Comparative Study of Speed Ripple Reduction by Various Control Methods in PMSM Drive Systems with Pulsating Load

This paper compared the speed ripple reduction of three different control methods in a permanent magnet synchronous motor when the load torque varied according to rotor position. Generally, speed ripple occurs when the load pulsates. The methods were voltage-current phase difference control, current vector control, and direct torque control. Speed ripple reduction was performed using the angular velocity of the inverter compensation, signal injections to the q-axis current and reference torque, and gain design. This paper describes and compares the effectiveness of each speed ripple reduction method.