power conversion group school of electrical and electronic engineering the university of manchester,...

Power Conversion GroupSchool of Electrical and Electronic EngineeringThe University of Manchester, UK

DFIG Wind Turbine Control System Co-ordination to improve Drive-

Train Reliability

Ting Lei1, M Barnes1, Sandy Smith1

1University of Manchester


Overview

Reliability of wind turbine subassemblies

DFIG wind turbine model

Basic control system

Mechanical & electric torque oscillations

Modified control schemes & protection circuit

Improvement through control coordination


WT Subasembly Reliability


Converter control

Mechanical control

DFIG Wind Turbine – overall control system

ωrβ

Pitch Controller

Te_refController

RSC controller

GSC controller

Te *

Grid operatorcontrol system

Qg * Vdc

*

ir_abc

` Vdc

ig_abc

`

Pe , Qg

DFIG

~ ~

ExternalGrid

_ _ _ _

GearBox

RSC GSC

is_abc

ig_abcir_abc

PWM PWM


KS

DG DT

DT-G

PSCAD Set up –2-mass shaft model

VwVs_b

Vs_c

Vs_a

Vr_

b

Vr_

a

Vr_

cIM

WTAerodynamic

Model (Tm_LSS)

Ta

Pitch Controller

ωr

maxωrMultimass(IndM/c)

WpuTeTL

Crow-bar

Rcb

Scb

ir_b

ir_a

ir_c

HG HT

Tm_LSS ≈ Ta : input

ωr_T

∆TtwistTele

ωr_G


Converter Control System – RSC

*Q sQPI

ˆˆ

sLm

*T eTPI

Te

Qs

Power control

*_ir q

_ir dPI

_ˆ ˆˆslip c r qL i

_ir qPI

ˆˆ ˆ

ˆm

slip sss

L

L

_ˆ ˆˆslip c r dL i

ˆ _vr d

ˆ _vr q

dqabc

ˆ _vr abc

RSC

Current control

*_ir d

_ir d

_ir q

d – loop

q – loop


Converter Control System – GSC inner loop

*dcV

DCPI

dcV

DC-linkcontroller

*_g qi

_g qi

_ig qPI

_ˆg qv

_ˆ ˆˆs gsc g dL i

_ˆg qe

*_g di

_g di

_ig dPI

_ˆg dv

_ˆ ˆˆs gsc g qL i

_ˆg de

dqabc

_ˆg abce

GSC

GSC current controller

d – loop

q – loop


Mechanical Control System

Converter Control

3 2,

2p

a wC

R v

wvaT

WT aerodynamic model

ωr

Plant

*PI

ωr_max

ωr

-11

1s

Actuator

r

eTωr*eT

WT Controller


Simulations with original controller

40% grid voltage drop for 0.5s

Wind step from 12m/s – 13m/s

10 15 201.19

1.21

1.23

10 15 20-1.0

3.5

8.0

10 15 200.95

1.20

1.45

10 15 200.998

1.000

1.002

Lumped shaft model 2-mass shaft model

Tm_LSS Tm_HSS

ωr (pu) Pitch angle (degrees) Torque (pu) Vdc (kV)

5 8 111.18

1.19

1.20

5 8 110.0

0.9

1.8

5 8 11-15

0

15

5 8 110.6

1.0

1.4

Tele Tm_HSS Tm_LSS

Ir_a Ir_b Ir_c

ωr (pu) Torque (pu) Vdc (kV)ir_abc (kA)


Basic controller bandwidths coordination

0.01 0.1 1 10 100 1000

Bandwidths (Hz)

Cont

rolle

r

PWM: 4500Hz

Grid f: 50Hz

Shaft natural f: 2.55Hz

GSC inner: 450Hz

RSC current :10Hz

DC-link: 10Hz

Pitch controller:

0.01 0.1 1 10100 1000

Bandwidths (Hz)

?


