SRMs in HEV applications Comparison of electrical machines

SRMs in HEV applications Comparison of electrical machines for HEVs

SRMs in HEV applications n Wheel loader q q It weighs over 180 tones 21 m³ rock bucket handles a 38 tone payload q q q 141: 1 planetary gearbox 300 k. W / motor 20, 000 hours life for the bearings

SRMs in HEV applications n Hybrid bus drive q q q 2 x SR drives (50 k. W and 160 k. W) One combustion engine (2. 5 L Di) Low loss Li-Pol battery No gearbox CO 2 emissions lower with 40% Fuel consumption lower with 30%

SRMs in HEV applications n SR drive variator system for Renaul TIVA q q q q q The two SRMs are not in line any more The gearbox is excluded Infinite gear steps are obtained The SRMs have 25 k. W Speed range from 1800 rpm to 11000 rpm Maximum torque of 135 Nm Diameter: 192 mm Active length: 160 mm Voltage: 425 V

SRMs in HEV applications n Starter alternator unit for trucks q q q Power: 30 k. W Voltage: 340 V Torque: 1200 Nm

SRMs in HEV applications n Starter alternator technology: q q 65 Nm torque, 2 k. W power 3 k. W power in generator regime Sensorless position control Inverter based on MOSFET tech.

n AC Induction n Brushless DC n 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 Torque [Nm] 2866 Max. Speed [Nm] 4000 Torque [Nm] 716 716 Voltage [V] 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 [k. W] 300 300 Efficiency % @1000 rpm @4000 rpm 95 97 93 95 94 96 85 89 Cooling Oil Oil Air Source: Lightweight Electric/ Hybrid Vehicle Design Ron Hodkinson and John Fenton

In Summary n 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. n 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 n 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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