JPH062902U - Electric vehicle control circuit - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a control circuit for an electric vehicle capable of performing excellent regenerative braking. [Configuration] Field windings 4b, 5 of two DC motors 4, 5
b is connected in parallel, and diodes 20, 21, 16 and 17 for regenerative braking are provided so that regenerative current flows through both DC motors 4 and 5 even when there is a difference in the rotational speed of each DC motor 4 and 5. It is the one.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a control circuit for an electric vehicle, and is particularly useful when applied to an electric vehicle in which left and right wheels are driven by separate DC motors, such as a two-motor battery forklift.

[0002]

[Prior art]

 FIG. 2 is an explanatory view conceptually showing a two-motor battery forklift. As shown in the figure, this forklift truck is a three-wheel electric vehicle having left and right wheels 1 and 2 which are drive wheels and one steering wheel 3, and uses a battery (not shown) as a power source. Wheels 1 and 2 are rotated by individual DC electric motors 4 and 5, respectively, and traveling is performed by controlling current supplied to DC electric motors 4 and 5 by a chopper circuit (not shown) to control speed. I am doing it.

Further, when decelerating from the power running state of the forklift (the direction of the output torque of the DC motors 4, 5 and the direction of rotation of the wheels 1, 2 is the same), the braking torque is obtained by plugging. There is.

[0004]

[Problems to be solved by the device]

 When attempting to generate a sufficient braking torque by plaque braking as described above, there is a problem that the currents of the armatures 4a, 5a of the DC motors 4, 5 become excessive and the brush life of the DC motors 4, 5 becomes short. is there.

On the other hand, similarly to the one-motor battery forklift that obtains the driving force by one DC motor, a regenerative braking circuit is added to the control circuit of the above-mentioned two-motor battery forklift to obtain the braking force by the regenerative braking. It is also possible.

FIG. 3 is a circuit diagram showing a control circuit in which a circuit for regenerative braking is simply added to the control circuit of a conventional two-motor battery forklift truck. As shown in the figure, the DC motors 4 and 5 are series-wound motors having armatures 4a and 5a and field windings 4b and 5b, respectively. The electromagnetic switches 6, 7, 8, 9 each have two contacts 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b and one contact piece 6c, 7c, 8c, 9c. At the time of forward rotation of the DC motors 4 and 5 (forward movement of the forklift), the contacts 6a and 7b are selected by the contact pieces 6c and 7c, and the contacts 8a and 9b are selected by the contact pieces 8c and 9c. At the time of reverse rotation (retraction of the forklift), the contact points 6b, 7a, 8b, 9a are selected respectively by the contact pieces 6c, 7c, 8c, 9c. The electromagnetic openers 10 and 11 are switches that are normally closed and open during regenerative braking.

In FIG. 3, 12 is a battery, 13 is a chopper circuit for current control, and 14, 15, 16, 17, and 18 are diodes.

In the above control circuit, the regenerative braking state is set by opening the electromagnetic switches 10 and 11, and the closed circuit that passes through the armatures 4 a and 5 a, the diodes 14 and 15, the battery 12, and the diodes 16 and 17 is used. While the power is regenerated in the battery 12, a regenerative current flows due to a closed circuit passing through the armatures 4a and 5a, the field windings 4b and 5b, the chopper circuit 13 and the diodes 16 and 17, but one chopper circuit 13 When performing current control with, the DC motor 4 or 5 with a high rotation speed is in a regenerative state due to the difference in the rotation speed of the left and right DC motors 4 and 5, and the regenerative current does not flow to the one with a low rotation speed. No deceleration torque is generated. Therefore, when the forklift decelerates, the vehicle body swings to the left and right, which causes a problem.

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide a control circuit for an electric vehicle capable of performing good regenerative braking.

