Multi-Level Inverter Based on STATCOM with PI Controller Optimized for Voltage Stabilization Applications in Distribution Networks

The reactive part of the current distribution system causes adverse effects on the network. These include voltage drops, reduced line capacity, and increased network losses. Distribution networks use static synchronous compensators (STATCOMs) instead of traditional switch capacitor groups to increase voltage stability. This paper aims to enhance STATCOM by employing a hybrid multilevel inverter structure, which reduces the number of electronic power switches used in the design of multilevel inverters. The proposed nine-level inverter consists of eight switches for positive level generation and four switches for polarity changing. The proposed control switching state technique has achieved more fine control for nine distinct voltage levels by effectively controlling the switching states for the hybrid nine-level inverter. The proposed inverter structure has undergone design, simulation, and experimental testing. Additionally, simulations have been used to examine the dynamic performance of a hybrid multilevel inverter implemented on the STATCOM unit. Particle Swarm Optimization (PSO) and Genetic Algorithm (GA) have been employed to determine the optimal gains for the Proportional-Integral (PI) controller. The simulation results of each optimization technique have been studied and verified to determine the optimal gains for STATCOM PI controllers. Furthermore, the comparison is conducted to find the best-utilized optimization methods.