UPS-Tech rev 5.3 1 Show information... Navigation links: Move the cursor across the links and wait for the “hand” symbol - then click left mouse key. Click.

UPS-Tech rev 5.3

1

Show information...Show information...

•Navigation links: Move the cursor across the links and wait for the “hand” symbol

•- then click left mouse key.

•Click the APC logo link to jump back to the previous showed slide.

•Click the left margin area to jump to the index - “UPD Technology Index”

•From the index -links, you may jump to any other subjects.

• - use the APC-return logo to return to the index slide again .

•A star * above the slide number indicates available slide-note in mode “Showing Notes”

UPS-Tech rev 5.3

2

UPS TechnologyUPS Technology & &

Delta-Conversion Delta-Conversion

UPS-Tech rev 5.3

3

UPS Technology index...UPS Technology index...

HeadHead lineslinesOption: Select and jumpOption: Select and jump to a specific subject...to a specific subject...

Power interruptions

What is a UPS ?

The different types of UPS systems

Delta-Conversion tech. and performances

Load-step pictures

Power flow

Delta-Conversion main components

Delta-Conversion circuit diagram

Questions...

UPS-Tech rev 5.3

4

Power Power interruptionsinterruptions

Power interruptions

HeadHead lineslinesPower interruptions

What is a UPS ?



Load-step pictures

Power flow



Questions...

UPS-Tech rev 5.3

5

Power Quality - DistributionPower Quality - Distribution

Liberalization of the power market - will result in decreasing power quality

“It´s a long way” from

power producer to end user

Power transport

disturbances: Power station break down Transformer switches Distribution switches High voltage power net Wind generators Net corruption Net voltage regulation Flash of lightning Gales and Damages by water ……..

Power interruptions

UPS-Tech rev 5.3

6

Power quality is also influenced by...Power quality is also influenced by...

Few of many disturbances...

Powerdisturbances

UPS

Motors

Power interruptions

UPS-Tech rev 5.3

7

meansmeans……

• System DowntimeSystem Downtime

• Black screenBlack screen

• System Lock upSystem Lock up

• Lost or corrupted dataLost or corrupted data

• Keyboard lock-upKeyboard lock-up

• Hardware corruptionHardware corruption

Poor power quality...Poor power quality...

- on power critical - on power critical applications...applications...

Power interruptions

+ +

UPS-Tech rev 5.3

8

Power interruptionsPower interruptions

Power break down

Low voltage

High voltage

Power interruptions

UPS-Tech rev 5.3

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Power interruptionsPower interruptions

Spikes

Combined interruptions

Harmonics

Power interruptions

UPS-Tech rev 5.3

10

““The perfect wave”The perfect wave”

- the optimal power condition...- the optimal power condition...

ConstantConstant

CleanClean

PowerPower

Power interruptions

more solutions

available…

few

“close to perfect”

UPS-Tech rev 5.3

11

What is a What is a UPS UPS


What is a UPS ?



Load-step pictures

Power flow



Questions...

UPS-Tech rev 5.3

12

200V - 250 V

What is a UPS ?What is a UPS ?

What is a UPS ?

230V +/-1%

S I L C O N G R O U P

A UPS ensures...A UPS ensures...

Up-timeUp-time

Data SafetyData Safety

Hardware protectionHardware protection

UPS … means UUn-interruptible PPower SSupply

UPS-Tech rev 5.3

13

Requirements to your UPS...Requirements to your UPS...

UPS• Lowest installation cost• No electrical disturbances• Resistive load - PF1

• Low weight• Small foot print

• Constant clean power• Lowest electricity bill

• Low heat dissipation• Low audible noise

What is a UPS ?

UPS-Tech rev 5.3

14

Consider your UPS requirementsConsider your UPS requirements

UPS• Lowest installation cost• No electrical disturbances• Resistive load - PF1

• Low weight• Small foot print

• Low heat dissipation• Low audible noise

What is a UPS ?

• Size of cable and fuses ?• Mains repercussion - EMC ?• Phase compensation ?

• Efficiency• Cooling requirement more solutions

available…

few

“close to perfect”

• Constant clean power• Lowest electricity bill

• The technology• Efficiency• Service organization• Supplier reputation

• The technology• Efficiency and cabinet

UPS-Tech rev 5.3

15

UPS InstallationUPS InstallationWhat is a UPS ?

Mains Supply Distribution Panel

Loads

SBP

UPS

Input Panel

Diesel Generator

UPS-Tech rev 5.3

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UPS technologies...UPS technologies...

