A method and system for controlling a permanent magnet synchronous motor

Abstract

The invention discloses a permanent magnet synchronous motor control method and system. Compared with the traditional single-vector MPC, the common-mode voltage is suppressed, the current ripple is reduced, and the steady-state performance is improved. Compared with the existing two-vector MPC, The complexity of the algorithm is reduced, and the amount of calculation is reduced. The method includes: collecting the mechanical and electrical parameters of the permanent magnet synchronous motor at the current moment; calculating the rotating reference voltage vector of the synchronous rotating coordinate system, and converting it into a stationary reference voltage vector of the stationary coordinate system; determining the position of the stationary reference voltage vector at the base voltage vector The sector of the plane; select 2 effective vectors from the plane vector according to the sector, and synthesize to obtain the composite vector; calculate the first distance and the second distance from the static reference voltage vector to the zero vector and the side where the composite vector is located; according to the first distance and the second distance, select an alternative vector; calculate the action time of the alternative vector, determine the action time of all basic voltage vectors, and control the permanent magnet synchronous motor.

Description

technical field [0001] The invention relates to the field of motors, in particular to a control method and system for a permanent magnet synchronous motor. Background technique [0002] Permanent-magnet synchronous motor (Permanent-Magnet Synchronous Motor, PMSM) has been widely used in electric vehicles and other fields due to its advantages of high power density, low cost, high efficiency, and good reliability. In the PMSM control system, the common mode voltage will produce overvoltage stress on the insulation between the motor winding and the motor bearing, and the magnitude of the common mode voltage is an important indicator to measure the intensity of electromagnetic interference. [0003] Model predictive control (Model Predictive Control, MPC) is used for common-mode voltage suppression with its many advantages. Among the eight basic voltage vectors provided by the two-level voltage source inverter, the common-mode voltage amplitude generated by the zero vector is ...

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Problems solved by technology

[0004] Although the common-mode voltage suppression method of the traditional single-vector MPC does not use a zero vector in each control cycle, which significantly suppresses the common-mode voltage, but because no zero vector is used and there is only one vector in one control cycle, the current ripple is large and the steady-state performance is poor. ; In the existing two-vector MPC, some algorithms first select the first effective vector through the cost function, and the second vector is selected from the vectors adjacent to the first effective vector, and the combined action time of the two sets of vectors is calculated and then substituted into the cost function Optimization, this type of method requires multiple calculations to optimize, the algorithm is complex, and the amount of calculation is large

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