Virtual inductance self-correcting permanent magnet motor current ripple spread spectrum control method and system

Abstract

The invention discloses a virtual inductance self-correcting permanent magnet motor current ripple spread spectrum control method and system, and belongs to the technical field of motors. According to a virtual inductance parameter set value, a three-phase current ripple peak value is used as a control object, a three-phase current ripple spread spectrum control module is used for updating the switching frequency of a next switching period and calculating a three-phase current ripple characteristic inflection point predicted value; sampling to obtain a three-phase current ripple characteristic inflection point sampling value; inputting the sampling value and the predicted value of the characteristic inflection point of the three-phase ripple current into a virtual inductance self-correction module, and obtaining a virtual inductance correction value through decoupling function calculation and proportional-integral control; and according to the virtual inductance correction value, a virtual inductance parameter set value is updated, so that high-accuracy control of the three-phase current ripple peak value is realized. The method comprehensively considers the self-inductance and mutual-inductance parameters of the motor, reduces the influence of the inductance change on the current ripple prediction precision in the operation process of the motor, improves the control accuracy of the system, and achieves a better current ripple control effect.

Description

technical field [0001] The invention belongs to the technical field of motors, and more particularly, relates to a method and a system for current ripple spread spectrum control of a permanent magnet motor with virtual inductance self-correction. Background technique [0002] Among many types of motors, permanent magnet synchronous motors are widely used in electric vehicles, fans, machine tools, etc. due to their high efficiency, high power density, simplicity and reliability. In recent years, due to the emergence and development of new technologies, new processes and new devices, the performance of permanent magnet synchronous motors has been further improved, and its application areas have been continuously expanded. [0003] In order to reduce the operating loss of the permanent magnet motor and improve the safety and stability of the entire electromagnetic system, the state has current ripple control requirements for the control system. In order to meet this requiremen...

AI Technical Summary

Problems solved by technology

In order to meet this requirement, the traditional system adopts the method of increasing the switching frequency to reduce the current ripple, but at some moments the current ripple is far lower than the application demand, resulting in additional switching loss; at the same time, a single switching frequency will lead to a decrease in the switching frequency. Increased EMI

According to the existing scheme of adjusting the switching frequency by calculating the current ripple through given parameters, although the parameters can achieve a better control effect when the parameters are accurate, in most cases, due to bus voltage fluctuations, inductance changes with temperature or The magnetic circuit is saturated due to the current and internal power factor angle changes caused by loading and unloading, and the actual system parameters will deviate from the set value

At this time, it is difficult to achieve the desired ripple control effect by using this control scheme, and its ripple control stability cannot be guaranteed.

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