The IEEE 1812 Trial-Use Guide for Testing PM Machines Virtual Testing Developments

The IEEE 1812 Trial-Use Guide for Testing PM Machines Virtual Testing Developments Dan M. Ionel, Ph.D., IEEE Fellow dan.ionel@uky.edu CWIEME Berlin, May 10, 2016 Introduction February, 2016 1

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 0.002 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. dan.ionel@uky.edu PM Machine Testing CWIEME Berlin, May 2016 2

and PEIK at University of Kentucky 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. PM Machine Testing CWIEME Berlin, May 2016 3

Outline IEEE 1812 IEEE Trial-Use Guide for Testing Permanent Magnet Machines Status review, based on WG reports and published Guide WG Past Chair, Dr. H. Karmaker; MSC Chair, Dr. Dan M. Ionel Special thanks to Dr. Karmaker for his contributions to the first section of this presentation Developments for equivalent circuit parameters and losses PE converter controls DQ inductances Separation of losses Related developments - Virtual testing High fidelity models and reduced order models Hardware in the Loop (HIL) and Real Time Digital Simulation (RTDS). PM Machine Testing CWIEME Berlin, May 2016 4

IEEE 1812 Purpose There are many differences in testing the performance characteristics of PM and non-pm machines In PM machines, excitation cannot be turned off and controlled similar to electrically excited machines There is no known guide or standard for testing PM machines. PM Machine Testing CWIEME Berlin, May 2016 6

IEEE 1812 Scope (1/2) The scope of the Guide as approved by the IEEE Standards Board is as follows: The guide contains instructions for conducting tests to determine the performance characteristics and parameters of permanent magnet (PM) machines The tests may be applied to both motors and generators This guide covers only general test methods characteristic to PM machines The test methods should be applicable to the PM machines of different sizes and configurations continued... PM Machine Testing CWIEME Berlin, May 2016 7

IEEE 1812 Scope (2/2) The scope of the Guide as approved by the IEEE Standards Board is as follows: continued The guide shall not cover all possible tests or tests of a research nature The tests covered by other applicable standards are not covered in this guide This trial-use guide shall not be interpreted as requiring any specific test in a given transaction or implying any guarantee as to the specific performance indices or operating conditions. PM Machine Testing CWIEME Berlin, May 2016 8

Working Group (WG) for IEEE 1812 A new IEEE Power and Energy Society (PES) WG was formed by the Motor Subcommittee (MSC) of the Electric Machinery Technical Committee (EMC) in July 2009 Original WG Chair, now WG Past Chair, Dr. Haran Karmaker Current MSC Chair, Dr. Dan M. Ionel The proposed project was approved for a trial-use guide in December 2009 by IEEE Standards Board with the expiration date of December 31, 2013 The IEEE Industry Applications Society started to co-sponsors the project in May 2011 The IEEE 1812 Trial-Use Guide was approved in Dec 2014 The final WG comprised 23 members, 16 being from industry. PM Machine Testing CWIEME Berlin, May 2016 9

IEEE Working Group PM Machine Testing CWIEME Berlin, May 2016 10

IEEE 1812 Overview WG 1812 followed the structure of the most current edition of IEEE 115-2009 IEEE Guide for Test Procedures for Synchronous Machines: Part I Acceptance and Performance Testing ; Part II Test Procedures and Parameter Determination for Dynamic Analysis to prepare the new draft for the guide Following the IEEE 115 structure, IEEE 1812 was drafted for Part I Test Procedures Part II Machine Characteristics According to the IEEE style guide, the first two clauses are: Clause 1 Overview Clause 2 Normative References The guide consists of a total of six (6) clauses. PM Machine Testing CWIEME Berlin, May 2016 11

IEEE 1812 Overview (Contd.) Clause 3 - Condition and integrity tests, i.e. resistance measurement, phase sequence, insulation resistance, dielectric and partial discharge, polarity for magnets, shaft and bearing currents, over-speed tests, resistance to demagnetization, acoustic noise, vibration Clause 4 - Steady-state tests, i.e. open-circuit (back emf, losses, and cogging torque), short-circuit, load, thermal performance Clause 5 - Transient tests, i.e. retardation (or coast-down), sudden short-circuit (three phase and two phase) Clause 6 - Machine operating characteristics, i.e. stator voltage waveform, losses and efficiency, thermal capability, torque ripple. PM Machine Testing CWIEME Berlin, May 2016 12

