small wind electric systems wind turbine electrical output – electricity from a spinning shaft...
TRANSCRIPT
Small Wind Electric Systems
• Wind Turbine Electrical Output
– Electricity from a spinning shaft
• Balance of Systems
– Types
– Components
First Things First. What does a small wind turbine produce?
• Wild Alternating Current (Wild AC)– “Wild” due to the fluctuating voltage, current and
frequency.– Why is this?
• Most modern small wind turbines are direct drive permanent magnet systems (there are exceptions)
– In most cases the wild AC needs to be rectified.• Conversion of Alternating Current (AC) to Direct Current (DC)
WILD AC DC 120 AC @ 60Hz
Electricity from a Spinning Shaft
http://www.reuk.co.uk/OtherImages/moving-magnet-past-wire-to-make-current.jpg
Click Here for Animation
Why Alternating Current?
• Simplicity of permanent magnets alternators
• This AC power is rectified to Direct Current regardless of battery or grid-tie configuration.
• 3 phase output is most common
http://bp1.blogger.com/_Ist6QgbdKFo/SIsThFlYcTI/AAAAAAAAAGw/-cBy0MQjDvI/s400/5.bmp
Why Three Phase?
• Most effective use of space and materials!
3 Phase Output
(Short) Kill Switch
3 Rectifiers in parallel
Leads to Battery
Axial Flux PM Alternators
http://flyingv.ucsd.edu/nima/Axial_Flux/motor_cad.jpg
Small Wind Systems Small Wind Systems:
• Battery (off-grid) systems
• Grid-Tie with battery backup systems
• Batteryless / Direct grid-tied systems
• Direct Drive Batteryless Systems
Battery (off-grid) systems
Regulation and Conversion
Battery (off-grid) systems
Controller
Off-Grid Hybrid System• Combines multiple DC charging systems
Battery (off-grid) Hybrid system
Controller
Benefits of Hybrid Systems?Wind and solar compliment one another!
400
350
300
250
200
150
100
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Ho
urs
of s
uns
hin
e o
r av
era
ge
win
d p
ower
(W
atts
/m2)
Average wind power
Data from SE Iowa
Hours of Sunshine
PV modules and wind turbine(no generation)
Battery(storage)
Loads(utilization)
PV modules and wind turbine(active generation)
Summer
Winter
Battery(storage)
Loads(utilization)
The Effects of Seasons on Hybrid Power Systems
Grid-Tie with Battery Backup
Controller
Grid-Tie with Battery Backup
• Benefits:
– Potential sale of excess energy– Battery backup during electrical grid failure– Incentives supported
• Downfalls:
– Expensive– Added maintenance (batteries)
Batteryless / Direct Grid-Tie Systems
Controller
• Benefits:
– Sale of excess energy to the grid
– Lower system cost
– Incentives supported
• Downfalls:
– No battery back up. If the grid fails you are left in the dark.
Batteryless / Direct Grid-Tie Systems
Direct Drive Batteryless System
Controller
http://image.made-in-china.com/2f0j00seKTaQUBJEhy/Water-Pump-MKP60-1-.jpg
• Benefits:
– Simplicity
– Lowest in cost (no balance of system needed)
• Downfalls:
– Only power loads when resource is available
– Heating applications require large turbines
Direct Drive Batteryless Systems