converter can be suppressed.

Further, in the first and second on-vehicle control devices of the present invention, the converter with the higher current trip order may set the voltage command higher than the converter with the lower current trip order.

1 is a configuration diagram showing a schematic configuration of an electric vehicle 20 equipped with an in-vehicle control device as a first embodiment of the present invention; FIG. 2 is a configuration diagram showing an outline of the configuration of a cooling system 60 of an electric vehicle 20; FIG. 3 is an explanatory diagram for explaining an example of a relationship between output voltages of converters P1 and P2 (voltage VL of power line 50 for auxiliary equipment) and current (load current) supplied to inverter 34 as a load; FIG. FIG. 10 is an explanatory diagram for explaining the transition of the current trip order Pn in each trip; FIG. 5 is a flowchart showing an example of a priority order setting routine executed by a vehicle ECU 70 in order to realize the transition of the current trip order Pn in each trip illustrated in FIG. 4; FIG. To explain the transition of the current trip order Pn at each trip in a modified electric vehicle in which three DC/DC converters are connected between the driving power line 36 and the auxiliary power line 50 is an explanatory diagram of . FIG. 11 is a flow chart showing an example of a priority order setting routine according to a modification; FIG. 4 is a flowchart showing an example of a priority order setting routine executed by a vehicle ECU 70 of an electric vehicle 120; 4 is a flowchart showing an example of a cumulative heat stress setting routine executed by a vehicle ECU 70 of electric vehicle 120. FIG. FIG. 11 is a flow chart showing an example of a priority order setting routine according to a modification; FIG. 1 shows an example of a priority order setting routine executed by a vehicle ECU 70 in a modified electric vehicle in which three DC/DC converters are connected between a drive power line 36 and an accessory power line 50; It is a flow chart. 7 is a flowchart showing an example of an accumulated heat stress setting routine executed by a vehicle ECU 70 of an electric vehicle according to a modification;

Next, a mode for carrying out the present invention will be described using examples.

FIG. 1 is a configuration diagram showing the outline of the configuration of an electric vehicle 20 equipped with an in-vehicle control device as a first embodiment of the present invention. FIG. 2 is a configuration diagram showing an outline of the configuration of the cooling system 60 of the electric vehicle 20. As shown in FIG. Note that FIG. 1 does not show the cooling system 60 . As shown in FIGS. 1 and 2, the electric vehicle 20 of the embodiment includes a running motor 32, an inverter 34, a drive power line 36, a system main relay 38, a battery 40 as a power storage device, A battery electronic control unit (hereinafter referred to as "battery ECU") 42, an auxiliary power line 50, a first DC/DC converter (hereinafter referred to as "first DDC") 52, and a second DC/DC converter (hereinafter referred to as 54 , an auxiliary device 56 , an auxiliary battery 58 , a cooling system 60 , and a vehicle electronic control unit (hereinafter referred to as “vehicle ECU”) 70 . The vehicle ECU 70 mainly corresponds to the in-vehicle control device of the embodiment.

The motor 32 is configured, for example, as a synchronous generator-motor, and the rotor of the motor 32 is connected to a drive shaft 26 that is coupled to the drive wheels 22 via a differential gear 24 . The inverter 34 is connected to the motor 32 and to a drive power line 36 . Motor 32 is rotationally driven by vehicle ECU 70 controlling switching of a plurality of switching elements (not shown) of inverter 34 . The system main relay 38 is provided on the drive power line 36 and connects and disconnects the inverter 34 side and the battery 40 side by turning it on and off.

The battery 40 is configured as, for example, a lithium ion secondary battery, and is connected to the drive power line 36 . The battery ECU 42 includes a microprocessor having a CPU, ROM, RAM, flash memory, input/output ports, and communication ports (not shown). Signals from various sensors are input to the battery ECU 42 through an input port. The signals input to the battery ECU 42 include, for example, the voltage Vb of the battery 40 from the voltage sensor 40a attached between the terminals of the battery 40, and the voltage Vb of the battery 40 from the current sensor 40b attached to the output terminal of the battery 40. Current Ib can be mentioned. The battery ECU 42 calculates the charge ratio SOC of the battery 40 based on the integrated value of the current Ib of the battery 40 (positive value when the battery 40 is discharged) from the current sensor 40b. The battery ECU 42 is connected to the vehicle ECU 70 via a communication port.

The first and second DDCs 52 and 54 are connected in parallel between the drive power line 36 and the auxiliary power line 50 connected to the auxiliary battery 58 having a lower rated voltage than the battery 40, The voltage of the drive power line 36 is converted (stepped down) and supplied to the accessory power line 50 . The first and second DDCs 52 and 54 have predetermined thermal strengths Hsh1 and Hsh2 as resistance to heat of the first and second DDCs 52 and 54 based on their respective hardware configurations. In the first example, it is assumed that the ratio of the thermal strength Hsh1 and the thermal strength Hsh2 is 2:1. The first and second DDCs 52 and 54 are controlled by the vehicle ECU 70 . An accessory 56 is connected to the accessory power line 50 . Note that the ratio of the thermal strength Hsh1 and the thermal strength Hsh2 may be different from 2:1.

