DESIGN AND DEVELOPMENT OF ENERGY MANAGEMENT SYSTEM WITH FPGA CONTROL IMPLEMENTATION OF SOLAR GRID-TIED INVERTER

Abstract

With an increased penetration of Distributed Energy Sources (DES) into the electrical network, grid operators face many challenges concerning the stability and power quality of the grid. Traditional inverters are not able to respond to fluctuations in the grid and ultimately result in disconnection. Smart inverters offer advantage of keeping the grid active by making adjustments to control the DES power levels. Advanced grid functions implemented in smart inverters can offer solutions to grid problems through an interactive control between grid operators and DES inverter controllers. Photovoltaic (PV) sources are also subjected to changes in environmental conditions which limit the efficiency of PV output. Inverters play a major role in improving grid quality by deploying advanced control techniques and design topologies to maximize the power from PV arrays and improve grid quality issues. _x000D_ _x000D_ The focus of this thesis is to develop interactive control architecture between local and central controller which will help grid operator send command instruction to smart inverter. It proposes system architecture for building the prototype by using embedded controller such as Field Programmable Gate Array (FPGA) which offers attractive solution in the smart grid system where configurability and upgrades to existing system are required on field. Based on the literature review, different PV technologies and grid-connected inverter topologies are addressed in the inverter design. Several Maximum Power Point Tracking (MPPT) techniques offer solutions to address environmental conditions affecting the PV output. Grid-connected topologies for Voltage Source Inverter (VSI), switching control techniques and the design of grid filters are proposed which improve power quality issues. Phase-locked-loop (PLL) implementation is a key consideration for grid-tied inverter to synchronize inverter output signal with that of the grid signal._x000D_ _x000D_ The experimental results show techniques to analyze the behavior of PV system in LabVIEWTM co-simulation environment which are later implemented in the hardware. Single-stage PV inverter is designed and tested with MPPT control algorithm implemented in FPGA hardware. Advanced grid functions such as configurable voltage ramp rates as set by the grid operator on a host machine (LabVIEW) are later emulated in the hardware. PLL is implemented in hardware where inverter output voltage synchronizes in phase and frequency with that of the grid signal. The developed prototype will serve as a purpose for further research into micro grid area. It would be able to integrate the available DES in the laboratory to create an operational smart grid test bed.

Date of Award	2017
Original language	American English
Awarding Institution	HBKU College of Science and Engineering