New Frontiers of Brushless PM Motor Technology

Transcription

1 New Frontiers of Brushless PM Motor Technology Dan M. Ionel, Ph.D., IEEE Fellow CWIEME Berlin, May 11, 2016 Introduction February,

2 Dr. Dan M. Ionel Dan M. Ionel is Professor of Electrical Engineering and L. Stanley Pigman Chair in Power at University of Kentucky in Lexington, KY. Previously, he held dual appointments in industry, as Chief Engineer with Regal Beloit Corp and before as Chief Scientist with Vestas Wind Turbines, and in academia, as Visiting and Research Professor with University of Wisconsin and Marquette University in Milwaukee, WI. Dr. Ionel has more than 25 years of engineering experience and has designed electric machines and drives with power ratings between and 10,000hp. He holds more than 30 patents and has published more than 100 journal and conference papers, including two winners of IEEE best paper awards. Dr. Ionel is an IEEE Fellow, the Chair of the IEEE Power and Energy Society Electric Motor Subcommittee, and the General Chair of the 2017 anniversary edition of the IEEE IEMDC Conference. New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May

3 and PEIK at University of Kentucky (UK) UK enjoys a longstanding tradition in electric machines and drives Early developments on linear and PM motors, and vector control Many learned machines using the Nasar and Boldea classic books PEIK - Power and Energy Institute of Kentucky, launched with large DOE grant in 2010 Core faculty in electric power engineering and many others in related fields Endowment established and inaugural L. Stanley Pigman Chair started in 2015 On-going research on electric machines and drives, power electronics and systems, renewable and alternative energy technologies and other laboratories Motor Design Ltd. and ANSYS Inc. strategic partnerships. New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May

4 Motor Design Ltd. and Center for Applied Energy Research Motor Design Ltd. (MDL) Founded in 1998 Developers of the Motor-CAD & Motor-LAB software Engineering and R&D projects for companies and EU programs Strategic partner of ANSYS. Center for Applied Energy Research (CAER) Established in 1975 One of University of Kentucky s largest, stand-alone, multidisciplinary research centers with more than 100 staff Fiber Development with the largest solution spinning line found in an academic setting in North America Renowned research program on nano carbon composites. New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May

5 Outline 1. Introduction 2. How far can we reach with existent materials? Record-braking motor Formula E racing cars Design considerations for industrial applications Large scale optimization and innovation Complex duty cycles multi-physics analysis, including thermal 3. How far will we be able to reach with new materials? Nanocarbon wires and windings Material characteristics and manufacturing issues Electric motor concepts solar planes and cars US DOE research program Next Generation Electric Machines. 4. Conclusions. New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May

6 AIM Motor Introduction FIA Formula E started in and 5 Identic cars: Spark-Renault SRT_01E 2 Powertrain and electronics: McLaren Electronics 3 Gearbox: Hewland 4 Battery 200kW: Williams Advanced Engineering 6 Tyres: Michelin. Source: Typical racing car driving cycle for one lap - LeMans New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May

7 Comparative Performance Motor Type Torque (Nm) Mass (kg) TRW (Nm/kg) Toyota Prius (2004) Interior PM Nissan Leaf Interior PM Tesla S Induction YASA 400 Axial PM AIM Spoke PM Note: Values listed are for peak torque and active material mass. New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May

8 Variable Speed Motor Drives Drive Cycles Shaft torque, pu Design considerations Constant torque Fan or pump load curve Duty / driving cycle, incl. transients Analysis of each design requires analysis for multiple operating conditions speed, pu efficiency map 2 Hp 4 Hp 6 Hp 8 Hp 10 Hp Fan load New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May

9 Multi-objective Optimization Example Minimize cost and minimize losses (i.e. maximize efficiency) Impose constraints Quantify the effects on other performance indices Thousands of design candidates (variations) may have to be analyzed Collection of best compromise designs Definition of a Pareto front: improvement in one objective can only be achieved through a deterioration in another objective, e.g. cost vs. efficiency tradeoffs New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May

10 Example Comparative Study SynRel and PMSynRel Systematic optimization study with 10,000 candidate designs ultra-fast electromagnetic FEA differential evolution (DE) Typical rating 10hp 1,800rpm Induction motor stator core and winding pattern Independent variables for rotor geometry (8 or 9) and torque angle Comprehensive performance evaluation Two objectives: max power factor and min. badness One constraint: torque ripple smaller than 20%. New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May

