ifeec13 ftf based on dscc

8/14/2019 IFEEC13 FTF Based on DSCC

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Tokyo I nstitute of Technology

Power E lectronics Lab.

A Front-to-Front (FTF) System Consisting ofTwo Modular Multilevel Cascade Converters

Based on Double-Star Chopper-Cells

Firman Sasongko, Makoto Hagiwara, and Hirofumi Akagi

Tokyo Institute of Technology

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Outline

Research Background

Key Technologies for HVDC Network

FTF System Based on MMCC-DSCC

Simulation Results

Summary

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Research Background



Simulation Results

Summary

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Introduction

4

0

1

2

3

4

5

Annually added

Advantages

Higher wind speed

Less turbulence

Large areas availability

Less constructional and

operational restrictions

Challenges

Harsh environment

Remote

Limited accessibility

Installed offshore wind farm in Europe (GW)

Source: EWEA

0

1

2

3

New 2012

Source: GWEC

Offshore Wind Farm

Global offshore wind farm installed capacity in 2012 (GW)

1993 2002 2012


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Offshore Wind Farm Trend

further

fromshore

Monopile

0 ~ 30 m, 1 ~ 2 MW

Jacket/Tripod

25 ~ 50 m, 2 ~ 5 MW

Floating Structures

>50 m, 5 ~ 10 MW

Floating Structures

>120 m, 5 ~ 10 MW

Source: Principle Power

Challenges

deeper water (>50m)

more difficult bottom

conditions

higher waves

more robust wind

turbines necessity

power collection and

grid in terconnection

Reduce visual impacts ???

Increase the size ???

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Offshore Wind Farm Interconnection

AC/AC layout

AC/DC layout

DC/DC layout

Cable charging current

Limited voltage

regulation

Limited phase angle

difference

up to 155 kV, 100 km

AC voltage level

constraints

Higher flexibility and

reliability

DC Power Collection

6

100 ~ 1000 MW

[1] I. Erlich, F. Shewarega, C. Feltes, F. W. Koch, and J. Fortmann, Offshore wind power generation

technologies, Proceedings of the IEEE, vol. 101, no. 4, pp. 891905, Apr. 2013.

[6] S. Lundberg, Evaluation of wind farm layouts,EPE Journal, vol. 16, pp. 1421, 2006.


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High-Power Long-Distance Offshore Transmission

0

100

200

300

400

500

600

0 50 100 1 50 2 00 2 50 3 00 3 50 4 00

Cost

DistanceAC terminal

cost

AC line cost

DC terminal

cost

DC line cost

DC losses

AC losses

Total

AC

Cost

Total

DCCost

Power [MW]

Distance [km]

LCC-HVDC

VSC or LCC-HVDC

AC

Estimated Optimal Solution

for Offshore Transmission

7

AC vs. DC Transmission Cost

[i] M. Okba, M. Saied, M. Mostafa, et. al., High Voltage Direct Current Transmission A Review,

Part I,IEEE Energytech, pp. 17, May. 2012.

[2] N. M. Kirby, L. Xu, M. Luckett , and W. Siepmann, HVDC transmission for large offshore wind

farms,Power Engineering Journal, vol. 16, no. 3, pp. 135141, Jun. 2002.


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Research Background



Simulation Results

Summary

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Multi-Terminal HVDC Networks

9

Offshore Onshore

Stability Issue:

Fast fault interruption required


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DC Circuit Breakers

10

Mechanical

Switches Slow

Power

ElectronicsInefficient

ABBsbreakthrough: up to one gigawatt

with the interrupt time of 5 ms and

power loss less than 0.01%.

Hybrid

SystemFast and Efficient ?

Cost???


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Key Technologies for HVDC Networks

DC/DC Transformer

DC

DC Technicallyfeasible

Economicallyfeasible?

DC Circuit Breaker

Technicallyfeasible? Economicallyfeasible???

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Medium

FrequencyTransformerFault-ProtectiveDC/DC Converter ?


