Very High Power PEBB technology - VDE

Very High Power PEBB technology BRUECKNER Thomas 

Acknowledgements 

Very High Power PEBB technology 

P. K. Steimer, O. Apeldoorn, B. Ødegård 

ABB Switzerland Ltd. 

Power Electronics and MV drives 

5300 Turgi - Switzerland 

Tel.: +41 – 58 – 589 38 88 

Fax: +41 – 58 – 589 25 79 

E-Mail: peter.steimer@ch.abb.com 

URL: http://www.abb.com 

S. Bernet, T. Brückner 

Berlin University of Technology 

FG Power Electronics 

10587 Berlin - Germany 

Tel.: +49 30– 314 – 25855 

Fax: +49 30 – 314 – 25526 

E-Mail: steffen.bernet@tu-berlin.de 

URL: http://www.tu-berlin.de 

The authors gratefully acknowledge the contributions of Terry Ericson on the PEBB concept, which 

linked perfectly into the basic ideas of a platform-based approach to power electronics. The work 

presented was supported by ONR under the agreement N o . N00014-99-3-0002 “Very High Power PEBB 

Demonstration”. 

Keywords 

«High power discrete device», «IGBT», «IGCT», «Multilevel converters», «FACTS» 

Abstract 

In the field of power electronics the Power Electronics Building Block (PEBB) is a key functional 

component. With regard to the applications, it is of outmost importance that the PEBB technology used is 

compact, cost-effective and reliable. 

The IGCT is at the forefront of technology in high power, medium-voltage applications. For further 

improvement in size and costs a new ANPC IGCT PEBB has been developed. The main new technologies 

to achieve higher powers are the new low-inductive gate-unit to maintain hardswitched operation up to 

more than 6000A, the increased SOA of the 91mm asymmetric IGCT (4 inch technology) and the 

antiparallel diode up to more than 6000A and the Active NPC technology, which allows an optimum and 

equal loss balancing in all power semiconductors 

The maximum inverter output power has been increased by 80% with a parallel increase in the power 

density and reduced costs per kVA. 

EPE 2005 - Dresden ISBN : 90-75815-08-5 P.1


Introduction 

Power electronics is a technology of continuously growing importance in multiple areas like 

• power generation 

• transmission and distribution 

• multiple industrial applications and 

• transportation. 

Mature applications may be found in static excitation systems for power generation, HVDC 

transmission systems, rectifiers for DC loads, UPS products, adjustable speed drives and converters for 

rolling stock. Emerging applications for power electronics have been evolving in all the above areas, such 

as : 

• new voltage-source converter based HVDC transmission systems (HVDC light), 

• new FACTS solutions like the UPFC or SSSC for powerflow and STATCOM for voltage 

control, 

• new Custom Power products to protect critical loads, like dynamic voltage restorers (DVR), 

• new energy storage solutions based on flywheel technology, conventional and advanced 

batteries and 

• new distributed power generation solutions based on windturbines, microturbines and fuel cells. 

More and more PEBB based approaches to power electronics are chosen to exploit the synergies of 

multiple applications. In the field of power electronics the PEBB is a key functional component, which 

enables a platform-based approach. 

Definition of the Power Electronics Building Block (PEBB) 

The functionality of a PEBB [1], as a basic building block, can be defined as power conversion (single 

phase or multiple phases) including (Fig. 1) 

• power supply for gate drives and sensors 

• stack or module assembly including gate drives 

• voltage, current and temperature sensors incl. A/D conversion of sensor signals 

• switching control incl. pulse generation for gate drive 

• communication with control and 

• primary protection. 

The interfaces of a PEBB can be defined as follows: 

• auxiliary power interface 

• control interface 

• power interfaces and 

• cooling interface. 

With this proposed definition [2], the complexity of power electronics systems can be reduced due to 

basic building block and interface definition. The interface with the highest complexity is that between the 

PEBB and the control. This interface may also have a different definition and functionality depending on 

the degree of integration within the PEBB. 

To achieve a clearly defined, scalable and easy to implement interface between the control and the 

PEBB it is proposed that, in very high power applications, additional intelligence be included within the 

PEBB. This additional intelligence should be based, in a first step, on the level PEBB control (see Fig. 1), 

which includes the following functionality 

• modulator with switching logic and 



• the 2 nd level of protection. 

This additional intelligence should be physically located close to the power part of the PEBB as 

distributed intelligence. 

