An Efficient Control Scheme of Self-Reliant Solar-Powered Water Pumping System Using a Three-Level DC–DC Converter

Abstract

This article proposes a reliable and cost-effective solution of water pumping system for the off-grid community, where the grid supply is not available. The designed system uses an 8/6 pole, four-phase switched reluctance motor (SRM) with a midpoint converter as a drive to pump the water. A three-level boost converter (TLBC) is used as an intermediate power conversion stage between the solar photovoltaic (PV) array and motor-pump. The TLBC has many benefits such as low voltage stress across devices, small inductor size, and ability to operate with a wide voltage range, which make the proposed system highly efficient and cost-effective. An efficient control technique is developed for the designed system, which simultaneously maximizes the PV array power and equalizes the voltages across split capacitors of a midpoint converter under all working conditions. An online flux optimization with a single-pulse mode of the SRM drive is developed and implemented. The developed control scheme eliminates the need of any phase current sensor, and the motor speed is fully governed by the available PV array power. This article proposes a new technique to emulate the characteristics of centrifugal water pump using a dc generator. This technique provides a simple solution to test the centrifugal solar pumps in the laboratory. The system under study is simulated in MATLAB/Simulink, and its different responses are examined under all possible working conditions. The simulated results are authenticated by the test results obtained through a developed prototype in the laboratory.