Position sensorless torque control of switched reluctance machines

Based on the recently developed PWM-based direct instantaneous torque control (PWM-DITC) this work presents a position sensorless torque control of switched reluctance machines (SRMs). The developed control offers a constant and position independent machine torque while operating in motoring as well as generating mode. For estimating the rotor position without position sensor, measured phase currents and applied phase voltages are evaluated using the position dependent magnetic characteristic of the machine. Through combination of two different methods, the rotor position can be estimated over the entire operating range. Furthermore, this work presents a method to measure automatically all for PWM-DITC required machine characteristics using the machine inverter. As for the torque control, also for the automatic commissioning process no position sensor is used. Within the initialization sequence, which has to be performed only once for each machine, the required inductance, flux-linkage and torque characteristics of the machine are subsequently acquired. The user only has to provide a few basic machine parameters as e. g. the number of phases or the maximum phase current. The combination of sensorless torque control and automatic determination of machine characteristics offers a faster and more effective commissioning of new SRMs. As no hardware modifications for measuring additional signals are required, the presented approach provides a cost effective solution for controlling the torque of SRMs in various applications spanning from the automotive to the industrial sector.