考虑多储能系统功率分配的独立直流微电网协调控制策略

doi:10.12204/j.issn.1000-7229.2021.04.010

摘要/Abstract

摘要：

针对多源储结构的独立直流微电网,提出考虑多储能系统功率分配的独立直流微电网协调控制策略,以实现源储能源利用率最大化与多储能系统间功率合理分配两方面的平衡控制,提升微网持续供电能力。根据直流母线电压信号将微网系统运行划分为5种工作模式,以协调源储运行,保证光伏能源利用率最大化及储能系统出力充足。同时,直流微电网工作模式切换过程中源储控制器保持不变,并根据当前运行状态自动调节自身运行曲线,维持系统功率平衡和母线电压稳定。其中,基于自适应功率控制的光伏系统控制方法根据母线电压自动调节光伏系统运行点追踪或偏离最大功率点,实现最大功率点跟踪(maximum power point tracking ,MPPT)模式与降功率模式间的平滑切换。其次,基于荷电状态(state of charge,SOC)的自适应功率下垂控制器根据储能单元自身SOC调节其下垂曲线,实现系统功率在多储能单元间的动态分配,避免过充过放。最后,通过搭建Matlab /Simulink 仿真模型,验证了所提方法的有效性。

关键词: 直流微电网, 直流母线电压, 下垂控制, 荷电状态(SOC), 功率分配

Abstract:

A coordinated control for islanded DC microgrid considering power sharing of multiple energy storages is proposed to realize the balance control of the energy utilization maximization and the reasonable power sharing among multiple energy storages. The operation of the DC Microgrid is divided into five working modes according to the DC bus voltage. During mode transition, control structure of each unit keeps unchanged, and its droop curve can be adjusted adaptively according to current operating state. The coordinated operation of source and storage maintains the system power balance and bus voltage stability, which maximize the utilization rate of photovoltaic energy and ensures sufficient output of energy storage. Firstly, an adaptive power control strategy is applied to PV converters, which is based on automatic regulate the output power of PV tracking or off the maximum power point according to the DC bus voltage and realizes the smooth switching between maximum power point tracking (MPPT) mode and off-MPPT mode. Secondly, an adaptive droop control strategy based on the state of charge is designed for energy storages, which realizes the reasonable distribution of system power by multiple energy storage units according to their SOC and avoids excessive discharge or depth charge. Finally, the control strategy is verified by simulation with Matlab/Simulink.

Key words: DC microgrid, DC bus voltage, droop control, state of charge (SOC), power distribution

中图分类号:

TM732

王子鹏, 郑丽君, 吕世轩. 考虑多储能系统功率分配的独立直流微电网协调控制策略[J]. 电力建设, 2021, 42(4): 89-96.

WANG Zipeng, ZHENG Lijun, Lü Shixuan. Coordinated Control for Islanded DC Microgrid Considering Power Sharing of Multiple Energy Storages[J]. ELECTRIC POWER CONSTRUCTION, 2021, 42(4): 89-96.

