Block seminar Modeling and control of wind turbine systems: An introduction

Transcription

1 Block seminar Modeling and control of wind turbine systems: An introduction Christoph Hackl (TUM) Munich School of Engineering (MSE) Lecture at Stellenbosch University: Modeling of core components on machine and grid side Christoph Hackl: Modeling and control of wind turbine systems: An introduction Page 1/23

2 Outline of the block course: Modeling and control of wind turbine systems: An introduction Date Time Content :00 15:30 Modeling of core components on machine and grid side :00 10:30 Controller design on machine and grid side :00 15:30 Controller design for the DC-link and power flow Modeling and control of wind turbine systems: An introduction, C. Hackl 2/23

3 Outline of 1. Lecture ( ) 1 Core components and motivation Overview What s inside a wind turbine system? Motivation: Why should we (also) focus on controls? 2 Modeling of core components Core components (electrical engineer s point of view) Regimes of operation Modeling of the turbine Modeling of grid-side electrical network Modeling of machine-side electrical network/generator Modeling of the inverter(s) Modeling of the DC link Modeling and control of wind turbine systems: An introduction, C. Hackl 3/23

4 Overview What core components do we have? Modeling and control of wind turbine systems: An introduction, C. Hackl 4/23

5 What s inside a wind turbine system? Inside a wind turbine (movie) ( Modeling and control of wind turbine systems: An introduction, C. Hackl 5/23

6 Distribution of failures in different sub-components control system electrical system sensors 10% 18% 23% 4% generator 4% 2% gearbox 6% 9% drive train mechanical break hydraulic system 8% 7% 5% rotor blades 4% rotor hub structural parts/housing yaw system Modeling and control of wind turbine systems: An introduction, C. Hackl 6/23

7 Failure rates and downtimes generator gearbox drive train rotor blades rotor hub structural parts mechanical break yaw system control system electrical system sensors hydraulic system failure rate turbine year Average down time (during life span of 20 years): Electrical system: 18.9 days Control system: 16.7 days Gear: 13.6 days downtime rdayss Modeling and control of wind turbine systems: An introduction, C. Hackl 7/23 ı

8 Core components (electrical engineer s point of view) Turbine Gear Generator Back-to-Back Converter Filter PCC Trafo Grid ω T ω M Rotor Stator β ref β ω M s abc M i abc M s abc N u DC i abc F u abc N,verk Control system β ref ω M,ref u DC,ref Q ref Q P ref P Operation management v W Q ref P ref Modeling and control of wind turbine systems: An introduction, C. Hackl 8/23

9 Regimes of operation of wind turbine systems I II III IV P N PT [W] v cut in v N v cut out v W [ Modeling and control of wind turbine systems: An introduction, C. Hackl 9/23

10 Modeling of the turbine Energy/power in wind Extractable power: Power coefficient Turbine torque Modeling and control of wind turbine systems: An introduction, C. Hackl 10/23

11 Power coefficient (without pitch control) Power coefficient cp [1] c P,1 p q c P,Betz Tip speed ratio λ r T ω T v W [1] Modeling and control of wind turbine systems: An introduction, C. Hackl 11/23

12 Power coefficient (with pitch control) 0.6 c P,1 p q c P,2 p, q 0.4 [1] λ r T ω T v W [1] β [ ] Modeling and control of wind turbine systems: An introduction, C. Hackl 12/23

13 Munich School of Engineering Wind turbine systems with synchronous generators Wind turbine SWT Direct drive (Permanent-magnet synchronous generator (PMSG)) Modeling and control of wind turbine systems: An introduction, C. Hackl 13/23

14 Overview: Electrical network of wind turbine systems Machine/generator-side grid-side (with ideal grid voltage) u a s u a F e a s R s L a s U i a s p G ` ` p N i a F U L F R F u a 0 o G e b s e c s R s R s L b s L c s V i b s W i c s i G u DC i i N DC C DC p DC i b F L F R F u b 0 V i c F L F R F u c 0 W o N o DC PCC Modeling and control of wind turbine systems: An introduction, C. Hackl 14/23

15 Modeling of grid-side electrical network in pa, b, cq u a F ` ` i a F U L F R F u a 0 i G u DC i DC CDC i N i b F L F R F u b 0 V o N i c F L F R F u c 0 W o DC PCC Using Kirchhoff s voltage and current law, we obtain goal: Model in pd, qq-coordinate system. How to achieve? Modeling and control of wind turbine systems: An introduction, C. Hackl 15/23

16 Space vector theory: A brief review u v w b q q 1 β ψ s r ω k 9 φ k d φ k d 1 ω r 9 φ r b r a r a b r b φ s a r a φ r α c r c c r c Modeling and control of wind turbine systems: An introduction, C. Hackl 16/23

17 Modeling of the (ideal) grid voltage u abc 0 u a 0 β ω k ω 0 u b 0 t u c 0 q u s 0 d φ k φ 0 u abc where 0 pu a 0, u b 0, u c 0q J cospω 0t ` α 0 q û 0 cospω 0 t 2{3π ` α 0 q cospω 0 t 4{3π ` α 0 q û 0? rvs ω 0 2π 50 rrad{ss (here: α 0 π{4 rrads) b c u s 0 û 0 φ 0 ş ω 0 dτ ` α 0 α a and φ 0 atan2 u α 0 u β Modeling and control of wind turbine systems: An introduction, C. Hackl 17/23

18 Modeling of grid-side electrical network in pd, qq Using voltage orientation, we end up with Modeling and control of wind turbine systems: An introduction, C. Hackl 18/23

19 Modeling of machine-side electrical network/generator u a s e a s R s L a s U i a s ` ` o G e b s R s L b s V i b s i G u DC i i N DC C DC e c s R s L c s W i c s o DC We only consider permanent-magnet synchronous generators (PMSG). Using Kirchhoff s voltage and current law, we obtain Goal: Model in pd, qq-coordinate system, i.e. rotor flux orientation. How to achieve? Modeling and control of wind turbine systems: An introduction, C. Hackl 19/23

20 Modeling of the inverter(s): Electrical network ` 2-Level-Inverter (ideal) i DC i N s a s b i a s c U u ab u DC s a s b i b s c i c V u bc W u ca o DC s abc : ps a, s b, s c q J What voltages can we apply? E.g. what happens for s abc p1, 0, 0q J? Modeling and control of wind turbine systems: An introduction, C. Hackl 20/23

21 Switching vectors and voltage hexagon b β u DC u u DC ps abc q J P t100,..., 111u u u DC u 011 1? 3 u DC 1 u 000 u2 111 u DC u 100 u DC 1 u 1 u 23 u 0 3 DC u 2 DC DC 3 DC 3 u DC α a 13 u DC u u u 101 DC Modeling and control of wind turbine systems: An introduction, C. Hackl 21/23

22 Delayed voltage response 600 u a ref u a (aus Umrichter) u a av (gefilterte Grundwelle) [V] Zeit t [s] (T PWM = 0,002 s) T dead T PWM ùñ F Inverter psq : ua,b,c psq u a,b,c ref psq e stdead «1 1 ` st dead Modeling and control of wind turbine systems: An introduction, C. Hackl 22/23

23 Modeling of the DC-link p G ` ` p N i G u DC i N i DC CDC p DC How may we model the DC-link dynamics? Modeling and control of wind turbine systems: An introduction, C. Hackl 23/23