JP2018011488A - Electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress electrical power consumption in regenerative control to improve electricity economy.SOLUTION: When a prescribed regenerative electric power (required regenerative electric power) in regenerative operation of a vehicle 1 is lower than a regenerative capability of a front motor 3 and a running state of the vehicle 1 does not become unstable, the driving of a rear inverter 13 for supplying electric power to a rear motor 7 is stopped to inhibit electrical power consumption of an inverter in regenerative operation.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electric vehicle that transmits driving force to a front wheel and a rear wheel by a driving motor.

  In recent years, vehicles (EV) in which driving wheels are driven by a traveling motor, and hybrid vehicles in which a traveling motor and an engine are combined to obtain the driving force of the vehicle have been developed and put into practical use. As a hybrid vehicle, not only a vehicle (HEV) that charges a battery that generates electricity by driving a generator by an engine and supplies power to a traveling motor (HEEV), but also a vehicle (PHEV) that can be charged by an external commercial power source. Development and practical use are progressing.

  In such an electric vehicle, various techniques have been proposed in which the front and rear wheels are driven by separate driving motors (4WD vehicles) and the driving force of the front and rear wheels is distributed according to the driving state. In a 4WD vehicle, the distribution of the driving force between the front wheels and the rear wheels is normally set to a predetermined ratio, and the distribution of the driving force is changed according to the running state (see Patent Document 1). By distributing the driving force according to the traveling state, the traveling stability can be improved without reducing the power consumption.

  By the way, for example, when the electric vehicle is traveling at a reduced speed with the accelerator pedal released or coasting, the traveling motor receives the energy from the drive wheels. Thereby, electric energy (regenerative electric power) is generated and predetermined braking force (regenerative braking force) is obtained (regenerative control).

  When regenerative control is performed, desired regenerative power (predetermined regenerative power) is obtained according to the traveling state of the vehicle, and electric energy is generated by both the front and rear motors to obtain the predetermined regenerative power. However, depending on the driving condition of the vehicle, it is conceivable that the predetermined regenerative power can be secured only with the front or rear wheel driving motor, but the current situation is that both the front and rear driving motors obtain the predetermined regenerative power. It is. For this reason, in an electric vehicle in which the front and rear wheels are driven by separate driving motors, there is still room for further improvement in power consumption.

Japanese Patent No. 3776434

  The present invention has been made in view of the above situation, and in an electric vehicle in which front and rear wheels are driven by separate driving motors, an electric vehicle capable of improving power consumption by suppressing power consumption when performing regenerative control is provided. The purpose is to provide.

  In order to achieve the above object, an electric vehicle according to a first aspect of the present invention includes a front motor that transmits driving force to the front wheels of the vehicle, a rear motor that transmits driving force to the rear wheels of the vehicle, and electric power from a battery. In an electric vehicle comprising a front inverter for supplying a front motor and a rear inverter for supplying electric power from the battery to the rear motor, a predetermined value during regenerative operation of the vehicle is determined based on a traveling state of the vehicle. Regenerative power deriving means for obtaining regenerative power, and when the predetermined regenerative power obtained by the regenerative power deriving means falls below the regenerative capacity of either the front motor or the rear motor, the front motor, Alternatively, the front inverter that supplies power to the other of the rear motors, or the rear inverter Characterized by comprising an inverter control means for stopping the driving of the motor.

  In the present invention according to claim 1, the predetermined regenerative power (required regenerative power) during the regenerative operation of the vehicle is based on the regenerative capability of either one of the driving motors, that is, the front motor or the rear motor. If it is lower, the driving of the front inverter or the rear inverter for supplying power to one of the other motors is stopped, and the power consumption of the inverter during the regenerative operation is suppressed.

  As a result, in an electric vehicle in which the front and rear wheels are driven by separate travel motors, it is possible to improve power consumption by suppressing power consumption when performing regenerative control.

