LCL Grid-Connected Inverters Control Strategy Based on Improved Fuzzy Linear Active Disturbance Rejection Control

doi:10.12096/j.2096-4528.pgt.24132

Abstract

Abstract:

Objectives In complex grid environments, traditional control methods for LCL grid-connected inverter systems suffer from poor grid current quality, inadequate dynamic performance, and inherent resonance peaks. To address these issues, a Fuzzy linear active disturbance rejection control (Fuzzy-LADRC) strategy is proposed. Methods The disturbance rejection capability is enhanced by modifying the error equation of the traditional linear extended state observer. The modified error equation is then combined with fuzzy logic control to achieve adaptive control of the controller parameters. The improved Fuzzy-LADRC strategy is applied to both the phase-locked loop and the current loop of the LCL control system. The system’s stability and disturbance rejection performance are verified by using Lyapunov stability analysis and frequency-domain analysis. Finally, MATLAB/Simulink simulations are conducted to validate the effectiveness of the proposed control strategy. Results The improved Fuzzy-LADRC strategy shows superior performance in terms of grid current harmonic distortion, offset, and dynamic response time under three different operating conditions compared with other control methods. Additionally, this control strategy simplifies the control structure by eliminating the need for additional damping components. Conclusions The improved Fuzzy-LADRC strategy effectively improves the system’s disturbance rejection capability and grid current quality while reducing system costs and achieving good dynamic performance. It provides a new approach for the control of LCL grid-connected inverters.

Key words: power grid, active disturbance rejection control, grid-connected inverter, fuzzy control, control strategy, stability, harmonics, distortion rate

CLC Number:

TK 011

Hang LI, Kunli GUO, Peng YANG, Jiajun LÜ, Beilei REN, Chenming QU, Tinghua ZHU, Yifan HAO. LCL Grid-Connected Inverters Control Strategy Based on Improved Fuzzy Linear Active Disturbance Rejection Control[J]. Power Generation Technology, 2025, 46(2): 409-420.

Figures/Tables 20

Fig. 1 Block diagram of three-phase LCL grid-connected inverter system

Fig. 2 Control block diagram of three-phase LCL grid-connected inverter system

Fig. 3 Bode plots of LCL transfer function and reduced-order transfer function

Fig. 4 Block diagram of improved first-order LADRC

Fig. 5 Improve LADRC and simplified system block diagram

Fig. 6 Improved LADRC equivalent control block diagram based on LCL system

Fig. 7 PLL equivalent control block diagram based on improved LADRC

Fig. 8 Control block diagram based on LCL System

Fig. 9 Output bode plot of LCL system with changes in ωc and ω0

Fig. 10 Disturbance bode plot of LCL system with changes in ωc和ω0

Fig. 11 Disturbance bode plot of PLL system with changes in ωc and ω0

Fig. 12 Comparison of improved LADRC and traditional LADRC in LCL system

Fig. 13 Comparison of disturbance between improved LADRC and traditional LADRC in PLL

Fig. 14 Block diagram of improved Fuzzy-LADRC

Tab. 1 Fuzzy control rules

$e$	$e ˙$
$e$	NL	NM	NS	ZO	PS	PM	PL
NL	PL	PL	PM	PM	PS	ZO	ZO
NM	PL	PL	PM	PM	PS	ZO	ZO
NS	PM	PM	PS	PS	ZO	ZO	NS
ZO	PM	PS	PS	ZO	NS	NS	NM
PS	PS	ZO	ZO	NS	NM	NM	NM
PM	ZO	ZO	NS	NM	NM	NL	NL
PL	ZO	NS	NM	NM	NL	NL	NL

