Improved application of resonant controllers for compensation of cogging force ripple in long-stator Permanent-Magnet Linear machines

Detent force is a typical drawback of Linear Permanent Magnet (PM) machines, particularly when accurate positioning or constant low speed is required. This kind of motor presents cogging force, force weakening on the transition areas, and saturation. This paper analyzes and improves a resonant controller in the force-current control loop to improve it´s behaviors. A force model obtained from Finite Element Models (FEM) is used as feedback in the control loop. Static force measurement to validate the models are presented. An experimental setup with a segmented long stator permanent magnet linear machine is used to validate the proposed control strategy.