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© 2013 Eaton Corporation. All rights reserved. This is a photographic template – your photograph should fit precisely within this rectangle. Transformerless.

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Presentation on theme: "© 2013 Eaton Corporation. All rights reserved. This is a photographic template – your photograph should fit precisely within this rectangle. Transformerless."— Presentation transcript:

1 © 2013 Eaton Corporation. All rights reserved. This is a photographic template – your photograph should fit precisely within this rectangle. Transformerless UPS Concepts and Capabilities for Large System UPS Power Quality Division

2 2 2 Eaton Confidential »It may be the single most important feature that saves the customer from dropping their load Inherent Redundancy Option Next Generation Reliability Data center efficiency surveys reveal that UPSs are often under loaded at 50% or lower End users purchasing a 9395 with more than one UPM can choose the inherent redundancy option. Anytime the load is below (#UPMs-1) capacity, it is automatically redundant

3 3 3 Eaton Confidential 275 kVA Redundant 550 kVA Redundant On-site upgrade Flexible, Scalable, Upgradeable Add another 275 kVA in the field for redundancy, or for capacity Simply choose an ISBM sized for future growth Leave space on the left side Enables flexibility for future changes in load demands, and new requirements for higher reliability On-site upgrade

4 4 4 Eaton Confidential 1100 kVA Modular UPS 1100 kVA ISBM 275 kVA UPM kVA capacity

5 kVA Inside View: 400/480V 3 UPMs in one shipping split Top or bottom cable entry in ISBM shipping split Front-access only Static bypass, input breaker

6 © 2013 Eaton Corporation. All rights reserved. This is a photographic template – your photograph should fit precisely within this rectangle. Large System Transformerless Architecture Technical Details

7 7 7 First, A Little History…… Eaton Confidential

8 8 8 Technology and Efficiency over the Years IGBT UPS 85 to 90% SCR UPS 75 to 80% Transformer- less UPS 90 to 95% Hybrid UPS Multilevel converters ~97 % ES/Eco mode 98 to 99+% Transistor UPS 80 to 85% 75% 100% Full Load Efficiency Harmonic mitigation & load balance 98 to 99+% Technology advances continue to boost UPS efficiency

9 9 9 Transformerless Advantages Smaller system size and weight Transformers are big contributors to these key factors PWM Rectifier provides high input PF and low THD over wide line and load range Doesnt require large input harmonics filters Efficient Operation No transformer power losses and optimized DC Link voltage Uses IGBT converters, all of identical make-up Standardizes on power circuits, components, and support Maintains an optimally high DC buss for the inverter Significant reduction in current handling for inverter components Reduce inrush current and improved generator compatibility Technology current IGBT performance/cost has steadily improved over the past 10 years Green and Sustainable Reduction in iron, copper, and varnish usage

10 10 Simplified SCR UPS Schematic Your Fathers UPS…. Input Transformer and 6-Pulse Rectifier Force-commutated Inverter and Output Transformer Now Replaced by Transformerless, IGBT-based Power Converters, for High Efficiency and Power Density

11 11 Active (IGBT) Rectifier Current Waveform Low THDi, High Power Factor Site Friendly and Generator Compatible

12 12 Transformerless UPS Allows Significant Size and Weight Reduction (Below – 275 & 300KVA Examples)

13 13 ISBM SectionUPM Section Inside the Transformerless UPS X-Slot communications Power Xpert Web Card 8-line backlit LCD Input circuit breaker option Top- or bottom- entry Static bypass – continuous duty Base with inter- unit cabling Double-conversion topology converter/ inverter section Redundant power supplies Redundant fans Contactor output UPM easy service disconnect UPM Section

14 14 Transformerless Disadvantages No galvanic isolation Battery is not isolated No transformer based common mode noise isolation Requires specialized Hi Z battery fault detection equipment Higher DC Link voltage (when compared to SCR front end) Neutral phase leg required for L-N loads (WYE output)

15 15 Eaton Confidential Transformerless Topology Simplified Schematic Diagram IGBT rectifier front end

16 16 Hybrid and Air-core Inductor DesignsLess Space, Weight, Plus Cooler operation

17 17 Eaton Confidential Transformerless Topology DC-DC Converter Bidirectional battery converter charges battery, and regulates the DC link when on- battery. Makes the battery voltage independent of the DC link Removes inverter efficiency penalty caused by battery voltage swing

18 18 The Battery Converter and Why Removes inverter efficiency penalty (current penalty) caused by battery voltage swing Makes the battery voltage independent of the DC buss voltage Accommodates a broader range of nominal battery voltage configurations Provides system flexibility with many other DC sources including flywheels, ultra-caps, PV, etc.

