JPH05137378A - Driving circuit for dc motor - Google Patents

Abstract

PURPOSE:To provide a simple driving circuit for directly driving a brushless transistor motor by a bidirectional thyristor by full-wave rectification of a commercial power supply. CONSTITUTION:A brushless transistor motor 1 is connected between DC terminals of a bridge rectifier 17 for full-wave rectifying a commercial power supply 18, and a bidirectional thyristor 19 is connected to AC terminals. A rotation signal terminal FB for sensing the rotational speed of the motor 1 and outputting it is provided to a control circuit 2 of the motor 1 to be controlled to be driven by a DC low voltage power supply 12, the thyristor 19 is phase-controlled by the output of the terminal FB to control the rotational speed of the motor 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a DC motor,
The present invention relates to a drive circuit for a brushless transistor motor, which has become popular recently.

[0002]

2. Description of the Related Art As a drive circuit for a conventional brushless transistor motor (hereinafter referred to as a DC motor), a power transformer, a switching power supply, or the like is used to generate a necessary DC voltage, and this DC voltage is applied to the DC motor for control. The method is common.

FIG. 3 shows a conventional DC motor drive circuit, and its configuration will be described below. As shown in the figure, the DC motor 1 has a control circuit 2 built-in, and the control circuit 2 has a power supply terminal (VM, GND) for driving the motor, a control power supply terminal (VD) for the built-in transistor, a hall element, etc. A rotation signal terminal (FB) for outputting a rotation speed signal of the motor detected by. Power transformer 3,
The bridge rectifier 4 and the electrolytic capacitor 5 constitute a DC power supply required for the DC motor 1. The 5V regulator IC 6 creates a control power supply for the control circuit 2. The chopper circuit 7 is composed of a transistor 8, a fast recovery diode 9, a coil 10 and an electrolytic capacitor 11 for high ripple, and changes the voltage of the power supply terminal of the DC motor 1 with a high frequency signal given to the base of the transistor 8. The rotation speed is controlled. In general, a method is used in which the rotation signal (FB) of the DC motor 1 having the above-mentioned configuration is input to a microcomputer (not shown), and a feedback is added to the base signal of the transistor 8 by this.

[0004]

However, in the circuit configuration as described above, since the DC power supply corresponding to the capacity of the DC motor 1 is required as described above, the power supply transformer 3, the bridge rectifier 4, and the electrolytic capacitor 5 are high. The capacity is not only a problem in terms of mounting space and weight, but also uneconomical in terms of cost. Further, since a high-frequency current flows through the chopper circuit 7 that controls the rotation speed, there are many problems such as the need for a countermeasure circuit for reducing unnecessary radiation noise generated from the chopper circuit 7.

The present invention solves the above problems, and provides a DC motor drive circuit at a low cost, which has an extremely simple circuit structure, can reduce the mounting space, and can also suppress generated noise in principle. Has a purpose.

[0006]

In order to achieve the above object, the present invention provides a bridge rectifier for full-wave rectifying a commercial power source, a DC motor connected between the DC terminals of the bridge rectifier, and an AC of the bridge rectifier. A bidirectional thyristor connected to the terminal and a direct current low voltage power supply circuit for driving and controlling the control circuit of the DC motor, and the control circuit is provided with a rotation signal terminal for detecting and outputting the rotation speed of the DC motor, The problem solving means is that the bidirectional thyristor is phase-controlled by the output of the rotation signal terminal to control the rotation speed of the DC motor.

[0007]

The present invention applies the full-wave rectified commercial power source to the DC motor by the above means for solving the problem, and controls the energizing phase angle by a microcomputer or the like via a bidirectional thyristor to thereby rotate the DC motor. Can be controlled.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. The same components as those in the conventional example are designated by the same reference numerals and the description thereof will be omitted.

As shown in the figure, the DC low-voltage power supply circuit 12
Is composed of a power transformer 13, a bridge rectifier 14, an electrolytic capacitor 15 and a 5V regulator IC 16,
The control circuit 2 built in the DC motor 1 is drive-controlled. The bridge rectifier 17 performs full-wave rectification on the commercial power supply 18, and the AC terminal of the bridge rectifier 17 is connected to the bidirectional thyristor 1.
9, and the power supply terminals (VM, GND) of the DC motor 1 are connected between the DC terminals.

To explain the operation of the above structure, the phase angle of the voltage applied to the power supply terminal of the DC motor 1 is changed by changing the conduction phase angle applied to the gate terminal of the bidirectional thyristor 19. , The rotation speed of the DC motor 1 changes. This is shown in FIGS. 2 (a) to 2 (c). Therefore, by controlling the phase angle of the pulse signal applied to the gate terminal of the bidirectional thyristor 19,
The rotation speed of the DC motor 1 can be controlled arbitrarily.
In this embodiment, a gate signal of the bidirectional thyristor 19 is generated by a microcomputer (not shown). In addition, the rotation signal terminal (F
A rotation signal synchronizing pulse of the DC motor 1 detected by a Hall element or the like provided in the built-in control circuit 2 is output to B). By inputting this signal to the microcomputer and comparing it with the rotation speed to be controlled and adding feedback to the gate signal of the bidirectional thyristor 19, it is possible to control the rotation speed more precisely.

The control power source terminal (V
The control current required for D) is about 100 mA, so that the power transformer 13, the electrolytic capacitor 15 and the like can be configured with a relatively small capacity. Further, although some electric noise is generated by controlling the phase angle of the bidirectional thyristor 19, compared with the noise generated from the high frequency chopper circuit as shown in the conventional example, a measure for reducing the noise is simple. Can be dealt with.

[0012]

As is apparent from the above embodiments, according to the present invention, since the commercial power source is directly used as the drive power source of the DC motor, the power transformer and the switching power source having a large capacity as in the prior art are unnecessary. The mounting space can be reduced, the weight can be reduced and the cost can be reduced, and since heat-generating components such as a power transformer and a switching power supply are not required, heat dissipation design can be facilitated and reliability of the circuit itself can be improved. Furthermore, the number of rotations of the DC motor can be controlled by controlling the phase angle by the bidirectional thyristor, the conventional high frequency chopper circuit is not required, and the electric noise generated from the circuit can be easily reduced.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a DC motor drive circuit according to an embodiment of the present invention.

2A to 2C are timing charts of the same DC motor drive circuit.

FIG. 3 is a circuit diagram of a conventional DC motor drive circuit.

[Explanation of symbols]

 1 DC Motor (Brushless Transistor Motor) 2 Control Circuit 12 DC Low Voltage Power Supply Circuit 17 Bridge Rectifier 18 Commercial Power Supply 19 Bidirectional Thyristor FB Rotation Signal Terminal

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masaatsu Inoue 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] 1. A bridge rectifier for full-wave rectifying a commercial power source, a brushless transistor motor connected between DC terminals of the bridge rectifier, a bidirectional thyristor connected to an AC terminal of the bridge rectifier, and the brushless transistor motor. And a DC low-voltage power supply circuit for driving and controlling the control circuit, the control circuit is provided with a rotation signal terminal for detecting and outputting the rotation speed of the brushless transistor motor, and the bidirectional thyristor is provided by the output of the rotation signal terminal. A DC motor drive circuit for controlling the rotation speed of the brushless transistor motor by phase control.