Electromagnetic Torque-Based Model Reference Adaptive System Speed Estimator for Sensorless Surface Mount Permanent Magnet Synchronous Motor Drive

This article proposes simple and robust electromagnetic torque-based model reference adaptive system speed estimator with cascaded pseudoderivative feedback controller for sensorless surface mount permanent magnet synchronous motor (SMPMSM) drive to improve its performance at standstill and low-speed regions. The proposed estimator is formed using instantaneous and estimated electromagnetic torque. Using small signal modeling, the stability and sensitivity analysis are performed. Results show that the estimator is stable over a wide speed region (including low-speed regions) and exhibits robustness against uncertainties in machine parameters. The proposed estimator is implemented for the 1.5-kW laboratory prototype SMPMSM drive using field programmable gate array (FPGA) ALTERA Cyclone II. Experimental results demonstrate the efficacy of the proposed scheme under different test conditions viz., over a wide adjustable speed range which includes different low-speed regions and standstill, i.e., 157 to -157 rad/s at different load conditions with uncertainty in machine parameters.