JPH0799704A - Power controller for electric vehicle - Google Patents

Abstract

PURPOSE:To ensure constant braking force at all times without regenerative resistance while securing required regenerative braking force even when a battery is brought to a state close to sufficient charging when an accelerator is stepped off and a brake pedal is worked. CONSTITUTION:The depth of discharge of a battery 7 is detected when an accelerator pedal 5 is returned, a first motor 9 and a second motor 10 are regeneratively operated when the battery 7 can be charged, and the battery 7 is charged by regenerative power obtained by the regenerative operation. When the battery 7 cannot be charged, either of the first motor 9 or the second motor 10 is regeneratively operated, another motor of the first motor 9 or the second motor 10 is made to power-run by regenerative power acquired by the regenerative operation, and regenerative braking is applied without charging to the battery 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power control device for an electric vehicle, which is mounted on an electric vehicle having a plurality of coaxially arranged motors as a power source and drives the motors to perform power running and regenerative braking.

[0002]

2. Description of the Related Art As a power control device for an electric vehicle for controlling a motor of the electric vehicle, there has been heretofore known JP-A-61-1477.
A "regenerative braking device for an electric vehicle" disclosed in Japanese Patent Application No. 43 (Japanese Patent Application No. 59-269358) is known.

FIG. 8 is a block diagram showing a configuration example of the regenerative braking device for an electric vehicle disclosed in the above publication.

The regenerative braking device 201 shown in this figure has a regenerative braking command generator 202 which outputs a regenerative braking command when the speed of the electric vehicle is reduced, a battery 203 which is a power source of the electric vehicle, and a power running command. When entered,
A motor 205, which is a power source of the electric vehicle, is driven to run by using the battery 203 as a power source, and the regenerative braking command generator 2
When a regenerative braking command is output from 02, the motor 205
The controller 204 that regeneratively brakes the battery 203 and charges the battery 203 with the regenerative electric power obtained by the regenerative braking, the load device 206 whose one end is connected to one end of the battery 203, and the terminal voltage of the battery 203 are detected to detect the voltage. A voltage detector 207 that outputs a detection signal V,
When the regenerative braking command is output from the regenerative braking command generator 202 and the value of the voltage detection signal V output from the voltage detector 207 is larger than the preset reference voltage V _ref , the other end of the load device 206 Is connected to the other end of the battery 203 to prevent the battery 203 from being overcharged by consuming the regenerative electric power regenerated by the controller 204.

Then, when the accelerator pedal of the electric vehicle is depressed and a power running command is input, the controller 2
Based on the electric power of the battery 203 by 04, the motor 205 is made to perform a power running operation to drive the electric vehicle, and the accelerator pedal is returned to regenerative braking command generator 202.
When the regenerative braking command is output from the controller 20,
4, the motor 205 is regeneratively braked, and if the discharge depth of the battery 203 is large at this time,
The battery 2 uses the regenerative power obtained by the regenerative braking operation.
If the depth of discharge of the battery 203 is small, the regenerative electric power obtained by the regenerative braking operation is consumed by the load device 206 and released as heat to the outside.

[0006]

However, in the above-described conventional power control device for an electric vehicle, the battery 203 is fully charged so that a constant regenerative braking force can be obtained even when the battery 203 is fully charged. In the charging state, the regenerative electric power obtained by the regenerative braking operation is consumed by the load device 206. Therefore, for an electric vehicle that is originally desired to be lightweight, a large and heavy load device,
For example, there is a problem that the load device 206 of several tens of kW class and several tens of kg class must be mounted.

Therefore, as a method of solving such a problem, it may be considered that the motor 205 consumes a part of the regenerative electric power obtained when the motor 205 of the electric vehicle is regeneratively braked.

However, in such a method, as shown in FIG.
As can be seen from the experimental results shown in,
Area where the motor efficiency becomes unstable (unstable area)
Therefore, the efficiency of the motor cannot be reduced to zero.

For this reason, in an electric vehicle equipped with only one motor, regenerative electric power cannot be completely consumed by this motor, and the capacity of the load device can be reduced. There was a problem that it could not be lost.

In view of the above circumstances, the present invention can secure a regenerative braking force according to a pedaling force, a stroke, etc. when the accelerator is turned off or the brake pedal is stepped on, and at the same time, a battery It is possible to control the regenerative power below the maximum regenerative power, which ensures a constant braking force without a load device (hereinafter referred to as regenerative resistance) even when the battery is near full charge. It is an object of the present invention to provide a power control device for an electric vehicle that can do the above.