  The electric vehicle according to a second aspect of the present invention is the electric vehicle according to the first aspect, wherein the inverter control means is configured such that the predetermined regenerative power obtained by the regenerative power deriving means is equal to the regenerative power of the front motor. The driving of the rear inverter that supplies electric power to the rear motor is stopped when the capacity falls below the capacity.

  In the present invention according to claim 2, when the predetermined regenerative power (required regenerative power) during the regenerative operation of the vehicle is lower than the regenerative capacity of the front motor, the driving of the rear inverter for supplying power to the rear motor is stopped. Then, a predetermined regenerative power is obtained only by the front motor. For this reason, power consumption can be suppressed while traveling stability is ensured.

  The electric vehicle according to a third aspect of the present invention is the electric vehicle according to the first aspect, wherein the inverter control means is configured such that the predetermined regenerative power obtained by the regenerative power deriving means is regenerated electric power. The driving of the front inverter or the rear inverter is stopped when the regenerative capacity of either the high-side front motor or the rear motor falls below.

  In the present invention according to claim 3, when the predetermined regenerative power (required regenerative power) during regenerative operation of the vehicle is lower than the regenerative capacity of the motor on the high side, the regenerated power is low The driving of the inverter for supplying electric power to the motor is stopped, and predetermined regenerative power is obtained only by the motor having the higher regenerative power. For this reason, the frequency which stops the drive of an inverter can be raised in the state which ensured predetermined regenerative electric power.

  According to a fourth aspect of the present invention, there is provided an electric vehicle according to the present invention, wherein the electric vehicle according to any one of the first to third aspects detects an element that makes the traveling of the vehicle unstable. And the inverter control means controls to stop driving the front inverter or the rear inverter when the unstable element detecting means detects an element that makes the traveling of the vehicle unstable. It is characterized by not implementing.

  In the present invention according to claim 4, when driving of the vehicle becomes unstable, control for stopping the drive of the inverter is not performed, and regenerative power is obtained by both the front motor and the rear motor (regenerative power in the state of 4WD). To maintain the running stability during the regenerative operation.

  According to a fifth aspect of the present invention, there is provided the electric vehicle according to the fourth aspect, wherein the unstable element detecting unit includes a rain deriving unit for deriving rainfall, a freezing deriving unit for deriving freezing of the road surface, It includes at least one of a turning derivation means for deriving turning traveling and a slip derivation means for deriving wheel slip.

  In the present invention according to claim 5, rain is derived by a sensor for detecting raindrops, a sensor for detecting the operation of the wiper, etc. (rainfall deriving means), and freezing of the road surface is derived by an outside temperature sensor or the like (freezing deriving means). Deriving the turning of the vehicle with a sensor that detects the steering angle of the steering wheel (turning derivation means), and the wheel speed sensor that detects the front and rear wheel speed, the acceleration sensor that detects the acceleration of the vehicle, etc. (Slip derivation means), it can be determined that the running of the vehicle is unstable.

  The electric vehicle according to the present invention can improve power consumption by suppressing power consumption when performing regenerative control in an electric vehicle in which front and rear wheels are driven by separate driving motors.

It is a block diagram showing the whole concept of the electric vehicle which concerns on one Example of this invention. It is a block block diagram of the control apparatus of the electric vehicle which concerns on one Example of this invention. It is a flowchart of the regeneration control of the electric vehicle which concerns on one Example of this invention. It is a flowchart of the regeneration control of the electric vehicle which concerns on one Example of this invention.

  The configuration of the electric vehicle will be described with reference to FIGS. 1 and 2. FIG. 1 shows a schematic configuration for conceptually explaining the entire electric vehicle according to one embodiment of the present invention, and FIG. 2 shows a block configuration of a control device for the electric vehicle according to one embodiment of the present invention.

  As shown in FIG. 1, an electric vehicle (vehicle) 1 is provided with a front motor 3 that gives (transmits) driving force to a front wheel 2, and the front motor 3 is connected to an axle 5 of the front wheel 2 via a front differential 4. Has been. Further, a rear motor 7 that applies (transmits) driving force to the rear wheel 6 is provided, and the rear motor 7 is connected to an axle 9 of the rear wheel 6 via a rear differential 8.

