Investigating the Effects of PWM Currents on a High-Speed PMSM for an Aerospace Application

This paper discusses the impact of Pulse Width Modulated (PWM) current waveforms on electromagnetic losses and thermal characteristics of a high-speed PMSM designed for an aerospace application. The PWM effects are studied on a Surface Permanent Magnet Synchronous Motor (SPMSM) of 150 kW, 20000 rpm designed for an aerospace application. A 3D-Finite Element Model (FEM) of the machine is used for analysis in JMAG software. First, the machine model is studied for various electromagnetic losses using an ideal sinusoidal current waveform. These losses are used to study the thermal characteristics of the machine using Motor-CAD. The PWM currents are generated by modelling the motor drive with a 3-Level Active Neutral Point Clamped (ANPC) converter controlled by Field Oriented Control (FOC) algorithm in PSIM software. The machine losses are analyzed in FEM software by feeding the PWM current thus obtained. Using the thermal model of the machine developed in Motor-CAD, the thermal characteristics are studied. The switching frequency of the inverter is varied over a range of values to investigate its effect on the losses and thermal characteristics. Thus, this paper presents the effect of PWM current ripples on the electromagnetic losses and thermal characteristics of a high-speed machine.