The cooling system 60 has a radiator 62 and a water pump 64 . The radiator 62 mainly cools the cooling water (cooling medium) that circulates through the first DDC 52, the second DDC 54, and the inverter 34 in this order, using running wind. The water pump 64 pumps the cooling water that has circulated through the first DDC 52, the second DDC 54, and the inverter 34 to the radiator 62 side. Water pump 64 is controlled by vehicle ECU 70 .

The vehicle ECU 70 includes a microprocessor having a CPU, ROM, RAM, flash memory, input/output ports, and communication ports (not shown).

Signals from various sensors are input to the vehicle ECU 70 through input ports. Signals input to the vehicle ECU 70 include, for example, a rotational position θm of the rotor of the motor 32 from a rotational position sensor (for example, a resolver) that detects the rotational position of the rotor of the motor 32, and a start signal from the start switch 72. can be mentioned. Since the vehicle ECU 70 also functions as a drive control device for the vehicle, the vehicle ECU 70 includes a shift position sensor for detecting the operation position of the shift lever and an accelerator pedal position sensor for detecting the depression amount of the accelerator pedal. The degree of accelerator opening from a sensor, the brake pedal position from a brake pedal position sensor that detects the amount of depression of the brake pedal, and the vehicle speed from a vehicle speed sensor are input. The vehicle ECU 70 also includes input currents Iin1 and Iin2 from current sensors (not shown) that detect currents input from the driving power line 36 to the first and second DDCs 52 and 54, and compensation currents from the first and second DDCs 52 and 54. output currents Iout1 and Iout2 from current sensors (not shown) that detect the current output to the machine power line 50; cooling water temperature Tw is input.

Various control signals are output from the vehicle ECU 70 through an output port. Signals output from the vehicle ECU 70 include, for example, control signals to a plurality of switching elements of the inverter 34, control signals to the system main relay 38, and control signals to the first and second DDCs 52 and 54. . The vehicle ECU 70 is connected to the battery ECU 42 via a communication port.

The vehicle ECU 70 calculates average input currents AIin1 and AIin2 obtained by dividing the input currents Iin1 and Iin2 detected by a current sensor (not shown) by the elapsed time since the start switch 72 was turned on and the system was activated. Average output currents AIout1 and AIout2 are calculated by dividing the output currents Iout1 and Iout2 detected by a current sensor (not shown) by the elapsed time since the start switch 72 was turned on and the system was started. Further, the maximum temperature difference ΔTw is obtained by subtracting the cooling water temperature (just before) Tw immediately before the start switch 72 is turned on from the maximum value of the cooling water temperature Tw detected by the temperature sensor 60a after the start switch 72 is turned on and the system is started. is also calculated. The average input currents AIin1 and AIin2, the average output currents AIout1 and AIout2, and the maximum temperature difference ΔTw are reset to 0 after the start switch 72 is turned off and a system-off request is made, and cumulative thermal stresses Chs1 and Chs2, which will be described later, are calculated. be done. Therefore, average input currents AIin1, AIin2, average output currents AIout1, AIout2, and maximum temperature difference ΔTw are values for each trip. Here, the term "trip" refers to the period from when the start switch 72 is turned on and the system is activated until when the start switch 72 is turned off and the system stops.

In the electric vehicle 20 of the embodiment thus configured, the system main relay 38 is turned on to supply electric power from the battery 40 to the motor 32 via the drive power line 36 and the inverter 34, thereby supplying power from the motor 32. run by

For the first and second DDCs 52 and 54, the vehicle ECU 70 outputs the voltage command VLO1* for the first DDC 52 and the voltage for the second DDC 54 based on the current trip order Pn as the priority of the current trip of the first and second DDCs 52 and 54. A command VLO2* is set, and the first and second DDCs 52 and 54 are controlled by the set voltage commands VLO1* and VLO2*. The setting of the current trip order Pn will be described later. Voltage commands VLO1* and VLO2* are set by setting voltage VP1 as the voltage command for converter P1, which has the highest priority among the first and second DDCs 52 and 54 in the current trip order Pn. , a voltage VP2 lower than the voltage VP1 is set as the voltage command for the converter P2, which has a lower priority than the converter P1 (second priority). In the embodiment, the voltage VP1 is set to a value that varies according to the temperature, output, etc. of the motor 32, and the voltage VP2 is changed from the voltage VP1 by a voltage ΔVref (for example, 0.8 V, 1.0 V, 1.2 V, etc.). It is set using the following formula (1) so as to be low.

VP2=VP1-ΔVref (1)

Then, vehicle ECU 70 controls converter P1, which has the highest priority, so that the output voltage of converter P1 becomes the voltage command (voltage VP1). For converter P2, which has a lower priority than converter P1, when the output voltage of converter P2 is equal to or lower than the voltage command (voltage VP2), converter P2 is controlled so that the output voltage of converter P2 becomes equal to the voltage command (voltage VP2). , when the output voltage of the converter P2 exceeds the voltage command (voltage VP2), the driving of the converter P2 is stopped. By such control, the converter P1 is driven with priority over the converter P2.

