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UPS-Tech rev 5.3

2. UPS Technology & Delta-Conversion
UPS-Tech rev 5.3

3. Option: Select and jump
UPS Technology index...
Option: Select and jump
to a specific subject...
Head lines
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. Head lines Power interruptions 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

5. Power Quality - Distribution
Power interruptions
“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
……..
UPS-Tech rev 5.3
Liberalization of the power market - will result in decreasing power quality

6. Power quality is also influenced by...
Power interruptions
UPS
Power
disturbances
Motors
Few of many disturbances...
UPS-Tech rev 5.3

7. Poor power quality... - on power critical applications... means…
Power interruptions
- on power critical applications...
means…
System Downtime
Black screen
System Lock up
Lost or corrupted data
Keyboard lock-up
Hardware corruption
UPS-Tech rev 5.3

8. Power interruptions Power break down Low voltage High voltage
UPS-Tech rev 5.3

9. Power interruptions Spikes Harmonics Combined interruptions
UPS-Tech rev 5.3

10. Constant Clean Power “The perfect wave”
Power interruptions
- the optimal power condition...
Constant
Clean
Power
more solutions
available…
few
“close to perfect”
UPS-Tech rev 5.3

11. Head lines What is a UPS 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...
What is a UPS
UPS-Tech rev 5.3

12. UPS … means Un-interruptible Power Supply
What is a UPS ?
What is a UPS ?
200V V
230V +/-1%
A UPS ensures...
Up-time
Data Safety
Hardware protection
UPS … means Un-interruptible Power Supply
UPS-Tech rev 5.3

13. Requirements to your UPS...
What is a UPS ?
Low heat dissipation
Low audible noise
Lowest installation cost
No electrical disturbances
Resistive load - PF1
UPS
Constant clean power
Lowest electricity bill
Low weight
Small foot print
UPS-Tech rev 5.3

14. Consider your UPS requirements
What is a UPS ?
Low heat dissipation
Low audible noise
Efficiency
Cooling requirement
more solutions
available…
few
“close to perfect”
Lowest installation cost
No electrical disturbances
Resistive load - PF1
UPS
Constant clean power
Lowest electricity bill
Size of cable and fuses ?
Mains repercussion - EMC ?
Phase compensation ?
The technology
Efficiency
Service organization
Supplier reputation
Low weight
Small foot print
The technology
Efficiency and cabinet
UPS-Tech rev 5.3

15. UPS Installation What is a UPS ? Input Panel Diesel Generator
Mains Supply
SBP
Distribution Panel
Loads
UPS
UPS-Tech rev 5.3

16. UPS technologies... Standby system Line interactive Double conversion
What is a UPS ?
Standby system
Line interactive
Double conversion
UPS-Tech rev 5.3

17. UPS technologies... Rotary conversion Single conversion 2nd
What is a UPS ? M G
Rotary conversion
Single conversion 2nd
Delta-Conversion
Single conversion 1st
UPS-Tech rev 5.3

18. The different types of UPS systems
Head lines
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...
The different types of UPS systems
UPS-Tech rev 5.3

19. UPS systems of today is more than...
On-line (working)
Off-line (sleeping)
“Standby”
Introduction…
Background:
It is widely believed that there are only two types of UPS systems, namely standby type UPS and online type of UPS These two terms are, as commonly understood, not correctly applied to many UPS systems on the market today.
Many misunderstandings about UPS systems are cleared up when the different types of UPS topologies are properly identified.
The commonly used terms “On-Line” and “standby” do not correctly describe the majority of UPS systems available.
This note describes the most common UPS types available today and attempts to explain their fundamental differences.
It is shown that different UPS types are appropriate for different applications, and that there is no single UPS type that is ideal for all applications.
There are significant differences in UPS design between available products on the market, with the theoretical and practical advantages for different approaches.
Nevertheless, the basic quality of design implementation and manufactured quality are often dominant in determining the ultimate performance achieved in the customer application. *
UPS-Tech rev 5.3