Tab. 1 Fuzzy control rules

$e$	$e ˙$
$e$	NL	NM	NS	ZO	PS	PM	PL
NL	PL	PL	PM	PM	PS	ZO	ZO
NM	PL	PL	PM	PM	PS	ZO	ZO
NS	PM	PM	PS	PS	ZO	ZO	NS
ZO	PM	PS	PS	ZO	NS	NS	NM
PS	PS	ZO	ZO	NS	NM	NM	NM
PM	ZO	ZO	NS	NM	NM	NL	NL
PL	ZO	NS	NM	NM	NL	NL	NL

Tab. 2 LCL system parameters

参数	数值	参数	数值
U_dc/V	800	ω₀₁	3 000
电网电压/V	220	PI参数 $k p$	0.026
L₁/mH	2	PI参数 $k i$	167
L₂/mH	0.5	有源阻尼系数	0.4
C/ $μ F$	4.7	ω_c2	50
开关频率f_sw/kHz	10	ω₀₂	100
ω_c1	2 000	$b 0$	1

Tab. 2 LCL system parameters

参数	数值	参数	数值
U_dc/V	800	ω₀₁	3 000
电网电压/V	220	PI参数 $k p$	0.026
L₁/mH	2	PI参数 $k i$	167
L₂/mH	0.5	有源阻尼系数	0.4
C/ $μ F$	4.7	ω_c2	50
开关频率f_sw/kHz	10	ω₀₂	100
ω_c1	2 000	$b 0$	1

Fig. 15 Grid-connected current of different control strategies under sudden current surge

Tab. 3 Grid-connected current offset of different control strategies

控制策略	a相	b相	c相	总和
有源阻尼+PI	2.62	21.30	7.40	31.32
一阶LADRC	4.40	5.66	6.10	16.16
改进LADRC	2.34	2.76	3.15	8.25
改进Fuzzy-LADRC	1.06	1.46	0.88	3.40

Fig. 16 Grid-connected current and voltage of different control strategies during grid voltage sag

Fig. 17 Grid-connected current and voltage of different control strategies under harmonic injection

