JPS591361Y2 - electric car control device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an electric vehicle control device using a chopper device.

In particular, the present invention provides a solution to the problems that arise when implementing a circuit system in which all or part of the main resistor is connected in parallel to the chopper device in an electric vehicle that uses a chopper device to apply regenerative or dynamic braking. It is something to do.

That is, conventionally, an iron chromium alloy or a nickel chromium alloy has been generally used as a resistor material for a main resistor for passing a large current such as a main circuit current.

However, since these alloy materials are ferromagnetic or magnetic materials, when they are used in a resistor connected in parallel to a chopper device, a square wave current due to repeated on and off flows through this resistor. The magnetostrictive vibration of the resistive material generates an abnormally large noise, which is a major hindrance to its use in electric vehicles.

This becomes a big problem when using naturally air-cooled resistors.

As a countermeasure to this problem, it is possible to use a stainless steel plate that is a non-magnetic material, such as 18-8 stainless steel material. However, when stainless steel material is used as a resistor, the temperature coefficient of the specific resistance value is extremely large, and the temperature at 400°C As the resistance increases, the specific resistance value increases by about 1.4 to 1.5 times, making it unsuitable for use as a resistor that is required to always maintain a constant resistance value.

If a resistor made of this stainless steel material is dared to be applied to the parallel connection circuit of the chopper device, the following problems will occur.

Generally, when using a DC motor and trying to apply dynamic or regenerative braking while controlling the current flowing through the motor using a chopper, in order to maintain a constant braking force, the motor current must be controlled regardless of the speed. , must be kept approximately constant, and for this reason, the peak value of the current flowing through the chopper and the chopper parallel resistor is maintained at an approximately constant value.

However, when the resistance value of the chopper parallel resistor increases as the temperature rises due to energization, the peak value of the terminal voltage of the resistor increases in proportion to the increase in the resistance value, and eventually A problem arises in that the chopper device may be destroyed due to overvoltage application.

This invention eliminates the above-mentioned drawbacks when using a resistor made of a non-magnetic material such as stainless steel as a chopper parallel resistor using a relatively simple method, and puts it into practical use. This makes it possible.

Figure 1 shows an example of the main circuit connection diagram for the present invention.
In the figure, 1 is a main motor having an armature A and a field winding F, 2 is a thyristor chopper device, and 3 is a chopper device 2.
The main resistor 4 is connected in parallel with the main resistor 3, and 4 is a partial resistance short-circuit contactor provided in the short-circuit circuit for short-circuiting the main resistor 3.

It goes without saying that the contactor 4 is not limited to a mechanical one, and may be another switching element such as a semiconductor switch.

The resistance value of the main resistor increases as the temperature of the resistor increases, but when the resistance value increases to a certain extent, it is necessary to close the contactor 3 to suppress the increase in the chopper parallel resistance value. On the other hand, if the resistor cools while the resistor is not energized and the resistance value drops, it is necessary to keep the contactor open. ) can be performed automatically using appropriate and simple equipment.

FIG. 2 shows a block diagram of an embodiment of the present invention.

In the figure, 5 is a temperature sensor provided on the resistor of the main resistor 3, 6 is a temperature comparison circuit, and 7 is a contactor control circuit.

Further, arrows shown with dashed lines indicate the flow of signals or commands.

In FIG. 2, a resistor temperature sensor 5 is installed at or in the very vicinity of the resistor in a resistance section that is not short-circuited by the contactor 4, and detects the temperature rise due to energization of the main resistor 3. Always detect.

The specific resistance value of stainless steel material increases compared to the temperature rise value of the stainless steel material, so how many temperature rises will the resistance value increase to the limit of the allowable main resistance value when a contactor is not inserted? It is checked in advance whether the first temperature value is reached, and the temperature comparison circuit 6 detects whether the first temperature value is reached.

If the temperature exceeds the first temperature value, the contactor 4 is closed by a contactor closing command Sk from the contactor control circuit 7 based on the detected output, thereby shorting out the increase in the main resistance value.

In addition, in order to keep the main resistance value within the expected allowable range and to prevent contactor closing and opening operations from becoming unnecessarily frequent, the first
Appropriately set a second temperature value that is slightly lower than the temperature value of
When the detected temperature becomes lower than the second temperature value, this is detected by the temperature comparator circuit 6, and its output causes the contactor resistance circuit 7 to release the contactor closing command Sk and close the contactor 4. Make it open.

As described above, according to the present invention, it is possible to use a main resistor made of stainless steel as a chopper parallel resistor by simply adding a relatively simple device, and it is possible to use a chopper resistor without noise problems. This means that a control method can be realized.

In addition, in the above explanation, the set value of the temperature sensor is set to one stage of on/off to control one contactor, but it is also possible to sequentially short-circuit each section of the main resistor using multiple contactors. At the same time, the set value of the temperature sensor is set in several stages, and the contactor is automatically closed one by one each time the detected temperature value exceeds each temperature setting stage. You can also do this.

Furthermore, the number of temperature detectors is not limited to one, but a plurality may be provided depending on the arrangement of the main resistors, and the average value of their outputs may be compared to see if it exceeds a predetermined set value. Needless to say.

[Brief explanation of drawings]

1 and 2 show an embodiment of the present invention, with FIG. 1 being a main circuit connection diagram and FIG. 2 being a control block diagram thereof. Note that the same reference numerals in the figures indicate the same parts. In the figure, 2 is a chopper device, 3 is a main resistor, 4 is a contactor,
5 is a temperature detector, 6 is a temperature comparison circuit, and 7 is a contactor control circuit.

Claims (1)

[Scope of utility model registration request] A chopper device for controlling the main circuit current of an electric vehicle, a main resistor connected in parallel to this chopper device, a switching element provided in a short circuit circuit that shorts a part of this main resistor,
a temperature detector for detecting the temperature of the resistor at a location other than the resistance section short-circuited by the short-circuited circuit of the resistor constituting the main resistor; A temperature comparison circuit for comparing a second temperature value lower than the first temperature value, and a switching element configured to close the short circuit if the comparison absolute of the temperature comparison circuit is equal to or higher than the first temperature value. An electric vehicle control device comprising: a control circuit that gives a command to the switching element to operate the switching element and maintain the operating state of the switching element until the temperature drops below the second temperature value.