20. Different UPS topologies...
UPS systems
Standby
Line Interactive
Standby On-Line Hybrid
Standby Ferro
Double Conversion On-Line
Delta Conversion On-Line
...most common
Tech Note #T1
Title: Tech note T1 v2
Author: Neil Rasmussen/CORP NAM/ APCC
Data:
This Technical note explains the different types of UPS and there characteristics by block diagrams.
Identifying the topologies - is to understand the differences *
UPS-Tech rev 5.3

21. The Standby UPS... * Benefits: Limitations: UPS systems 0 - 0.5 kVA
Surge
Suppressor
Filter
Battery + -
Inverter
D C
A C
Charger
AC/DC
Load
Transfer
Switch
kVA
The Standby UPS…
The Standby UPS is the most common UPS Type used for Personal Computers.
In The block diagram below, the transfer switch is set to choose the filtered AC input as the primary power source (solid line path), and switches to the battery/inverter as the backup source in case of the failure of the primary source(AC).
In case of power failure, the transfer switch must operate to switch over to the battery/inverter backup power source (gray path).
The inverter only starts when the power fails, hence the name “Standby”.
Benefits:
Limitations:
High efficiency
Compact
Low cost
Uses battery during brownouts
Impractical over 2kVA *
UPS-Tech rev 5.3

22. The line Interactive UPS...
UPS systems
Battery + -
Transfer
Switch
Inverter
D C
A C
Load
Charging (normal)
Discharging (Power fail)
kVA
The Line Interactive UPS…
The line interactive UPS is the most common UPS, used for small business, Web, and departmental servers. In this design, the battery-to-ac power converter (inverter) is always connected to the output of the UPS.
Battery charging is provided by operating the inverter in reverse during times when the input AC power is normal. When the input power fails the transfer switch opens and the power flow is from battery to the UPS output. The fact that the inverter is always connected to the output provides additional filtering, and yields reduced switching transients when compared with the standby type UPS.
The inverter also provides regulation, operating to correct brownout conditions which would otherwise force the UPS to switch to battery operation. This allows the UPS to operate at sites with very poor power. The inverter can be designed such that it´s failure will still permit power flow from the AC input to the output, which eliminates the potential of single point failure and effectively provides for two independent power paths.
This topology is inherently very efficient which leads to high reliability while at the same time providing superior power protection. High efficiency, low cost, high reliability coupled with the ability to correct low or high line voltage conditions make this the dominant type of UPS in the 0.5-5kVA power range.
Benefits:
Limitations:
High reliability
High efficiency
Good voltage conditioning
Impractical over 5 kVA *
UPS-Tech rev 5.3

23. Standby On-line Hybrid...
UPS systems
Rectifier
Combiner
Load
Inverter
D C
A C
Battery
Charger
AC/DC
Standby
DC to DC
Converter + -
Standby On-Line Hybrid…
The Standby On-Line Hybrid is the topology used for most UPS under 10kVA which are labeled “on-line”.
The standby converter from the battery is switched on when an AC power failure is detected, just like in a standby UPS. The battery charger is small, just like in a standby type UPS. This UPS will exhibit no transfer time during an AC power failure.
The most misunderstood part about this topology is the belief that the primary power path is always “on-line” when in fact, the power path from the battery to the output is only half “on-line” (the inverter), while the other half (the dc-dc converter) is operated in the standby mode. This design is sometimes fitted with an additional transfer switch for bypass during a malfunction or overload.
kVA
Benefits:
Limitations:
Excellent voltage conditioning
Low efficiency
Low reliability
High cost
Impractical over 5kVA *
UPS-Tech rev 5.3

