Research And Application Of Supercapacitor Energy Storage System In The Photovoltaic Power Generation System

As a green energy storage device, supercapacitor has the advantages in the energy storage, including a fast charging and discharging speed, high power density, long cycle life, high and low temperature performance. In addition, it also has the maintenance-free, no pollution etc. On account of that, it has broad prospects in the energy storage. To aim at the defects on the battery energy storage, the applications of supercapacitor in the field of energy storage were studied in the paper with stand-alone photovoltaic (PV) system as an example.The supercapacitor energy storage principle was analyzed, and the equivalent circuit model was introduced. The test methods of relevant parameters were given by theory analysis. Supercapacitor charge-discharge characteristics were studied by related experiments, and some technical problems in the supercapacitor energy storage system were studied and discussed.PV cell and its working principle were introduced. According to its equivalent circuit and engineering mathematical model, the simulation model of PV cell in MATLAB was created. Maximum power point tracking (MPPT) principle of PV cell was introduced. Several common MPPT methods were analyzed and compared, and then this paper presents a modified MPPT method. MPPT control system with supercapacitor as energy storage is set up, and its main circuit and controlling unit are designed. Simulation and experiment results show that the system with this MPPT method used has better tracking speed and accuracy, and under varying environmental conditions, it's very stable.The small power test platform of stand-alone PV system based on supercapacitor energy storage system is set up, and its overall structure and control system are designed. What's more, the energy flow and the role of supercapacitor in system are also analyzed. According to the energy storage characteristics of supercapacitor, the supercapacitor charging and discharging controller are separately designed, including the design of the hardware portion of the controllers. Through the analysis of charge and discharge control strategy, the relevant software is designed. Simulation and experimental results demonstrate the feasibility of the system as well as good reliability and stability.