References 23

1	常继凯，舒勤，李鸿鑫，等．计及电缆分布电容的并网逆变器谐振特性与抑制[J]．电力科学与技术学报，2023，38(3)：114-123． doi:10.19781/j.issn.1673-9140.2023.03.012
	CHANG J K， SHU Q， LI H X，et al ．Resonance characteristics and suppression of grid-connected inverter system considering cable distributed capacitance[J]．Journal of Electric Power Science and Technology，2023，38(3)：114-123． doi:10.19781/j.issn.1673-9140.2023.03.012
2	方健，李辉．基于状态重构准谐振扩张状态观测器的LCL型并网逆变器电流控制策略研究[J]．发电技术，2024，45(1)：170-179． doi:10.12096/j.2096-4528.pgt.22141
	FANG J， LI H ．Research on current control strategy of the LCL-type grid-connected inverter based on state reconfiguration with quasi resonant-extended state observer[J]．Power Generation Technology，2024，45(1)：170-179． doi:10.12096/j.2096-4528.pgt.22141
3	陈伟，张岩，屠一鸣，等．LCL型并网逆变器临界无源阻尼参数设计[J]．电力建设，2022，43(1)：70-77．
	CHEN W， ZHANG Y， TU Y M，et al ．Design of critical passive damping parameters for LCL-type grid-connected inverter[J]．Electric Power Construction，2022，43(1)：70-77．
4	赵铁英，高宁，杨杰，等．基于PI控制器有源阻尼的并网逆变器自适应改进策略[J]．太阳能学报，2023，44(5)：152-161．
	ZHAO T Y， GAO N， YANG J，et al ．Adaptive improvement strategy for grid-connected inverter based on active damping of pi controllers[J]．Acta Energiae Solaris Sinica，2023，44(5)：152-161．
5	杨树德，李旺，徐佳，等．基于并网电流谐波微分的有源阻尼策略[J]．电工技术学报，2023，38(23)：6305-6317．
	YANG S D， LI W， XU J，et al ．Research on active damping strategy based on the differentiation of injected grid current harmonics[J]．Transactions of China Electrotechnical Society，2023，38(23)：6305-6317．
6	陈关旭，何国锋，董燕飞，等．基于WACC的三相光伏并网逆变器LADRC控制器设计[J]．可再生能源，2024，42(6)：789-795．
	CHEN G X， HE G F， DONG Y F，et al ．LADRC controller design of three-phase photovoltaic grid-connected inverter based on WACC[J]．Renewable Energy Resources，2024，42(6)：789-795．
7	刘春喜，田宝奇，刘志乐，等．NPC型三电平并网逆变器自适应模型预测控制[J]．电力系统及其自动化学报，2023，35(1)：143-151．
	LIU C X， TIAN B Q， LIU Z L，et al ．Adaptive model predictive control for NPC-type three-level grid-connected inverter[J]．Proceedings of the CSU-EPSA，2023，35(1)：143-151．
8	任蓓蕾，郭昆丽，蔡维正，等．基于改进线性自抗扰控制器的直驱风机次同步振荡抑制及阻抗稳定性分析[J]．发电技术，2024，45(6)：1135-1145． doi:10.12096/j.2096-4528.pgt.23076
	REN B L， GUO K L， CAI W Z，et al ．Subsynchronous oscillation suppression of direct-drive wind turbines based on improved linear active disturbance rejection control and analysis of impedance stability[J]．Power Generation Technology，2024，45(6)：1135-1145． doi:10.12096/j.2096-4528.pgt.23076
9	周雪松，尹博文．基于自抗扰控制的并网逆变器环流抑制策略[J]．电测与仪表，2024，61(9)：92-100． doi:10.19753/j.issn1001-1390.2024.09.012
	ZHOU X S， YIN B W ．Circulating current suppression strategy of grid-connected inverter based on active disturbance rejection control[J]．Electrical Measurement & Instrumentation，2024，61(9)：92-100． doi:10.19753/j.issn1001-1390.2024.09.012
10	范永胜，陈卓，郝勇生，等．基于相位补偿的过热汽温自抗扰控制[J]．电力工程技术，2024，43(3)：254-261．
	FAN Y S， CHEN Z， HAO Y S，et al ．Phase compensation based active disturbance rejection control for superheated steam temperature[J]．Electric Power Engineering Technology，2024，43(3)：254-261．
11	李世龙，李龙江，刘欣博，等．一种增强稳定性的储能变流器线性自抗扰控制参数整定方法[J]．中国电力，2024，57(10)：25-35．
