Power Conversion Group School of Electrical and Electronic Engineering The University of Manchester, UK DFIG Wind Turbine Control System Co-ordination

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

Documents

Power Conversion Group School of Electrical and Electronic Engineering The University of Manchester, UK DFIG Wind Turbine Control System Co-ordination