Standby system Line interactive

Double conversion

What is a UPS ?

UPS-Tech rev 5.3

17

UPS technologies...UPS technologies...

MG

Rotary conversion

Single conversion 1st

Single conversion 2nd

Delta-Conversion

What is a UPS ?

UPS-Tech rev 5.3

18

HeadHead lineslines

The different typesThe different typesof UPS systemsof UPS systems

Power interruptions

What is a UPS ?



Load-step pictures

Power flow



Questions...

UPS-Tech rev 5.3

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UPS systems of today is more than...UPS systems of today is more than...

On-line (working)On-line (working)

Off-line (sleeping)Off-line (sleeping)““Standby”Standby”

UPS systems

*

UPS-Tech rev 5.3

20

Different UPS topologies...Different UPS topologies...

...m

ost c

omm

on Standby Line Interactive Standby On-Line Hybrid Standby Ferro Double Conversion On-Line Delta Conversion On-Line

Identifying the topologies - is to understand the differences

UPS systems

*

UPS-Tech rev 5.3

21

The Standby UPS...The Standby UPS...

SurgeSuppressor Filter

Battery

+-

Inverter

D C

A C

BatteryCharger

AC/DC

LoadTransferSwitch

0 - 0.5 kVA

•Uses battery during brownouts•Impractical over 2kVA

•High efficiency•Compact•Low cost

Benefits: Limitations:

UPS systems

*

UPS-Tech rev 5.3

22

The line Interactive UPS...The line Interactive UPS...

Battery

+-

TransferSwitch

Inverter

D C

A C

Load

Charging (normal)

Discharging (Power fail)

0.5 - 3 kVA

•Impractical over 5 kVA•High reliability•High efficiency•Good voltage conditioning


UPS systems

*

UPS-Tech rev 5.3

23

Standby On-line Hybrid...Standby On-line Hybrid...

Rectifier

Combiner

Load

Inverter

D C

A C

BatteryCharger

AC/DC

StandbyDC to DCConverter

D C

D C

Battery

+-

0.5 - 5 kVA

•Low efficiency•Low reliability•High cost•Impractical over 5kVA

•Excellent voltage conditioning


UPS systems

*

UPS-Tech rev 5.3

24

The Standby-Ferro UPS...The Standby-Ferro UPS...

Battery

+-

Inverter

D C

A C

BatteryCharger

AC/DC

Load

TransferSwitch

Transformer

3 - 15 kVA

•Low efficiency•Unstable in combination with someloads and generators



UPS systems

*

UPS-Tech rev 5.3

25

The Double Conversion The Double Conversion On-Line UPS...On-Line UPS...

•Low efficiency•Impractical under 5kVA

•Excellent voltage conditioning•Ease of paralleling


*

SurgeSuppressor Filter

Battery

+-

Inverter

D C

A C

BatteryCharger

AC/DC

Load

5 - 5000 kVA

UPS systems

UPS-Tech rev 5.3

26

The Delta ConversionThe Delta ConversionOn-Line UPS...On-Line UPS...

•Impractical under 5kVA

•High efficiency•Excellent voltage conditioning•Ease of paralleling •Compact


UPS systems

*

SurgeSuppressor

Inverter

D C

A C

Load

Battery

+-

5 - 5000 kVA

DeltaConverter

Filter

UPS-Tech rev 5.3

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Comparing UPS characteristics ...Comparing UPS characteristics ...

Practical

power range(kVA)

Voltage conditioning Cost per VA Efficiency

Inverter always

operating

Standby 0 - 0.5 Low Low Very High No

Line interactive 0.5 - 3 Design depending Medium Very High Design

depending

Standby On-Line Hybrid 0.5 - 5 High High Low Partially

Standby Ferro 3 - 15 High High Low No

Double Conversion On-Line 5 - 5000 High Medium Low Yes

Delta Conversion On-Line 5 - 5000 High Medium High Yes

Char.Technique

The unique combination...

UPS systems

*

UPS-Tech rev 5.3

28

Comparing UPS characteristics ...Comparing UPS characteristics ...

APC´s FindingsChar.

