Quasi-Z-source based bidirectional DC-DC converter and its control strategy

Abstract

This paper presents a quasi-Z-source based isolated bidirectional DC-DC converter (qZIBDC) for renewable energy applications. The converter utilizes a dual active bridge circuit with a quasi-Z-source network on both sides, so the converter works as buck/boost converter from either side. It has a wider input/output voltage operating range, soft-switching capabilities without additional devices, and higher boost capability than a traditional dual active bridge circuit. Apart from that, shoot-through states are incorporated in its operating cycle to boost the input voltage resulting in high reliability of the proposed converter. Due to the symmetrical structure of the circuit, there is no defined high voltage or low voltage side as in traditional isolated bidirectional DC-DC converter. The operating principle and control strategy of the proposed converter are presented. Simulation and experimental results are provided to verify the effectiveness of the proposed converter topology and its control strategy.

Review of low carrier ratio converter system

“…Its unique impedance source network and the matching of the inverter bridge arm are equivalent to a straight state, which makes it possible to increase the equivalent switching frequency of the system. Moreover, the impedance source inverter is more reliable [24][25][26][27] .…”

“…The impedance source converter topologies mentioned in Refs. [24][25][26][27] generally increase the degree of freedom of the system by adding a passive network.…”

Quasi‐Z‐source‐based bidirectionalDC‐DCconverters for renewable energy applications

“…A qZS based high step‐up DC‐DC converter has been presented in Reference 29 for improved voltage gain. In Reference 30, a qZS based bidirectional DC‐DC converter with symmetric structure is presented, however the active and passive component count is high increasing the cost. The qZS features low inrush current, lower component count, high control flexibility, and continuous DC input current 31,32 …”

Hourglass‐shaped impedance network based nonelectrolytic capacitors high step‐up converter with low voltage stress

“…For example, fuel cells and solar photovoltaic (PV) devices produce low voltages (lower than 50 V), which is too low to connect with the electric grid or supply residential loads. To solve this problem, a large number of DC‐DC boost converters have been proposed 1‐5 . The topologies of step‐up converters can be divided in nonisolated and isolated, 6 noncoupled‐inductor and coupled‐inductor converters, 7 which have been extensively investigated in the past few decades.…”