Motor phase current reconstruction method based on symmetric pulse width modulation (PWM) carrier wave

Abstract

The invention aims at solving the problem that in the existing motors which operat at high speed and adopt a single-current sampling method to reconstruct phase current, and space vector pulse width modulation (SVPWM) can not finish phase current reconstruction in a non-observation area at the position of a sector boundary and providing a motor phase current reconstruction method based on symmetric pulse width modulation (PWM) carrier wave, wherein algorithm of the method is easy to achieve, and a control effect of the method is relatively better. The method decomposes a modulation vector into two non-zero basic space vectors adjacent to a non-zero basic space vector in a sector boundary area, and the single-current sampling method is adopted to reconstruct motor phase current in an acting process of the adjacent two non-zero basic vectors. The method enables the non-observation area in the sector boundary area to adopt a symmetrical PWM method to modulate, converts the non-observation area into an observation area, and can reconstruct the motor phase current in the non-observation area in single-current sampling method.

Description

technical field [0001] The invention relates to the technical field of motor phase current reconfiguration, in particular to a motor phase current reconfiguration method based on a symmetrical PWM carrier. [0002] Background technique [0003] In the AC motor control system, the phase current detection of the motor is a key link. The classic method is to use the current sensor to detect the phase current of the motor, that is, set 3 or at least 2 current sensors at the AC output end to provide the phase current feedback signal. Commonly used current sensors are Hall effect detectors, which are not only expensive but also bulky and difficult to integrate in power electronics. Therefore, in the case that the precision does not need to be too high and the cost needs to be reduced, a method of detecting the phase current of the motor by sampling the DC bus current is proposed. [0004] The phase current of the motor is detected by DC bus current sampling, which is often refe...

AI Technical Summary

Problems solved by technology

[0011] The purpose of the present invention is to solve the problem that the phase current cannot be reconstructed by SVPWM modulation in the non-observation area at the boundary of the sector by means of single current sampling for existing motors operating at medium and high speeds, and to provide an algorithm that is easy The implementation and control effect are relatively good, and the motor phase current reconstruction method based on symmetrical PWM carrier

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