A wedge secondary for suppression the thrust ripple is studied, based on the distribution of air gap flux density and current density of secondary along the longitudinal direction of long primary double sided linear induction machine (LPDLIM) with plates secondary. The wedge structure at the secondary exit end changes the distribution of air gap flux density and secondary current density, thus reducing the thrust ripple of the motor. The influence of wedge size on thrust and force ripple performance is researched. The calculation results show that the wedge secondary can effectively reduce the thrust ripple and improve the thrust density of the LPDLIM, although the output thrust is reduced slightly. The comparison and analysis with the calculation results of the plate and wedge secondary LPDLIM show that the wedge secondary can effectively suppress the thrust ripple of the motor with any length secondary.

DLIM， Wedge， ripple， thrust