11 Synchronous Reluctance (SynRel) New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May

12 PM Assisted Synchronous Reluctance (PMSynRel) New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May

13 Coupled Electromagnetic and Thermal Analysis PM machine specific characteristics Variation of PM characteristics with temperature Torque per amp (torque constant) changes Risk of demagnetization, especially in PM hot spots Variation of winding conductor characteristics with temperature. Model Losses Temperature New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May

14 Coupled Electromagnetic and Thermal Analysis Motor-CAD Electromagnetics Ultra-fast 2D FEA in the abc reference frame Seconds on a state of the art PC workstation Analytical calculations for end effects Thermal and air-flow Equivalent 3D networks Calculation time one order of magnitude shorter than for electromagnetics Coupling methods Serial, typ. 6 iterations for each of Emag and thermal Weak, typ. only 2 iterations for Emag and 6-10 for thermal Cutting edge Design for complex duty cycles Large-scale optimization studies. New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May

15 Fast Duty Cycle Analysis Motor-LAB Maxwell Motor-CAD Therm New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May

16 Multi-objective Design Optimization New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May

17 AIM Motor Factsheet E-motor for racing applications Peak torque = 110Nm Cont. torque = 70Nm Max speed = 12,000rpm Power = 73/60 kw Max. current = 325Arms Field oriented control Rare-earth magnets Non-oriented thin gage silicon steel Liquid and air cooled Active materials mass = 9kg Manufactured by Equipmake Electromagnetic & Thermal design by Motor Design Ltd. New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May

18 AIM Motor Stator and Rotor New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May

19 AIM Motor Modeling New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May

20 Magnetic Field and Copper Losses Pac/Pdc 30 Flux-lines and flux-density distribution on (peak) load Frequency [Hz] AC losses in the stator winding New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May

21 Core Losses Most core losses located in the stator Rotor surface can also have high loss density Highest loss concentration occurs in stator teeth and winding. Pt [W/Kg] Core losses on (peak) load 0 New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May

22 Magnet Losses - Sources PMs may be electrically conductive Conductivity increases 6%-10% for 100C temperature rise Higher PM losses in surface SPM than interior IPM Surface BPM may require a retainer sleeve with additional losses Retainers of glass fibre or carbon fibre Eddy-current induced by: Space MMF harmonics Permeance variation Time current harmonics Induced eddy-currents create PM losses Magnet losses mitigation methods: Integer or fractional slots/pole Segmentation. Material Resistivity (ohm*m) Copper 1.7 x 10-8 Aluminum 2.8 x 10-8 Steel 10 x 10-8 SmCo 1-5 Alloys 50 x 10-8 SmCo 2-17 Alloys 90 x 10-8 NdFeB sintered 160 x 10-8 NdFeB bonded 14,000 x 10-8 Ferrite 10 5 New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May

23 Magnet Losses - Mitigation Distribution of specific on-load PM losses m = transversal segments n = axial segments Effect of segmentation on the magnet losses Psegmented L P ml n monolithic New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May

24 Efficiency maps (MTPA) I max = 325Arms, T wdg = 160C 0, T mag = 120C 0 New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May

25 Duty Cycle Loss model of the typical racing car driving cycle for one lap New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May

26 Transient Thermal Analysis Results for 20 laps drive cycle New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May

27 Experimental Data Measured and calculated torque (q-axis current excitation, PMs at 40C 0 ) Measured total loss vs. current and speed at 40C 0 New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May

28 Carbon Nanotubes (CNT) Individual carbon nanotubes (CNT) can have a conductivity up to 100 MS/m and very low mass density Conductivity substantially decreases when individual CNTs are assembled to form macroscopic conductors Conductivity may be enhanced by plating nanotubes with copper (Cu). Conductivity (MS/m) Density (kg/m3) Temp Coeff of Resistance (/K) Thermal Conductivity (W/mK) Specific Heat Capacity (J/kgK) Copper Aluminum CNT Wire # CNT Wire # New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May

29 Fiber Development at University of Kentucky (UK) Part of the large Center for Applied Energy Research (CAER). Largest solution spinning line found in an academic setting in North America. New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May

