Study On Technology Of Grid-connected Solar Cell-super Capacitor Integration Based On Model Predictive Control

Solar photovoltaic power generation is an important national strategy to solve fossil energy depletion,air pollution and carbon dioxide emissions.National "Energy Development Strategy Action Plan" requirements,until 2020 non-fossil energy accounted for the proportion of primary energy consumption should reach more than 15%.This technically poses a major challenge to the efficiency,cost and reliability of photovoltaic power generation.In order to solve the security threat of PV power generation,an novel crystalline silicon solar cell-super capacitor integrated component architecture is designed.Based on this architecture,the integrated components are analyzed theoretically from the maximum power Point tracking,super capacitor energy storage system,grid control technology in three aspects of the integrated components made a detailed study.Firstly,study the working principle and characteristics of solar cells and super capacitors,and complete to build the MATLAB simulation model,then analyze output characteristics of the solar cells the curve and working state in different light intensity and different ambient temperature,build super capacitor energy storage system charge and discharge The simulation model lay the foundation for the next step.Secondly,because of the PV system requires the design of the maximum power point tracking(MPPT)of the PV to ensure continuous operation at maximum power point(MPP)and maximize the output power to ensure safe and efficient power generation in dynamic weather conditions.Analyze the principle of three kinds of maximum power point tracking algorithms,and propose a fixed step model predictive control(MPC)technique,which applies the model prediction algorithm to the maximum power point tracking.The maximum power point of a P V system is determined by the use of perturbation and observation techniques.The MPC is characterized by the use of a system model to select the best action.The fixed-step prediction model based on MPPT has the advantages of fast response speed and low power fluctuation in steady state,and the simulation results show the characteristics of the algorithm.Finally,the current droop control scheme and simulation of DC micro grid are studied.Since the droop control method does not require communication between the power supply and the load,the DC/DC converter needs to be used to decouple the source voltage because the operating conditions and maximum power point tracking(MPPT)may vary due to the DC bus voltage.In this paper,a sag current regulator based on model predictive control is proposed for DC/DC converters in DC power distribution systems by controlling the input current of the PV system and super capacitor and the droop characteristics of the output current injected into the DC bus.Measure the input voltage,the output voltage,the inductor current,and the reference current generated by the down controller,and then apply the prediction equation.In this design,consider the traditional boost converter to optimize the controller to determine the operating state.For super capacitors,when the bus voltage begins to increase,the controller is instructed to start charging the battery to absorb excess power.In the case of a bus voltage drop,the controller super capacitor releases energy to compensate for the power.