Example Dynamic Cogging Torque Measurement PM Machine Testing CWIEME Berlin, May 2016 13

Example Static Cogging Torque Measurement PM Machine Testing CWIEME Berlin, May 2016 14

Example Torque Ripple Measurement at Load PM Machine Testing CWIEME Berlin, May 2016 15

Example Typical Torque Ripple Waveform PM Machine Testing CWIEME Berlin, May 2016 16

Example Short Circuit Testing PM Machine Testing CWIEME Berlin, May 2016 17

Example Back-to-back Load Test PM Machine Testing CWIEME Berlin, May 2016 18

Example Thermal Characteristics of PM Materials PM Machine Testing CWIEME Berlin, May 2016 19

Example Open Circuit Core Loss Characteristic PM Machine Testing CWIEME Berlin, May 2016 20

Example Friction & Windage Loss Characteristic PM Machine Testing CWIEME Berlin, May 2016 21

Example - Loss Separation Friction and windage loss The PM rotor is replaced with a non-magnetized equivalent rotor (rotor with PMs yet to be magnetized This test relies on the knowledge of the combined moment of inertia of the test machine and the drive motor The friction and windage loss is determined as a function of speed, if inertia and rate of change of speed are known. PM Machine Testing CWIEME Berlin, May 2016 22

Example Performance Curves of PM Generator PM Machine Testing CWIEME Berlin, May 2016 23

IEEE 1812 Current Status The standard has been published as a trial-use guide on December 10, 2014 valid for 2 years Without a PAR to continue its revision for a full-use guide, the standard will expire in 2016 A new initiative to form a working group is now under way with support from the Electric Machines Committees within IEEE Power and Energy and Industry Applications Societies Contact Dan M. Ionel, PhD, FIEEE, Professor and L. Stanley Pigman Chair in Power Director, University of Kentucky Chair, IEEE Power and Energy Society Electric Motor Subcommittee dan.ionel@uky.edu; dan.ionel@ieee.org PM Machine Testing CWIEME Berlin, May 2016 24

IEEE 1812 Simulation Implementation - Inductance I sc = V oc 3X s PM Machine Testing CWIEME Berlin, May 2016 25

Motor-CAD Example Study for Inductance Calculation Nissan Leaf IPM V oc X s f L S 215.15 V 0.31 Ohm 200 Hz 0.25 mh Short circuit test values are tabulated The test could be used to determine a value of L d The field distribution under motor normal operation is different to the one at shortcircuit. PM Machine Testing CWIEME Berlin, May 2016 26

Example IEEE 1812 Simulation Implementation Heath Run PM Machine Testing CWIEME Berlin, May 2016 27

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. PM Machine Testing CWIEME Berlin, May 2016 28

Example Parameters for Power Electronic Drives (VFD) Parameters required Motor rated capacity Motor rated current No. of poles Stator resistance d-axis inductance q-axis inductance Back emf constant Mandatory parameters Rated motor voltage Rated motor current Rated motor power Rated motor speed Rated motor frequency Optional parameters Motor pole pair number Torque constant Rated magnetization/short circuit current Max. speed Pole position information Optimum load angle Moment of inertia Resistance Stator inductance D-axis inductance Reluctance torque constant Source: YASKAWA ELECTRIC TOEP C710606 47C YASKAWA AC Drive V1000 Quick Start Guide Source: SIEMENS SINAMIX S120 Function Manual 07/2007 PM Machine Testing CWIEME Berlin, May 2016 30

Developments Considered for Inductance Measurement Drafted during the original development of IEEE 1812 for d and q axes measurement Not incorporated in the released version. PM Machine Testing CWIEME Berlin, May 2016 31

