Motors for Electric Cars Opportunities for Industrial Motors?

Transkript

1 Motors for Electric Cars Opportunities for Industrial Motors? Martin Doppelbauer Univ.-Prof. Dr.-Ing. KIT Universität des Landes Baden-Württemberg und nationales Forschungszentrum in der Helmholtz-Gemeinschaft

2 Table of contents Martin Doppelbauer Univ.-Prof. Dr.-Ing. Karlsruhe Institute of Technology (KIT) Institute of Electrical Engineering (ETI) Kaiserstraße Karlsruhe, Germany Introduction to HEVs and Evs Typical Motor Performance Characteristic Lifetime Requirements New Design Elements Winding Design Rotor Design Soft Magnetic Material Increased Top Speed Improved Cooling Power Density 2

3 Hybrid- and EV-Classes 3

4 Drives for Hybrid and Full Electric Vehicles GEM (Gearbox integrated motor) TEM (Traction motor) Type: PMSM Voltage: 48 V or 100/120 V Max. Speed: up to /min Rated Power: up to 25 kw (48 V) or up to 60 kw (120 V) mostly constant flux Type: PMSM (BMW i3, VW,...) SPSM (Renault Zoe) IM (Tesla Model S, X) Voltage: 320 V V Max. Speed: up to /min Rated Power: up to 250 kw always field weakening (about 1:3) PMSM Permanent-Magnet Synchronous-Machine SPSM Salient-Pole Synchronous-Machine IM Induction Machine Images: KIT, Schäffler AG 4

5 TEM Performance Chart PMSM-TEM P max = 185 battery: U max = 325 V P dauer = 140 battery: U max = 230 V P dauer = 100 kw constant flux constant torque field weakening (reduced flux) constant power 5

6 Industrial Motor Performance Chart Induction Motor 2p = 4 P N = 3,7 kw f N = 50 Hz U N = 400 V I N = 6,1 A Field weakening mostly unused in industrial applications Image source: SEW Eurodrive, Bruchsal 6

7 Lifetime Requirements Industrial motors Operating hours > h Lifetime > 20 years Often variable frequency operation with long power lines, switching frequencies between 2 khz... 8 khz Utilized according to insulation class 130 (B), built with 155 (F) material Mostly continuous operation Traction Motors for Cars Operating up to h Lifetime around 12 years (160 tkm) Always variable frequency operation with short power lines, switching frequencies between 10 khz khz Utilized according to insulation class 155 (F), sometimes even 180 (H), but only on rare occasions (high speed motorway). Highly intermittent operation 7

8 Winding Design GEM (Gearbox integrated motor) TEM (Traction motor) Single tooth winding (concentrated winding) PMSM only Hairpin winding (form wound) Mostly PMSM Distributed winding (random wound) PMSM, SPSM, IM Mostly used for GEM Mostly used for TEM Mostly used for TEM Rectangular or round wire Rectangular wire Round wire Fully automized, rather simple winding machines Fully automized, but complex winding and welding machines Complex manufacturing, some hand work required 8

9 Rotor Design PMSM L d = L q L d < L q L d < L q L d << L q Surface Magnets (Constant Torque Applications Only) Burried Magnets (I-Type) Typical in GEM / ISG / BSG Burried Magnete (V-Type) Burried Magnete (U-Type) Typical in TEM Servo-Motor (SEW Eurodrive) Toyota Prius SourceVAC AUDI AG Diss. F. Bittner 9 M ~ i q i d = 0 i q 0 i d 0

10 Soft Magnetic Material (Lamination) Nickel Iron Permenorm 5000V5 high µ average Js Silicon Iron Trafoperm N4 average µ average Js Cobalt Iron Vacoflux 50 average µ highest Js Typical material in traction motors is M235-35A 10

11 Increased Top Speed Typical Range of BEV Traction Drives 11

12 Cooling Water Jacket Cooling Long thermal path from heat source (wire) to sink (water) Inlet temperatures of 50 C C Metal housing with good thermal conductivity required 12

13 Cooling Direct Slot Cooling Conventional Slot cooling Round wire Cooling channels Rectangular wire Water cooling jacket Form wound with high filling factor Empty slot areas used for cooling Cooling channels with foil tubes are created during impregnation 13

14 3 2 Cooling Spray Cooling and Rotor Injection Lance 1 1. Radial oil-fog cooling of winding overhangs 2. Axial oil-fog cooling of winding overhangs 3. Transmission of cooling oil through the shaft (ASM, FESM) 14

15 Cooling Stator, cooling and end shield moulding One shot moulding Stator housing B-flange end-shield Cooling channels Winding connection Sensor connection (temp, speed) 15

16 Formula Student KA-RaceIng KIT16e km/h 2,5 s Car Weight 195 kg Top Speed 116 km/h Battery Capacity 6,5 kwh Cont. Power 4 x 30 kw Peak Power 4 x 50 kw Motor Type PMSM PMSM Top Speed /min /min Total Weight 5,3 kg 4,1 kg Power Density in S1-Operation 0,21 kg/kw (4,7 kw/kg) 0,14 kg/kw (7,3 kw/kg) 16

17 Power Density 17

18 Impact on Industrial Motors? High demand of high quality electrical lamination (M235-35A) Short term: Price increase and shortage of material Long term: Price reduction? High demand of rare-earth permanent-magnets Short term: Price increase and shortage of material Long term: Price reduction? New cooling designs No impact as water cooling is not feasible Increased top speed and power density No impact as high top speed is not feasible Improved winding design Short term: Increased delivery times of winding machines Long term: Improved automization, lower production cost, increased quality 18

19 Thanks for your attention Questions? 19