Sensorless brushless DC motor commutation position correction system and method

Abstract

The invention discloses a sensorless brushless DC motor commutation position correction system and method. The system comprises a DC power supply, a three-phase full-bridge inverter, a brushless DC motor, a terminal voltage step-down and filtering circuit, a counter potential zero crossing detection circuit, a DC bus and a b-phase terminal voltage detection circuit, a digital signal processor anda PWM signal driving circuit. The counter potential zero crossing offset caused by filtering and the commutation position offset caused by the hardware circuit device delay and the software calculation delay can be simultaneously compensated by detecting the DC bus voltage and the terminal voltage. Compared with the existing sensorless brushless DC motor commutation position correction system, therequired detection amount is low, the calculation workload is low, the rotor commutation position offset can be quickly and accurately corrected, the accurate rotor commutation position can be obtained and the control and operation performance of the brushless DC motor can be enhanced. The sensorless brushless DC motor commutation position correction system has high universality and is suitable for the sensorless brushless DC motor control system using multiple control strategies.

Description

technical field [0001] The invention relates to the technical field of motor control, in particular to a commutation position correction system and method for a brushless DC motor without a position sensor. [0002] Background technique: [0003] Brushless DC motors are widely used in household appliances, instrumentation, chemical textiles, office automation equipment, and medical equipment because of their advantages such as simple structure, stable operation, high efficiency, and convenient maintenance. The brushless DC motor needs to provide the commutation information of the three-phase winding according to the rotor position, but the installation of the position sensor not only increases the volume and cost of the motor, but also increases the number of signal lines, which will reduce the reliability of the motor operation. In order to make the motor run stably in a complicated working environment, the position sensorless control technology of brushless DC motor has bee...

AI Technical Summary

Problems solved by technology

The most commonly used position detection method for sensorless brushless DC motors is the back-emf zero-crossing method, which determines the commutation position of the rotor according to the back-emf zero-crossing point, but this method will be affected by the phase caused by the filter circuit in the back-emf zero-crossing detection circuit The influence of phase shift caused by factors such as offset, detection circuit device delay, and control chip software calculation delay makes the commutation position detection inaccurate, resulting in deviation of the commutation position, and deterioration of motor control and operation performance. In severe cases, even May cause the motor to lose step

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