Investigation of stability optimization of grid-forming energy storage converters based on virtual bus voltage control

doi:10.19799/j.cnki.2095-4239.2023.0818

Abstract

Abstract:

Since key equipment of new energy technology is connected to the power grid, grid-forming energy storage converters have stability problems in strong power grids. Aiming to resolve this problem, this study proposes a method for stability optimization of grid-forming energy storage converters based on virtual bus voltage control. First, the state space small signal model of a grid-forming energy storage converter is established, and the characteristic root analysis method is used to obtain the stability conditions of the grid-forming energy storage converter that becomes worse or even oscillates under strong power grid conditions. Subsequently, a stability optimization method based on virtual bus voltage control is proposed. By changing the position of the active power loop tracking the grid voltage phase, the grid impedance is equivalently improved, thus improving the stability of the grid-forming energy storage converter system under strong power grid conditions. Subsequently, the eigenvalue change trend and stability improvement effect of the converter system before and after adding the virtual bus voltage control under different working conditions are analyzed. Simultaneously, the influence of the compensation coefficient k and the time constant t in the virtual bus voltage control parameters on the stability of the converter system is analyzed and the general parameter design range is provided. Finally, a grid-forming model of the grid-forming energy storage converter is built in MATLAB/Simulink for time-domain verification, and a hardware-in-the-loop experimental platform is further built for semi-physical verification. The study results show that the stability of the grid-forming energy storage converter based on virtual bus voltage control is significantly improved under strong power grid conditions.

Key words: grid-following energy storage, small-signal stability, virtual bus voltage control, stability optimization

CLC Number:

TM 712

Wenbo YAN, Yunhui HUANG, Dong WANG, Jinrui TANG, Keliang ZHOU. Investigation of stability optimization of grid-forming energy storage converters based on virtual bus voltage control[J]. Energy Storage Science and Technology, 2024, 13(5): 1532-1541.