Technique LimitationsBenefitsUsed in APC

products

•Best value for personal workstations

•Uses battery during brownouts•Impractical over 2kVA

•Low cost•High efficiency•Compact

•Back-UPSStandby

•High reliability•Ideal for rack or distributed servers•For and harsh power environment

•Impractical over 5kVA

•High reliability•High efficiency•Good voltage conditioning

•Smart UPS

Line interactive

•Good reliability•Good voltage conditioning

•Low efficiency•Low reliability•High cost•Impractical over 5kVA


•Not used by APC

Standby On-Line Hybrid

•Limited application due to low efficiency•Instability problems•N+1 On-Line design offers better reliability

•Low efficiency•Unstable in combination with some loads and generators


•Not used by APC

Standby Ferro

•Well suited for N+1 designs

•Low efficiency•Impractical under 5kVA

•Excellent voltage conditioning•Ease of paralleling •Symmetra

Double Conversion On-Line

Delta Conversion On-Line

•Well suited for N+1 designs•Outstanding Return Of Investment benefit, at high power plant

•Impractical under 5kVA

•High efficiency•Excellent voltage conditioning•Ease of paralleling •Compact

•DP300E

*

UPS-Tech rev 5.3

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HeadHead lineslines

Delta-Conversion Delta-Conversion tech. and tech. and

performancesperformances

Power interruptions

What is a UPS ?



Load-step pictures

Power flow



Questions...

UPS-Tech rev 5.3

30

““Close to perfect” solutionClose to perfect” solution

...is Combining advantages

from

existing

technologies

Delta-Converter

Battery

Load

Mains

Delta-Conversion...Delta-Conversion...

On-line Delta-ConversionOn-line Delta-Conversion

• On line technologyOn line technology

• Pure sinusoidal output powerPure sinusoidal output power

• Maximum protection against spikes, Maximum protection against spikes,

surges, sags and power break downsurges, sags and power break down

• Clean output at all time Clean output at all time

• Optimum system efficiencyOptimum system efficiency

• Full rated output available in kWFull rated output available in kW

• Input power factor corrected to 1Input power factor corrected to 1

• No mains repercussionsNo mains repercussions

• Small footprintSmall footprint

• 200% overload capability 200% overload capability

• Energy losses < 4%Energy losses < 4%

UPS-technologies

UPS-Tech rev 5.3

31

Delta-ConversionDelta-ConversionOn-Line and high efficiency…?On-Line and high efficiency…?

what´s the trick…?

UPS-technologies

UPS-Tech rev 5.3

32

The Energy Saving Trick...The Energy Saving Trick...

Double conversion

4. Floor

5. Floor

Delta Conversion

4. Floor

5. Floor

UPS-technologies

UPS-Tech rev 5.3

33

Who makes the trick...Who makes the trick...

The APC-Delta Conversion Technology is today protected by patents.

APC is the exclusive supplier of this technology - DP300E

The technology is not likely to be available from many other UPS-suppliers for some time

UPS-technologies

UPS-Tech rev 5.3

34

Silcon DP300E - power flowSilcon DP300E - power flow

Mains input

Battery

DeltaInverter

MainInverter

Regulating the delta, ± diff. in/out

1. Normal operation

2. Regulated operation

3. Battery operation

4 Recharge battery

Load

UPS-technologies

UPS-Tech rev 5.3

35

Diesels Best Friend...Diesels Best Friend...

100 kW

DIESEL

Silcon DP300E

130 kVA

No harmonicsAlmost same size as UPS

100 kVA

DIESEL

LegacyUPS

300 - 500 kVA

Harmonics3-5 times oversized

UPS-technologies

UPS-Tech rev 5.3

36

Diesels Best Friend...Diesels Best Friend...

Diesel / DP300E installationMains Supply

Diesel Generator

Input Panel

DP310E - DP340E

SBP Distr. Panel

Loads

UPS-technologies

UPS-Tech rev 5.3

37

Delta-conversionDelta-conversionand single-conversion

Smaller diesel generatorcan be used due to:

Power factor correctedregardless of load

Soft start – no load stepfor the generator

UPS: DP3480E with 480 kW load

Diesel Generator:625kVA/500kW

CH 1: Input VoltageCH 2: Input CurrentCH 3: Output VoltageCH 4: Output Current

(100% SMPS load)

CH 1: Input Current (0-100%) during soft startCH 2: Frequencyvariations on diesel generator during soft start.

CH1CH2

CH3CH4

CH1

CH2

21

1

2

Diesel GeneratorDiesel Generator

UPS-technologies

UPS-Tech rev 5.3

38

Delta-conversionDelta-conversion& single-conversion

1.The load is protectedagainst mains sideharmonics

2.Harmonics from unlinear (SMPS) load are filtered out (not fed back to themains)

CH 1: Input VoltageCH 2: Output Voltage

CH 1: Input VoltageCH 2: Input CurrentCH 3: Output VoltageCH 4: Output Current

(100% SMPS load)

CH1CH2

CH3CH4

CH1

CH2

Two way filterTwo way filter

UPS-technologies

UPS-Tech rev 5.3

39

UPS comparative analysis...UPS comparative analysis...

