Study On A Stand-Alone Pv System With Hybrid Energy Storage

Accompanied by the rapid development of global economy, the consumption of primary energy became so rapidly, resulting in worldwide energy crisis and environmental pollution. Solar energy with its advantage of inexhaustible, safe, reliable and non-polluting caused human concern. However, with the development of large-scale photovoltaic power generation system, as well as the increasing of variety impact on power equipment, the energy storage device proposed new requirements. Therefore, the study of new energy storage device has a great significance. Based on the battery and super capacitor hybrid energy storage, this paper studied the independent photovoltaic power generation system.First, this paper analyzed three different kinds of structure of the battery and super capacitor hybrid system, and established the equivalent model of the battery and super capacitor directly parallel hybrid energy storage system. Based on the theoretical analysis of the equivalent model and aimed to the pulsating load, analyzed the improvement of hybrid energy storage system. According to the battery and charge or discharge characteristics of super capacitor, this paper used different charge or discharge control strategies to achieve regulation limiting. This paper used two-way half-bridge DC/DC converter to control the charging or discharging of the battery and super capacitor.Secondly, according to the characteristics of the solar cells, batteries and super capacitor bank brought an energy control strategy. The core of system energy management is based on the working status of solar cells, batteries and super capacitor group. This paper used the working status to control the one-way Boost converter, two-way half-bridge DC/DC converter1and two-way half-bridge DC/DC converter2running at the appropriate working mode, so that these three energy sources can work Coordinately to ensure efficient, stable operation and rapid response of the power supply system.Finally, this paper not only gave simulation model of the independent photovoltaic power generation system based on battery energy storage but also independent photovoltaic power generation system based on the battery and super capacitor hybrid energy storage. Simulation results showed that hybrid energy storage device is not only able to quickly meet the load requirements, but also free battery from the impact of high-current charge or discharge. So the hybrid energy storage device has improved output power capacity of the system and extended battery life.