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  CO 2 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 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

Motor Comparison for BEVs & HEVs PMBDCIMSRMBrushed DC Speed [rpm]1000 Torque [Nm]2866 Max. Speed [Nm]4000 Torque [Nm]716 Voltage [V] / Current [A] / Frequency [Hz] Weight [kg] Power [kW]300 Efficiency rpm CoolingOil 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.

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