JPS59144303A - Motor controller of electric motor coach - Google Patents

Abstract

PURPOSE:To improve the efficiency by shortcircuiting a chopper circuit when the fact that a conductive state from a signal for operating a chopper circuit is the prescribed time or longer is detected. CONSTITUTION:When the level of a rotation command signal V1 increases higher than a quasi-triangular wave V2 by the operation of an accelerated, a pulse having a width in response to the level of the signal V1 is outputted from a comparator 3. When the output Vs of a current detecting resistor Rs is a reference voltage V4 or lower, the output of a comparator 6 is high level, and an AND circuit 4 applies the output of a comparator 5 to a motor drive circuit 5. When the level of the rotation command signal V1 becomes always the wave V2 or higher, the output V7 of a delay circuit 7 exceeds a reference voltage V9. Accordingly, the output of a comparator 8 becomes high level. In this manner, a relay 9 is energized, a relay contact 9a is closed to shortcircuit the motor drive circuit 5.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric motor control device for an electric vehicle, and more particularly, a control device having a chopper drive circuit is operated by combining a relay with a chopper circuit, and the relay contacts are short-circuited when energized other than during switching operation. , relates to an electric motor control device for an electric vehicle that reduces voltage drop in the forward direction.

The chopper drive circuit, especially the rotation control device G, is as follows:
Normally, in order to obtain maximum rotation, the final stage is fully conductive, but the voltage drop in the forward direction of the semiconductor used in the final stage is a major cause of loss in the device. In other words, when the semiconductor is fully conductive, the voltage drop across the semiconductor is considerably larger than that of a relay or the like. Among them, some transistors have a voltage drop of about 2 cm, and power transistors have a particularly significant voltage drop. For example, if a current of 50 A flows through the transistor, the power consumption is 1 oOW, which is a loss in the device and causes heat generation in the semiconductor itself.

When a chopper circuit and a relay are used together, it is customary to use a switch notching circuit to operate the relay when the rotation command signal reaches its maximum. In this case, once the load is fully opened, the current limiting circuit etc. will automatically operate even if the load becomes large, and it will not be possible to return to chiyo knocking, so you will need to rely on other protection circuits such as a breaker, or limit the load. This makes it difficult to utilize the full capacity of the drive device.

JP-A No. 54-622o “Electric motor control device for electric vehicles”
proposed a control device that short-circuits the chopper circuit by switching the specified value of the chopper energization rate between when driving on a flat road and when driving on an uphill road, but it is said that if the switching operation is not performed reliably, the chopper function will be damaged. There were drawbacks.

In particular, an object of the present invention is to operate a relay in combination with a chopper circuit of a control device having a chopper drive circuit, to short-circuit the relay contacts when energized other than during switching operation, and to reduce the voltage drop without changing the normal chopper function. It is an object of the present invention to provide an electric motor control device for an electric vehicle that can reduce the amount of noise and improve efficiency.

To achieve the above object, the present invention provides an electric motor control device for an electric vehicle that controls the speed of an electric motor using a chopper circuit whose pulse width is variable in accordance with the level of a rotation command voltage. A conduction state detection circuit that detects that the chopper circuit is in a conductive state for a predetermined period of time or more and orders an output from a signal that operates the chopper circuit, and a semiconductor element that controls the speed of the motor of the chopper circuit are connected in parallel. and a relay that bypasses the semiconductor and supplies current to the motor based on the output of the conduction state detection circuit.

According to the above structure, the object of the present invention can be completely achieved.

Hereinafter, the present invention will be explained in more detail with reference to the drawings and the like.

FIG. 1 is a circuit diagram showing an embodiment of the electric motor control device for an electric vehicle according to the present invention, and FIG. 2 is a waveform diagram for explaining the operation.

The rotation command signal generator 1 is interlocked with the accelerator and is for generating a rotation command signal v1, and the output v1 of the rotation command signal generator 1 is connected to the non-inverting input terminal of the comparator 3. The pseudo triangular wave generation circuit 2 generates a pseudo triangular wave signal v2.
This is to generate the pseudo triangular wave generator circuit 2.
The output v2 of is connected to the inverting input terminal of the comparator 30. Comparator 3 outputs a PW corresponding to the level of rotation command signal v1.
The comparator 3 outputs an M waveform v3, and the output v3 of the comparator 3 is connected to one input terminal of the AND circuit 4. The output v6 of the AND circuit 4 is branched and one side is connected to the motor drive circuit 5.

The motor drive circuit 5 includes transistors TR1 and TR2, and is a circuit that rotates the motor M according to the output v6 of the AND circuit 4. When the motor drive circuit 5 becomes conductive,
A circuit including battery B, main switch SW, motor M, and current detection resistor Rs is formed to rotate motor M.

