The Solution for Grid-Connected Inverters in Order to Comply with Grid-Code: Integrating SHEPWM and 30° Phase-Shifted Two-Channel Inverter Topology

This paper presents an approach to optimizing control algorithms for a grid-connected inverter. The scientific novelty of the solution is expressed in a hybrid approach to inverter control, combining a two-channel inverter circuit <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(6 \mathrm{n} \pm 1$</tex> harmonic mitigation) with the optimal synchronous modulation method, Selective Harmonic Elimination Pulse Width Modulation, which eliminates <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$12 n \pm 1$</tex> harmonics. This combination ensures more stable and reliable power unit operation under various grid conditions. A detailed harmonic spectrum analysis at the Point of Common Coupling was conducted. Each modulation pattern was evaluated under different operating conditions, including connection to high-, medium-, and low-power grids, operation on a matched load, and operation for auxiliary power consumption. The proposed optimization aims to enhance operational efficiency, minimize power fluctuations, and improve the system's response to grid disturbances. The study includes a comprehensive theoretical analysis, the development of mathematical models, and the implementation of optimized synchronous modulation patterns in MATLAB/Simulink. Experimental validation demonstrates a significant reduction in total harmonic distortion and an overall improvement in power quality compliance. The experimental results confirm a significant reduction in Total Harmonic Distortion and an overall improvement in power quality compliance. These findings suggest practical applications in modern power systems, where power quality and efficiency are crucial.