JP2019097361A - Control device of electric vehicle - Google Patents

Abstract

To provide a control device of an electric vehicle which can prevent the overheat of a brake while suppressing the deterioration of a battery.SOLUTION: When a charge amount E is not smaller than a first charge amount E1, a vehicle speed V is not lower than a prescribed vehicle speed V1, a gradient θ is not larger than a prescribed gradient θ1, and a brake temperature T is not lower than an upper limit value Tmax in a proper temperature range (YES in S1 to S4), a brake control part 11 of a control device 10 of a vehicle 1 performs the forcible discharge control of a battery 4 by an electric auxiliary machine 8, and performs regeneration control by a traveling motor 2 (S5).SELECTED DRAWING: Figure 3

Description

  The present invention relates to a control device for an electrically powered vehicle, and more particularly to a control device for forced discharge of a battery and regenerative braking of a motor during traveling on a continuous downhill.

  For example, when the electric vehicle travels on a continuous descending slope, the battery charge (SOC: State of Charge) is fully charged by the regeneration control, and there is a possibility that the regenerative braking force by the regeneration control can not be used. In order to avoid such a situation, it has been studied to perform regenerative control by performing a forced discharge with a motor auxiliary and reducing the charge amount of the battery (see Patent Document 1).

JP, 2012-111270, A

  However, if the vehicle travels on a continuous descending slope or the like while performing such control, forced discharge and regenerative charging of the battery by the auxiliary equipment are frequently repeated, leading to deterioration of the battery and deterioration of electricity cost due to unnecessary forced discharge. There is a risk.

  On the other hand, when considering traveling by the braking force by the brake without using the regenerative braking, the electric truck which can not use the engine brake does not use the regenerative braking because the braking capacity with respect to the vehicle weight is smaller than that of the passenger car. There is a possibility that the braking force may be reduced due to overheat of the brake.

  An object of the present invention is to provide a control device of an electric-powered vehicle capable of reliably preventing overheat of the brake while suppressing deterioration of the battery and deterioration of the electricity cost.

  The present invention has been made to solve at least a part of the above-mentioned problems, and can be realized as the following aspects or application examples.

  (1) A control device of an electric vehicle according to the application example is a control device of a vehicle equipped with a drive battery for supplying electric power to a drive motor, and the drive is performed by regeneratively driving the drive motor. A regenerative braking control unit that performs regenerative control to cause the vehicle to generate regenerative braking while charging the battery with regenerative power; and a brake mechanism that has a predetermined appropriate temperature range and causes the vehicle to generate a braking force; A forced discharge control unit that implements forced discharge control that forcibly reduces the charge amount of the drive battery by driving an accessory mounted on the vehicle, and a brake temperature acquisition unit that acquires the brake temperature of the brake mechanism , A charge amount acquisition unit for acquiring the charge amount of the drive battery, and a braking control unit for controlling the regenerative braking control unit, the braking mechanism, and the forced discharge control unit. The braking control unit performs braking control by the brake mechanism as the braking control when the braking temperature is within the appropriate temperature range, and the braking temperature is higher than the upper limit value of the appropriate temperature range. In this case, the forced discharge control by the forced discharge control unit and the regenerative control by the regenerative braking control unit are performed.

  That is, by utilizing the braking by the brake mechanism when the brake temperature is within the proper temperature range, it is possible to avoid a situation where the battery is forcibly discharged by the accessory and the regenerative charging is frequently repeated by the regenerative control. . On the other hand, when the brake temperature becomes higher than the upper limit value of the appropriate temperature range, the braking by the brake mechanism can be suppressed and the occurrence of the fade phenomenon can be prevented by implementing the forced discharge and the regeneration control. As a result, it is possible to reliably prevent the overheat of the brake while suppressing the deterioration of the battery and the deterioration of the electricity cost.

  (2) A control device of an electric vehicle according to this application example, in the above (1), the regeneration control for acquiring the regenerative braking force that can be generated by the regenerative braking control unit according to the charge amount of the drive battery. The braking control unit further includes: a power acquisition unit; and a regeneration execution situation estimation unit that estimates and determines a situation where the regeneration control by the regenerative braking control unit can not be performed based on the charge amount and the regenerative braking force. The braking control is performed when the regeneration execution situation estimation unit estimates a situation in which the regeneration control can not be performed.

