Study On Energy Storage Inverter And Smoothing Of PV Power Fluctuation

With the depletion of fossil fuels in the world, as well as the world’s growing environmental pollution, new energy generation technologies have a very good application prospect, with the feature such as environmentally friendly and renewable. However, randomness and instability of some new energy generation cause a great impact on power system security, reliability, and efficient operation. In order to smooth the power output, improve reliability and reduce the volatility of new energy power generation, energy storage system cooperating generation becomes an important development direction.Firstly, this paper analyzes the various equivalent circuits for storage batteries, and improves the typical equivalent circuits. Moreover, new model is presented based on a simple equivalent circuit and the third-order dynamic equivalent circuit combination. This model has been verified by using PSCAD/EMTDC simulation platformAfter using double-loop control strategy in PSCAD/EMTDC platform for numerical simulation, the different charge-discharge mode (constant voltage, constant current, constant power) characteristics comparison is made, and the characteristics of voltage-current, which is the output of the energy storage system, is concluded under different charging and discharging modes. There are different switching methods of charging and discharging between different modes. And an improved control strategy with softening control links is proposed to improve the smooth of switching current transition curve. According to the characteristics of the battery condition, the three variables controlled method is proposed to control the charge-discharge termination.Then, the paper analyzes the different topology of light^features combined storage system, and uses the AC side parallel topology to do a deep research in suppressing the solar power flat wave in energy storage systems. Not only that, a new algorithm is presented to calculate the flat fluctuation compensation power and is verified in PSCAD/EMDTC simulation platform.Finally, the paper analyzes a number of failures in the energy storage inverter prototype test.