Switched Doubly-Fed Machine Drive For High Power Applications · Switched Doubly-Fed Machine Drive...

Dr. Arijit Banerjee

Switched Doubly-Fed Machine Drive For High Power Applications

27th February, 2017

Department of Electrical and Computer Engineering

University of Illinois at Urbana-Champaign

88° East Latitude to 88° West Latitude

2

~ Mean Diameter of Earth

Barrackpore

Champaign

High-power motors are 1% of motor population but consume 45% of total motor energy

3

Power (horsepower)

0 %

100 %

< 20

50 %

[20, 200] > 200

International Energy Agency, 2011

Motor PopulationEnergy Consumption

(2.23 billion)(10000 TWh, 2012)

Wide range of applications for high power motors

4

Motion or

Process

High MW Converters, ABB, 2014

87% of high-power motors are directly connected to ac grid

5

Process

Control

Fixed Amplitude

&Frequency

Drawbacks:• 30% - 80% loss in control mechanism• Reactive power sink from Ac grid perspective

Variable speed drives are advantageous for process control

6

Control

The Office of EERE, DOE , 2015

Process

Control

Estimated annual benefits just in U.S. • Energy savings - $2.7B • Carbon emission reduction - 27 million tons

Anatomy of a variable speed drive

7

Filter Switch Filter Switch Filter

Fixed AC DC

VariableAC

State-of-the-art: High-power variable speed drive topologies

8Kouro et al., IEEE IAS, 2012

• Series/parallel switches

• Multi-level converters

• Thyristor based Cyclo-converters

Example: Nine megawatt commercial variable speed drive

9MV7000 Brochure

18 feet

Volume: ~ 318 cubic metersWeight: ~ 6 metric tons

3.3 feet


10MV7000 Brochure

Multiple Switches & Low Switching Frequency


11MV7000 Brochure

Bulky Filter


12MV7000 Brochure

Significant Cooling

Doctoral Thesis objective

13

Reduce the size of the variable speed drive

&

provide reactive power support to the grid

Thesis approach: Doubly-fed machines

14

Stator

Rotor

PS

PR

PM = PS + PR

MechanicalPM

Pena et al., IEE Proceedings, 1996

Switched-Doubly-fed-Machine drive architecture

15

PS

PR

LowSwitch

High

AC Grid

Load

DC Source

OrShort

Variable Speed Drive

Morel et al., IEE Proceedings, 1998Leeb et al., Naval Engineers Journal, 2010Banerjee et al., IEEE IAS, 2015

Switch is turned "Low" during low-speed, low-power mode

16

PM = PR

PR

Switch

DC Source

Or Short

PS = 0AC Grid


LowHigh

Rotor port provides all the mechanical power

17

PM = PR

Power(normalized)

Speed (normalized)

0

-0.5

0.5

1

1.5

0.5 1 1.50

Low Speed

PS = 0

Switch is turned "High" during high-speed, high-power mode

18

Switch

PM = PS ± PR

PS = Constant

PR

AC Grid


LowHigh

DC Source

Or Short

0 0.5 1 1.5-0.5

0

0.5

1

1.5

0

-0.5

0.5

1

1.5

0.5 1 1.50

Rotor port processes only the differential power

19

PS = Constant

PR

High Speed

PMPower

(normalized)

Speed (normalized)

Size of variable speed drive reduces by two-thirds

20

0

-0.5

0.5

1

1.5

0.5 1 1.50

PM

PS


Rating

Banerjee et al., IEEE Trans. Industry Applications, 2015

PR

Power(normalized)

Speed (normalized)

Challenges

21

• Drive design

Challenges

22

• Drive design • Switch realization

Challenges

23

• Drive design • Switch realization• Seamless control

Challenges

24


• Grid interaction

Challenges

25


• Grid interaction• Drive topology comparison

Challenges

26


• Grid interaction• Drive topology comparison• DFM design considerations

Contributions

27



Drive Design: Minimize variable speed drive rating

28

Current rating

Dc voltage

TransitionspeedReactive power

capability

MaximumspeedVoltage rating

subject to:1. Machine operating within its rated condition2. Matches drive torque-speed requirement3. Available ac source

Choice of stator flux drives the entire VSD design space

29

Low High

Ro

tor

Vo

ltag

e (p

.u)

