IPMSM motion-sensorless direct torque and flux control

The paper presents a rather comprehensive implementation of a wide speed motion-sensorless control of IPMSM drives via direct torque and flux control (DTFC) with space vector modulation (SVM). Signal injection with only one D-module vector filter and phase-locked loop (PLL) observer is used at low speeds to estimate the rotor position and speed, to be used in the stator flux observer and, respectively, as speed feedback. A combined voltage-current model flux observer suits the whole speed range, while the current model fades away as speed increases. PWM and inverter nonlinearities compensation provides for a smooth current waveform even at 1 rpm. The paper demonstrates through ample experiments a 1750 rpm/1 rpm speed range full-loaded with sensorless DTFC-SVM.