JPH06245564A - Motor controller - Google Patents

Abstract

PURPOSE:To protect a semiconductor switch from an overvoltage generated in a motor. CONSTITUTION:A battery E is connected through contactor 1 to power transistors Q1 to Q6 for controlling a motor M. A second contactor 3 is connected in parallel to the contactor 1. A current detector 4 is inserted and connected between the contactor 1 and the power transistors Q1 to Q6. The current detector 4 detects a current flowing from the motor M to the battery E by the induced power of the motor M and turns on the second contactor 3 by the excitation control of the coil 3a of the second contactor 3. The induced power generated in the motor M is charged in the battery E through the second contactor 3, and the power transistors Q1 to Q6 are protected from overvoltage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control device.

[0002]

2. Description of the Related Art Conventionally, for example, a motor for driving a vehicle, that is, a motor used in an electric vehicle is driven by a battery as a motor driving power source mounted on the vehicle. FIG. 5 shows an electrical configuration for driving and controlling the motor. As shown in FIG. 5, the contactor 1 is provided so that high voltage and high current are not applied to the motor M from the battery E when the electric vehicle is not used. Further, the contactor 1 prevents sparks from being generated at the terminals of the battery E when the battery E is connected to the motor M when the charger is connected to the battery E to charge the battery E. There is also. The contactor 1 has a built-in coil 1a for turning the contactor 1 on and off.

The motor M is a three-phase induction motor, and power transistors Q1, Q2, Q3, Q4, Q5, Q6 as semiconductor switches are provided at respective terminals of the motor M.
Is connected to a three-phase bridge circuit (hereinafter referred to as an inverter). The emitter side of the power transistor Q1 and the collector side of the power transistor Q4 are connected, and the motor M is connected between them. The emitter side of the power transistor Q2 and the collector side of the power transistor Q5 are connected, and the motor M is connected between them. The emitter side of the power transistor Q3 and the collector side of the power transistor Q6 are connected, and the motor M is connected between them. Each power transistor Q1-Q
Diodes D1 to D6 as flywheel diodes are connected between the emitter and collector of No. 6. The anodes of the diodes D1 to D6 are connected to the emitters of the power transistors Q1 to Q6. A pulse signal from a servo amplifier (not shown) is input to the bases of the power transistors Q1 to Q6, for example, according to the depression amount of an accelerator pedal (not shown).

The collector side of the power transistors Q1, Q2, Q3 is connected to the positive electrode of the battery E via the contactor 1. Power transistors Q4, Q5, Q6
The emitter side of is connected to the negative electrode of the battery E.

At both ends of the battery E, a key switch SW and a CPU 2 as a contactor drive control circuit are connected in series in parallel with the battery E. One end of the key switch SW is connected to the positive electrode of the battery E, and the other end is the CPU 2
It is connected to the. The coil 1a of the contactor 1 is connected to the CPU 2. Therefore, the key switch SW
Is a power switch for the CPU 2, and when the key switch SW is turned on, the coil 1a is excited and controlled according to a control program stored in the CPU 2 to turn on the contactor 1. Further, terminals T1 and T2 for connecting an external charger or the like are provided at both ends of the battery E.

In order to rotate the motor M, first, the key switch SW is turned on and the program of the CPU 2 is executed. Then, the CPU 2 excites the coil 1a of the contactor 1 to turn on the contactor 1. From this state, the pulse signal from the servo amplifier changes according to the amount of depression of the accelerator pedal to each power transistor Q1 of the inverter.
~ Is input to the base of Q6. Power transistor Q1
On-off control is performed by Q8 on the basis of the input pulse signal, and the direct current of the battery E is converted into an alternating current by the inverter and added to the motor M to rotate. The electric vehicle runs by the rotation of the motor M.

When the accelerator pedal is stopped while the vehicle is traveling or the vehicle is traveling downhill, the actual rotational speed of the motor M becomes higher than the target rotational speed of the motor M based on the pulse signal. Therefore, the motor M serves as a generator, and the voltage applied to the emitters of the power transistors Q1 to Q3 increases due to the induced power (back electromotive force). The voltage applied to the power transistors Q1 to Q3 does not become an overvoltage because the current flows through the diodes D1 to D3 and the contactor 1 connected to the power transistors Q1 to Q3 to charge (regenerate) the battery E. Therefore, the power transistors Q1 to Q6 are not destroyed due to the overvoltage due to the induced power generated in the motor M.

The method of regenerating the induced electric power induced by the motor M to charge the battery E as described above is more effective in energy than the method shown in JP-A-2-74182 in which the induced electric power is consumed by a resistor. It is very advantageous to use.