Equivalent Circuits for PM Machines L d and L q are functions of current components Cross coupling between the d and q axes is present, in principle Conventional equivalent circuits of PM machines do not include core losses. ωλ q i d R L d V d d axis equivalent circuit i q ωλ d R L q V q Phasor diagram q axis equivalent circuit PM Machine Testing CWIEME Berlin, May 2016 32

Inductance Measurement at Standstill Variable voltage supply and locked rotor at different positions Inductance determined as: R = P I 2, Z = V I, X = Z 2 R 2 L ll = X 2πf Max associated with L q and min with L d. PM Machine Testing CWIEME Berlin, May 2016 33

Alternative Methods for dq Inductance Measurements Standstill inductance measurements with sinusoidal or PWM voltages Procedure to align using the B and C phases Measurements using A phase Alignment along d axis Alignment along q axis Measurements under actual running conditions No load; motor driven at constant speed; I q = 0; I d is varied; load angle is considered 0; determine L d Full load; L q ; I d = 0; load angle = power factor angle; determine L q Source: H. B. Ertan and İ Şahin, "Evaluation of inductance measurement methods for PM machines," International Conference on Electrical Machines (ICEM), 2012 XXth, Marseille, 2012, pp. 1672-1678. PM Machine Testing CWIEME Berlin, May 2016 34

Non-linearity of Flux Linkages and Cross Coupling Effects Flux linkages for a dq model considering saturation and cross coupling: Ψ dd (i d ) d-axis flux linkage due to d-axis current Ψ dq (i q ) d-axis flux linkage due to q-axis current. Source: D. M. Ionel, M. J. Balchin, J. F. Eastham and E. Demeter, "Finite element analysis of brushless DC motors for flux weakening operation, IEEE Transactions on Magnetics, vol. 32, no. 5, pp. 5040-5042, Sep 1996. PM Machine Testing CWIEME Berlin, May 2016 35

Non-linearity of Flux Linkages and Cross Coupling Effects d axis flux linkage: The PM flux: Both Ψ dd (i d ) and Ψ dq (i q ) include contributions from the PM flux, which is subtracted, yielding two possible models: Source: D. M. Ionel, J. F. Eastham, E. Demeter, M. J. Balchin, D.Stoia and C. Apetrei, Different Rotor Configurations for BLDC Motors Operating in Flux Weakening Mode" in International Conference on Electric Machines, 1996 PM Machine Testing CWIEME Berlin, May 2016 36

Non-linearity of Flux Linkages and Inductances Run FEA with I d = 0 and non-zero I q and calculate the three phase flux linkages. The PM flux is obtained as: Run FEA with both I d and I q non zero, and three phase flux linkages are calculated. L d and L q are obtained as: Source: Peng Zang, A Novel Design Optimization of a Fault-Tolerant AC Permanent Magnet Machine-Drive System, PhD Dissertation, Marquette University, 2013. PM Machine Testing CWIEME Berlin, May 2016 37

Separation of Losses Loss at the test points Coefficients Residuals Determination of β provides information about the different loss components of loss. Source: G. Heins, D. M. Ionel, D. Patterson, S. Stretz and M. Thiele, "Combined Experimental and Numerical Method for Loss Separation in Permanent-Magnet Brushless Machines," in IEEE Transactions on Industry Applications, vol. 52, no. 2, pp. 1405-1412, March-April 2016. PM Machine Testing CWIEME Berlin, May 2016 38

Separation of Losses Philosophy loss components have different relationships with current and speed, based on which the separation (segregation) can be performed. Source: G. Heins, D. M. Ionel, D. Patterson, S. Stretz and M. Thiele, "Combined Experimental and Numerical Method for Loss Separation in Permanent-Magnet Brushless Machines," in IEEE Transactions on Industry Applications, vol. 52, no. 2, pp. 1405-1412, March-April 2016. PM Machine Testing CWIEME Berlin, May 2016 39

HIL Principles Real time machine model (and power electronics) for real time digital (RTDS) / hardware in the loop (HIL) simulator Reduced order machine models minimize the requirements for computational resources The controller physically exists; other combinations are also possible. PM Machine Testing CWIEME Berlin, May 2016 41

