Power Optimization And Grid-connection Of Power Generating System With PV Module Integrated Converters

Based on the understanding of the domestic and international research situation of photovoltaic power generation system in recent years,this paper chooses the DC module power generation system as the research object.The traditional single-peak MPPT method and multi-peak MPPT method which adapt to different characteristic curves are introduced.The structure and DC/DC topology of the common PV system are contrasted.PV module integrated converters(MICs)is adopted,which adopts Buck-Boost topology.In this paper,The output power-voltage characteristics of photovoltaic array are discussed.A para-curve predictive power close-loop maximum power point tracking(MPPT)method is proposed.By quadratic fitting,the actual power value at the stationary point of the fitting function is considered to predict and revise the position of maximum power point.Initial points are chosen reasonably to speed up MPPT.Schematics of photovoltaic cont:rol system with MPPT are presented,and the algorithm proposed is implemented in experimental prototype,which proved the feasibility and effectiveness of the scheme.To solve the deficiency that is disadvantage of global optimization ability and easy to trap in one of the local extreme power points,which is caused by traditional maximum power point tracking(MPPT)methods,this paper proposes a novel MPPT method using quantum-behaved particle swarm optimization(QPSO)algorithm.This algorithm adopts detect-search strategy based on voltage closed-loop control,making voltage particles search on photovoltaic characteristic curves in quantum-behaved paths.By setting a modulation strategy of separation and reunion factor and stopping criterion,this study improves the precision of stable state tracking of the QPSO algorithm used in PV system,and also eliminates power oscillation under stability conditions.Experimental results show that QPSO algorithm has good performance with less parameters,superior global optimizat:ion ability,favorable stability and better adaptability compared with traditional particle swarm optimization(PSO)algorithm in PV MPPT.The power-bus voltage output characteristic curve of the PV MICs series system is studied.The bus-voltage maximum power optimization control is carried out for the multi-peak curve of the curve.The PSO algorithm and QPSO algorithm are used to realize the bus voltage optimization.The experiment platform of photovoltaic module grid-connected system is set up,and the experiment of grid-connected system of the PV MICs series is carried out.