The Four-Pole Planetary Motor

Abstract:
Electric drive systems usually gain their high power density by using a motor with a high rotational speed at a certain torque. To increase the output torque the motor needs to be equipped with an additional gearbox. The speed and therefore the output power are often limited by the mechanical strength of the rotor material. This paper proposes a multi-rotor drive system, which allows to further increase the maximum output power by splitting the motor into several partial motors. The structure of the multi-rotor machine, which behaves like a single three-phase motor, is derived for the case of using four-pole permanent magnet rotors. To verify the operating principle a prototype is built and measurements are presented.