24. The Standby-Ferro UPS…
UPS systems
Battery + -
Inverter
D C
A C
Charger
AC/DC
Load
Transfer
Switch
Transformer
kVA
The Standby-Ferro UPS…
The Standby-Ferro UPS was once the dominant form of UPS in the 3-15kVA range. This design depends on a special transformer that has three windings (power connections). The primary power path is from AC input, through a transfer switch, through the transformer, and to the output. In the case of a power failure the transfer switch is opened, and the inverter picks up the output load.
In the Standby-Ferro design, the inverter is in the standby mode, and is energized when the input power fails and the transfer switch is opened. The transformer has a special “Ferro-resonant” capability which provides limited regulation and output waveform “shaping”.
The isolation from AC power transients provided by the Ferro transformer is as good or better than any filter available, but the Ferro transformer itself creates severe output voltage distortion and transients which can be worse than a poor AC connection (see APC Technical Note T12).
Even though it is inherently a standby UPS, the Standby-Ferro generates a great deal of heat because the Ferro-resonant transformer is inherently inefficient. The best known example of this type of UPS is the BEST Ferrous. Standby-Ferro UPS systems are frequently represented as On-Line units even though they have a transfer switch, the inverter operates in the standby mode, and they exhibit a transfer characteristic during an AC power failure.
High reliability and excellent line filtering are the strengths of the Standby-Ferro design. However, the design has very low efficiency combined with instability when used with some generators and never power-factor corrected computers. This has caused the popularity of this design to decrease significantly.
Benefits:
Limitations:
Excellent voltage conditioning
Low efficiency
Unstable in combination with some
loads and generators *
UPS-Tech rev 5.3

25. The Double Conversion On-Line UPS...
Surge
Suppressor
Filter
Battery + -
Inverter
D C
A C
Charger
AC/DC
Load
kVA
UPS systems
The Double Conversion On-Line UPS…
This is the most common type of UPS above 10kVA.
The block diagram of the Double Conversion On.Line UPS is the same as the Standby UPS except that the primary power path is the inverter instead of the AC mains.
In the design of Double Conversion On-Line operation, failure of the input AC does not cause activation of the transfer switch, because the input AC is NOT the primary source, but is rather the backup source. Therefore, during an input AC power failure, on line operation results in no transfer time.
The on line mode of operation exhibits a transfer time when the power from the primary battery charger/ battery/ inverter power path fails. This can occur when any of the blocks in this power path fail. The inverter power can also drop out briefly, causing a transfer, if the inverter is subjected to sudden changes in load, or if the inverter experiences an internal control “glitch”.
Contrary to popular belief, Double Conversion On-Line UPS systems do exhibit a transfer time, and in actual installations may transfer as frequently as standby type UPS systems; however on line UPS transfers are not related to AC input power failures as they are in a standby UPS.
Both battery charger and the inverter convert the entire load power flow in this design, which causes undesirable heat results in reduced efficiency.
Due to practical design constraints, UPS below 10kVA which are represented as Double Conversion On-Line UPS are almost always actually of the Standby On-Line Hybrid type described previously.
The Double Conversion On-Line UPS provides nearly ideal electrical output performance. However, the constant wear on the power components reduces reliability over other designs and the energy consumed by the electrical power inefficiency is a significant part of the lift-cycle cost of the UPS. Also, the input power drawn by the large battery charger is often non-linear and can interfere with building power wring.
Low efficiency
Impractical under 5kVA
Excellent voltage conditioning
Ease of paralleling
Benefits:
Limitations: *
UPS-Tech rev 5.3

26. The Delta Conversion On-Line UPS...
Surge
Suppressor
Inverter
D C
A C
Load
Battery + -
kVA
Delta
Converter
Filter
UPS systems
The Delta Conversion On-Line UPS…
This UPS design is a new technology that was recently introduced to eliminate the drawbacks of the Double Conversion On-Line design and is available from 5kVA and greater.
Like the Double Conversion On-Line design, the Delta Conversion On-Line UPS always has the inverter supplying the load voltage. However, the additional Delta Converter also contributes power to the inverter output.
Under conditions of AC failure or disturbances, this design behaves identically to the Double Conversion On-Line.
Benefits:
Limitations:
High efficiency
Excellent voltage conditioning
Ease of paralleling
Compact
Impractical under 5kVA *
UPS-Tech rev 5.3

27. Comparing UPS characteristics ...
UPS systems
Practical
power range
(kVA)
Voltage conditioning
Cost per VA
Efficiency
Inverter always operating
Char.
Technique
Standby
Low
Low
Very High No
Line interactive
Design depending
Medium
Very High
Design depending
Standby On-Line Hybrid
High
High
Low
Partially
Standby Ferro
3 - 15
High
High
Low No
Double Conversion On-Line
Summary of UPS types…
The following is a summery table showing some of the characteristics of the various UPS types.
Some attributes of a UPS, like efficiency, are dictated by choice of UPS type. However, many of the attributes of a UPS, like reliability, are much more strongly affected by the implementation and the manufactured quality than by the design type. Therefore, this summary is necessarily incomplete.
High
Medium
Low
Yes
Delta Conversion On-Line
High
Medium
High
Yes
The unique combination... *
UPS-Tech rev 5.3

