FPGA based Implementation of Frequency and Phase Matching Technique for Grid Tied Applications

TL;DR

This paper presents an FPGA-based system for real-time frequency and phase synchronization of a grid-tied inverter, demonstrated through simulation and hardware implementation with improved techniques for stability and simplicity.

Contribution

The paper introduces a novel FPGA-controlled grid tie mechanism with an improved Zero Crossing Detection and a simplified PLL for stable real-time synchronization.

Findings

Successful hardware implementation on solar-powered inverter

Reliable real-time phase and frequency matching achieved

Enhanced stability with simplified algorithms

Abstract

A grid tied inverter converts DC voltage into AC voltage, while synchronizing it with the supply line phase and frequency. This paper presents an efficient, robust, and easy-to-implement grid tie mechanism. First, the grid tie mechanism was simulated in software using LabVIEW and Multisim. Then, the whole system was practically implemented on hardware. A prototype hardware was developed to produce AC voltage from solar panels. Phase and frequency of the generated voltage were synchronized with those of a reference sinusoidal signal. The synchronization mechanism was digitally implemented on an FPGA, which also controlled the whole system. We achieved real time frequency matching with an improved Zero Crossing Detection (ZCD) technique. Phase matching was also achieved in real time using a modified Phase Locked Loop (PLL) algorithm, which retains stability while being simpler than the general PLL algorithm. Experiments demonstrated that the proposed grid tied system reliably synchronized the phase and frequency of the voltage generated by the implemented hardware with those of the reference grid voltage.