Transcript DC bus for photovoltaic power supplying computing loads

DC bus for photovoltaic power
supplying computing loads
Vincent Flaherty
4th year Electronic Engineering
Project Aims
• The aim of this project is to investigate if the efficiency of
power delivered from a domestic PV installation can be
improved by supplying such DC loads through a DC bus
instead of through an AC grid connection.
Progress to Date
• Research of PV systems.
• Review of power consumption of different loads.
• Review of PV inverters.
Progress to Date
• Investigation and PSPICE simulation of AC/DC
converter.
• Full Wave Rectifier
• Flyback Converter
PV systems
• PV modules convert sunlight to electricity.
• Made from semiconductor materials.
• General efficiency (6 – 20%)
• An ideal solar cell can be modelled using a current
source in parallel with a diode
Power Consumption
• The average power consumption for a range of electrical
devices which drive DC loads.
Appliance
Consumption
LCD Television
213 Watts
Plasma Television
339 Watts
Playstation 3
197 Watts
Xbox 360
187 Watts
Average PC
78 Watts
Nintendo Wii
19 Watts
Wireless Router
7 Watts
[Figure taken from cnet.com]
PV Inverters
• Used to change DC electricity to AC electricity.
• 2 main types used with PV systems.
• Grid-tie inverters.
• Battery backup inverters
• Solar inverters use procedures such as MPPT to deal
with the PV array.
MPPT
• DC/DC converter functions as optimal load for a PV cell.
• MPPT is used by solar inverters to get the most power
possible from a PV array.
• Can be used with or without batteries.
• The benefits of MPPT regulators are greatest during
cold, hazy or cloudy weather.
Fullwave Rectifier
• Used to convert AC to DC.
• Most simple method of conversion.
• Quite easily simulated using PSPICE.
Fullwave Rectifier
Flyback Converter
• DC/DC converter with isolation between input and
output.
• Very similar to Buck-Boost converter.
• Voltage ratios can be multiplied due to turns in
transformer.
• Can operate over a wide range of inputs.
Flyback Converter
Major Challenges
• Finding circuit schematic for AC/DC
adapter.
• Effective simulation of Flyback converter.
Next Steps
• Finalisation of Flyback converter
simulation.
• Investigation and simulation of other
DC/DC converters. (Buck, Boost etc.)
Questions?