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Research Background



Simulation Results

Summary

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MMCC-DSCC Basic Principles

leg

arm

=

+

=

=

+

=

n+1 level

13

[13] R. Marquardt, A. Lesnicar, and J. Hildinger, Modulares stromrichterkonzept fur

netzkupplungsanwendung bei hohen spannungen, ETG-Conference, 2002.

[14] H. Akagi, Classification , terminology , and application of the modular multilevel cascade

converter (MMCC),IEEE tran. on power elect., vol. 26, no. 11, pp. 31193130, Apr. 2011.


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BTB and FTF System Applications

Aims

HVDC transmission

Frequency changer

Asynchronous power

flow controller

Aims

DC-to-DC systems

Galvanically

isolated systems

Voltage changer

Back-to-Back System

Front-to-Front System

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Front-to-Front (FTF) System Based on DSCC

Modular Structure & Redundant

Operation Bi-directional Power Flow

Inherent Faults Handling

Passive Components Reduction

DC AC DC

Multilevel Signal

Waveforms

Chopper Cell

n-CellsMedium FrequencyTransformer

Less Space

Less Weight

Lower Cost15

150 ~ 500 Hz


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Faults on an FTF System

16

ifault

Fault Protection: Handled by

circuit operation

Very fast

interruption

OFF OFF OFF

OFF OFF OFF

OFF OFF OFF

OFF OFF OFF


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Power Collection Based on FTF System

17

Collecting SideConverters

Transmission Side

Converter


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Research Background



Simulation Results

Summary

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Circuit Configuration for Simulation

6.6 kV 150 Hz

LAC: 0.37 mH (8%)LC: 1.1 mH (23.8%)

n: 16

DC Capacitors1.65 kV/3 mF

Switching MethodPhase-Shifted PWM

fc = 1350 Hz

Dead-time = 4 s

Vref

1:1

13.2 kV

P* :

10 MW

Power Control

- Decoupled Current

Control

Capacitor Control

- Leg Balancing

- Arm Balancing

- Individual Balancing

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-10

0

10

20 ms0

1.65

-10

0

10

-1.25

0

1.25

-0.75

0

0.75

-10

0

10

20 ms0

1.65

-10

0

10

-1.25

0

1.25

-0.75

0

0.75

Simulation Results

DSCC-1 DSCC-2Power

[MW]

Line

Voltages

[kV]

LineCurrents

[kA]

Leg

Capacitor

Voltages

[kV]

DC

Currents

[kA]

iZuiDC

vC1u vC9u

20

C ll i Si l i l


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-10

0

10

20 ms0

1.65

-1.25

0

1.25

0

1.65

0

1.65

Power Collection Simulation Results

Power

[MW]

Line

Currents

[kA]

DSCC-1

CapacitorVoltages

[kV]

DSCC-2

Capacitor

Voltages

[kV]

DSCC-3

Capacitor

Voltages

[kV]

P2* :8 MW

P3* :2 MW

vC1u1 vC9u1

vC1u2 vC9u2

vC1u3 vC9u3

p1p2 p3

iu1 iu2 iu3

6.6 kV 150 Hz

21

VDC: 13.2 kV

S


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Summary

HVDC transmission is likely to be preferred option for future

offshore wind farms.

Dc/dc transformers and dc breakers are the key components

to multi-terminal dc grid.

A front-to-front (FTF) system is a dc/dc transformer that is

capable of handling faults inherently.

The proposed FTF system based on MMCC-DSCC is

applicable for dc power collection.

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Thank you

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R f


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References

[1] I. Erlich, F. Shewarega, C. Feltes, F. W. Koch, and J. Fortmann, Offshore wind power generation

technologies,Proceedings of the IEEE, vol. 101, no. 4, pp. 891905, Apr. 2013.

[2] N. M. Kirby, L. Xu, M. Luckett, and W. Siepmann, HVDC transmission for large offshore wind farms,Power Engineering Journal, vol. 16, no. 3, pp. 135141, Jun. 2002.

