Improvement of Z-source and Quasi-z Source Inverter for Photovoltaic Applications

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Aseyedali, Mahdi | 2021

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Type of Document: M.Sc. Thesis
Language: Farsi
Document No: 53719 (05)
University: Sharif University of Technology
Department: Electrical Engineering
Advisor(s): Parniani, Mostafa
Abstract:
The Z-source and quasi-Z source inverter have a capability to increase and decrease the output voltage without using extra switching stages or transformer. Therefor these inverters are an excellent choice for applications such as photovoltaic sources because of their higher efficiency, higher reliability and lower volume and cost. One drawback of these inverters is the leakage current that causes undesirable effect on the power system and safety issues. In this research we are going to develop a new modulation method for these inverters to reject the leakage current. In this method the harmonic content of common mode voltage is concentrated on the switching frequency and its harmonics while reducing the amplitude of the second and third harmonic. Consequently the leakage current can be rejected up to 90% by using only a small notch filter tuned on the switching frequency. The other advantages of this method are that the THD and percentage of leakage current rejection are nearly constant over different modulation indices
Keywords:
Quasi-Z-Source Inverter ; Total Harmonic Distortion ; Pulse Width Modulation (PWM) ; Leakage Current ; Common Mode Voltage ; Z-Source Inverter ; Notch Filter

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