A Modular DC/DC Photovoltic Generation System for HVDC Grid Connection

作     者：Guoen Cao Kai Sun Siyue Jiang Shilei Lu Yibo Wang 

作者机构：Institute of Electrical EngineeringChinese Academy of SciencesBeijing 100190China State Key Laboratory of Power SystemsTsinghua UniversityBeijing 100084China 

出 版 物：《Chinese Journal of Electrical Engineering》 (中国电气工程学报（英文）)

年 卷 期：2018年第4卷第2期

页      面：56-64页

学科分类：0808[工学-电气工程] 080802[工学-电力系统及其自动化] 0809[工学-电子科学与技术（可授工学、理学学位）] 08[工学] 0807[工学-动力工程及工程热物理] 0802[工学-机械工程] 0811[工学-控制科学与工程] 

基　　金：Supported by the National Key Research and Development Program“Novel DC-DC Boost Converter Module Based on Wide Bandgap Power Device for HVDC-Connected Photovoltaic Unit”(2016YFB0900205). 

主　　题：Photovoltaic generation DC-DC converter HVDC grid connection cascaded configuration 

摘      要：A modular DC/DC conversion system with distributed MPPT and centralized step-up converter for photovoltaic energy integrated into HVDC grids is proposed in this paper.The conversion system consists of two power stages,with MPPT converter as the first stage and a step-up converter as the second stage.Both stages are modular structures.For the distributed MPPT stage,interleaved boost topology is utilized to effectively reduce the input and output ripples without adding extra components.For the centralized step-up stage,narrow-switching-frequency-variation LLC topology is employed,with the modules being configured as input-parallel-output-series structure.Full-range soft-switching property is achieved in the LLC stage to minimize switching losses.Theoretical analysis is carried out for the system voltage gain and design principles.Simulation and experimental results of a 3kW prototype system are presented to verify the theoretical analysis of the proposed system.