MODELING AND ANALYSIS OF INTERIOR PERMANENT MAGNET SYNCHRONOUS

MODELING AND ANALYSIS OF INTERIOR PERMANENT MAGNET SYNCHRONOUS MACHINE FOR HYBRID ELECTRIC VEHICLES By, LINSS T ALEX Edited By Sarath S Nair www. technologyfuturae. com

INDEX q Introduction q Modeling of IPM machines q Analysis of IPM motors q Rotor Design Topologies q Performances q Applications q IPM motors in Hybrid Electric Vehicles q Conclusions q References www. technologyfuturae. com

INTRODUCTION Ø HEVs are gaining increased attention due to their higher efficiencies and lower emissions. Ø HEV combines a smaller IC engine with a battery pack and an traction motor to drive the vehicle. Ø Requirements of traction machines include high efficiency and high performance. Ø An Interior Permanent Magnet(IPM) synchronous machine is used to obtain mechanical robustness, capability of flux weakening and high speed operation. www. technologyfuturae. com

MODELING OF IPM MACHINES ØA one pole pitch cross sectional view of a 6 -pole IPM machine with tangential magnet configuration www. technologyfuturae. com

Contd… 1. MAGNETIC MODEL Average air gap flux density, CØ=Am/Ag, flux concentration factor Br- Remanence of the magnet www. technologyfuturae. com

Contd… Also, Parameters of above equations, www. technologyfuturae. com

Contd… g-air gap length Kc-Carter coefficient μrec -relative recoil permeability Amm=t. l, cross-sectional area of the iron bridge above the nonmagnetic barriers. t - Bridge width l-motor stack length. Bs-limit of leakage flux density in the bridge due to saturation. www. technologyfuturae. com

Contd… Maximum value of first harmonic of the PM flux linkage, Kwl-winding factor Nph-winding turns per phase P-number of pole pairs α-pole arc to pole pitch ratio D-inner diameter of stator www. technologyfuturae. com

Contd… The d-axis and q-axis inductances, www. technologyfuturae. com

Contd… Where Kd and Kq are defined as, ge- effective air gap, www. technologyfuturae. com

Contd… 2. ELECTRICAL MODEL Flux distribution in the air gap is assumed to be sinusoidal and the iron loss and magnetic saturation are not considered. www. technologyfuturae. com

Contd… From the motor vector diagram voltage equations are, The motor torque, www. technologyfuturae. com

Contd… Ø id Ø and iq are the d-axis and q-axis components of stator current vector Is. Magnitude of stator current vector is, Ø The design optimization is carried out under the condition of maximum torque per Ampere control www. technologyfuturae. com

Contd… www. technologyfuturae. com

Contd… Flux linkage and inductances can be normalized as, www. technologyfuturae. com

ANALYSIS OF IPM MOTORS Ø IPM motor is an induction start but synchronously run high efficiency motor. Ø IPM must overcome the magnet brake torque during starting process. Ø Developed power Pd is, www. technologyfuturae. com

Contd… Ø In IPM motors inserting permanent magnets in various arrangements and magnet polarity orientations below the conduction cage of the IPM rotor. Ø An IPM motor develops driving torque due to both permanent magnet excitation and reluctance variation. Ø Developed torque Td is, www. technologyfuturae. com

Contd… Ø First term is permanent magnet excitation torque component. Ø Second term is reluctance torque component Ø Efficient utilization of reluctance torque component is most critical for intensive flux weakening operations and efficiency improvements in HEV and electric traction drive. www. technologyfuturae. com

ROTOR DESIGN TOPOLOGIES Ø Nd. BFe magnets having high B and very large H is used for rotor design. Ø Two types 1)Straight type 2) V-type Ø Straight type has buried permanent magnet materials www. technologyfuturae. com

Contd… ØV shape rotor with permanent magnets having polarity arrangement without conduction cage for optimum air-gap flux is used in HEV and traction application. www. technologyfuturae. com

Contd… Ø Torque to weight ratio significantly improved by operating the IPM motor at 650 -Vdc from smart dc -dc converter. Ø The light load loss decreased primarily by employing high-grade silicon steel. www. technologyfuturae. com

PERFORMANCES Ø 3 -phase, 4 -pole, Y-connected, 200 V 1 hp IPM motor with Nd. BFe magnets comparing with a. 6 k. W, 3 phase, 4 -pole, 200 V induction motor www. technologyfuturae. com

Contd… Ø The efficiency and power factor as well as their product of the IPM motor is over 35% better than that for identical rated induction motor. Ø The energy efficiency aspect is a key factor for wide spread high performance applications of IPM motor drives. www. technologyfuturae. com

APPLICATIONS Ø Ventilation fans Ø Air conditioner/heat pump compressors Ø Cranes Ø Lift/escalators Ø Blood pumps Ø Ship propellers Ø Electric locomotive traction drives Ø Electric and Hybrid Electric Vehicles www. technologyfuturae. com

IPM MOTORS IN HYBRID ELECTRIC VEHICLES Ø IPM motors provides wider torque-speed range under severe size, weight and cost constraints. Ø IPM motors fulfill the requirements for smooth vehicle propultion, low vibration/noise and high degree of driving comfort. www. technologyfuturae. com

Working of IPM motor in Hybrid Electric Vehicles Low Speed www. technologyfuturae. com

Contd… Cruising www. technologyfuturae. com

Contd… Braking www. technologyfuturae. com

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Contd… Ø At 650 V level, a new reduction gear is incorporated for further reduction in axle torque to about 50%, thereby reduce motor size significantly. www. technologyfuturae. com

Application of IPM motors in HEVs www. technologyfuturae. com

CONCLUSIONS Ø Modeling and analysis of IPM machines were discussed. Ø Rotor design features for specific applications was studied. Ø Comparative performances of IPM and induction motors was discussed. Ø Several examples of successful applications were high lighted. Ø High performance IPM motors have emerged as the choice of energy efficient and environmentally friendly Hybrid Electric Vehicles. www. technologyfuturae. com

REFERENCES [1] M. A. Rahman, “Permanent Magnet Synchronous Motor-A review of Design Art", Proceedings of International Conference of Electrical Machines-ICEM’ 80, Athens, Greece, Sept. 15 -17, 1980, pp. 312 -319. [2] M. A Rahman, T. A. Little and G. R Slemon, “Analytical Models for Interior -Type Permanent Magnet Synchronous Motors”, IEEE Transactions on Magnetics, vol. MAG-21, No. 5, 1985, pp. 1741 -1743. [3] M. Kamiya, “Development of Traction Drive Motors for the Toyota Hybrid System”, Proc. IPEC-2005, Niigata, Japan, April 4 -8, 2005, pp. 14741481 [4] T. M. Jahns, G. B. Kiliman and T. W. Neumann, “Interior PM Synchronous Motors for adjustable Speed Drives”, IEEE Transactions on Industry Applications, vol. 23, No. 4 1987, pp. 681 -689 [5] M. A Rahman, “IPM Motor Drives for Hybrid Electric Vehicles”, IEEE Transactions 2007. www. technologyfuturae. com

Contd… [6] L. Chang, ”Comparison of ac drives for electric vehicles-A report on experts opinion survey, ” IEEE AES System Magz. Pp. 7 -10, Aug. 1994. [7] Arash Hassanpour Isfahani and Siavash Sadeghi, “Design of a Permanent Magnet Synchronous Machine for the Hybrid Electric Vehicle”, IEEE Trans. vol. 45, pp. 566 -570, Dec 2007 www. technologyfuturae. com

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