PF-MRAC-Based Elimination of Sensors in Solar-Powered PMSM Drive-Based Water Pumping System

The water pumping system powered by solar photovoltaic (PV) array and driven by permanent magnet synchronous motor demands a current-sensor to operate PV array at its maximum power and an encoder to implement field-oriented control of motor. Reduction in reliability and increment in system cost are the two major drawbacks that demand their elimination. Even the application of system for locations with high ambient temperature is limited as these sensors are temperature sensitive. In this work, power-factor-based model-reference adaptive-control (PF-MRAC) to remove encoder as well as current sensor is presented. Even stator winding resistance and rotor flux linkage are estimated by PF-MRAC. Thus, presented MRAC is independent of parameter uncertainty contrary to conventional MRAC. Besides, developed PF-MRAC does not contain integral and derivative operators, and hence, it is free from saturation and noise problems. The estimated speed is used for the estimation of PV power, which is then used for extracting maximum power from PV array, thereby removing current sensor. Besides, an additional converter is not required for realization of presented maximum power point tracking method. The developed PF-MRAC is realized on dSPACE Microlab box platform, and test results are acquired for various operating scenarios on laboratory prototype.