[0011]

In order to achieve the above-mentioned object, the present invention provides a power control device for an electric vehicle that individually performs a power running operation and a regenerative operation of a plurality of motors mounted on the electric vehicle. When returned, or when the brake pedal is stepped on, the rechargeable electric power obtained by regenerative operation of each motor can be returned to the battery, and the chargeable judgment unit When it is determined that all regenerative power obtained by regenerative operation of each motor can be returned to the battery, regenerative operation of each motor is performed, and regenerative power obtained by this regenerative operation is returned to the battery. If it is not possible to return all the regenerative electric power obtained by regenerative operation of each motor to the battery by the operating unit and the chargeable determination unit. When a predetermined value is reached, a part of each motor is regeneratively operated, and at least a part of the regenerative power obtained by this regenerative operation that cannot be charged to the battery is consumed by the remaining motors. It is characterized by having.

[0012]

In the above structure, when the accelerator pedal is returned or the brake pedal is closed, it is determined whether the rechargeable electric power obtained by regenerative operation of each motor by the chargeability determination unit can be returned to the battery. If it is determined that the rechargeable electric power obtained by regenerative operation of each motor can be returned to the battery by the chargeable determination unit, the regenerative operation of each motor is performed by the full regenerative operation unit. If the regenerative power obtained by this regenerative operation is returned to the battery and it is determined that the rechargeable power obtained by performing regenerative operation of each motor cannot be returned to the battery by the chargeability determination unit, A part of each motor is regenerated by the regenerative operation unit, and at least the battery power of regenerative power obtained by this regenerative operation is used. Amount that can not be returned to the over is to consume the rest of the motor.

[0013]

1 is a block diagram showing an embodiment of a power control apparatus for an electric vehicle according to the present invention.

A power controller 1 for an electric vehicle shown in this figure.
Is a brake pedal 2, a plurality of brake mechanisms 3, an accelerator pedal 5, a regenerative braking force range switching lever 6,
A battery 7 and a control device 8 are provided, and the first and second motors 9 and 10 that are coaxially connected based on the depression amount of the accelerator pedal 5 and the range position of the regenerative braking force range switching lever 6 are highly efficient. Powering operation is performed by excitation or regenerative braking is performed. When the brake pedal 2 is depressed, each brake mechanism 3 is operated by a hydraulic circuit according to the amount of depression to brake each tire 12 connected by the differential gear mechanism 11 to decelerate and stop the electric vehicle.

The brake pedal 2 is depressed when the driver decelerates or stops the electric vehicle to operate the hydraulic circuit, and the brake mechanisms 3 are operated with the strength corresponding to the amount of depression.

Each brake mechanism 3 is provided on each wheel shaft 13 provided in the electric vehicle, and is fixed to each wheel shaft 13 when brake pressure is transmitted through the hydraulic circuit. By pressing a brake pad or the like against the brake disc plate or the like, the rotational force of the corresponding tire 12 is mechanically reduced.

The accelerator pedal 5 is depressed when the driver accelerates the electric vehicle. When the accelerator pedal 5 is depressed by the driver, this is detected by an accelerator switch (not shown). An accelerator command is generated and supplied to the control device 8. When the driver releases the accelerator command, the accelerator switch detects the accelerator command to generate an accelerator off command and supplies it to the control device 8. To do.

Further, the regenerative braking force range switching lever 6 is
It is a lever operated by the driver when switching the magnitude of the regenerative braking force equivalent to conventional engine braking, and generates a braking force range signal according to the position (range position) operated by the driver. Is supplied to the control device 8.

The battery 7 is a direct-current power source configured to be chargeable and dischargeable, and supplies the accumulated power to the control device 8 while taking in the regenerative voltage output from the control device 8 and storing the regenerated voltage. .

When the accelerator pedal 5 is released, the control device 8 detects the accelerator pedal off sensor 14 for generating an accelerator off signal and the voltage across the terminals of the battery 7 (battery voltage) to detect the voltage. A voltage sensor 15 for generating a signal and a current sensor 16 for detecting a current input to and output from the battery 7 to generate a current detection signal.
A rotation sensor 17 for detecting the number of rotations of the first motor 9 and the second motor 10 to generate a rotation detection signal; an accelerator command output from the accelerator switch; and an accelerator off output from the accelerator off sensor 14. signal,
Based on the voltage detection signal output from the voltage sensor 15, the current detection signal output from the current sensor 16, and the rotation detection signal output from the rotation sensor 17, the first and second power running operation commands and the first and second regeneration are performed. The controller 18 for generating an operation command and the like is provided.

Further, the control device 8 takes in a battery voltage (DC voltage) output from the battery 7 when the controller 18 outputs the first power running operation command, and generates an AC drive voltage. The first motor 9 is driven to perform power running, and when the first regenerative operation command is output from the controller 18, the first motor 9 is regeneratively operated to regeneratively brake the tire 12, and regenerative power obtained by this regenerative operation is generated. The first inverter 19 for returning to the battery 7 and charging it, and the second from the controller 18
When the power running operation command is output, the battery voltage (DC voltage) output from the battery 7 is taken in to generate an AC drive voltage to drive the second motor 10 in the power running mode, and the controller 18 outputs the second regenerative operation command. Is output, the second motor 10 is regeneratively operated to regeneratively brake the tire 12, and the regenerative electric power obtained by the regenerative operation is returned to the battery 7 to charge the second inverter 20. There is.

