ELECTRIC VEHICLE POWERTRAIN DEVELOPMENT- CONCEPTUAL DESIGN AND IMPLEMENTATION

Transcription

1 ELECTRIC VEHICLE POWERTRAIN DEVELOPMENT- CONCEPTUAL DESIGN AND IMPLEMENTATION Mustafa Karamuk Mehmet Çepni Sedat Gür

2 Contents Consumer Surveys, Policy of Governments and Actual Figures on Electric Vehicles Conceptual Design Steps of an Electric Vehicle Electrical Machines for Electric Vehicles Electric Vehicle Project at OTAM Development Methodology of Motor Drives at OTAM Development of Interior Permanent Magnet Synchronous Motor Drive Development of Vehicle Control Unit (VCU) Development of VCU- Simulation Results, Experimental Setup On-going Activities in the Project

3 FOUNDED 2004 Founded by the collaboration of Automotive Manufacturers Association (OSD), The Scientific and Technical Research Council of Turkey (TUBITAK) and Istanbul Technical University (ITU) to perform the following missions: to increase University Industry Collaboration. to sustain the competitiveness of the National Automotive Industry in global scale. to provide research and development projects and product testing for the automotive industry and its suppliers, in cooperation with the university. CORPORATION 2007 In 2007, OTAM became a corporation with the shareholders ITU, OSD, TAYSAD and OIB Today, OTAM is shown as the most successful University Industry collaboration in Turkey. OTAM has accomplished more than 100 R&D Projects since its establishment. O T A M A U T O M O T I V E T E C H N O L O G I E S R & D C O M P A N Y.

4 Istanbul Technical University Foundation Automotive Manufacturers Association Association of Automotive Parts and Components Manufacturers Exporters Union of Automotive Industry O T A M A U T O M O T I V E T E C H N O L O G I E S R & D C O M P A N Y.

5 OTAM ( Automotive Technologies R&D Center) is an Engineering Company, located at technopolis area at Istanbul Technical University. Provides engineering solutions within areas of Test, Product Development, R&D Projects, Analysis & Special Test System Development Main Industries: Automotive Sector, Defence Industy & Railway Industry Other Sectors: Machine Producers, White Goods & Marine Industries O T A M A U T O M O T I V E T E C H N O L O G I E S R & D C O M P A N Y.

6 CONSUMER SURVEYS, POLICY of GOVERNMENTS, and ACTUAL FIGURES on ELECTRIC VEHICLES

7 Electric Vehicles Technology- Consumer Surveys by Deloitte Critical survey conducted by Delloitte among people in 17 countries on 5 continents from November 2010 to May 2011 reveals consumer expectations. Countries surveyed include Argentina, Australia, Belgium, Brazil, Canada, China, France, Germany, India, Italy, Japan, Korea, Spain, Taiwan, Turkey, the UK and the US.* Significant gap exists between consumer expectations and current electric vehicle technology. Consumers felt that EVs should be able to go farther,on less charge time, for a cheaper price than automakers are currently able to offer. * Expected recharge time in two hours or less Despite the willingness to consider an EV, many seem not willing to compromise in key criteria such as range. Technology improvements in gasoline and diesel engines, as well as start-stop idle technologies and reductions in vehicle weight, are pushing fuel efficiency very close to the 50 miles per gallon (mpg) mark. In case of 50 mpg fuel efficiency, consumers in China (57 %) and US (68%) are less likely consider EVs. * *

8 Electric Vehicles Technology- Policy of Governments With more research and incentives we can break our depencence on oil with biofuels, and become the first country to have a million electric vehicles on the road by President Barack Obama, 2011 State of the Union * **** Chancellor Angela Merkel reaffirmed her target to bring one million electric cars on to German roads By the end of the decade despite evidence of dwindling consumer interest. ** ***** Swedish Governments Vision: Oil-free society by the year 2020 *** Road transport, including transport in the agricultural, forestry, fisheries and building sectors, should reduce use of petrol and diesel by percent by * US Department of Energy-February 2011 Status Report ** *** ** ** *****

9 Electric Vehicles Technology- Actual Figures EV Stock: Cumulative Registration/Stock of Electric Vehicles, 2012 * The Electric Vehicles Initiative is a multigovernment policy forum dedicated to accelerating the introduction and adoption of electric vehicles worldwide. EV Stock in EVI Countries * Global EV Outlook-April 2013 /

10 ELECTRIC VEHICLE CONCEPTUAL DESIGN

11 Conceptual Design Steps of an Electric Vehicle Powertrain System Estimated drive cycles have crucial importance for specifications of high voltage battery, traction motor, drive system and gear ratio Regeneration capability and range as well * *Ref. [5]