A / D & D/A 

V DC1 T 

V 

PLL, αβ ↔ dq Transformations 

id / iq current control 

2nd 2 level 

protection 

nd level 

protection 

System control 

Application control 

Gate drives & 

device protection 

FB 

Modulator 

Converter 

switching logic 

6 

1..6 

A / D & D/A 

I A/B/C V A/B/C 

(optional) 

V 

Configuration 

& & diagnostics diagnostics 

Application Control 

- overriding control & measurements 

Converter Control 

- PLL synchronization 

- αβ ↔ dq Transformations 

- id- and iq current control 

PEBB Control 

- Modulator 

- Converter switching logic 

- 2nd - Modulator 

- Converter switching logic 

- 2 level protection 

nd level protection 

PEBB 

- Stack or module assembly 

- Snubbers for safe commutation 

- Gate drives & feedbacks 

- 1st - Stack or module assembly 

- Snubbers for safe commutation 

- Gate drives & feedbacks 

- 1 level device protection 

- A/D & D/A conversion 

- Gate drive power supply 

- Current and voltage sensors 

- AC/DC power terminals 

- Thermal management 

st level device protection 

- A/D & D/A conversion 

- Gate drive power supply 

- Current and voltage sensors 

- AC/DC power terminals 

- Thermal management 

Fig. 1: PEBB and its possible levels of integration according to IEEE guide [3] 

1ms..1s.. 

10 µs..1ms 

1..10 µs 

0.1..1 µs 

In a next step it is possible to include within the PEBB the next level, i.e. the Converter Control. This 

may happen first at lower powers. In such a solution the following additional functionalities would be 

integrated within the PEBB: 

• synchronization with the connected AC system 

• transformation of the variables in to rotating systems 

• current control within the rotating systems. 

It is important to understand that the definition of a PEBB allows a high level of flexibility and that 

PEBB definitions exist with highly different levels of integration. But in all cases the interfaces of the 

PEBB and its own functionality are clearly defined. 

PEBB Type 1 = PEBB Powerpart 

PEBB Type 2 = PEBB Powerpart + 

PEBB Control 

PEBB Type 3 = PEBB Powerpart + 

PEBB Control + 

Converter Control 

PEBB Type 4 = …. 

As mentioned before, for very high power applications, it is proposed to use the PEBB Type 2, i.e. the 

PEBB Powerpart with integrated PEBB Control functionality. 



Power Semiconductor Technology 

Silicon based power semiconductors are an essential key component of the PEBB. It is therefore 

important, that the basic properties of the commonly used power semiconductors are understood. 

The low-voltage IGBT module 

The low-voltage IGBT module is used in low-voltage applications up to few megawatts with system 

voltages in the range of 240V up to 690V. With its typical dynamic blocking voltage in the range of 600V 

up to 1700V it is the dominant power semiconductor in these applications. The typical PWM carrier 

frequencies in the higher power range are in the range of a few kHz, typically 3 – 5 kHz. The dominant 

applications of the low-voltage IGBT module are low-voltage AC drives, where these power 

semiconductors are used in high volumes. 

Econopack /SKiiP/LoPak Module 1200 V und 1700 V 

Maximum blocking voltage 

Fig. 2: The low-voltage IGBT module 

The medium-voltage-IGBT module 

IHV / HiPak Module (E1/E2) 

Turn off 3x rating current (3300V IGBT) 

75 – 450 A 

Maximum phase current 

Switching frequency (f PWM) 

1200 V: Typical 3..5 kHz 

Integration 

Fig. 3: The medium-voltage IGBT module 

Electrical insulation 

Up to six switching devices 

Loss-optimized 

Soft Punch Through or 

Trench 

Copper base plate (EconoPack) 

Limited in thermal cycles 

2500 V, 3300 V and 6500 V 


1500 A, 1200 A, 600 A 


Switching frequency (f PWM ) 

3300 V: Typical 1..2 kHz 

Integration 

Electrical insulation 

Up to 2 devices (dual pack) 



Trench 

AlSiC base plate 

Traction 

The medium-voltage IGBT module with dynamic blocking voltages in the range of 2500 V to 6500V is 

used in medium-voltage applications up to a few megawatts. The typical PWM carrier frequencies in these 

high power applications are in the range of 1 to 2 kHz. The dominant application for this power 

semiconductor is traction propulsion. 



