Date of Award

May 2017

Degree Type


Degree Name

Master of Science



First Advisor

David Yu

Committee Members

Seyed Hosseini, Chiu Law


Energy Storage System, Frequency Analysis, Photovoltaic, Power Fluctuation Smoothing


As the Hybrid Energy Storage System (HESS) has the advantages of both power-based and energy-based energy storage devices. It is suitable for a microgrid to smooth the power fluctuation. Analyze the power data of a grid-connected photovoltaic (PV) power station. This research considers grid-connected PV requirements to join the HESS and take advantage of the HESS charge and discharge characteristics to reduce the problems caused by light intensity and temperature change of grid-connected PV power output fluctuations. Using battery optimization control strategies to reduce power and capacity of the HESS configuration. This paper Analyze the effect evaluation when HESS rated power and capacity changed. In addition, proposed a strategy that using methods to decide the most representative day among a year. Fast Fourier Transform (FFT) is applied to transform the solar radiation to the frequency domain. The simulation results verify the feasibility of this strategy and method.