Advanced Power Electronics for HVDC Applications

Advanced Power Electronics for HVDC Applications

Michel Mermet-Guyennet

March 2015

Presentation Supergrid Institute

Applications : VSC HVDC & DCDC HVDC-MVDC

Energy efficiency : potential of SiC devices

Prospective on high voltage SiC devices

Conclusion

2

Overview

The Super GridAn electricity transmission system, mainly based on direct current, designed to facilitate large-scale sustainable power generation in

remote areas for transmission to centres of consumption, one of whose fundamental attributes will be the enhancement of the market in

electricity".

Friends of the supergrid

DC + dynamic stability management power electronics becoming key technology

Research programmes

1- The Grid: architecture, operation and control

2- Equipments for measurement and breaking

3- Equipments for power conversion

4- SuperGrid cables and lines

5- SuperGrid resources for stabilization and storage





Conclusion

5

Overview

TITRE DE LA PRESENTATION - INTERVENANT - DATE -

Off-shore wind farm connection

MaxSine® Valve Key Features

Coolant Return

Optical Fibre Routing

Coolant FlowBase Insulators

Inter-tier Insulators

Stress ShieldsIGBT1

IGBT2

R1

C1

D1

D2

T1

SW1

Sub-Module

VSC MMC

Consider a 1 GW transmission line

Consider the VSC MMC converter with 99% efficiency

Consider you sell electricity at 0,1 €/kWh

You loose 10 MW in nominal condition :

You loose 1000 € every hour in nominal condition per VSC (2000 € both ends)

You have to cool 10 MW of thermal power dissipation per converter (strong impact on acquisition cost and reliability of your VSC)

If you improve VSC efficiency by 0,1%

You gain 100€ every hour in nominal condition per VSC (200€ both ends)

You gain 438 000 € every year (based on 6 month nominal operation over one year)

You gain 876 000 € every year on both VSC converter !

9

What is at stake !


Example of topology for DC grid collector

A

DCDC made with DAB (Dual Active Bridge) with many options (resonant, multiple-phase, modulations, ...) coupled with Medium Frequency Transformer (working in kHz range).

Typical power of DCDC is 10 MW with voltage in MVDC range and high ratio of transformation but with isolation primary-secondary in HVDC range


lnnovative topologies and control of power converter for DC grid applications

Medium frequency transformer

High Voltage Silicon Carbide (SiC) technology and new generation of HV SiC components with packaging, gate-drive & passives

Design machine for power converter & MF transformer with virtual prototyping approach

Back to back MMC vs cascaded DCDC

ConverterTopology

Local Control

Objective FunctionsEfficiency

Link with DC GridControl

Constraint FunctionsHarmonic rejectionsExternal defaults=

lightning, short circuitFull operation time

Sub-systemPhysical Design

MFT Design

PE Design

SiCchips

PE DesignPack

PE DesignGateDrive

PE Caps or SSE

SySML

Multiphysics based design = MAXWELL3D – ANSYS3D

Mech+Therm-Q3D

Electric SimulatorSimplorer

PSIM

Control system SimulatorMATLAB-Simulink

Control Boards

EMTP-RVfor network simulation

VHDL-AMS

3D SolidCreo Essential II

Solid-Edge

Key technologies for future DC Grid





Conclusion

14

Overview

Si will be widely used in BV 15V-150V

SiC will be dedicated to HV BV 1,2 kV-20kV+ and high current 100A per chip. Fact is SiC thermal conductivity is three times higher than GaN thermal conductivity

GaN will adress the range BV 600V-1200V+ and nominal current 2-30A per chip in application with high cost constraint

15

SiC vs GaN (and others)

150V

Schottky Si

Transistor MOS

JBS SiC -> PiN

Switch SiC

Schottky GaN

Switch GaN

20kV+

Volt

100

2

30

0.6-1,2kV

Diamond - AlN

>2020

Nominal

current

per chip

(A)

Breakdown Voltage

SiC : breakthrough in MMC efficiency

16

INFINEON FZ1500R33HL3IGBT 3300V 1500A

CREE MOSFET 3300V 40 mOhms

- Two cases : 30 chips in parallel and 50 chips in parallel

- No additional diodes in anti-parallel = use of reverse conducting property of MOSFET

- Same characteristics reverse/direct

- Equivalent MOSFET = 3300V 1 mOhm

Characteristics 30 chips //

17

VDS (V)

I D(A

)

Total surface area of Si = 50 cm2

Total surface area of SiC = 14 cm2

Characteristics 50 chips //

18

VDS (V)