  That is, the braking control unit can determine the situation where the forced discharge control should be performed more accurately by performing the braking control after estimating and judging the situation where the regenerative control can not be performed.

  (3) A control device of an electric vehicle according to the application example, the above (1) or (2) further includes a slope information acquisition unit for acquiring slope information of a road surface on which the vehicle is traveling; The control unit implements the braking control when the vehicle travels on a predetermined continuous downhill from the gradient information acquired by the gradient information acquisition unit.

  That is, based on the gradient information, by performing the above-mentioned braking control when the vehicle is traveling on a predetermined continuous downhill, the situation where the forced discharge control should be performed is more accurately taken into consideration in consideration of the traveling conditions. It can be judged.

  (4) A control device for an electric vehicle according to this application example, in any one of the above (1) to (3), the braking control unit performs the forced discharge control and the regeneration control in the braking control. In the case where the braking force is insufficient only by the regenerative braking, the braking by the brake mechanism is also performed. Thereby, more reliable braking of the vehicle can be realized.

  (5) A control device for an electric vehicle according to this application example, in any one of the above (1) to (4), the auxiliary device includes a PTC heater mounted on the vehicle, an electric compressor, and a radiator fan. At least one is included. Efficient forced discharge control can be performed by using, for the forced discharge control, a motor accessory that consumes a large amount of power, such as a PTC heater.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram which shows the structure of the electric vehicle in one Embodiment of this invention. It is a block diagram showing composition of a control device of electric vehicles in one embodiment of the present invention. It is a flowchart which shows the braking control routine which a braking control part performs.

  Hereinafter, an embodiment of the present invention will be described based on the drawings.

  FIG. 1 shows a schematic configuration diagram of an electric vehicle according to an embodiment of the present invention, and the configuration of the electric vehicle according to the present embodiment will be described below based on the drawing.

  A vehicle 1 shown in FIG. 1 is, for example, an electric truck, and a traveling motor 2 is mounted as a power source. The traveling motor 2 is electrically connected to a battery 4 (driving battery) through an inverter / converter (hereinafter simply referred to as an inverter) 3. Further, the output shaft of the traveling motor 2 is connected to the left and right driving wheels 6 via a differential mechanism 5.

  In the vehicle 1 configured as described above, the traveling motor 2 generates a driving force using the power stored in the battery 4, and the driving force is transmitted to the left and right driving wheels 6 via the differential mechanism 5. Run by.

  In addition, at the time of deceleration of the vehicle 1 or traveling on a downhill road (during regenerative traveling), the traveling motor 2 operates as a generator (regeneration driving) by reverse driving from the driving wheel 6 side. Thereby, the electric power generated by the traveling motor 2 is charged to the battery 4 through the inverter 3 as regenerative electric power, and the power generation load of the traveling motor 2 acts on the drive wheels 6, 6 as regenerative braking force (regenerative braking) .

  Further, each wheel of the vehicle 1 including the driving wheel 6 is provided with a brake mechanism 7 that generates a braking force by friction. Specifically, the brake mechanism 7 is, for example, a disk brake or a drum brake, and has a predetermined appropriate temperature range. The predetermined appropriate temperature is, for example, a temperature range in which the fading phenomenon does not occur, and the upper limit value corresponds to the temperature at which the fading phenomenon starts.

  In addition, the vehicle 1 is equipped with an electric auxiliary machine 8 such as a PTC heater, an electric compressor, a radiator fan, etc. which is used in a cooling device for the air conditioner in the car, the traveling motor 2, the inverter 3 and the battery 4. . The electric accessory 8 is connected to the battery 4 and driven by the power of the battery 4.

  Each part of the vehicle 1 configured in this manner is connected to the control device 10 mounted on the vehicle 1.

  FIG. 2 shows a block diagram of a control device for an electric vehicle according to an embodiment of the present invention. The configuration of the control device 10 will be described below based on the figure. The control device 10 is a control circuit for integrally controlling the entire vehicle, and in the present embodiment, a function of a control portion related to braking will be mainly described.

