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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.
[Figure taken from cnet.com]
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
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.
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.
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.)