SPV array powered zeta converter fed SRM drive for water pumping

Abstract

This paper demonstrates the utilization of solar photovoltaic (SPV) array produced electrical energy for low cost and efficient water pumping using simple, robust and efficient switched reluctance motor (SRM) drive. For increasing the efficiency of pumping system, an incremental conductance (InC) algorithm based MPPT technique is employed with SRM drive. A DC-DC zeta converter operated in continuous conduction mode (CCM) is used in midway between SPV array and SRM drive to provide limitless region for operation of MPPT and also for soft starting of SRM. The mid-point converter having two split capacitors is used to provide the required voltage pulses for phase windings excitation of all four phases of SRM drive. The mid-point converter operates as an electronic commutator to reduce the switching losses and power dissipation of the converter. Both the inductors of zeta converter are operated in continuous conduction mode (CCM) which results in minimal stress on converter elements. Unlike Cuk converter and SEPIC (Single-Ended Primary Inductance Converter) type buck-boost converters, zeta converter does not need additional circuit to limit the inrush current and does not require any overload protection. The speed of SRM drive is controlled with variable DC link voltage of mid-point converter and it depends upon the different environmental conditions and insolation levels of SPV array.