[0009]

However, if the key switch SW is accidentally turned off while the electric vehicle is running, the power of the CPU 2 may be turned off and the contactor 1 may be turned off. Further, the contactor 1 may be turned off when the CPU 2 is reset by external noise. At this time, induced energy is generated by the energy stored in the motor M, and the power transistors Q1 to Q
The voltage applied to the terminal 6 increases. However, since the contactor 1 is off, the induced electric power generated in the motor M is not charged in the battery E. Therefore, the voltage applied to the terminals of the power transistors Q1 to Q6 may exceed the withstand voltage of the power transistors Q1 to Q6 and may be destroyed by the overvoltage.

The object of the present invention is to protect the semiconductor switch for controlling the electric power supplied to the motor from overvoltage by storing the induced electric power induced by the motor in the motor drive power supply even when the contactor is turned off. It is to provide a motor control device.

[0011]

According to a first aspect of the present invention, a motor, a semiconductor switch for controlling electric power supplied to the motor from a motor driving power source through a contactor that can be opened and closed, and an induction from the motor. A motor provided with a flywheel diode for regenerating the induced power generated in the motor drive power supply through the contactor, and a contactor drive control circuit for closing the contactor in the motor drive mode and opening the contactor in the motor stop mode. In the control device, a regenerative circuit for regenerating the induced electric power induced by the motor to the motor drive power source when the contactor is at least open is provided in parallel with the contactor.

According to the second aspect of the invention, the motor, the semiconductor switch for controlling the electric power supplied from the motor driving power source to the motor through the contactor which can be opened and closed, and the induced electric power induced from the motor. In a motor control device provided with a flywheel diode for regenerating a motor drive power supply through the contactor, and a contactor drive control circuit for closing the contactor in the motor drive mode and opening the contactor in the motor stop mode, A regenerative circuit is provided that closes the open contactor based at least on the induced power induced by the motor when the contactor is open.

[0013]

According to the first aspect of the invention, the regenerative circuit for regenerating the electromotive force induced by the motor to the motor drive power source is provided in parallel with the contactor, so that the motor is generated without the contactor. The induced electric power that is generated can be stored in the motor drive power supply through the regeneration circuit. As a result, the semiconductor switch that controls the electric power supplied to the motor can be protected and the induced electric power can be effectively used.

Further, according to the second aspect of the invention, the contactor which opens the regenerative circuit for regenerating the induced power induced by the motor to the motor drive power source based on the induced power induced by the motor is closed. By doing so, the induced power generated in the motor can be stored in the motor drive power supply via the contactor. As a result, the semiconductor switch that controls the electric power supplied to the motor can be protected and the induced electric power can be effectively used.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment embodying the present invention will be described below with reference to FIG. In the structure of the present invention, the same structure as that of the motor control device shown in FIG. 5 will be described using the reference numerals of the related art, and the description will be omitted, and a new structure will be described.

As shown in FIG. 1, a second contactor 3 as a regenerative circuit is connected to the contactor 1 in parallel. The second contactor 3 includes a second coil 3a for turning on / off the second contactor 3. A current detector 4 is inserted and connected between the contactor 1 and the inverter. One end of the current detector 4 is connected to the contactor 1, and the other end is connected to the power transistor Q1 of the inverter.
It is connected to the collector side of Q2 and Q3. The side of the current detector 4 connected to the contactor 1 is connected to the second contactor 3.

The current detector 4 is adapted to detect a current flowing in one direction, and is provided in a direction to detect a current flowing toward the contactor 1. The current detector 4 is connected to the coil 3a of the second contactor 3. The second contactor 3 is normally off (open circuit), and when the current is detected by the current detector 4, the second contactor 3
The coil 3a of the contactor 3 is excited and is turned on (closed).

Next, the operation of the motor control device thus constructed will be described. During normal traveling of the electric vehicle, the contactor 1 is in a drive mode, that is, the coil 1a is excited and controlled by the CPU 2 to be on (closed). Therefore, current flows from the battery E toward the collector side of the power transistors Q1, Q2 and Q3 of the inverter. A pulse signal from a servo amplifier (not shown) is input to the bases of the power transistors Q1 to Q6 to control the power transistors Q1 to Q6 to be turned on and off, and the direct current of the battery E is converted into an alternating current by the inverter and is applied to the motor M to rotate. . At this time, since the current detector 4 does not detect the current flowing from the motor M toward the battery E, the second contactor 3 remains off.

When the accelerator pedal is stopped while the vehicle is running, or when the vehicle is traveling downhill, that is, during regenerative operation, the voltage applied to the power transistors Q1 to Q6 rises due to the induced electric power generated by the energy stored in the motor M. To do. Current is generated by the induced power, and power transistors Q1 to Q
3 through the diodes D1 to D3 connected in anti-parallel to the contactor 1 toward the contactor 1. The current detector 4 is a motor M
The current flowing out is detected and the coil 3a of the second contactor 3 is excited and controlled. Therefore, the second contactor 3 is turned on, and the induced electric power generated in the motor M is charged in the battery E via the first contactor 1 and the second contactor 3.

