Fuzzy Logic Control Implementation for Grid-Connected Multilevel Inverter Using FPGA-Based CORDIC-PLL Synchronization

This paper discusses a novel approach to control a grid-connected multilevel inverter using Field Programmable Gate Array (FPGA) implemented Fuzzy controlled Coordinate Rotation Digital Computer Phase-Locked Loop PLL (CORDIC-PLL) system for achieving improved inverter performance in injecting active and reactive power into the grid under changing grid conditions of operation. A seven-level cascaded Hbridge inverter topology is used to reduce total harmonic distortion without the need for large filtering components. The CORDIC-PLL system gives fine phase information for synchronization, while the fuzzy logic controller (FLC) makes adjustment in the output of the inverter by changing amplitude factors of carrier signals and phase angles for power injection control. In this way, experimental results depicted the effectiveness of the proposed system with significant improvements related to power quality and system stability.