Application of Zero Phase Moving Average Filter in LCL Inverter

doi:10.11985/2023.01.007

Abstract

Abstract:

In the process of grid-connected control, phase-locked technology is the key to the synchronization of grid-connected inverter and power grid. A zero-phase moving average filter second-order generalized integrator phase locked loop(ZPMAF-SOGI-PLL) based on second-order generalized integrator(SOGI) and moving average filter algorithm(MAF) is proposed. By improving the SOGI structure and MAF algorithm, it can be solved that the phase-locked loop can quickly, stably and accurately obtain the positive and negative sequence component voltage, frequency, phase and other parameters from the power grid under unsatisfactory conditions. The stability of this method is analyzed by modern control theory, and the SOGI-PLL method is used for phase locking in the link of grid-connected inverter control. The simulation and experimental results under unbalanced grid voltage and high-order harmonic conditions show that the proposed method enables the LCL grid-connected inverter to accurately detect the positive and negative sequence components, so that the harmonic content of the grid-connected current is reduced to 1.89% and 2.71% under the two conditions, respectively, and the operation of the LCL grid-connected inverter is more stable.

Key words: LCL grid-connected inverter, second-order generalized integrator, phase-locked loop, zero-phase sliding average filter

CLC Number:

TM464

ZHOU Li, LIU Yiming, LIU Jinshu, LI Jingming. Application of Zero Phase Moving Average Filter in LCL Inverter[J]. Journal of Electrical Engineering, 2023, 18(1): 68-84.

Figures/Tables 16

References 19

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序号	参数	数值
1	直流源电压U_dc/V	500
2	电网电压U_g/V	311
3	滤波电容C/μF	8
4	逆变侧滤波电感L₁/mH	3
5	网侧电感L₂/mH	2
6	开关频率f_s/kHz	10
7	额定频率f_n/Hz	50
8	额定有功功率P_n/kW	20
9	谐振频率ω₀/(rad/s)	314
10	截止频率ω_c/(rad/s)	5
11	比例调节系数K_p	12.732
12	积分调节系数K_i	6.366
13	改进型SOGI的LPF阻尼系数τ	0.707
14	QPR控制器比例系数K_P	15
15	QPR控制器谐振系数K_R	100