Research On The Photovoltaic Grid-connected Current-source Inverter

Solar energy, which is abundant, easier to obtain and non-pollution etc, has a broadapplication prospect in photovoltaic power generation system. In traditional photovoltaicgrid-connected power generation system, voltage source inverter which needs extravoltage-boost link to achieve grid-connected criterion, is more used, not only increasingthe power dissipation but also making the circiut structure more complex. However, thecurrent source inverters feature voltage-rise itself, which can both realize the maximumpower point tracking and grid-connected criterion.This paper focuses on the single-phase current source inverter. The main contents areas follows:The superiority of the single-phase CSI in the PV sytem application is analyzed, itssmall signal mathematical model is founded, and the modulation strategy are alsointroduced, which provide theoretical basis for the studying and design of the controlsystem. In the single-phase CSI grid system the typical PI regulators are used to obtaingood control performance.The AC side of current source inverter has the defect of transient oscillation. Thispaper introduces the LQ optimal control to eliminate the effect of this phenomenon, and inorder to achieve objective of optimal control, genetic algorithm is applied to designweighting matrix. The paper also researches the output characteristics of photovoltaic cellsand maximum power point tracking algorithms, the single-phase current source inverter isapplied to photovoltaic grid-connected system to make the output of photovoltaic systemmeet grid-connected criterion.And then, the hardware circuit and software of the system are designed. Based ontheoretical analysis’s foundation, a set of photovoltaic grid-connected experimentalprototype has been built, which indicates the feasibility and effectiveness of this method.