For example, when the first DDC 52 has a higher priority than the second DDC 54 in the current trip order Pn among the first and second DDCs 52 and 54, the voltage command VLO1* is set to the voltage VP1, and the voltage command VLO2* is set to the voltage VP2. set. Then, the first DDC 52 is controlled so that the output voltage of the first DDC 52 becomes the voltage command VLO1* (=VP1). Regarding the second DDC 54, when the output voltage of the second DDC 54 is equal to or lower than the voltage command VLO2* (=VP2), the converter P2 is controlled so that the output voltage of the second DDC 54 becomes the voltage command VLO2* (=VP2). exceeds the voltage command VLO2* (=VP2), the driving of the second DDC 54 is stopped.

FIG. 3 is an explanatory diagram for explaining an example of the relationship between the output voltages of converters P1 and P2 (voltage VL of auxiliary equipment power line 50) and the current (load current) supplied to inverter 34 as a load. be. When the load current is low, the output of the load can be covered by driving converter P1, so the output voltage of converter P1 (voltage VL of auxiliary equipment power line 50) is maintained near voltage VP1. . When the load current increases, even if converter P1 is driven, the output of the load cannot be covered, and the output voltage of converter P1 (voltage VL of auxiliary machine power line 50) becomes lower than voltage VP1. Furthermore, when the load current increases, the output voltage of converter P1 (voltage VL of power line 50 for auxiliary equipment) further drops and becomes equal to or lower than the voltage command for converter P2 (voltage VP2), converter P2 starts driving. Thus, as the output of the load increases, converter P1 and converter P2 start driving in this order. That is, the converter P1 is preferentially driven. Through such control, the first and second DDCs 52 and 54 can be driven based on the current trip order Pn.

Next, the operation of the electric vehicle 20 of the first embodiment configured as described above, in particular, the operation when setting the current trip order Pn will be described.

In the first embodiment, the ratio of the thermal strengths Hsh1 and Hsh2 of the first and second DDCs 52 and 54, the previous trip order Ppre as the priority order in the previous trip, and the pre-previous trip order as the priority order in the trip before the previous trip. The current trip order Pn is set based on Pppre. FIG. 4 is an explanatory diagram for explaining the transition of the current trip order Pn in each trip. The current trip order Pn is, as shown in the figure, "1st: 1st DDC 52, 2nd: 2nd DDC 54", "1st: 1st DDC 52, 2nd: 2nd DDC 54", and "1st: 2nd DDC 54". , 2nd: first DDC 52” are set so as to repeatedly transit in this order. By setting the current trip order Pn in this way, the number of trips Nt1 in which the first DDC 52 is ranked first among the current trip and the past two trips (the previous trip and the trip before the previous one) The ratio of the number of trips Nt2, which is the highest, can be 2:1, that is, the ratio (2:1) of the thermal strength Hsh1 of the first DDC 52 and the thermal strength Hsh2 of the second DDC 54 can be the same. .

FIG. 5 is a flowchart showing an example of a priority order setting routine executed by the vehicle ECU 70 to realize the transition of the current trip order Pn for each trip illustrated in FIG. This routine is executed each time the start switch 72 is switched from off to on to start the system, that is, it is executed at each trip.

When this routine is executed, the CPU of the vehicle ECU 70 checks the previous trip order Ppre as the priority order of the previous trip (step S100), and determines the pre-previous trip order Pppre as the priority order of the trip before the previous trip. Check (step S110).

When the highest priority in the previous trip order Ppre and the trip order Pppre before the previous trip is the first DDC 52 (priority is given to the first DDC) (steps S100, S110), the current trip order Pn has the highest priority (first priority). The first DDC 54 is set to the converter P1, and the first DDC 52 is set to the converter P2, which has a lower priority than the converter P1 (second priority) (step S120), and this routine ends.

After setting the current trip order Pn in this way, the CPU of the vehicle ECU 70 sets the voltage command VLO2* for the second DDC 54 to the voltage VP1 and the voltage command VLO1* for the first DDC 52 to the voltage VP2 based on the set current trip order Pn. do. Then, the converter P1 (here, the second DDC 54) having the highest priority is controlled so that the output voltage of the converter P1 becomes the voltage command (voltage command VLO2* (=VP1)). For converter P2 (here, first DDC 52) having a lower priority than converter P1, when the output voltage of converter P2 is equal to or lower than the voltage command (voltage command VLO1*(=VP2)), the output voltage of converter P2 is equal to or lower than the voltage command. (voltage command VLO1* (=VP2)), and stops driving converter P2 when the output voltage of converter P2 exceeds the voltage command (voltage command VLO1* (=VP2)). do.

When the first priority in the previous trip order Ppre is the second DDC 54 (second DDC is given priority) (step S100), the first DDC 52 (first DDC is given priority) in the previous trip order Ppre, In addition, when the second DDC 54 (second DDC has priority) in the trip order Pppre before the previous one (steps S100, S110), the first DDC 52 is set to the converter P1 and the second DDC 54 is set to the converter P2. (Step S130), this routine ends.

