OSU Research Program In Mechatronic Systems. Ali Keyhani Mechatronics Laboratory Dept. of Electrical Engineering The Ohio State University

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1 OSU Research Program In Mechatronic Systems Ali Keyhani Mechatronics Laboratory Dept. of Electrical Engineering The Ohio State University 1

2 Acknowledgement Ph.D. Students Nanda Marwali Wenzhe Lu Min Dai Jin-woo Jung 2

3 Outline Graduate Program in Mechatronics New Initiative Fuel cell energy conversion systems By Wire Cars Undergoing research 3

4 Control of Variable-Speed Drives Electro-Hydraulic Actuators Energy Storage Systems Electric machines Mechanical Engineering Mechatronics Electrical Engineering Smart Structures Electric Vehicles Automotive Powertrain Electronic Systems Systems Power Electronics System Modeling, Identification and Computer Electro-Mechanical Diagnosis Engineering Actuators Hybrid-Electric Vehicles Energy Systems Embedded DSP and Microcontroller Systems T1 + T3 T5 Vt1 - Vdc T2 a + T4 b T6 c M Vt2-4

5 Mechatronics in Automotive Systems Embedded DSP/microcontrollers Active noise cancellation Electric motor drive control in hybrid electric car IC Engine control Adaptive comfort control : heat, ventilatiion, air condition Thermal management system control Active suspension control Power steering and traction control 5

6 Voltages Feedback signals measurements DSP System for Control of Electric Motor Drives DSP board Currents Power Converter & Drive Circuit Speed Electric motor 6

7 What is a fuel cell? A fuel cell is an electrochemical energy conversion device that converts hydrogen and oxygen into electricity and heat Potential to truly revolutionize power generation by virtue of their inherently clean, efficient, and reliable service 7

8 How does a fuel cell work? Produce power electrochemically by simultaneously passing a hydrogen-rich gas over an anode and air over a cathode. By introducing an electrolyte in between the two, an exchange of electrical charges occurs -- ions. Hydrogen reacts with oxygen, causes one or the other stream to become charged, or ionized. The flow of ions through the electrolyte induces an electric current in an external circuit or load. 8

9 How does a fuel cell work? 9

10 Our role in fuel cell applications-energy Conversions for Distributed generation With or without utility interfacing Power supplies for critical loads Automotive Zero-emission vehicles Manpower Training and Research 10

11 Typical System Requirements Output power capacity, nominal and overload Output voltage and frequency Steady state and transient Robustness to load disturbances Protections Utility interaction and parallel operation Efficiency EMI Automotive Requirements: Cost, Volume, and Weight 11

12 FC Energy Conversion System Development Issues (1) System configuration and auxiliary source DC Bus Fuel Cell DC/DC converter DC/AC inverter Load Battery Measurement/control DC/DC converter Controller 12

13 FC Energy Conversion System Development Issues (2) Fuel cell modeling The electrochemical process can be modeled for simulation or FC simulator development purpose. An example of a V-I curve of a PEM FC model Output Voltage (V) PEM Output Voltage vs. Current for Different Fuel Flow Rates Output Current (A) 100% Flow 75% Flow 50% Flow 25% Flow 13

14 FC Energy Conversion System Development Issues (3) Internal power flow control DC/DC converter operated in parallel Power flows FC load and auxiliary source FC and auxiliary source load Load sharing with transient requirements 14

15 FC Energy Conversion System Development Issues (4) DC/AC conversion 3-ph or single phase Voltage regulation (steady state) THD Transient response Overload protection Robustness to various disturbances 15

16 FC Energy Conversion System Development Issues (5) Utility interfacing Load sharing issue Possible solutions Master/slave Droop method Line impedance issues Communication with the FC and the closed-loop performance 16

17 FC Energy Conversion System Development Issues (6) Specifications of a 5kW system as an example Manufacturing cost: <US$40/kW Package size: convenient shape, volume < 88.5dm 3 Package weight: < 15kg Output capacity (nominal) : 5kW@displacement factor 0.7 Output capacity (overload): 10kW overload for 1 minute (5kW from FC, 5kW from battery)@d.f