28. Comparing UPS characteristics ...
APC´s Findings
Char.
Technique
Limitations
Benefits
Used in APC products
Best value for personal workstations
Uses battery during brownouts
Impractical over 2kVA
Low cost
High efficiency
Compact
Back-UPS
Standby
High reliability
Ideal for rack or distributed servers
For and harsh power environment
Impractical over 5kVA
Good voltage conditioning
Smart UPS
Line interactive
Good reliability
Low efficiency
Low reliability
High cost
Excellent voltage conditioning
Not used by APC
Standby On-Line Hybrid
Limited application due to low efficiency
Instability problems
N+1 On-Line design offers better reliability
Unstable in combination with some loads and generators
Standby Ferro
Well suited for N+1 designs
Impractical under 5kVA
Ease of paralleling
Symmetra
Double Conversion On-Line
Delta Conversion On-Line
Outstanding Return Of Investment benefit, at high power plant
DP300E
Use of UPS types by APC…
The APC product offering has evolved over time to use many of the various UPS types.The different UPS types have attributes that make them more or less suitable for different applications and the APC product line reflects this diversity as shown in the table below: *
UPS-Tech rev 5.3

29. Delta-Conversion tech. and performances
Head lines
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...
Delta-Conversion tech. and performances
UPS-Tech rev 5.3

30. On-line Delta-Conversion “Close to perfect” solution
UPS-technologies
On-line Delta-Conversion
“Close to perfect” solution
Delta-Converter
Battery
Load
Mains
...is
Combining advantages
from
existing
technologies
On line technology
Pure sinusoidal output power
Maximum protection against spikes, surges, sags and power break down
Clean output at all time
Optimum system efficiency
Full rated output available in kW
Input power factor corrected to 1
No mains repercussions
Small footprint
200% overload capability
Energy losses < 4%
UPS-Tech rev 5.3

31. Delta-Conversion On-Line and high efficiency…?
UPS-technologies
what´s the trick…?
UPS-Tech rev 5.3

32. The Energy Saving Trick...
UPS-technologies
Double conversion
4. Floor
5. Floor
Delta Conversion
Understanding the Delta Conversion principle...
A simple way to understand why this works is to consider the energy required to deliver a package from the 4. floor to the 5. floor of a building as shown in the diagram.
It obviously saves energy to carry the package only the difference (delta) between the starting and ending points.
The Double Converter moves much of the power from input to the output directly.
In the Delta Conversion On-Line design the Delta Converter can also charge the battery so the overall design is not more complex than the Double Conversion approach.
The Delta Conversion On-Line UPS provides the same output characteristics as the Double Conversion On-Line design. In addition, the Delta Conversion On-Line UPS offers reduction en energy losses and costs by approximately a factor of 4. As a side-effect of the design, the input power quality of the Delta Conversion UPS is also superior, particularly in the large kVA sizes.
Delta Conversion On-Line technology is the only core UPS technology today protected by patents and it is therefore not likely to be available from a broad range of UPS suppliers for some time.
UPS-Tech rev 5.3

33. Who makes the trick...
UPS-technologies
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-Tech rev 5.3

34. Regulating the delta, ± diff. in/out
Silcon DP300E - power flow
UPS-technologies
Mains
input
Regulating the delta, ± diff. in/out
Delta
Inverter
1. Normal operation
2. Regulated operation
Main
Inverter
Load
3. Battery operation
Battery
4 Recharge battery
UPS-Tech rev 5.3

35. Diesels Best Friend... 100 kW 130 kVA 100 kVA 300 - 500 kVA
UPS-technologies
100 kW
DIESEL
Silcon DP300E
130 kVA
No harmonics
Almost same size as UPS
100 kVA
Legacy
UPS
kVA
Harmonics
3-5 times oversized
UPS-Tech rev 5.3