Rotor Speed (p.u)

∝ Stator Flux

Low-speed mode stator flux = High-speed mode stator flux

= relative speed X flux

VSD “current rating” is driven by high-speed mode torque

30

Low High

Ro

tor

Vo

ltag

e (p

.u)

Rotor Speed (p.u)

∝ Stator Flux

Rotor Speed (p.u)To

rqu

e (p

.u)

Low-speed mode stator flux = High-speed mode stator flux

Low High

VSD “voltage rating” is driven by low-speed mode torque

31

Ro

tor

Vo

ltag

e (p

.u)

Rotor Speed (p.u) Rotor Speed (p.u)To

rqu

e (p

.u)

Low High

Low

High

Low-speed mode stator flux = 0.75 X High-speed mode stator flux

Non-idealities in DFM lead to design challenges for remaining within constraints

32

Low High

Ideal DFM

Ro

tor

Vo

ltag

e (p

.u)

Rotor Speed (p.u)

Acceleration

Deceleration

Ro

tor

Vo

ltag

e (p

.u)

Rotor Speed (p.u)

Practical DFM

A. Banerjee, M. S. Tomovich, S. B. Leeb and J. L. Kirtley, "Power

Converter Sizing for a Switched Doubly Fed Machine Propulsion Drive,"

in IEEE Transactions on Industry Applications, vol. 51, no. 1, pp. 248-258,

Jan.-Feb. 2015.

Contributions

33



Switch realization critical for smooth performance

34

S1 S2Switch A

B

C DC Source

Or Short


AC Grid

PM

All-Forced Commutation

C - Natural Commutation

B - Natural Commutation

C

A

BC

VAC

VDC A

B

AC

IS

Example: Dc-to-ac mode transition

35

DC AC

Initially :stator connected to dc source

Finally :stator connected to ac source

Goal :Natural commutation of all dc side SCRs simultaneously

Va

Vb

Vc

DFM MRotor

ConverterM

Vdc

Condition for natural commutation of A phase SCR

36

Va

Vb

Vc

DFM MRotor

ConverterM

Vdc


VAC

VDC



A

C

B

A

BC

AC

IS

A DC AC




X

P

Condition for natural commutation of B phase SCR

37

Va

Vb

Vc

DFM MRotor

ConverterM

Vdc


VAC

VDC



A

C

B

A

BC

AC

IS

B

DC AC




YQ

Condition for natural commutation of C phase SCR

38

Va

Vb

Vc

DFM MRotor

ConverterM

Vdc


VAC

VDC



A

C

B

A

BC

AC

IS




C

DC AC

ZR

Natural commutation of ABC phase SCRs simultaneously

39

Va

Vb

Vc

DFM MRotor

ConverterM

Vdc




C

A

BC

All - Natural Commutation

VAC

VDC A

B

AC

IS

A

B

C

S1 and S2 should not be ON simultaneously S1 and S2 should not be OFF simultaneously All phases switch together Minimal “supporting” circuitry Minimal perturbation on shaft behavior

Transfer scheme: dc to ac

DC AC

Prototype SCR-based Transfer Switch

40

Ac Source Dc Source

DFM Stator SCR Gate Signal

Experimental Result: Dc to Ac Source Transition

41

Source voltage (V)

Dc

sid

e SC

R c

urr

ent

(A)

Ac

sid

e SC

R c

urr

ent

(A)

Time (ms) Time (ms)

Time (ms)

Alternative transfer switch topology

42

Banerjee et. al. "Solid-State Transfer Switch

Topologies for a Switched Doubly Fed Machine

Drive," in IEEE Transactions on Power

Electronics, Aug. 2016.

Banerjee et. al., "Bumpless Automatic Transfer

for a Switched-Doubly-Fed-Machine

Propulsion Drive," in IEEE Transactions on

Industry Applications, July-Aug. 2015.

