Load Assumptions for the Design of electro mechanic Pitch Systems Andreas Manjock Germanischer Lloyd Industrial Services GmbH, Business Segment Wind Energy Andreas.Manjock@gl-group.com, www.gl-group.com/glwind

Load Assumptions for the Design of electro mechanic Pitch Systems Simulation Model Design Load Cases (DLCs) Data Postprocessing Conclusion and Outlook Source: ENERCON EWEC 2007

1.1 Pitch System Components Blade Bearing Gear Box Rotor Blade Drive Motor Symbol Definition JPD Moment of Inertia, Pitch Motor JRB Moment of Inertia, Rotor Blade iPD Ratio of Pitch Drive Gearbox iPB Ratio of Pitch Bearing Mesh iP Ratio of entire Pitch System iP JPD JRB iPB iPD Control Unit Pitch Controller EWEC 2007

Load Assumptions for the Design of electro mechanic Pitch Systems Simulation Model 2.1 Load Components 2.2 System Model 2.3 Local Model for Mesh Moment 2.4 Drive Motor Characteristics 2.5 Drive Motor Limitations 2.6 Drive Control Scheme Design Load Cases (DLCs) Data Postprocessing Conclusion and Outlook Source: ENERCON EWEC 2007

Blade Root Coordinate System 2.1 Load Components αP Blade Root Coordinate System MZB Symbol Definition αP Pitch Angle MPDA Pitch Drive Actuator Torque MZB Pitch Torque Rotor Blade MR Friction Torque Blade Bearing MR MPDA MR = M0 + µbend∙ Mres+ µaxial∙ Faxial+ µradial∙ Fradial Source: GL „Guideline for the Certification of Wind Turbines“, 2003 EWEC 2007

Global Simulation Model 2.2 System Model Structural Model Global Simulation Model Source: GH Bladed 3.67 i P 2 • J PD +J RB α •M PDA M R ZB •i ** EWEC 2007

2.3 Local Model for Mesh Moment Local MM - Assumption“ α +J RB •M M R ZB J •α P ** α P P i P •M PDA M J PD •i P 2 • α ** i 2 • J P PD Mass System Pitch Drive Mass System Rotor Blade Split of Mass System provides Loads for Drive Train Components MM = MZB+ JRB ∙ αP** - MR EWEC 2007

2.4 Drive Motor Characteristics iP  P MPDA Control Unit Pitch Controller Source: OAT Osterholz Antriebstechnik GmbH EWEC 2007

2.5 Drive Motor Limitations Source: OAT Osterholz Antriebstechnik GmbH EWEC 2007

2.6 Drive Motor Control Scheme Pitch Controller EWEC 2007

Load Assumptions for the Design of electro mechanic Pitch Systems Simulation Model Design Load Cases (DLCs) 3.1 Identified Load Cases 3.2 Fatigue DLCs 3.3 Extreme DLCs Data Postprocessing Conclusion and Outlook Source: ENERCON EWEC 2007

3.2 Identified Load Cases Fatigue Load Cases Extreme Load Cases DLC1.2 Turbulence State 1 2 m/s 57.0% idling 5 30.0% power production 3 7 24.9% 4 9 22.0% 11 20.2% 6 13 18.9% 15 18.0% 8 17 17.3% 19 16.7% 10 21 16.3% 23 15.9% 12 25 15.6% 28 15.2% Wind Load Case Wind Gust Type Event DLC1.5 12 m/s EOG1 Grid Loss DLC1.6 25 m/s EOG50 Active Safety Syst. DLC2.2 constant Pitch Runaway EWEC 2007

3.3 Fatigue DLCs Control Variables Load Variables EWEC 2007

3.4 Extreme DLCs Control Variables Load Variables EWEC 2007

Load Assumptions for the Design of electro mechanic Pitch Systems Simulation Model Design Load Cases (DLCs) Data Postprocessing 4.1 Design Driver 4.2 Loads for Drive Motor 4.3 Loads for Gearbox 4.4 Loads for Blade Bearing Mesh Conclusion and Outlook Source: ENERCON EWEC 2007

4.1 Design Driver Pitch System Component Type of Load Drive Motor MPDA - Pitch Actuator Torque αP* - Speed of Pitch Actuator RMS(MPDA ) - Thermal Loading Gearbox LDD of MM - Mesh Torque (Load Duration Distribution) Mesh of Blade Bearing Distribution of MM vs. αP (Pitch Angle Duration Distribution) EWEC 2007

4.2.1 Loads for Drive Motor Operation States of Drive Motor, Confirmation of global Wind Turbine Simulation EWEC 2007

4.2.2 Thermal Loads for Drive Motor Standard Deviation (RMS) of pitch actuator torque for thermal impact Efficiency of gear box and has to be considered Normal bearing friction Increased bearing friction (+50%) EWEC 2007

4.3 Loads for Gearbox Load Duration Distribution counting for Mesh Torque M_M Influence of Blade Bearing Friction Level comparatively low M_M > 0 M_M < 0 EWEC 2007

4.4 Loads for Blade Bearing Mesh Load Duration Distribution counting for Mesh Torque M_M Pitch Angle Duration Distribution counting EWEC 2007

Load Assumptions for the Design of electro mechanic Pitch Systems Simulation Model Design Load Cases (DLCs) Data Postprocessing Conclusion and Outlook Source: ENERCON EWEC 2007

5 Conclusion and Outlook Aerodynamic pitch Moment MZB is not sufficient for the design of pitch systems drive train Pitch Actuator Torque is inevitable Blade bearing friction model included in the global simulation model Integration of drive control unit into the global simulation model, e.g. limitations in speed and torque of pitch drive actuator 80% damage within first 20°- 25° of blade bearing mesh Measurements on drive trains of pitch systems to validate MM-assumption EWEC 2007

Keep in Contact Andreas Manjock Germanischer Lloyd Industrial Services Andreas.Manjock@gl-group.com, www.gl-group.com/glwind EWEC 2007