Delta-conversion UPSDelta-conversion UPS

Single conversion UPSSingle conversion UPS

Double conversion UPSDouble conversion UPSTypical 30% input current distortion

No input current distortion Complies to G 5/3 and future norms

1 = Input voltage2 = Input current

1

2

1

2

2

1

UPS-technologies

UPS-Tech rev 5.3

40

Silcon DP300E: 10 - 480 kVA 3-phaseSilcon DP300E: 10 - 480 kVA 3-phase

External Batteries

External Batteries

Built-in Batteries

UPS-technologies

UPS-Tech rev 5.3

41

Comparative conclusionComparative conclusion

True no-break protection Yes Yes Yes

Capability of running SMPS load without derating Yes Yes Yes

True 2-way filter function Yes Yes Yes

Sinusoidal input current No > 30% distortion

Optional Yes

Unity input power factor Optionalbut expensive Optional. Yes

Energy losses, large systems> 10 kVA <100 kVA > 8 - 12% < 5% < 4%

Energy losses, large systems> 100 kVA > 6.5 - 10% < 4% < 4%

Energy losses, small systems< 10 kVA >10 - 15% < 8% < 5%

Basic propertiesDouble Double conversionconversionUPSUPS

Single Single conversion conversion UPSUPS

Delta Delta conversion conversion UPSUPS

Comparative chart

UPS-technologies

UPS-Tech rev 5.3

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HeadHead lineslines

DP300E -DP300E - load step pictures load step pictures

Power interruptions

What is a UPS ?



Load-step pictures

Power flow



Questions...

UPS-Tech rev 5.3

43

DP300E - Load StepDP300E - Load Step

Input voltage

Output voltage

Input current

Output current

1

100%load step 0%

Load step pictures

UPS-Tech rev 5.3

44

DP300E - Load StepDP300E - Load Step

Input voltage

Output voltage

Input current

Output current

load step 100% 0%

2

Load step pictures

UPS-Tech rev 5.3

45

DP300E - Short CircuitDP300E - Short Circuit

Input terminals - short circuit

3

Input voltage

Output voltage

Input current

Output current

Normal operation to battery operation

Load step pictures

UPS-Tech rev 5.3

46

DP300E - Short CircuitDP300E - Short Circuit

Output terminals - short circuit

4

Output voltage

Output current

- fuse clearing in battery operation

Load step pictures

UPS-Tech rev 5.3

47

HeadHead lineslines

Power FlowPower Flow analysis... analysis...

Power interruptions

What is a UPS ?



Load-step pictures

Power flow



Questions...

UPS-Tech rev 5.3

48

Power Flow analysis...Power Flow analysis... nominal mains voltagenominal mains voltage

0%Mains input

Battery

DeltaInverter

MainInverter

0%

Voltage 100%

Current 100%

Power 100%

100%

100%

100%

100%

100%

100%

Power flow

UPS-Tech rev 5.3

49

Power Flow analysis... Power Flow analysis... -15% mains voltage -15% mains voltage

Power flow

Voltage 85%

Current 115%

Power 100%

100%

115%

115%

100%

100%

100%

15% 15%

15%

Mains input

Battery

DeltaInverter

MainInverter

UPS-Tech rev 5.3

50

Power Flow analysis... Power Flow analysis... + 15% mains voltage + 15% mains voltage

Power flow

Voltage 115%

Current 85%

Power 100%

100%

85%

85%

100%

100%

100%

15% 15%

15%

Mains input

Battery

DeltaInverter

MainInverter

UPS-Tech rev 5.3

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Power Flow analysis... Power Flow analysis... battery charging battery charging

Power flow

Voltage 100%

Current 110%

Power 110%

100%

110%

110%

100%

100%

100%

10%0%1

0%

Mains input

Battery

DeltaInverter

MainInverter

UPS-Tech rev 5.3

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HeadHead lineslines

Delta-Conversion Delta-Conversion main componentsmain components

Power interruptions

What is a UPS ?



Load-step pictures

Power flow



Questions...

