Permanent-magnet synchronous motor start-up smooth switching method

Abstract

The invention provides a permanent-magnet synchronous motor start-up smooth switching method. The method includes the following steps: presupposing that given torque current is identically 1.5 times that of rated current of a permanent magnet synchronous motor; presupposing that a rotor position angle is increased progressively at a T-squared growth rate, and enabling the permanent magnet synchronous motor to rotate at a constant accelerated speed; when the speed of the permanent magnet synchronous motor reaches 30% of a rated rotation speed, beginning to carry out switching transition, enabling a rotor position angle used for PARK transformation and reverse transformation to gradually approach an actual rotor position angle acquired by a position and speed estimator, and meanwhile, enabling the presupposed torque current to gradually approach torque current calculated by adopting the actual rotor position angle; and when time for switching transition arrives, switching closed-loop control states of the speed, the position and the current. The method can achieve the purposes that the rotor position and phase current are undistorted and the rotation speed does not oscillate in start-up switching of the permanent-magnet synchronous motor only by one-time parameter setting under any load.

Description

technical field

[0001] The invention relates to a permanent magnet synchronous motor, in particular to a position sensorless magnetic field orientation control permanent magnet synchronous motor for loads such as fans, pumps and compressors. A method for smooth switching of current three closed loops. Background technique

[0002] Field Oriented Control is currently recognized as the most advanced motor control theory in the industry, which enables permanent magnet synchronous motors to operate at any speed with higher efficiency, better dynamic response and smaller torque fluctuations. At present, the field-oriented control system of permanent magnet synchronous motors generally adopts the three closed-loop control methods of position, speed and current. In order to calculate the torque current component and flux current component required for the operation of permanent magnet synchronous motors, it is necessary to obtain reliable rotor information in real time. . For hig...

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