After setting the current trip order Pn in this way, the CPU of the vehicle ECU 70 sets the voltage command VLO1* for the first DDC 52 to the voltage VP1 and the voltage command VLO2* for the second DDC 54 to the voltage VP2 based on the set current trip order Pn. do. Then, the converter P1 (here, the first DDC 52) having the highest priority is controlled so that the output voltage of the converter P1 becomes the voltage command (voltage command VLO1* (=VP1)). For converter P2 (here, second DDC 54) having a lower priority than converter P1, when the output voltage of converter P2 is equal to or lower than the voltage command (voltage command VLO2*(=VP2)), the output voltage of converter P2 is equal to or lower than the voltage command. (voltage command VLO2* (=VP2)), and stops driving converter P2 when the output voltage of converter P2 exceeds the voltage command (voltage command VLO2* (=VP2)) do.

In this way, by making the ratio of the number of trips Nt1 and the number of trips Nt2 the same as the ratio of the thermal strength Hsh1 of the first DDC 52 and the thermal strength Hsh2 of the second DDC 54, the service life of the second DDC 54, which is weaker against heat, is extended. can be suppressed from further shortening. Also, by switching the current trip order Pn, the load can be distributed between the first DDC 52 and the second DDC 54 . As a result, it is possible to prevent the load from concentrating on a specific converter and shortening the life of the converter.

According to the electric vehicle 20 equipped with the in-vehicle control device of the first embodiment described above, the ratio of the thermal strengths Hsh1 and Hsh2 of the first and second DDCs 52 and 54, the previous trip order Ppre, the trip order Pppre before the previous trip, and set the voltage commands VLO1* and VLO2* for the first and second DDCs 52 and 54 based on the set current trip order Pn. It is possible to suppress the shortening of the service life.

In the electric vehicle 20 equipped with the in-vehicle control device of the first embodiment, two DC/DC converters (first and second DDCs 52, 54) are provided between the drive power line 36 and the accessory power line 50. It is connected. However, three or more DC/DC converters may be connected between drive power line 36 and accessory power line 50 . In this case, the current ratio is such that the ratio of the thermal strengths of the multiple DC/DC converters and the ratio of the number of trips in which the multiple converters have the highest priority in the prior trip priority are the same. A trip order Pn may be set.

FIG. 6 shows three DC/DC converters (first, second DDCs 52, 54, and third DC/DC converters (hereinafter referred to as "third DDC") between the driving power line 36 and the auxiliary equipment power line 50. ) 55) is an explanatory diagram for explaining the transition in each trip of the current trip order Pn in the electric vehicle of the modification to which 55) is connected. In the electric vehicle of the modified example, the ratio of the thermal strengths Hsh1v to Hsh3v of the first to third DDCs 52, 54, 55 is 2:1:1. In the electric vehicle of the modified example, the current trip order Pn is, as shown in the figure, "1st: 1st DDC 52, 2nd: 2nd DDC 54, 3rd: 3rd DDC 55", "1st: 1st DDC 52, 3rd 2nd place: 2nd DDC54, 3rd place: 3DDC55", 1st place: 2nd DDC54, 2nd place: 3DDC55, 3rd place: 1st DDC52", "1st place: 3DDC55, 2nd place: 3rd place 1DDC52, 3rd: 2nd DDC54", are set so as to repeatedly transit in this order. By setting the current trip order Pn in this manner, the number of trips Nt1v in which the first DDC 52 ranks first and the number of trips Nt2v in which the second DDC 54 ranks first among the current trip and the past three trips and the number of trips Nt3v in which the third DDC 55 is ranked first is 2:1:1, and the ratio of the thermal strength Hsh1v of the first DDC 52, the thermal strength Hsh2v of the second DDC 54, and the thermal strength Hsh3v of the third DDC 55 is 2 : can be the same as 1:1.

FIG. 7 is a flow chart showing an example of a priority order setting routine according to a modification. In the electric vehicle of this modified example, instead of the priority setting routine of FIG. 5 of the first embodiment, the priority setting routine of the modified example of FIG. 7 is executed.

When the priority order setting routine of the modified example is executed, the CPU of the vehicle ECU 70 examines the previous trip order Ppre as the priority order of the previous trip (step S200) and the previous trip order Ppre as the priority order of the trip before the previous trip. Each trip order Pppre is checked (step S210).

When the first priority in the previous trip order Ppre is the 3DDC 55 (3DDC is given priority) (step S200), or when the first priority in the previous trip order Ppre is the first DDC 52 (first DDC is given priority), In addition, when the highest priority in the trip order Pppre before the previous one is the 3DDC 55 (3DDC is given priority) (steps S200, S210), the current trip order Pn has the highest priority. ) sets the first DDC 52 to the converter P1, sets the second DDC 54 to the converter P2 having a lower priority than the converter P1 (second priority), and sets the second DDC 54 to the converter P2 having the lowest priority in the current trip order Pn. The third DDC 55 is set in the converter P3 (third rank) (step S220), and the priority order setting routine ends.

When the first DDC 52 (first DDC has priority) in the previous trip order Ppre and the trip order Pppre before the previous trip (steps S200, S210), the second DDC 54 is set in the converter P1 and the third DDC 55 is set in the converter P2. Then, the converter P3 is set to the first DDC 52 (step S230), and the priority order setting routine ends.

When the first priority in the previous trip order Ppre is the second DDC 54 (second DDC is given priority) (step S200), the third DDC 55 is set to the converter P1, the first DDC 52 is set to the converter P2, and the second DDC 54 is set to the converter P3. is set (step S240), and the priority order setting routine ends. Through such processing, the transition illustrated in FIG. 6 can be realized.

