Design and analysis of novel asymmetric-stator-pole flux reversal PM machine

This paper proposes a novel flux reversal permanent magnet (FRPM) machine with asymmetric-stator-pole (ASP) configuration. Different from the conventional FRPM machine with uniform “NS-NS-NS” PM sequence, the proposed ASP-FRPM machine is characterized by a “NSN-S-NSN” magnet arrangement. Hence, the interpolar flux leakage is significantly reduced with the developed design, which can improve the torque capability. The machine topologies, features and operating principle are introduced, respectively. A simplified magnetic circuit model is established to reveal the underlying flux leakage reduction mechanism of the ASP design, and the rotor pole number is analytically optimized as well. The design parameters are then globally optimized so as to improve the torque quality. In addition, the electromagnetic characteristics of the ASP- and conventional FRPM machines are compared. Finally, experiments have been carried out to validate the theoretical results

Overview of Stator Slot-opening Permanent Magnet Machines

In the past few decades, the stator permanent magnet (PM) machines have attracted much research attention because of their reliable rotor structure, high power density, wide speed range, and strong fault-tolerant ability. Among the recently proposed stator PM machine topologies, the stator slot-opening PM (SS-PM) machines are becoming increasingly popular because of their higher stator space utilization and robust rotor structure. According to the SS-PM magnetization direction, the SS-PM machines can be classified into three categories, namely, the tangentially magnetized stator slot-opening PM (TMSS-PM) machines, the radially magnetized stator slot-opening PM (RMSS-PM) machines, and the compound magnetized stator slot-opening PM (CMSS-PM) machines. The associated working principle and electromagnetic performance of different SS-PM machines can be diverse. Therefore, this paper gives an overview of SS-PM machines in terms of machine design, working principle, and machine performance. A qualitative performance evaluation and comparative study of SS-PM machines are presented, and the future challenges and potential opportunities in the SS-PM machine design are discussed