SRMs in HEV applications

Comparison of electrical machines for HEVs

SRMs in HEV applications

Wheel loader It weighs over 180 tones 21m³ rock bucket handles a 38

tone payload

141:1 planetary gearbox 300kW / motor 20,000 hours life for the

bearings

SRMs in HEV applications Hybrid bus drive

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

SR drive variator system for Renaul TIVA 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

Starter alternator unit for trucks Power: 30kW Voltage: 340V Torque: 1200Nm

SRMs in HEV applications

Starter alternator technology: 65Nm torque, 2kW power 3kW power in generator regime

Sensorless position control Inverter based on MOSFET tech.

AC InductionBrushless DCSwitched 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

9597

9395

9496

8589

Cooling Oil Oil Oil Air

Source: Lightweight Electric/ Hybrid Vehicle Design Ron Hodkinson and John Fenton

In Summary 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.

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

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 !