JPS6331401A - Controller for electric motor car - Google Patents

Abstract

PURPOSE:To prevent a controlling resistance from being fused, by OFF-working a main circuit switch when the temperature of the speed controlling resistance is continuously kept higher than a specified one for a specified time or longer. CONSTITUTION:On normal running, current is conducted to the relay coil of a main circuit switching relay 2 via a main switch 7, an accelerator switch 8, and the contact of a relay 9, and the contact of the relay 2 is closed, and current is conducted to a DC motor 1 via the resistance wire 5 of a speed controlling resistance 3. On the other hand, a temperature at or near the resistance 3 is detected by a temperature detecting sensor 10, and when the detected temperature comes to a temperature higher than a specified one, then an alarm lamp 12 is lit by a control circuit 11. Besides, when this state is continuously set for a specified or longer time, then current is conducted to a transistor 13, and the contact of the main circuit switching relay 2 is ON-worked.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a control device that controls the speed of an electric vehicle such as an electric golf car using an electric motor as a driving source, using a resistance type side rail. , 1) relates to prevention of overheating of the resistor.

(Prior art) Various types of speed control devices for electric vehicles have been known, such as resistance control, field control, and voltage control using a thyristor or transistor, but none of them are advantageous in terms of cost. Many resistance-controlled types are used.

In this resistance-controlled electric vehicle, taking into account that there are few opportunities to drive at intermediate speeds due to the purpose of use, especially in golf cars, etc., the resistance for speed control is generally controlled by the resistance caused by excessive load. The capacity and weight design is not sufficient to withstand use. For this reason, if the driving motor is locked and overloaded due to the golf car running onto a curb while driving at intermediate or medium-high speeds, a large current will flow through the main circuit. There was a risk that the resistor used for the series would generate abnormal heat and melt. In order to prevent this situation from occurring, it is important to make the capacity of the control resistor sufficiently large.As the capacity increases, the shape also becomes larger, requiring a large amount of installation space. is unsuitable, and furthermore, high 1iBl
There is a problem that it becomes ir/S and is not practical.

(Objective of the Invention) The present invention solves the above-mentioned problems, and is an electric vehicle capable of detecting when a control resistor generates heat due to overload and preventing it from melting. The purpose is to provide a control device for.

(Structure of the Invention) The present invention is directed to an electric vehicle in which a traveling drive motor is connected to a power source via a speed control resistor and a main circuit switch.
The device includes a temperature detection sensor that detects the temperature of the speed control resistor or its vicinity, and a warning notification means that drives a warning notification when the detected temperature becomes higher than a predetermined temperature based on a detection signal from the sensor. 1111 circuit, and a drive circuit that opens the main circuit switch when the above state continues for a predetermined period of time or more.

With this configuration, it is possible to notify that the resistor is tending to overheat, and if overheating continues, it is possible to cut off the power supply to the main circuit including the motor.

(Example·) An embodiment of the present invention will be described below with reference to the drawings.

A DC motor 1 for running drive is connected to a battery 4 which is a power source through the contacts of a main circuit switching relay 2 which is a main circuit switch and a V1 resistor 3 for speed control. Therefore, it consists of a resistance wire 5 having a plurality of notches a to f, and a changeover switch 6 that is linked to an accelerator pedal that is in contact with one of the notches. The relay coil of the main circuit opening/closing relay 2 is connected to the battery 4 through the contacts of a main switch 7, an accelerator switch 8, and a normally closed relay 9, which will be described later.

Further, a temperature detection sensor 10 is provided to detect the temperature of the speed control resistor 3 or a temperature in the vicinity thereof.
The output of the temperature detection sensor 10 is input, and when the detected temperature becomes higher than a predetermined temperature, the output is used to drive a warning lamp 12 as a notification means to notify the driver of this fact. The control circuit 11 controls the energization of the relay coil of the normally closed relay 9 inserted into the relay circuit of the main circuit switching relay 2 when the above state continues for a predetermined period of time or more. It also generates a control output for the transistor 13. That is, the transistor 13 and the normally closed relay 9 constitute a drive circuit for opening the main circuit switching relay 2 when the speed control resistor 3 continues to generate heat.