I D(A

)

Total surface area of Si = 50 cm2

Total surface area of SiC = 24 cm2

Loss calculation

- Two approaches:- Calculation of Power Losses for MMC-based VSC HVDC

Stations - Phil S Jones & Colin C Davidson

- Comparison of High Voltage Modular AC/DC converters –P. Ladoux, P. Marino, G. Raimondo, N. Serbia

- Application case for calculation:- P = 100 MW

- Vd =+- 160 kV

- Fsw=200 Hz

- Inverter mode

- M=0,85

- Vv=2000V

- Dynamic characteristics for SiC extrapolated Eon /5 Eoff/10

19

Static and dynamic losses

20

Temperature dependance of losses

21





Conclusion

22

Overview

Prospective view on HV SiC

Chips

Breakdown

Voltage

1700V 3300V 6500V 10 kV 15 kV 20 kV

Technology &

Status

MOSFET&JFET

40 mOhms

JBS 50A

MOSFET&JFET

40 mOhms

JBS 45 A

MOSFET ?

JBS ?

Bip based

PiN

Bip based

PiN

Bip based

PiN

Potential

development

chips

Available on the

market

Available on the

marketWill be available

on the market

Technology

development

Design and make

prototypes

Technology

develoment

Technology

development

Potential

development

multi-chips &

pack

-Paralleling for

low on state

-Fs to 40 kHz

-Reverse

conducting

-Paralleling for

low on state

-Fs to 40 kHz

-Reverse

conducting

-Auto supply

-Fail to short

Same as 3,3 kV -Paralleling for

low on state

-Fs to 30 kHz

-Auto supply

-Series

association of 3,3

kV

-Fail to short

Same as 10 kV Same as 10 kV

Product

objective

1500A -

1mOhm

250 A

2500A

24

10 kV Diodes

8 kV

10 kV

} Kimoto lab.

25

10 kV transistor

High On-resistance for 10 kV unipolar devices

Current control for BJT and Thyristor

Oxide reliability for IGBT

Merge between unipolar and bipolar devices

– Voltage or optical control

– Bipolar conduction : high current capability

26

Methodology for the best 10kV transistor structure

Epitaxial velocity : 10 µm/h industrially implemented

10 kV devices => 100 µm as thickness

=> Increase of the epitaxial velocity

Introduction of gaz with Cl

What is the impact on :

– Quality

– Carrier life time

– Morphology...

27

Technology improvement : thick epitaxy

High carrier life-time value : decrease on-state losses

Technological process : decrease value

Obtain a base material with the most important value

Very low Stacking Faults density

Develop a process with no degradation

28

Technology improvement : carrier life-time

Paralleling 30 to 50 chips (MOSFET) without degrading the switching characteristics : 3,3 kV 1500A 40kHz

Package topology, stray inductance, gate distribution

Solution is Integrated Switching Cell (ISC) including DC capacitor + MOS-Driver + Half-Bridge and full design of ISC

Technology development : packaging

HV et Medium Frequency Switching

LCC valves = series association of thyristors in « press-pack » technology

Very high availability due to automatic reconfiguration of series association in case of component failure = « fail to short » characteristic of press pack technology

It is a « must » to have this feature for HV SiC packaging :

In depth FMEA (Failure Mechanisms and Effect Analysis) of SiC technology mandatory = definition and test of « fail to short » for SiC devices

« Wire bond » lead to low I2t = double side soldering or « Press pack » solution to be adapted

Technology development : fail-to-short packaging

Existing IGBT BV is operational up to 6,5 kV for module and « press-pack » technology up to 10kV

Industrial experience on 6,5 kV IGBT module shows limitations in life-time and reliability :

Peripheral protection technology

Passivation technology

Packaging material technologies

Solutions for packaging SiC 10kV-15kV will include

Field grading will not be only in and on chips but also extended on packaging

Replacement passivation material for SiC (passivation material with higher di-electric strength)

Technology development : solutions for high voltage packaging (10kV-15kV)





Conclusion

32

Overview

In 1880, a journalist of Herald Tribune interviewed Thomas Edison about the light bulb and he said :

“After the electric light goes into general use, none but the extravagant will burn tallow candles.”

This affirmation has been transformed into :

“We will make electricity so cheap that only the rich will burn candles”

In 2015, we would like to hear:

“We will make the SiC power chip so cheap, none but the extravagant will continue to use silicon power chip”

33

Conclusion

Penser les réseaux électriques du futur

Soon : www.supergrid-institute.com

Documents

Advanced Power Electronics for HVDC Applications