  Although not shown in the drawing, for example, the axle 5 of the front wheel 2 is provided with an engine to which an output shaft is connected via a clutch, and a generator is driven by the engine and power is applied to the axle 5. It is like that.

  The vehicle 1 is equipped with a battery 11 in which a large number of battery cells are accommodated. A front motor 3 is connected to the battery 11 via a front inverter 12, and a rear motor 7 is connected via a rear inverter 13. Electric power according to the operation of the passenger's accelerator pedal is supplied from the battery 11 to the front motor 3 and the rear motor 7 via the front inverter 12 and the rear inverter 13.

  Although specifically described later, various information for power running operation and regenerative operation are input from the control device 15 to the front inverter 12 and the rear inverter 13, and the motor voltage is input to the front inverter 12 and the rear inverter 13. The motor rotation speed is set, and the inverter drive unit and the motor drive unit are controlled. That is, the front inverter 12 and the rear inverter 13 are driven based on information from the control device 15, and the front motor 3 and the rear motor 7 are driven and controlled to a predetermined state.

  The axle 5 is provided with a vehicle speed sensor 21, and the accelerator pedal is provided with an accelerator position sensor 22. The brake pedal is provided with a brake sensor 23, and the front wheel 2 and the rear wheel 6 are provided with wheel speed sensors 24. Further, the handle 25 is provided with a handle angle sensor 26 and a selection switch 27 for selecting a regenerative braking force of an arbitrary strength from a plurality of braking forces.

  Further, the vehicle 1 is provided with a power switch 29 that switches a state of a power source for driving the vehicle 1. The vehicle 1 is also provided with an outside air temperature sensor 32, a shift position sensor 31, and a wiper switch 33.

  The control device 15 includes vehicle speed information detected by the vehicle speed sensor 21, information on the amount of depression of the accelerator pedal detected by the accelerator position sensor 22, information on the depression state of the brake pedal detected by the brake sensor 23, and a selection switch 27. The selection information of the regenerative braking force detected at is input. Further, the control device 15 receives information on the electric system (power supply status) for driving the vehicle 1 detected by the power switch 29 and information on the operation mode detected by the shift position sensor 31.

  Further, the control device 15 receives information on the difference between the wheel speeds of the front and rear wheels detected by the wheel speed sensor 24 (slip derivation means) (acceleration information by the acceleration sensor if necessary), and slips the vehicle 1. The situation is judged. Further, information on the steering wheel angle detected by the steering wheel angle sensor 26 (turning derivation means) is input to the control device 15, and the turning state of the vehicle 1 is determined.

  Further, the control device 15 receives information on the outside air temperature detected by the outside air temperature sensor 32 (freezing derivation means), and determines the frozen state of the road surface. Further, the operation information of the wiper detected by the wiper switch 33 (rainfall deriving means) is input to the control device 15 to detect the rain condition. In addition, as the rain deriving means, it is possible to use a sensor that directly detects rain, such as a raindrop sensor.

  Based on the detection information of the wheel speed sensor 24, the steering wheel angle sensor 26, the outside air temperature sensor 32, and the wiper switch 33, it is determined whether there is an element that makes the traveling of the vehicle 1 unstable (unstable element detection means).

  As shown in FIG. 2, the control device 15 includes an information reception calculation unit 16 and receives information from various sensors. The information reception calculation unit 16 determines the operation mode (drive D, reverse R, first gear L, etc.), power running / regenerative operation, and calculates the front and rear wheel drive distribution (power running, regenerative operation). When regenerative operation is determined, regenerative power (required predetermined regenerative power) is set according to the traveling state of the vehicle 1 (regenerative power deriving means).