To explain the operation of the above circuit configuration, during normal driving, the main switch 7 and the accelerator switch 8 are turned on, and the relay coil of the main circuit opening/closing relay 2 is energized via these switches and the contacts of the normally closed relay 9. The contact point of is closed, and the DC motor 1 is energized via the resistance wire 5 from either of the notches a to f that are in contact with the changeover switch 6 linked to the accelerator pedal of the speed control resistor 3, and the electric vehicle is driven to run. .

Normally, when playing golf, etc., there are few opportunities to travel at intermediate speeds, and the vehicle is often driven at high speed notches e or f, and in that case, the resistance value of the speed υ1a resistor 3 is small, so A relatively large current flows through the circuit.

Here, the electric vehicle hits some kind of obstacle, and the DC motor 1
When the main circuit is locked, a large overcurrent flows through the resistance wire 5 inserted into the main circuit. Since golf cars and the like are used with few opportunities to run at intermediate speeds, the resistance wire 5 does not have a sufficient capacity ff1l to withstand continuous use under excessive load. Therefore, the resistance wire 5 may generate heat and may be fused.

However, in the present invention, the temperature of the resistor 3 or its vicinity is detected by the temperature detection sensor 10, and when the detected temperature becomes higher than a predetermined temperature, the control circuit 11 lights up the warning lamp 12 and alerts the driver. Warn to that effect. Furthermore, when this state continues for more than a predetermined time, an output is generated that makes the transistor 13 conductive, and the conduction of the transistor 13 causes the contacts of the normally closed relay 9 to be opened, thereby causing the excitation circuit of the relay coil of the main circuit switching relay 2. becomes an oven, and the contacts of the main circuit switching relay 2 open and cut off the main circuit. Therefore, the speed control resistor 3 and the DC motor 1 are no longer energized, and the resistor 3
heat generation is prevented.

Further, when the temperature of the resistor 3 decreases, the conduction of the transistor 13 by the υ1t[1 circuit 11 is cut off, so the normally closed relay 9 returns to its normal state, and the excitation circuit of the relay coil of the main circuit opening/closing relay 2 is excited again. The contact closes and the main circuit is automatically energized again, allowing the electric vehicle to resume running.

The driver can know that the electric vehicle is overloaded when the warning lamp 12 lights up, and the driver can continue driving the electric vehicle by removing obstacles that cause the overload. Alternatively, by turning off the accelerator switch 8 at the driver's will and opening the main circuit open/close relay 2, the power to the main circuit is temporarily cut off and driving is interrupted for a short period of time. By doing so, it is only necessary to wait for the heat dissipation of the heated speed υ1t111 resistor 3 to return to the running state again.

By carrying out the above-described operation, it is possible to prevent a situation in which the resistance wire 5 of the speed control resistor 3 is overheated and melted, making it impossible for the electric vehicle to run.

(Effects of the Invention) As described above, according to the present invention, the temperature of the speed control resistor or its vicinity is detected by the temperature detection sensor, and when the temperature of the resistor becomes overheated, the notification means is activated, and the If this continues, the power to the main circuit is cut off, so even if the speed control resistor becomes overheated in an overload condition, it will be prevented from melting, making it impossible for the electric vehicle to run. It is possible to prevent this from happening. Especially in electric golf cars, etc., there are few opportunities to run at intermediate speeds, so the speed control resistor is not sufficient in terms of weight, installation space, cost, etc. to withstand continuous use under excessive load. Even under such conditions, it is possible to reliably prevent melting and damage due to heat generation of the resistor during overload conditions.

[Brief explanation of the drawing]

The drawing is an electrical circuit diagram according to an embodiment of the present invention. 1... DC motor, 2... Main circuit switching relay (main circuit switch), 3... Speed control resistor, 4... Battery (power supply), 9... Normally closed relay (drive circuit) ), 10・
...Temperature detection sensor, 11...Control circuit, 12...
Warning lamp (notification means).

Claims (1)

[Claims] 1. In a control device for an electric vehicle in which a travel drive motor is connected to a power source via a speed control resistor and a main circuit switch,
A temperature detection sensor that detects the temperature of the speed control resistor or its vicinity, and a control circuit that drives a warning notification means when the detected temperature becomes higher than a predetermined temperature based on the detection signal of this sensor. and a drive circuit that opens the main circuit switch when the state continues for a predetermined period of time or more.