Concepts and Research Vectors on Energy Management Technology / Systems

Johann W. Kolar & Arda Tüysüz

Swiss Federal Institute of Technology (ETH) ZurichPower Electronic Systems Laboratory

www.pes.ee.ethz.ch

► General Energy Management System (1)

Short Term Storage

Long Term Storage

Wide Application

Area

www.refu-energy.de

■ Hybrid Power Solutions ─ Combination of Motors / Actuators and El. Storage

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► General Energy Management System (2)

■ Hybrid Power Solutions ─ Combination of Motors / Actuators and El. Storage

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www.refu-energy.de

► Hybrid Power Solutions ─ Generalwww.refu-energy.de

■ Key Technologies System Topology / Storage / Converters / Control

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► Example #1http://www.refu-drive.de/en/branchen/hafentechnik.html

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► Example #2http://www.refu-drive.de/en/branchen/bergbau.html

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► Example #3http://www.refu-drive.de/en/branchen/baustellen.html

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► Example #4http://www.refu-drive.de/en/branchen/kommunalfahrzeuge.html

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► Example #5http://www.refu-drive.de/en/branchen/landwirtschaft.html

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■ General Characteristics in Order to Allow an Improvement by Energy Management• Large Peak to Average Load Ratio (Heavy Power Fluctuation)• Short and Long Term Power Fluctuations• Actuators (Machines) with Low Efficiency in Certain Operating Regions• Regeneration of Power Occurs• Connection to Relatively Weak Grid Only Able to Supply Average (Low) Power • Storage Allows for for Peak Load Buffering AND Regeneration• Storage Used in Addition for Renewable System Integration

■ Key Areas Which Could Give NABTESCO a “Competitive Edge”• Batteries (Li-Ion, Lead Acid, Redox-Flow, etc.) and Supercapacitors• Battery State-of-Charge, Monitoring, Aging (will Anyway be an Important Competence in Future)• Modular Power Electronics Converters for EMS Realization• Communication Between System Components (Software, ICT) • Optimal Design of Hybrid Systems

■ What is the Targeted “Unique Selling Proposition” of NABTESCO in EMS ?

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► Summary / Questions

► Potential Research Topics

■ Prerequisite of Research - Identify Target Application (Load Profiles, Today´s Solution etc.)• Hybrid Excavator • Hybrid Truck / Vehicle • Hybrid Crane• Weak Grid Peak Power Buffering / Stabilization (incl. Smart Wires for Power Transmission Steering)• etc.

■ System Level• Optimal EMS Topology (Given Actuators/Motors/Loads – Placement of Conv. and Storages)• Design and Control for Opt. Matching of Load Profile and Storage Capacity / Charge / Discharge Cycle • Overall Control Stability of the Managed System • EMS Design Platform (e.g. Opt. Eff. Operation for Given Load Profile, Minimal LCC, etc.)

■ Component Level• Power Electronics Building Blocks for Flexible Converter Realization • Modular Converter System (Battery Charger, Isolated/Non-Isolated DC/DC Converter, Inverter)

• Battery Technologies (Li-Ion, Redox-Flow, Environmentally Friendly Battery Technologies)• Internal SOC Management of Batteries (Balancing of Series Connected Battery Cells acc. to SOC etc.)• Effect of Pulsed Operation on Aging• Monitoring of Batteries (Aging - Impedance Spectroscopy, etc.)

• Hybrid Actuators (Hydraulic + Electric, Pneumatic + Electric)• Working “Fluid” Storage (Hydraulic Storage, Pneumatic Storage)

• Integration of Renewable Energy Sources

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► Hybrid Actuators – Combining Advantages

• Hydraulic + Electric• Pneumatic + Electric

• Controllability / Accuracy

• Reliability / Robustness• Lifetime• Environmental Impact (Leakage)• Installation Cost / Total Cost of Ownership

• Integration of Energy Storage• Mechanical Buffer (Hyd. Accumulator)• Electrical Buffer (Supercaps)

■ Key Competences Electromagnetics/ Power Electronics / Control / Thermal / Mechanical

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► Hybrid Actuators – Design/Application Example #1

■ Key Competences Electromagnetics/ Power Electronics / Control / Thermal / Mechanical

• Off-Highway Working Vehicles

• Integrated Electro-Hydraulic Energy Converter (IEHEC)• Hydraulic Pump• Integrated PMSM

• Working Fluid Cooling• Power Electronic Converter

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► Hybrid Actuators – Design/Application Example #2

■ Key Competences Electromagnetics/ Power Electronics / Control / Thermal / Mechanical

• Robotic Exoskeleton

• Optimal Torque/Force Distribution • Electrical and Pneumatic Actuators • Trajectory-Based Optimal Control• System Identification / Robust Control

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► Energy Storage – Mechanical or Chemical ?

• Flywheels vs Electrochemical Batteries • 3ph. DC/AC vs DC/DC Converters

• Energy / Power Density• Robustness / Reliability• Cost (of Ownership)

• Operating Environment

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► Energy Storage – Mechanical or Chemical ?

• Ultra-High-Speed Flywheels vs. Electrochemical Batteries

• 3.5 Wh/kg vs. 70 Wh/kg

• Lifetime (Nr. of Cycles)• Environmental Limits

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Thank You !