Comparative Study of Sideband Electromagnetic Force in Internal and External Rotor PMSMs With SVPWM Technique

摘要

The permanent magnet synchronous motors (PMSMs) with space vector pulsewidth modulation (SVPWM) technique will inevitably introduce sideband current harmonic components around the carrier frequency. The armature reaction field caused by the sideband current interacts with the permanent magnet field, generating sideband electromagnetic force and resulting in high-frequency noise. This paper provides a comparative study of the sideband electromagnetic force in internal and external rotor PMSMs with SVPWM technique. First, the analytical model of the electromagnetic force in internal and external rotor PMSMs is established based on the Maxwell tensor method. The source, spatial order, and frequency of the electromagnetic force is obtained. Then, the spatial and temporal characteristics of the sideband force in internal and external rotor PMSMs with different pole and slot combinations are derived and investigated. The results show that the frequency characteristics of the zeroth order sideband force in internal and external rotor PMSMs introduced by SVPWM are identical. However, the frequency characteristics demonstrate significant differences for the nonzeroth order sideband force. Finally, the theoretical analysis is validated through the finite element and experimental results, respectively. This study is benefit for the source identification and reduction of high-frequency acoustic noise for PMSMs.