Multi-pole ratio single-winding pole-changing permanent magnet motor design and analysis

Pole-changing permanent magnet (PCPM) motors have advantages over traditional permanent magnet synchronous motors (PMSM) in high-speed applications. However, changing the pole number of a motor requires reconstructing the stator winding. This increases both the cost and complexity. To solve this problem, a new type of single-winding PCPM motor with a pole-slot combination satisfying the rule of 2p_a + 2p_b = Z (the sum of the number of poles of the motor before and after the pole-changing is equal to the number of slots) is proposed in this paper. The multi-pole ratio pole-changing of the PCPM motor can be realized by combining the single-winding structure with another single-winding structure that satisfies the p_a + p_b = Z (the sum of the number of pole pairs of the motor before and after the pole-changing is equal to the number of slots) rule. Through this method, there is no need to reconstruct the stator winding when a pole is changed, Only by changing the phase sequence and direction of the armature current, the switching process is rapid, and the online pole-changing can be realized. This single-winding pole-changing method can flexibly realize the conversion of three pole number modes without increasing the additional winding cost and complexity. Finally, the rationality of the proposed pole-changing method is verified by finite element analysis (FEA).