Drive circuit for single-phase direct-current brushless sensorless motor

Abstract

The invention discloses a drive circuit for a single-phase direct-current brushless sensorless motor, and the drive circuit comprises a main drive circuit which comprises a single-chip microcomputer U2, field-effect transistors Q2-Q5, and a resistor R6 which is used for collecting a current value in a stator coil (113) in a rotating process of a rotor (2). According to the drive circuit provided by the invention, the current value in the current coil is obtained through the current sampling resistor R6 single-chip microcomputer, the current has a function relationship with the position and therotating speed of the brushless motor rotor, and the current rotor position can be calculated through the current. The motor adopts a position-sensorless mode, the work of a driving circuit is not influenced by motor vibration and temperature rise, and the reliability of the motor is improved.

Description

technical field [0001] The invention relates to the field of electronic circuits, in particular to a driving circuit for a single-phase DC brushless motor without a position sensor. Background technique [0002] Single-phase DC brushless motor is driven by only a single phase current in the excitation coil, and the rotor part is composed of permanent magnets or excitation coils with paired magnetic poles. The motor back EMF is a single phase AC voltage. The drive current commutation is completed by an external circuit, and the commutation time point is provided by an external Hall position sensor. [0003] Single-phase DC brushless motor is driven by only a single phase current in the excitation coil, and the rotor part is composed of permanent magnets or excitation coils with paired magnetic poles. The motor back EMF is a single phase AC voltage. The drive current commutation is completed by an external circuit, and the commutation time point is provided by an external H...

AI Technical Summary

Problems solved by technology

[0005] 1) The current motor uses a Hall sensor switch to generate a signal at the moment when the rotor magnetic pole is switched, so as to know the current position of the rotor. The conventional Hall sensor switch can only generate a signal at the moment when the rotor magnetic pole is switched. During the rotor transfer process The current position of the rotor cannot be known, so it can only be driven by a square wave, the driving efficiency is low, the torque fluctuation is large, and the electromagnetic noise is large during operation;

[0006] 2) Due to the use of Hall sensors for position sensing, the drive circuit that provides the drive current is powered by a single-cell lithium battery and needs a booster circuit to reduce the drive current, resulting in a complex drive circuit and many power devices in series in the coil drive current path. Low circuit efficiency, high cost, and reduced reliability

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