Stability Enhancement and Harmonic Suppression of a Five-Level Cascaded H-Bridge Inverter for Microgrid Systems using Optimized PI Control

Integrating renewable energy into microgrids requires advanced power conversion systems that ensure stability, power quality, and harmonic suppression. This paper presents the design, analysis, and optimization of a five-level cascaded H-bridge (CHB) inverter integrated with an LCL filter and controlled by a PI controller using sinusoidal pulse-width modulation (SPWM). This work focuses on enhancing stability and harmonic performance in sustainable energy microgrids through parametric tuning of PI controller gains (Kp, Ki) and comparative analysis with alternative control strategies. Simulation results demonstrate that optimal PI tuning achieves a total harmonic distortion (THD) of 2.8% in grid current, with a robust transient response under dynamic loads. The sinusoidal pulse width modulation (SPWM) technique offers straightforward implementation while supporting compatibility with multilevel inverter topologies, making it scalable for high-voltage applications. Comparative analysis with proportional-resonance (PR) and hysteresis controllers emphasizes the practicality of PI controllers, achieving an effective balance between computational simplicity and control performance. Our proposed system addresses the main challenges of integrating renewable energy and provides a better and more cost-efficient way to enhance microgrid resilience and power quality. Future research should focus on more reliable and hardware-based authentication to transition key findings from the simulation into real-world applications