A novel transformer-less eleven-level inverter with optimized Buck–Boost controller and minimal switch design for grid-connected PV systems

This study introduces an innovative hybrid power quality system designed to address power quality issues in grid-connected photovoltaic (PV) systems. The system features a transformer-less eleven-level inverter and integrates an optimized Buck–Boost (BBC) controller with an optimized Proportional–Integral–Derivative (PID) controller. The optimized PID controller output drives multiple Pulse Width Modulation (PWM) techniques, including Sinusoidal PWM (SPWM), Staircase PWM, and Trapezoidal PWM, whose performances are compared. The output is processed through a Unified Power Quality Conditioner (UPQC-PQ) to manage active and reactive power. Optimization of the PID and BBC controllers is achieved using a novel hybrid metaheuristic algorithm, Tasmanian Floral Optimization (TFO), which combines Tasmanian Devil Optimization (TDO) with the Flower Pollination Algorithm (FPO). The inclusion of a transformer-less eleven-level inverter with six switches reduces switching losses, while a comparative Total Harmonic Distortion (THD) modulation technique minimizes THD in the output voltage. The proposed system is implemented and evaluated in Matlab/Simulink with comparative analysis showing its superior performance over existing methods. This makes it a highly effective solution for enhancing power quality in grid-connected PV systems.