JP2817482B2 - DC motor drive circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a DC motor,
The present invention relates to a drive circuit for a brushless transistor motor that has been widely used recently.

[0002]

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

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 therein. 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, and the like. And a rotation signal terminal (FB) for outputting a motor rotation number signal detected by the motor. 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 produces a control power supply for the control circuit 2. The chopper circuit 7 includes a transistor 8, a fast recovery diode 9, a coil 10, and an electrolytic capacitor 11 for high ripple. The chopper circuit 7 changes the voltage of the power supply terminal of the DC motor 1 with a high-frequency signal applied to the base of the transistor 8. The number of rotations is controlled. Generally, a method is used in which a rotation signal (FB) of the DC motor 1 having the above-described configuration is input to a microcomputer (not shown), and thereby a feedback is added to a base signal of the transistor 8.

[0004]

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

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a low-cost DC motor drive circuit having a very simple circuit configuration, a small mounting space, and a principle capable of suppressing generated noise. The purpose is.

[0006]

According to the present invention, there is provided a bridge rectifier for full-wave rectifying a commercial power supply, a DC motor connected between DC terminals of the bridge rectifier, and an AC power supply for the bridge rectifier. A bidirectional thyristor connected to a terminal; and a DC low-voltage power supply for driving and controlling a control circuit of the DC motor.
As a power supply, the voltage that has been full-wave rectified by the bridge rectifier is directly
And the control circuit is configured to apply the D
Set a rotation signal terminal to detect and output the rotation speed of the C motor.
The bidirectional thyristor is output by the output of the rotation signal terminal.
Applied to the DC motor by phase control
Change the phase angle of full-wave rectified voltage to control rotation speed
I have to.

[0007]

According to the present invention, a full-wave rectified commercial power supply is applied to a DC motor, and the energization phase angle is controlled by a microcomputer or the like via a bidirectional thyristor by the above-mentioned means for solving the problem. Can be controlled.

[0008]

An embodiment of the present invention will be described below with reference to FIG. The same components as those in the conventional example are denoted by the same reference numerals, and description thereof is omitted.

As shown in FIG.
Consists of a power transformer 13, a bridge rectifier 14, an electrolytic capacitor 15 and a 5V regulator IC 16,
As a control power supply for the control circuit 2 built in the DC motor 1
Supply. The bridge rectifier 17 performs full-wave rectification on the commercial power supply 18, connects a bidirectional thyristor 19 to an AC terminal on the input side of the bridge rectifier 17, and connects a DC between the DC terminals on the output side. Power supply terminal of motor 1 (VM, GND)
To connect the commercial power supply 18 to the full-wave rectified voltage.
The voltage is applied as it is.

Next, the operation of the above configuration will be described.
By changing the pulse signal in synchronization with the energizing phase angle, D
The phase angle of the full-wave rectified voltage applied to the power supply terminal of the C motor 1 changes, and the rotation speed of the DC motor 1 changes. This is shown in FIGS. 2 (a) and 2 (b). 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 arbitrarily controlled. In this embodiment, the gate signal of the bidirectional thyristor 19 is formed by a microcomputer (not shown). Also, D
To a rotation signal terminal (FB) of the C motor 1, a rotation signal synchronization pulse of the DC motor 1 detected by a hall element (not shown) provided in the built-in control circuit 2 is output. This signal is input to a microcomputer and compared with the number of rotations to be controlled.
By adding feedback to the gate signal of No. 9, more precise control of the number of rotations becomes possible.

Note that a control power supply 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 relatively small capacities. Although some electrical noise is generated by the phase angle control of the bidirectional thyristor 19, measures to reduce the noise are simple compared to the noise generated from the high-frequency chopper circuit as shown in the conventional example. Can be dealt with.

[0012]

As is apparent from the above embodiments, according to the present invention, a commercial power supply is directly used as a drive power supply for the DC motor, so that a large-capacity power supply transformer or switching power supply as in the prior art is not required. In addition, 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, the heat radiation design can be simplified and the reliability of the circuit itself can be improved. Further, the rotation speed of the DC motor can be controlled by controlling the phase angle by the bidirectional thyristor, so that a high-frequency chopper circuit as in the related art is not required, and electric noise generated from the circuit can be easily reduced.

[Brief description of the drawings]

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

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

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

[Description of Signs] 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 Kazuma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-4-208087 (JP, A) Field (Int.Cl. ⁶ , DB name) H02P 6/08 H02M 7/06

Claims (1)

(57) [Claims] 1. A bridge rectifier for full-wave rectification of a commercial power supply, 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 A DC low-voltage power supply for driving and controlling the control circuit of the brushless transistor motor.
A voltage that is full-wave rectified by the bridge rectifier as a power supply for operation
And a rotation signal terminal for detecting and outputting the number of rotations of the brushless transistor motor in the control circuit, and controlling the phase of the bidirectional thyristor by the output of the rotation signal terminal. Full- wave rectified voltage applied to brushless transistor motor
DC motor drive circuit that controls the rotation speed by changing the phase angle of the motor.