MULTIPHASE QUASI-Z-SOURCE DC-DC CONVERTERS FOR RESIDENTIAL DISTRIBUTED GENERATION SYSTEMS

Abstract

A multiphase quasi-Z-source (qZS) dc-dc converter was proposed for the distributed energy generation applications. It contains single-switch qZS isolated dc-dc cells with voltage doubler rectifier. These cells are connected in parallel at the input side and in series at the output side to increase the dc voltage gain. A dc voltage blocking capacitor in series with the isolation transformer results in resonance that could be utilized for soft-switching. Two design approaches were proposed: considering phase shedding dependent on the input voltage and without it. The former targets wide input voltage range applications, while the latter suits better for the high input current applications. Experimental prototype rated for 300 W was tested with two types of isolation transformers designed according to the two presented approaches. It could be used as PV module integrated converter with wide input voltage regulation range. The experimental results prove efficiency improvement from the phase shedding. Resonance frequency variations caused by utilization of the multilayer ceramic capacitors and their possible influence on switching losses are discussed.

Existing System

In the existing system high gain dc-dc converters capable of integration of LV energy sources into a dc bus of much higher voltage is used.

Proposed System

In the proposed system does not introduce the topology of the basic cell. Instead, it proclaims this topology as a universal power electronics building block useful for the modern application where high voltage step-up or (and) high input current are required. Moreover, this study provides a closed-form solution for the input current ripple calculated of the cascaded multiphase ISC based on the IPOS multiphase architecture, as well as it introduces concept of the phase shedding for this system. The IPOS multiphase energy conversion system was proposed and presents operating principle of the basic cell. The benefits of the interleaved control for the given IPOS multiphase system based on the quasi-Z-source (qZS) network was studied.

Architecture

Indoor dc microgrid for households of the future featuring high voltage and low voltage dc buses

IPOS multiphase ISC based on the single-switch topology.