19 19 Eaton Confidential Transformerless Topology 3 or 4-wire Inverter IGBT inverter with neutral modulation

20 20 Eaton Confidential Transformerless Efficiency Efficiency = Pout / (Pin + Ploss) Ploss is comprised of: IGBT switching losses and conduction losses Magnetics copper and core losses transformer losses Switching losses are directly proportional DC Link voltage Switching frequency For the Transformerless UPS Modulating the N leg reduces harmonic content and allows for a reduction in switching frequency Adding a zero sequence to all of the PWM vectors causes the DC link to closely track the required three phase voltage space and effectively lowering the required DC Link Eliminating the transformer removes one more source of losses

21 21 Eaton Confidential UPS Fault Tolerance UPS is evaluated for performance under different external fault situations: battery faults, input source faults, output (load) faults, as well as its response to internal fault conditions Fault Tolerance - expected behavior No load loss No single point of failure Types of fault tolerant behavior Unit remains on-line Unit transfers to bypass Unit announces/alarms condition

22 22 Eaton Confidential More on Eaton Transformerless Topology The myth The lack of an output transformer decreases the overall reliability of the system. The transformer helps the inverter handle faults, protecting it from high fault currents Similarly, the transformer protects loads from inverter faults, preventing them from having DC voltage applied to them when an inverter fails The Truth Low-frequency inverters, driven by low-bandwidth analog or rudimentary microprocessor controls, do benefit from the increased impedance presented by either a large inductor or a transformer in the output of the inverter, as slow response controls requires the currents rate of rise to be slowed down in the event of a fault Transformerless topology has its foundation on: High-frequency PWM power conversion High-bandwidth advanced DSP controls, with sampling rates above 33 KHz (once every 30 microseconds) High-bandwidth controls do not get any benefit from additional impedance on the output of the inverter – on the contrary, they rely on instantaneous information to maintain best performance conditions

23 23 Eaton Confidential Handling output faults - If bypass is available, let the bypass try to clear the fault - High-frequency PWM and small inductor requires fast signal sensing - … and can quickly control power train to expedite transfer to bypass - if bypass is not available, the inverter supplies 300ms of limited fault current

24 24 Eaton Confidential Output Fault Test Single KVA 480V UPS 480Vin/480 Vout Common Battery (8) 1085 Cabinets 475W/240 Cell 98% Load Bypass Not Avail (therefore no bypass intervention, all inverter) Fault applied output Ph B to ground Test Results: Unit services short for 300mS without damage or without tripping breakers Waveform: voltages are 200V/div and fault current is 4000A/div

25 25 Eaton Confidential Handling input faults… - Similar to output faults, high- frequency PWM and small inductor requires fast signal sensing - … and can quickly control power train to expedite transfer to battery mode

26 26 Eaton Confidential Input Fault Test Single KVA 480V UPS 480Vin, 480Vout Battery (2) 1085 Cabinets 475W/240 Cell 100% Load Fault applied at UUT input Ph B to ground Test Results: Input breaker trips (part of test setup) and unit drops to battery Waveform: voltages are 250V/div and fault current is 1200A/div

27 27 Eaton Confidential Protecting the Mission Critical Load… - If inverter IGBT fails short, fuses in DC link will open. IGBTs will eventually open too. - Load will never see DC voltage at the AC lines

28 28 Eaton Confidential IGBT Internal Fault Test Single KVA 480V UPS 480Vin/480 Vout Common Battery - (8) 1085 Cabinets 475W/240 Cell 100% Load Short circuit applied collector to emitter, Rectifier IGBT, Q1, phase B on UPM1 Test Results: Unit transfers to battery. Alarm Check Rectifier PM1 is enunciated. Waveform: voltages are 400V/div and fault current is 1000A/div IGBTS Q1 and Q3 failed Fuses F1 and F4 open

