Research on the single-phase single-stage photovoltaic grid-connected current source inverter

Solar energy, which is abundant, easier to obtain and non-pollution etc, has a broad application prospect in photovoltaic power generation system. In traditional photovoltaic grid-connected power generation system, voltage source inverter(VSI) which needs extra voltage-boost link to achieve grid-connected criterion, is more used, not only increasing the power dissipation but also making the circiut structure more complex. However, the current source inverters(CSI) feature voltage-rise itself, which can both realize the maximum power point tracking and grid-connected criterion. This paper focuses on the single-phase current source inverter. Single-Phase current-source PWM grid-connected inverter is established for the research and the linear quadratic(LQ) optimal control method is applied to this inverter, which solved the transient oscillation defect of current source inverter. Through the method combined by computer simulation and experimental study, a laboratory prototype of 400W current source inverter has been implemented and tested. Results of simulation and experiment show that this method can make output AC currents sinusoidal and in phase with grid voltages.