Research On Multi-objective Control Strategy Of Photovoltaic Grid-connected Inverter

Photovoltaic power generation makes solar energy widely used.The grid-connected photovoltaic inverter connecting photovoltaic array and grid is the key of the whole photovoltaic power generation system.Therefore,focusing on the control strategy of grid-connected photovoltaic inverters,this paper makes the following research for the control purposes of reactive power compensation,unbalanced current compensation and harmonic suppression.This paper introduces the research background and significance of photovoltaic power generation,the research status of photovoltaic grid-connected inverters at home and abroad,analyses the topology and mathematical model of three-phase full bridge voltage source inverters,and deeply analyses an improved conductivity incremental MPPT control strategy for power compensation of photovoltaic grid-connected inverters.It is concluded that the maximum power can be achieved when the illumination intensity changes.Tracking control of rate point.A PI-QPR composite control strategy based on radial basis function is proposed.This strategy controls the inner current loop in the power and current double-loop control system.The adaptive learning ability of RBF neural network can adjust three parameters of QPR controller online by automatically adjusting the weights of each neuron,so as to achieve the optimal value suitable for the current state and improve the power quality.Through the simulation of MATLAB/Simulink platform,the results show that the method realizes the current tracking without static error,reduces the total harmonic distortion rate of output current,improves the anti-interference ability of the system.A multi-objective control strategy for three-phase grid-connected inverters is proposed,which realizes the simultaneous control of harmonic,reactive power fluctuation and three-phase current imbalance.An ip-iq current detection method based on instantaneous reactive power theory is adopted,which can detect the compensated current.In order to reduce the measurement error of phase-locked loop,a softwarephase-locked loop based on decoupled double synchronous reference coordinate transformation is introduced,and the multi-objective control principle of three-phase grid-connected inverter is given.The correctness and feasibility of the strategy are verified by simulation on MATLAB/Simulink platform.