29 29 Eaton Confidential Battery Isolation Battery galvanic isolation in the UPS can provide a false sense of security, and should not be depended on as a safety feature Battery terminals should be treated with the same caution and respect given to any AC terminal in the system If a UPS only has an input transformer, then the battery is not floating An output transformer is required to isolate the battery from the energized output bus Concerns about safe Service associated with hot battery terminals should be addressed by: Using plastic or rubber battery terminal covers Service procedures or guidelines that require all battery maintenance to include the precaution of opening battery circuit breakers Measures that are much less expensive than transformers The absence of battery isolation is not detrimental to the UPS completing its stated mission: to protect the critical bus

30 30 Eaton Confidential Battery Isolation Battery galvanic isolation in the UPS can provide a false sense of security, and should not be depended on as a safety feature Battery terminals should be treated with the same caution and respect given to any AC terminal in the system If a UPS only has an input transformer, then the battery is not floating An output transformer is required to isolate the battery from the energized output bus Concerns about safe Service associated with hot battery terminals should be addressed by: Using plastic or rubber battery terminal covers Service procedures or guidelines that require all battery maintenance to include the precaution of opening battery circuit breakers Measures that are much less expensive than transformers The absence of battery isolation is not detrimental to the UPS completing its stated mission: to protect the critical bus

31 31 Common Mode Noise Isolation Data center and communications equipment today is immune to common mode noise due to improved power supply designs Its a good idea to confirm if galvanic isolation is really needed by the critical load Common mode noise isolation as a requirement This requirement is limited to some medical and industrial/processing equipment Often times a downstream PDU or IDC can be used to support this requirement PDU can be located closer to the critical load where the noise isolation is most important

32 © 2013 Eaton Corporation. All rights reserved. This is a photographic template – your photograph should fit precisely within this rectangle. What other cool stuff can we do, once the transformer is eliminated?

33 33 Eaton Confidential Variable Module Management System (VMMS) DC AC DC AC DC Load < 440KVA UPM not required to power load Remains Hot Tied to Critical Bus Assumes load in < 2ms when required AC DC

34 34 Eaton Confidential 3 X 825KVA Parallel System with VMMS ISBMISBM UPMUPM UPMUPM ISBMISBM UPMUPM UPMUPM ISBMISBM UPMUPM UPMUPM UPMUPM UPMUPM Maintain UPM Loading of 80% to maximize efficiency UPMs in VMMS-Mode are available to assume load in less then 2ms to respond to load changes. UPMUPM

35 35 Eaton Confidential 3X825 Parallel System Efficiency

36 36 Eaton Confidential Energy Saver System Maximum Efficiency Tracking Highest availability with 99% efficiency for a wide load range 85% reduction in losses compared to legacy transformer-based UPS Continuous power tracking and proprietary DSP algorithms combined with transformerless topology ensures critical loads are always protected Regular 92 Efficient 95 Premium 99 EFF Premium 99 Efficient 95 Regular 92 Savings based on 1MW at $0.1/Kw-hr

37 37 Eaton Confidential ESS Surge Response ESS keeps the rectifier and inverter filters tied to the critical load bus, while the storage capacitors and power train semiconductors act as a peak tracking clamp minimizing spikes and noise attenuating line surges

38 38 Eaton Confidential ESS with VMMS Double Conversion > 3% efficiency improvement over existing double conversion only approach ESS 99% efficiency for 50 % of the system load VMMS >93% efficiency for 50% of the system load Double Conversion backup for 100% of system load VMMS on B Single or Dual Source ESS 99% Efficiency ESS on A A B 50% of Load VMMS > 93% Efficiency

39 39 Eaton Confidential Questions

40 40 Eaton Confidential Disclosed under terms of Non-disclosure Agreement between Eaton and TBD

41 41 Eaton Confidential 3rd Party Ground Current Sensing Device Mountable on the battery rack or on the wall in the battery room Located where its needed in the battery room to warn maintenance technicians of a fault Detectors can latch the alarm condition to capture fault conditions that may be temporary as when an electrolyte/spill evaporates The detectors ground leakage current level is settable and can be matched to requirements specific to a site Detectors work with wet cell and VRLA battery configurations


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