In the electric vehicle 20 equipped with the in-vehicle control device of the first embodiment, the ratio of the numbers of trips Nt1 and Nt2 in which the first and second DDCs 52 and 54 have the highest priority is The order of transition (switching pattern) is set so as to be the same as the ratio of the thermal strengths Hsh1 and Hsh2. However, since the current trip order Pn can be set based on the ratio of the thermal strengths Hsh1 and Hsh2, the previous trip order Ppre, and the trip order Pppre before the previous one, the ratio of the number of trips Nt1 and Nt2 is the first, The ratio of the thermal strengths Hsh1 and Hsh2 of the second DDCs 52 and 54 does not have to be the same as long as the ratio of the thermal strengths Hsh1 and Hsh2 is close. For example, when the ratio of the thermal strengths Hsh1 and Hsh2 of the first and second DDCs 52 and 54 is 2:1, the ratio of the number of trips Nt1 and Nt2 may be 3:1 or 5:3.

In the electric vehicle 20 equipped with the in-vehicle control device of the first embodiment, the current trip order Pn is set based on the ratio of the thermal strengths Hsh1 and Hsh2, the previous trip order Ppre, and the trip order before the previous trip Pppre. . However, the current trip priority Pn can be set based on the ratio of the thermal strengths Hsh1 and Hsh2 and the priority in the previous trip (current trip priority Pn in the previous trip). The current trip order Pn may be set based on the ratio of Hsh1 and Hsh2 and the previous trip order Ppre. A trip order Pn may be set.

Next, an electric vehicle 120 equipped with the vehicle-mounted control device of the second embodiment will be described. The electric vehicle 120 has the same hardware configuration as the electric vehicle 20, and instead of setting the current trip order Pn shown in FIGS. Identical processing is performed, except for a point. Therefore, description of the same hardware configuration and the same processing as those of the electric vehicle 20 will be omitted.

FIG. 8 is a flowchart showing an example of a priority order setting routine executed by the vehicle ECU 70 of the electric vehicle 120. As shown in FIG. The priority order setting routine is executed each time the start switch 72 is switched from off to on to start the system, that is, every trip.

When the priority order setting routine is executed, the CPU of the vehicle ECU 70 calculates the thermal strengths Hsh1 and Hsh2 of the first and second DDCs 52 and 54 described in the first embodiment and the cumulative thermal stress Chs1 of the first and second DDCs 52 and 54. , Chs2 are input (step S300). Here, interrupting the description of the priority order setting routine, the process of setting the cumulative thermal stresses Chs1 and Chs2 of the first and second DDCs 52 and 54 will be described.

FIG. 9 is a flow chart showing an example of an accumulated heat stress setting routine executed by vehicle ECU 70 of electric vehicle 120 . This routine is executed from when the start switch 72 is turned off and a request to stop the system is made until the system stops.

When the cumulative heat stress setting routine is executed, the CPU of the vehicle ECU 70 executes a process of inputting the calculated average input currents AIin1, AIin2, average output currents AIout1, AIout2, and maximum temperature difference ΔTw (step S400). Using the average input currents AIin1 and AIin2, the average output currents AIout1 and AIout2, and the maximum temperature difference ΔTw, the thermal stress Hs1 at the current trip acting on the first and second DDCs 52 and 54 is calculated by the following equations (2) and (3): , Hs2 are calculated (step S410). In the equations (2) and (3), "α1" and "α2" are determined in advance by experiments and analyses, as conversion coefficients for converting the average output currents AIout1 and AIout2 into thermal stress. "β1" and "β2" are determined in advance through experiments and analysis as conversion coefficients for converting the average input currents AIin1 and AIin2 into thermal stress. “γ1” and “γ2” are determined in advance through experiments and analysis as conversion coefficients for converting the maximum temperature difference ΔTw into thermal stress. α1 and α2 may be the same value or may be different values. β1 and β2 may be the same value or different values. γ1 and γ2 may be the same value or different values.

Hs1=α1・AIout1+β1・AIin1+γ1・ΔTw (2)
Hs2=α2・AIout2+β2・AIin2＋γ2・ΔTw (3)

After calculating the heat stresses Hs1 and Hs2 of the first and second DDCs 52 and 54 in this manner, the heat stress Hs1 calculated in step S410 is added to the accumulated heat stress (previous) Chs1 calculated when the accumulated heat stress setting routine was executed in the previous trip. is added to calculate the cumulative heat stress Chs1 as the heat stress accumulated in the first DDC 52, and the heat calculated in step S410 is added to the cumulative heat stress (previous) Chs2 calculated when the cumulative heat stress setting routine was executed in the previous trip. A cumulative heat stress Chs2 is calculated as the heat stress accumulated in the second DDC 54 by adding the stress Hs2 (step S420), and the cumulative heat stress setting routine ends. Calculation of the cumulative thermal stresses Chs1 and Chs2 of the first and second DDCs 52 and 54 has been described above.