The medium-voltage-IGCT Presspack 

The medium-voltage IGCT [4] is a presspack device with its typical dynamic blocking voltage in the 

range of 4500V to 6000V. It consists of one bipolar wafer only, which has structures like a GTO device. It 

can therefore be manufactured on more simple wafer fabs, which already achieve low production costs 

with lower production volumes owing to the substantially lower investment costs. Additionally the one 

wafer solution needs inherently less edge termination area, than comparable solutions based on multiple 

small wafers. The IGCT is used in medium-voltage applications up to 100 MW and higher. The typical 

PWM carrier frequencies in high power applications are in the range of as low as 50 Hz up to 1 kHz. The 

dominant application of the medium voltage IGCT are medium-voltage AC drives, where these power 

semiconductors are used in high volumes. 

Today, the IGCT is the power semiconductor, which is best established in all high power applications. 

It has the most impressive reference list and is employed in the highest number of installations. 

As a thyristor-based power semiconductor, the IGCT has very low on-state losses. Owing to its 

integrated gate drive the turn-off occurs in an inherently robust transistor mode. Additionally, the 

presspack housing has the necessary attribute, that it fails short and any plasma is contained within the 

power semiconductor housing. This feature allows the implementation of robust and reliable protection 

concepts, which are essential for very high power applications. 

4 

3 

2 

1 

0 

-10 

-20 

V g 

(V) 

IGCT Presspack 

V d 

(kV) 

I Itg tg 

q 

V dm 

anode current I a 

thyristor x 

transistor 

starts to block 

anode voltage V d 

gate voltage 

V g 

I a (kA) 

1.5 2.0 2.5 3.0 3.5 t (µ s) 

4 

1 

3 

2 

0 

4500 V and 6000 V 


150 – 2000 A 



Typical 0.5 – 1 kHz 

Integration 

Gate unit 


Transparent Anode 

Thyristor-based 

Presspack 

Short circuit 

di/dt – snubber 

Fig. 4.: The medium-voltage IGCT presspack 

The medium-voltage IGBT Presspack 

The medium-voltage IGBT presspack with a typical dynamic blocking voltage of 2500V up to 4500V is 

used mainly in high voltage DC transmission up to a few 100 MW. The typical PWM carrier frequencies 

are in the range of 0.5 – 2 kHz. The IGBT presspack consists of multiple IGBT wafers, each needing its 

own small presspack structure. The IGBT chips are manufactured on the newest generation of IGBT wafer 

fabs, which are able to process the much finer structure required for this type of power semiconductor. 

When considering a power semiconductor switching at elevated frequencies, i.e. above 3 to 5 times 

the fundamental frequency, the IGBT has the advantage that the gate drive needs a smaller power supply. 

This is particularly beneficial in higher voltage applications, as the energy extraction on potential is 

simpler. This is one of the main reasons, that the IGBT presspack technology has been introduced in high 

voltage DC transmission systems, i.e. HVDC light based on voltage source converter technology. 



IGBT Presspack 

2500 V and 4500 V 


600 – 2000 A 



2500 V: typical 1 – 2 kHz 

4500 V: typical 0.5 – 1 kHz 

Integration 

Single device 



Trench 

Presspack 

Fig. 5.: The medium-voltage IGBT presspack 

Comparison of power semiconductors 

Short circuit 

In Fig. 6 a comparison of the features of the most important power semiconductors and their applications 

is made: 

• in the lower MW range the low-voltage IGBT module is the dominant design, combining low 

costs and high efficiency. 

• in the higher MW range, MV technology is used and the medium-voltage IGCT presspack is the 

dominant design up to several 100 MW owing to the benefits it provides with regard to : 

o Lower cabling efforts due to lower currents 

o Lower complexity due to lower parts count 

o Higher efficiency as the IGCT is derived from the lowest loss thyristor technology 

o Achieving a robust and reliable protection concept due to the presspack technology. 

• In high voltage DC transmission systems based on voltage source technology (HVDC light) the 

medium-voltage IGBT presspack technology, adapted to fulfill very specific HVDC 

requirements, has found its market niche. 

Application 

Cost 

IGBT Module 

Low- and 

medium-voltage 

Low 

IGCT Presspack 

Medium voltage 

(up to 15 kV) 

Power 1 – 5 MW 

5 – 100 MW 

Losses Medium 

Low 

Low 

IGBT Presspack 

Medium and HV 

(up to +/- 150kV) 

Scalability 

Parallel & Series 

Parallel 

Parallel & Series 

(with snubber) 

Type of failure Open (Plasma) Short circuit 

50 – 300 MW 

Medium 

Medium 

Short circuit 

LV Drives MV Drives HVDC light 

Traction FACTS FACTS 

Power Quality Power Quality 

Fig. 6: Comparison of the most important power semiconductors and their applications 

With regard to the applications, it is of the outmost importance that the PEBB technology used is 

compact, cost-effective, reliable and highly efficient. When focusing on the higher MW range up to more 

100 MVA the medium-voltage IGCT presspack technology is the prime choice, as it offers the lowest 

costs and the highest efficiency. Regarding series and parallel connection, the trade-offs are minor as only 

small snubbers, if any, are needed to overcome these limitations. 