The output vs of the current detection resistor Rs is connected to the inverting input terminal of the comparator 60, and the reference voltage v is connected to the non-inverting input terminal of the comparator 6.
4 is connected. The current detection resistor Rs is a resistor for detecting the current flowing through the final stage transistor TR2 of the motor drive circuit 6 in the form of voltage. Output v6 of comparator 6
is connected to the other input terminal of the AND circuit 4. When the output vs of the current detection resistor Rs exceeds the reference voltage v4, the output of the comparator 6 becomes low level, and energization to the motor drive circuit 5 is blocked.

The conduction state detection circuit is a delay circuit 7. It is composed of a comparison circuit 8, etc., and a signal v6 that operates the Chiyo-Tsuba circuit.
This circuit detects that a conductive state remains for a certain period of time or more and generates an output.

The other branched output of the AND circuit 6 is connected to a delay circuit 7. The delay circuit 7 is a circuit for delaying the AND circuit 40 output v6. The output v7 of the delay circuit 7 is connected to the non-inverting input terminal of the comparator 8.
A reference voltage v3 is connected to the inverting input terminal of. The output of comparator 8 is connected to the base of transistor TR.

The l transistor TR is for operating the relay 9.

A contact 9a of the relay 9 is connected in parallel to the transistor TR2 that controls the speed of the motor M of the chopper circuit, and when the relay 9 is actuated by the output v8 of the conduction state detection circuit, the contact 9a is closed and the transistor TR2 is activated. This is for supplying current to the motor M by bypassing it.

Next, the operation of the electric motor control device for an electric vehicle according to the present invention will be explained.

When the accelerator is not operated, that is, when the level of the rotation command signal v1 is lower than the pseudo triangular wave v2, the output (3) of the comparator 3 is at a low level and does not enter the chopper region and is turned off, and the subsequent circuit does not operate.

When the accelerator operation causes the level of the rotation command signal v1 to be higher than the pseudo triangular wave v2, a pulse having a width corresponding to the level of the rotation command signal v1 is output from the comparator 3.On the other hand,
Since the motor drive circuit 5 is not yet operating, the output vs of the current detection resistor Rs reaches the reference voltage v4 of the comparator 6. Since the output 5 of the comparator 6 is at a high level, the AND circuit 4 performs the comparison. The output of the device 3 is connected to a motor drive circuit 5.

The output v6 of the AND circuit 4 is sent to the comparator 8 via the delay circuit 7.
is man-powered. Since the output 6 of the AND circuit 4 is still smaller than the reference voltage 9 (V7 in FIG. 2), the output of the comparator 8 is at a low level (Ve in FIG. 2). Therefore, relay 9 remains off and transistor TR2 is not shorted (tl).

At this time, if a voltage exceeding the reference voltage 4 is detected from the current detection resistor Rs, the output of the comparator 6 becomes a low level, and the AND circuit 4 becomes a low level G, so that regardless of the output v3 of the comparator 3. The device is protected from overcurrent by blocking the power supply to the motor M.

When the level of the rotation command signal v1 is always higher than the pseudo triangular wave v2, that is, when the output of the rotation command signal v1 exceeds the chopper region and becomes fully conductive, the output 7 of the delay circuit 7 exceeds the reference voltage v9. Therefore, the output of the comparator 8 becomes NO\IREHEL (FIG. 2 v6). Therefore, relay 9 is turned on and transistor T R2
The motor M can be driven without a voltage drop across the transistor TR2.

As the load increases, a current limiting circuit (not shown) operates,
When the level of the output v1 of the rotation command voltage generator 1 decreases,
Since the level of the rotation command signal v1 becomes lower than the pseudo triangular wave v2 and the output v7 of the delay circuit 7 becomes lower than the reference voltage v9, the relay 9 is released. Therefore, a pulse having a width corresponding to the level of the rotation command signal (1) is output from the comparator 3, and the motor M is driven by the motor drive circuit 5.

As explained in detail above, according to the present invention, a relay is provided in parallel to the chopper circuit, and the relay contacts are short-circuited only when energized other than switching operation, so that the advantages of the conventional chopper circuit can be utilized as is, and the relay can be used to increase efficiency. You can improve your performance.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the electric motor control device for an electric vehicle according to the present invention, and FIG. 2 is a waveform diagram for explaining the operation. ■... Rotation command signal generator 2... Pseudo triangular wave generator 3... Comparator 4... AND circuit 5...
Motor drive circuit 6...Comparator 7...Delay circuit
8... Comparator 9... Relay 9a.
...Relay contact TR,, TR2...Transistor Rs...Current detection resistor M...Motor B...Hasoteri patent applicant Suzuki Motor Co., Ltd. agent Patent attorney Hisashi Inoro

Claims (1)

[Claims] In a motor control device for an electric vehicle that controls the speed of an electric motor using a chopper circuit whose pulse width is variable in accordance with the level of a rotation command voltage, it is detected from a signal for operating the chopper circuit that a conductive state has been present for a certain period of time or more. A conduction state detection circuit that generates an output is connected in parallel to a semiconductor element that controls the speed of the motor of the chopper circuit, and the output of the conduction state detection circuit bypasses the semiconductor and supplies current to the motor. What is claimed is: 1. A motor control device for an electric vehicle, comprising a relay that supplies