Block seminar Modeling and control of wind turbine systems: An introduction Christoph Hackl (TUM) Munich School of Engineering (MSE) 22.04.2014 1. Lecture at Stellenbosch University: Modeling of core components on machine and grid side 22.04.2014 Christoph Hackl: Modeling and control of wind turbine systems: An introduction Page 1/23
Outline of the block course: Modeling and control of wind turbine systems: An introduction Date Time Content 22.04.2014 14:00 15:30 Modeling of core components on machine and grid side 23.04.2014 09:00 10:30 Controller design on machine and grid side 29.04.2014 14:00 15:30 Controller design for the DC-link and power flow 22.04.2014 Modeling and control of wind turbine systems: An introduction, C. Hackl 2/23
Outline of 1. Lecture (22.04.2014) 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 22.04.2014 Modeling and control of wind turbine systems: An introduction, C. Hackl 3/23
Overview What core components do we have?... 22.04.2014 Modeling and control of wind turbine systems: An introduction, C. Hackl 4/23
What s inside a wind turbine system? Inside a wind turbine (movie) (http://www.youtube.com/watch?v=ng1ugt6qufm) 22.04.2014 Modeling and control of wind turbine systems: An introduction, C. Hackl 5/23
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 22.04.2014 Modeling and control of wind turbine systems: An introduction, C. Hackl 6/23
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 0.1 0.11 6 10 2 4 0.18 3.5 0.12 3.3 0.1 2.7 0.14 2.6 0.19 1.9 0.44 1.6 0.59 1.5 0.26 1.2 0.24 failure rate 6.2 5.7 1 turbine year 7.2 0 2 4 6 8 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 22.04.2014 Modeling and control of wind turbine systems: An introduction, C. Hackl 7/23 ı
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 22.04.2014 Modeling and control of wind turbine systems: An introduction, C. Hackl 8/23
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 [ 22.04.2014 Modeling and control of wind turbine systems: An introduction, C. Hackl 9/23
Modeling of the turbine Energy/power in wind Extractable power: Power coefficient Turbine torque 22.04.2014 Modeling and control of wind turbine systems: An introduction, C. Hackl 10/23
Power coefficient (without pitch control) Power coefficient cp [1] 0.6 0.4 0.2 c P,1 p q c P,Betz 0 0 2 4 6 8 10 12 14 16 18 20 Tip speed ratio λ r T ω T v W [1] 22.04.2014 Modeling and control of wind turbine systems: An introduction, C. Hackl 11/23
Power coefficient (with pitch control) 0.6 c P,1 p q c P,2 p, q 0.4 [1] 0.2 0 20 15 10 λ r T ω T v W [1] 5 0 60 40 20 β [ ] 0 22.04.2014 Modeling and control of wind turbine systems: An introduction, C. Hackl 12/23
Munich School of Engineering Wind turbine systems with synchronous generators 22.04.2014 Wind turbine SWT-2.3-113 Direct drive (Permanent-magnet synchronous generator (PMSG)) http://www.siemens.com/press/de/pressebilder/ http://www.siemens.com/press/de/pressebilder/ Modeling and control of wind turbine systems: An introduction, C. Hackl 13/23
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 22.04.2014 Modeling and control of wind turbine systems: An introduction, C. Hackl 14/23
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? 22.04.2014 Modeling and control of wind turbine systems: An introduction, C. Hackl 15/23
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 22.04.2014 Modeling and control of wind turbine systems: An introduction, C. Hackl 16/23
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? 2 230 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 0 22.04.2014 Modeling and control of wind turbine systems: An introduction, C. Hackl 17/23
Modeling of grid-side electrical network in pd, qq Using voltage orientation, we end up with... 22.04.2014 Modeling and control of wind turbine systems: An introduction, C. Hackl 18/23
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? 22.04.2014 Modeling and control of wind turbine systems: An introduction, C. Hackl 19/23
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? 22.04.2014 Modeling and control of wind turbine systems: An introduction, C. Hackl 20/23
Switching vectors and voltage hexagon b β u DC u 010 2 3 u DC ps abc q J P t100,..., 111u u 110 1 3 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 001 23 u u 101 DC 22.04.2014 Modeling and control of wind turbine systems: An introduction, C. Hackl 21/23
Delayed voltage response 600 u a ref u a (aus Umrichter) u a av (gefilterte Grundwelle) 400 200 [V] 0 200 400 600 0.02 0.025 0.03 0.035 0.04 0.045 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 22.04.2014 Modeling and control of wind turbine systems: An introduction, C. Hackl 22/23
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? 22.04.2014 Modeling and control of wind turbine systems: An introduction, C. Hackl 23/23