[3] V. G. Agelidis, G. D. Demetriades, and N. Flourentzou, Recent advances in high-voltage direct-current

power transmission systems,IEEE International Conference on Industrial Technology, 2006. ICIT 2006.,

pp. 206213, Dec. 2006.

[4] A. M. Abbas and P. W. Lehn, PWM based VSC-HVDC systems - a review,PES 09. IEEE Power &

Energy Society General Meeting, 2009., pp. 19, Jul. 2009.

[5] J. Glasdam, J. Hjerrild, L. H. Kocewiak, and C. L. Bak, Review on multi-level voltage source converter

based HVDC technologies for grid connection of large offshore wind farms,IEEE International

Conference on Power System Technology (POWERCON) 2012, pp. 16, Oct. 2012.

[6] S. Lundberg, Evaluation of wind farm layouts,EPE Journal, vol. 16, pp. 1421, 2006.

[7] W. Lu and B.-T. Ooi, Premium quality power park based on multiterminal HVDC,IEEE Transactions on

Power Delivery, vol. 20, no. 2, pp. 978983, Apr. 2005.

[8] L. Xu, B. W. Williams, and L. Yao, Multi-terminal dc transmission systems for connecting large offshorewind farms, 2008 IEEE Power and Energy Society General Meeting - Conversion and Delivery of

Electrical Energy in the 21st Century, pp. 17, Jul. 2008.

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R f ( td)


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References (contd)

[9] J. Zhu and C. Booth, Future multi-terminal HVDC transmission systems using voltage source converters,

45th International Universities Power Engineering Conference (UPEC) 2010 , pp. 16, Aug. 2010.

[10] R. Marquardt, Modular multilevel converter topologies with dc-short circuit current limitation, 8thInternational Conference on Power Electronics ECCE Asia, pp. 14251431, Jun. 2011.

[11] S. Kenzelmann, A. Rufer, M. Vasiladiotis, D. Dujic, F. Canales, and Y. de Novaes, A versatile dc-dc

converter for energy collection and distribution using the modular multilevel converter,Proceedings of the

2011-14th European Conference on Power Electronics and Applications (EPE 2011), pp. 110, Aug. 2011.

[12] S. Kenzelmann, D. Dujic, F. Canales, Y. de Novaes, and A. Rufer, Modular dc/dc converter: comparison

of modulation methods, 15thInternational Power Electronics and Motion Control Conference

(EPE/PEMC) 2012, pp. LS2a.11LS2a.17, Sep. 2012.

[13] R. Marquardt, A. Lesnicar, and J. Hildinger, Modulares stromrichterkonzept fur netzkupplungsanwendung

bei hohen spannungen,ETG-Conference, 2002.

[14] H. Akagi, Classification , terminology , and application of the modular multilevel cascade converter

(MMCC),IEEE Transactions on Power Electronics, vol. 26, no. 11, pp. 31193130, Apr. 2011.

[15] H. Fujita, M. Hagiwara, and H. Akagi, Power flow analysis and dc capacitor voltage regulation for the

MMCC-DSCC,IEEJ Transactions on Industry Applications, vol. 132, no. 6, pp. 659665, Dec. 2012.[i] M. Okba, M. Saied, M. Mostafa, et. al., High Voltage Direct Current Transmission A Review, Part I,

IEEE Energytech, pp. 17, May. 2012.

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E Wi d F


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European Wind Farms

MMCC F il M b


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MMCC Family Members

Medium-Voltage High Power Converter

Voltage Source

Multilevel

Modular MultilevelCascade Converter

Double Arm

Star Connection

Chopper-Cells

Bridge-Cells

Single Arm

Star Connection

Bridge-Cells

Delta Connection

Bridge-Cells

CascadedH-Bridge

Diode-Clamped

FlyingCapacitor

Two-Level

Current Source

LoadCommutated

PWM

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A. Lesnicar, R.Marquardt, An Innovative Modular Multilevel Converter Topology Suitable for a Wide Power Range, IEEE PowerTech conf.,

2003.

