Improved Harmonic Iron Loss and Stator Current Vector Determination for Maximum Efficiency Control of PMSM in EV Applications

The accurate control of interior permanent magnet synchronous machine (IPMSM) and drive in electric vehicle applications is vital for achieving superior performance over a wide range of speeds and loads. Many control methods such as loss minimization and maximum efficiency (ME) have been developed to improve the efficiency of the motor-drive, by mainly considering the controllable fundamental losses. This article includes the effect of stator harmonic iron losses caused primarily by inverter sideband time harmonics that contribute to a significant amount of controllable electrical losses in IPMSMs. The sideband harmonic iron losses have been analytically modeled using a novel dq -axis model incorporating harmonic iron loss resistance. Subsequently, the harmonic iron losses have been included in an offline procedure used to determine optimal current advance angle for increased motor efficiency. The improved IPMSM losses and subsequently, the analytical efficiency models have been derived by considering varying motor parameters due to saturation and cross-saturation effects. The accuracy of the developed model and the improved ME control using the optimal current angle have been validated using numerical simulations and experimental investigations on a laboratory IPMSM.