Research Of Three Phase Photovoltaic Generation System Based On Three-level Inverter

In March2011, a magnitude9earthquake in Japan has been caused the damagedfukushima daiichi nuclear power plant leak, which has been attached the highattention all over the world. Solar photovoltaic power generation is the mostimportant renewable energy development potential, as China’s strategic new industrystatus will not change. On March1,2012, the state launched to allow new energypower generation units and individuals to sell to national policy. Family photovoltaic(PV) power plant with its lower costs, green environmental protection, savinginstallation space, etc. it has been became the main force of China’s family electricityproduction. The state grid corporation in2011after launch distributed photovoltaicsupport poliecy, small photovoltaic industry in our country began to blossom gloriousin the field of new energy. Based on the three-phase PV power generation system asthe research object, the output characteristics of PV cells, PV maximum power pointtracking control technology inverter control strategy has been studied.Firstly, the output characteristics of photovoltaic cells, and photovoltaic cellsunder standard test conditions for engineering calculation were analyzed in this article.On the basis of mathematical model, a kind of model based on the calculation modelof the photovoltaic cell engineering general working condition was built, and has beencarried on the simulation in Matlab/Simulink, and was verified its correctness.And then, in the analysis of photovoltaic cells based on the principle ofmaximum power point tracking, the existing fixed-point voltage,short circuit currentratio coefficient,differenttiacl calculation method,perturbation of observation,INC,fuzzy, artificial neural network,intelligient complex legal method,PSO MPPT controlalgorithm and implementation of the basic topological structure of MPPT controlcircuit were summarized. According to the actual need in engineering, the disturbanceobservation as main research object was selected, in view of the traditionalperturbation in the observation method of perturbation and misjudgment phenomenon,a new MPPT controller was designed. The controller was combined with themisjudgment of adaptive variable step size perturbation observation algorithm, a newtype of Buck-Boost dual PWM control circuit, and integral saturation controllerclosed loop control were inhibited. And through the simulation model of theexperimental data were compared with other MPPT controller sets, the betterperformance of the controller were verified. Then, in NPC,capacitance of the clamping,mixed clamping,universal,cascading,cascading multilevel inverter topology, the feature of photovoltaic power generationsystems was combined with the advantages and disadvantages of the chosen typediode clamping three-level inverter for photovoltaic inverter system has beencompared in this paper. Analysis of three level inverter PWM control strategy, theSVPWM control strategy and several advanced SVPWM control strategy on the basisof traditional SVPWM control algorithm in the inverter of high level for complex, thedisadvantages of the slow control speed, a reduced order model SVWM controlalgorithm was proposed to simplify operations and improve the speed. Throughsoftware simulation and small power physical experiments to the three-level inverterand the good performance of SVPWM control algorithm was verified, as the validityand feasibility of the reduced order type SVPWM control strategy.Finally, abased on all above,a kind of independent model in the simulation modelof three-phase photovoltaic system was designed in this paper.Then on the basis ofthe model, by adding a parallel controller with a filter a simulation model ofthree-phase grid type photovoltaic power generation system was built. Through theanalysis of the experimental waveform and argument, and once again confirmed thatthe above design idea was practical.