30 Cu-plated Aligned MWCNT Wires Bore dispersion MWCNTs Cu-plated MWCNTs Alignment by drawing Cu-MWCNT conductor core wire New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May

31 Coreless Multi-Disc Axial Flux PM machine Systematic study on a suitable benchmark Coreless topology windings account for most active weight and losses Conventional counterpart originally developed at University of Bath for the European HELINET solar airplane Multiple stator modules and rotor discs Stator with coils and a light supporting structure PM rotor. New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May

32 Example Design Studies Performance improvement achieved by replacing copper coils with carbon nanotube (CNT) windings. Machines with CNT windings maybe larger in size and lighter. AC supplementary losses in NCT windings are negligible. Further improvements possible due to better heath transfer. New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May

33 US DOE Research Program for NCT Wires and Machines High performance conductors to minimize losses in the stator windings To be demonstrated on a 28 AWG NCT round wire with 1 m length Minimum of 33% reduction in I2R losses per unit weight or volume over a 28 AWG round copper or Al wire at C Use the new wire to demonstrate a 1 hp single phase induction motor, including windings with electric insulation. Source: US DOE-FOA , Next Generation Electric Machines: Enabling Technologies, Photo courtesy of Regal Beloit Corp. New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May

34 Conclusion Things that we can do today Example ultra-high torque density (12Nm/kg) AIM motor developed for Formula E racing cars Innovate with existent materials Automated design optimization Motor performance under duty / driving cycles simulated using electromagnetic and thermal coupled analysis Things that we maybe able to do in the future New materials such as nanocarbon tubes and wires It may take some time to deploy the new technology in conventional industrial applications First in line to benefit may be high-tech applications, such as those for aerospace. New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May

35 References Wang, Yi, Ionel, D. M., Staton, D. A., Ultrafast Steady-State Multiphysics Model for PM and Synchronous Reluctance Machines, IEEE Transactions on Industry Applications, Vol. 51, No. 5, Sep/Oct 2015, pp Zhang Peng, Sizov, G. Y., Ionel, D. M., Demerdash, N.A.O., Establishing the Relative Merits of Interior and Spoke- Type Permanent-Magnet Machines with Ferrite or NdFeB through Systematic Design Optimization, IEEE Transactions on Industry Applications, Vol. 51, No. 4, Jul/Aug 2015, pp Wrobel, R., Simpson, N., Mellor, P., Goss, J., Staton, D. A., Design of a Brushless PM Starter-Generator for Low-Cost Manufacture and a High-Aspect-Ratio Mechanical Space Envelope, Proceedings IEEE ECCE 2015 Congress, Montreal, Canada, Sept. 2015, pp A. Fatemi, N. Demerdash, T. Nehl, D.M. Ionel, "Large-scale Design Optimization of PM Machines Over a Target Operating Cycle," in press, IEEE Transactions on Industry Applications, Early Access DOI: /TIA Yi Wang, D. M. Ionel, M. Jiang, S. J. Stretz, Establishing the Relative Merits of Synchronous Reluctance and PM Assisted Technology Through Systematic Design Optimization, in press, IEEE Transactions on Industry Applications, Early Access DOI: /TIA Popescu, M., Foley, I., Staton, D. A., Goss, J. E., Multi-physics Analysis of a High Torque Density Motor for Electric Cars, Proceedings IEEE ECCE 2015 Congress, Montreal, Canada, Sept. 2015, pp Fatemi A., Ionel D. M., Demerdash N.A.O., Popescu, M., Design Optimization of Spoke-Type PM Motors for Formula E Racing Cars, accepted for publication in Proc. of ECCE 2016 Vandana Rallabandi, Narges Taran, D. M. Ionel and J. F. Eastham, On the Feasibility of Carbon Nanotube Windings for Electrical Machines: Case Study for a Coreless Axial Flux Motor, accepted for publication in Proc. of ECCE New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May

36 University of Kentucky Solar Car New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May

37 Consortium and Acknowledgments The - SEMPEED Consortium was recently established to further the art of electric machine design Two academic sites at University of Kentucky and Marquette University and one partner software company, Motor Design Ltd (MDL) Four inaugural members: Grundfos, Kollmorgen, MTS, and Regal Beloit Inspired by the legacy of the SPEED Consortium The continued support of ANSYS for our academic research is gratefully acknowledged. New Frontiers of Brushless PM Motor Technology CWIEME Berlin, May