JPH06153310A - Brake system for electric automobile - Google Patents

Abstract

PURPOSE:To provide a brake system for electric automobile which can achieve a target deceleration without lowering deceleration. CONSTITUTION:The brake system calculates a target regenerative power of a regenerative brake such that the sum of hydraulic brake regenerative brake power corresponds to a target deceleration of an electric automobile and a target regenerative power is returned to superconducting coils 19, 20. A power consuming section 16 is arranged in parallel with the superconducting coils 19, 20 in order to consume excess regenerative power through resistors.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a braking device for an electric vehicle, and more particularly to a braking device for an electric vehicle that performs braking using a hydraulic brake and a regenerative brake.

[0002]

2. Description of the Related Art Conventionally, there is a DC electric vehicle that regenerates electric power by using a superconducting coil, as described in Japanese Patent Application Laid-Open No. 1-185101.

[0003]

SUMMARY OF THE INVENTION In an electric vehicle, a normal hydraulic brake and a regenerative brake using a superconducting coil are used together so that a target deceleration can be obtained by the sum of the hydraulic braking force and the regenerative braking force. Is controlled, the amount of electric power to be regenerated at the start of braking is determined. However, since the superconducting coil has a large inductance, regeneration cannot be performed immediately at the start of braking. Therefore, there is a problem that the deceleration at the start of braking is reduced.

The present invention has been made in view of the above points,
An object of the present invention is to provide a braking device for an electric vehicle that can obtain a target deceleration without lowering the deceleration by consuming resistance that cannot be regenerated when the target regenerative power cannot be regenerated by a superconducting coil.

[0005]

The braking device for an electric vehicle according to the present invention calculates the target regenerative electric power of the regenerative brake so that the sum of the braking forces of the hydraulic brake and the regenerative brake is the target deceleration of the electric vehicle. A braking device for an electric vehicle that regenerates the target regenerative power to a superconducting coil, and the braking device is provided in parallel with the superconducting coil, and when the target regenerative power cannot be regenerated to the superconducting coil, the non-regenerative power is consumed by a resistor. It has a power consumption unit.

[0006]

In the present invention, when the target regenerative electric power exceeds the electric power that can be received by the superconducting coil, the electric power that cannot be regenerated is consumed by the resistance, so that the deceleration of the regenerative brake due to the electric power that cannot be regenerated is prevented from decreasing. It

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a circuit diagram of an embodiment of the device of the present invention. In the figure, the motor 10 is connected to a DC power supply 12 of a voltage V _B via an inverter unit 11, and the DC power supply 1
Powered by 2 to rotate and drive the car.

The smoothing section 15 is connected to the inverter section 11 via the current control section 14, and the smoothing section 15 is connected to the power consumption section 1.
6 and bridge portions 17 and 18 are connected in parallel.
The bridge portions 17 and 18 have the same structure, and superconducting coils 19 and 20 are connected to the bridge portions 17 and 18, respectively.

The bridge circuits 17 and 18 are composed of a thyristor T.
By turning on both h1 and Th2, the superconducting coil 1
9 is charged, the power of the superconducting coil 19 is held by turning on one of the thyristors Th1 and Th2 and turning off the other, and the superconducting coil 19 is discharged by turning off both of the thyristors Th1 and Th2. .

The thyristor Th4 and the resistor R3 provided in parallel with the superconducting coils 19 and 20 turn on the thyristor Th4 and turn on the resistor R3 when the normal conducting transition occurs in the superconducting coils 19 and 20 due to a mechanical shock or the like. It is provided to protect the superconducting coils 19 and 20 by the power consumption of.

The voltage of the power source 12 is detected by the voltmeter 21 and supplied to the control unit 22, and the current values flowing through the superconducting coils 19 and 20 detected by the ammeters 23 and 24 are also supplied to the control unit 22. Has been done. The control unit 22 controls on / off of the switch SW1 of the current control unit 14 and the base current of the transistor Tr1, and at the same time, the power consumption unit 1
6 controls the on / off of the thyristor Th3, and controls the on / off of each of the thyristors Th1 and Th2 of the bridge units 17 and 18.

FIG. 2 shows a flowchart of the regenerative control process executed by the control unit 22. This process is executed when braking is started.

In the figure, in step S2, the brake pedal force F
Enter. Next, in step S4, this brake pedal force F is compared with a predetermined value f _A. The predetermined value f _A is the pedaling force corresponding to the maximum braking force of the regenerative brake as shown in FIG. 3, and the brake pedaling force F up to the predetermined value f _A performs braking by the regenerative brake, and the brake pedaling force exceeding this is shown in FIG. As described above, braking is performed by the normal hydraulic brake.

When F> f _{A in} step S4, the maximum power Pmax is set to the received power Pref for regeneration in step S6, and when F ≦ f _A , the received power Pref in step S8
The electric power y (F) obtained from the function of the pedal effort F is set in ref.

Thereafter, in step S10, the voltage V measured by the voltmeter 21 and the coil current I ₀ measured by the ammeters 23 and 24 are input. Next, in step S12, it is determined whether the received power Pref exceeds the power I ₀ · V.

