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2.2 ELECTRICAL, ELECTRONIC, INFORMATION ENGINEERING
Due to a substantial shortage of conventional energy sources, the utilization of renewable energy is gaining attention. Power converters form interfaces to provide power from renewable energy sources to end user systems. Impedance-source inverters (ZSIs) have become a research hotspot and are widely used to overcome the drawbacks of conventional voltage-source inverters and current-source inverters such as two-stage power conversion and less immunity to electromagnetic interference noises. This paper presents various transformer-based ZSIs mainly classified as trans-ZSIs, improved trans-ZSIs, inductor-capacitor-capacitor transformer ZSI, TZSIs, and their comparisons with a new family of ZSIs called Γ-Z-source inverters (ΓZSI). Full operational analysis of an improved ΓZSI with the clamping diode D2 and its benefits over the conventional ΓZSI are also discussed. The improved ΓZSI utilizes a higher modulation index and consequently a lower duty cycle to achieve same gain, thus reducing the switch voltage stress and providing better output quality. Additionally, an extra diode provides voltage clamping to the dc-link voltage to limit voltage overshoots. The comparative evaluations of all the above mentioned ZSIs are presented in the literature and to validate the advantages of the improved ΓZSI, simulations, and experimental comparisons are also performed.
Z. Aleem and M. Hanif, "Operational Analysis of Improved Γ-Z-Source Inverter With Clamping Diode and Its Comparative Evaluation," in IEEE Transactions on Industrial Electronics, vol. 64, no. 12, pp. 9191-9200, Dec. 2017, doi: 10.1109/TIE.2017.2708358.