Figures/Tables 14

Fig. 1

Fig. 2

Table 1

Fig. 3

Fig. 4

Fig. 5

Fig. 6

Fig. 7

Table 2

Fig. 8

Fig. 9

Fig. 10

Fig. 11

Fig. 12

References 20

1	付熙坤, 黄萌, 凌扬坚, 等.功率耦合和电流限幅影响下构网型变流器的暂态同步稳定分析[J]. 中国电机工程学报, 2024, 44(7): 2815-2824.
	FU X K, HUANG M, LING Y J, et al. Transient synchronization stability analysis of grid-forming converter influenced by power-coupling and current-limiting[J]. Proceedings of the CSEE, 2024, 44(7): 2815-2824.
2	耿华, 何长军, 刘浴霜, 等. 新能源电力系统的暂态同步稳定研究综述[J]. 高电压技术, 2022, 48(9): 3367-3383.
	GENG H, HE C J, LIU Y S, et al. Overview on transient synchronization stability of renewable-rich power systems[J]. High Voltage Engineering, 2022, 48(9): 3367-3383.
3	许诘翊, 刘威, 刘树, 等. 电力系统变流器构网控制技术的现状与发展趋势[J]. 电网技术, 2022, 46(9): 3586-3595.
	XU J Y, LIU W, LIU S, et al. Current state and development trends of power system converter grid-forming control technology[J]. Power System Technology, 2022, 46(9): 3586-3595.
4	邱晓燕, 林号缙, 周毅, 等. 基于混合同步控制的构网型逆变器并网系统小扰动稳定性分析[J]. 电力自动化设备, 2023, 43(9): 172-178, 185.
	QIU X Y, LIN H J, ZHOU Y, et al. Study on small-signal stability of grid-connected grid-forming inverter system based on hybrid-synchronous control[J]. Electric Power Automation Equipment, 2023, 43(9): 172-178, 185.
5	YANG C R, HUANG L B, XIN H H, et al. Placing grid-forming converters to enhance small signal stability of PLL-integrated power systems[J]. IEEE Transactions on Power Systems, 2021, 36(4): 3563-3573.
6	HONG Z K, XU H S, HOU Z Q, et al. Origin of anomalous instability of grid-forming converters tied to stiff grid[J]. IET Renewable Power Generation, 2023, 17(10): 2563-2574.
7	MATEVOSYAN J, BADRZADEH B, PREVOST T, et al. Grid-forming inverters: Are they the key for high renewable penetration?[J]. IEEE Power and Energy Magazine, 2019, 17(6): 89-98.
8	詹长江, 吴恒, 王雄飞, 等. 构网型变流器稳定性研究综述[J]. 中国电机工程学报, 2023, 43(6): 2339-2359.
	ZHAN C J, WU H, WANG X F, et al. An overview of stability studies of grid-forming voltage source converters[J]. Proceedings of the CSEE, 2023, 43(6): 2339-2359.
9	HARNEFORS L, MAHAFUGUR RAHMAN F M, HINKKANEN M, et al. Reference-feedforward power-synchronization control[J]. IEEE Transactions on Power Electronics, 2020, 35(9): 8878-8881.
10	洪镇堃, 占萌. 构网型变流器并网系统在强弱电网下的分岔分析[J]. 电力自动化设备, 2023, 43(9): 27-32, 54.
	HONG Z K, ZHAN M. Bifurcation analysis of grid-forming converter system connected with stiff or weak AC grids[J]. Electric Power Automation Equipment, 2023, 43(9): 27-32, 54.
11	周京华, 李津. 微电网三电平储能变流器优化控制技术综述[J]. 高电压技术, 2023, 49(8): 3137-3148.
	ZHOU J H, LI J. Review of optimal control technology for three-level power converter system in microgrid[J]. High Voltage Engineering, 2023, 49(8): 3137-3148.
12	史明明, 姜云龙, 史鸿飞, 等. 集成有源阻尼器功能的并网逆变器虚拟电阻补偿控制方法[J/OL]. 电力自动化设备: 1-14[2023-11-12]. https://doi.org/10.16081/j.epae.202307024.
	SHI M M,JIANG Y L,SHI H F, et al. Virtual resistance compensation control method for grid-connected inverter integrated with active damper function[J/OL]. Electric Power Automation Equipment: 1-14[2023-11-12]. https://doi.org/10.16081/j.epae.202307024.
13	卢栩舜, 朱金荣, 王磊. 基于虚拟同步发电机的并离网控制策略优化[J]. 电子设计工程, 2023, 31(13): 156-162.
	LU X S, ZHU J R, WANG L. Optimization of grid-connected/islanded control strategy based on virtual synchronous generator[J]. Electronic Design Engineering, 2023, 31(13): 156-162.
14	郭春义, 吕乃航, 张加卿. 提高LCC-HVDC在弱交流系统下的稳定性和动态性能的控制参数优化方法[J]. 电工技术学报, 2023, 38(7): 1751-1764, 1779.
	GUO C Y, LÜ N H, ZHANG J Q. Optimization of control parameters to enhance stability and dynamic performance of LCC-HVDC under weak AC condition[J]. Transactions of China Electrotechnical Society, 2023, 38(7): 1751-1764, 1779.
15	黄通, 陈新, 张东辉, 等. 考虑电压前馈控制的MMC-HVDC并网稳定性分析及其阻抗控制优化方法[J]. 中国电机工程学报, 2023, 43(23): 8987-8999.
	HUANG T, CHEN X, ZHANG D H, et al. MMC-HVDC integrated system stability analysis and impedance optimization method with consideration of voltage feed-forward control[J]. Proceedings of the CSEE, 2023, 43(23): 8987-8999.
16	刘永慧, 王跃, 彭阳, 等. 提升组网型变流器并网交互稳定性的控制参数整定方法[J]. 电网技术, 2023, 47(1): 16-27.
	LIU Y H, WANG Y, PENG Y, et al. Parameter tuning for improving interaction stability of grid-forming converter and power grid[J]. Power System Technology, 2023, 47(1): 16-27.
17	吴家杰, 陈新, 张东辉, 等. 构网型储能变换器在新能源接入场景下并网稳定性分析及提升策略[J/OL]. 中国电机工程学报: 1-14[2023-11-12]. https://doi.org/10.13334/j.0258-8013.pcsee.231337.
	WU J J, CHEN X, ZHANG D H, et al. Grid-connected stability analysis and improvement strategy for grid-forming energy storage system in new energy access scene[J/OL]. Proceedings of the CSEE: 1-14[2023-11-12]. https://doi.org/10.13334/j.0258-8013.pcsee.231337.
18	王吉利, 占领, 张钢, 等. 提高构网型储能系统功角稳定性的附加阻尼方法[J]. 电力科学与技术学报, 2023, 38(4): 75-81, 103.
	WANG J L, ZHAN L, ZHANG G, et al. Additional damping method for improving the power angle stability of grid-forming energy storage system[J]. Journal of Electric Power Science and Technology, 2023, 38(4): 75-81, 103.
19	ZHOU Z Q, PUGLIESE S, LISERRE M. Stability comparison of grid-forming converters with different power calculation strategies[C]//2023 IEEE 14th International Symposium on Power Electronics for Distributed Generation Systems (PEDG). June 9-12, 2023. Shanghai, China. IEEE, 2023: 800-805.
20	刘欣, 郭志博, 贾焦心, 等. 基于序阻抗的虚拟同步发电机并网稳定性分析及虚拟阻抗设计[J]. 电工技术学报, 2023, 38(15): 4130-4146.
	LIU X, GUO Z B, JIA J X, et al. Stability analysis and virtual impedance design of virtual synchronous machine based on sequence impedance[J]. Transactions of China Electrotechnical Society, 2023, 38(15): 4130-4146.

