Three-Phase Grid-Connected Inverter Power Control under Unbalanced Grid Conditions Using a Proportional-Resonant Control Method

Abstract

Proposed in this article is bidirectional real and reactive power control of a three-phase grid-connected inverter under unbalanced grid conditions using a proportional-resonance controller. Different unbalanced grid conditions have been studied, such as unbalanced three-phase load and unbalanced grid impedance. These unbalanced scenarios generate unbalanced grid currents and unbalanced point-of-common-coupling (PCC) voltages, causing large oscillations in both real and reactive power transferred to the grid. The purposes of the suggested technique are to balance the grid currents and point-of-common-coupling voltages as well as control the power injected into the grid. As a result, balanced PCC voltages are guaranteed, the oscillation in real and reactive power is reduced, and power control is achieved. The proposed method’s performance has been verified in MATLAB/SIMULINK simulation software, and different experimental results have been obtained using a real-time interface platform, dSPACE DS1202.

Modeling and simulation of PV system with three phase inverter along PV, IV curves using MATLAB/Simulink

“…It follows a non-linear response, often described by the International Electro technical Commission (IEC) standard as the "I-V curve." As the irradiance increases, the current output of the PV system increases, resulting in higher power output [8]. However, the voltage output tends to remain constant.…”

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“…This inadequacy necessitates the exploration of novel control strategies that can effectively address the unique challenges posed by unbalanced grid conditions. The literature reveals a scope of work focusing on the operation of grid-connected converters during unbalanced conditions, contributing insights on flexible control strategies, dynamic saturation schemes to limit output current, and strategies to reduce stress on DC-link capacitors [15][16][17][18]. These approaches do not provide a comprehensive solution to the problem of DC-link voltage oscillation during unbalanced grid conditions.…”

Predictive Current Control of Sensorless Linear Permanent Magnet Synchronous Motor

“…On the other hand, because of the existence of sliding-mode chattering, the influence of current harmonics will be amplified, resulting in large fluctuations in speed. In order to solve this problem, controllers based on proportional resonance controllers, repetitive controllers, and iterative learning controllers have been proposed [23][24][25]. However, the parameters of the controllers often need to be adjusted with the harmonic frequency.…”