	LI S L， LI L J， LIU X B，et al ．Linear active disturbance rejection control parameter tuning method for energy storage converter with enhanced stability[J]．Electric Power，2024，57(10)：25-35．
12	周雪松，郭帅朝，马幼捷，等．基于改进自抗扰的变流系统直流母线电压波动抑制策略[J]．电力系统保护与控制，2023，51(3)：68-78．
	ZHOU X S， GUO S C， MA Y J，et al ．DC bus voltage fluctuation suppression strategy of a converter system based on improved active disturbance rejection[J]．Power System Protection and Control，2023，51(3)：68-78．
13	CAI Y， HE Y， ZHOU H，et al ．Active-damping disturbance-rejection control strategy of LCL grid-connected inverter based on inverter-side-current feedback[J]．IEEE Journal of Emerging and Selected Topics in Power Electronics，2021，9(6)：7183-7198． doi:10.1109/jestpe.2020.3017678
14	石磊，周宏涛，赵元莘，等．光伏多功能并网逆变器迭代SMC+LADRC电流内环控制策略研究[J]．智慧电力，2023，51(4)：107-114．
	SHI L， ZHOU H T， ZHAO Y S，et al ．Iterative SMC+LADRC current inner loop control strategy of photovoltaic multi-function grid connected inverter[J]．Smart Power，2023，51(4)：107-114．
15	周雪松，郭帅朝，马幼婕，等．基于LADRC和准PR的三相LCL型光伏并网逆变器谐波谐振抑制策略[J]．太阳能学报，2023，44(3)：465-474．
	ZHOU X S， GUO S C， MA Y J，et al ．Harmonic resonance suppression strategy of three-phase LCL photovoltaic grid-connected inverter based on LADRC and quasi PR[J]．Acta Energiae Solaris Sinica，2023，44(3)：465-474．
16	ZHANG H， XIAN J， SHI J，et al ．High performance decoupling current control by linear extended state observer for three-phase grid-connected inverter with an LCL filter[J]．IEEE Access，2020，8：13119-13127． doi:10.1109/access.2020.2965650
17	杨林，曾江，黄仲龙．线性自抗扰技术在LCL逆变器并网电流控制及有源阻尼中的应用[J]．电网技术，2019，43(4)：1378-1386．
	YANG L， ZENG J， HUANG Z L ．Application of linear active disturbance rejection technique in grid-connected current control and active damping of LCL type inverter[J]．Power System Technology，2019，43(4)：1378-1386．
18	马幼捷，张彤，周雪松．基于模糊自适应的固态变压器逆变级改进LADRC控制[J]．电力系统及其自动化学报，2022，34(3)：123-131．
	MA Y J， ZHANG T， ZHOU X S ．Improved LADRC control for inverter stage of solid-state transformer based on fuzzy adaptive method[J]．Proceedings of the CSU-EPSA，2022，34(3)：123-131．
19	张建功，周雪松，马幼捷，等．基于Buck变换器的模糊自抗扰Hopf分岔扰动抑制策略[J]．电力系统保护与控制，2023，51(15)：12-21．
	ZHANG J G， ZHOU X S， MA Y J，et al ．Fuzzy ADRC Hopf bifurcation disturbance suppression strategy based on a Buck converter[J]．Power System Protection and Control，2023，51(15)：12-21．
20	刘勇，杨浩，马士翔，等．基于并网逆变器的级联性自抗扰控制策略[J]．控制工程，2023，30(5)：788-795．
	LIU Y， YANG H， MA S X，et al ．Cascaded linear active disturbance rejection control strategy based on grid-connected[J]．Control Engineering of China，2023，30(5)：788-795．
21	马明，廖鹏，蔡雨希，等．LCL并网逆变器的自抗扰控制策略[J]．高电压技术，2021，47(6)：2223-2231．
	MA M， LIAO P， CAI Y X，et al ．Active disturbance rejection control strategy of LCL grid-connected inverter[J]．High Voltage Engineering，2021，47(6)：2223-2231．
22	杨天翔，程志江，杨涵棣，等．基于自抗扰控制的风电并网变流器锁相环设计[J]．太阳能学报，2023，44(4)：147-155．
	YANG T X， CHENG Z J， YANG H D，et al ．Design of phase-locked loop of grid connected converter based on active disturbance rejection control[J]．Acta Energiae Solaris Sinica，2023，44(4)：147-155．
23	LIU Q， ZHANG L， QIAN Q ．Fast LADRC-type phase-locked loop with adaptive extended state observer[J]．IEEE Transactions on Industrial Electronics，2024，71(8)：8268-8278． doi:10.1109/tie.2023.3317863