图/表 11

图1 独立直流微电网结构

Fig.1 Configuration of DC microgrid

图2 不同模式下独立直流微电网控制策略

Fig.2 Control strategy of DC microgrid underdifferent modes

图3 光伏发电单元控制框图

Fig.3 Control block diagram of PV unit

图4 降功率运行点示意图

Fig.4 Off-MPPT operating points

图5 功率控制流程图

Fig.5 Flow chart of power control

图6 储能单元控制框图

Fig.6 Control block diagram of energy storage

图7 储能单元功率分配

Fig.7 Schematic diagram of power distribution of energy storage units

表1 直流微电网系统参数

Table 1 System parameters of the DC microgrid

图8 工况1仿真波形

Fig.8 Simulation results of Case 1

图9 工况2仿真波形

Fig.9 Simulation results of Case 2

图10 工况3仿真波形

Fig.10 Simulation results of Case 3

参考文献 20

[1]	李霞林, 郭力, 王成山, 等. 直流微电网关键技术研究综述[J]. 中国电机工程学报, 2016,36(1):2-17.
	LI Xialin, GUO Li, WANG Chengshan, et al. Key technologies of DC microgrids: An overview[J]. Proceedings of the CSEE, 2016,36(1):2-17.
[2]	DRAGIĆEVIĆ T, Lu X, VASQUEZ J C, et al. DC microgrids:Part I: A review of control strategies and stabilization techniques[J]. IEEE Transactions on Power Electronics, 2015,31(7):4876-4891.
[3]	杨新法, 苏剑, 吕志鹏, 等. 微电网技术综述[J]. 中国电机工程学报, 2014,34(1): 57-70.
	YANG Xinfa, SU Jian, LÜ Zhipeng, et al. Overview on micro-grid technology[J]. Proceedings of the CSEE, 2014,34(1): 57-70.
[4]	王成山, 武震, 李鹏. 微电网关键技术研究[J]. 电工技术学报, 2014,29(2): 1-12.
	WANG Chengshan, WU Zhen, LI Peng. Research on key technologies of microgrid[J]. Transactions of China Electrotechnical society, 2014,29(2): 1-12.
[5]	张犁, 孙凯, 吴田进, 等. 基于光伏发电的直流微电网能量变换与管理[J]. 电工技术学报, 2013,28(2):248-254.
	ZHANG Li, SUN Kai, WU Tianjin, et al. Energy conversion and management for DC microgrid based on photovoltaic generation[J]. Transactions of China Electrotechnical Society, 2013,28(2):248-254.
[6]	EGHTEDARPOUR N, FARJAH E. Control strategy for distributed integration of photovoltaic and energy storage systems in DC micro-grids[J]. Renewable Energy, 2012,45:96-110. doi: 10.1016/j.renene.2012.02.017 URL
[7]	郭洪智, 张勤进, 刘彦呈, 等. 基于滑模的直流微电网光伏系统无缝切换策略[J]. 电力系统及其自动化学报, 2019,31(8):13-20.
	GUO Hongzhi, ZHANG Qinjin, LIU Yancheng, et al. Seamless switching control strategy for photovoltaic system in DC microgrid based on sliding-mode control[J]. Proceedings of the CSU-EPSA, 2019,31(8):13-20.
[8]	张野, 郭力, 贾宏杰, 等. 基于电池荷电状态和可变滤波时间常数的储能控制方法[J]. 电力系统自动化, 2012,36(6):34-38, 62.
	ZHANG Ye, GUO Li, JIA Hongjie, et al. An energy storage control method based on state of charge and variable filter time constant[J]. Automation of Electric Power Systems, 2012,36(6):34-38, 62.
[9]	王成山, 李微, 王议锋, 等. 直流微电网母线电压波动分类及抑制方法综述[J]. 中国电机工程学报, 2017,37(1):84-98.
	WANG Chengshan, LI Wei, WANG Yifeng, et al. DC bus voltage fluctuation classification and restraint methods review for DC microgrid[J]. Proceedings of the CSEE, 2017,37(1):84-98.
[10]	周天沛, 孙伟. 微网中的蓄电池循环寿命均衡化管理[J]. 电网技术, 2017,41(7):2237-2246.
	ZHOU Tianpei, SUN Wei. Battery cycle life equalization management in microgrid[J]. Power System Technology, 2017,41(7):2237-2246.
[11]	章竹耀, 肖欣, 郭晓丽, 等. 基于储能电池的光伏功率波动平抑策略[J]. 电力建设, 2016,37(8):90-95.
	ZHANG Zhuyao, XIAO Xin, GUO Xiaoli, et al. Restraining strategy of photovoltaic power fluctuation based on energy storage battery[J]. Electric Power Construction, 2016,37(8):90-95.
[12]	米阳, 纪宏澎, 何星瑭, 等. 多储能独立直流微电网自适应分级协调控制[J]. 中国电机工程学报, 2018,38(7):1980-1989, 2213.
	MI Yang, JI Hongpeng, HE Xingtang, et al. Adaptive hierarchical coordinated control of multi-energy storage in isolated DC microgrid[J]. Proceedings of the CSEE, 2018,38(7):1980-1989, 2213.
[13]	张继元, 舒杰, 宁佳, 等. 考虑SOC自均衡的光储独立微电网协调控制[J]. 电工技术学报, 2018,33(S2):527-537.
	ZHANG Jiyuan, SHU Jie, NING Jia, et al. Coordinated control for PV/storage hybrid islanded microgrid considering SOC balancing[J]. Transactions of China Electrotechnical Society, 2018,33(S2):527-537.
[14]	HAN Y, CHEN W R, LI Q. Energy management strategy based on multiple operating states for a photovoltaic/fuel cell/energy storage DC microgrid[J]. Energies, 2017,10(136):1-15. doi: 10.3390/en10010001 URL
[15]	邱摇摇, 杨秀, 何虹历. 自治直流微电网分层控制策略[J]. 电力建设, 2016,37(10):41-47.
	QIU Yaoyao, YANG Xiu, HE Hongli. A hierarchical control strategy of autonomous DC microgrid[J]. Electric Power Construction, 2016,37(10):41-47.
[16]	王盼宝, 王卫, 孟尼娜, 等. 直流微电网离网与并网运行统一控制策略[J]. 中国电机工程学报, 2015,35(17):4388-4396.
	WANG Panbao, WANG Wei, MENG Nina, et al. Unified control strategy of islanding and grid-connected operations for DC microgrid[J]. Proceedings of the CSEE, 2015,35(17):4388-4396.
[17]	DRAGIČEVICĆ T, GUERRERO J M, VASQUEZ J C, et al. Supervisory control of an adaptive-droop regulated DC microgrid with battery management capability[J]. IEEE Transactions on Power Electronics, 2014,29(2):695-706. doi: 10.1109/TPEL.2013.2257857 URL
[18]	LU X N, SUN K, GUERRERO J M, et al. Double-quadrant state-of-charge-based droop control method for distributed energy storage systems in autonomous DC Microgrids[J]. IEEE Transactions on Smart Grid, 2015,6(1):147-157. doi: 10.1109/TSG.5165411 URL
[19]	米阳, 吴彦伟, 朱银珠, 等. 含负荷功率自动分配的独立直流微电网协调控制[J]. 电网技术, 2017,41(2):440-447.
	MI Yang, WU Yanwei, ZHU Yinzhu, et al. Coordinated control for autonomous DC microgrid with dynamic load power sharing[J]. Power System Technology, 2017,41(2):440-447.
[20]	SANGWONGWANICH A, Yang Y, BLAABJERG F. A cost-effective power ramp-rate control strategy for single-phase two-stage grid-connected photovoltaic systems[C]// 2016 IEEE Energy Conversion Congress and Exposition (ECCE). IEEE, 2016: 1-7.