MODEL PREDICTIVE CONTROL OF WIND ENERGY CONVERSION SYSTEMS
Dr. Venkata Yaramasu Assistant Professor of Electrical Engineering School of Informatics, Computing, and Cyber Systems (SICCS) Northern Arizona University
Contact Info Office: Room 113, Building#90 Photo Courtesy: Phone: +1-928-523-6092 Enercon E-126 (6 MW) E-Mail: [email protected]
Puerto Varas, Chile Photo Courtesy: AMSC SeaTitan (10 MW) Model Predictive
Control (MPC) is Like
Playing Chess!!
Prediction
Optimization
Receding Horizon
Strategy
By Karophyr at English Wikipedia - Transferred from en.wikipedia to Commons., CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=2160498
MPC of WECS 2 https://openi.nlm.nih.gov/index.php MPC versus Proportional-Integrate-Derivative (PID) control
MPC of WECS 3 Contents
High-Power WECS
Configurations of Commercial WECS
Model Predictive Control (MPC)
MPC of PMSG WECS
MPC of SCIG WECS
MPC of DFIG WECS
Concluding Remarks
MPC of WECS 4 Reference
V. Yaramasu, and B. Wu, “Model Predictive Control of Wind Energy Conversion Systems,” Wiley–IEEE Press, IEEE Press Series on Power Engineering, 459 pages, 3 parts with 12 chapters, February, 2017, ISBN: 9781118988589.
MPC of WECS 5 High-Power WECS Wind Kinetic Energy to Electric Energy Conversion
(Photo courtesy: Siemens)
Kinetic Energy Mechanical Electrical in Wind Energy Energy
MPC of WECS 6 High-Power WECS Wind Turbine Construction
Photo courtesy: Bosch Rexroth AG
Mechanical Components (Tower, Blades, Rotor Hub, Pitch Drives, Yaw Drives, Nacelle, Gearbox, Brakes)
Electrical Components (Generator, Converter, Transformer, Cables)
Control Systems (Mechanical and Electrical)
MPC of WECS 7 High-Power WECS Trends in High-Power WTs
Wind turbines above 1 MW dominate the market
15-20 MW turbines will hit market by 2020
Large wind turbines: AMSC SeaTitan (10 MW), Vestas V164 (7MW) ,
Enercon E-126 (6MW), RePower 6M (6MW), Multibrid M5000 (5MW)
MPC of WECS 8 High-Power WECS Trends in High-Power WTs
Largest PMSG wind turbine Wind turbine : 7MW Manufacturer: Vestas - 443 feet above the waves - Rotor blades measuring a full 262 feet - Dedicated to offshore placement V164 – 7.0MW - First prototype built in 2012 - Full production in 2015 http://www.physorg.com/news/2011-04-vestas-megawatt-offshore-turbine.html
MPC of WECS 9 High-Power WECS Trends in High-Power WTs
MPC of WECS 10 High-Power WECS Trends in High-Power WTs
MPC of WECS 11 High-Power WECS Offshore Wind Turbines/Farms
Offshore Wind Farm
Substation Denmark Horns Rev Wind Farm Power rating : 160MW (2.0MW x 80) Manufacturer: Vestas Location : Denmark Commissioned: 2002 Transmission: AC 15kV, 19km (offshore) + 33km (onshore)
MPC of WECS 12 Configurations of Commercial WECS
Type 1: Fixed Speed (±1 %) SCIG WECS
Simple Technology
Low Cost & Low Maintenance (Photo courtesy: Vestas) X Low wind energy conversion efficiency V82, 1.65 MW X High mechanical stress on turbine components Technology Status: X Requires soft starter and PF compensator Outdated
MPC of WECS 13 Configurations of Commercial WECS
Type 2: Semi Variable-Speed (±10 %) WRIG WECS
Relatively higher wind energy conversion efficiency
Relatively lower stress on turbine components
(Photo courtesy: Suzlon) X Requires maintenance due to slip-rings S88, 2.1 MW X Power losses due to rotor resistor Technology Status: X Requires soft starter and PF compensator Outdated
MPC of WECS 14 Configurations of Commercial WECS
Type 3: Semi Variable-Speed (±30 %) DFIG WECS
Relatively higher wind energy conversion efficiency
Relatively lower stress on turbine components (Photo courtesy: RePower) Eliminates soft starter and PF compensator RE6M, 6.0 MW
X Higher cost and complexity Technology Status: Highly Mature X Requires maintenance due to slip-rings > 50 % Share
