Research For PV Grid-Connected Inverter

For the strenuous energy sources currently in the global scope,exploiting and utilizing the solar energy is paid more attention by many people than before. Photovoltaic(PV) generation,one important method of using solar energy,is very promising.Under this background,the dissertation deeply researches the PV grid-connected inverter,which is the hard core of the system.The paper analyzed the topology of the inverter,maximum power point tracing(MPPT),the control method of the inverter and the technology of grid-connected such as anti-island.Firstly,it briefly introduces the present situation and the development prospects of Photovoltaic generating at home and abroad.Based on the character of single-phase PV grid-connected system,the paper expatiated a suitable topological construction,which doesn't use the transformer with features which the small size, low cost and easy control strategy and so on.Secondly,by comparing many different traditional methods,this paper finds a new way to use a new Fibonacci search algorithm to realize the maximum power point tracking(MPPT).In this thesis,it is demonstrated theoretically that the maximum power-output can be matched by adjusting the duty ratio of the DC/DC circuit.This paper presents the needed of anti-islanding effect,analyses the active and passive detecting methods separately,then verifies the validity of the active frequency drift with periodical disturbance and positive feedback method.Finally,several popular control methods of inverter are simply analyzed.Based on SPWM,the scheme of current control have some advantages,such as invariable switching frequency,simplify signification,and easy realized.In the end,the resultants of the simulation using MATLAB proved the feasibility and validity.