Four-quadrant force control with minimal ripple for linear switched reluctance machines

Linear switch reluctance machine (LSRM) has been tried to act as an alternative generator for direct drive linear wave energy converter (WEC). Many researchers have proposed new topologies of LSRM to improve the power density, efficiency and reliability. However, the control methods for LSRM applied in direct drive WEC have been paid little attention, especially control methods considering the wave energy generator operating characteristics. In this paper, according to the generator control requirements of the direct drive WEC, force control algorithm for LSRM operating in four quadrants without a speed closed loop is put forward. The force ripple of LSRM is suppressed using force sharing function method. The four-quadrant control is easy to realize requiring only phase currents information. Simulation results validate the proposed method and indicate that LSRM is able to be used as the generator for direct drive WEC.