Then, when the accelerator pedal 5 is depressed, the control device 8 having the above-described configuration has first and second alternating currents based on the direct current voltage of the battery 7 according to the amount of depression.
A driving current is generated to drive the first and second motors 9 and 10 to power the electric vehicle. After that, when the accelerator pedal 5 is returned, the depth of discharge of the battery 7 is detected and the battery 7 is charged. When possible, the first motor 9 and the second motor 10 are regeneratively operated, and the battery 7 is charged with the regenerative electric power obtained by this regenerative operation. When the battery 7 cannot be charged, the first motor 9
Alternatively, one of the second motors 10 is regeneratively operated, and the regenerative power obtained by this regenerative operation causes the remaining one of the first motor 9 or the second motor 10 to perform a powering operation, without charging the battery 7. , Apply regenerative braking.

Next, referring to the block diagram shown in FIG. 1 and the flow chart shown in FIG. 2, the regenerative operation operation of this embodiment will be described.

First, when the accelerator pedal 5 is returned and turned off from the state in which the accelerator pedal 8 is depressed, the controller 18 in the control device 8 operates on the basis of the output of the accelerator off sensor 14. Is detected and the regenerative operation process is started.

In the regenerative operation process, the controller 18 first takes in the accelerator command output from the accelerator switch and stores the depression amount of the accelerator pedal 5 (step ST1). Further, the braking force range signal output from the regenerative braking force range switching lever 6 is taken in and the current lever position (range position) is stored (step ST2). Further, after the rotation detection signal output from the rotation sensor 17 is fetched and the current vehicle speed S of the electric vehicle is calculated and stored (step ST3), a preset map is accessed based on these stored contents. Then, the regenerative braking force value T ^* corresponding to the engine brake corresponding to the current accelerator pedal return amount, the range position of the regenerative braking force range switching lever 6 and the vehicle speed S is obtained (step ST4).

In parallel with this operation, the controller 18 takes in the voltage detection signal output from the voltage sensor 15, stores the current battery voltage value V, and detects the current output from the current sensor 16. The signal is taken in and the current value I input / output to / from the battery 7 is stored at present (step ST5). Then, after calculating the discharge depth DOD of the battery 7 based on the present battery voltage value V and the battery input / output current value I (step ST6), a preset map is accessed based on this discharge depth DOD. Then, the maximum regenerative power value P _max ^* corresponding to the current battery discharge depth DOD is obtained (step ST7).

Thereafter, the controller 18 causes the regenerative braking force value T ^* obtained by the above-described regenerative braking force value calculation process and the maximum regenerative power value P obtained by the maximum regenerative power value calculation process.
By accessing a preset three-dimensional map based on _max ^* and the vehicle speed S obtained based on the rotation detection signal output from the rotation sensor 17, positive and negative output torque values for the first motor 9, that is, Obtain the output torque value T ₁ for the power running operation or the regenerative operation (step ST
8).

Next, the controller 18 operates the exciting circuit in the first inverter 19 based on the output torque value T ₁ for the first motor 9 to excite the first motor 9 with high efficiency and to drive the first motor 9. as the output torque to the output torque value T _1, the first motor 9 or is power running driving, it causes regenerative drive (step ST9), a by subtracting the output torque value T ₁ from the output torque value T ' for 2 motor 10 obtains an output torque value T ₂ (step ST10), the second on the basis of the output torque value T ₂
The second motor 1 is operated by operating the exciting circuit in the inverter 20.
The second motor 10 is power-driven or regeneratively driven so that the output torque of the second motor 10 becomes the output torque value T ₂ while exciting 0 with high efficiency (step ST1).
1).

As a result, the depth of discharge of the battery 7 is large, and the maximum regenerative power P _max for the battery 7 is large.
^{When *} is large, the first motor 19 and the second motor 10 are driven by the first inverter 19 and the second inverter 20.
Preparative to regenerative operation, and the battery 7 can be charged by the regenerative electric power obtained by the regenerative operation, also the depth of discharge of the battery 7 is small, when the maximum regenerative power P _{ma x} ^* for the battery 7 is small, the Either the first motor 9 or the second motor 10 is regeneratively operated with high efficiency by the first inverter 19 or the second inverter 20, and the regenerative electric power obtained by this regenerative operation is supplied to the first motor 9 or the second motor 10. The remaining one can be consumed.

