Michael Ikerionwu 4 th year Electronic Engineering

Project Aims The aim of this project is to investigate if efficiency of power delivered from a domestic PV installation can be improved by supplying such DC load through a DC bus instead of through an AC grid connection.

Progress till date Review and research on PV panels characteristics and circuit models Review of PV inverters (including MPPT). Review of power consumption of a range of DC loads. Spice simulation of AC/DC converter such as full wave rectifier.

PV Panels PV panels are devices that convert solar energy directly to electricity. Consists of semiconductors poly crystalline silicon and amorphous silicon. Light is absorbed by semiconductors which cause electrons to move resulting in current. Solar cell model with current source and diodes.

PV Panels Efficiency is generally between 6 and 20%. Fossils fuels use to be main source of energy for several generations. The use of PV panels is not viable due to high cost of installation and upkeep of PV modules. Nowadays PV systems are becoming a truly viable option for everyone.

I-V characteristic

PV inverters Used for DC/AC conversion Three different types of inverters: stand alone, grid tie and battery backup inverters. Stand alone – draws DC energy from batteries charged by PV arrays. Battery back up –draw energy from battery and provide back up power during utility. Grid tie – designed to shut down automatically upon loss of utility supply for safety reasons and do not provide backup power. Solar inverters uses MPPT to deal with PV arrays.

Maximum power point tracking High efficiency DC/DC converter converts power by PV cells to voltage or current depending on what it is suitable for. Used to get the maximum power from PV arrays. Advantages is that MPPT regulators can be used during cold and cloudy weather. Can be used with or without batteries.

Power consumption of DC loads

MPPT I-V characteristic

Full Wave rectifier

FWR simulation

Buck converter