Control method and system of permanent magnet synchronous motor

Abstract

The embodiment of the invention provides a control method and system of a permanent magnet synchronous motor, and belongs to the control field of the permanent magnet synchronous motor. The control method of the permanent magnet synchronous motor comprises the following steps: determining an assumed angle of a rotor of the permanent magnet synchronous motor about an assumed rotational coordinate system at the first time of the starting stage, wherein the constancyof the specific value of the voltage vector amplitude, which is corresponding to the single current loop input,relative to the rotation speed of the rotor is maintained at the starting stage; acquiring the actual angle of the rotor about the actual rotational coordinate system at the first time; computing the first angle difference value between the assumed angle and the actual angle, and judging whether the first angle difference value is in the angle difference threshold range; and judging whether the first duration time of the angle difference value in the angle difference threshold range is greater than the time threshold; if the first duration time is greater than the time threshold, switching the permanent synchronous motor to a closed loop control state. Therefore, the closed loop switching stability of the motor is improved.

Description

technical field [0001] The invention relates to the field of permanent magnet synchronous motor control, in particular to a permanent magnet synchronous motor control method and system. Background technique [0002] With the rapid development of motor technology, the motors of some air-conditioning cooling fans and compressors are permanent magnet synchronous motors without position sensors. The parameter estimates the rotor position and starts the motor after the rotor position is estimated. [0003] In related technologies, it is common to use the back EMF model to drive the compressor of the air conditioner or refrigerator and use it to estimate the position angle and speed of the rotor. This implementation method has been widely popularized due to its simple operation. The way of single current start: the frequency of the compressor is pulled up to a certain frequency in the speed open loop mode, and then it is directly switched to the closed loop. [0004] The invento...

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Problems solved by technology

[0005] The purpose of the embodiments of the present invention is to provide a control method and system for a permanent magnet synchronous motor, which is used to solve the large problem caused by the direct switching of the permanent magnet synchronous motor from the open-loop starting circuit to the closed-loop working circuit in the prior art. Technical issues with switching current and failure of the motor to start

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