Contributions

43



Challenge: Seamless performance across entire speed range

44

0

-0.5

0.5

1

1.5

0.5 1 1.50

PM

PS

Mode Transition

Instant

Power(normalized)

Speed (normalized)

PR

Common framework for control and transition analysis

45

Doubly-fed

Machine

stator shaft

rotor

Ac Source

ShortOR

Dc Source

Control Port

Drive Torque/Speed

Shaft (1)Stator (2) Rotor (2)

State variables

SpeedD-axis currentQ-axis current

Stator flux - magnitude- angle

Transfer Switch

Stator flux transition model

46

2

cos1

sin0

ss so s m

ss

s rd

so sBso

s s

rV r x

xdx i

V rdt

so soV

0.1 0

1 1

, low speed mode (dc source)

, high speed mode (ac grid)

Disturbance

Initial condition

s

Pre-transition stator flux magnitudeInstant of transition (SCR switch)

ird

0 0 , low speed mode (shorted)

Phase plane captures machine dynamics in low speed mode

47

Magnitude

Angle

0.5

1.5

1

0 π/2π/4

Steadystate

Banerjee et al., IEEE Trans. Industry Applications, 2015-- , ITEC, 2015

(φX, φY)

(φX, φY)

Phase plane captures machine dynamics in high speed mode

48

Magnitude

Angle

0.5

1.5

1

0 π/2π/4

Steady state

(φX, φY)

(φX, φY)

Example: Low-to-high speed mode transition

49

Magnitude

Angle

0.5

1.5

1

0 π/2π/4

Target steady state

(φX, φY)

(φX, φY)

Initial condition

Switch timing is critical for smoother transition

50

0.5

1.5

1

0 π/2π/4

Switch Timing

Magnitude

Angle

(φX, φY)

(φX, φY)

Autonomous behavior during mode transition using the switch timing

51

0.5

1.5

1

0 π/2π/4

Magnitude

Angle

(φX, φY)

(φX, φY)

Torque bump

Maximum damping enables smooth transition from AC grid perspective

52

0.5

1.5

1

0 π/2π/4

Maximum Damping

Magnitude

Angle

(φX, φY)

(φX, φY)

Banerjee et al., APEC, 2016

Variable Speed Drive Limits

Rotor Current LimitStator

Current Limit

Mode Transition: Mapping of Operating Point on the State-plane

53

0 0.5 1 1.5 20.5

0.7

0.9

1.1

1.3

1.5

SS

Sho

rt

0 0.5 1 1.5 20.5

0.7

0.9

1.1

1.3

1.5

SS

0 0.5 1 1.5 20.5

0.7

0.9

1.1

1.3

1.5

SS

Dc

sou

rce

Low-speed operation High-speed operation

OR

Banerjee et. al., "Control Architecture for a

Switched Doubly Fed Machine Propulsion

Drive," in IEEE Transactions on Industry

Applications, March-April 2015.

Contributions

54



Laboratory-scaled power system as experimental setup

55

Generators (AC Grid)

T

Switch

Variable Speed Drive Machine + Load

Designed and built entire power system as laboratory setup

TI C2000DFM (1.1 kW)PM Gen.

DC Electronic Load Bank

Drive End Inverter

(Variable voltage

variable frequency)

Three phase

SCR based

Transfer

Switch

Dc Source

CUI VGS-100-24

20 V

MGEN

PMSG

DFM

600 W Electronic

Load Bank

BK Precision 8512

(Controlled current

mode)

D4

C1

R2

S2

D3

Diode

Bridge

LC-Filter

Phase

sequence

change

over

relay

Front End Inverter

(Variable voltage

variable frequency) R1

S1

Generator 1

Generator 2

Prime

Mover

Prime

Mover

Ac grid: 146 V, 40 Hz

Generators (1.4 kW)

Grid-side Conv.

6 Machines5 Control platforms (TI, NI, Matlab RTW, PSoC)3 Data acquisition systems2 Converters + Filters

Experimental Results: Full Torque/Speed Range Operation

57


58

0 5 10 15-2000

0

2000

0 5 10 15-5

0

5

Reference

Actual

Rotor speed (rpm)

Time (s)

Drive torque (Nm)


59

0 5 10 15-2000

0

2000

0 5 10 15-5

0

5

Reference

Actual

Rotor speed (rpm)

Time (s)

Drive torque (Nm)

Experimental result: Seamless mechanical port

60

0 1 2 3 40

0.53

1

1.5

Time (s)

1

0

0.53

0 1 2 3 4

Low Speed

High Speed

1.5 ReferenceActual

Transition Speed

Speed(normalized)