Here, the acceptable power W of the superconducting coil is the power supply voltage V, the inductance L of the superconducting coil,
It is expressed by the following equation using the current I ₀ flowing in the superconducting coil and the time t.

[0017]

[Number 1] (1) is as shown in FIG. 5, acceptable electric power W at time t = 0 in the V · I _0, then, represents that increases with time t.

If Pref> I ₀ .V in step S12, the superconducting coils 19 and 20 can instantly receive the received power Pref. Therefore, the process proceeds to step S14, the switch SW1 is turned on, and the bridge unit 1 is operated in step S16.
The duty ratio for turning on each of the thyristors Th1 and Th2 is calculated, for example, the thyristor Th1 is turned off, and the received power Pref is regenerated in the superconducting coils 19 and 20 by turning on Th2 at this duty ratio.
The process ends.

If Pref ≤ I ₀ · V in step S12, the received power Pref cannot be instantaneously received by the superconducting coils 19 and 20, so the switch SW1 is turned off in step S18, and the received power Pref is regenerated in step S20. After controlling the base current of the transistor Tr1 of the current control unit 14 so that a current value required for
The thyristors Th1 and Th of the bridge portions 17 and 18 at 22
2 is turned on and the thyristor Th3 of the power consumption unit 16 is turned on.
Is turned on to end the process.

In this case, the power received by the superconducting coils 19 and 20 when the thyristors Th1 and Th2 are turned on increases with time as shown by the solid line in FIG. 5, but the received power Pref is superconducting until time t ₁ as shown by the broken line. Coil 1
It exceeds the acceptable power of 9,20. However, when the thyristor Th3 of the power consumption unit 16 is turned on, the electric power that cannot be received by the superconducting coils 19 and 20 shown by the diagonal lines in FIG. 5 is consumed by flowing through the discharge resistor R2.

For example, when the combined inductance of the superconducting coils 19 and 20 is 10 H, the charging start current I ₀ is 10 A, and the power supply voltage V is 300 V, the received power Pref is 15 k.
When receiving the instruction to set w (= 300 V × 50 A), the transistor Tr1 is commanded to energize 50 A, and
The thyristors Th1, Th2 and Th3 are turned on. As a result, the current flowing into the superconducting coils 19 and 20 changes as shown by the solid line I in FIG. 6, the current consumed by the resistor R2 changes as shown by the solid line II, and the total becomes 50 A as shown by the broken line III.

By the way, when the superconducting coil 19 has an inductance of 10 H and a current of 100 A is flowing, the stored energy is 1/2 · 10 · (100) ²
= 50 KJ. From this state, for example, the voltage V _B = 30
In order to discharge 3 KW of electric power to the 0V DC power supply 12 side, it is necessary to set the resistance R1 = 0.1Ω and to supply an average current of 10 A to this resistance. In this case, for example, the thyristor Th1 is turned off and the thyristor Th2 is duty-controlled at the duty ratio 1 / D.

The above-mentioned D is determined by the following equation as a current I _O flowing through the superconducting coil 19 and a discharge current I _B.

[0024] _{D (t) ≒ I B /} I O Thus, thyristors without duty control Th
When both 1 and Th2 are turned off, the current flows as shown by the solid line I in FIG. 7 (A), while the solid line II in FIG. 7 (B) flows.
A current of about 10 A flows as shown in FIG. The same applies to the duty control during regeneration performed in step S16 of FIG. In this way, the target regenerative power is the superconducting coils 19, 2
When the electric power that can be accepted to 0 is exceeded, the electric power that cannot be regenerated is consumed by the resistor R2, so that the deceleration of the regenerative brake due to the electric power that cannot be regenerated is prevented from decreasing and the target deceleration can be obtained.

[0025]

As described above, according to the braking system for an electric vehicle of the present invention, when the target regenerative electric power cannot be regenerated by the superconducting coil, the electric power that cannot be regenerated is consumed by the resistance, and the target deceleration is reduced without a decrease in deceleration. It can be obtained and is extremely useful in practice.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram of an embodiment of a device of the present invention.

FIG. 2 is a flowchart of a regeneration control process.

FIG. 3 is a diagram showing a brake characteristic.

FIG. 4 is a diagram showing a brake characteristic.

FIG. 5 is a diagram for explaining the operation of the present invention.

FIG. 6 is a diagram for explaining the operation of the present invention.

FIG. 7 is a diagram for explaining duty control.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 motor 11 inverter part 12 DC power supply 14 current control part 15 smoothing part 16 power consumption part 17,18 bridge part 19,20 superconducting coil 22 control part

Claims (1)

[Claims] 1. A target regenerative power of the regenerative brake is calculated so that the sum of the braking forces of the hydraulic brake and the regenerative brake is the target deceleration of the electric vehicle, and the target regenerative power of the electric vehicle that regenerates the target regenerative power in a superconducting coil. A braking device for an electric vehicle, which is provided in parallel with the superconducting coil and has a power consuming unit that consumes the non-regenerative electric power with a resistor when the target regenerative electric power cannot be regenerated in the superconducting coil. apparatus.