Sinusoidal current drive system and control method for single-winding brushless DC motor

Abstract

The invention relates to a motor driving system, in particular to a sine-wave current driving system of a single-winding brushless direct current motor and a control method thereof. The driving system and the control method calculate an input current phase angle instantaneous value and an input current instruction value according to the motor rotation frequency acquired by a position sensor, further sequentially obtain a circuit control voltage item, an instantaneous sensing voltage value and an output voltage instruction value, finally obtain the output duty ratio alpha so as to generate a PWM wave signal, transmits the signal to a full-bridge power inverter circuit so as to control a high-power switch device and accordingly achieves driving control of the single-winding brushless direct current motor. The driving control of the single-winding brushless direct current motor is performed by adopting the driving system and the control method, the motor is easy to start, the manufacture cost is low, vibration and noise are small during motor running, and an application range is wide.

Description

technical field [0001] The invention relates to a motor drive system, in particular to a sine wave current drive system of a single-winding DC brushless motor and a control method thereof. Background technique [0002] Brushless DC motor, also known as permanent magnet synchronous motor, has been widely used for its advantages of high efficiency, energy saving, quietness and small size. Compared with the traditional asynchronous motor, the magnetic steel embedded in the rotor provides a magnetic field, which greatly reduces the excitation current of the motor or even eliminates the excitation current, which greatly improves the efficiency of the motor body. [0003] At present, most brushless DC motors are composed of three-phase windings and driven by three-phase variable frequency drive devices. In order to reduce the cost, a single-winding brushless DC motor was proposed and practically verified. Since the stator of a single-winding brushless DC motor has only one phase...

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Problems solved by technology

[0007] 1. Since there is only one set of windings in a single-winding brushless DC motor, there is a torque dead zone where the electromagnetic torque tends to zero as the initial angle of the motor rotor stops, and it is necessary to adjust the positions of Hall and other positions during design The position of the sensor makes it difficult to control the motor when starting;

[0008] 2. The single-winding brushless DC motor must adopt a special structural design such as air gap and cogging to ensure the normal start of the motor. Its structure is complex and its manufacturing cost is relatively high;

[0009] 3. The magnetic field generated by the phase current of the motor and the magnetic field of the permanent magnet of the rotor synthesize the rotating magnetic field of the single-winding motor, and the phase current of the motor generated by the stator square wave voltage of equal duty cycle pulse width modulation (PWM) must not be sinusoidal waves, so that the rotating magnetic field of the motor contains a large number of high-order harmonic components, which in turn causes the electromagnetic torque of the motor to contain large pulsating components, making the vibration and noise of the single-winding brushless DC motor far more than that of the three-winding DC brushless motor. The brush motor is large;

[0010] 4. The electromagnetic torque of the motor with equal duty cycle pulse width modulation (PWM) is unidirectional when starting, that is, the rotation direction of the single-winding brushless DC motor can only be unidirectional when starting, which limits its application range. big limit

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