NPC IGCT PEBB Technology 

The NPC IGCT PEBB 

Based on the highly competitive IGCT technology a very compact NPC IGCT PEBB, called PowerStack 

(Fig. 7.), serving multiple medium-voltage applications has been introduced to the market and the first 

commercial installations were commissioned in the year 2000. 

Fig. 7: NPC IGCT PEBB – a leading edge PEBB based on medium-voltage IGCT presspack technology 

Cd1 

Cd2 

Ls1 

Rcl1 

Rcl2 

Ls2 

Ccl1 

Ccl2 

NPC IGCT PEBB 

Dcl1 

Dcl2 

D5 

D6 

Fig 8: NPC IGCT PEBB Topology 

S1 

S2 

S3 

S4 

D1 

D2 

D3 

D4 

The maximum output power of the water-cooled NPC IGCT PEBB in a 3-phase configuration is in the 

range of 9 MVA. The NPC IGCT PEBB is a highly compact, highly reliable and efficient medium-voltage 

design, which defines the basic metrics for any competitive solution in this field. The system voltage with 

the 4500 V or 6000 V IGCTs is limited to 3300 V or 4160V correspondingly. 

Applications of the NPC IGCT PEBB) 

The NPC IGCT PEBB has been successfully introduced into the market to serve multiple, highly 

demanding, mature and emerging applications like 

• 9 – 27 MVA medium-voltage drives for various applications including rolling mills and marine 

propulsion, 

• 15 MVA back-to-back inter-tie to connect the 50 Hz grid and the 162/3Hz grid of European 

traction systems, 

• 15 – 60 MVA energy storage systems based on regenerative fuel cell technology or NiCd 



battery technology to enhance grid stability or to reduce power fluctuations. 

• 22 MVA Dynamic Voltage Restorers to safeguard the highly critical processes of a 

semiconductor plant. 

Fig. 9: Back-to-back intertie based on the NPC IGCT PEBB 

The New ANPC IGCT PEBB 

Limitations of the NPC IGCT PEBB 

The maximum output power of the NPC IGCT PEBB is limited mainly by two factors, i.e. 

• the safe operation area of the IGCT and 

• the thermal management of the power semicon-ductors. 

The maximum power of the conventional NPC IGCT PEBB is limited by the maximum turn-off 

capability of the IGCT and the corresponding companion diode. The maximum turn-off capability linked 

to the 4 inch wafer technology is in the range of 4000A at a DC voltage of 2800 Vdc. 

At the same time, in a conventional NPC converter with diodes clamped to the neutral point, the loading 

of the outer and the inner IGCT and corresponding antiparallel diodes is different, for example, at 

• a power factor equal to one 

• a high modulation and 

• delivering active power from DC to AC 

the outer IGCTs (S1, S4) of the NPC IGCT PEBB have reached their thermal limit, i.e. the thermal 

resistance of the IGCT and the water cooling circuit will not allow any higher losses. On the other side the 

inner IGCTs (S2, S3) are thermally loaded much less, as their losses are caused by conduction losses only. 

In case of inverse energy direction the same happens with the corresponding antiparallel diodes. 

The new technologies introduced with the ANPC IGCT PEBB 

To further improve the power density and the cost competitiveness of the leading IGCT PEBB technology 

the ANPC IGCT PEBB has been developed, which is able to deliver up to 16 MVA output power. The 

main new technologies introduced to achieve higher output powers are: 

• increased SOA of the 91mm asymmetric IGCT (4 inch technology) and of the antiparallel diode 

up to more than 6000A [5] and 

• improved thermal management by means of the Active NPC topology [6]. 



The low-inductive gate unit 

To keep the IGCT in the hard-switched mode during turn-off, the gate current rise time needs to meet the 

following requirements. Typically the maximum turn-off current needs to be achieved in less than 1us, 

with a gate unit voltage of approximately –20V. By utilizing newest technologies of FET and capacitors in 

the turn-off channel combined with an optimum PCB layout, values of more than 7-8 kA / µs can be 

achieved with the result that currents of up to 6000A and more can be turned-off safely. Higher values 

maybe possible, but the limit of the homogenous IGCT turn-off and the GTO type turn-off, with the risk 

of hot spots, needs to be carefully addressed. 

