A New Configuration for Wind/Solar Water Pumping System Based on a Doubly Fed Induction Generator

This paper proposes a new configuration for a standalone hybrid water pumping system that consists of a small-scale variable-speed wind turbine, a doubly-fed induction generator (DFIG), a battery storage system, a PV array, a boost converter, and a centrifugal water pump driven by a squirrel cage induction motor. The DFIG is connected to an inverter to extract maximum power under variable wind speed conditions. This inverter is also responsible for stalling the turbine when operating above rated wind speed. A PV array is used to charge the battery and the P&O technique is implemented for MPPT since the PV cells have nonlinear P-V characteristics. In this work, a comprehensive model that considers the mechanical, electrical and aerodynamic characteristics of a wind turbine system is used to model the new water pumping system configuration. The paper discusses the proposed configuration along with its control strategy and modeling, and presents simulation results that confirm its feasibility.

I. Introduction

In remote areas without a power grid such as mountainous regions or deserts, water pumping is the only viable method of ensuring a minimum water supply. Using renewable energy is the best way to overcome environmental and economic issues associated with the use of diesel generators. Among all the various forms of renewable energy, solar and wind energy are the most attractive as they are abundant and readily available. They are, however, dependent on seasonal variations, environmental conditions, and the day-night cycle and are intermittent and unreliable. Hybrid systems are therefore recommended to enhance the output power produced by purely PV or a purely wind systems and to make them more reliable.