  In addition, the control device 15 includes an information transmission unit 17, and the information transmission unit 17 performs drive control of the front inverter 12 and torque control of the front motor 3 based on the information determined and calculated by the information reception calculation unit 16. The driving signal is transmitted to the front inverter 12. In the front inverter 12, the voltage and rotation speed of the front motor 3 are set based on the transmitted information, and the driving of the front inverter 12 and the front motor 3 is controlled.

  The information transmission unit 17 performs drive control of the rear inverter 13 and torque control of the rear motor 7 based on the information determined and calculated by the information reception calculation unit 16, and transmits a drive signal to the rear inverter 13. In the rear inverter 13, the voltage and rotational speed of the rear motor 7 are set based on the transmitted information, and the driving of the rear inverter 13 and the rear motor 7 is controlled.

  Information of the front inverter 12 and the rear inverter 13 is fed back to the information reception calculation unit 16, and the determined and calculated information is corrected.

  In the vehicle 1 described above, when the power running / regenerative operation is determined based on the information of various sensors, the set operation mode, and the like, and the power running operation and the regenerative operation are determined, the front motor in each operation is determined by the drive distribution calculation. 3 and the drive distribution of the rear motor 7 are set. For example, when the capabilities of the front motor 3 and the rear motor 7 are the same, the drive distribution is set to 50:50.

  In the control device 15 described above, when the regenerative operation is determined, the predetermined regenerative power set according to the traveling state of the vehicle 1 and the regenerative capability of the front motor 3 are compared. As a result of the comparison, when the predetermined regenerative power is less than the regenerative capacity of the front motor 3, that is, when it is determined that the predetermined regenerative power can be obtained only by the regenerative operation of the front motor 3 during the regenerative operation, The drive is stopped (inverter control means).

  For this reason, when the predetermined regenerative power is obtained only by the regenerative operation of the front motor 3, only the front motor 3 is driven to obtain the regenerative power (regenerative braking force is obtained). As a result, it is possible to suppress a decrease in traveling stability to a minimum (the driving stability is not impaired because the front motor 3 is driven), and it is possible to suppress the power consumption of the inverter during the regenerative operation, In the vehicle 1 in which the front and rear wheels are driven by separate driving motors, it is possible to suppress power consumption when performing regenerative control and improve power consumption.

  If the predetermined regenerative power is compared with the regenerative capacity of the rear motor 7, and it is determined that the predetermined regenerative power can be obtained only by the regenerative operation of the rear motor 7, the drive of the front inverter 12 is stopped to suppress the power consumption. Is also possible.

  Also, if the regenerative capabilities of the front motor and rear motor are different, the specified regenerative power is compared with the regenerative capability of the motor with the higher regenerative capability, and the predetermined regenerative power can be obtained only by the regenerative operation of the motor with the higher regenerative capability. In such a case, it is also possible to stop the drive of the inverter of the motor having the low regeneration capacity. In this case, it is possible to increase the frequency at which the drive of the inverter is stopped in a state where the predetermined regenerative power is secured.

  Based on FIG. 3 and FIG. 4, the flow of control for stopping the drive of the rear inverter 13 during the regenerative operation will be specifically described.

  As shown in FIG. 3, in step S1, various information (sensor information and the like) is read, and in step S2, the power switch 29 is turned on to determine whether or not the vehicle 1 is ready to travel (power on). To be judged. If it is determined in step S2 that the power is on, it is determined in step S3 whether or not the shift position is in the travel range (D range). If it is determined in step S2 that the power is not on, the process proceeds to step S1.

  If it is determined in step S3 that the shift position is in the D range, it is determined in step S4 whether the vehicle speed is equal to or less than a predetermined value (hkm / h). If it is determined in step S4 that the vehicle speed is equal to or less than the predetermined value (hkm / h), it is determined in step S5 whether or not the accelerator opening is equal to or less than the predetermined opening S. In step S5, the accelerator opening is determined to be the predetermined opening. If it is determined that it is equal to or less than S, the process proceeds to step S6.

