A position sensorless motion control system of reluctance synchronous motor with direct torque control

This paper presents an implementation of position sensorless motion control system of reluctance synchronous motor (RSM) drives with direct torque control (DTC) for a industrial servo drive system. The control system consists of stator flux observer, rotor position/speed/torque estimator, two hysteresis band controllers, an optimal switching look-up table, IGBT voltage source inverter, and TMS320C31 DSP controller. The stator flux observer is based on the combined voltage and current model with stator flux feedback adaptive control for which inputs are current and voltage sensing of motor terminal with estimated rotor angle for wide speed range. The rotor position is estimated by observed stator flux-linkage space vector and compensated rotor angle in transient state. The estimated rotor speed is determined by differentiation of the rotor position. In order to prove the suggested position sensorless motion control algorithm, some simulations and actual experimental testing can be achieved. The developed position sensorless control system shows good motion control response characteristic results and high performance features with 1.0 kW RSM having 2.57 ratio of d/q reluctance.