Date of Award

1-1-2018

Document Type

Thesis

Degree Name

Master of Engineering (Research)

Department

Electrical & Electronic Engineering

First Advisor

Joe Connell

Second Advisor

Martin Hill

Third Advisor

Noel Barry

Abstract

The objective of this work is to design and build a novel topology of a micro-inverter to directly convert DC power from a photovoltaic module to AC power. In the proposed micro-inverter, a structure with two power stages, which are DC/DC and then DC/AC converters, is used. A novel MPPT algorithm is implemented and evaluated in the DC/DC converter to optimize the solar panel energy production. The new method operates with an efficiency of 97.9%, which is a 1% improvement on the standard method, and a response time of <0.2s. The DC/AC inverter converts DC power into AC power at 50Hz, with the ability to independently supply active and reactive power. Between the DC/DC converter and the inverter is an energy storage buffer to balance short-term power supply and demand and increase the robustness of the system. The energy buffer is a Li-ion battery at 30V/1Ah. This novel energy buffer gives additional flexibility for inverter grid support and is a useful component in the inverter design and control system proposed in this project. A modification of designing the inductor and transformer using Litz wires is also mentioned. The core using Litz wires may reduce the Eddy current effect and is 15% smaller than the coil using a single conductor.

In this research, the following approach is taken. A literature review was conducted, to identify potential converter topologies. A topology for both converters was selected by comparison of performance through simulations. Maximum Power Point Tracking algorithms were also investigated, to select an appropriate control scheme. A design for two converters was then performed, leading to a prototype for experimental verification

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

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