Reduction of Permanent Magnet Eddy Current Losses in High-Speed Permanent-Magnet Synchronous Motors Using a Three-Level Inverter

High permanent magnet losses of high-speed permanent-magnet synchronous motors will lead to irreversible demagnetization of permanent magnet, which has a serious impact on the motor performance. For high-speed motors, the current harmonics caused by the inverter is one of the key reasons causing permanent magnet eddy current. In this paper, the effect of different inverters on permanent magnet losses of high-speed permanent-magnet synchronous motors is investigated. Finally, the analysis is verified by the coupling simulation method. The results show that the effect of current harmonics on the permanent magnet eddy current losses can be greatly reduced when a three-level inverter is applied. Compared with a two-level inverter, the three-level inverter is more suitable for high-speed motor.