Improvement of Speed Ripple in Low Speed Range for PMSM using Observer

관측자를 이용한 영구자석형 동기모터의 저속영역 속도리플 개선

Generally, we often use a speed sensor based on a rotary encoder and we can obtain a speed information by counting the increased or decreased number of encoder pulses in a sampling period. However, these speed measurement systems do not inherently produce a true, instantaneous speed information and them the speed ripple is generated by speed measurement errors. In order to overcome this problem, speed observer is used for the accurate speed measurement and improvement of speed ripple for Permanent Magnet Synchronous Motor (PMSM) in this paper. Speed observer estimates the instantaneous speed at each sampling instant. This estimated speed signal is then used as the speed feedback signal for the speed loop control. The proposed speed observer system is proved simulation using SABER simulation S/W.