Controller bandwidths – pitch controller

10 23 361.180

1.215

1.250r(pu)

Time (s)

0.05Hz 0.10Hz 0.15Hz 0.25Hz


Basic controller bandwidths coordination

0.01 0.1 1 10 100 1000

Bandwidths (Hz)

Cont

rolle

r

PWM: 4500Hz

Grid f: 50Hz

Shaft natural f: 2.55Hz

GSC inner: 450Hz

RSC current: 10Hz

Pitch controller: 0.1 Hz

0.01 0.1 1 10100 1000

Bandwidths (Hz)

DC-link: 10Hz

d-current:10Hz

q-current:120Hz


Controller bandwidths – RSC inner-loop

RSC current controller d&q – 10Hz

RSC d – 10Hz q – 120Hz

5 8 111.18

1.19

1.20

5 8 110.0

0.9

1.8

5 8 11-15

0

15

5 8 110.6

1.0

1.4

Tele Tm_HSS Tm_LSS

Ir_a Ir_b Ir_c

ωr (pu) Torque (pu) Vdc (kV)ir_abc (kA)

5 8 111.18

1.19

1.20

5 8 110.0

0.9

1.8

5 8 11-15

0

15

5 8 110.6

1.0

1.4

Tele Tm_HSS Tm_LSS

Ir_a Ir_b Ir_c


Crow-bar protectionTimed crow-bar applied for 0.4s

Torque (pu) Vdc (kV)ir_abc (kA)ωr (pu) Pitch angle (degrees)

5.0 7.5 10.01.18

1.21

1.24

5.0 7.5 10.0-2.3

2.3

6.9

5.0 7.5 10.0-0.2

0.6

1.4

5.0 7.5 10.0-8

0

8

Tele Tm_LSS Tm_HSS

Ir_a Ir_b Ir_c

5.0 7.5 10.00.85

1.02

1.19

Minimum threshold crow-bar

5.0 7.5 10.01.18

1.21

1.24

5.0 7.5 10.0-2.3

2.3

6.9

5.0 7.5 10.0-0.2

0.6

1.4

5.0 7.5 10.0-8

0

8

5.0 7.5 10.00.85

1.02

1.19


Controller coordination

5.0 7.5 10.01.18

1.22

1.26

5.0 7.5 10.0-2.3

2.3

6.9

5.0 7.5 10.0-0.2

0.7

1.6

5.0 7.5 10.0-8

0

8

Tele Tm_LSS Tm_HSS

Ir_a Ir_b Ir_c

5.0 7.5 10.00.7

1.0

1.3Torque (pu) Vdc (kV)ir_abc (kA)ωr (pu) Pitch angle (degrees)

Damping mode

Damping controller setting

+

-

optr

PI

r

Look-Up

Table

wV *eT *

_r qiPI

eT

Normal

Fault

*_e faultT

+

-


Controller coordination

5.0 7.5 10.01.18

1.22

1.26

5.0 7.5 10.0-2.3

2.3

6.9

5.0 7.5 10.0-0.2

0.7

1.6

5.0 7.5 10.0-8

0

8

Tele Tm_LSS Tm_HSS

Ir_a Ir_b Ir_c

5.0 7.5 10.00.7

1.0

1.3Torque (pu) Vdc (kV)ir_abc (kA)ωr (pu) Pitch angle (degrees)

Damping mode

Damping disabled during fault

5.0 7.5 10.01.18

1.22

1.26

5.0 7.5 10.0-2.3

2.3

6.9

5.0 7.5 10.0-0.2

0.7

1.6

5.0 7.5 10.0-8

0

8

5.0 7.5 10.00.7

1.0

1.3


Drive-train reliability can be deteriorated by torque ripples in– Wind speed changes– Grid fault

A DFIG wind turbine model (PSCAD/EMTDC) is implemented for simulation, improvement is achieved by bandwidths coordination– RSC current-loop controller adjustment– Pitch controller adjustment

Crow-bar protection and damping control coordination– Minimum threshold crow-bar– Damping control disabled during fault– Soft resumption of damping control after fault

Future work – natural flux weakening, fast Pitch, different Winds

Summary

power conversion group school of electrical and electronic engineering the university of manchester,...

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