Experimental result: Seamless mechanical port

61

0 1 2 3 40

0.53

1

1.5

1

0

1.5

0.53

0 1 2 3 4

0.75 0.95 1.15

3

4

Low SpeedTorque Limit

High Speed Torque Limit1

0.75

0.750.55 0.95

Low Speed

High Speed

Time (s)

Speed(normalized)

Torque(normalized)


62

DFM active power (W)

0 5 10 15-600

-400

-200

0

200

400

600

800

rotor

stator

Time (s)

0 5 10 15-600

-400

-200

0

200

400

600

800


63

DFM active power (W)

rotor

stator

Time (s)

0 0.53 1 1.5-350

0

350

700

1050

Experimental result: Seamless electrical ports

64

Stator


0 1.5

ActivePower

(normalized)

0

-0.5

1.5 Total Power

0.5

1

0.53 1

Low Speed High Speed

Speed (normalized)


65 Time (s)

0 5 10 1580

85

90

95

0 5 10 1539

40

41

42

Grid voltagemagnitude (V)

Grid frequency (Hz)

Experimental Results: Speed Reference Oscillation

0 1 2 3 4 5 6 7 8600

800

1000

0 1 2 3 4 5 6 7 895

100

105

0 1 2 3 4 5 6 7 880

85

90

0 1 2 3 4 5 6 7 839

40

41

2

1

Rotor speed(rpm)

Dc link voltage(V)

Grid voltage magnitude(V)

Grid frequency(Hz)

Time (s)38

ActualReferenceHigh speedmode

Low speedmode

Experimental Results: Load Torque Oscillation

0 1 2 3 4 5 6 7 8700

800

900

0 1 2 3 4 5 6 7 895

100

105

0 1 2 3 4 5 6 7 880

85

90

0 1 2 3 4 5 6 7 839

40

41

Time (sec)

1

2Rotor speed

(rpm)

Dc link voltage(V)

Grid voltage magnitude(V)

Grid frequency(Hz)

Time (s)39

Load torque ON Load torque OFF

High speedmode

Low speedmode

Conclusion

68

• Two-thirds size reduction• Grid-friendly• Better efficiency• Reduced cost• Better reliability

Switched Doubly fed machine drive

Publications

69

2013

Power converter sizing

Control architecture

12-SCR Based transfer switch

Fault tolerant capability

Comparison of topology

Grid-friendly operation

Conference Journal

2014

Jan ’15

Jul ’15

Mar ’15

2016 Sep ’168-SCR Based transfer switch

Acknowledgment

Mike Tomovich, S.M. Arthur Chang, Ph.D.North Surakit., S.B. Prof. Al Avestruz

Prof. J. Kirtley Prof. S. Leeb Prof. J. Lang

The Grainger Foundation

Dr. Manny Landsman (Fellowship)

Prof. D. Perreault

71

It’s about the journey not the destination

Thank you!

Back up

72


73

stator

rotor

Time (s)

0 5 10 1596

98

100

102

104

0 5 10 15-2

0

2

4

Dc link voltage (V)

Dc link current (A)


74 Time (s)

0 5 10 15

0

500

1000

1500

2000

Generator 2

Generator 1Generator Active power (Watt)

Total

Future Work

75

Energy HarvestingTransportation Industrial Drives

• DFM electromagnetic design optimization• Evaluation in a MW-scale application• Brushless operation

Contributions

76

• Design methodology of a switched-DFM drive based on a requireddrive torque capability

• Solid-state transfer switch architectures for on-the-fly reconfigurationof the DFM

• Control platform for a seamless operation of the drive at themechanical and electrical ports

• Enabling reactive power support to the grid without adding extrapower electronics

• Performance comparison of different switched-DFM drive topologyleading to machine design guidelines

Additional Publications

77

(To be submitted)

Single sided induction heating

Uniform heating + optimized winding

MIT Cheetah robotic actuator design

2014

IECON'2013

2012

Comparison of induction motor technology

78

0

2

4

6

8

10

Cage-rotor Doubly-fed

Weight (Metirc Tons) Volume (Cubic Meters)

Specification: 1250 HP, 4160 V, 900 rpm, Air-cooled

TECO Westinghouse JH12508 Induction Motor GE 8411S Slip-ring Induction Motor

Comparison: PMSG + full converter relative to DFM + partial converter for wind power generation

79

0

0.2

0.4

0.6

0.8

1

1.2

1.4

Volume Weight Cost Losses

Specification: 3 MW, 90 rpm

Polinder et al., IEEE Transactions on Energy Conversion, Sept. 2006.