As described above, in this embodiment, when the accelerator pedal 5 is depressed, the first and second alternating currents are generated based on the direct current voltage of the battery 7 according to the amount of depression.
A driving current is generated to drive the first and second motors 9 and 10 to power the electric vehicle. After that, when the accelerator pedal 5 is returned, the depth of discharge of the battery 7 is detected and the battery 7 can be charged. In such a case, the first motor 9 and the second motor 10 are regeneratively operated, and the battery 7 is charged with the regenerative electric power obtained by this regenerative operation. If the battery 7 cannot be charged, , Either the first motor 9 or the second motor 10 is regeneratively operated, and the regenerative electric power obtained by this regenerative operation causes the remaining one of the first motor 9 or the second motor 10 to perform a powering operation to the battery 7. Since the regenerative braking is applied without charging, when the accelerator is turned off, the regenerative braking force according to the returning amount, stroke, etc. can be secured. In addition, the regenerative power can be controlled to be less than the maximum regenerative power of the battery 7 at that time, so that even when the battery 7 is near full charge, a constant braking force is always secured without regenerative resistance. can do.

FIG. 3 is a block diagram showing another embodiment of the power control device for an electric vehicle according to the present invention. In this figure, the same parts as those in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted. Further, for simplification of description, the output torque and heat capacity of the first motor 9 are set to values larger than the output torque and heat capacity of the second motor 10.

Power control device 1 for electric vehicle shown in this figure
Is based on the depression amount of the accelerator pedal 5 and the depression amount of the brake pedal 2 and the range position of the regenerative braking force range switching lever 6 so as to highly efficiently excite or efficiently drive the first and second motors 9 and 10 coaxially connected to each other. In addition to performing a power running operation or regenerative braking with deteriorated excitation, each brake mechanism 3 is operated according to the amount of depression of the brake pedal 2 to brake each tire 12 connected by the differential gear mechanism 11 to drive an electric vehicle. Decelerate and stop.

The control device 8 is provided with a pedal depression force sensor 21 which takes in a brake command output from the brake pedal 2 and generates a brake depression amount signal. The brake depression amount signal output from the pedal depression force sensor 21 is provided. Is an accelerator command from the accelerator switch, an accelerator off signal output from the accelerator off sensor 14, a voltage detection signal output from the voltage sensor 15, a current detection signal output from the current sensor 16, and an output from the rotation sensor 17. The rotation detection signal is supplied to the controller 18. Then, the controller 18 generates the first and second power running operation commands and the first and second regenerative operation commands.

Further, the controller 8 is a controller 1
When the first power running operation command is output from the first motor 8, the battery voltage (DC voltage) output from the battery 7 is taken in to generate an AC drive voltage having a specified excitation current and torque current ratio to generate the first motor. 9, when the first running operation command is output from the controller 18,
A first inverter that regeneratively operates the first motor 9 at a specified exciting current and torque current ratio to regeneratively brake the tire 12, and returns the regenerative power obtained by the regenerative operation to the battery 7 or the like to charge the regenerative power. 19, when the second power running operation command is output from the controller 18,
A battery voltage (DC voltage) output from the battery 7 is taken in to generate an AC drive voltage having a specified exciting current and torque current ratio to drive the second motor 10 for power running, and the controller 18 performs a second regeneration. When the operation command is output, the second motor 10 is supplied with a specified exciting current,
It is provided with a second inverter 20 that regeneratively operates at a torque current ratio to regeneratively brake the tire 12 and returns the regenerative power obtained by the regenerative operation to the battery 7 to charge it.

When the accelerator pedal 5 is stepped on, the control device 8 having the above-described structure generates the first and second alternating drive currents based on the direct current voltage of the battery 7 in accordance with the amount of stepping on the accelerator pedal 5. The second motors 9 and 10 are driven to power the electric vehicle, and thereafter, when the accelerator pedal 5 is returned or the brake pedal 2 is depressed, the depth of discharge of the battery 7 is detected and the battery 7 is charged. When possible, the first motor 9 and the second motor 10 are regeneratively operated, and the battery 7 is charged with the regenerative electric power obtained by this regenerative operation. When the battery 7 cannot be charged, either the first motor 9 or the second motor 10 is regeneratively operated by the high-efficiency excitation control method, and the first regenerative power obtained by the regenerative operation is used for the first operation. It is determined whether or not the remaining one of the motor 9 and the second motor 10 can be made to perform the power running by the high-efficiency excitation control method, and if this is possible, either the first motor 9 or the second motor 10 is set high. The regenerative operation is performed by the efficient excitation control method, and the first motor 9 or the second motor 9 is regenerated by the regenerative power obtained by the regenerative operation.
The other of the motors 10 is made to power-operate by the high-efficiency excitation control method. If this is not possible, the first motor 9 is regeneratively operated within a range where the first motor 9 is not unstable,
The second motor 1 uses the regenerative power obtained by this regenerative operation.
The second motor 10 is power-operated in the range where 0 does not become unstable. As a result, regenerative braking is applied without charging the battery 7.

Next, the regenerative driving operation of this embodiment will be described with reference to FIGS.

First, when the accelerator pedal 5 is returned and turned off from the state in which the accelerator pedal 5 is depressed, the controller 18 in the control device 8 operates on the basis of the output of the accelerator off sensor 14. Is detected and the regenerative operation process is started.

