Summary form only given. This paper presents the design criteria for the detent force reduction of the permanent magnet linear synchronous motor (PMLSM) with Halbach array. There are three approaches to improve the power efficiency of short PM pole-type LSMs: (1) the comparison of the magnetic field and forces of two types of PMLSM-a PMLSM with a Halbach array (HA-PMLSM) and a PMLSM with a conventional array (CA-PMLSM); (2) the determination of PM length/slot pitch of the two types with minimum detent force; and (3) the comparison of the force performance of two types with the minimum detent force.