Title: An improved grid voltage observation method for grid-connected inverter

Authors: Shuping Song; Xiaobo Sun; Zhihao Zhang; Huping Bao

Addresses: School of Electrical and Automation Engineering, Changshu Institute of Technology, Changshu, Jiangsu, China ' Yangtze Power Co., Ltd., Yichang, Hubei, China ' Jiangsu Equation Electric Power Technology Co., Ltd., Wuxi, Jiangsu, China ' Jiangsu Equation Electric Power Technology Co., Ltd., Wuxi, Jiangsu, China

Abstract: The voltage observation method via sliding mode observer (SMO) is widely used in the predictive control of grid-connected inverter (GCI) without AC voltage sensor. However, conventional methods not only need complex phase and amplitude compensation, but also are greatly affected by low-order harmonics of grid voltage. Therefore, a simple method of voltage phase and amplitude compensation is proposed, which is based on the conventional SMO. Besides, an improved phase-locked loop (PLL) is also adopted to reduce the interference of low-order harmonics in power grid. The improved PLL eliminates the interference of 5th and 7th harmonics and realises the accurate observation of power grid frequency and angle. The effectiveness of the proposed method is verified by MATLAB/Simulink simulation.

Keywords: grid voltage observation; predictive control; grid-connected inverter; GCI; sliding mode observer; SMO; phase-locked loop; PLL.

DOI: 10.1504/IJMIC.2024.135555

International Journal of Modelling, Identification and Control, 2024 Vol.44 No.1, pp.88 - 96

Received: 03 Sep 2022
Received in revised form: 12 Dec 2022
Accepted: 18 Dec 2022
Published online: 18 Dec 2023 *

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