  That is, it is determined whether or not the accelerator pedal is in a decelerating state, and if it is determined that the accelerator pedal is in a decelerating state, it is determined that a regenerative brake is generated, and the process proceeds to step S6. .

  If it is determined in step S4 that the vehicle speed exceeds the predetermined value (hkm / h), and if it is determined in step S5 that the accelerator opening exceeds the predetermined opening S, it is not in a state of generating regenerative braking. The process proceeds to step S1.

  In step S6, the regenerative power per unit time (predetermined regenerative power) obtained (set) according to the running state of the vehicle 1 is the regenerative capacity P (maximum regenerative power that can be generated) of the front motor 3. It is determined whether or not: If it is determined that the predetermined regenerative power is less than or equal to the regenerative capability P of the front motor 3, the necessary regenerative power can be obtained only by driving the front motor 3, and the process proceeds to step S7. If it is determined that the predetermined regenerative power exceeds the regenerative capability P of the front motor 3, the necessary regenerative power cannot be obtained by driving the front motor 3 alone, and the process proceeds to step S1.

  Step S7 is a routine for determining an element that may cause the traveling of the vehicle 1 to become unstable. Specifically, it is determined whether or not there is an element that causes slip in the vehicle 1. The process of step S7 will be described based on FIG.

  As shown in FIG. 4, it is determined in step S21 whether or not the wiper switch 33 is OFF. If it is determined that the wiper switch 33 is OFF, it is determined that it is not raining, and the outside air temperature sensor 32 is determined in step S22. It is determined whether or not the outside air temperature that is the detection information is T ° C. or higher. If it is determined in step S22 that the outside air temperature is equal to or higher than T ° C, it is determined that there is no possibility of freezing the road surface, and the process proceeds to step S23.

  In step S23, it is determined whether or not the handle angle, which is detection information of the handle angle sensor 26, is equal to or smaller than θ. If it is determined that the handle angle is equal to or smaller than θ, it is determined that there is no possibility of a sudden turn, and in step S24. It is determined whether or not the wheel speed difference (absolute value) between the front and rear wheels, which is detection information of the wheel speed sensor 24, is R or less. If it is determined in step S24 that the wheel speed difference (absolute value) is equal to or less than R, it is determined that no slip has occurred in the wheel, and it is determined in step S25 that there is no unstable element with respect to the traveling of the vehicle 1 and the end. It becomes.

  If it is determined in step S21 that the wiper switch 33 is not OFF, it is determined that there is a possibility of slipping because the road surface is wet due to rain, and if the outside air temperature is determined to be lower than T ° C in step S22. It is determined that there is a possibility that the road surface will freeze and slip. Further, if it is determined in step S23 that the steering wheel angle exceeds θ, it is determined that there is a risk of sudden turning, and if it is determined in step S24 that the wheel speed difference exceeds R, the wheel is slipping. It is judged.

  In these cases, there is a possibility of slipping due to rain, road surface freezing, or sudden turning, and it is determined that slip actually occurs, and it is determined in step S26 that there is an unstable element with respect to traveling of the vehicle 1. And end. In the illustrated example, when any one of the determinations from step S21 to step S24 is determined to be negative, it is determined in step S26 that there is an unstable element, but any one or more or all of them are determined. If NO is determined, it may be determined in step S26 that there is an unstable element.

  Returning to the flowchart of FIG. 3, after an unstable element is determined in step S7, it is determined in step S8 whether there is an unstable element. If it is determined in step S8 that there are no unstable elements, a state in which predetermined regenerative power can be obtained only by the regenerative operation of the front motor 3 and there is no element that makes the traveling of the vehicle 1 unstable. Therefore, in step S9, the drive distribution of the front motor 3 and the rear motor 7 is set to 100: 0, the drive of the rear inverter 13 is stopped, and a return is made.

