JPH058728Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a drive device for an electric vehicle, and more particularly to a braking control device for an electric vehicle using a chopper control that performs dynamic braking.

[Conventional technology]

A conventional brake control device for an electric vehicle using chopper control is shown in FIG. Also, between the armature 1a and the field coil 1b, there is a forward rotation coil for changing the direction of the current flowing through the field coil 1b in order to rotate the armature 1a forward or reverse according to the forward or reverse movement of the electric vehicle. A contactor F and a reversing contactor R are connected, and a main circuit contactor M and a braking resistor RA are connected in parallel to the field coil 1b. In addition, the motor circuit (1a, 1b, F,
A flywheel diode 4 is connected in parallel to R, M, and RA). The DC power supply 3 is further connected to a microswitch 5 which is linked to the accelerator of an electric vehicle (not shown) via a key switch SW and a protection circuit contact 6, and this microswitch 5 connects two circuits in parallel, namely , a circuit between the forward switch FS and the forward rotation contactor excitation coil F1, and a circuit between the reverse rotation switch RS and the reverse rotation contactor excitation coil R1 are connected. Forward and reverse switches FS and RS, forward and reverse contactor excitation coils F1 and R1 constitute a forward and reverse control circuit 10. The micro switch 5 and the forward/reverse control circuit 10 constitute a brake control device. The chopper control circuit 7 controls the chopper circuit 2, receives signals indicating the activation of the forward and reverse switches FS and RS, and is connected to the circuit for energizing the main circuit contactor excitation coil M1.

When the key switch SW is turned on, power is supplied from the DC power supply 3 to various circuits (not shown) on the printed board 20. When the forward switch FS is turned on and the accelerator is pressed, the micro switch 5 is turned on, and the chopper control circuit 7 is activated, which closes the main circuit contactor M. The chopper circuit 2 is activated to supply a predetermined pulse voltage to the DC motors 1a and 1b. Then, the electric vehicle moves forward by rotating in the forward direction. When you release the accelerator in this state, the contactor F for forward rotation is "open" and at the same time, the main circuit contactor M is "open" due to the operation of the chopper control circuit 7, and the contactor R for reverse rotation is "closed", so the DC motor starts generating electricity. The generated current flows through the braking resistor RA, consuming rotational energy and applying braking. However, since the field coil 1b is switched for this braking, the direction of the current is reversed and the effect of the residual magnetic flux cannot be used. Therefore, the chopper circuit 2 is operated to apply a voltage with the minimum pulse width to the DC motors 1a and 1b. It is necessary to supply this power and perform dynamic braking. Therefore, since the chopper circuit 2 is operated even during braking, chopper noise not only occurs and causes discomfort, but also the chopper control circuit 7 which also controls the excitation coil of the reverse or forward contactor for starting braking. The disadvantage is that the structure is complicated.

[Problem that the invention attempts to solve]

An object of the present invention is to provide a brake control device for an electric vehicle that can perform dynamic braking with a simple circuit without operating a chopper circuit.

[Means for solving problems]

The braking control device for an electric vehicle of the present invention has an accelerator-linked microswitch, an excitation connection line for braking, and a forward/reverse control circuit, and the forward/reverse control circuit includes a contactor excitation coil for forward rotation and a contactor excitation coil for reverse rotation. and a main circuit contactor excitation coil, and when braking when the accelerator is released, the main circuit contactor excitation coil operates, and the forward rotation contactor excitation coil or reverse rotation contactor excitation coil is activated by the forward rotation switch or reverse rotation switch. is selected, and the accelerator-linked micro switch is
It has a fixed contact for forward/reverse travel and a fixed contact for braking, the fixed contact for forward/reverse is connected to a forward/reverse control circuit, the fixed contact for braking is connected to the forward/reverse control circuit via a braking excitation connection line, By releasing the accelerator while the electric vehicle is moving forward or backward, the movable contact contacts the fixed contact for braking and excites the contactor excitation coil for reverse rotation or the contactor excitation coil for forward rotation. The contactor is "closed" and the contactor for forward rotation is kept "closed", and when braking while moving in reverse, the contactor for forward rotation is "closed" and the contactor R for reverse rotation is kept "open", generating electricity in the armature of the DC motor. Electrical braking is performed by passing current through the braking resistor.

[Effect]

In a DC motor, current flows from the chopper circuit through the field coil, forward rotation and reverse rotation contactors, and opening and closing of these contactors reverses the direction of the armature current, but the direction of the current flowing through the field coil does not change. do not. When you release the accelerator while the electric vehicle is moving forward or backward, the excitation of the forward or reverse contactor is cut off and its contacts open, and the excitation of the main circuit contactor is also cut off and its contacts opened, and at the same time, the accelerator-linked micro The movable contact of the switch contacts a fixed contact different from the fixed contact for forward/reverse braking, and current flows through the braking excitation connection line to energize the reverse rotation contactor or the forward rotation contactor and close the contact. Since the armature is rotating, the residual magnetic flux of the field coil acts as a generator, and the generated current flows to the braking resistor, consuming rotational energy.

〔Example〕

An embodiment of the present invention will be described with reference to the circuit diagram of FIG. The circuit of the present invention is different from the conventional circuit shown in FIG. The current flowing through the armature 1a is reversed by opening and closing the reversing contactor R, and the reversing contactor excitation coil is connected to the braking fixed contact 5b, which is different from the forward/reverse fixed contact 5a of the micro switch 5 linked to the accelerator. Braking excitation connection wire 8 connected to R1 (or forward rotation contactor excitation coil F1)
has been established. Further, the main circuit contactor excitation coil M1 is connected to a signal line connected to the chopper control circuit 7 from the forward switch FS and the reverse switch RS. The forward and backward movement control circuit 10 includes a forward movement switch Fs and a forward movement contactor excitation coil F.
1, a series circuit of a reverse switch Rs and a reverse contactor excitation coil R1, and a main circuit contactor excitation coil M1, and these series circuits are mutually connected in parallel to an accelerator interlocking microswitch 5. . Therefore, the accelerator interlocking micro switch 5, the braking excitation connection line 8, and the forward/reverse control circuit 10 constitute a brake control device for an electric vehicle.

