Sensorless vector controllers for induction motor drives

The development and implementation of sensorless vector controllers based on stator-flux-oriented control (SFOC) and rotor-flux-oriented control (RFOC) will be presented. For flux estimation, instead of measuring phase voltages directly or estimating phase voltages indirectly using switching states and DC-link voltage, the voltage command for inverter control is used and therefore, only current sensors are required. The effect of dead time on speed control at low speed range will be highlighted and the details of dead time compensation will be presented. Simulation results from a model-based computer-aided design approach using Simulink, and experimental results will be presented in the paper to confirm the theoretical analysis and hardware design.