Method and system for controlling sensorless motor

Abstract

The invention discloses a method and system for controlling a sensorless motor. The method comprises the following steps: receiving current signals fed back by three phase windings of the motor respectively and controlling currents flowing through existing two phase conductive windings respectively to be equal; acquiring and calculating phase voltages, winding currents and winding resistance values of the three phase windings respectively to obtain a counter electromotive force approximate value of each phase winding respectively based on the phase voltages, the winding currents and the winding resistance values of the three phase windings; and judging whether the counter electromotive force approximate values of the three phase windings meet reversing trigger conditions or not respectively and controlling the corresponding windings to reverse when the counter electromotive force approximate values meet the reversing trigger conditions. Compared with the prior art, the method and system of the invention can be utilized to avoid using a ZCP (zero crossing point) signal conditioning circuit and reduce the control cost of the motor, and is simple in implementation way and high in reliability.

Description

technical field [0001] The invention belongs to the technical field of motor control, and in particular relates to a sensorless motor control method and system. Background technique [0002] The sensorless permanent magnet motor control method provided by the prior art is to control the three-phase permanent magnet synchronous motor as a three-phase brushless DC motor, referring to the 120-degree electrical angle of each phase winding in the brushless DC motor control. At the same time, the characteristics of the sine wave back EMF of the permanent magnet synchronous motor are comprehensively considered and the commutation method is reasonably selected. [0003] figure 1 The commutation waveform of the sensorless permanent magnet motor control method provided by the prior art is shown. Among them, Eu, Ev, and Ew are the three opposite potential waveforms of the motor, and Iu, Iv, and Iw are the currents flowing through the three-phase windings of the motor. The three-phas...

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Problems solved by technology

[0005] The purpose of the embodiments of the present invention is to provide a sensorless motor control method to solve the problem that the sensorless permanent magnet motor control method provided by the prior art needs to use a special zero-crossing point signal conditioning circuit to detect the counter electromotive force zero-crossing point information, and then Reversing with a delay of 30 degrees, the problem of complex design and high cost

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