Permanent Magnet Synchronous Machines With Nonuniformly Distributed Teeth

In this article, an increasing interest for permanent magnet synchronous machines with low torque ripple and low vibration is observed. The purpose of this article is to investigate the topology of nonuniformly distributed teeth and its influence on cogging torque, tooth ripple harmonics, and torque ripple of permanent magnet synchronous machines. The topologies with different numbers of nonuniformly distributed teeth are investigated. Analytical procedure is developed to illustrate the impacts of nonuniformly distributed teeth on cogging torque and unbalanced magnetic pull, and then identify the appropriate nonuniformly distributed teeth. A commercial 10 kW 8-pole 48-slot V-shaped interior permanent magnet (IPM) machine is taken as the reference base machine. The machines with two and six nonuniformly distributed teeth are chosen to make an overall comparison with the well-known skewing slots. The machine with two nonuniformly distributed teeth is finally chosen to be fabricated. Intensive experiments, including cogging torque, back electromotive force, load current, efficiency, and instantaneous torque, are done.