Modular Multiport Voltage Balance Topology Based on Boost Half-Bridge and Quadruple Semiactive Rectifier for MVdc Integration of Distributed PVs

The Input Independent Output Series (IIOS) modular multiport dc-dc converter is renowned for its single stage power conversion and high efficiency. And it is a promising solution for integrating distributed photovoltaics (PVs) into medium-voltage DC (MVDC) distribution networks. The inherent variability of PV input power often leads to output voltage imbalance in IIOS architecture, which can result in power curtailment and device damage. In order to avoid the occurrence of these faultiness, a multi-port self-voltage balance IIOS power converter based on current-source boost half bridge (CS-HB) and quadruple voltage semi-active rectifier (QVSAR) is proposed. The topology is consisted of CS-HB units on PV side, QVSAR units on MVDC grid side, and a series resonant power balance module (SRPBM). SRPBM is used to realize submodule output voltage balance, which has simple control and good dynamic characteristics. In addition, the proposed topology has a small input current ripple, all the switches can realize zero-voltage switching (ZVS), and all the diodes can realize zero-current switching (ZCS), which is conducive to the improvement of system efficiency. Finally, the feasibility of the topology is verified by both simulations and experiments.