In the regenerative operation process, the controller 18 first takes in the accelerator command output from the accelerator switch and stores the depression amount of the accelerator pedal 5 (step ST15). Further, the braking force range signal output from the regenerative braking range switching lever 6 is taken in and the current lever position (range position) is stored (step ST16). Further, after taking in the rotation detection signal output from the rotation sensor 17 to calculate the current vehicle speed S and storing this (step ST17), a preset map is accessed based on these stored contents to access the present vehicle speed. The accelerator pedal return amount, the range position of the regenerative braking range switching lever 6, and the regenerative braking force value Te corresponding to the engine brake corresponding to the vehicle speed S are obtained (step ST
18).

In parallel with this operation, the controller 18 detects the brake depression amount F of the brake pedal 2 based on the output of the pedal depression force sensor 21 (step ST19), and based on this brake depression amount F, As shown in FIG. 7, a preset map is accessed to obtain the regenerative braking force value Tb for the brake depression amount F (step ST20), and these regenerative braking force values Te and Tb are added to perform full regeneration. A braking force (braking torque) T is obtained (step ST21), and further, the total regenerative braking force T, the rotation speed N indicating the vehicle speed S obtained by the rotation sensor 17, and a preset coefficient value "1. 026 ″ is multiplied to obtain energy (regenerative energy) P obtained by regenerative operation (step S
T22, ST23).

In parallel with this operation, the controller 18 takes in the voltage detection signal output from the voltage sensor 15, stores the current battery voltage value V, and detects the current output from the current sensor 16. After the signal is fetched and the current value I input / output to / from the battery 7 is stored (step ST24), the battery 7 is discharged based on the current battery voltage value V and the battery input / output current value I. After the depth DOD is calculated (step ST25), a preset map based on this discharge depth DOD is accessed to obtain the maximum regenerative power value P _max corresponding to the current battery discharge depth DOD (step ST26). .

After that, the controller 18 regenerates the regenerative energy P calculated by the regenerative braking force value calculation process and the maximum regenerative power value P calculated by the maximum regenerative power value calculation process.
Compare with _max, and if “P ≦ P _max ” (step S
T27), regenerative energy P obtained by regenerative operation
5 can be returned to the battery 7,
As shown in FIG. 5, the preset torque based on the vehicle speed S is accessed to output the output torque T ₁ of the first motor 9 with respect to the vehicle speed S, that is, the output of the first motor 9 capable of obtaining regenerative energy most efficiently. together determine the torque T ₁ (step ST28), the calculated output torque T ₂ of the second motor 10 from the total regenerative braking force T by subtracting the output torque T ₁ of the first motor 9 (step ST2
9), based on these output torque values T ₁ and T ₂ , operate the exciting circuits in the first and second inverters 19 and 20 to control the first and second motors 9 and 10 with high efficiency excitation vector. these first while, so that the output torque values T _1, T ₂ and the output torque of the second motor 9 and 10, first, second
The motors 9 and 10 are regeneratively operated, and the battery 7 is charged with the regenerative power obtained by this regenerative operation (step ST30).

As a result, the depth of discharge of the battery 7 is large, and the maximum regenerative power value P for this battery 7 is
_{When max} is large, the first motor 19 and the second motor 1 are _driven by the first inverter 19 and the second inverter 20.
The battery 7 can be charged with 0 and 0 for regenerative operation, and the regenerative electric power obtained by this regenerative operation.

In the process of comparing the regenerative energy P with the maximum regenerative power value P _max , "P≤
If it is not “P _max ” (step ST27), the controller 18 determines that all of the regenerative energy P obtained by the regenerative operation cannot be returned to the battery 7, and based on this determination result, the regenerative energy P is changed to the maximum regenerative energy. Electric power P _LOSS that must be consumed by the first motor 9 and the second motor 10 after subtracting the electric power value P _max
Is calculated (step ST31).

Next, the controller 18 sets "1≤k≤.
After setting the value of the variable k set in the range of “m” to “k = 1” (step ST32), from the minimum value T _1min of the output torque to the first motor 9 (the maximum value of the regenerative torque) to the first motor 9 A value in the range of the maximum value T _1max (maximum value of the power running torque) for the first motor 9 for the variable k (temporary output torque) T _1k (step ST33), and The temporary output torque T _1k of the first motor 9 is subtracted from the total regenerative braking force T to obtain a temporary output torque (temporary output torque) T _{2k of} the second motor 10.
Is calculated (step ST34).

After that, the controller 18 controls the first motor 9
When the first motor 9 is vector-controlled by high-efficiency excitation with the temporary output torque T _{1k of} , the energy consumed as heat by the first motor 9 (temporary loss value P _1k ) is obtained, and the second motor 10 When the second motor 10 is vector-controlled by high-efficiency excitation with the temporary output torque T _2k ,
Energy (temporary loss value P _2k ) consumed as heat in the motor 10 is calculated (step ST35), and the temporary loss value P _1k of the first motor 9 and the temporary loss value P _2k of the second motor 10 are added. The first motor 9 and the second motor 10 whose values are described above
It is determined whether or not it matches the power amount P _LOSS that must be consumed (step ST36).