MPC of WECS 15 Configurations of Commercial WECS
Type 4: Full Variable-Speed (0-100 %) IG/SG WECS
(Photo courtesy: Enercon) Highest wind energy conversion efficiency E126, 6.0 MW
Excellent grid code compliance, Optional gearbox Technology Status: Mature/Emerging X Higher cost, power losses and complexity 2nd Highest Share
MPC of WECS 16 Configurations of Commercial WECS
BTB
2L VSR + DC-Link + 2L-VSI 3L VSR + DC-Link + 3L-VSI LV MV
Diode Rectifier + 2L Boost + 2L VSC PGS
MPC of WECS 17 Configurations of Commercial WECS
BTB
2L VSR + DC-Link + 2L-VSI 3L VSR + DC-Link + 3L-VSI LV MV
Diode Rectifier + 2L Boost + 2L VSC Diode Rectifier + 3L Boost + 3L VSC WESNet Research Program PGS Diode Rectifier + 4L Boost + 4L VSC MPC of WECS 18 Configurations of Commercial WECS
Type 5: Full Variable-Speed (0-100 %) SG WECS
Highest wind energy conversion efficiency
No power converter and associated losses (Photo courtesy: DeWind) Step-up transformer is optional D82, 2.2 MW
X Complicated design due to speed/torque converter Technology Status: Old Concept X Requires maintenance due to slip-rings Limited Share
MPC of WECS 19 Configurations of Commercial WECS
Top 10 Wind Turbine Manufacturers and Their Priority Technology
Source: Global Wind Energy Council (GWEC)
7 Manufacturers use Type-3 technology, 100+ turbine models 6 Manufacturers use Type-4 technology Future market belongs to Type-4 technology
MPC of WECS 20 Model Predictive Control A Big Picture of WECS Control
Level VI: Slow Control
Level I: Fast Control
Efficient Control of Power Converter Leads to Stable Power System Operation
Operations: MPPT, Grid Integration, Reactive Power Control, Fault-Ride Through Operation, etc.
MPC of WECS 21 Model Predictive Control Overview of Digital Control Techniques
MPC of WECS 22 Model Predictive Control Linear Control Vs. MPC
Concept of Linear Control
Uses cascaded linear regulators and a modulation stage
Concept of Model Predictive Control
Uses predictive model and cost function
MPC of WECS 23 Model Predictive Control Main Features of MPC
MPC of WECS 24 Model Predictive Control Control Objectives for WECS
MPC of WECS 25 Predictive Current Control of 2L-VSC-Based PMSG WECS
Design Procedure:
1. Measurement and Synthesis
of Feedback Signals
DC-link voltage
PMSG currents
Mechanical speed and
position
Wind speed
MPC of WECS 26 Predictive Current Control of 2L-VSC-Based PMSG WECS
Design Procedure:
2. Calculation of Reference
Generator Currents
∗ MPPT control ( )
∗ PMSG speed control ( )
Zero d-axis control (ZDC)
∗ ∗ ( and )
MPC of WECS 27 Predictive Current Control of 2L-VSC-Based PMSG WECS
Design Procedure:
3. Extrapolation of Reference
Generator Currents
MPC of WECS 28 Predictive Current Control of 2L-VSC-Based PMSG WECS
Design Procedure:
4. Prediction of Future
Behavior of PMSG Currents
MPC of WECS 29 Predictive Current Control of 2L-VSC-Based PMSG WECS
Design Procedure:
4. Prediction of Future Behavior of PMSG Currents
Discrete-time model of PMSG Currents:
8 possible switching states leads to 8 different Discrete-time matrices: future values of PMSG currents.
MPC of WECS 30 Predictive Current Control of 2L-VSC-Based PMSG WECS
Design Procedure:
5. Generation of Optimal
Switching Signal Through
Cost Function Minimization
MPC of WECS 31 Predictive Current Control of 2L-VSC-Based PMSG WECS
Design Procedure:
5. Generation of Optimal Switching Signal Through Cost
Function Minimization
Switching state (among the possible 8)
which minimizes the cost function is
selected and applied to the converter during
Cost Function: next sampling interval.
MPC of WECS 32 Predictive Current Control of 2L-VSC-Based PMSG WECS
Flowchart of the PCC algorithm for: (a) PMSG-side 2L-VSR and (b) grid-side 2L-VSI.
