Electronic motors capable of pole-changing and variable machine constants

The motors used in electrical vehicles and electrical appliances operate at variable speeds using flux-weakening control. The flux-weakening current, which depresses the voltage at high speeds, causes significant copper and core losses. Therefore, we developed a new technique for changing the number of poles and the machine constants in a permanent magnet motor on the basis of its speed. In this paper, we propose a novel motor capable of changing the number of poles and the machine constants and clarify its principle and basic characteristics. The results show that the permanent magnet motor can vary the motor´s induced voltage can be varied from 24% to 100% by pole-changing.