  The control device 10 includes a braking control unit 11 that comprehensively controls the braking of the vehicle 1. The brake control unit 11 is connected to the charge amount acquisition unit 12, the brake temperature acquisition unit 13, the regenerative braking force acquisition unit 14, the regeneration execution state estimation unit 15, the gradient information acquisition unit 16, and the vehicle speed information acquisition unit 17. Various information is input from each part. The brake control unit 11 is connected to the brake mechanism 7, the regenerative braking control unit 18, and the forced discharge control unit 19, and can output a signal to control these units. Not only the braking control unit 11 but also each of these units can mutually transmit information. Further, the braking control unit 11 has a time counting function using information of a timer included in the control device 10, and can measure, for example, a traveling time or a stopping time of a vehicle.

  Specifically, the charge amount acquisition unit 12 is connected to the battery 4 and has a function of acquiring the charge amount (charge amount E) of the battery 4.

  The brake temperature acquisition unit 13 has a function of acquiring the brake temperature (brake temperature Tb) of the brake mechanism 7. The brake temperature may be obtained directly by a sensor or the like, or may be estimated from, for example, the brake pressure and the vehicle speed.

  The regenerative braking force acquisition unit 14 has a function of calculating and acquiring a braking force that can be generated by the traveling motor 2 according to the charge amount of the battery 4.

  The regeneration execution state estimation unit 15 has a function of estimating and determining a state where the regeneration control by the traveling motor 2 can not be performed based on the charge amount of the battery 4 and the regenerative braking force. The situation where the regeneration control can not be performed is, for example, the case where the charge amount of the battery 4 becomes equal to or more than the upper limit value (first charge amount E1) when the regeneration control is continued. On the other hand, the regeneration execution status estimation unit 15 may also have a function of estimating and determining a status where regeneration control can be performed. The situation where the regeneration control can be performed is, for example, the case where the charge amount of the battery 4 (the second charge amount E2) that can perform sufficient regeneration control is obtained.

  The gradient information acquisition unit 16 has a function of acquiring, for example, information (gradient θ) of the road surface gradient detected by a gradient sensor (not shown).

  The vehicle speed information acquisition unit 17 has a function of acquiring vehicle speed information (vehicle speed V) detected by a vehicle speed sensor (not shown), for example.

  The regenerative braking control unit 18 has a function of performing regenerative control to cause the vehicle to perform regenerative braking while charging the battery 4 with regenerative electric power by regeneratively driving the traveling motor 2.

  The forced discharge control unit 19 has a function of performing forced discharge control to reduce the charge amount of the battery 4 by driving the motor auxiliary device 8.

  The braking control unit 11 controls the braking mechanism 7, the regenerative braking control unit 18, and the forced discharge control unit 19 so as to prevent the overheat of the brake 4 while suppressing the deterioration of the battery 4 and the deterioration of the electricity cost based on the information from each unit. Take control.

  The flowchart which shows the damping | braking control routine which the damping | braking control part 11 performs by FIG. 3 is shown, Hereinafter, damping | braking control is demonstrated along the same flowchart.

  First, at step S1, the braking control unit 11 determines whether the charge amount E acquired by the charge amount acquisition unit 12 is equal to or greater than the first charge amount E1. The first charge amount E1 is a variable value, and is set by the regeneration execution status estimation unit 15 to a charge amount corresponding to a situation where the regeneration control can not be performed. If the determination result is true (Yes), that is, if the charge amount E of the battery 4 is in a state of full charge or near full charge, the process proceeds to the next step S2.

  In step S2, the braking control unit 11 determines whether the vehicle speed V acquired by the vehicle speed information acquisition unit 17 is equal to or higher than a predetermined vehicle speed V1. The predetermined vehicle speed V1 is set to a speed at which the necessity for assisting braking is high by braking means other than the brake mechanism 7 such as regenerative braking, and is preferably set according to the vehicle weight, the brake performance, and the like. If the determination result is true (Yes), that is, if the braking assistance is required, the process proceeds to the next step S3.

