Open Access

ARTICLE

An Adaptive Harmonic Compensation Strategy for Multiple PV Inverters to Enhance Power Quality in Distribution Networks

Lizhong Lu¹, Guangze Li², Zheng Yang^2,*, Yunjing Liu^1,2, Xiaozhuo Guan¹, Tiebin Guo¹
1 Science and Technology Department, State Grid Jilin Electric Power Co., Ltd., Jilin, 132000, China
2 School of Electrical Engineering, Northeast Electric Power University, Jilin, 132012, China
* Corresponding Author: Zheng Yang. Email:

Energy Engineering https://doi.org/10.32604/ee.2025.075585

Received 04 November 2025; Accepted 17 December 2025; Published online 09 January 2026

Abstract

With the substantial advancement of the manufacturing industry, a large number of new types of loads are being connected to the distribution network via power electronic devices, exacerbating the deterioration of power quality at the Point of Common Coupling and making harmonic problems increasingly severe. Currently, most researchers focus on improving harmonic suppression performance from the perspective of the controller, but they overlook the fact that excessive performance enhancement may lead to issues such as resonance in the distribution network. To address this, this paper proposes an adaptive harmonic compensation strategy for scenarios with limited capacity and multiple inverters, where the residual capacity and Nyquist stability region constraints jointly determine the compensation coefficients. Firstly, focusing on the coupling relationship between ‘compensation coefficient—equivalent impedance—inner-loop bandwidth’, a small-signal model of the inverter and grid impedance is established. The Nyquist criterion is employed to characterize the closed-loop stability region, providing a parameterized stability boundary for selecting compensation coefficients. Secondly, a Cascaded Generalized Integrator is used to online extract individual harmonic currents, and a compensation mechanism of “detection-reverse injection” is realized by reconstructing the current inner loop. Then, for multiple parallel inverter scenarios, a residual capacity matching algorithm for grid-connected inverters is proposed, which dynamically adjusts compensation coefficients according to the remaining capacity of each PV inverter in the distribution network. Finally, through an analysis of a single-unit grid-connected system, a 33-node distribution network, and a practical case study from a specific region in Jilin Province, the results demonstrate that the proposed control strategy not only significantly reduces the current distortion rate at the point of common coupling but also effectively prevents overload in grid-connected inverters.

---

Keywords

Power quality; harmonic current; multifunctional converter; adaptive harmonic control; residual capacity

---