36. Diesel / DP300E installation
Diesels Best Friend...
UPS-technologies
Diesel / DP300E installation
Mains Supply
Input Panel
SBP
Distr. Panel
DP310E - DP340E
Loads
Diesel Generator
UPS-Tech rev 5.3

37. Diesel Generator Delta-conversion 1 2 1 2 UPS-technologies
and single-conversion
Smaller diesel generator
can be used due to:
Power factor corrected
regardless of load
Soft start – no load step
for the generator
UPS:
DP3480E with 480
kW load
Diesel Generator:
625kVA/500kW
CH1
CH2
CH3
CH4
CH1
CH2 1 2
CH 1: Input Voltage
CH 2: Input Current
CH 3: Output Voltage
CH 4: Output Current
(100% SMPS load)
CH 1: Input Current
(0-100%) during soft start
CH 2: Frequency
variations on diesel
generator during soft start.
UPS-Tech rev 5.3

38. Two way filter Delta-conversion 1. The load is protected
UPS-technologies
Delta-conversion
& single-conversion
1. The load is protected
against mains side
harmonics
2. Harmonics from unlinear
(SMPS) load are filtered
out (not fed back to the
mains)
CH1
CH2
CH1
CH2
CH3
CH4
CH 1: Input Voltage
CH 2: Output Voltage
CH 1: Input Voltage
CH 2: Input Current
CH 3: Output Voltage
CH 4: Output Current
(100% SMPS load)
UPS-Tech rev 5.3

39. UPS comparative analysis...
UPS-technologies 1
Double conversion UPS 2
Typical 30% input current distortion 1 2
Single conversion UPS 1
Delta-conversion UPS 2
No input current distortion
Complies to G 5/3 and future norms
1 = Input voltage
2 = Input current
UPS-Tech rev 5.3

40. Silcon DP300E: 10 - 480 kVA 3-phase
UPS-technologies
Built-in Batteries
External
Batteries
External Batteries
UPS-Tech rev 5.3

41. Comparative conclusion
UPS-technologies
True no-break protection
Yes
Capability of running SMPS load
without derating
True 2-way filter function
Sinusoidal input current No
> 30% distortion
Optional
Unity input power factor
but expensive
Optional.
Energy losses, large systems
> 10 kVA <100 kVA
> %
< 5%
< 4%
> 100 kVA
> %
Energy losses, small systems
< 10 kVA
> %
< 8%
Basic properties
Double conversion
UPS
Single conversion UPS
Delta conversion UPS
Comparative chart
UPS-Tech rev 5.3

42. DP300E - load step pictures
Head lines
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...
DP300E - load step pictures
UPS-Tech rev 5.3

43. DP300E - Load Step 100% load step 0% 1 Load step pictures
Input voltage
Output voltage
Input current
Output current
100%
load step 0%
UPS-Tech rev 5.3

44. DP300E - Load Step load step 100% 0% 2 Load step pictures
Input voltage
Output voltage
Input current
Output current
load step 100% 0%
UPS-Tech rev 5.3

45. Input terminals - short circuit
DP300E - Short Circuit 3
Load step pictures
Input voltage
Output voltage
Input current
Output current
Input terminals - short circuit
Normal operation to battery operation
UPS-Tech rev 5.3

46. Output terminals - short circuit
DP300E - Short Circuit 4
Load step pictures
Output voltage
Output current
Output terminals - short circuit
- fuse clearing in battery operation
UPS-Tech rev 5.3
CH 2: Output Voltage
CH 4: Output Current

47. Head lines Power Flow analysis... 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...
Power Flow analysis...
UPS-Tech rev 5.3

48. Power Flow analysis... nominal mains voltage
100%
100%
Current 100%
100%
100%
Power 100%
100%
100% 0% 0%
Mains
input
Delta
Inverter
Main
Inverter
Battery
UPS-Tech rev 5.3

49. Power Flow analysis... -15% mains voltage
Current 115%
Power 100%
100%
115%
15%
Mains
input
Battery
Delta
Inverter
Main
UPS-Tech rev 5.3

50. Power Flow analysis... + 15% mains voltage
Current 85%
Power 100%
100%
85%
15%
Mains
input
Battery
Delta
Inverter
Main
UPS-Tech rev 5.3