Returning to the description of the priority setting routine. When the heat strengths Hsh1 and Hsh2 and the cumulative heat stresses Chs1 and Chs2 are input in step S300, the heat-related subtraction value Sb1 (=Hsh1-Chs1) obtained by subtracting the cumulative heat stress Chs1 from the heat strength Hsh1 is the heat strength Hsh2. is greater than a heat-related subtraction value Sb2 (=Hsh2-Chs2) obtained by subtracting the cumulative heat stress Chs2 from (step S310). The heat-related subtraction value Sb1 reflects the degree of margin for future heat stress of the first DDC 52 . Similarly, the heat-related subtraction value Sb2 reflects the extent to which the second DDC 54 can withstand future heat stress. Therefore, the process of step S310 is a process of determining whether or not the first DDC 52 has more heat margin than the second DDC .

When it is determined in step S310 that the heat-related subtraction value Sb1 is greater than the heat-related subtraction value Sb2, it is determined that the first DDC 52 has more heat margin than the second DDC 54, and the current trip order Pn has the highest priority (priority The first DDC 52 is set in the converter P1 with the first priority, and the second DDC 54 is set in the converter P2 with a lower priority (second priority) than the converter P1 (step S320) to set the priority. Exit the routine.

After setting the current trip order Pn in this way, the CPU of the vehicle ECU 70 sets the voltage command VLO1* for the first DDC 52 to the voltage VP1 and the voltage command VLO2* for the second DDC 54 to the voltage VP2 based on the set current trip order Pn. do. Then, the converter P1 (here, the first DDC 52) having the highest priority is controlled so that the output voltage of the converter P1 becomes the voltage command (voltage command VLO1* (=VP1)). For converter P2 (here, second DDC 54) having a lower priority than converter P1, when the output voltage of converter P2 is equal to or lower than the voltage command (voltage command VLO2*(=VP2)), the output voltage of converter P2 is equal to or lower than the voltage command. (voltage command VLO2* (=VP2)), and stops driving converter P2 when the output voltage of converter P2 exceeds the voltage command (voltage command VLO2* (=VP2)) do.

As described above, the heat-related subtraction values Sb1 and Sb2 are values that reflect the heat margins of the first and second DDCs 52 and 54. Therefore, the priority of the second DDC 54 having a smaller heat-related subtraction value is compared to the first DDC 52. By lowering it, it is possible to prevent the load from concentrating on the second DDC 54, which has little margin for heat, and further shorten the life of the DDC. As a result, shortening of the life of a specific converter can be suppressed.

When it is determined in step S310 that the heat-related subtraction value Sb1 is less than or equal to the heat-related subtraction value Sb2, the converter P1 is set to the second DDC 54 and the converter P1 is set to the first DDC 52 (step S330), and this routine ends.

After setting the current trip order Pn in this way, the CPU of the vehicle ECU 70 sets the voltage command VLO2* for the second DDC 54 to the voltage VP1 and the voltage command VLO1* for the first DDC 52 to the voltage VP2 based on the set current trip order Pn. do. Then, the converter P1 (here, the second DDC 54) having the highest priority is controlled so that the output voltage of the converter P1 becomes the voltage command (voltage command VLO2* (=VP1)). For converter P2 (here, first DDC 52) having a lower priority than converter P1, when the output voltage of converter P2 is equal to or lower than the voltage command (voltage command VLO1*(=VP2)), the output voltage of converter P2 is equal to or lower than the voltage command. (voltage command VLO1* (=VP2)), and stops driving converter P2 when the output voltage of converter P2 exceeds the voltage command (voltage command VLO1* (=VP2)). do.

By setting the priority of the first DDC 52 lower than that of the second DDC 54, it is possible to prevent the load from concentrating on the first DDC 52, which has the same or less margin for heat than the second DDC 54, and further shorten the life. As a result, shortening of the life of a specific converter can be suppressed.

According to the electric vehicle 20 equipped with the in-vehicle control device of the second embodiment described above, the average output current AIout1, Based on AIout2, average input currents AIin1 and AIin2 as average values of the input currents Iin1 and Iin2 of the first and second DDCs 52 and 54, and maximum temperature difference ΔTw, cumulative thermal stress Chs1 of the first and second DDCs 52 and 54 , Chs2 are calculated, the current trip order Pn is set based on the difference between the thermal strength Hsh1, Hsh2 and the accumulated thermal stress Chs1, Chs2, and the voltages of the first and second DDCs 52, 54 are set based on the set current trip order Pn. By setting the commands VLO1* and VLO2*, shortening of the life of a specific converter can be suppressed.

In the electric vehicle 120 equipped with the in-vehicle control device of the second embodiment, in step S310, the heat-related subtraction value Sb1 obtained by subtracting the accumulated heat stress Chs1 from the heat strength Hsh1 is obtained by subtracting the accumulated heat stress Chs2 from the heat strength Hsh2. It is determined whether or not it is greater than the heat-related subtraction value Sb2 obtained by However, as illustrated in the priority order setting routine of the modified example of FIG. 10, the processes of steps S300a and S310a may be executed instead of the processes of steps S300 and S310.

