JPH07194156A - Controller for motor - Google Patents

Abstract

PURPOSE:To secure the normal operating state of a motor even when such a large-current requiring state that the load of the motor becomes larger, and so on, occurs immediately after the motor is driven by connecting one end of a dynamic brake circuit to the (-) side of a DC power source. CONSTITUTION:A charge pump is constituted by providing a power source Vdrv for the driving circuit DRV1 of a switching element SW1 connected to the (-) side of a DC power source Vdc, a capacitor C1 used as the power source of the driving circuit DRV1 of a switching element SW2, and a diode D2 which connects the (+) side of the capacitor C1 to the (+) side of the power source Vdrv for the driving circuit DRV1 of the switching element SW1 connected to the (-) side of the power source Vdc. In addition, three wires connected to the output side of an inverter circuit are connected to the (-) side of the DC power source Vdc through a resistor R1 or one end of a dynamic brake circuit constituted of a relay RY1 for direct short circuit is connected to the (-) side of the power source Vdc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric motor control device used in a device requiring a drive circuit by an electric motor in an industrial machine such as a robot.

[0002]

2. Description of the Related Art FIG. 3 illustrates a conventional motor drive device (1). Two switching elements SW connected in series between the positive and negative sides of the DC power supply Vdc in FIG.
1, SW2, three sets of six switching elements in total, six rectifying elements D1 connected in anti-parallel thereto, and a drive circuit DRV1 for these switching elements, in an inverter circuit, the negative side of the DC power supply. In order to charge the power source Vdrv for the drive circuit of the switching element SW1 connected to and the capacitor C1 used as the power source for the drive circuit of the switching element connected to the + side of the DC power source, the + side of this capacitor C1 And the power source V for the drive circuit of the switching element SW1 connected to the negative side of the power source
For the purpose of short-circuiting the charge pump circuit composed of the diode D2 connecting the + side of the capacitor C1 as the cathode between the + side of the drv and the three lines connected to the output side of the inverter circuit via the resistor R1 or directly. It consisted of a dynamic brake circuit that consisted of relays (or other components that could fulfill their role).

In FIG. 3, the power source for the drive circuit of the three switching elements SW1 connected to the negative side of the DC power source Vdc is Vdrv, and the three switching elements SW2 connected to the + side of the DC power source Vdc are connected. The power supply is also a diode D when the switching element SW1 is turned on from Vdrv.
The capacitor C1 is charged via 2 The relay RY1 which short-circuits the output via the resistors R1 and R1 on the output side of the inverter circuit is used for emergency stop of the electric motor connected to the output side of the inverter circuit. A current detector may be inserted between the output of the inverter circuit and the electric motor in order to detect the electric current flowing through the electric motor, but it is omitted from the description because it is irrelevant to the gist of the present invention.

FIG. 4 shows a conventional motor drive device (2). The capacitor C1 used as the power supply for the drive circuit of the switching element SW1 connected to the + side of the DC power supply Vdc has a diode D from the + side of the DC power supply Vdc.
3 and the electric motor drive device (1) according to the prior art shown in FIG. 3, except that the electric charge is charged by the resistor R2 connected in series with the diode.

[0005]

However, in the prior art, when the electric motor is not driven, that is, when the six switching elements SW1 and SW2 are not operating, the power source is for driving the switching element SW2. If the capacitor C1 is not charged with electric charge and the driving of the electric motor is started in this state, the load of the electric motor becomes large immediately after the driving is started. For example, when a large current is required, the + side of the DC power supply Vdc Since the switching element SW2 connected to is not sufficiently turned on, normal operation cannot be ensured or it may be destroyed. Also,
In order to avoid this, some kind of means is used to turn on the switching element SW1 connected to the negative side of the DC power source, or
Alternatively, it is necessary to charge the capacitor C1 by another method, which requires various additional circuits.

[0006]

A dynamic brake circuit is constructed as an emergency stop device of an electric motor by a relay RY1 intended to short-circuit three wires connected to the output side of an inverter circuit via a resistor R1 or directly. The circuit configuration is such that one end is connected to the negative side of the DC power supply.

Alternatively, one or two wires connected to the output side of the inverter circuit are short-circuited via the resistor R1 or directly to the negative side of the DC power supply Vdc and the relay RY1 to form a dynamic brake circuit.