电网强度和输出功率	SCR=5, P=1.0 p.u.	SCR=6, P=1.0 p.u.	SCR=5, P=0.8 p.u.	SCR=5, P=1.2 p.u.
主导特征根	(-0.35±25.04i)	(0.10±25.89i)	(-0.98±23.99i)	(0.14±25.81i)
振荡频率	3.98	4.12	3.82	4.11
阻尼比	0.014	-0.004	0.041	-0.005

参数		含义	数值
系统参数	S_b	变流器基准容量	0.1 MW
	U_N	变流器基准电压	381 V
	P_ref	变流器给定有功功率	0.1 MW
	Q_ref	变流器给定无功功率	0 Var
	U_dc	储能直流侧电压	700 V
	U_t	并网电压	381 V
	U_g	电网电压	381 V
	L_c	滤波电感	3 mH
	L_g	线路电感	1.1 mH

控制参数	D_p	阻尼系数	1.5
	J	惯量系数	20
	K_q	无功控制系数	5
	k_p1，k_i1	电压环比例，积分增益	5，200
	k_p2，k_i2	电流环比例，积分增益	0.3，0.05

[1]	Xiaying XIAO, Chuanguang FAN, Feng GUO, Tianxin YANG, Dong WANG, Yunhui HUANG. Optimal allocation of energy storage power station based on improved multi-objective particle swarm optimization [J]. Energy Storage Science and Technology, 2024, 13(2): 503-514.
[2]	Xin WU, Wenju SHANG, Zhiyong MA, Wei TENG, Shuang ZHANG, Hairong LUO. Coordinated control method for pumped and flywheel hybrid energy storage system [J]. Energy Storage Science and Technology, 2023, 12(2): 468-476.
[3]	Jie SONG, Linxiao GENG, Yongfu SANG, Rongbin WEN, Peng SUN, Linjuan GONG. Study on primary frequency modulation capacity planning of thermal power unit assisted by hybrid energy storage based on EMD decomposition [J]. Energy Storage Science and Technology, 2023, 12(2): 496-503.
[4]	Hao QIN, Lijun QIN, Xuechen BAI, Cong LI. A control strategy of flywheel energy storage system participating frequency regulation with pumped storage [J]. Energy Storage Science and Technology, 2022, 11(12): 3915-3925.
[5]	Linxuan HE, Wenyan LI. Simulation of the primary frequency modulation process of thermal power units with the auxiliary of flywheel energy storage [J]. Energy Storage Science and Technology, 2021, 10(5): 1679-1686.