A SOLAR CELL-BASED INVERTER WITH IMPROVED BATTERY LIFE FOR INDUCTION MOTOR

Abstract

This paper deals with the design and prototype development of an inverter to feed AC power to an induction motor coupled with a submersible pump. In this type of load, input power is proportional to the cube of the speed. The inverter is fed from a 48 V rechargeable battery, which is charged through the solar panel. Four numbers of the solar panel each of 165 W, 12 V rated are used for charging the battery. The basic intention of this research work is to start an induction motor with lower voltage and lower frequency, keeping v/f constant, such that the starting current is low. This concept can be utilized to run a submersible pump in a remote area where there is no electric power supply or where there is a problem in the distribution system. Submersible pumps are normally operated for a small interval (60 to 180 min). This energy can be supplied by a 48 V, 75 Amp-Hour Lead Acid type rechargeable battery. The experiment has been conducted with a Lead acid battery but the Lithium Ion battery gives better performance. The solar panel (cell) is used to charge the battery for around 8 hours from morning and with the fully charged battery, the pump is run through an inverter for a time of around 150 min. An inverter has been designed to run a 1 hp induction motor coupled with a submersible pump. The motor is started with low voltage with v/f control. Gradually the full voltage is applied and the motor runs at the rated speed. After an operation of a preset time, the motor is stopped. With VVVF drive the battery life has increased compared to a Direct online starter.