Design Of Grid-connected PV System Based On Improved Z Source Inverter

Traditional fuel is reducing every day, which do harm to our living environmentand cause regional conflicts. In order to adapt to the requirements of sustainabledevelopment, developing renewable energy vigorously has become the only way ofhuman’s development. Solar energy is inexhaustible, clean and pollution-free. Thesecharacteristics attract most nations’ attention and development. Now, the applicationsof solar energy have been developing vigorously.Grid-connected PV is a better way of solar energy’s using. PV inverter plays avital role in the inverter process of energy conversion. Upper and lower bridge arm ofthe conventional inverter exist the possibility of shoot-through, which low reliabilityof the inverter. In order to prevent the shoot-through station, dead time is introducedinto the PWM. Which causes the dropping of power quality. In order to overcome thedefects of traditional inverter, the article uses the Z-source inverter. The paperanalyzes the structure and working theory of the traditional Z-source inverter, andexplains its’ the strengths and weaknesses. To this end, the article uses a kind ofimproved Z-source inverter, which makes up the deficiencies of the traditionalZ-source inverter. We model the improved Z-source inverter with state spaceaveraging method. At the same time, the article summarizes suitable PWMmodulation strategy for the Z-source inverter, and analysis boost capacity, modulationrange of every PWM modulation strategy. The article designs the control system andintroduces the current control strategy based on fluctuations of capacitor voltage anddropped PLL.The simulation results verify that the proposed method is effective and theoryanalysis is right. What’s more, the article designed a feasible plan for the improvedZ-source inverter.