고조파 전류 인가 방법을 이용한 EPS용 IPMSM의 토크리플 저감

Abstract

Recently, Interior Permanent Magnet Synchronous Motor (IPMSM) is widely used in various industry fields. IPMSM have advantage for a higher power density and a wider operating area. But IPMSM has a larger torque ripple in comparison with other type of motors and this is because back electromotive force have many harmonic components. Also, it can cause that the driver makes a mistake and feels nervous when torque ripple of Electric Power Steering (EPS) which is a sort of IPMSM is large. This paper suggests how to reduce torque ripple of EPS on load. First, the harmonic components of current offsetting harmonic components of back electromotive force can be found using the power equation. Second, those are added to fundamental current and inputted on load analysis. Last, each torque ripple of EPS for inputting the only fundamental current and the current including harmonic components is compared and it can show how large torque ripple is reduced using the harmonic current injection method.