Hirofumi Akagi, Classification, Terminology, and Application of the Modular Multilevel Cascade Converter (MMCC),IEEE trans. power

elect., vol.26, no. 11, 2011.

Modular Multilevel

Cascade Converter

Double-Star Chopper-Cells

(MMCC-DSCC)

Li i f AC C bl T i i C i


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Limits of AC Cables Transmission Capacity

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for three voltage levels, 132 KV, 220 KV and 400 KV

T. Ackermann, N. Barberis Negra, J. Todorovic, L. Lazaridis, Evaluation of Electrical Transmission Concepts for

Large Offshore Wind Farms, presented at the Copenhagen Offshore Wind -Int. Conf. Exhib., Copenhagen, Denmark,

Oct. 2005.

Chopper Cell Basic Operation


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Chopper Cell Basic Operation

S1 S2 iP vpi Capacitor C

ON OFF + vci charging

OFF ON + 0 -

ON OFF - vci discharging

OFF ON - 0 -

Cell Voltage

Command

AC Voltage

Command

Maintain AC

Side Voltage

DC Voltage

Command

Maintain DC

Side Voltage

Capacitor

Voltage

Command

Maintain

Capacitor

Voltage

output side

input side

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MMCC DSCC Control Method


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MMCC-DSCC Control Method

Controlling Output Power

DecoupledCurrent Control

Controlling Capacitor Voltage

Leg BalancingControl

Arm Balancing

Control

IndividualBalancing Control

iP,iN

VPi ,

VNi Cap. C

+ vci charging

- vci discharging

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Front to Front for DC/DC Application


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Front-to-Front for DC/DC Application

* S. Kenzelmann, D. Dujic, F. Canales, Y. de Novaes, and A. Rufer, Modular DC/DC converter:

Comparison of modulation methods, 15th International Power Electronics and Motion Control

Conference (EPE/PEMC) 2012, pp. LS2a.11LS2a.17, Sep. 2012.

Previous Research*

Single-Phase Configuration

Two-level & Square-wave

modulation

Our ResearchThree-Phase Configuration

Coupled Inductor

Sinusoidal Phase Shift Pulse Width

Modulation

Simulated and Experimental

Verification

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Fault on a Multilevel Converter


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AC

Fault on a Multilevel Converter

32

AC

Solutions:

1. DC Breakers2. Full-Bridge Cells

3. Parallel Thyristors

Circuit Configuration


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Circuit Configuration

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1:1

6.6 kV 150 Hz

LAC: 0.37 mH (8%)LC: 1.1 mH (23.8%)

n: 16

DC Capacitor1.65 kV/3 mF

Switching MethodPhase-Shifted PWM

fc = 1350 HzDead-time = 4 s

13.2 kV

P* :10 MW

Simulation Results


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-10

0

10

10 ms

0

1.65

-10

0

10

-1.25

0

1.25

-3

-2

-1

0

1

2

3

Simulation Results

34

DSCC-1 DSCC-2

Power[MW]

Line

Voltages

[kV]

Line

Currents

[kA]

Leg

Capacitor

Voltages

[kV]

DC

Currents

[kA]

iDCiZu

vC1u vC9u

-10

0

10

10 ms

0

1.65

-10

0

10

-1.25

0

1.25

-3

-2

-1

0

1

2

3

Short Circuit

Event

Experimental Setup 400 V 10 kW FTF System


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U-phase

Module Structure:

16 cells/leg

Chopper Cell:

150-V 70-A MOSFET42

50-V 6600-mF Capacitor

Experimental Setup 400 V 10 kW FTF System

Controller System:

- A DSP board

- Two FPGA boards

AC Voltage:

200 V 50 Hz

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Medium Frequency Transformer


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Medium Frequency Transformer

3 4

Volume and Frequency Relation:

U.Drofenik, A 150kW Medium Frequency Transformer Optimized for Maximum Power Density,7th

International Conference on Integrated Power Electronics Systems (CIPS12), 2012.

1 +

12 +

1

Winding Core Dielectric

Transformer Losses

36

ifeec13 ftf based on dscc

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