Research On Grid-connected Control Technology Of Photovoltaic Power Generation System

For a long time,the fossil energy as the main form of energy utilization provided the driving force of development of productive forces,but the fossil energy reserve is limited and environment pollution problem is increasingly attracting the attention of the people all over the world,so all kinds of new forms energy are widely used,Photovoltaic technology as a green clean energy has become the focus of new energy utilization,especially the application of grid-connected photovoltaic(pv)technology as its main form.Therefore,this thesis studies related technologies of grid-connected control of photovoltaic power generation,especially maximum power point tracking technology and inverter control technology.The main contents are as follows:First of all,Analysis the working principle of the photovoltaic effect and the structure of photovoltaic cell,establishing the model of photovoltaic cells and simulation through the Simulink module of MATLAB software.The volt-ampere characteristic curves of pv cel ls are obtained under different environmental conditions,analyses the influence of changing temperature and light intensity on photovoltaic power generation.The requirements of grid-connected control strategy are analyzed based on the design of photovoltaic power station After confirming the structure of photovoltaic inverter,And it is confirmed that the two-stage inverter structure is the foundation of the subsequent research on grid-connected control strategy.Secondly,Study The MPPT control strategy of photovoltaic power generation system and its improvement,Select the Boost circui t as DC-DC conversion unit main circuit after analysis the control circuit.Then study the maximum power point tracking technology(MPPT),After introduce Several common MPPT control methods,A new MPPT control strategy is proposed,The simulation results show that it meets the design requirementsFinally,On the basis of the analysis of common inverter control methods,A double closed loop quasi-PR control strategy with feedback is proposed,Modulation control is carried out through SVPWM and then get the grid-connected current.Through the simulation,The feasibility and effectiveness of this method are verified.