Calculation of power and efficiency.

The design of a power electronic interface for high voltage difference DC buses is a key aspect in DC microgrid applications. A multi-port non isolated interleaved high-voltage gain bidirectional converter, which facilitates bidirectional power transfer and islanded operation in a DC microgrid, is presented in this paper. The forward high-voltage transfer ratio is achieved using a voltage multiplier circuit, and the high-gain step-down power conversion is performed using a resonant power module. A novel power transfer selection algorithm is proposed to control power flow among the interfaces of the RES, ESS, and DC grid converters, which utilizes the net power difference as the basis for switching the converter. The proposed converter is simulated for a 24 V PV source, 12 V battery, and 400 V DC grid interface using MATLAB/SIMULINK. A 200 W hardware prototype is implemented. The simulation results for voltages, currents, and power flow among RES, ESS, and microgrid DC bus proved an excellent voltage regulation, efficient power conversion, and a feasible duty cycle range with high voltage gain. These observations are validated through equivalent experimental results. A comparison is made regarding achieved gain, component sizing, achievable power transfer modes, efficiency, and control complexity with existing converters for DC microgrid applications. The presented topology proved to be a better interface with multiple-mode support with high efficiency.

面向高压差直流母线的电力电子接口设计，是直流微电网应用中的核心环节。本文提出了一种多端口非隔离交错式高增益双向变换器，可实现直流微电网内的双向功率传输与孤岛运行。该变换器通过电压倍增电路实现正向高压传输比，并借助谐振功率模块完成高增益降压功率变换。本文提出了一种新型功率传输选择算法，以净功率差作为变换器切换的依据，用于调控可再生能源系统（Renewable Energy Source, RES）、储能系统（Energy Storage System, ESS）与直流电网变换器接口间的功率流。本文基于MATLAB/SIMULINK平台，针对24 V光伏电源、12 V蓄电池及400 V直流电网接口场景对所提变换器进行了仿真建模，同时搭建了200 W的硬件原型样机。针对光伏电源、储能系统与微电网直流母线间的电压、电流及功率流的仿真结果表明，该变换器具备优异的电压调节性能、高效的功率变换能力，且在实现高电压增益的同时拥有可行的占空比调节范围。上述结论通过对等的实验结果得到了验证。本文还针对直流微电网应用场景下现有变换器的实现增益、元件选型、可支持的功率传输模式、变换效率及控制复杂度进行了对比分析。结果表明，所提出的拓扑结构具备多模式运行能力且变换效率更优，是一种性能更优异的接口方案。