JPH06141589A - Driving system for two-phase induction motor - Google Patents

Abstract

PURPOSE:To provide a driving system for two-phase induction motors the efficiency of which does not drop even when its load fluctuates. CONSTITUTION:The system uses a three-phase transistor voltage type inverter circuit 1 and the six transistors of an inverter circuit 3 are turned on and turned off so that the electric current flowing through the stator winding of a two- phase induction motor 2 can be repeatedly made to flow in the normal direction through the first-phase winding, in the normal direction through the second-phase winding, in the reverse direction through the first-phase winding, and in the reverse direction through the second-phase winding in the described order by respectively connecting the three-phase output terminals of the circuit 1 to one ends of the first- and second-phase windings and the junction of the first- and second-phase windings.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive system for a two-phase induction motor used in a fan motor or the like.

[0002]

2. Description of the Related Art Conventionally, when performing inverter control of a fan motor or the like, a three-phase voltage type inverter circuit has been used in a three-phase induction motor, and it exhibits stable control characteristics. The three-phase winding has a complicated structure and becomes costly, and in a commonly used fan motor or the like, the number of two-phase induction motors having a simple winding is increasing. When controlling a two-phase induction motor by an inverter, a method of using a single-phase voltage type inverter circuit and using a capacitor for phase advance as shown in FIG. 2 (a) is used. And the load changes, the phase angle changes and the efficiency changes,
I couldn't always drive at the best efficiency. Also,
As shown in FIG. 2B, a single-phase voltage type inverter circuit
When it is used individually, it can be operated with stable efficiency, but the cost of the inverter increases and it cannot be said to be an effective drive system.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and an economical and efficient driving method for a two-phase induction motor is realized by using a three-phase voltage type inverter circuit. It is intended to be provided.

[0004]

In order to achieve the above object, a three-phase transistor voltage type inverter circuit is used as an inverter circuit for controlling a two-phase induction motor, and three outputs of the same three-phase transistor voltage type inverter circuit are used. The terminal is connected to one end of the first phase winding and one end of the second phase winding of the two-phase induction motor and the other end joint of the first phase winding and the second phase winding of the two-phase induction motor, and the two-phase induction motor is controlled by the control circuit. The transistors of the three-phase transistor voltage type inverter circuit are controlled to be turned on and off so that the current flowing through the first phase winding and the second phase winding is sequentially switched to the forward direction or the reverse direction to generate the rotating magnetic field.

[0005]

According to the above structure, the three-phase transistor voltage type inverter circuit is connected to the two-phase induction motor, the current flowing through the stator of the two-phase induction motor is sequentially switched by the control circuit, and the cycle is repeated at a constant cycle. It is possible to form a rotating magnetic field and efficiently drive the two-phase induction motor.

[0006]

Embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a wiring diagram showing details of the present invention. A three-phase transistor voltage type inverter circuit 1 in which three pairs of two transistors connected in series are connected in parallel, and a DC voltage E applied to its input terminal are shown. , A stator winding of the two-phase induction motor 2 including a main winding M and an auxiliary winding A, and an inverter control circuit 3 for controlling ON / OFF of six transistors. Three output terminals drawn out from the middle of the two transistors are connected to one end of the main winding M and the auxiliary winding A of the two-phase induction motor 2 and a joint portion between the main winding M and the auxiliary winding A. Then, a PWM pulse signal is sent from the inverter control circuit 3 to the bases of the respective transistors, and the transistors are sequentially turned on / off to supply a square wave voltage to the two-phase induction motor 2. In this state, as an example, the inverter control circuit 3 (1) turns on the transistor Tr 3 and turns on the transistor Tr 5
ON (main winding M in positive direction) (2) Transistor Tr 3 is turned ON, transistor Tr 4
ON (main winding M and auxiliary winding A in the positive direction) (3) Transistor Tr 2 is turned on, transistor Tr 4
ON (Auxiliary winding A in the forward direction) (4) Transistor Tr 2 is turned ON, transistor Tr 6
(5) Transistor Tr 1 is turned on and transistor Tr 6 is turned on.
(6) Transistor Tr 1 is turned on and transistor Tr 5 is turned on (reverse direction of auxiliary winding A and main winding M)
Is turned on and the auxiliary winding A is switched in the opposite direction to switch the transistor to generate a rotating magnetic field and drive the two-phase induction motor 2. Good PWM control can be performed by increasing the carrier frequency of the inverter control circuit 3 from several KHz to several tens KHz.

[0007]

As described above, in the present invention, by controlling the inverter of the two-phase induction motor by the three-phase transistor voltage type inverter circuit, it is possible to efficiently control without using the phase advancing capacitor. Further, the cost of the inverter unit can be reduced as compared with the case of using two sets of single-phase voltage type inverters, and a simpler two-phase induction motor can be used than a three-phase induction motor having a complicated stator winding. .

[Brief description of drawings]

FIG. 1 is a wiring diagram showing details of inverter control of a two-phase induction motor of the present invention.

FIG. 2 is a wiring diagram showing details of conventional inverter control of a two-phase induction motor.

[Explanation of symbols]

 1 3 Phase Transistor Voltage Type Inverter Circuit 2 2 Phase Induction Motor 3 Inverter Control Circuit 4 2 Phase Transistor Voltage Type Inverter Circuit 5 Phase Advance Capacitor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuji Kawai 1116 Suenaga, Takatsu-ku, Kawasaki City, Fujitsu General Ltd. (72) Inventor Koji Mori 1116 Suenaga, Takatsu-ku, Kawasaki City, Fujitsu General (72) Inventor Yuji Soma 1116 Suenaga, Takatsu-ku, Kawasaki-shi In Fujitsu General Limited

Claims (1)

[Claims] 1. A three-phase transistor voltage type inverter circuit is used as an inverter circuit for controlling a two-phase induction motor, and three output terminals of the three-phase transistor voltage type inverter circuit are connected to a first-phase winding of the two-phase induction motor. One end of the second phase winding and one end of the first phase winding and the other end of the second phase winding are connected to each other by the control circuit, and the first phase winding and the second phase winding of the two-phase induction motor are connected. A method for driving a two-phase induction motor characterized in that the transistors of a three-phase transistor voltage type inverter circuit are controlled to be turned on and off so as to sequentially generate a rotating magnetic field by sequentially switching the current flowing in the direction of forward or reverse.