A Study about the Influence of Rotor Position of IPMSM on the Maximum Voltage on Motor Terminals under Inverter-fed Operation

In this research, a comprehensive method is developed to study the influence of rotor positions on motor terminal overvoltage in interior permanent magnet synchronous motor (IPMSM) under inverter-fed operation. The developed approach helps understand the intricate interactions between inverters, cables, and electrical machines. In order to analyze the interactions, highly accurate grey box models for both the IPMSM and power cables are required. In developing the model, the asymmetry between phases caused by the interior permanent magnets in the IPMSM is considered. The relative errors in the developed motor model are less than 4% for all rotor position regarding the impedance modeling. Additionally, the cable model considers the frequency-dependent mutual inductances among various phases and outer shields, which is not found in the state-of-the-art. With the help of the established motor and cable models, the influence of rotor positions on the differential mode overvoltage at motor terminals is studied. The relative difference in the peak voltage values at the motor terminals is less than 5 % at different rotor positions under inverter-fed operations.