Performance Investigation and Improvement of Linear Vernier Permanent Magnet Motor for Servo Application

With its high thrust density and low force ripple, the linear vernier permanent magnet motor (LVPMM) is regarded as a good competitor for linear servo applications. However, typical LVPMMs have shortcomings, such as phase imbalance, a long distributed-winding end, and low power factor. The goal of this work is to present a thorough analysis-based approach for performance enhancement that addresses all three flaws while enhancing the LVPMMs high thrust density advantage. Thanks to the proper slot/pole-pair combination, Halbach array PM, and a special three-modular structure, the proposed LVPMM improves thrust density by 28%, reduces force ripple to 1.2%, increases power factor by over 40%, and nearly eliminates three-phase imbalance when compared with those of a conventional LVPMM. Manufacturing and testing a 2.2 kW/2200 N prototype has confirmed the viability of the theoretical analysis and improvement process.