  In step S3, the braking control unit 11 determines whether the gradient θ acquired by the gradient information acquisition unit 16 is equal to or less than a predetermined gradient θ1. The predetermined gradient θ1 is, for example, a downward gradient that can be regeneratively controlled. In addition, in step S3, a temporal factor may be added to determine whether or not the state of being less than or equal to the predetermined gradient θ1 continues for a predetermined time. If the determination result is true (Yes), that is, if the vehicle 1 is traveling on a downhill road having a predetermined gradient θ1 or less, the process proceeds to the next step S4.

  In step S4, the brake control unit 11 determines whether the brake temperature T acquired by the brake temperature acquisition unit 13 is equal to or higher than the upper limit value Tmax of the appropriate temperature range. If the determination result is true (Yes), that is, if the brake temperature T exceeds the upper limit value, the process proceeds to step S5.

  In step S5, the braking control unit 11 causes the forcible discharge control by the forcible discharge control unit 19 and causes the regenerative control by the regenerative braking control unit 18. That is, the amount of charge of the battery 4 is reduced by the motor auxiliary device 8 under the forced discharge control to make an allowance in the amount of charge, and the vehicle 1 is braked by regenerative braking when braking is necessary.

  Subsequently, in step S6, the braking control unit 11 determines that the charge amount E acquired by the charge amount acquisition unit 12 is smaller than the second charge amount E2, and the brake temperature T acquired by the brake temperature acquisition unit 13 again. Is determined to be smaller than a first brake temperature T1 which is a predetermined temperature. The second charge amount E2 is a value lower than the first charge amount E1, and is set to a charge amount corresponding to a state where the regeneration control can be performed, for example, by the regeneration execution state estimation unit 15.

  If the determination result is false (No), that is, if the charge amount of the battery 4 is still high or the brake temperature is high, the process proceeds to step S7.

  In step S7, the brake control unit 11 determines again whether the brake temperature T acquired by the brake temperature acquisition unit 13 is smaller than a second brake temperature T2 which is a predetermined temperature. The second brake temperature T2 is lower than the first brake temperature, and is set to a temperature at which the brake mechanism 7 can be sufficiently used. If the determination result is false (No), the process proceeds to the next step S8.

  In step S8, the braking control unit 11 determines whether or not the time (stop time) after the vehicle 1 has stopped is equal to or longer than a predetermined stop time. If the determination result is false (No), that is, if the vehicle 1 is traveling or is in a state immediately after stopping, there is a low possibility that the brake temperature decreases, and the process returns to step S5. Continue forced discharge control and regenerative control.

  On the other hand, after the forced discharge control and regeneration control in step S5 are started, if any of the determination results in steps S6 to S8 becomes true (Yes), that is, if any of the conditions in steps S6 to S8 is satisfied, Proceed to step S9.

  In step S9, the braking control unit 11 cancels simultaneous implementation of forced discharge control and regeneration control, and returns the routine.

  If any of the determination results in steps S1 to S4 is false (No), that is, if all the conditions in steps S1 to S4 are not satisfied, the braking control unit 11 performs the forced discharge control in step S5. The routine returns without performing simultaneous execution of regenerative control and regeneration control. That is, the braking by the brake mechanism 7 can be performed at least until the brake temperature reaches the predetermined temperature (upper limit Tmax).

  By performing the above-described braking control, for example, when the vehicle 1 decelerates on the continuous downhill, the braking by the brake mechanism 7 is utilized until the brake temperature reaches the predetermined temperature (upper limit Tmax). Thus, it is possible to avoid a situation where the battery 4 is forcibly discharged by the motor-aided device and the regenerative charging is frequently repeated. On the other hand, when the brake temperature becomes equal to or higher than the predetermined temperature (upper limit value Tmax), the braking by the brake mechanism 7 can be suppressed and the occurrence of the fading phenomenon can be prevented by implementing the forced discharge and the regeneration control.

  Thus, the control device 10 can reliably prevent the brake overheating while suppressing the deterioration of the battery 4 and the deterioration of the power cost.

  In addition, the braking control unit 11 performs the determination of the charge amount in step S1 based on the first charge amount E1 which is determined by the regeneration execution state estimation unit 15 to estimate the situation where the regeneration control can not be performed. The situation in which control should be implemented can be determined more accurately.

