PV power system based MPPT Z-source inverter to supply a sensorless BLDC motor

This paper proposes a new PV power system feeding a sensorless brushless dc motor (BLDC) driving a water pump. A Z-source inverter (ZSI) is controlled to extract the maximum power from PV array and supplies the BLDC motor instantaneously. The BLDC motor is driven with variable reference speed dictated from instant maximum PV power by a hysteresis current control loop. Despite the conventional PV water pumping systems, employing a two stages converter, the proposed system enjoys one stage power conversion. Therefore, less number of power switches, less switching losses and lower cost are obtained. By proper designing of control system parameters and maximum power point tracking (MPPT) method for PV array, good steady state and transient performances have been achieved in response to different operation conditions for PV array. Sensorless drive with low torque ripple is provided for the BLDC motor. The system was simulated by PSCAD/EMTDC software for a PV array of 1 kW.