[1]	Zhenglong SUN, Jiqiang SAN. Research on Doubly-Fed Wind Turbine Shaft System With Virtual Inertia for Torsional Vibration Analysis [J]. Power Generation Technology, 2025, 46(2): 314-325.
[2]	Yang ZHENG, Yucheng REN, Yuwei WANG, Dingji XU, Huimin YANG. Evaluation of Comprehensive Benefits of Electric Energy Substitution in Regional Power Grids Based on Improved Cloud Model [J]. Power Generation Technology, 2025, 46(2): 399-408.
[3]	Beilei REN, Kunli GUO, Weizheng CAI, Bohao LI, Tinghua ZHU, Lingtao LI. Subsynchronous Oscillation Suppression of Direct-Drive Wind Turbines Based on Improved Linear Active Disturbance Rejection Control and Analysis of Impedance Stability [J]. Power Generation Technology, 2024, 45(6): 1135-1145.
[4]	Chaojun GUAN, Zhengling LEI, Haibo HUO, Fang WANG, Guoquan YAO, Tao LIU. Active Disturbance Rejection Control of Output Voltage of Solid Oxide Fuel Cell Based on Reinforcement Learning [J]. Power Generation Technology, 2024, 45(6): 1163-1172.
[5]	Wanlin DU, Ling WANG, Wei LUO, Yuanzhe ZHU, Hong LÜ, Xiaonan MA, Xia ZHOU. Voltage Hierarchical Control Strategy of Active Distribution Network Based on Deep Reinforcement Learning [J]. Power Generation Technology, 2024, 45(4): 734-743.
[6]	Dan ZHOU, Zhi YUAN, Ji LI, Wei FAN. An Advanced Fuzzy Control Strategy for Hybrid Energy Storage Systems Considering Smoothing of Wind Power Fluctuations at Future Moments [J]. Power Generation Technology, 2024, 45(3): 412-422.
[7]	Fangfang WANG, Pengwei YANG, Guangjin ZHAO, Qi LI, Xiaona LIU, Shuangchen MA. Development and Challenge of Flexible Operation Technology of Thermal Power Units Under New Power System [J]. Power Generation Technology, 2024, 45(2): 189-198.
[8]	Zhijun JIA, Wei FAN, Shaojun REN, Tangbin WEI. Research on Combustion Stability of a 600 MW Subcritical Power Unit Under Long-Term Deep Peak Shaving [J]. Power Generation Technology, 2024, 45(2): 216-225.
[9]	Zheng YANG, Yipeng SUN, Zhiqiang WEN, Liang CHENG, Zhanguo LI. Research on Dry-Wet Conversion Strategy of Supercritical Thermal Power Units Under Deep Peaking Condition [J]. Power Generation Technology, 2024, 45(2): 233-239.
[10]	Yeqing ZHANG, Wenbin CHEN, Lüjun XU, Xingwen JIANG. Multi-Virtual Power Plant-Oriented Dynamic Aggregation Control Strategy Based on Hierarchical Partition and Multi-Layer Complementation [J]. Power Generation Technology, 2024, 45(1): 162-169.
[11]	Jian FANG, Hui LI. Research on Current Control Strategy of the LCL-Type Grid-Connected Inverter Based on State Reconfiguration With Quasi Resonant-Extended State Observer [J]. Power Generation Technology, 2024, 45(1): 170-179.
[12]	Xiaojie PAN, Youping XU, Zhijun XIE, Yukun WANG, Mujie ZHANG, Mengxuan SHI, Kun MA, Wei HU. Power System Transient Stability Preventive Control Optimization Method Driven by Stacking Ensemble Learning [J]. Power Generation Technology, 2023, 44(6): 865-874.
[13]	Xin TANG, Yiran QIAN, Huawei FANG, Yang LI, Siguang LI, Jingwei YI, Weixiong CHEN, Junjie YAN. A Review of Control Strategies for Supercritical Carbon Dioxide Brayton Cycle [J]. Power Generation Technology, 2023, 44(4): 492-501.
[14]	Hongbo LIU, Yutong YAN, Xi WANG, Peng SHI, Li SUN. A Review of Small Signal Stability Studies of Multi-infeed AC-DC Hybrid System [J]. Power Generation Technology, 2023, 44(4): 565-575.
[15]	Chunhui LUO, Tonghua ZOU, QU Gangju, Tao TANG. A Planning Method for Anti-disaster Backbone Grid Considering Economy and Reliability [J]. Power Generation Technology, 2023, 44(3): 425-430.