Computationally efficient method for identifying manufacturing induced rotor and stator misalignment in permanent magnet brushless machines

A computationally efficient method is presented to investigate additional cogging torque harmonics resulting from misalignment of the rotor and stator caused by assembly and manufacturing tolerances in an axial flux, fractional pitch PMSM. The hybrid analytical / FEA method utilizes superposition of a pole transition over a single stator slot and is used to predict the effect on cogging torque of eccentricity misalignment in combination with pole and slot placement inaccuracies. This work extends on that previously published by inducing varying degrees of assembly misalignment of the stator and rotor to determine the effect on cogging torque waveforms. Experimental data is presented supporting the analytical data indicating that static and dynamic eccentricity produce first and second order sidebands about the rotor and stator affected harmonics respectively. There is good agreement between the hybrid analytical method, FEA and measured experimental data.

[1]  G. Heins,et al.  Decoupling manufacturing sources of cogging torque in fractional pitch PMSM , 2011, 2011 IEEE International Electric Machines & Drives Conference (IEMDC).

[2]  T.G. Habetler,et al.  Detecting Rotor Faults in Low Power Permanent Magnet Synchronous Machines , 2007, IEEE Transactions on Power Electronics.

[3]  A. Vahedi,et al.  Static Eccentricity Fault Detection in Single-Stator–Single-Rotor Axial-Flux Permanent-Magnet Machines , 2012, IEEE Transactions on Industry Applications.

[4]  Dan M. Ionel,et al.  Calculation of magnet losses in concentrated-winding permanent magnet synchronous machines using a Computationally Efficient - Finite Element method , 2012, ECCE 2012.

[5]  Greg Heins,et al.  Identifying manufacturing induced rotor and stator misalignment in brushless permanent magnet motors , 2014, 2014 International Conference on Electrical Machines (ICEM).

[6]  Jawad Faiz,et al.  Magnetic field and vibration monitoring in permanent magnet synchronous motors under eccentricity fault , 2012 .

[7]  D. Howe,et al.  Evaluation of superposition technique for calculating cogging torque in permanent-magnet brushless machines , 2006, IEEE Transactions on Magnetics.

[8]  Thomas A. Lipo,et al.  Cogging torque minimization technique for multiple-rotor, axial-flux, surface-mounted-PM motors: alternating magnet pole-arcs in facing rotors , 2003, 38th IAS Annual Meeting on Conference Record of the Industry Applications Conference, 2003..

[9]  Nicola Bianchi,et al.  Design techniques for reducing the cogging torque in surface-mounted PM motors , 2000, Conference Record of the 2000 IEEE Industry Applications Conference. Thirty-Fifth IAS Annual Meeting and World Conference on Industrial Applications of Electrical Energy (Cat. No.00CH37129).

[10]  Thomas M. Jahns,et al.  Pulsating torque minimization techniques for permanent magnet AC motor drives-a review , 1996, IEEE Trans. Ind. Electron..

[11]  Greg Heins,et al.  Accurate Torque Ripple Measurement for PMSM , 2011, IEEE Transactions on Instrumentation and Measurement.

[12]  Dan M. Ionel,et al.  Modeling and design optimization of PM AC machines using computationally efficient - finite element analysis , 2010, 2010 IEEE Energy Conversion Congress and Exposition.

[13]  F. Crescimbini,et al.  Experimental study on reducing cogging torque and core power loss in axial-flux permanent-magnet machines with slotted winding , 2002, Conference Record of the 2002 IEEE Industry Applications Conference. 37th IAS Annual Meeting (Cat. No.02CH37344).

[14]  R. Fiser,et al.  Additional Cogging Torque Components in Permanent-Magnet Motors Due to Manufacturing Imperfections , 2009, IEEE Transactions on Magnetics.

[15]  D. Howe,et al.  Influence of design parameters on cogging torque in permanent magnet machines , 1997, 1997 IEEE International Electric Machines and Drives Conference Record.

[16]  D. M. Ionel,et al.  Multi-objective optimization of PM AC machines using computationally efficient - FEA and differential evolution , 2011, 2011 IEEE International Electric Machines & Drives Conference (IEMDC).

[17]  M. L. Mohd Jamil,et al.  Influence of pole and slot number combinations on cogging torque in permanent magnet machines with static and rotating eccentricities , 2013, 2013 IEEE Energy Conversion Congress and Exposition.

[18]  A. Hartman,et al.  Undriven vibrations in brushless DC motors , 2000, 2000 Asia-Pacific Magnetic Recording Conference. Digests of APMRC2000 on Mechanical and Manufacturing Aspects of HDD (Cat. No.00EX395).

[19]  M. Thiele,et al.  Identifying cogging torque harmonics affected by misalignment in axial flux fractional pitch PMSM , 2012, 2012 XXth International Conference on Electrical Machines.

[20]  Dan M. Ionel,et al.  Automated Multi-Objective Design Optimization of PM AC Machines Using Computationally Efficient FEA and Differential Evolution , 2013, IEEE Transactions on Industry Applications.

[21]  D M Ionel,et al.  Ultrafast Finite-Element Analysis of Brushless PM Machines Based on Space–Time Transformations , 2011, IEEE Transactions on Industry Applications.

[22]  Szilard Jagasics.  Comprehensive analysis on the effect of static air gap eccentricity on cogging torque , 2010, 19th International Workshop on Robotics in Alpe-Adria-Danube Region (RAAD 2010).

[23]  Jawad Faiz,et al.  Diagnosis and performance analysis of threephase permanent magnet synchronous motors with static, dynamic and mixed eccentricity , 2010 .