by, linss t alex edited by sarath s nair technologyfuturae

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MODELING AND ANALYSIS OF INTERIOR PERMANENT

MAGNET SYNCHRONOUS MACHINE FOR HYBRID

ELECTRIC VEHICLES By,

LINSS T ALEX Edited By

Sarath S Nairwww.technologyfuturae.com


INDEX Introduction Modeling of IPM machinesAnalysis of IPM motorsRotor Design TopologiesPerformancesApplications IPM motors in Hybrid Electric VehiclesConclusionsReferences


INTRODUCTIONHEVs 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.


A one pole pitch cross sectional view of a 6-pole IPM machine with tangential magnet

configuration

MODELING OF IPM MACHINES


1.MAGNETIC MODELAverage air gap flux density,

CØ=Am/Ag, flux concentration factorBr- Remanence of the magnet

Contd…


Also,Parameters of above equations,

Contd…


g-air gap lengthKc-Carter coefficientμrec -relative recoil permeabilityAmm=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.

Contd…


Maximum value of first harmonic of the PM flux linkage,

Kwl-winding factorNph-winding turns per phaseP-number of pole pairsα-pole arc to pole pitch ratioD-inner diameter of stator

Contd…


The d-axis and q-axis inductances,

Contd…


Where Kd and Kq are defined as,

ge- effective air gap,

Contd…


2.ELECTRICAL MODELFlux distribution in the air gap is assumed to be

sinusoidal and the iron loss and magnetic saturation are not considered.

Contd…


From the motor vector diagram voltage equations are,

The motor torque,

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

Contd…


Contd…


Flux linkage and inductances can be normalized as,

Contd…


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,

ANALYSIS OF IPM MOTORS


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,

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.

Contd…


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

ROTOR DESIGN TOPOLOGIES


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

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.

Contd…


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

PERFORMANCES


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.

Contd…


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

APPLICATIONS


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.

IPM MOTORS IN HYBRID ELECTRIC VEHICLES


Low Speed

Working of IPM motor in Hybrid Electric Vehicles


Cruising

Contd…


Braking

Contd…


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

Contd…


Application of IPM motors in HEVs


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.

CONCLUSIONS


[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.1474-1481

[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.

REFERENCES


[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

Contd…

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by, linss t alex edited by sarath s nair technologyfuturae

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