Comparison of low-cost-implementation sensorless schemes in vector controlled adjustable speed drives

The paper describes the comparison between different high-performance low-cost-implementation techniques for the estimation of the rotor flux in medium-high speed sinusoidal AC motor drives. In sensorless estimation, rotor flux is estimated from measured terminal voltages and currents, and is used as a feedback in vector control schemes, achieving almost the same high-performance of sensored drives. At high speed, a key point is the robustness at parameter variations of estimators, which use only integration and feedback summation and observers that use more complex approximate differentiation. The paper points out some implementation differences between a classical open loop rotor flux estimator based on the voltage model, and a more complex Luenberger rotor flux observer when a low cost high performance STM32 microcontroller of ST Microelectronics, is used. Comparison of these two schemes is performed either in simulation and experimentally.