18 FC Energy Conversion System Development Issues (7) Specifications of a 5kW system as an example Current limit: 110% of max. overload condition Output voltage: single phase 120V/240V nominal Output frequency: 60Hz±0.1Hz Output harmonic quality: THD < 5% Output voltage regulation quality: within ±6% over the full allowed line voltage and temperature range, from no load to full load 18

19 FC Energy Conversion System Development Issues (8) Specifications of a 5kW system as an example FC source: 22-41VDC, 29VDC nom., 275A max Max. input current ripple: 3% rms of rated current Battery auxiliary power: 48VDC +10% -20% with nominal rating of 500 Wh, 5kW peak for 1 min. Overall energy efficiency: > 94% for resistive load Protection: Overcurrent, overvoltage, short circuit EMI: Per FCC 18 Class A 19

20 FC Energy Conversion System Development Issues (9) Specifications of a 5kW system as an example Grid interaction: None Communication interface: RS232 Environment: indoor and outdoor in domestic appl. Storage temperature: -20 ~ 85 C Operating ambient temperature: 0~40 C Enclosure type: NEMA 1 Cooling: Air cooled 20

21 Undergoing Research (1) Single 3-ph inverter control system Low steady state error Low harmonics (THD) Fast transient Robustness to load disturbances Parallel operation of two 3-ph inverters Load sharing with phase angle droop technique Passive load only 21

22 Undergoing Research (2) Parallel operation of two 3-ph inverters With utility interfacing Testbed under construction DC/DC converters and internal power flow control FC simulator and closed-loop system analysis 22

23 OSU Research Test Bed Circuit Breaker M1 Measurements: A: 2C, 2V; A? 2C, 2V; B: 1C, 1V; B? 1C, 1V; C: 2C, 2V; C? 2C, 2V; D: 3C, 3V; D? 3C, 3V; E: 3C, 3V; E? 3C, 3V; Total: 22C + 22V = 44 Channels Unit A B C 1 D E Circuit Breaker M2 Contacto r M2 Contacto r L1 208V Main Circui t Breake r L1 240V Main Load E Circuit Breaker M3 Unit A B C 2 D Circuit Breaker M4 Contacto r Contacto M4 r L2 Circui t Breake r L2 240V Main Load 23

24 2. Five Different Configurations for DES Power Converters supplying power in a Stand-alone mode or feeding it back to the utility mains Power Converter Sensors Utility Mains Microturbine 3 φ AC 240/480 V 50 or 60 Hz Controller PWM V, I, f Transformer Communications Sensors Loads (Linear/Nonlinear) Fuel Cell Controller PWM V, I, f Communications Distributed Control Center 24

25 Control of a Boost Inverter Using Z-source for Fuel Cell Systems Z-source Inverter Configuration Z-source Inverter: a DC source, a diode, L-C impedance, a DC/AC inverter, L/C filter, and a load Diode: to prevent a reverse current that can damage the fuel cell Z-source D L 1 S1 S3 S5 L f C 1 C 2 Fuel Cell (V in ) S4 S6 S2 C f 3-phase load L 2 Fig. 1 Total system configuration with Z-source inverter. 25

26 Circuit analysis of Z-source Inverter Two Operation Modes: Non-shoot-through switching mode: basic space vectors (V 0, V 1, V 2, V 3, V 4, V 5, V 6, V 7 ) Shoot-through switching mode: both switches in a leg are simultaneously turned-on (a) In the shoot-through zero vectors (b) In the non-shoot-through switching vectors. Fig. 2 Equivalent circuit of Z-source inverter. 26

27 Entire Control-loop Structure Fig. 3 Total control system block diagram. where, DSMC is the discrete-time sliding mode controller, PI is the discrete-time proportional-integral controller, SVPWM is a three-phase space vector pulse width modulation, I cmd,,qd is the current command signal, I * iqd is the limited current command, V * iqd is the voltage command, and V i is the true inverter output voltage. 5 27