In step S300a, cumulative heat stresses Chs1 and Chs2 are input, and in step S310a, it is determined whether cumulative thermal stress Chs1 is smaller than cumulative thermal stress Chs2. A DC/DC converter with a small cumulative thermal stress is considered to have a margin against thermal stress compared to a DC/DC converter with a large cumulative thermal stress. Therefore, when the accumulated heat stress Chs1 is smaller than the accumulated heat stress Chs2 in step S310a, step S320 is executed to set the first DDC 52 to the converter P1, set the second DDC 54 to the converter P2, and set the second DDC 54 to the first DDC 52. By preferentially operating the second DDC 54, it is possible to suppress the application of further thermal stress to the second DDC 54, which has no margin for thermal stress. This can prevent the life of the second DDC 54 from being shortened.

When the accumulated heat stress Chs1 is equal to or greater than the accumulated heat stress Chs2 in step S310a, step S330 is executed to set the second DDC 54 to the converter P1, set the first DDC 52 to the converter P2, and set the first DDC 52 to the second DDC 54. By preferentially operating, further thermal stress can be suppressed from being applied to the first DDC 52 which has no margin for thermal stress. As a result, shortening of the life of the first DDC 52 can be suppressed.

In the electric vehicle 120 equipped with the in-vehicle control device of the second embodiment, two DC/DC converters (first and second DDCs 52, 54) are provided between the driving power line 36 and the auxiliary power line 50. It is connected. However, three or more DC/DC converters may be connected between drive power line 36 and accessory power line 50 . In this case, the current trip order Pn may be set based on the heat-related subtraction value of each DC/DC converter. Here, for convenience of explanation, three DC/DC converters (first to third DDCs 52, 54, 55) are connected between the drive power line 36 and the accessory power line 50. and The 3DDC 55 has a predetermined thermal strength Hsh3 as strength against heat of the 3DDC 44 based on the hardware configuration and the like.

When three DC/DC converters (first to third DDCs 52, 54, 55) are connected between the driving power line 36 and the auxiliary equipment power line 50, the vehicle ECU 70 controls the driving power line The average input current AIin3 obtained by dividing the input current Iin3 detected by a current sensor (not shown) that detects the current input from 36 to the third DDC 55 by the elapsed time after the start switch 72 is turned on and the system is started is The output current Iout3 detected by a current sensor (not shown) that detects the current output from the third DDC 55 to the accessory power line 50 is divided by the elapsed time after the start switch 72 is turned on and the system is started. Then, an average output current AIout3 is calculated. The average input current AIin3 and the average output current AIout3 are reset to 0 after the start switch 72 is turned off and a system-off request is made, and after an accumulated thermal stress Chs3, which will be described later, is calculated. Therefore, average input current AIin3 and average output current AIout3 are calculated for each trip.

FIG. 11 shows a modified electric vehicle in which three DC/DC converters (first to third DDCs 52, 54, 55) are connected between a driving power line 36 and an auxiliary power line 50. 3 is a flowchart showing an example of a priority order setting routine executed by a vehicle ECU 70; The priority order setting routine is executed each time the start switch 72 is switched from off to on to start the system, that is, every trip.

When the priority order setting routine is executed, the CPU of the vehicle ECU 70 calculates the thermal strengths Hsh1 and Hsh2 of the first and second DDCs 52 and 54 and the cumulative heat stresses Hsh1 and Hsh2 of the first and second DDCs 52 and 54 in the same manner as in step S300 of the priority order setting routine illustrated in FIG. A process of inputting Chs1 and Chs2, as well as the heat strength Hsh3 and cumulative heat stress Chs3 of the third DDC 55 is executed (step S500). Now, interrupting the description of the priority order setting routine, the processing for calculating the cumulative heat stresses Chs1 to Chs3 of the first to third DDCs 52, 54, 55 will be described.

FIG. 12 is a flow chart showing an example of an accumulated heat stress setting routine executed by the vehicle ECU 70 of the electric vehicle of the modification. This routine is executed from when the start switch 72 is turned off and a request to stop the system is made until the system stops.

When the cumulative heat stress setting routine is executed, the CPU of the vehicle ECU 70 sets average input currents AIin1, AIin2, average output currents AIout1, AIout2, The maximum temperature difference ΔTw is input, and the average input current AIin3 and average output current AIout3 are also input (step S600).

Then, using the average input currents AIin1 and AIin2, the average output currents AIout1 and AIout2, and the maximum temperature difference ΔTw that have been input, the current trip acting on the first and second DDCs 52 and 54 is obtained by the above equations (2) and (3). , and the input average input current AIin3, average output current AIout3, and maximum temperature difference ΔTw are used to calculate the thermal stress Hs3 at the current trip acting on the third DDC 55 by the following equation (4): is calculated (step S610). In equation (4), "α3" is determined in advance through experiments, analysis, or the like as a conversion coefficient for converting the average output current AIout3 into thermal stress. "β3" is determined in advance by experimentation, analysis, or the like as a conversion coefficient for converting the average input current AIin3 into thermal stress. "γ3" is determined in advance by experimentation, analysis, or the like as a conversion coefficient for converting the maximum temperature difference ΔTw into thermal stress. α3 may be the same value as α1 and α2 in formulas (2) and (3), or may be a different value. β3 may be the same value as β1 and β2 in formulas (2) and (3), or may be a different value. γ3 may be the same value as γ1 and γ2 in formulas (2) and (3), or may be a different value.