MPC of WECS 33 Case study with 3.0 MW, 690 V, 9.75 Hz, direct-drive PMSG
1. Define switching states
2. Predict converter output voltages based on all possible switching states
3. Predict PMSG currents based on predicted converter output voltages
4. Calculate cost function values
5. Select optimal switching state corresponding to the minimum cost function value
6. Apply optimal switching state to the converter during next sampling interval.
MPC of WECS 34 Steady-state waveforms with the PCC scheme for 2L-VSC-based SPMSG WECS
MPC of WECS 35 Predictive Current Control of Grid-Connected 2L-VSI
Design Procedure: 1. Measurement and Synthesis of Feedback Signals 2. Calculation of Reference Grid Currents 3. Extrapolation of Reference Grid Currents 4. Prediction of Future Behavior of Grid Currents 5. Generation of Optimal Switching Signal Through Cost Function Minimization
MPC of WECS 36 Predictive Current Control of Grid-Connected 2L-VSI
Predictive Model:
Cost Function:
MPC of WECS 37 Predictive Current Control of 3L-VSC-Based PMSG WECS
Design Procedure:
1. Measurement and Synthesis of Feedback Signals 2. Calculation of Reference Generator Currents 3. Extrapolation of Reference Generator Currents 4. Prediction of Future Behavior of PMSG Currents and DC Capacitors Voltage 5. Generation of Optimal Switching Signal Through Cost Function Minimization
MPC of WECS 38 Predictive Current Control of 3L-VSC-Based PMSG WECS
Predictive Model:
Cost Function:
MPC of WECS 39 Predictive Current Control of 3L-VSC-Based PMSG WECS
Flowchart of the PCC algorithm for: (a) PMSG-side 3L-VSR and (b) grid-side 3L-VSI.
MPC of WECS 40 Simulated waveforms with the PCC scheme for IPMSG WECS during start-up
MPC of WECS 41 Simulated waveforms with the PCC scheme for IPMSG WECS during start-up
MPC of WECS 42 Predictive Current Control of 2L-Boost Converter-Based PMSG WECS
Design Procedure:
1. Measurement and Synthesis of Feedback Signals 2. Calculation of Reference Inductor Current 3. Extrapolation of Reference Inductor Current 4. Prediction of Future Behavior of Inductor Current 5. Generation of Optimal Switching Signal Through Cost Function Minimization
MPC of WECS 43 Predictive Current Control of 2L-Boost Converter-Based PMSG WECS
Predictive Model:
Cost Function:
MPC of WECS 44 Predictive Current Control of 3L-Boost Converter-Based PMSG WECS
Design Procedure:
1. Measurement and Synthesis of Feedback Signals 2. Calculation of Reference Inductor Current 3. Extrapolation of Reference Inductor Current 4. Prediction of Future Behavior of Inductor Current and DC Capacitors Voltage 5. Generation of Optimal Switching Signal Through Cost Function Minimization
MPC of WECS 45 Predictive Current Control of 3L-Boost Converter-Based PMSG WECS
Predictive Model:
Cost Function:
MPC of WECS 46 Steady-state waveforms for a 3L boost converter-based PMSG WECS
MPC of WECS 47 3L boost converter-based PMSG WECS during step-change in wind speed
MPC of WECS 48 Predictive Current Control of 2L-VSC-Based SCIG WECS
Design Procedure:
1. Measurement and Synthesis of Feedback Signals 2. Calculation of Reference Generator Currents 3. Extrapolation of Reference Generator Currents 4. Prediction of Future Behavior of SCIG Currents 5. Generation of Optimal Switching Signal Through Cost Function Minimization
MPC of WECS 49 Predictive Current Control of 2L-VSC-Based SCIG WECS
Predictive Model:
Cost Function:
MPC of WECS 50 Steady-state waveforms with PCC scheme for 2L-VSC-based SCIG WECS
MPC of WECS 51 Predictive Torque Control of 3L-VSC-Based SCIG WECS
Design Procedure:
1. Measurement and Synthesis of Feedback Signals 2. Calculation of Reference Generator Torque and Flux 3. Extrapolation of Reference Generator Torque and Flux 4. Prediction of Future Behavior of SCIG Torque and Flux 5. Generation of Optimal Switching Signal Through Cost Function Minimization
MPC of WECS 52 Predictive Torque Control of 3L-VSC-Based SCIG WECS
Predictive Model:
MPC of WECS 53 Predictive Torque Control of 3L-VSC-Based SCIG WECS
Cost Function:
MPC of WECS 54 PTC scheme for 2L-VSC-based SCIG WECS during step-change in wind speed
MPC of WECS 55 Predictive Current Control of 2L-VSC-Based DFIG WECS
Design Procedure:
1. Measurement and Synthesis of Feedback Signals 2. Calculation of Reference Generator Currents 3. Extrapolation of Reference Generator Currents 4. Prediction of Future Behavior of SCIG Currents 5. Generation of Optimal Switching Signal Through Cost Function Minimization
MPC of WECS 56 Predictive Current Control of 2L-VSC-Based DFIG WECS
Predictive Model:
Cost Function:
MPC of WECS 57 DFIG WECS during transition from subsynchronous to supersynchronous mode of operation
MPC of WECS 58 Concluding Remarks
Model predictive control is a simple, intuitive, and promising digital control tool for energy systems such as: Wind energy conversion systems Photovoltaic energy systems Energy storage systems Electric motor drives Electric vehicles Power quality conditioners High voltage direct current (HVDC) systems
MPC of WECS 59