If they do not match, the controller 18 continues until the variable k exceeds the maximum value m.
While incrementing the value of the variable k, the above-described setting process of the temporary output torque T _1k of the first motor 9, calculation process of the temporary loss value P _1k for this temporary output torque T _1k, and temporary output of the second motor 10 are performed. The setting process of the torque T _2k and the calculation process of the temporary loss value P _2k for the temporary output torque T _2k are repeated to obtain the temporary loss value P of the first motor 9.
It is determined whether or not the value obtained by adding _1k and the temporary loss value P _{2k of} the second motor 10 matches the amount of electric power P _LOSS that must be consumed by the first motor 9 and the second motor 10 described above ( Steps ST33 to ST38).

Then, the temporary loss value P _1k of the first motor 9 and
If the value obtained by adding the temporary loss value P _{2k of} the second motor 10 matches the electric energy P _LOSS that must be consumed by the first motor 9 and the second motor 10 described above (step ST
36), the controller 18 sets the temporary output torque T _1k of the first motor 9 as the actual output torque value T ₁ for the first motor 9, and the temporary output torque T _1k of the second motor 10
After the actual output torque value T ₂ the _2k (step ST3
8), based on the output torque value T ₁ for the first motor 9, the excitation circuit in the first inverter 19 is operated to vector-control the first motor 9 with high-efficiency excitation, and the output torque of the first motor 9 is So that the output torque value T ₁ becomes the output torque value T ₁ , the first motor 9 is regeneratively operated or the power running operation is performed, and the excitation circuit in the second inverter 20 is operated based on the output torque value T ₂ to the second motor 10. the second motor 10 is vector control highly efficiently excited, so that the output torque of the second motor 10 to the output torque value T _2, or the second motor 10 is a regenerative operation, thereby power operation Te (step ST40 ).

As a result, the depth of discharge of the battery 7 is small, and the maximum regenerative power value P for this battery 7 is P.
_{When max} is small, the first motor 9 or the second motor 10 is driven by the first inverter 19 or the second inverter 20.
Either one of them can be regeneratively operated with high efficiency, and the regenerative electric power obtained by this regenerative operation can be consumed by the remaining one of the first motor 9 and the second motor 10.

Further, in the above-mentioned processing, the value obtained by adding the temporary loss value P _1k of the first motor 9 and the temporary loss value P _2k of the second motor 10 is the above-mentioned first motor 9 or the second motor 10.
If it does not match the electric energy P _LOSS that has to be consumed by (steps ST36 and ST37), the controller 18 performs vector control of the first motor 9 and the second motor 10 with high-efficiency excitation, and the required total regenerative braking When it is determined that the amount of electric power P _LOSS required to obtain the power T cannot be secured, the efficiency of the first motor 9 and the second motor 10 is deteriorated and control is performed.

In this process, as shown in FIG. 6, the controller 18 first sets the output torque T ₁ of the first motor 9 to a value that maximizes the regenerative torque of the first motor 9, that is, the minimum output to the first motor 9. The torque T _1min is set as the output torque T ₁ of the first motor 9, and the loss value when the first motor 9 is vector-controlled by high-efficiency excitation to set the output torque T _1min is set as the minimum loss value P _1min (step ST4).
1).

After this, the controller 18 subtracts the output torque T _1min of the first motor 9 from the total regenerative braking force T to obtain the second torque.
The output torque (power running torque) T ₂ of the motor 10 is obtained, and the loss value when the second motor 10 is vector-controlled by high-efficiency excitation to obtain the output torque T ₂ is the minimum loss value P 2.
_{It is set to 2 minutes} (step ST42).

Next, when the controller 18 accesses a preset map to cause the first motor 9 to generate the regenerative torque of the output torque T ₁ , the efficiency is most deteriorated within the stable range. The loss value is calculated, and this value is set to P _1max, and the maximum loss value when the second motor 10 is made to output the power running torque at the output torque T ₂ is calculated, and this value is set to P _2max (step ST4).
3).

Next, the controller 18 causes the first motor 9
The regenerative torque of the second motor 10 has a larger absolute value than the power running torque of the second motor 10, and even if the efficiency is the same, the first motor 9 has a larger loss and produces a large amount of heat. In order to deteriorate the efficiency of the motor 10 earlier than that of the first motor 9, first, the value of the variable j set in the range of “1 ≦ j ≦ j _max ” is set to “j = 1” (step ST44). ), A value within a range from the minimum loss value P _1min for the first motor 9 to the maximum loss value P _1max for the first motor 9 is a temporary loss value for the first motor 9 for the variable j (provisional with the loss value) P _1j (step ST45), "1 ≦ i ≦ i ma x" value of the variable i is set in the range of "i = 1" and then after (step ST46), the second motor 10 Minimum loss value P for
Maximum value of loss P _2max for the second motor 10 from 2 _min
The value within the range up to the second motor 10 for the variable i
To the temporary loss value (temporary loss value) P _2i (step ST47), and the temporary loss value P _1j of the first motor 9
It is determined whether or not the value obtained by adding the temporary loss value P _{2i of} the second motor 10 matches the amount of electric power P _LOSS that must be consumed by the first motor 9 or the second motor 10 described above (step ST48). .