UPS-Tech rev 5.3

53

DP300E principle diagramDP300E principle diagram

Main components

Load

Main inverterDelta inverter

UPS-Tech rev 5.3

54

Main inverter:4 Quadrant Pulse-Width Modulated Inverter

• Controls the output voltage• Charge the batteries • Supplies the load during Battery operation

Delta-inverter

Load

Mains input

Main inverter

Delta-ConversionDelta-ConversionMain inverterMain inverter

Main components

UPS-Tech rev 5.3

55

Delta-ConversionDelta-ConversionDelta inverterDelta inverter

Delta-inverter Load

Mains input Main inverter

Delta inverter:4 Quadrant Pulse-Width Modulated Inverter

• Controls the input current• Controls the battery charging • Makes up for any difference between in- and output voltage• Regulates the input Power factor

Main components

UPS-Tech rev 5.3

56

Delta-ConversionDelta-Conversioncontrol loopscontrol loops

Main components

Delta-inverter Load

Mains input

Battery

Main inverter

V out senseV bat. sense

Feed back loop for battery charging and input current regulation.Controls the pulse width modulation for the Delta-inverter.

Feed back loop for output voltage regulation.Controls the pulse width modulation for the Delta-inverter.

Load

UPS-Tech rev 5.3

57

Delta-ConversionDelta-ConversionBasic configuration:Basic configuration:

Basic configuration:

•4Q-PWM Inverter is capable of distribute energy in either forward or reverse direction. Meaning that theinverter can work as a charger as well.

•In the UPS we use the fly-back diodes to pass energy to the batteries.

V out

Iout

Half-bridge 4Q-inverter

Iout

Vout3. Inverter

1. Inverter

2. Charger

4. Charger

4Q Pulse-Width Modulated Inverter

Main components

UPS-Tech rev 5.3

58

Delta-Conversion Delta-Conversion Forward mode/Inverter modeForward mode/Inverter mode

Forward mode/Inverter mode• The current is flowing out of the inverter • The inverter is building the sinusoidal output voltage,

the inverter operates in Q1 and Q3 • The switching of the inverter is controlled by a control loop.

The control loop is sensing the output voltage and compares it to the

reference, any difference will make changes in the PWM switching

signals, to make corrections very quick.

V out

Iout

Half-bridge 4Q-inverter

Iout

Vout3. Inverter

1. Inverter

2. Charger

4. Charger

4Q Pulse-Width Modulated Inverter

Main components

UPS-Tech rev 5.3

59

Delta-ConversionDelta-ConversionReverse mode/ rectifier modeReverse mode/ rectifier mode

V out

Iout

Iout

Vout3. Inverter

1. Inverter

2. Charger

4. Charger

Reverse mode/rectifier mode• The current is flowing in to the inverter

• The inverter is still building the sinusoidal output voltage, the inverter operates in Q2 and Q4

• The switching of the inverter is controlled by the same control loop, as in forward/inverter mode.

• The current is now flowing in the fly-back diodes to the batteries

Half-bridge 4Q-inverter 4Q Pulse-Width Modulated Inverter

Main components

UPS-Tech rev 5.3

60

Main Inverter

• Constant voltage regulation

• The output voltage is kept to the reference

• Basically it is a PI-regulation, where the

actual value is compared to the reference.

The result is given to the controller, which

is adjusting the voltage.

• The constant voltage control results in a low

Internal impedance.

4 Q Pulse-Width Modulated Inverter

Main Inverter

PWM

Output voltage ref.

Delta-ConversionDelta-ConversionMain Inverter Main Inverter

Main inverterMain components

UPS-Tech rev 5.3

61

Delta Inverter

Constant Current regulation

As the Inverter can work with constant voltage It can operate with constant current.

• The Current is kept to the reference • Basically it is a PI-regulation, where the actual value is compared to the reference. The result is given to the Controller, which is adjusting the Current.

• The reference is calculated according to the load and the charge level of the batteries

•The constant current regulation results in a high Internal impedance.

4 Q Pulse-Width Modulated Inverter

Delta Inverter Battery

PWM

Battery voltage ref.

Input current ref.

Delta-inverter

Delta-ConversionDelta-ConversionDelta InverterDelta Inverter

Main components

UPS-Tech rev 5.3

62

Let´s recall what we have seen...

• 4 Quadrant inverter can operate in either forward (inverter mode) or reverse (rectifier mode)

• It can operate with constant voltage or constant current control.

• The voltage/current is kept to the reference • There is a regulation, where the actual value is compared to the reference. The result is given to the controller, which is adjusting the value.

Two inverters - Is that all in a UPS?Two inverters - Is that all in a UPS?Not all - Lets see the other componentsNot all - Lets see the other components

Delta-ConversionDelta-ConversionAnything more…?Anything more…?

