An Integrated Starter-Alternator System Using Induction Machine Winding Reconfiguration

Transcription

1 2007 International Future Energy Challenge Invited Paper: An Integrated Starter-Alternator System Using Induction Machine Winding Reconfiguration Richard Moutoux Gregory Martin Richard Tan Maung Myat Geoff Sanders Dr. Frank Barnes University of Colorado at Boulder Department of Electrical and Computer Engineering

2 Presentation Outline Purpose Team System Design Performance and Results Cost and Weight Future Work Acknowledgements

3 Purpose and Motivation: : IFEC 2007 The 2007 International Future Energy Challenge (IFEC) invited undergraduate teams to compete in the design and construction of an integrated starter-generator (ISG) intended to: Provide hands-on design project as an outstanding learning experience for undergraduate students. Produce 30 Nm of starting torque at 0 rpm. Motor at constant power of 1 kw up to 3000 rpm. Smoothly transition into generating mode at 3000 rpm. Generate 1 kw at 3000 rpm with at least 75% efficiency. Meet cost and weight targets. Implement innovative design to solve a challenging automotive industry problem

4 Our IFEC Team Members University of Colorado - Boulder Maung Myat Richard Tan Geoff Sanders Gregory Martin Richard Moutoux Ankit Tripathi Marc Hesse Dr. Frank Barnes Dr. Ewald Fuchs Prof. Tom Brown Dr. Robert Erickson Dr. Dragan Maksimovic Dr. Regan Zane Indian Institute of Technology - Delhi Megha Gupta Aditya Bhatla Dhruv Vatsal Ekansh Aggarwal Ishita Mukhopadhyay Parag Arora Vineesh Kumar Dr. Bhim Singh Dr. G. Bhuvaneshwari

5 ISG System Features Off-the-shelf induction machine has been customized for pole changing and winding switching capability. Off-the-shelf inverter and micro-controller are customized to provide V/f motor control and winding switching signals. Custom switch network reconfigures machine windings as shaft speed changes. induction machine micro-controller inverter rectifier switch network excitation capacitors Rectifier and excitation capacitors generate more than 1 kw at 200 VDC.

6 Our ISG Solution: Overview Machine: Pole-changing, winding-switching squirrel-cage rotor induction machine Winding Switching: Network of electro-mechanical contactors controlled by micro-controller Motor Control: Standard 6-bridge IGBT PWM board with V/f control, controlled by micro-controller Generating: Standard 6-bridge rectifier with output capacitor to provide 200 V DC System Control: Micro-controller coordinates winding switching, motor control, and generation

7 Our ISG Solution: Machine Selected off the shelf, 3 hp, 2 pole induction motor Performed analysis, then re-wound motor for pole changing and winding switching Machine connected in 8-pole delta connection for starting, then 4-pole double-wye (parallel) and 4pole double-wye (series) to extend motoring speed range.

8 Our ISG Solution: Machine Our ISG Solution: Machine 8-pole, delta winding connection

9 Our ISG Solution: Machine Our ISG Solution: Machine 4-pole, double-wye winding connection

10 Our ISG Solution: Winding Switching Pole changing implemented using contactors to reconnect machine windings 48 switches, controlled by micro-controller Winding switching occurs when speed reaches ~800 rpm, ~2000 rpm, and generating mode.

11 Our ISG Solution: Motor Control Used ST Microelectronics inverter power board, 6 IGBTs, rated for C, C. Inverter programmed for three V/f regimes, each sweeps voltage and frequency to accelerate rotor. Voltage range 70 Vrms to 120 Vrms Frequency range 25 Hz to 100 Hz

12 Our ISG Solution: Generating Standard 6-pulse 3-phase rectifier connected to machine output leads Exciting capacitors used to excite induction machine and adjust voltage level to 200 VDC at 3000 rpm No additional filtering was added

13 Our ISG Solution: System Control ST Micro-controller board interfaces to inverter and electro-mechanical winding switches Drives inverter board for V/f control, and changes regime at input specified frequencies Produces signals that initiate machine winding reconfiguration and generating mode initiation

14 Simulated Motoring Performance

15 Competition Test Results Design concepts and basic functionality demonstrated successfully No-load acceleration from 0 to over 2200 rpm in 4 seconds (0 to 2700 rpm in 4.5 seconds achieved in CU lab) > 60% generating efficiency at 200 V DC Start-up torque of 10 Nm (22 Nm achieved in CU lab) Successful duration testing: 3 minutes at 1.2 kw generating 9 minutes at 600 W generating

16 Cost and Weight This is a very low cost solution; mass production costs are estimated at ~$ Simple, inexpensive induction machine: $60.00 Inexpensive, basic, portable control and switching electronics: $75.00 Prototype weight is not optimized (14 kg), however weight reductions of more than 6 kg are easily achievable. Aluminum housing Less back iron

17 Future Work Eliminate excitation capacitors Integrate rectifier with inverter Custom stator core design Custom double squirrel cage rotor design Inverter that can handle high current transients Improve packaging for in-situ custom installation Study pole changing permanent magnet rotor ("Memory Motor")

18 Our team would like to thank Professor Ewald Fuchs 2007 IFEC Committee IEEE and PELS Acknowledgements Boulder Electric Motor Company Hybrids Plus Boundless Corporation Bernard Gordon Prize CU Power Lab (CoPEC) CU Engineering Excellence Fund and UROP Indian Institute of Technology Department of Electrical Engineering University of Colorado at Boulder Department of Electrical and Computer Engineering MPC Products Corp. for support of this project.