Md. Kaisar Rashid Khan

1. Md. Kaisar Rashid Khan Ph. D (EE) Candidate University of Central Florida

2. Believe in • Professionalism • Innovation • Integrity • Honesty • Patience

3. EDUCATION • Ph. D, (EE) Expected date of Graduation Fall 2007, University of Central Florida • MSEE, The University of Texas at El Paso • M. Eng, Bangladesh University of Engineering and Technology, Dhaka. • B. Sc. Eng., Bangladesh Institute of Technology, Rajshahi

4. Related Publication • Kaisar R Khan, Q. Ahsan and M. R Bhuiyan, “Expected Energy Production Cost of Two Area interconnected Systems with Jointly Owned Units” Electric Power System Research journal (Elseiver), April 2004. • Kaisar R Khan, Q. Ahsan and M. R Bhuiyan, “Expected Energy Generation of Two Geographically Isolated Area System with Jointly Owned Units”, Presented third International Conference on Renewable Energy for Sustainable Development, October 2003,Dhaka, Bangladesh

5. Related Graduate Courses • DSP • Power Electronics • Machine Design • Power System Planning • Power System Transient • Power System Stability • VLSI • Advance Semiconductor Devices

6. Research Focus: Power Electronics and electromagnetic modeling Major Advisor: Dr. Thomas Wu Dept. of ECE, UCF

7. Magnetic Circuit Analysis of PMSM using FEM

8. Geometric Model

9. Flux line distribution of the proposed motor at (a)150A (b) 650A (b) (a)

10. Flux Density Profile of the Proposed Motor (a)150A (b) 650A

11. Torque Profile

12. Supper High Speed PMSM Kaisar Khan, Dr. Liping Zheng, Dr. Thomas Wu and Dr. L. Chow University of Central Florida

13. Rotor and its components Winding using multi-strand Litz-wire The specifications of the axial flux PMSM Winding with a total of 84 turns Axial view of the axial flux PMSM

14. Winding Modeling

15. Flux & Back EMF

16. Torque Simulation • Constant torque is required. Torque ripple should be as small as possible. • Virtual Work • Field oriented current applied. • Torque constant: 0.004 N.m /A

17. Housing and Cooling

18. Dynamic Torque and Back EMF

19. Some Parameters • Phase resistance: 0.06 Ω • Phase inductance: 1.6 H @ f=1 KHz 2.0 H @ f=100 Hz • Rotor inertia: 3.65210-5 Kgm2 . • Back EMF constant: 0.138 V/Krpm • Maximum speed: 100,000 rpm • Nominal speed: 50,000 rpm

20. Load Test Method • Measuring input phase to phase voltage (Vbc), and phase current (Ia). • Tested efficiency: • 60% @ 50,000 rpm with 100 W output.

21. Material Considerations • Permanent magnet • Nd-Fe-B (neodymium -iron-boron ): the highest energy density, does well above 135 K. However, it undergoes a spin reorientation below 135 K. • Sm-Co (samarium cobalt): does quite well at both cryogenic temperature and higher temperature. • Winding • Multi-strand Litz-wire to reduce eddy current loss. • Heavy insulation to withstand at 77 K. • Stator • Laminated low loss silicon steel: 0.005” thickness.

22. PMSM Loss Sources • Stator core loss • Eddy current, hysteresis and excess loss • Rotor loss • Eddy current loss • Copper loss • I2R loss • Eddy current loss due to skin effect and proximity effect • Mechanical loss • Bearing loss and windage loss

23. Electrical Resistivity of Cu  1/10

24. Copper Loss - Eddy Current • Eddy current loss per unit conductor volume is: round wire rectangular section conductor where Bp is the peak flux density,  is the electrical angular frequency, d is the diameter, and  is the resistivity.

