Adaptive SMC Based DTC of Position Sensorless PMSM Driven Solar PV Water Pumping System

Abstract

In this paper, an adaptive sliding mode controller (ASMC) based direct torque control of position sensorless permanent magnet synchronous motor (PMSM) driven single stage solar photovoltaic (PV) water pumping system is proposed. An ASMC based DTC is used as it reduces the influence of external disturbances and parameter variations on the proposed system since the conventional SMC is robust only in the course of sliding mode. To operate solar PV array at its maximum point, a modified perturb and observe (PO) maximum power point tracking (MPPT) algorithm is used. The MPPT algorithm is based on fractional short-circuit current (FSCC) calculation. It is used due to its better tracking performance under rapidly changing solar irradiation and low-power oscillations around MPP. This increases the efficiency of FSCC-PO algorithm in comparison to conventional PO-MPPT algorithm. The angular rotor position is estimated using stator flux linkage based method, thus eliminating the mechanical rotor position sensors. This improves the reliability and decreases overall cost of the system. The 3-level and 2-level hysteresis controllers are used for processing torque error and flux error respectively. The appropriate switching states based on torque and flux error are, applied to the inverter. A laboratory prototype of the proposed system is made. The experimental results are obtained for steady-state, starting and dynamic conditions under variable solar irradiation.