  Furthermore, the braking control unit 11 determines that the vehicle is traveling on a predetermined continuous downhill road in step S3 so as to consider the traveling condition of the vehicle 1 more, and to perform the forced discharge control. Can be determined more accurately.

  This completes the description of the embodiments of the present invention, but the aspects of the present invention are not limited to this embodiment.

  For example, when the forced discharge control and the regeneration control in step S5 of the above embodiment are performed, the braking by the brake mechanism 7 may also be performed if the braking force is insufficient only by the regenerative braking. Thereby, more reliable braking of the vehicle can be realized.

  Further, in the above-described embodiment, the motor-driven accessory used in the forced discharge control is a PTC heater, a motor-driven compressor, or a radiator fan, but at least one of them may be included. Efficient forced discharge control can be performed by using, for the forced discharge control, a motor accessory that consumes a large amount of power, such as a PTC heater.

  Further, in the above embodiment, each threshold value such as the predetermined vehicle speed V1, the predetermined slope θ1, the first brake temperature T1, the second brake temperature T2 may be a fixed value, and the vehicle and the brake mechanism It may be a value that fluctuates according to the specification or the situation of the

  Moreover, in the said embodiment, although the vehicle 1 is an electric truck, a vehicle type is not limited and a common passenger car, a bus, etc. may be sufficient.

1 vehicle 2 drive motor 3 inverter 4 battery (drive battery)
5 differential mechanism 6 driving wheel 7 brake mechanism 10 control device 11 brake control unit 12 charge amount acquisition unit 13 brake temperature acquisition unit 14 regenerative braking force acquisition unit 15 regeneration execution state estimation unit 16 gradient information acquisition unit 17 vehicle speed information acquisition unit 18 regeneration Braking control unit 19 Forced discharge control unit

Claims (5)

A control device for a vehicle equipped with a drive battery for supplying power to a traveling motor,
A regenerative braking control unit that performs regenerative control to cause the vehicle to generate regenerative braking while charging the driving battery with regenerative electric power by regeneratively driving the traveling motor;
A brake mechanism having a predetermined proper temperature range and causing the vehicle to generate a braking force;
A forced discharge control unit that implements forced discharge control that forcibly lowers the charge amount of the driving battery by driving an accessory mounted on the vehicle;
A brake temperature acquisition unit that acquires a brake temperature of the brake mechanism;
A charge amount acquisition unit that acquires the charge amount of the driving battery;
A braking control unit that controls the regenerative braking control unit, the brake mechanism, and the forced discharge control unit;
Including
The braking control unit performs braking control as
If the brake temperature is within the appropriate temperature range, the brake mechanism is braked;
The control device for an electric vehicle, wherein the forced discharge control by the forced discharge control unit and the regenerative control by the regenerative braking control unit are performed when the brake temperature is higher than the upper limit value of the appropriate temperature range. A regenerative braking force acquisition unit that acquires a regenerative braking force that can be generated by the regenerative braking control unit according to the charge amount of the drive battery;
The system further includes a regeneration execution situation estimation unit that estimates and determines a situation in which the regeneration control by the regeneration braking control unit can not be performed based on the charge amount and the regeneration braking force.
The control device according to claim 1, wherein the braking control unit implements the braking control when the regeneration execution situation estimation unit estimates a situation in which the regeneration control can not be performed. The system further includes a gradient information acquisition unit that acquires gradient information of the road surface on which the vehicle is traveling,
The control according to claim 1 or 2, wherein the braking control unit implements the braking control when the vehicle travels on a predetermined continuous downhill from the gradient information acquired by the gradient information acquiring unit. apparatus.   4. The braking control unit according to claim 1, wherein, when the forced discharge control and the regeneration control are performed in the braking control, the braking mechanism is also performed when the braking force is insufficient only with regenerative braking. The control apparatus of the electrically-driven vehicle as described in any one.   The control device for an electric vehicle according to any one of claims 1 to 4, wherein the auxiliary device includes at least one of a PTC heater, an electric compressor, and a radiator fan mounted on the vehicle.

Images