Hs3=α3・AIout3+β3・AIin3＋γ3・ΔTw (4)

After calculating the thermal stresses Hs1 to Hs3 of the first to third DDCs 52, 54, 55 in this way, the cumulative thermal stresses Chs1, Chs2 are calculated in the same manner as in step S420 of the cumulative thermal stress setting routine illustrated in FIG. The heat stress Hs3 calculated in step S610 is added to the cumulative heat stress (previous) Chs3 calculated when the cumulative heat stress setting routine was executed in the previous trip to calculate the cumulative heat stress Chs3 as the heat stress accumulated in the third DDC 55. Then (step S620), the cumulative heat stress setting routine ends. Calculation of the cumulative thermal stresses Chs1 to Chs3 of the first to third DDCs 52, 54, 55 has been described above.

Returning to the description of the priority setting routine. When the heat strengths Hsh1 to Hsh3 and the cumulative heat stresses Chs1 to Ch3 are input in step S500, heat-related subtraction values Sb1 and Sb2 are calculated in the same manner as in step S310 of the priority order setting routine illustrated in FIG. , the cumulative heat stress Chs3 is subtracted from the heat strength Hsh3 to calculate a heat-related subtraction value Sb3 (=Hsh3-Chs3) (step S510). The heat-related subtraction value Sb3 reflects the degree of margin for future heat stress of the third DDC 55 .

Then, the current trip order Pn is set so that the DC/DC converters with the largest heat-related subtraction values Sb1 to Sb3 have higher priority (step S520), and the priority order setting routine ends. This process lowers the priority of DC/DC converters with small heat-related subtraction values compared to DC/DC converters with large heat-related subtraction values, so that the life of DC/DC converters with small heat-related subtraction values and less heat margin is shortened. can be prevented from becoming

In the electric vehicles 20 and 120 equipped with the in-vehicle controllers of the first and second embodiments, two DC/DC converters (first and second 2DDC 52, 54) are connected. However, between drive power line 36 and auxiliary equipment power line 50, a plurality of converters may be connected to convert voltages for stepping up or stepping down.

In the first and second embodiments, the case where the in-vehicle control device of the present invention is installed in an electric vehicle that runs using the power of the motor 32 is exemplified. However, the present invention is not limited to being installed in an electric vehicle, but is installed in a vehicle together with a plurality of converters connected in parallel to two power lines to convert voltage between the two power lines, Any device that controls a plurality of converters using a voltage command may be applied.

The correspondence relationship between the main elements of the embodiments and the main elements of the invention described in the column of Means for Solving the Problems will be described. In the first and second embodiments, the vehicle ECU 70 corresponds to the "vehicle control device".

Note that the correspondence relationship between the main elements of the examples and the main elements of the invention described in the column of Means for Solving the Problems is the Since it is an example for specifically explaining the mode for solving the problem, it does not limit the elements of the invention described in the column of the means for solving the problem. That is, the interpretation of the invention described in the column of Means to Solve the Problem should be made based on the description in that column, and the Examples are based on the description of the invention described in the column of Means to Solve the Problem. This is only a specific example.

Although the embodiments for carrying out the present invention have been described above, the present invention is not limited to such embodiments at all, and can be modified in various forms without departing from the scope of the present invention. Of course, it can be implemented.

INDUSTRIAL APPLICABILITY The present invention can be used in the manufacturing industry of in-vehicle control devices.

20, 120 electric vehicle, 22 drive wheel, 24 differential gear, 26 drive shaft, 32 motor, 34 inverter, 36 drive power line, 38 system main relay, 40 battery, 40a voltage sensor, 40b current sensor, 42 battery ECU, 50 charging power line, 52 first DC/DC converter (first DDC), 54 second DC/DC converter (second DDC), 55 third DC/DC converter (third DDC), 56 auxiliary equipment, 58 auxiliary battery, 60 cooling system, 60a temperature sensor, 62 radiator, 64 water pump, 70 vehicle ECU, 72 start switch.

Claims (2)

An in-vehicle control device that is mounted on a vehicle together with a plurality of converters that are connected in parallel to two power lines and convert voltage between the two power lines, and that controls the plurality of converters using a voltage command,
Based on the ratio of thermal strength as strength to heat of the converters and the priority of the converters on the previous trip, the current priority of the converters on the current trip. An in-vehicle control device that sets a trip order and sets the voltage commands for the plurality of converters based on the set current trip order. A plurality of converters connected in parallel to two power lines for converting voltage between the two power lines, and a cooling system for cooling the plurality of converters using a cooling medium are both mounted on the vehicle, and the voltage command is An in-vehicle control device for controlling a plurality of the converters using
The heat accumulated in the plurality of converters based on the average value of the output currents of the plurality of converters, the average value of the input currents of the plurality of converters, and the maximum temperature difference of the cooling medium, which are calculated for each trip. Calculate cumulative heat stress indicative of stress,
A current trip order, which is a priority order of the plurality of converters in a current trip, is set based on the calculated accumulated thermal stresses of the plurality of converters, and the voltages of the plurality of converters are set based on the set current trip order. In-vehicle controller for setting commands.

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