12 Electric Vehicle Conversion or New Design Electric Vehicle? Electric vehicle major components: High voltage Li-Ion battery Electrical machine and drive system Vehicle Control Unit DC-DC Converter Gearbox ( 1- or 2-speed transmission system) Cooling and heating system Charging system Wiring harness specific for electric vehicle Decision criteria between Conversion and New Design Target performance index Market segment Cost of subcomponents and R&D Suppliers Production volume Performance index Range Acceleration time Driveability Total weight NVH performance ( noise-vibrationharshness ) Efficiency of subcomponents Efficiency of regenerative brake Charging time Hardware, software and functional reliability Safety measures for high voltage system Vehicle performance around zero and minus temperatures

13 Electrical Machines for Electric Vehicles Global facts: China holds % 87.5 of rare earth elemenst. Government of China cuts production of magnets for environmental reasons and meantime magnet prices are increasing dramatically. Although widespread use of Interior Permanent Magnet Synchronous Machine for Hybrid Electric Vehicles, magnet supply and cost problems led to search of alternative electrical machines. US funds R&D projects for electric motors without rare earth elements. * * electronics360.globalspec.com OTA M AU TO M OT I V E T E C H N O LO G I E S R & D C E N T E R

14 Electrical Machines for Electric Vehicles Induction Machine Interior Permanent Magnet Synchronous Machine (IPMS Machine) Separately excited synchronous machine (applied in Renault e-cars) Permanent magnet assisted synchronous reluctance machine (PMAS Reluctance Machine) Switched reluctance machine (HEVT from USA has patented technology for electric vehicles) Most commonly used electrical machines for electric vehicles Alternative electrical machines for electric vehicles Despite the technical advantages like high torque/volume and efficiency, IPMS machine has unstabile price for suppliers and OEMs. Therefore, electrical machines without a rare earth elements are being developed. Induction Machine [1] IPMS Machine [2] PMAS Reluctance Machine [3] Switched Reluctance Machine [4] OTA M AU TO M OT I V E T E C H N O LO G I E S R & D C E N T E R

15 Electrical Machines for Electric Vehicles Design Requirements and Critical Parameters for Electric Vehicles Insulation class H Water cooling is required both for electrical machine and inverter. Because the drive cycles, including the increase in ambient temperature, imposes thermal stress on EM and inverter as well. Short term overload capability. The range of peak torque to maximum continuous torque should be 1.5 to 2. Maximum speed to nominal speed ratio, e.g. wide field weakening range. Ratio of 3:1 or 4:1 is common in practice. Design voltage considering the battery minimum and maximum voltage range Maximum continuous torque and peak torque for grade and acceleration requirement Maximum speed considering the gearbox ratio Efficiency map. This is related to power demand for cooling of electrical machine, drive system and the battery for estimated drive cycles, heating of the battery for minus temperatures as well. Protection class IP6K7 Weight Geometrical integration into vehicle Cost and supplier

16 ELECTRIC VEHICLE PROJECT at OTAM

17 Outputs of the project : Drive system of IPMS Machine ( design of power electronics and control board and software including the vector control algorithm VCU hardware and software including the control algorithm and CAN I/O User interface for calibration The main specifications of the high power motor drive in the project : 75 kw nominal, 150 kw peak power Input voltage range of the inverter is between V DC Switching frequency is 10 khz Space Vector Modulation Max. speed up to rpm CAN interface for communication with VCU Water cooling

18 Development Methodology of Motor Drives at OTAM Performance requirements of the vehicle Electrical design requirements (e.g. Battery voltage, power limits) Design verifications at low power motor drive Upgrade of of design for high power motor drive Power Electronics design and simulation in Althium Designer Control System design and simulation in Matlab- Simulink Implementation in Texas F28335 DSP via Embedded Coder Test of prototype Further improvements EMC/EMI Tests Test of control system Test of hardware design Comparison with simulation and inital design requirements Design of high power motor drive for Electric Vehicle O T A M A U T O M O T I V E T E C H N O L O G Y A N D R E S E A R C H C E N T E R

19 Development of Interior Permanent Magnet Synchronous Motor Drive Vector Control Principle Diagram

20 Mathematical Model of Interior Permanent Magnet Synchronous Machine Vector Control including the Maximum Torque Per Ampere Strategy U sd = R s i sd + L sd di sd dt U sq = R s i sq + L sq di sq dt ω r L sq i sq (1) + ω r (L sd i sd + ψ pm ) (2) T e = 3 2 p ψ pm i sq + (L sd L sq ) i sd i sq (3) i sd_ref = ψ 2 pm ψ pm +8 (Lsq L sd ) 2 i2 s 4 (L sq L sd ) i s = i 2 2 sd + i sq i smax (5) (4) Where, U sd,u sq : d and q-axis voltages [V] i sdref, i sqref : d and q-axis current controller references [A] i sdact, i sqact : d and q-axis actual currents [A] i s : Phase current ψ pm : Rotor permanent magnet flux [Wb] T e : Motor torque [Nm] p : Pole pair number L sd, L sq : Stator d and q-axis inductances [H] R s : Stator resistance [Ohm] I smax : Motor/inverter current limit [A] U smax : Inverter voltage limit [V] U dc : DC-link voltage actual value [V] : Rotor electrical speed (rad/s) ω r U s = U 2 2 sd + U sq U smax (6) U smax = U dc 3 (7)