[0008]

[Function] By operating the relay RY1, the capacitor C
One of the terminals 1 is connected to the negative side of the DC power source via the resistor R1. As a result, the + side of the capacitor C1 is charged from the power supply Vdrv for the switching element SW1 on the − side of the main circuit DC power supply Vdrc in the circuit of the embodiment of the present invention through the diode D2. 2, in the circuit of the second embodiment of the present invention, a diode D3 and a resistor R connected in series to this diode are provided from the + side of the main circuit DC power supply Vdc.
Charged via 2.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. Two switching elements SW1 and SW2 connected in series between the + side and the-side of the DC power supply Vdc, a total of six switching elements, and six rectifying elements D1 connected in antiparallel thereto. And a drive circuit DRV1 for these switching elements
The inverter circuit is composed of. DC power supply V
Using the power supply Vdrv for the drive circuit DRV1 of the switching element SW1 connected to the − side of dc, the DC power supply Vd
The capacitor C1 used as a power supply for the drive circuit DRV1 of the switching element SW2 connected to the + side of c has a power supply Vdrv for the drive circuit of the switching element connected to the + side of this capacitor and the − side of the DC power supply Vdc. It charges through the diode which connects between the + sides as the cathode of the + side of the capacitor. As a method of charging the charge pump circuit, a relay RY1 for short-circuiting the three wires connected to the output side of the inverter circuit via a resistor (the resistance value may be 0) when the inverter circuit is not operating is used. By turning on, the capacitor C1 is charged. By turning off the relay RY1 immediately before operating the inverter circuit, the dynamic brake circuit configured by the resistor R1 and the relay RY1 is released, and the switching element SW1 connected to the − side of the DC power supply Vdc during operation of the inverter circuit. Capacitor C while is ON
1 can be charged. When the resistor R1 and the relay RY1 that form the dynamic brake circuit are connected to only two or one of the three outputs of the inverter circuit, that is, the resistor R1 and the relay RY1.
Similarly, the dynamic brake circuit is established even when the contacts of are two circuits or one circuit, and the charge pump also has three outputs when the relay RY1 is ON because the motor is connected to the output of the inverter. The wire is connected to the negative side of the DC power supply Vdc through a motor, and the capacitor C
Can be charged to 1.

FIG. 2 shows a second embodiment of the present invention. Switching element SW1 connected to + side of DC power supply Vdc
1 is the same as the embodiment of the present invention except that the capacitor C1 used as the power supply for the drive circuit is charged with the diode D3 from the + side of the DC power supply Vdc and the resistor R2 connected in series with this diode. Is.

[0012]

According to the present invention, the capacitor voltage of the charge pump can be secured when the motor is started to be driven by the motor control device equipped with the charge pump and the dynamic brake, and the load of the motor becomes large immediately after the driving. It is possible to ensure a normal operating condition even if the condition becomes necessary. In addition, the number of additional circuits for operating the charge pump before driving the motor is minimal.

[Brief description of drawings]

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

FIG. 2 is a circuit diagram of a second embodiment of the present invention.

FIG. 3 is an explanatory view of a motor drive device (1) according to a conventional technique.

FIG. 4 is an explanatory view of a motor drive device (2) according to a conventional technique.

[Explanation of symbols]

Vdc main circuit DC power supply Vdrv main circuit DC power supply − side switching element power supply SW1 main circuit DC power supply − side switching element SW2 main circuit DC power supply + side switching element DRV1 switching element drive circuit D1, D2, D3 diode R1, R2 resistor C1 capacitor RY1 relay

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Minoru Matsushima Minority 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. 72) Inventor Sachio Ueno 1006 Kadoma, Kadoma-shi, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (3)

[Claims] 1. A set of two switching elements connected in series between a + side and a − side of a DC power source, a total of six switching elements, and six rectifying elements connected in antiparallel thereto. , In an inverter circuit composed of these switching element drive circuits, a switching element drive circuit power supply connected to the negative side of the DC power supply and a DC power supply +
Between the positive side of the capacitor used as the power supply for the switching element drive circuit and the positive side of the power supply for the switching element drive circuit connected to the negative side of the power supply. And a charge pump circuit consisting of a diode connected as a cathode,
A motor control device in which one end of a dynamic brake circuit is connected to the negative side of a DC power source and is configured by a relay for the purpose of short-circuiting three wires connected to the output side of an inverter circuit via a resistor or directly. 2. A total of 6 switching elements, 3 sets of 2 switching elements connected in series between the + side and − side of the DC power source, and 6 rectifying elements connected in antiparallel thereto. , In an inverter circuit composed of a drive circuit for these switching elements, a capacitor used as a power supply for the drive circuit for the switching elements connected to the + side of the DC power supply, and a + side of this capacitor and a + side of the DC power supply. With a diode connected between the two as a cathode, a charge pump circuit composed of a resistor connected in series with this diode, and a relay for the purpose of short-circuiting the three wires connected to the output side of the inverter circuit directly or via a resistor. A motor control device in which one end of a dynamic brake circuit that is configured is connected to the negative side of a DC power supply. 3. A relay that short-circuits one or two wires connected to the output side of the inverter circuit with a resistor or directly to the negative side of the DC power supply.
Alternatively, the electric motor control device according to claim 2.