51. Power Flow analysis... battery charging
Voltage 100%
Current 110%
Power 110%
100%
110%
10% 0%
Mains
input
Battery
Delta
Inverter
Main
UPS-Tech rev 5.3

52. Delta-Conversion main components
Head lines
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...
Delta-Conversion main components
UPS-Tech rev 5.3

53. DP300E principle diagram Load Main inverter Delta inverter
Main components
Load
Main inverter
Delta inverter
UPS-Tech rev 5.3

54. Delta-Conversion Main inverter
Main components
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
UPS-Tech rev 5.3

55. Delta-Conversion Delta inverter
Main components
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
UPS-Tech rev 5.3

56. Delta-Conversion control loops
Main components
Delta-inverter
Load
Mains
input
Battery
Main inverter
V out sense
V 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.
UPS-Tech rev 5.3

57. Delta-Conversion Basic configuration:
Main components
Basic configuration:
4Q-PWM Inverter is capable of distribute energy
in either forward or reverse direction. Meaning that the
inverter can work as a charger as well.
In the UPS we use the fly-back diodes to pass energy to the
batteries.
Half-bridge 4Q-inverter
Iout
Vout 3.
Inverter 1. 2.
Charger 4.
4Q Pulse-Width Modulated Inverter
UPS-Tech rev 5.3

58. Delta-Conversion Forward mode/Inverter mode
Main components
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.
Half-bridge 4Q-inverter
Iout
Vout 3.
Inverter 1. 2.
Charger 4.
4Q Pulse-Width Modulated Inverter
UPS-Tech rev 5.3

59. Delta-Conversion Reverse mode/ rectifier mode
Main components
Iout
Vout 3.
Inverter 1. 2.
Charger 4.
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
UPS-Tech rev 5.3

60. Delta-Conversion Main Inverter
Main components
Main inverter
4 Q Pulse-Width Modulated Inverter
Main Inverter
PWM
Output voltage ref.
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.
UPS-Tech rev 5.3

61. Delta-Conversion Delta Inverter
Main components
Delta-inverter
4 Q Pulse-Width Modulated Inverter
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.
Delta Inverter
Battery
PWM
Battery voltage ref.
Input current ref.
UPS-Tech rev 5.3

62. Delta-Conversion Anything more…?
Main components
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?
Not all - Lets see the other components
UPS-Tech rev 5.3

63. Delta-Conversion Static Switch
Main components
Static Switch
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.
UPS-Tech rev 5.3

64. Delta-Conversion Main Static Switch
Main components
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
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. 1 2 1 2
UPS-Tech rev 5.3

65. Delta-Conversion Bypass Static Switch
Main components
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.
Due to the overlapping voltage and current we have to energise the thyristors in pairs 1 2 1 2
UPS-Tech rev 5.3

66. Delta-Conversion The final components
Main components
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.
That´s all - Now lets build the UPS circuit diagram...
UPS-Tech rev 5.3

67. Delta-Conversion circuit diagram
Head lines
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...
Delta-Conversion circuit diagram
UPS-Tech rev 5.3

68. Delta-Conversion The circuit diagram - main inverter
The Main Inverter...
Main inverter
UPS-Tech rev 5.3

69. Delta-Conversion The circuit diagram - main inverter + Delta inverter
Now we add the Delta inverter...
UPS-Tech rev 5.3

70. Delta-Conversion The circuit diagram - the total system
Delta Inverter
Main Inverter
Battery
PWM
Bypass SSW
Mains SSW
Mains Input N L
Sync.
Crystal
contr.
Output voltage ref.
Battery voltage ref.
Input current ref.
UPS-Tech rev 5.3

71. Delta-Conversion - Questions...
Brush up !
Circuit diagram
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 ?
How are the Batteries charged ?
UPS-Tech rev 5.3

72. Delta-Conversion Battery Charging
Circuit diagram
Battery Charging
Input power 110%
output power 100%
We cannot store energy in a point
Battery Power 10%
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.
UPS-Tech rev 5.3

73. Questions... Conclusion and... Head lines 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...
Questions...
UPS-Tech rev 5.3