Research Of Grid-connected Inverter Technology Based On Direct Current Control

After entering the21st century, human society is facing a shortage of fossil fuelsand ecosystem environmental pollution problems. The age of cheap oil is over, gradualchanging of energy consumption structure, devoting major efforts to developingrenewable sources of energy and taking the road of sustainable development hasbecome the consensus of the Governments of the world. So, those energy which isclean, pollution-free and huge storage such as solar, wind, hydro and other renewableenergy development is received widespread attention. One most utilization of solarenergy is the photovoltaic generation. Developing along with the advanced controltechnology, Solar photovoltaic generation is from only in remote areas and the specialoccasions for electricity use to urban grid-connected systems and large-scale PV powerstation.For grid-connected Inverter, there are two control methods, one is direct currentcontrol and the other is indirect current control. The controlled member of directcurrent control is inductance current, and the controlled member of indirect current isthe voltage peak-to-peak value and phase of output. The peak-to-peak value and phasemutual coupling of voltage outputs. Therefore, Comparing the direct current controland the indirect current control, the controlled member of direct current control issimpler.Under this background, the article has conducted the deep research togrid-connected inverter. With the target of output of inverter containing maximumactive power, minimum reactive power and harmonic content, this paper study ongrid-connected solar inverters. Present paper prime task:Firstly, an overview of the research background and significance, as well asdomestic and international PV industry research status.Then, This paper introduces commonly used direct current control strategy. Andusing an improved current hysteresis control method based on traditional currenthysteresis control method based on5kW grid-connected inverter. With simulationunder the simulation software, confirming the feasibility of the improved currenthysteresis control method.Finally, listing program flowchart and some experiment waveform of theimproved current hysteresis control method.