If these values do not match, the controller 18 increments the value of the variable i until the variable i exceeds the maximum value i _max, and the temporary loss value of the second motor 10 described above. The setting process of P _2i is repeated, and the value obtained by adding the temporary loss value P _1j of the first motor 9 and the temporary loss value P _{2i of} the second motor 10 is consumed by the first motor 9 and the second motor 10 described above. It is determined whether or not it matches the power amount P _LOSS to be made (steps ST45 to ST50).

If the variable i exceeds the maximum value i _max (step ST49), the controller 18 increments the value of the variable j and resets the temporary loss value P _1j of the first motor 9 (step ST51). , ST52), the setting process of the temporary loss value P _2i of the second motor 10 described above is repeated while incrementing the value of the variable i until the variable i exceeds the maximum value i _max. It is determined whether a value obtained by adding the loss value P _1j and the temporary loss value P _{2i of} the second motor 10 matches the amount of electric power P _LOSS that must be consumed by the first motor 9 or the second motor 10 described above. Judgment (steps ST47 to ST5
0).

Thereafter, the controller 18 repeats the setting process of the temporary loss value P _1j of the first motor 9 and the setting process of the temporary loss value P _2i of the second motor 10 until the variable j exceeds the maximum value j _max. The value obtained by adding the temporary loss value P _1j of the first motor 9 and the temporary loss value P _{2i of} the second motor 10 is the amount of electric power P _LOSS that must be consumed by the first motor 9 and the second motor 10 described above. It is determined whether they match (steps ST45 to ST52).

Then, the temporary loss value P _1j of the first motor 9
If the value obtained by adding the temporary loss value P _{2i of} the second motor 10 matches the electric energy P _LOSS that must be consumed by the first motor 9 and the second motor 10 described above (step ST
48), the controller 18 sets the temporary loss value P _1j for the first motor 9 as the actual loss value P ₁ and sets the temporary loss value P _2i for the second motor 10 as the actual loss value P ₂ and then sets in advance. The ratio of the exciting current and the torque current required to realize the loss value P ₁ for the first motor 9 is obtained by accessing the stored map and the second motor 10
Excitation current required to realize the loss value P ₂ for
The ratio of torque currents is obtained (step ST53).

Further, even if the variable j exceeds the maximum value j _max and the variable i exceeds the maximum value i _max , the temporary loss value P _1j of the first motor 9 and the temporary loss value P _2i of the second motor 10 are also. If the value obtained by adding and does not match the electric energy P _LOSS that must be consumed by the first motor 9 and the second motor 10 described above, the controller 18 determines that the temporary loss value P of the first motor 9 is P.
Of the value obtained by adding _1j and the temporary loss value P _{2i of} the second motor 10, the first value that is the value closest to the electric energy P _LOSS that must be consumed by the first motor 9 or the second motor 10 described above. The temporary loss value P _1j of the motor 9 and the temporary loss value P _2i of the second motor 10 are selected (steps ST49, ST5).
1).

Then, the controller 18 uses the first motor 9
_{Is set} to the actual loss value P ₁ and the temporary loss value P _2i to the second motor 10 is set to the actual loss value P _2, and then a preset map is accessed to access the first loss value P _1j . The ratio between the exciting current required to realize the loss value P ₁ for the motor 9 and the torque current is obtained, and the ratio between the exciting current required to achieve the loss value P ₂ for the second motor 10 and the torque current is obtained. (Step ST5
3).

After that, the controller 18 controls the first motor 9
The first inverter 19 is controlled on the basis of the ratio of the exciting current to the torque current, the first motor 9 is vector-controlled by the first inverter 19 to perform the regenerative operation, and the exciting current to the second motor 10 and the torque are controlled. The second inverter 20 is controlled based on the current ratio, and the second motor 20 is vector-controlled by the second inverter 20 to perform a power running operation (step ST54).

As a result, the depth of discharge of the battery 7 is small, and the maximum regenerative power value P for this battery 7 is P.
_{Even if max} is small and the first inverter 19 and the second inverter 20 are excited with high efficiency, the required electric power P _LOSS
Even when it is not possible to secure the
In the range in which the first motor 9 is not unstable due to 9, the efficiency of the first motor 9 is deteriorated to perform the regenerative operation, and the second motor 10 is in the range in which the second inverter 20 does not become unstable. It is possible to secure the required amount of electric power P _LOSS by operating the vehicle.

