Study on MVDC Grid-connected Scheme Based on Modular LLC Resonant Converters for Photovoltaic Energy

doi:10.3969/j.issn.1000-7229.2018.10.006

Abstract

Abstract: Different from traditional forms large-scale photovoltaic energy integrates into AC network or low-voltage DC grid, photovoltaic power generation connected to MVDC distribution system has some advantages, such as large capacity, higher efficiency, voltage stability and power quality. It is an energy pooling technology needed for the development of DC distribution network in the future. Firstly, a scheme for medium or large capacity photovoltaic power generation system to access DC distribution network is proposed and a topology of the system is designed. Through analysis on the characteristics of photovoltaic cells and the operating characteristics of sub-modules, a new control strategy for modular LLC converter is designed as well as the parameters of generating units and sub-modules. The control system achieves voltage and current sharing and realizes the maximum power tracking of the photovoltaic unit. Finally, the feasibility of the proposed scheme and control system are verified by simulation.

Key words: DC distribution network, LLC resonant converter, DC grid-connected photovoltaic power system, control system

CLC Number:

TM 615

CHEN Jiaxi，JIANG Daozhuo，ZHANG Chong，HU Liexiang，LU Li. Study on MVDC Grid-connected Scheme Based on Modular LLC Resonant Converters for Photovoltaic Energy[J]. Electric Power Construction, 2018, 39(10): 44-53.

References

［1］贾科，顾晨杰，毕天姝，等.大型光伏电站汇集系统的故障特性及其线路保护［J］.电工技术学报，2017，32（9）：189-198.

JIA Ke，GU Chenjie，BI Tianshu，et al.Fault characteristics and line protection within the collection system of a large-scale photovoltaic power plant［J］.Transactions of China Electrotechnical Society，2017，32（9）：189-98.

［2］江道灼，郑欢.直流配电网研究现状与展望［J］.电力系统自动化，2012，36（8）：98-104.

JIANG Daozhuo，ZHENG Huan.Research status and developing prospect of DC distribution network［J］.Automation of Electric Power Systems，2012，36（8）：98-104.

［3］杜翼，江道灼，尹瑞，等.直流配电网拓扑结构及控制策略［J］.电力自动化设备，2015，35（1）：139-145.

DU Yi，JIANG Daozhuo，YIN Rui，et al.Topological structure and control strategy of DC distribution network［J］.Electric Power Automation Equipment，2015，35（1）：139-145.

［4］SHADMAND M，BALOG R，ABURUB H.Model predictive control of PV sources in smart DC distribution system: Maximum power point tracking and droop control［J］.IEEE Transactions on Energy Conversion，2014，29（4）：913-921.

［5］FLETCHER S，NORMAN P，FONG K，et al.High-speed differential protection for smart DC distribution system［J］.IEEE Transactions on Smart Grid，2014，5（5）：2610-2617.

［6］ABDELSALAM A，MASSOUD A，AHMED S，et al.High-performance adaptive perturb and observe MPPT for photovoltaic-based microgrids［J］.IEEE Transactions on Power Electronics，2011，26（4）：1010-1021.

［7］SALOMONSSON D，SANNINO A.Low-voltage DC distribution system for commercial power systems with sensitive electronic loads［J］.IEEE Transactions on Power Delivery，2007，22（3）：1620-1627.

［8］BRATCU A，MUNTEANU L，BACHA S，et al.Cascaded DC-DC converter photovoltaic systems：Power optimization issues［J］.IEEE Transactions on Industrial Electronics，2010，58（2）：403-411.

［9］PILAWA R，PERREAULT D.Submodule integrated distributed maximum power pint tracking for solar photovoltaic applications［J］.IEEE Transactions on Power Electronics，2012，28（6）：2957-2967.

［10］WANG Y，HOLLIDAY D，WILLIAMS B.Parallel-connected D-MPPT architecture PV systems with partial power processing converters［C］//Proceedings of IET Conference on Power Electronic Machines and Drives（PEMD 2018）. England：IET，2018.

［11］CAO G，GUO Z，WANG Y，et al.A DC-DC conversion system for high power HVDC-Connected photovoltaic power system［C］//Proceedings of Electrical Machines and Systems（ICEMS 2017）. Australia：IEEE，2017.

［12］史海旭，孙凯，肖曦，等.面向中压直流配电网的光伏发电接入技术综述与分析［J］.分布式能源，2016，1（3）：1-9.

SHI Haixu，SUN Kai，XIAO Xi，et al.An overview and analysis of photovoltaic power integration technology for medium voltage DC distribution network［J］.Distributed Energy，2016，1（3）：1-9.

［13］尹瑞，江道灼，唐伟佳，等.基于模块化隔离型DC/DC变换器的海上直流风电场并网方案［J］.电力系统自动化，2016，40（17）：190-196.

YIN Rui，JIANG Daozhuo，TANG Weijia，et al.Modular isolated DC/DC converter based grid-connection scheme for offshore DC wind farm［J］.Automation of Electric Power Systems，2016，40（17）：190-196.