At this time, if the key switch SW is accidentally turned off, the power of the CPU 2 is also turned off. Therefore, the coil 1a of the contactor 1 is no longer subjected to excitation control by the CPU 2, and the contactor 1 is in the stop mode, that is, off (open circuit). However, since the second contactor 3 is on,
The current flowing out from the motor M is detected by the current detector 4 to control the excitation of the coil 3a of the second contactor 3. Therefore, the second contactor 3 is not turned off, and the induced electric power generated in the motor M is charged in the battery E via the second contactor 3.

When the energy of the motor M is consumed and the voltage applied to the power transistors Q1 to Q6 decreases, no current flows from the motor M to the battery E.
Since the current detector 4 does not detect the current flowing toward the battery E, the coil 3a of the second contactor 3 is no longer subjected to excitation control. Therefore, the second contactor 3 is turned off.

As described above, in the motor control device of this embodiment, the second contactor 3 is provided in parallel with the contactor 1 and is turned on by the current flowing from the motor M toward the battery E, so that the motor M is induced. It is possible to protect the power transistors Q1 to Q6 from overvoltage by charging the battery E with the induced power generated via the second contactor 3.

The present invention is not limited to the above-mentioned embodiments, but may be modified as follows without departing from the spirit of the present invention. (1) In the above embodiment, the second contactor 3 is provided separately, but as shown in FIG.
Alternatively, the coils a and 1b may be incorporated, and one coil 1a may be controlled by the CPU 2 and the other coil 1b may be controlled by the current detector 4. Further, the CPU 2 and the current detector 4 may be connected in parallel to the coil 1a of the contactor 1 as shown in FIG. In any of the above cases, the contactor 1 is controlled to be turned on by either the CPU 2 or the current detector 4.

(2) In the above embodiment, the second regeneration circuit is used.
Although the contactor 3 is used, a semiconductor switch such as a thyristor may be used. (3) In the above embodiment, the current detector 4 detects the current flowing from the motor M toward the battery E to turn on the second contactor 3. However, as shown in FIG. 4, the diode D7 as a regenerative circuit is used. May be connected in parallel with the contactor 1 such that the cathode side of the diode D7 is on the battery E side. In this case, the diode D7 is selected and used to withstand the power supply voltage and the like.

(4) In the above embodiment, the present invention is applied to the control device of the induction motor, but it may be applied to the control devices of DC motor, brushless motor and various other motors. (5) In the above embodiment, the current detector 4 detects the current flowing from the motor M toward the battery E to turn on the second contactor 3. However, the collector side of the power transistors Q1, Q2 and Q3 and power Transistor Q
The first contactor 1 may be turned on by detecting the voltage on the emitter side of 4, Q5 and Q6.

[0026]

As described in detail above, according to the motor control device of the present invention, the regenerative circuit for regenerating the electromotive force induced by the motor to the motor drive power source is provided in parallel with the contactor. The excellent effect that the induced power generated in the motor can be stored in the motor drive power supply via the regenerative circuit, the semiconductor switch that controls the power supplied to the motor can be protected, and the induced power can be effectively used. Play.

Further, the regenerative circuit for regenerating the induced electric power induced by the motor to the motor drive power supply is closed based on the induced electric power induced by the motor to close the contactor, thereby causing the induction generated in the motor. The electric power can be stored in the motor drive power supply via the contactor, the semiconductor switch for controlling the electric power supplied to the motor can be protected, and the induced electric power can be effectively used. .

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a motor control device according to an embodiment of the present invention.

FIG. 2 is a main part of a circuit diagram showing another example of the present invention.

FIG. 3 is a main part of a circuit diagram showing another example of the present invention.

FIG. 4 is a main part of a circuit diagram showing another example of the present invention.

FIG. 5 is a circuit diagram showing a conventional motor control device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Contactor, 2 ... CPU as a contactor drive control circuit, 3 ... 2nd contactor as a regeneration circuit, 4 ...
Current detector, E ... Battery, M ... Motor

Claims (2)

[Claims] 1. A motor, a semiconductor switch for controlling electric power supplied from a motor drive power source to a motor via a contactor that can be opened and closed, and induced electric power induced from the motor to a motor drive power source via the contactor. In a motor control device provided with a flywheel diode for regenerating and a contactor drive control circuit that closes the contactor in the motor drive mode and opens the contactor in the motor stop mode, a motor is provided at least when the contactor is open. A motor control device comprising a regenerative circuit for regenerating the electromotive force induced by the motor drive power source in parallel with the contactor. 2. A motor, a semiconductor switch for controlling the electric power supplied from the motor drive power source to the motor via a contactor that can be opened and closed, and an induced electric power induced from the motor to the motor drive power source via the contactor. In a motor control device provided with a flywheel diode for regenerating and a contactor drive control circuit that closes the contactor in the motor drive mode and opens the contactor in the motor stop mode, a motor is provided at least when the contactor is open. A motor control device comprising: a regenerative circuit that closes the contactor that is open based on the induced power induced by the motor.