To explain the operation, when the key switch SW is turned on, power is supplied to various circuits on the printed board 20. Forward switch to move the electric car forward
When the FS is turned on and the accelerator is depressed, the micro switch 5 linked to it enters the forward/reverse fixed contact 5a, and current passes through the forward switch FS to excite the forward rotation contactor excitation coil F1 and also the main circuit contactor excitation coil M1. Excite. Therefore, the forward rotation contactor is "closed" (connected to contact Fa), and the main circuit contactor M is also "closed". The reversal contactor remains open (contact Rb). A signal indicating that the forward switch FS has been turned on is supplied to the chopper control circuit, which causes the chopper circuit 2 to operate and supply a predetermined voltage pulse to the DC motor 1, causing the armature 1a to rotate in the forward direction. In this state, when the accelerator is released, the micro switch 5 separates from the forward/reverse contact 5a and connects to the braking fixed contact 5b, so the current passes through the braking excitation connection wire 8 and excites the reversing contactor excitation coil R1. death,
The reverse contactor R becomes "closed" (contact Ra).
At the same time, no current flows from the forward switch FS to the forward contactor excitation coil F1 and the main circuit contactor excitation coil M1, so the forward contactor F becomes "open" (contact Fb) and the main circuit contactor M also becomes "open". Further, the chopper circuit 2 stops operating. Since the armature 1a is still rotating, power is generated by the residual magnetic flux of the field coil 1b, and the generated current flows through the braking resistor RA and consumes rotational energy to perform dynamic braking.

Furthermore, if the braking excitation connection line 8 is connected from the braking fixed contact 5b of the micro switch 5 to the forward rotation contactor excitation coil F1, dynamic braking is performed when the electric vehicle moves backward.

[Effect of idea]

The field coil of the DC motor is connected to a chopper circuit, and the forward and reverse contactors connected between the field coil and the armature open and close when braking from forward or reverse, and determine the direction of the current flowing to the armature. Since the direction of the current flowing through the field coil does not change even during braking, the residual magnetic flux of the field coil can be used, and there is no need to operate a chopper circuit as in the conventional case. Therefore, generation of noise from the chopper circuit during braking can be prevented. In addition, we provided a braking excitation connection line that is directly connected to the reverse contactor excitation coil or the forward rotation contactor excitation coil from the braking fixed contact, which is different from the forward/reverse fixed contact of the micro switch linked to the accelerator. When the electric vehicle moves forward or backward, when the accelerator is released, the reversal contactor closes the forward rotation contactor through this braking excitation line, and the polarity of the armature can be switched to dynamic braking. Therefore, the operation of the chopper control circuit eliminates the need to excite the reverse contactor excitation coil or the forward rotation contactor excitation coil, simplifying the circuit.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an embodiment of the brake control device for electric vehicles of the present invention, and FIG. 2 is a circuit diagram of a conventional device. In the figure, 1... DC motor, 1a... Armature, 1b... Field coil, 2... Chopper circuit,
3... DC power supply, 5... Accelerator interlocking micro switch, 5a... Fixed contact for forward and backward movement, 5b... Excitation connection line for braking, 7... Chopper control circuit, 8...
...Braking excitation connection line, 10... Forward/forward control circuit,
F...Forward rotation contactor (F1 excitation coil), R
...Reverse contactor (R1 excitation coil), FS...
...Forward switch, RS...Reverse switch, M
...Main circuit contactor (M1 excitation coil), RA
...braking resistance, SW...key switch.

Claims (1)

[Scope of Claim for Utility Model Registration] A brake control device for an electric vehicle having an accelerator interlocking microswitch 5, a braking excitation connection line 8, and a forward/reverse control circuit 10, which includes: Traveling is controlled by the chopper circuit 2 and the DC motor 1, which are controlled by the above, and the forward and reverse directions are switched by the forward rotation contactor F or the reverse rotation contactor R.
A main circuit contactor M and a braking resistor RA connected in parallel to it are connected, and the forward/reverse control circuit 10 includes a forward rotation contactor excitation coil F1, a reverse rotation contactor excitation coil R1, and a main circuit contactor excitation coil M1. When braking after releasing the accelerator, the main circuit contactor excitation coil M1 is activated, and the forward rotation contactor excitation coil F1 or the reverse rotation contactor excitation coil R1 is activated by the forward rotation switch Fs or the reverse rotation switch Rs.
is selected, and the accelerator quick-acting micro switch 5 has a forward/reverse fixed contact 5a and a braking fixed contact 5b, the forward/reverse fixed contact 5a is connected to the forward/reverse control circuit 10, and the braking fixed contact 5b is the braking excitation connection wire 8
When the electric vehicle is moving forward or backward, the movable contact contacts the fixed contact 5b for braking, and excite the reverse contactor excitation coil R1 or the forward rotation contactor. The coil F1 is energized, so that when braking while moving forward, the reverse rotation contactor R is "closed" and the forward rotation contactor F is kept "closed", and when braking during reverse movement, the forward rotation contactor F1 is kept "closed". , the reversing contactor R is kept open and the current generated in the armature 1a of the DC motor 1 is passed through the braking resistor RA to perform dynamic braking. Brake control device for electric vehicles.