  If it is determined in step S8 that there is no unstable element, that is, there is an unstable element (possibility of slipping), the driving of the vehicle 1 may not be stabilized by driving the front motor 3 alone. Transition to processing. Thereby, the drive of the rear inverter 13 is not stopped, the drive by the front motor 3 and the rear motor 7 is continued, and the running stability of the vehicle 1 is maintained.

  That is, when the predetermined regenerative power (required regenerative power) during the regenerative operation of the vehicle 1 is lower than the regenerative capability of the front motor 3 and the vehicle 1 does not become unstable, power is supplied to the rear motor 7. Therefore, the driving of the rear inverter 13 can be stopped, and the power consumption of the inverter during the regenerative operation can be suppressed.

  In the above-described electric vehicle, in the vehicle 1 in which the front and rear wheels are driven by the front motor 3 and the rear motor 7, it is possible to suppress power consumption when performing regenerative control and improve power consumption.

  When the predetermined regenerative power (required regenerative power) during the regenerative operation of the vehicle 1 is lower than the regenerative capacity of the front motor 3, the predetermined regenerative power is obtained only by the front motor 3. Power consumption can be suppressed in a state in which

  Further, when an element (slip) that makes the traveling of the vehicle 1 unstable is detected, the control for stopping the driving of the rear inverter 13 is not performed. Therefore, when the traveling of the vehicle 1 becomes unstable, the front motor 3, Regenerative electric power is obtained by both of the rear motors 7 (regenerative power is obtained in a 4WD state), and the running stability during the regenerative operation can be maintained.

  The present invention can be used in the industrial field of electric vehicles.

1 Electric vehicle (vehicle)
2 Front wheel 3 Front motor 4 Front differential 5, 9 Axle 6 Rear wheel 7 Rear motor 8 Rear differential 11 Battery 12 Front inverter 13 Rear inverter 15 Control device 16 Information reception calculation unit 17 Information transmission unit 21 Vehicle speed sensor 22 Acceleration position sensor 23 Brake sensor 24 Wheel speed sensor 25 Handle 26 Handle angle sensor 27 Selection switch 29 Power switch 31 Shift position sensor 32 Outside air temperature sensor 33 Wiper switch

Claims (5)

A front motor that transmits driving force to the front wheels of the vehicle;
A rear motor for transmitting driving force to the rear wheels of the vehicle;
A front inverter for supplying power from a battery to the front motor;
In an electric vehicle comprising a rear inverter for supplying electric power from the battery to the rear motor,
Regenerative power deriving means for obtaining a predetermined regenerative power during regenerative operation of the vehicle based on the traveling state of the vehicle;
When the predetermined regenerative power obtained by the regenerative power deriving means falls below the regenerative capacity of either the front motor or the rear motor, power is supplied to either the front motor or the rear motor. An electric vehicle comprising: the front inverter for supplying the inverter; or inverter control means for stopping driving of the rear inverter. The electric vehicle according to claim 1,
The inverter control means includes
The electric vehicle characterized in that when the predetermined regenerative power obtained by the regenerative power deriving means falls below the regenerative capacity of the front motor, the driving of the rear inverter that supplies power to the rear motor is stopped. The electric vehicle according to claim 1,
The inverter control means includes
When the predetermined regenerative power obtained by the regenerative power deriving means falls below the regenerative capacity of either the front motor or the rear motor on the side where the regenerated power is high, the front inverter, or An electric vehicle characterized in that driving of the rear inverter is stopped. In the electric vehicle according to any one of claims 1 to 3,
Comprising an unstable element detecting means for detecting an element that makes the running of the vehicle unstable;
The inverter control means includes
An electric vehicle characterized in that control for stopping driving of the front inverter or the rear inverter is not performed when the unstable element detecting means detects an element that makes traveling of the vehicle unstable. The electric vehicle according to claim 4,
The unstable element detecting means includes
An electric vehicle characterized by including at least one of rainfall deriving means for deriving rainfall, freezing deriving means for deriving road surface freezing, turning deriving means for deriving turning, and slip deriving means for deriving wheel slip .

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