Control circuit and starting method of single-phase DC brushless motor without position sensor

Abstract

The invention relates to the field of DC brushless motor control, and specifically discloses a control circuit and a starting method for a single-phase DC brushless motor without a position sensor, including an MCU control chip, a power supply unit and an inverter circuit, and the power supply unit is connected to an inverter circuit, the inverter circuit is connected with a half-bridge drive circuit, a back electromotive force sampling unit, a current sampling circuit and a brushless motor, the half-bridge drive circuit, a back electromotive force sampling unit and a power supply unit are connected to an MCU control chip, and the current sampling The circuit is connected with a start-up current feedback circuit, the start-up current feedback circuit is connected with the brushless motor and the MCU control chip, and the MCU control chip is connected with the power supply unit, the present invention effectively avoids the problem of start-up failure caused by using a fixed excitation time in conventional methods, and can Confirm the position of the rotor during the excitation process, so that the excitation direction can be changed at the appropriate position, and the success rate of starting 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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