Main components

UPS-Tech rev 5.3

63

Static Switch

• The Static switch consist of anti-parallel connected thyristors.

• There are two static switches one for mains and one for bypass.

Purpose of the Static switch

• Bypass static switch is to ensure uninterrupted transfer to mains supply in case of overload or inverter failure.

• Main static switch ensures that the UPS will not feed back into mains, during battery operation upon mains failure.

Delta-ConversionDelta-ConversionStatic SwitchStatic Switch

Main components

Static Switch

UPS-Tech rev 5.3

64

Main Static Switch

• The Static switch consist of anti-parallel connected thyristors • Each thyristor is controlled separately • This is possible due to the unity Power factor • This ensure that the UPS will not feed back into a mains short circuit

12

Mains short circuit in period 1

Thyristor 2 will be off and cannot carry current towards the short circuit.

Thyristor 1 is conducting the current into the UPS, but the thyristor cannot conduct current in the opposite direction - it works as a diode.

Delta-ConversionDelta-ConversionMain Main Static SwitchStatic Switch

Main components

1

2

UPS-Tech rev 5.3

65

Bypass Static Switch

• The Static switch consist of anti-parallel connected thyristors

• The thyristor is controlled in pairs.

• In Bypass there is no regulation of the power factor so we need to energise both of them.

Delta-ConversionDelta-ConversionBypass Static SwitchBypass Static Switch

1

2

Main components

1

2

Due to the overlapping voltage and current we have to energise the

thyristors in pairs

UPS-Tech rev 5.3

66

The final components...

Back feed protection contactor...

• Have same purpose as the Main static switch, but has a physical separation.

• Filters on in and output

• Used to suppress the harmonic content of the voltage and currents in the unit, caused by the load and the switching of the inverter.

Delta-ConversionDelta-ConversionThe final components The final components

Main components

That´s all - Now lets build the UPS circuit

diagram...

UPS-Tech rev 5.3

67

HeadHead lineslines

Delta-Conversion Delta-Conversion circuit diagramcircuit diagram

Power interruptions

What is a UPS ?



Load-step pictures

Power flow



Questions...

UPS-Tech rev 5.3

68

The Main Inverter...

Main Inverter

PWM

Output voltage ref.

Delta-ConversionDelta-ConversionThe circuit diagram - main inverter The circuit diagram - main inverter

Main inverter

Circuit diagram

UPS-Tech rev 5.3

69

Now we add the Delta inverter...

Output

L

N

Delta Inverter Main InverterBattery

PWM PWM

Output voltage ref.Battery voltage ref.

Input current ref.

Circuit diagram

Delta-ConversionDelta-ConversionThe circuit diagram - main inverter + Delta inverterThe circuit diagram - main inverter + Delta inverter

UPS-Tech rev 5.3

70

Total system...

Delta Inverter Main InverterBattery

PWM PWM

Bypass SSW

Mains SSW

Mains Input

N

L

Sync.

Crystalcontr.

Output voltage ref.Battery voltage ref.

Input current ref.

Delta-ConversionDelta-ConversionThe circuit diagram - the total system The circuit diagram - the total system

Circuit diagram

UPS-Tech rev 5.3

71

We have now build up the system...

Please answer the following questions:

• What is the working principle of the Main inverter ?

• What is the working principle of the Delta inverter ?

• What is the purpose of static switches ?

• What function does the Main inverter have ?

• What function does the Delta inverter have ?

Brush up !

Delta-Conversion - Delta-Conversion - Questions...Questions...

Circuit diagram

How are the

Batteries

charged ?

UPS-Tech rev 5.3

72

The batteries are charged by passing energy through the fly-back diodes of the inverter - it´s a kind of work-sharing between the inverters

• The Delta inverter monitors the voltage of the batteries and in case of need for more energy, the control gains the current reference for the input current.

This results in an increasing input Power

• As the output does not demands more Power, the energy will due to Kirchoff law flow to the battery as the energy have to be in balance.

Battery Charging

Input power 110% output power 100%

Battery Power 10%We cannot store energy in a point

Delta-ConversionDelta-ConversionBattery ChargingBattery Charging

Circuit diagram

UPS-Tech rev 5.3

73

Questions...

Conclusion and...Conclusion and...


What is a UPS ?



Load-step pictures

Power flow



Questions...

UPS-Tech rev 5.3 1 Show information... Navigation links: Move the cursor across the links and wait for the “hand” symbol - then click left mouse key. Click.

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