21 Implementation of Simulink Blocks on Texas DSP via Embedded Coder

22 Motor Drive System-Experimental Setup Motor drive has been tested on 2 kw Yaskawa Interior Permanent Magnet Synchronous Machine. Load machine is also a 2 kw Permanent Magnet Synchronous Machine of Control Techniques. Parameters of Yaskawa IPMS Machine is given below: Parameter Value Unit Number of pole 6 - Rated power 2.2 kw Rated speed 1750 rpm Rated torque 12 Nm Rated voltage (rms) 373 V Rated current 4.1 A Stator resistance 3.29 Ohm d-axis inductance mh q-axis inductance mh Rotor inertia 10.07x10-3 kgm 2

23 Comparison of Test and Simulation Results of Motor Drive System Acceleration to 500 rpm and torque step at 10 Nm load -measurement Motor current at 10 Nm load-measurement (RMS value: 3.34 A) n-ref (rpm)*0.05 n-act (rpm)*0.05 T-motor-act (Nm) Isa (A) ( motor phase current) 10 data t (s) t (s) Acceleration to 500 rpm and torque step at 10 Nm load-simulation Motor current at 10 Nm load simulation (RMS value: 3.21 A)

24 Comparison of Test and Simulation Results of Motor Drive System Isq current at 10 Nm load-measurement Isd current at 10 Nm load-measurement Isq-ref (A) Isq-act (A) Isd-ref (A) Isd-act (A) t (s) t (s) Isq current at 10 Nm load-simulation Isd current at 10 Nm load-simulation

25 Development of Vehicle Control Unit (VCU) Design Requirements Vehicle Segment E&E Architecture of the Vehicle Review of Patents Vehicle Integration and Road Tests Conceptual Design Software and Hardware Requirements EMC/EMI Tests Simulation Platform Control System Software Homologation Requirements Automotive Standards (e.g. ISO 26262) CAN I/O Interface with Peripheral Units

26 Development of Vehicle Control Unit (VCU) OTAM VCU Topology OTAM VCU Hardware Design General purpose VCU hardware has been designed in Althium Designer Assembly and test of prototype hardware is on-going. Control System Models have been developed in Simulink CAN communication with an industrial drive has been implemented on the mototr test bench.

27 Development of VCU- Simulation Platform Main modules in VCU simulation platform: Human driver model VCU Inverter and electrical machine model Gearbox Vehicle model Mechanical brake model Battery model

28 Development of VCU-Simulation results Simulation of electric vehicle controlled by VCU. Emergency shutdown is applied at t=736 s. The real prototype vehicle data is used in this Example ( max vehicle weight is 6000 kg).

29 Experimental Setup CAN Communication between VCU and an Industrial Motor Drive VCU models have been tested on a 2.2 kw motor test bench. Main purpose of this configuration is to establish the CAN communication between VCU and electric powertrain drive and send torque reference via VCU torque control model, monitor the status of the motor drive via CAN bus, and apply other test conditions to test VCU software.

30 On-going Activities in the Project Development of High Power ( 75/150 kw) Motor Drive-Power Electronics and Control System Software Development of High Power (75/150 kw) Test Bench Hardware Design of VCU

31 References [1] D. Bücherl et. al., Comparison of Electrical Machine Types in Hybrid Drive Trains: Induction Machine vs. Permanent Magnet Synchronous Machine, Proceedings of the 2008 International Conference on Electrical Machines [2] S. Wu, L. Tian, S. Cui, A comparative Study of teh Interior Permanent Magnet Electrical Machine s Rotor Configuration for a Single Shaft Hybrid Electric Bus, IEEE Vehicle Power and Propulsion Conference (VPPC), September 3-5, 2008, Harbin China [3] I. Boldea, L. Tutelea, C. I. Pitic, PM-Assisted Reluctance Synchronous Motor/Generator (PM-RSM) for Mild Hybrid Vehicles: Electromagnetic Design, IEEE Transactions on Industry Applications Vol. 40, No. 2, March/April 2004 [4] M. T. DiRenzo, Switched Reluctance Motor Control-Basic Operation and Example Using the TMS320F240, Texas Instruments Application Report [5] Ergeneman, M., Soruşbay, C. and Göktan, A.G., Estimation of Greenhouse Gas Emissions Related to Urban Driving Patterns, ICAT 2010, Int Conference on Energy and Automotive Technologies, Four Seasons Hotel, Istanbul, 5th Novem- ber 2010

32 THANK YOU FOR YOUR ATTENTION