[0010]

[Means for Solving the Problems]

 The configuration of the present invention which achieves the above object is configured such that two DC motors drive left and right wheels respectively, and in a control circuit of an electric vehicle provided with a circuit for regenerative braking, each field of the DC motor is It is characterized in that the magnetic windings are connected in parallel, and that the field windings of the DC motor are connected in parallel to each other via a switch means that switches at the time of regenerative braking.

[0011]

[Action]

 According to the present invention having the above-mentioned configuration, since the field windings of the left and right DC motors are connected in parallel, the field currents become equal, and even if there is a difference in the number of rotations of both DC motors, the ratio of the number of rotations Corresponding to, a regenerative current flows through each DC motor.

[0012]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same parts as those in FIG. 3 are designated by the same reference numerals.

The present embodiment is a control circuit for a two-motor battery forklift truck shown in FIG. 2. As shown in FIG. 1, the field windings 4b, 5b of the DC motors 4, 5 are connected in parallel. A current sensor 15 is connected on the way from the armatures 4a and 5a to the field windings 4b and 5b, and regenerative braking is provided between the positive side of the battery 12 and both ends of the field windings 4b and 5b. Diodes 20 and 21 for use are connected to each other.

When the forklift having such a control circuit moves forward, it passes from the battery 12 through the electromagnetic switches 10 and 11 to the electromagnetic switches 6 and 8, the armatures 4 a and 5 a, the electromagnetic switches 7 and 9, the current sensor 19, and the field. By forming a closed circuit that returns to the battery 12 via the magnetic windings 4b and 5b and the chopper circuit 13, current is supplied to the DC motors 4 and 5, and the current value is controlled by the chopper 13 to control the traveling speed. To do.

On the other hand, during regenerative braking, the electromagnetic switches 10 and 11 are opened. As a result, a closed circuit passing through the armatures 4a and 5a, the current sensor 19, the diode 20, the battery 12 and the diodes 16 and 17, the armatures 4a and 5a, the current sensor 19, the field windings 4b and 5b, and the diode 21. , A closed circuit that passes through the battery 12 and the diodes 16 and 17 regenerates power to the battery 12, and at the same time, armatures 4a and 5a, current sensor 19, field windings 4b and 5b, chopper circuit 13, and diode 16, A closed circuit passing through 17 causes regenerative current to flow. As a result, the field currents flowing through the field windings 4b and 5b become equal, and even if there is a difference in the number of revolutions of the DC motors 4 and 5, the regenerative current corresponds to the ratio of the numbers of revolutions of the DC motors 4 and 5. 5, the forklift goes straight and good regenerative braking is performed.

Although the field windings 4b and 5b are always connected in parallel in the above embodiment, the present invention is not limited to this structure. At least during regenerative braking, the field windings 4b and 5b may be connected in parallel. Therefore, by switching means such as an electromagnetic switch that switches during regenerative braking, the field windings 4b and 5b can be connected only during regenerative braking. It may be configured to be connected in parallel.

[0017]

[Effect of device]

 According to the present invention, as described in detail above with reference to the embodiments, a regenerative current can be applied to both DC motors, so that good regenerative braking can be achieved without causing vibration of the vehicle body. .

[Brief description of drawings]

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

FIG. 2 is an explanatory view conceptually showing a two-motor battery forklift truck to which the embodiment is applied.

FIG. 3 is a circuit diagram showing a conventional technique.

[Explanation of symbols]

 1, 2 wheels 4, 5 DC motor 4b, 5b field winding

Claims (2)

[Scope of utility model registration request] 1. In a control circuit of an electric vehicle, wherein two DC motors are configured to drive left and right wheels respectively, and a circuit for regenerative braking is provided, each field winding of the DC motors is connected in parallel. A control circuit for an electric vehicle that is connected. 2. A control circuit of an electric vehicle, wherein two DC motors are configured to drive left and right wheels respectively, and a circuit for regenerative braking is provided. Each field winding of the DC motor is regenerated. A control circuit for an electric vehicle, characterized in that the control circuits are connected in parallel to each other via switch means that is switched during braking.