Transcript Slide 1

Michael Ikerionwu
4th 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
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