Control Scheme for a Stand-Alone Wind Energy Conversion System for Better Efficiency of Battery Storage

摘要

The Power system requirement for isolated, low populated area is un-economical, if power is to be transmitted from far end, the initial cost, maintenance, will be too high, the line loss will also be more. Hence for such places stand alone wind energy conversion system (Non grid) with battery storage is a better option; provided the geographical attitude is higher and minimum velocity of wind is between 15 - 25 m/h. In general the wind force is not uniform throughout the day, it varies time to time. Hence the output power and frequency cannot be maintained uniformly to the consumer satisfaction. A control system is deployed for uniform power output and frequency under varying wind force. For obtaining this control pitch control is used, by adjusting the pitch control the power output and frequency maintained constantly. The next topic is storage device. Without storage device continuity of supply could not be maintained. The storage device generally costlier and the life expectancy will be short. To enhance the life expectancy some advanced technique like maximum power point tracking (MPPT) is used. By this control system the charging of battery is continuous and by adding some ripple the battery charging is better and the harmonic content is eliminated by avoiding overheating of the battery. The battery control system uses both constant current and constant voltage for making the high efficiency of battery banks and enhancing the life of the battery.