Fig. 10: Low-inductive 6000A IGCT gate unit 

New IGCT with increased SOA 

To achieve the needed higher turn-off current the IGCT technology has been further developed [5]. The 

development focused on 

• local improvement of the SOA, focusing on the IGCT cell level by optimizing the doping profiles 

and the irradiation. Record turn-off capabilities of 1 MW/ cm 2 have been achieved and 

• the reduction of lateral effects by optimizing the current distribution over the whole wafer area. 

Fig 11: 6.5 kA turn-off versus 2.8kVdc at 125°C with a 91mm asymmetric IGCT (4 inch technology). 



Overall, a substantial improvement could be achieved, whereas the lateral effect and low temperature 

operations remain the main limitations with regard to SOA. As shown in Fig. 11, including the lateral 

effects, the turn-off capability could be kept above 450 kVA /cm 2 at 125°C with a reduction down to 350 

kVA /cm 2 at 25°C. It is expected that, in the near future, this performance can be further improved based 

on the knowledge gained in establishing this new high power IGCT generation. 

New ANPC (Active NPC) topology 

Using power semiconductors with improved turn-off capability would not improve the output power 

substantially as the limitations set by the thermal management of the NPC topology cannot be overcome. 

By combining it with the advanced Active NPC topology the output power can be increased to 16 MVA. 

The Active NPC topology makes it possible to balance the semiconductor losses in the relevant IGCTs 

and diodes, thus differentiating this topology from the well-known NPC topology [6], for example at 

• a power factor equal to one 

• a high modulation and 

• delivering active power from DC to AC 

the thermal loading of pairs of outer and inner IGCTs (S1/S2 and S3/S4) of the ANPC IGCT PEBB can be 

equalized by distributing the turn-off switching actions needed to connect the outer potentials to the 

neutral potential. In case of inverse energy direction the same can be done to load the corresponding 

antiparallel diodes equally. 

Cd1 

Cd2 

Ls1 

Rcl1 

Rcl2 

Ls2 

ANPC IGCT PEBB 

Ccl1 

Ccl2 

Dcl1 

Dcl2 

Fig. 12: Active NPC IGCT PEBB Topology 

The ANPC IGCT PEBB 

S5 

S6 

D5 

D6 

S1 

S2 

S3 

S4 

D1 

D2 

D3 

D4 

Based on these basic innovations the ANPC IGCT PEBB has been developed. The mechanical 

arrangement is shown in Fig. 13. Overall the following improvements have been obtained: 

NPC IGCT ANPC IGCT 



Output power 100 % 180% 

Power density 

on stack level 

100 % 130 % 

Power density 

on inverter 

level 

100 % 150% on average 



Fig. 13: The ANPC IGCT PEBB (16 MVA PowerStack) 

Conclusions 

The IGCT is the leading technology in high power, medium voltage applications. The technology has been 

further developed and the maximum inverter output power without series connection has been increased 

by 80% with a parallel increase in the power density. 

Applying IGCT technology in the building of high power PEBBs makes it possible to deploy 

synergies of leading-edge PEBB designs over multiple applications due to defined interfaces and a 

platform-based based approach to power electronics systems. 

References 

[1] T. Ericsen, “Power Electronics Building Blocks”, The Electric Warship Conference, IME/IEE/SEE, London, 

1997 

[2] P. Steimer, “Power Electronics Building Blocks - a Platform-based Approach to Power Electronics”, IEEE 

Power Engineering Society, Toronto, 2003 

[3] IEEE Power Engineering Society, “Power Electronics Building Block (PEBB) Concepts”, IEEE Guide - Task 

Force 2 Wgi8 Document, Product Number 04TP170, 2004, contact: customer-service@ieee.org 

[4] P. Steimer, H.E. Grüning, J. Werninger, E. Carroll, S. Klaka, and S. Linder, “IGCT – A new emerging 

technology for high power low cost inverters,” in Conf. Rec. IEEE-IAS Annual Meeting, 1997, pp. 1592–1599. 

[5] T. Stiasny, P. Streit, M. Lüscher, M. Frecker, “Large area IGCTs with improved SOA“, Nuremberg, PCIM 

2004. 

[6] T. Brückner, S. Bernet, "Loss balancing in three-level voltage source inverters applying active NPC switches," 

in Proc. IEEE-PESC, Vancouver, Canada, 2001, pp. 1135-1140

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