An AC Copper Loss Calculation Scheme of Synchronous Motor with Rectangular Conductors Considering Pulse Width Modulation Harmonics

This paper presents an efficient method for calculating AC copper loss in interior permanent magnet synchronous motor (IPMSM) with rectangular conductors, considering pulse width modulation (PWM) current harmonics. The inverter-fed current for driving IPMSM can be decomposed into fundamental and harmonic currents. The proposed method first utilizes magneto-static finite element analysis (MS FEA) to compute the magnetic vector potential (MVP) generated by the fundamental current. Next, the frozen permeability method linearizes the FEA model by keeping the permeability of iron core. A single harmonic current is input into linear-MS FEA to compute MVP without permanent magnet excitation. The MVP of other harmonic currents are derived using linear fitting. The linear fitting of MVP is validated with FEA. Finally, the AC copper loss is then calculated by summing the contributions from the MVP of each current component.