Adaptive force ripple suppression in iron-core permanent magnet linear motors

This paper presents the design and realization of an adaptive dither to reduce the force ripple in an iron-core permanent magnet linear motor (PMLM). A composite control structure is used, consisting of three components: a simple feedforward component, a PID feedback component and an adaptive feedforward compensator (AFC). The first two components are designed based on a dominant linear model of the motor. The AFC generates a dither signal with the motivation to eliminate or suppress the inherent force ripple, thus facilitating smooth precise motion while uncompromising on the maximum force achievable. Real-time experimental results verify the effectiveness of the proposed scheme for high precision motion trajectory tracking using the PMLM.