Modified SEPIC Converter Utilizing an Improved P&O Algorithm for Design of Low Cost and Efficient Solar Energized Water Pump

Abstract

This paper proposes a reliable and an efficient PV (Photovoltaic) powered water pump using a modified SEPIC converter with high static gain. The modified SEPIC converter has low switch voltage stress with high efficiency. It provides almost twice the static gain as compared to conventional boost converter and provides relatively large area for execution of maximum power point tracking (MPPT) controller. The switched reluctance motor (SRM) drive speed is controlled by using pulse width modulation (PWM) of a mid-point converter using only one voltage sensor. It supports to reduce the size of DC link capacitor and provides soft starting to drive via regulating the DC bus voltage. The operation of modified SEPIC converter in continuous inductor current mode (CICM) minimizes the stress on its devices and improves its conversion performance. An improved P&O (Perturb and observe) MPPT technique is used in proposed system. This MPPT controller has an additional advantage of regulating the flow rate of water pumping by adjusting the duty cycle of proposed DC-to-DC converter. The design procedure of system is described and a test bed is developed to verify its aptness under changing climate situations.