RTDS Real Time Digital Simulator IEC 61850 communication standard for electrical substation automation systems GOOSE (Generic Object Oriented Substation Event) and SMV (Sampled Measured Values). Source: RTDS Technical Documentation, 2016. PM Machine Testing CWIEME Berlin, May 2016 42

Example HIL from RTDS Source: RTDS Technical Documentation: State of Electric Machine Models and their Applications in RTDS Real-Time Digital Simulator, 2016. PM Machine Testing CWIEME Berlin, May 2016 43

RTDS Model for PMSM Model based on the model for synchronous machine Saturation, core loss, harmonics due to back emf are neglected Source: RTDS technical documentation VSC Permanent Magnet Synchronous Machine (PMSM), 2016 PM Machine Testing CWIEME Berlin, May 2016 44

RTDS Input Parameters for PM Synchronous Machine Electrical parameters Mechanical parameters Source: RTDS technical documentation VSC Permanent Magnet Synchronous Machine (PMSM), 2016. PM Machine Testing CWIEME Berlin, May 2016 45

Simulink/Matlab Real Time Simscape blocks can be employed Input parameters for PM machine: L d, L q, moment of inertia, number of poles, voltage, back emf constant, rated current. M otor M odel Source: http://www.mathworks.com/products/simulink-real-time/ PM Machine Testing CWIEME Berlin, May 2016 46

High Fidelity Models - ANSYS Time-Decomposition-Method Transient electromagnetic FEA HPC for multiple problems New approach (TDM) - solve all time steps for one problem simultaneously Patent pending 10x faster simulations reported. t 0 t 1 t 2 t 3 t 4 t n Level 1 (MPI) Distributed Time Steps Level 2 (MT) Multithreading PM Machine Testing CWIEME Berlin, May 2016 47

Reduced Order Models for HIL Controls Systematic FEA to calculate a look-up table, e.g. phase flux linkage vs. rotor position and current Flux Linkage [Wb] Inputs currents rotor position Outputs flux linkages torque θ i [deg] Current [A] Lossless model example. Source: ANSYS technical documentation on ECE Model Creation and Applications, 2015. PM Machine Testing CWIEME Berlin, May 2016 48

Models Including Core (Iron) Losses Specific core losses components in an IPM over the entire torque speed range; estimated by FEA Source: R. Wrobel, P. H. Mellor, M. Popescu and D. A. Staton, "Power Loss Analysis in Thermal Design of Permanent- Magnet Machines A Review," in IEEE Transactions on Industry Applications, vol. 52, no. 2, pp. 1359-1368, March- April 2016. PM Machine Testing CWIEME Berlin, May 2016 49

Permanent Magnet Losses PM loss (below base speed) α I q 2 and N 2 Loss due to stator slotting α N 2 and loss due to armature reaction α N 2, I q 2 Two FEA solutions used to determine d and α. Source: X. Wu, R. Wrobel, P. H. Mellor and C. Zhang, "A computationally efficient PM power loss derivation for surface-mounted brushless AC PM machines, Electrical Machines (ICEM), 2014 International Conf., Berlin, 2014. PM Machine Testing CWIEME Berlin, May 2016 50

AC Conductor Power Losses A function of frequency and temperature and given as where P dc DC power loss, P aceffe power loss due to AC excitation of the windings and P aceffr winding power loss due to rotation of the rotor Assumption of uniform average loss distribution may yield incorrect temperature distribution. Temperature distribution calculated from detailed loss model (left) and averaged loss model (right). Source: R. Wrobel, P. H. Mellor, M. Popescu and D. A. Staton, "Power Loss Analysis in Thermal Design of Permanent- Magnet Machines A Review," in IEEE Transactions on Industry Applications, vol. 52, no. 2, pp. 1359-1368, March- April 2016. PM Machine Testing CWIEME Berlin, May 2016 51

Coupled Model in Motor-CAD and Motor-LAB Electromagnetic FE analysis, including losses Thermal calculations with equivalent circuit networks Steady state, transient, and complex duty cycles. Source: MDL technical documentation Modelling the Nissan LEAF Electric Motor, 2015. Motor-LAB Motor-CAD EMag Motor-CAD Therm PM Machine Testing CWIEME Berlin, May 2016 52