25. Eddy Current – Solid Wire I = 582 A Solid Copper @ 77 K, diameter=1.5 mm

26. Eddy Current – Litz-wire I = 37 A 75 strands @ AWG 36 (0.125 mm)

27. Load Test Results (II)

28. Motor Controller Kaisar Khan, Limei Zhao, Thomas Wu and L. Chow University of Central Florida

29. Motor Drive Simplified motor test circuitry Current and voltage waveforms @ 60,000 rpm space vector PWM drive and low pass filter

30. The Controller Configuration Hardware TMS320LF2407A

31. Controller Schematic

32. Prototype under testing

34. MOSFET MOSFET equivalent circuit in high frequency • Cgd :Gate-to-drain capacitance (Miller capacitance ) • Non-linear • Affected by voltage • Gate charge Q: the lower, the better • For low-power, high-frequency applications • Up to a few kilowatts • Heatsink • 2 to 5 times larger than expected • Power ratings • Should be derated by 30 ~ 50% to ensure long-term reliability Safe Operating Area (SOA) • Fairchild FDP047AN08A0 • 75 V,80 A,4.7 mΩ, and 92 nC • 2-4 MOSFET paralleling prototype

35. Drive Chip IR2110 I_drive: up to 2A sink and 2A source Bootstrap circuit t_rr < 100ns Qg=Gate charge of high side FET, VLS= Voltage drop across the low side FET or load f=frequency of operation , Vf= Forward voltage drop across the bootstrap diode tw=pulse width of level shift currents , Icbs(leak)=Bootstrap capacitor leakage current Ilson/Ilsoff=level shift currents required to switch on or off

36. High Current Design (I) • Electronic components are more sensitive to temperature extremes. • Semiconductor long-term reliability is directly affected by operating temperatures. • The maximum junction temperature is the critical design point for motor control power stages. • Reliability research suggests that for each 10°C rise in junction temperature, the long-term reliability is decreased by about 50 percent. • Thermally effective packages have a much lower junction-to-case thermal resistance. • 3,4 or 5 oz. copper conductors and planes help spread heat throughout the PCB making the module temperature more homogeneous and reducing hot spots.

37. Loss Calculation • Inverter takes almost all loss in controller • MOSFET loss is main concern 95% in theory 94% of total switching loss Up side: 0.3% of total switching loss 3.7% of total switching loss Low side: Only 15% of low side total loss Iout=65 A, RDS(ON)=2.35 mΩ, V=11.4 V,Crss=480 pF, Fsw=50 KHz, Igate=1 A MOSFET conduction loss is main loss for < 1 MHz

38. Prototype of HW of Controller • Different controllers for different power rating motor systems • Same concept block • Different hardware: topology,components, schematics, and layout • Different software: parameters, optimized code • Two print circuit boards (PCB): • The controller board: low voltage components and trace • The power stage board: the high-voltage components and trace • The power stage prototype need not change too much, but the controller board may change significantly. Making them into two different boards can make the optimization much easier.

39. TI TMS320LF2407A • 16-bit fixed-point DSP • Specifically designed for the Digital Motor Control TI TMS320LF2407A Evaluation Board

40. Software Configuration Optimal V/f control scheme helps to set boost voltage, V/f slope, FL, FH

41. Significant Results • Efficiency as high as 90%. • No load maximum speed 120K (RPM) • Achieve maximum speed of 60K with load. • An axial flux pancake PMSM is presented for the first time. (Dr. Liping’s sole contribution)

42. Power System Planning

43. Expected Energy Production Cost of Two Area Interconnected Systems with Jointly Owned Units

44. A new probabilistic methodology has been developed to evaluate the expected energy production cost of two area-interconnected systems with a jointly owned unit as well as a conventional unit.

45. Expected Energy Generation and Inter Operator Export-Import

46. Effect of Tie-line Capacity Increase

47. Significant Results • The proposed method keeps track of the export/import of energy by the individual unit. • The inclusion of a JOU in the system reduces the global capacity transaction at a higher tie line capacity; however, the higher capacity transaction is observed at lower tie line capacities.

48. An Important Case Study: Implementing the Developed Probabilistic Model Power System of Bangladesh

49. Global Expected Energy Generation

50. Effect of Tie-line Capacity Change