Experimental comparison of a three- and a five-phase permanent magnet synchronous machine

Abstract A five-phase permanent magnet synchronous machine (PMSM) allows for the injection of a third harmonic current to produce an additional constant torque. When this torque component is superimposed on the fundamental torque component, the overall efficiency of the machine can be increased. This paper compares a three-phase and a five-phase permanent magnet synchronous machine with buried V‑shaped magnets. Both machines are inverter-fed and have a rated power of 15 kW at 1500 rpm. During the design process, it is ensured that both machines have the same thermal, geometrical, electrical, and mechanical constraints to allow for a fair comparison. The machines are analyzed at no-load conditions, during short-circuit operation and at rated and overload operation. A third harmonic current system is injected with varying amplitude and phase in the five-phase stator winding of the PMSM to investigate its impact on increased torque and efficiency.