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SRMs in HEV applications
Comparison of electrical machines for HEVs
SRMs in HEV applications
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Wheel loader
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It weighs over 180 tones
21m³ rock bucket handles a 38
tone payload
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141:1 planetary gearbox
300kW / motor
20,000 hours life for the
bearings
SRMs in HEV applications
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Hybrid bus drive
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2x SR drives (50kW and 160kW)
One combustion engine (2.5L Di)
Low loss Li-Pol battery
No gearbox
CO2 emissions lower with 40%
Fuel consumption lower with 30%
SRMs in HEV applications
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SR drive variator system for Renaul TIVA
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The two SRMs are not in line any more
The gearbox is excluded
Infinite gear steps are obtained
The SRMs have 25kW
Speed range from 1800rpm to 11000rpm
Maximum torque of 135Nm
Diameter: 192mm
Active length: 160mm
Voltage: 425V
SRMs in HEV applications
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Starter alternator unit for trucks
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Power: 30kW
Voltage: 340V
Torque: 1200Nm
SRMs in HEV applications
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Starter alternator technology:
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65Nm torque, 2kW power
3kW power in generator regime
Sensorless position control
Inverter based on MOSFET tech.
 AC
Induction
 Brushless DC
 Switched Reluctance
AC Induction
Source: “AC, Brushless, Switched Reluctance Motor Comparisons” James R. Hendershot, Magna Physics Corporation
Brushless DC
Source: “AC, Brushless, Switched Reluctance Motor Comparisons” James R. Hendershot, Magna Physics Corporation
Switched Reluctance
Source: “AC, Brushless, Switched Reluctance Motor Comparisons” James R. Hendershot, Magna Physics Corporation
Source: “AC, Brushless, Switched Reluctance Motor Comparisons” James R. Hendershot, Magna Physics Corporation
Motor Comparison for BEVs & HEVs
PMBDC
IM
SRM
Brushed DC
Speed [rpm]
1000
1000
1000
1000
Torque [Nm]
2866
2866
2866
2866
Max. Speed [Nm]
4000
4000
4000
4000
Torque [Nm]
716
716
716
716
Voltage [V]
380
380
190/300
500
Current [A]
753-486
980-630
1000/500
520
Frequency [Hz]
156
133
500
133
Weight [kg]
300
600
500
1000
Power [kW]
300
300
300
300
Efficiency %
@1000 rpm
@4000 rpm
95
97
93
95
94
96
85
89
Cooling
Oil
Oil
Oil
Air
Source: Lightweight Electric/ Hybrid Vehicle Design Ron Hodkinson and John Fenton
In Summary
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Due to the absence of rotor windings, SRM is very simple to construct, has
a low inertia and allows an extremely high-speed operation. SRM operates
in constant torque from zero speed up to the rated speed. Above rated
speed up to a certain speed, the operation is in constant power. The range
of this constant power operation depends on the motor design and its
control.
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The brushless DC/AC has the benefit of embedded energy source, high
torque densities and high speed rage. Already implemented on the Toyota
Prius and Toyota SUV proved to have a good behavior in HEVs
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The induction machines are a candidate in the fields of HEVs too. Them
manufacture already reached a lot of experience during time and several
optimization research activities were performed to push the limits of them
performances. Studies proved that using them “in wheel”, like in the case of
Audi E-Tron reached the request of fast and easy to control HEV.
Thank you for your attention !