As described above, in this embodiment, when the accelerator pedal 5 is returned or the brake pedal 2 is depressed, the depth of discharge of the battery 7 is detected, and when the battery 7 can be charged, The first motor 9 and the second motor 10 are regeneratively operated, and the battery 7 is charged with the regenerative electric power obtained by this regenerative operation. If the battery 7 cannot be charged, the first motor 9 or One of the second motors 10 is regeneratively operated by the high-efficiency excitation control method, and the remaining power of the first motor 9 or the second motor 10 is regenerated by the regenerative operation by the high-efficiency excitation control method. It is determined whether the power running operation can be performed, and if this is possible, either the first motor 9 or the second motor 10 is regeneratively operated by the high-efficiency excitation control method, and the regenerative operation is performed. The regenerative power obtained by rolling 1
The other of the motor 9 and the second motor 10 is made to perform a power running operation by a high-efficiency excitation control method.
The first motor 9 is regeneratively operated within a range where the motor 9 is not unstable, and the second motor 10 is power-operated within a range where the second motor 10 is not unstable by the regenerative electric power obtained by the regenerative operation. Therefore, the regenerative braking force according to the pedaling force and the stroke when the accelerator is turned off or the brake pedal 2 is depressed can be secured, and the battery 7 at that time can be secured.
It is possible to control the regenerative power below the maximum regenerative power of
As a result, even when the battery 7 is near full charge, a constant braking force can be always secured without regenerative resistance.

Further, in this embodiment, even when the brake pedal 2 is depressed, at least one of the first and second motors 9 and 10 is regeneratively operated, so that the battery 7 is sufficiently charged. If it is in a state where it can return a large amount of electric power, more electric power can be regenerated and returned to the battery 7 than the device of the embodiment shown in FIG.

In this embodiment, one of the first and second motors 9 and 10 performs regenerative operation so that regenerative braking force can be obtained as a whole, and the remaining one performs power running operation. Therefore, the regenerative torque must be larger than the power running torque. As a result, a motor having a larger torque and a large heat capacity must be used as a motor for regenerative operation. Therefore, the first motor 9 is determined for regeneration and the second motor 10 is determined for power running. When using motors having the same torque and heat capacity as the first and second motors 9 and 10, temperature sensors are provided to the first and second motors 9 and 10, and the motor having the lower temperature is used by each of these temperature sensors. The regenerative operation may be performed and the motor having a high temperature may be operated in the power running operation.

[0065]

As described above, according to the present invention, it is possible to secure the regenerative braking force according to the pedaling force, stroke, etc. when the accelerator is turned off or the brake pedal is stepped on. The regenerative electric power can be controlled to be equal to or less than the maximum regenerative electric power of the battery at the time point, and thus, even when the battery is near full charge, a constant braking force can be always secured without regenerative resistance.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a power control device for an electric vehicle according to the present invention.

FIG. 2 is a flowchart showing an operation example of the electric vehicle power control device shown in FIG.

FIG. 3 is a block diagram showing another embodiment of the power control device for an electric vehicle according to the present invention.

FIG. 4 is a flowchart showing an operation example of the electric vehicle power control device shown in FIG. 3.

5 is a flowchart showing an operation example of the power control device for the electric vehicle shown in FIG.

6 is a flowchart showing an operation example of the power control device for the electric vehicle shown in FIG.

7 is an explanatory diagram showing an example of braking characteristics of the power control device for an electric vehicle shown in FIG.

FIG. 8 is a block diagram showing an example of a conventionally known power control device for an electric vehicle.

FIG. 9 is an explanatory diagram showing an example of efficiency-torque command current / drive command current characteristics of a motor obtained by an experiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Power control device for electric vehicle 2 Brake pedal 3 Brake mechanism 5 Accelerator pedal 6 Regenerative braking range switching lever 7 Battery 8 Control device 9 1st motor 10 2nd motor 11 Differential gear mechanism 12 Tire 13 Wheel axle 14 Accelerator off sensor 15 Voltage Sensor 16 Current sensor 17 Rotation sensor 18 Controller (Chargeability determination unit, Full regeneration operation unit,
Semi-regenerative operation part) 19 1st inverter 20 2nd inverter 21 Pedal pedal force sensor

Claims (1)

[Claims] 1. A power control device for an electric vehicle that individually performs a power running operation and a regenerative operation of a plurality of motors mounted on an electric vehicle, each of which is operated when an accelerator pedal is returned or a brake pedal is depressed. A chargeability determination unit that determines whether regenerative power obtained by regenerative operation of the motor can be returned to the battery, and all regenerative power obtained by regenerative operation of each motor by this chargeability determination unit is returned to the battery. When it is determined that each motor is regeneratively operated, the regenerative operation of each motor is performed, and the regenerative power obtained by this regenerative operation is returned to the battery. When it is determined that all the regenerative power obtained from the above cannot be returned to the battery, it is said that a part of each motor is regenerated. In addition, a power control for an electric vehicle comprising: a semi-regenerative operation unit that causes the remaining motor to consume at least a portion of the regenerative power obtained by this regenerative operation that cannot charge the battery. apparatus.