DEVELOPMENT AND EVALUATION OF A BATTERY MANAGEMENT SYSTEM (BMS) FOR SMALL AUTONOMOUS PV SYSTEMS

摘要

The design, development and evaluation of a Battery Management System (BMS), for use in small autonomous PV systems is presented in this paper. The main functions of the BMS include charge control, overcharge protection, cell equalisation, under-discharge protection and short-circuit protection. The BMS was designed for outdoor operation and features programmable characteristics and external visual indication of system status. The BMS was designed for use with the Tadiran Li-Me AA size battery type with nominal values 800mAh capacity, 3.00V voltage, 250mA discharge current and 2.00V end of discharge voltage. The expected solar power input of a typical PV/Li-Me battery based system is in the range IWp to 5Wp. The development phases of the advanced BMS included laboratory prototype design, construction and testing. The final firmware development included features like variable current charging and battery de-passivation. Five BMS units were constructed and the performance was evaluated outdoors in three different test sites. The cost of 30Euro for the final product was achieved. The evaluation results show that advanced battery control has been achieved and the system operates satisfactorily.