Research on Minimizing Speed Harmonics of PMSM by Injecting Voltage Harmonics Based on Second-Order Generalized Integrator

This paper presents a novel method for eliminating harmonics in PMSM, aimed at eliminating current harmonics during the operation of PMSM. Harmonic elimination is achieved by injecting voltage harmonics, where the phase of the compensating voltage harmonics matches the phase of the harmonic currents, and the amplitude is adjusted by a PI controller based on the integral value of the extracted current harmonics. First, the impact of magnet disturbances and deadtime on motor control is analyzed, which mainly affects the amplitude and phase. Subsequently, the voltage expressions for the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$5^{\text {th }}$</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$7^{\text {th }}$</tex> harmonics are derived. Finally, an amplitudephase adjustment strategy based on an improved second-order generalized integrator (SOGI) algorithm is proposed. This method is characterized by low complexity and strong robustness, adaptable to various operating conditions, and offers excellent control performance. Experimental results validate the superiority and effectiveness of the algorithm.