Cogging torque reducing in electric machine by poling modification of magnetic circuit

The paper presents results of permanent magnet electric machine's magnetic circuit simulating research. During researches the magnet pole-arc width angle had been changing - adjacent pole-arcs took the angle dimension (30 degrees - alpha) and (30 degrees + alpha). The aim of research was determining the optimal value of parameter a, for which cogging torque takes the smallest value but the electromagnetic torque value is not changing. Conclusion from the research results proves that by application two of different magnet pole-arcs in rotor the cogging torque can be decreased about 30%.