AC Coupling Small Wind Turbines
Off-Grid
Original DC Coupled System
48V
4400W
Inverter/Charger (I/C)
740ah Battery
2.5kW Wind
2.5kW Tracked PV
DC Coupled
Pill
Box
DC Coupled
Yurt
Ranch Expansion
Ranch Expansion
 Water Pumping for Cattle Operation
 Bakery & Pico Brewery
At Limits of Original System
DC Coupled
Pill
Box
DC Coupled
Yurt
DC Coupled
Power
House
Bakery
DC Coupled
nd
2
DC Coupled System
48V
8,800W I/C
1,780ah Battery
2.5kW Wind
3.2 kW PV
New System
otherpower.com Workshop
May 2012
Down with the Old/Up with the New
The Road to AC Coupling



The Need to Combine
New and Old System
Large AC Loads
I/C with Frequency
Shifting New to the
Market
AC Coupling
• GTI Latches onto 240VAC-60 Hz Produced from I/C
• Loads & Energy Sources are Coupled More Closely
• Excess Energy is Pushed Back thru I/C to Battery
AC Coupled
Pill
Box
AC Coupled
Yurt
DC Coupled
Power
House
Bakery
DC Coupled
AC Coupled
AC Coupled
Combined AC/DC Coupled System
48V
17,600W I/C
1,780ah Battery
12’ Wind Turbine DC Coupled
12’ Wind Turbine AC Coupled
3.2 kW PV DC Coupled
7.5 kW PV AC Coupled
Magnum Energy PAE
Inverter/Charger
Regulating Strategies
Diversion Loads
Frequency Shift
Monitoring and
Controlling Loads
Diversion Loads
Frequency Shift


Frequency Shift to
60.5 Herz @ 4V
above Absorb....
GTI's go Offline per
UL 1741
Frequency Shift Back
to 60.0 ish Herz @ 4V
below Absorb.....GTI's
Back Online
Monitoring and Controlling Loads
•Domestic Hot Water Pre-Heat
• Radiant in-floor Hot Water Pre-Heat
• Well pump for filling Cisterns
• Heater for battery vault
Too Much Power...Put it to Work
System Equipment
 2 otherpower 12' Wind Turbines 100V & 48V Stator
 16 Trojan IND-6 Batteries 890 Ah
 1 Ginlong 3K GT Wind Inverter
 3 Ginlong 3K GT Solar Inverter
 1 TriStar MPPT Solar Charge Controller
 4 Magnum PAE 4400W-48V Inverter/Chargers 17,600W
 4 TriStar Diversion Load Controller with 17,280W Load
Resistor Heaters
AC Coupling Off-Grid
Disadvantages
• GTI knocked Off-Line when Large Loads Turn on
- Extreme Under/Over Voltage
- Extreme Under/Over Frequency
•Cost?....Maybe
AC Coupling Off-Grid
Advantages
• Increases Turbine Placement Options
• Savings on Conductors
• Large Loads & Energy Sources are Coupled
• Cost?..........Maybe
Observations
• The need for DC
Coupled Wind & Solar
to keep the Micro-Grid
alive
• Higher Resource to
Load Conversion
• 1741 Five minute
Requirement Altered
Project Credits
Robert’s Electric
WindFarmer
King Canyon Buffalo
otherpower.com
Hencey Plumbing
Todd Hanley
APRS World
Roy Rak
marc@windfarmer.us