Low torque ripple spoke-type permanent magnet motor

摘要

Various implementations include a spoke-type rotor design that exhibits low torque ripple with competitive torque density. The rotor includes a rotor core, rotor core (RC) magnets, nonmagnetic caps disposed on an outer radial end of each RC magnet, and flux directing (FD) magnets disposed circumferentially between adjacent RC magnets. Each nonmagnetic cap has a radially tapered shape (e.g., trapezoidal). An outer radial end of each cap and an outer radial end of each RC magnet opening define an air gap therebetween. The magnetic flux directions of the RC magnets are circumferentially directed clockwise or counterclockwise, and the flux directions of circumferentially adjacent RC magnets are opposite from each other. The magnetic flux directions of the FD magnets are directed radially inwardly or outwardly, and the flux directions of circumferentially adjacent FD magnets are opposite from each other. The RC and/or FD magnets may include rare-earth free materials.