I NDUSTRIAL P OWER S YSTEMS , I NC RTG & VSG Presentation EGSA Conference Sept. 18, 2006 Alan McDonnell Bill Young Sales Manager President Youtility Inc. Industrial Power Systems Inc. 11 Executive Dr. Hudson, NH 03051 3010 Powers Ave. Jacksonville, FL 32259
VSG – Fixed Speed Comparison • The following slide shows a comparison between the fixed speed power generation model and a variable speed industrial model CAT C32 ACERT, one of their newest electronic engines • Both engines meet EPA Tier 2 emissions
1800 RPM vs. 700-2100 RPM 500 400 Total Fuel (lb-hr) 300 200 100 100 200 400 600 800 1000 Power (kWe)
Fixed Speed Fuel Consumption vs. Variable Speed Maximum Torque Mode 110% 100% Expected Maximum Efficiency Mode 50% 100 200 400 600 800 1000 Output (kWe)
Economical Applications of VSG • The economics of adding the VSG system will be better for applications with low average power demands • Cranes that require full power for only short periods of time while lifting are good candidates • With a VSG installed, the engine will idle most of the time, and increase in speed only when needed
IPS and Youtility • Have designed a system that can be easily retro-fitted to existing RTG Cranes • Several hundred existing cranes in service globally • Youtility supplies electronic equipment, design responsibility and support to IPS • IPS builds necessary electrical equipment, installation and project management
Typical RTG (Rubber Tire Gantry)
Basic VSG Diagram AC Crane AC Supply power feed 290VAC - 36Hz to 480VAC - 60Hz VSG Control 800VDC Variable Speed Generator Ultra -cap 400 - 720VDC
Detailed VSG Diagram Pre-Charge Contactor Rectifier Boost Regulated 800VDC (+) Generator 6.7L 250kVA 200kW 480V Output 153kW 1800RPM AC Inverter N Variable DC Energy Storage (-) Energy Store / Release Chopper control Bypass / Isolation Contactors - Interlocked
Unique Features of Crane Electrical Power Requirements • New Cranes use AC VFDs to power motors, the major loads (90%) • AC VFD consists of a DC rectifier feeding DC power to an AC inverter • Since the VSG also makes DC power, it can be fed directly on a “common DC bus”
VSG with common DC bus 480VAC - 60Hz AC aux. loads Supply 290VAC - 36Hz to 480VAC - 60Hz VSG AC VFDs Control 800VDC Variable Speed Generator Ultra M M M -cap 400 - 720VDC
Detailed crane DC bus unit Pre-Charge Contactor Rectifier Boost Regulated 800VDC DC Bus power connection (+) Generator 6.7L 250kVA 200kW 480V Output 153kW 1800RPM AC Inverter N Variable DC Energy Storage (-) Energy Store / Release Chopper control Bypass / Isolation Contactors - Interlocked
Energy Storage Advantages • Engine produces poor step change power at low speeds • Energy Storage can supply full rated power in less than 4mSec. With DC/DC boost circuit • Energy Storage can reclaim energy that otherwise goes to Dynamic Braking Resistors • Energy Storage can “smooth” the power required from the generator, less peak required…therefore smaller generator • For high cyclic loads, we prefer Ultra-Capacitors over batteries
A Maxwell brand Ultra-Capacitor
Energy Storage Calculations • 48V x 144F each bank • 16 banks in series = 768VDC x 9F • Total energy = ½ * c * V 2 = 2.6MJ • Useable energy = 0.7 x 2.5MJ = 1.75MJ • Need 400kW (peak) – 150kW (engine) = 250kW x 7sec. = 1.75MJ
RTG Crane Expectations • Overall Fuel Consumption reductions of 30% - 50% • Total Emissions reductions of 70% - 90% • Reduce 23L engine to 6.7L engine • Reduce Idling Fuel Consumption from 20+ L/hr. to 2 L/hr . • We predict all future cranes will be VSG in less than 2 years, based on market competition
Other VSG Applications • Most economical for variable load or less than full load applications • Grid Connect, Stand Alone or Parallel Unit Operations • Combined Heat-Power total efficiency for part-load conditions is much improved • High power quality requirement applications
Other VSG System Features • Transformerless output with full unbalanced load capabilities • Synchronous Generator with integral field control, no need to use a different generator • 96%+ pf. on generator, allows higher outputs with full VA rating utilized • Integrated Energy Storage allows full step load changes in ¼ cycle, no freq. deviation
End of Presentation • Bill Young Industrial Power Systems, Inc. • Alan McDonnell Youtility Distributed Power Electronics
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