Control method for correcting phase of brushless DC motor without position sensor

Abstract

The invention discloses a method for correcting and controlling a phase position of a brushless DC motor of a non-position sensor. The method is characterized by comprising the following steps: (1) at least one sampling point is arranged at intervals between the starting rotating speed and the rated rotating speed of the motor, the relation curve of the speed and the phase position delay is mapped by recording the value of the electrical angle corresponding to the phase position delay; (2) the motor control program is written, the phase position delay compensating program is added into the signal process of the acquired BEMF so that the phase is switched at the accurate phase-changing point; (3) the motor is started in the way of positioning first and then accelerating slowly; and (4) when the motor reaches the starting rotating speed, the BEMF zero-crossing signal is acquired, and the calculation compensation is performed by the phase position compensating sub program written in the motor control program and the phase changing control sub program. The method has the advantages of simplicity and flexibility, and particularly can correct the phase position lagging caused by the position detection circuit in real time. The method can be widely applied to the phase position correction control of the brushless DC motor of various non-position sensors.

Description

technical field [0001] The invention relates to motor control, in particular to a phase correction control method of a brushless direct current motor without a position sensor. Background technique [0002] An existing brushless DC motor (BLDCM for short) usually has one or more rotor position sensors during operation, and the switching on and off of the inverter power device depends on the rotor position of the motor detected by the position sensor in real time. Due to factors such as cost, reliability, and mechanical assembly, especially when the rotor is submerged in liquid, it is very inconvenient to install the rotor position sensor, and the stability and reliability are poor. [0003] For this reason, a variety of BLDCM sensorless control methods have been introduced in recent years, among which the Back Electromotive Force (BEMF) method is currently the most commonly used sensorless control method for detecting rotor position signals. When the motor rotates, the phas...

AI Technical Summary

Problems solved by technology

The filter circuit will be used in the circuit design to ensure that the signal is stable, so as to avoid false interference signals. However, after the filter circuit is used, different frequencies corresponding to the rotational speed will produce different electrical angle phase shifts, that is, phase delays, resulting in the BEMF zero-crossing signal. Accurate and delayed commutation will make the motor run unstable, even out of step or stop the serious consequences

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