$4.5 B Worldwide Market in MV Motors

Market breakdown in 2012. Industry Sector by Revenues ($M) and Growth (%)

Agarwal et al., NIST/DOE Workshop NGEM, 2014

Research theme

81

Information World

PhysicalWorld

Energy Conversion Systems

Power Electronics

Electromagnetics

Control

Motors + Energy Storage

82

m

g

N

S

Rotor

S

N

Medium voltage motors market: $4.5 B Worldwide

0

6%

1200 $M

600 $M

10%

2%

Industrial sectors

Revenues Growth

Electromechanical Actuators 101

84

2 Degrees of Freedom 3 Degrees of Freedom 4 Degrees of Freedom

Torque production mechanism and control

85

Stator flux aided by the dc source controlled by the rotor d-axis current

Torque current controlled by the rotor q-axis current

Stator flux controlled by the rotor d-axis current

Torque current controlled by the rotor q-axis current

Low speed induction Low speed synchronous

Example 1 : 3.3 kV, 20 MW Induction Motor Drive (Propulsion application)

Volume: 28 Cubic MetersWeight: 11 Metric Tons

Water-Cooled

5

Source: ACS6000, MV7000 Medium Voltage Drive Brochure; Lewis et.al, Advanced Induction Motor


Air-Cooled AIM, 180 rpm

Example 2 : 3.7 kV, 20 MW Induction Motor Drive


Water-Cooled

5

Source: Hebner et.al, Design and analysis of a 20 MW Propulsion power train, 2004


Water-Cooled PM, 150 rpm

Ship efficiency improvement due to electrification

88

40

25

10 50 100Percentage Loading

Efficiency (Diesel

to Propeller)

Enabling technology drives what is possible with electromechanical energy systems

89

Power Semiconductor

Devices

Power Networks

Additive Manufacturing

(e.g. 3d printing)

Process linemanufacturing

Old Power Network

Seamless dynamic performance across entire speed range

90

0 2 4 6 80

650

1200

1800

2000

Time (s)

0.53

0

1

2 64

1.5Reference

Actual

Speed(normalized)

80

LowSpeed

HighSpeed

0 1 2 3 4 5 6 7 8700

800

900

0 1 2 3 4 5 6 7 895

100

105

0 1 2 3 4 5 6 7 880

85

90

0 1 2 3 4 5 6 7 839

40

41

Time (sec)

1

2

Severe Test: Mimics a ship in a turbulent weather

91

Propeller Out

Propeller In

Low Speed

High Speed 0.61

0.53

0.45

NormalizedSpeed

Time (s)0 2 4 6 8

0 1 2 3 4 5 6 7 8700

800

900

0 1 2 3 4 5 6 7 895

100

105

0 1 2 3 4 5 6 7 880

85

90

0 1 2 3 4 5 6 7 839

40

41

Time (sec)

1

2

Stable AC generator under severe mode swinging

92

0 1 2 3 4 5 6 7 8700

800

900

0 1 2 3 4 5 6 7 895

100

105

0 1 2 3 4 5 6 7 880

85

90

0 1 2 3 4 5 6 7 839

40

41

Time (sec)

1

2

0 1 2 3 4 5 6 7 8700

800

900

0 1 2 3 4 5 6 7 895

100

105

0 1 2 3 4 5 6 7 880

85

90

0 1 2 3 4 5 6 7 839

40

41

Time (sec)

1

2

Propeller Out Propeller In

Low Speed

High Speed

1.06

1

0.94

1.02

1

0.98

0.61

0.53

0.45

NormalizedSpeed

NormalizedAC

Generator Voltage

NormalizedAC

Generator Frequency

Time (s)0 2 4 6 8

Proposed power flow architecture: Prior Art

93

Time (s)

Normalized Speed

Morel, 1998

Actual

Mode Transition

0

1

Standard Variable Speed Drive

Power Electronic Devices

94

Experimental results: Stator flux transition

95

0.9 1 1.1 1.2 1.3 1.4 1.5 1.60.4

0.5

0.6

0.7

0.8

0.9

1

delta (rad)

