| The development and utilization of renewable energy represents that the human has entered a new era of energy and reverses the traditional pattern of energy consumption mainly on fossil energy gradually.But at the same time,the development of the renewable energy in the grid power is constrained because of its randomness and intermittent.The proposing of energy storage technology make up the defects of the renewable energy in the grid power primely and play an irreplaceable role.That the energy storage system consisted of energy storage medium,energy storage converter and control system is configured in the power supply side could smooth renewable energy power generation output fluctuation on different time scales and improve power grid scheduling, predictability and efficiency.The research work is expanded from two aspects in this paper by studying relevant literature about energy storage technology in the application of renewable energy power generation:Firstly, the topology and control strategy of energy storage converter are discussed in this paper, and a two stage energy storage converter is introduced. Front-stage bi-directional DC-DC converter use non-isolated bidirectional half bridge topology. Based on the analysis of the circuit in two different working modes, this paper designs and verifies parameters of the main circuit in accordance with the requirements of inductance and capacitance current ripple. A small signal model is established for the circuit in two operating modes. Voltage/current closed loop controller is designed to ensure the constant voltage/current charging status of the super capacitor. Back-stage adopts the two level three phase three wire converter structure, the mathematical model of the topology is established. The closed loop control model of the circuit under the condition of unit power factor is derived. Combining with the three-phase synchronous phase locked loop algorithm and SVPWM algorithm, the voltage/current closed-loop controller is designed to realize the unit power factor control.Then, this paper researches on the application of the two stage energy storage converter in Photovoltaic power generation. A general photovoltaic cell engineering model is introduced to simulate input and output characteristics under different environmental conditions. An algorithm based on maximum power point tracking named Perturbation and Observation is introduced to ensure pv module output efficiency. In order to solve the problem of the photovoltaic power fluctuations, this paper puts forward a lead-acid batteries and super capacitors hybrid energy storage scheme based on PQ control stragety that uses low pass filter algorithm to estimate the energy compensation for energy storage system.Finally, a model for hybrid energy storage system under the background of grid-connected photovoltaic cell is set up in Matlab/Simulink platform. The simulation verifies the feasibility and correctness of the proposed scheme. |
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