2020 Volume 9 Issue 1 Pages 43-50
In order to reduce the fluctuation in the power grid due to the power generated by renewable energy sources, a grid connected hybrid energy storage system, which combines lithium-ion batteries and ultra-capacitors is used. In this paper, a new high-efficiency charge/discharge control method for power division as well as stored energy balance is proposed. The battery bank, ultra-capacitor bank, and power converters are individually analyzed. The control method is based on the high efficiency voltage range (HEVR), which is a new method of determining the highest efficiency work-point of the energy storage systems. A 1kW scaled prototype is used to assess the performance of the proposed system. The experimental results show that the proposed system achieves a higher total efficiency than the conventional method, while being able to control the energy balance of the storage devices.
