Control circuit and starting method for single-phase direct current brushless electric motor non-position sensor

Abstract

The invention relates to the field of direct current brushless electric motor control and specifically discloses a control circuit and a starting method for a single-phase DC brushless motor non-position sensor. The control circuit comprises an MCU control chip, a power supply unit and an inverter circuit, wherein the power supply unit is connected to the inverter circuit; the inverter circuit isconnected with a half bridge driving circuit, a counter electromotive force sampling unit, a current sampling circuit and a brushless motor; the half bridge driving circuit, the counter electromotiveforce sampling unit and the power supply unit are connected to the MCU control chip; the current sampling circuit is connected with a starting current feedback circuit, the starting current feedback circuit is connected to the brushless motor and the MCU control chip, and the MCU control chip is connected to the power supply unit. The control circuit and the starting method disclosed in the invention can help effectively prevent a problem of boot failure caused by fixed excitation time adopted in a conventional method, the position of a rotor can be confirmed during excitation processes, excitation directions can be changed at suitable positions, and rates of boot success can be improved.

Description

technical field [0001] The invention relates to the field of DC brushless motor control, in particular to a control circuit and a starting method for a single-phase DC brushless motor without a position sensor. Background technique [0002] With the increasing development of the motor industry, brushless DC motors have been widely used in many fields. It has the advantages of good speed regulation performance, small size, long life and high efficiency. Since the pole pairs of the stator and the rotor of the single-phase brushless DC motor correspond to each other, there is a problem of difficulty in starting. Therefore, the stator cogging will be asymmetrically processed in the structure, so that it will produce an asymmetrical air-gap reluctance, that is, in In the non-energized state, the centerline of the rotor magnetic circuit deviates from the stator centerline by a certain angle, so that the electromagnetic torque can overcome the cogging torque and make the motor star...

AI Technical Summary

Problems solved by technology

[0003] In many applications of single-phase brushless DC motors, Hall position sensors are usually added to detect the rotor position. However, due to the existence of position sensors, the operation of the motor is limited by the position sensors. The installation position of the position sensors will affect the motor operating parameters, such as Current, speed, output power, efficiency, etc. At the same time, if the installation position deviates greatly, it will cause the motor to fail to start, high-frequency vibration, and even damage the motor or control system

[0004] The position sensorless technology used in the prior art uses push to set the length of time, and then performs commutation processing, but this technology still cannot solve the problem of starting the unidirectional brushless DC motor without a position sensor, and push failure will occur , poor adaptability and other issues

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