Analysis of brushless dual-mechanical-port dual-electrical-port machine with spoke-array and non-equidistant three-segment-array rotor

Brushless dual-mechanical-port dual-electrical-port machine (BDD) have received widespread attention due to their advantages, including simple structure, high reliability, and compact size. To improve machine torque density and reduce torque ripple, a novel brushless dual-mechanical-port dual-electrical-port with spoke-array and non-equidistant three-segment-array rotor (BDD-SNTR) machine is proposed. The permanent magnets (PMs) of the inner and outer rotors adopt non-equidistant three-segment-array and spoke-array structure, which can effectively improve magnetic flux density. The two sets windings of the machine share a stator slot and form a permanent magnet synchronous motor (PMSM) part and a field modulation synchronous motor (FMSM) part with the inner and outer rotors respectively. The structure and working principle are firstly introduced according to the principle of magnetic field modulation, and the magnetic equivalent circuit model is established and the operating characteristics are analyzed; The proposed BDD-SNTR machine is compared with the conventional BDD machine and the spoke-type BDD machine by finite element simulation method; Finally, multi-objective optimization and simulation analysis of the BDD-SNTR machine are conducted on the main parameters based on Box-Behnken design. The results show that the novel BDD-SNTR machine can achieve decoupling of torque and speed, and has higher torque density and lower torque ripple.