A Pulse-injection Based Position Sensorless Control of SRM with Adaptive Commutation Angle For EV

Abstract

This paper presents an SRM (Switched Reluctance Motor) drive, through pulse-injection based position sensorless method with adaptive commutation angle for light electric vehicle (LEV) application. An asymmetric half-bridge (ASHB) converter is connected to a 28 A, 1.25 kW, 12/8, 3-phase, SRM with a Li-ion battery at the input for the required purpose. The high frequency voltage pulses are injected in idle phases of the machine, which causes low magnitude current pulse in the phases. The turn-on and turn-off angles are varied through advance angle control online and based on these angles, two different threshold currents are obtained. The injected current pulse, upon comparison with these threshold currents provide two different rotor positions for the turn-on and turn-off the phases. The current pulses are kept low, through adjusting the duty of the injected pulse, such that the torque induced by these pulses are neglected and do not affect the average torque of the machine. Moreover, for acceleration and starting of the SRM, the phase currents are kept, more than the rated current of the machine, to generate higher torques during such conditions, for vehicular application, in practical case scenario.