28 By-Wire Cars Application of Embedded Systems to Brake-By-Wire Application of Embedded Systems to Steer-By-Wire 28

29 By-Wire Cars Replacing a car s hydraulic system with wires, microcontrollers (DSP s) and computers Using electric motors (PM, IM, SRM) for actuators No hydraulic backup to the electronic system Having been used successfully for several years in aircraft 29

30 Goal of By-Wire Cars The goal of by-wire is to make the average driver as skilled as a professional test course driver in bringing the vehicle back to a safe and stable condition from an unsafe one. 30

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32 Advantages Basic functionality without complex mechanical or hydraulic parts Better safety, stability, and handling Better fuel economy Cost reduction by easier construction and package 32

33 Challenges How drivers will react to the wires, computers, and microcontrollers (DSP s) No industry-wide standard for by-wire system Cooperation of by-wire parts Electric power storage and supply 33

34 Brake-By-Wire Brake-by-wire does everything: Braking ABS Antilock brake system Brake power assisting Vehicle stability enhancement control Parking brake control Tunable pedal feeling 34

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36 Application of Embedded System to Brake-By-Wire Plug-in modules for Brake-By-Wire 36

37 Application of Embedded System to Brake-By-Wire EMB: Electromechanical Brake Actuators BBWM: Brake-By-Wire Manager 37

38 Application of Embedded System to Brake-By-Wire System structure Fd DSP based Controller V Motor T Gear and Screw Caliper Fcl Position Sensor Force Sensor 38

39 Application of Embedded System to Brake-By-Wire Electromechanically actuated disk brake by ITT Automotive 39

40 Application of Embedded System to Brake-By-Wire Control of brake-by-wire system Four-quadrant operation of servo-motor Desired clamping force response Torque ripple minimization Elimination of rotor position sensor Elimination of clamping force sensor Fail-safe operation 40

41 Steer-By-Wire Not just electrically assisted power steering Steer-by-wire comes in two flavors: Front steer Rear wheels Cars with steer-by-wire may not even have a driver s wheel 41

42 Application of Embedded System to Steer-By-Wire Only wires may relay signals from a car s steering wheel to its front wheels in a front steer-by-wire system. And an electrically actuated motor, not a mechanical link with the steering wheel, turns the front wheel. 42

43 Application of Embedded System to Steer-By-Wire Rear steer-by-wire tightens the turning radius and increases vehicle stability. With rear steer-by-wire, the rear wheels don t just follow the lead of front wheels. In contrast, they turn in the opposite direction to the front wheels during tight turns, providing any size car with the agility of a small car. 43

44 OSU Sensorless control of induction motor using variable frequency models for propulsion Sensorless control of induction motor for power steering and steer-by-wire Four-quadrant sensorless control of switched reluctance motor for brake-bywire system 44

45 OSU Sensorless torque control of IM 45

46 OSU Adaptive sliding mode observer for IM 46

47 OSU Experimental setup 47

48 Hardware in the loop TestBed Windows 95/NT program written in C++ Object oriented design Controller Object Circuits Object Timer Object Waveform Analyzer Scope Objects Other GUI Objects User Interface Object -Executes DSP native codes - Communicates with simulator program on PC -Runs simulation program including : a. Circuit simulations b. FPGA Timings c. User Interface -Controls the simulation timing Liebert's TMS320C50 Evaluation Board Host PC DSP board for Native Code Implementation 48

49 OSU Experimental setup 49

50 OSU Sliding mode observer based controller for SRM (switched reluctance motor) DSP DSP based Controller V SRM SRM model + _ I Î Observer θˆ ωˆ 50

51 OSU Clamping force control for brake-by-wire Four-quadrant operation Force control and torque ripple minimization Sensorless operation (no rotor position sensors) V,I T,θ DSP DSP based Power Controller SRM Inverter Brake θ, ω Observer F cmd F 51

52 OSU Experimental setup for brake-by-wire 52

53 OSU Experimental setup for brake-by-wire 53

54 Conclusions Tough Economic Conditions Support form Industry has gone down Currently, We have three NSF Grants We are teaming up with National Fuel Cell Research Center in California for new initiative in Design, Modeling and Control of Fuel Cells An Industry-University NSF Proposal. We appreciate your support. 54