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

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

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

4. MODELING OF IPM MACHINES
A one pole pitch cross sectional view of a
6-pole IPM machine with tangential magnet configuration

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

6. Contd…
Also, Parameters of above equations,

7. 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.

8. 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

9. Contd…
The d-axis and q-axis inductances,

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

11. 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.

12. Contd…
From the motor vector diagram voltage equations are, The motor torque,

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

14. Contd…

15. Contd… Flux linkage and inductances can be normalized as,

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

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

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

19. ROTOR DESIGN TOPOLOGIES
NdBFe magnets having high B and very large H is used for rotor design.
Two types 1)Straight type 2) V-type
Straight type has buried permanent magnet materials

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

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

22. PERFORMANCES
3-phase,4-pole,Y-connected,200V 1 hp IPM motor with NdBFe magnets comparing with a .6kW,3- phase,4-pole,200V induction motor

23. Contd…
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.
The energy efficiency aspect is a key factor for wide spread high performance applications of IPM motor drives.

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

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

26. Working of IPM motor in Hybrid Electric Vehicles
Low Speed

27. Contd…
Cruising

28. Contd…
Braking

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

31. Application of IPM motors in HEVs

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

33. 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
[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
[3] M.Kamiya, “Development of Traction Drive Motors for the Toyota Hybrid System”,Proc.IPEC-2005,Niigata,Japan,April 4-8,2005,pp
[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 ,pp
[5] M.A Rahman, “IPM Motor Drives for Hybrid Electric Vehicles”,IEEE Transactions 2007.

34. 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 [7] Arash Hassanpour Isfahani and Siavash Sadeghi, “Design of a Permanent Magnet Synchronous Machine for the Hybrid Electric Vehicle”,IEEE Trans.vol.45,pp ,Dec 2007

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