Control method and system of permanent magnet synchronous motor

Abstract

The invention discloses a control method and system of a permanent magnet synchronous motor. The control method comprises the steps that stator flux linkage of the permanent magnet synchronous motor and stator flux linkage deviation are worked out by the adoption of a voltage model and a current model; stator flux linkage of the synchronous motor and rotor flux linkage of the synchronous motor under a dp coordinate system are worked out by the utilization of a conversion matrix between a two-phase static coordinate system and a two-phase synchronous rotating coordinate system; finally, the rotor position angle and the rotor angular speed of the permanent synchronous motor are worked out through the closed loop phase lock technology of rotor q-axis flux linkage. The control method and system of the permanent magnet synchronous motor have the advantages that on the basis of a non-sensor estimation method of a flux linkage closed loop phase-locked loop of the rotor flux linkage of the permanent magnet synchronous motor and by the adoption of the technology of conducting compensation on the stator flux linkage deviation through the voltage model and the current model, the accuracy of the estimation algorithm is improved and effective control over the permanent magnet synchronous motor in the full-speed range can be realized.

Description

Technical field [0001] The invention relates to the field of control of synchronous motors, and more specifically, to a method and system for controlling permanent magnet synchronous motors applied to full-power wind power converters. Background technique [0002] Direct-drive wind power generation system is a new type of wind power generation system that uses a wind turbine to directly drive a multi-pole low-speed permanent magnet synchronous motor (PMSM) to generate electricity, and then combines the electrical energy converted by a full-power converter into the grid. Compared with the double-fed induction motor (DFIG) wind power system, the direct-drive wind power system eliminates the need for traditional gearboxes, has high system efficiency and operational reliability, and has the advantages of easier implementation of the low-voltage ride-through function, so the direct-drive wind power system It has a wide range of application prospects. [0003] The key equipment in the f...

AI Technical Summary

Problems solved by technology

[0004] Existing methods to obtain reliable rotor information include (1) sensor technology, using mechanical devices such as photoelectric code discs and resolvers to measure, which will bring problems such as increased cost, difficult installation and maintenance, and external interference; (2) back electromotive force The method is a sensorless method for permanent magnet synchronous motors that is widely used in existing wind power converters.

However, due to the small back electromotive force of the motor at low speed and the influence of external interference factors, it is difficult to accurately detect the back electromotive force

Therefore, this method cannot control the stable operation of the motor at low speed

And some other sensorless methods for estimating the rotor position angle are not only complicated in processing method and implementation process, but the effectiveness of its practical application needs to be verified, and its calculation accuracy cannot be guaranteed

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