Sta

tor

flu

x (

p.u

)

1 1.05 1.1 1.15 1.2 1.25 1.3 1.35 1.4 1.45 1.50.4

0.5

0.6

0.7

0.8

0.9

1

delta (rad)

Sta

tor

flu

x (

p.u

)

0 1 2 3 4 5 6 7 8700

800

900

0 1 2 3 4 5 6 7 895

100

105

0 1 2 3 4 5 6 7 880

85

90

0 1 2 3 4 5 6 7 839

40

41

Time (sec)

1

2

Severe Test: Mimics a ship in a turbulent weather

96

Propeller Out

Propeller In

Low Speed

High Speed 0.61

0.53

0.45

NormalizedSpeed

Time (s)0 2 4 6 8

0 1 2 3 4 5 6 7 8700

800

900

0 1 2 3 4 5 6 7 895

100

105

0 1 2 3 4 5 6 7 880

85

90

0 1 2 3 4 5 6 7 839

40

41

Time (sec)

1

2

Stable AC generator under severe mode swinging

97

0 1 2 3 4 5 6 7 8700

800

900

0 1 2 3 4 5 6 7 895

100

105

0 1 2 3 4 5 6 7 880

85

90

0 1 2 3 4 5 6 7 839

40

41

Time (sec)

1

2

0 1 2 3 4 5 6 7 8700

800

900

0 1 2 3 4 5 6 7 895

100

105

0 1 2 3 4 5 6 7 880

85

90

0 1 2 3 4 5 6 7 839

40

41

Time (sec)

1

2

Propeller Out Propeller In

Low Speed

High Speed

1.06

1

0.94

1.02

1

0.98

0.61

0.53

0.45

NormalizedSpeed

NormalizedAC

Generator Voltage

NormalizedAC

Generator Frequency

Time (s)0 2 4 6 8

Transition trajectory causes massive power swing at the grid and torque bump at the shaft

98

InitialCondition

0.5

1.5

1

0 π/2π/4 3π/4

Torque bump

2

Magnitude

Angle

(φX, φY)

(φX, φY)

Target steady state

Sizing comparison: High-power motors and variable speed drive

99

Motors Drive

Specification: 1250 HP, 4160 V, Air-cooled

Medium voltage High Efficiency Induction Motors, TECO Westinghouse price bookABB ACS1000 Industrial Drive

Machine design: 30 MW, 200 rpm, 4160 V, 60 Hz

100

Parameter Value

No. of pole 54

Stator rated current

2775 A

Rotor-to-stator turns ratio

2

Air gap flux density 0.75 T

Stator and rotor volume current

densities

6.5 A/mm2

Active length 2.55 m

Stator outside diameter

2.75 m

Rotor inside diameter

2.4 m

Rotor magnetizing current

480 A

Rotodrive: Induction/grid connected mode

12

a, b: Mechanical Switch

L. Morel IAS Transaction, Jul 1998

Used as discrete operation regimes

13

Hydro-electric power station Starting method for drives

Xibo Yuan, IAS Transaction, June 2011François BONNET, ECPE, Sept 2007

Ship Propulsion: Synchronous/grid connected mode

14

Steven Leeb & James Kirtley et al., Naval Eng. Journal, June 2010

Seamless grid interaction to ensure stability of the ac grid

104

0

-0.5

0.5

1

1.5

0.5 1 1.50Po

wer

(no

rmal

ized

)Speed (normalized)

PRPS

PM

PM

Seamless grid interaction to ensure stability of the ac grid

105

0

-0.5

0.5

1

1.5

0.5 1 1.50Po

wer

(no

rmal

ized

)Speed (normalized)

PRPS

PGPG

Solution: No intermittent energy storage in the variable speed drive

Front-end converter

Drive-end converter

Coordinated Front-end converter control

106

Current control

dqabc

Grid voltageangle

Ref. q-axiscurrent

Reactive power

controller

Ref. Reactive Power

demand

Dc link voltage

controller

Ref. Dc linkvoltage

Actualdc link voltage

Ref. d-axiscurrent Front-end

converter

Stator & rotor active power

Stator & rotor reactive power

Three-phase

PLL

Grid voltage angle &

frequency

Braking resistor

command

Stator & rotor

active power

Ac grid voltage

Contributions

107



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