Investigations of hysteresis based direct torque controlled and field oriented controlled IPM drives for electric vehicle applications

Abstract

Direct Torque Control (DTC) techniques are widely used in the control of AC machines as an opponent of space vector pulse width modulation (SVPWM) based field-oriented control (FOC). In the literature, hysteresis-based DTC (HB-DTC) is a vast majority of DTC techniques as the technique do not require a position resolver or an encoder. In this study, HB-DTC and FOC techniques are compared in detail by paying particular attention to current distortions, torque ripple and computational burden. In both techniques, the results have been obtained by simulating a 4.1 kW interior mounted permanent magnet synchronous (IPM) motor which has been designed and manufactured for research and development for electric vehicle traction applications. The results validate that although the HBDTC drives, have pros such as having less computational burden on the processor and eliminating the need for a position sensor, they have relatively much current distortions and torque ripple and hence the results are much deteriorated. Since the modern processors can easily deal with higher computational burden and field-oriented control is feasible in real time, it has been validated by extensive simulations that FOC based IPM drives are superior to their HB-DTC counterparts.