PROJECT TITLE :

Front-End Isolated Quasi-Z-Source DC-DCConverter Modules in Series for Photovoltaic High-Voltage DC Applications - 2016

ABSTRACT:

A quasi-Z-supply modular cascaded converter (qZS-MCC) is proposed for high-voltage (HV) dc integration of photovoltaic (PV) power. The qZS-MCC contains front-finish isolated qZS half-bridge (HB) dc-dc converter submodules (SMs) in series. By the qZS-HB handling PV voltage and power variations, a unified duty cycle is applicable for the front-finish isolation converter of all SMs. Resultantly, the proposed system improves the quasi-Z-source cascaded multilevel inverter and also the modular multilevel converter based PV counterparts in terms of no double-line-frequency pulsating power thus on low qZS impedance, HV dc collection of PV power thus to scale back conversion stages for dc transmission, and overcoming the limit of series-output voltage with easy galvanic isolation. Operating principle and power loss analysis of the qZS-MCC are presented. Parameter style guidelines and simulation are addressed based on a 60-kW SM; experimental results are administered on a downscaled prototype as a proof-of-concept, demonstrating the validity of the proposed system.