Reduced Node Thermal Model Very useful for complex (full) system simulation provided satisfactory accuracy Matrix reduction method to calculate a smaller R-C network that gives same transient thermal response Keep enough nodes to give good indication of temperatures across entire model Full model of 65 nodes versus 7 nodes in reduced model Accuracy within 1% and 7 times reduction in computational time. Source: MDL technical documentation Modelling the Nissan LEAF Electric Motor, 2015. PM Machine Testing CWIEME Berlin, May 2016 53

Summary and Acknowledgments IEEE 1812 Trial-Use Guide for Testing Permanent Magnet Machines is now available for use On-going IEEE Working Group activities focus on developments for Equivalent circuit parameters measurements Separation of losses Other related topics include High fidelity models and reduced order models Hardware in the Loop (HIL) and Real Time Digital Simulation (RTDS) Special thanks to Drs. Haran Karmaker and Vandana Rallabandi for their contributions in the preparation of this presentation The continued support of our group s academic research by Motor Design Ltd. and ANSYS, Inc. is gratefully acknowledged. PM Machine Testing CWIEME Berlin, May 2016 54

Main References IEEE 1812 Trial-Use Guide for Testing Permanent Magnet Machines, Dec. 2014. H. B. Ertan and İ Şahin, "Evaluation of inductance measurement methods for PM machines," Electrical Machines (ICEM), 2012 XXth International Conference on, Marseille, 2012, pp. 1672-1678. D. M. Ionel, M. J. Balchin, J. F. Eastham and E. Demeter, "Finite element analysis of brushless DC motors for flux weakening operation," in IEEE Transactions on Magnetics, vol. 32, no. 5, pp. 5040-5042, Sep 1996. D. M. Ionel, J. F. Eastham, E. Demeter, M. J. Balchin, D.Stoia and C. Apetrei, Different Rotor Configurations for BLDC Motors Operating in Flux Weakening Mode, in International Conference on Electric Machines, 1996. Peng Zhang, A Novel Design Optimization of a Fault-Tolerant AC Permanent Magnet Machine-Drive System, PhD Dissertation, 2013. G. Heins, D. M. Ionel, D. Patterson, S. Stretz and M. Thiele, "Combined Experimental and Numerical Method for Loss Separation in Permanent-Magnet Brushless Machines," in IEEE Transactions on Industry Applications, vol. 52, no. 2, pp. 1405-1412, March-April 2016. R. Wrobel, P. H. Mellor, M. Popescu and D. A. Staton, "Power Loss Analysis in Thermal Design of Permanent-Magnet Machines A Review," in IEEE Transactions on Industry Applications, vol. 52, no. 2, pp. 1359-1368, March-April 2016. X. Wu, R. Wrobel, P. H. Mellor and C. Zhang, "A computationally efficient PM power loss derivation for surface-mounted brushless AC PM machines," Electrical Machines (ICEM), 2014 International Conference on, Berlin, 2014, pp. 17-23. ANSYS technical documentation on ECE Model Creation and Applications, 2015. RTDS technical documentation: State of Electric Machine Models and Their Applications in RTDS Real-Time Digital Simulator, 2016. PM Machine Testing CWIEME Berlin, May 2016 55

Invitation for Participation IEEE 1812 Test Guide WG In-person formal meetings at IEEE PES Jul 2016 and IEEE IEMDC May 2017 Update planned for Coil and Winding Expo, Chicago, Oct 2016 Virtual testing initiative Forum for discussion and collaboration Lab at University of Kentucky serves as main sponsor Current supporters include ANSYS and Motor Design Ltd. with others, such as RTDS, Toshiba expressing interest Inaugural in-person meeting proposed for the Coil and Winding Expo in Chicago, IL in October 2016 Contact Dan M. Ionel, PhD, FIEEE, Professor and L. Stanley Pigman Chair in Power Director, University of Kentucky Chair, IEEE Power and Energy Society Electric Motor Subcommittee dan.ionel@uky.edu; dan.ionel@ieee.org PM Machine Testing CWIEME Berlin, May 2016 56