［14］甘家梁，李志敏，谈怀江.光伏电池输出特性与最大功率点跟踪的仿真分析［J］.电子设计工程，2012，20（14）：98-101.

GAN Jialiang，LI Zhimin，TAN Huaijiang.Simulation research of output features and the maximum power point tracking of photovoltaic cell［J］.Electronic Design Engineering，2012，20（14）：98-101.

［15］Fairchild Semiconductor. Resonant converter design using FSFR-series Fairchild power switch（FPSTM）［R］. Application Note AN-4151，2007.

［16］CHEN W，RUAN X，YAN H，et al.DC/DC conversion system consist of multiple converter modules：Stability, control and experimental verifications［J］.IEEE Transactions on Power Electronics，2009，24（6）：1463-1474.

[1]	WANG Liang, GAI Zhengyu, JIANG Weiyong, SHI Yuxin, MENG Qingmeng. Blocking Strategy for ±800 kV Yan-Huai UHVDC System in Island Operation Mode of Delivering Side [J]. ELECTRIC POWER CONSTRUCTION, 2020, 41(8): 40-47.
[2]	ZHANG Zhirong， QIU Xiaoyan， SUN Xu， REN Hao， ZHANG Mingke. Economic Optimal Scheduling of AC/DC Distribution Network Coordinating Flexible Load and Energy Storage Systems#br# [J]. Electric Power Construction, 2020, 41(5): 116-123.
[3]	HAN Jun， YUAN Dong， XIE Zhenjian， HE Jinwei， LIU Liguo， DU Jian， CAI Chao. Comparison of Typical Configuration Characteristics and Application Mode of AC/DC Hybrid Distribution Network [J]. Electric Power Construction, 2020, 41(3): 93-99.
[4]	SHEN Weidong， FU Shouqiang， LI Hongjian1， ZHAO Guoliang3， GAO Yang. System Design of AC and DC Distribution Network Based on Flexible Substation#br# [J]. Electric Power Construction, 2020, 41(3): 100-109.
[5]	LIAO Hongtu， HUANG Yihong， SHI Yizhi， CHEN Jian. A Bi-Level Two-Stage Robust Optimal Operation Strategy for AC and DC Distribution Network with Photovoltaic and Energy Storage [J]. Electric Power Construction, 2020, 41(3): 110-118.
[6]	SONG Jie， HOU Jibiao. Voltage Regulation Using Compressed-Air Energy Storage System in DC Distribution Network [J]. Electric Power Construction, 2019, 40(6): 49-56.
[7]	RUI Songhua， LIU Haixuan， WANG Hongbo， YIN Deyang， MEI Fei. DG Planning Method for AC/DC Distribution Network Using Genetic-Ant Colony Algorithm [J]. Electric Power Construction, 2019, 40(4): 9-17.
[8]	FU Shouqiang， CHEN Xiangyu， WANG Chang， YANG Lin. Day-Ahead Optimal Scheduling of AC /DC Hybrid Distributed Energy System with Multi-Power Electronic Transformer Adopting Chance-Constrained Programming [J]. Electric Power Construction, 2019, 40(12): 96-103.
[9]	FAN Shixiong, LIU Xingwei, WEI Zechen, GAO Yunxing, WANG Chen. Research on Multi-Time-Scale Control System of DC Distribution Network [J]. Electric Power Construction, 2018, 39(9): 54-60.
[10]	XU Yutao, TAN Zhukui, XIE Baiming, HUANG Hui, LU Qiansu1 BAN Guobang, YUAN Xufeng. Research on Intelligent Protection Configuration Based on DC Breakers for Multi-terminal Flexible DC Distribution Network [J]. Electric Power Construction, 2018, 39(9): 61-69.
[11]	MENG Ming,ZHU Guolin, WEI Yi. Research on Hierarchical Control in AC/DC Distribution Network on the Basis of Optimal Power Flow [J]. Electric Power Construction, 2018, 39(8): 94-101.
[12]	LI Gang, TIAN Jie,LU Yu,LI Haiying,LU Yi,QIU Defeng. Zero-sequence Voltage-suppressing control strategy for MMC-MVDC Without Coupling Transformer [J]. Electric Power Construction, 2018, 39(7): 57-63.
[13]	FU Shouqiang, GAO Yang, CHEN Xiangyu, LI Hongjian, QI Huanhuan, XU Pengliang, XU Wenxiu . Research and Project Practice on AC and DC Distribution Network Based on Flexible Substations [J]. Electric Power Construction, 2018, 39(5): 46-.
[14]	ZENG Ming1，SHU Tong1，LI Ran1，WU Geng1， SONG Wei1，WANG Haojing2，SUN Chenjun3 . Key Problems and Prospects of Transactive Energy Implementation Under Energy Internet [J]. Electric Power Construction, 2018, 39(2): 1-.
[15]	JIANG Shigong, WU Zhili, LI Hongjun, WANG Yunfei, ZHENG Hao. Voltage Stage and Load Distance for DC Distribution Network [J]. Electric Power Construction, 2017, 38(6): 59-.