Research On Photovoltaic Energy Storage System Using Retired Power Battery

Many inevitable factors such as volatility and intermittentness exist in the field of new energy power generation.These factors have a universal impact when using light energy and wind power to generate electricity.These unavoidable factors will cause the output power to fluctuate,and traditional battery energy storage costs are high.The retired power battery of electric vehicles has very good energy storage performance and can be used in the optical storage system to save investment costs.At the same time,it also eased the market pressure for a certain number of retired power batteries to enter the reuse stage.The thesis first explains the research background and significance of using decommissioned power batteries as energy storage.Then,from the mathematical model of the entire optical storage system and the energy management control strategy,the current research situation is explained,and the research hot issues are raised.The following is the main research content of this article:(1)Photovoltaic modules,energy storage devices,loads,and power grids together form a solar energy storage system.The working mode principle of the whole system is: the photovoltaic energy is used to control the output of the photovoltaic module through the photovoltaic maximum power tracking(MPPT)through the pre-stage Boost circuit,and the energy can maintain bidirectional flow with the help of the energy storage converter(PCS)transmission.(2)As a topological structure,the performance of the three-phase half-bridge voltage type PWM is good,and this topology is often used in bidirectional DC/AC converters.In the establishment of the mathematical model,it can be completed on the basis of the abc coordinate system based on the above-mentioned theory,and in addition,it can also be completed on the basis of the dq coordinate system.Model the system through different coordinate systems and analyze the realization of three-phase rectifier control.(3)Considering various working conditions such as photovoltaic output fluctuation,energy storage battery charge and discharge management,and load increase and decrease,carry out research on different modes of energy storage converter(PCS)work.Aiming at the energy management strategy,based on the DC bus voltage fluctuation as the basis for energy layer adjustment,a power balance control based on rule logic control is proposed.Finally,the established simulation model needs to be verified on the test platform.According to the test,the following conclusions can be drawn: the control strategy proposed by the system can realize the bidirectional flow of energy in the network and maintain the system’s balanced and stable power state;at the same time,the DC bus voltage will not fluctuate;and the use of decommissioned power batteries to achieve smooth power output fill the valley with peak cutting.Compared with the DC bus voltage level energy management,it further improves the power tracking accuracy,thereby reducing energy loss.