WPT: From W/cm 2 Harvesting to kw Capacitive Vehicle Powering

Transcription

1 WPT: From W/cm 2 Harvesting to kw Capacitive Vehicle Powering Department of Electrical, Computer and Energy Engineering Prof. Zoya Popovic University of Colorado Boulder Thanks to my PE colleagues: Prof. Dragan Maksimovic Prof. Khurram Afridi Prof. Bob Erickson Prof. Hanh-Phuc Le Coleman Institute for Cognitive Disabilities

2 Types of Wireless Power Transfer Reactive near-field coupling Higher power levels Sensitive to alignment Far-field directive High power levels Large antennas for narrow beams Efficiency important Far-field flooding Non-directive Low power Small duty cycle Efficiency not as critical Multi-mode Medium power Multiple devices Shielded Efficiency important 2

3 Types we are not talking about today 1975 Goldstone, California: Brown and his team were able to recover 30 kw DC output at 2.5GHz over a 1.6km distance from a transmitted power of 450kW Multi-moded cavity with mode mixing for efficient powering of multiple devices simultaneously S. Korhummel, A. Rosen, Z. Popovic, Over-moded cavity for multiple-electronic device wireless charging, IEEE Trans. Microwave Theory Techn., Vol. 62, Apr

4 Histiry: Wireless Power Transfer Nikola Tesla ( ) 1899, Colorado Springs: transmitted 100 million volts of highfrequency electric power wirelessly over a distance of 26 miles, lit up a bank of 200 light bulbs and ran one electric motor. Nikola Tesla s United States Patent No.685,954, November 5, 1901 Method for utilizing effects transmitted through natural media Claim 11: utilizing effects or disturbances transmitted through the natural media from a distant source, which consists in storing in a condenser electrical energy derived from an independent source, and using, for periods of time predetermined as to succession and duration, the accumulated energy so obtained to operate a receiving device. 4

5 Power Extremes Harvesting of far-field microwave power with power densities in the W/cm 2 range sensors Near-field wireless charging in the kw range EVs, industrial 5

6 Low-Power Harvesting RF power reception (rectifier-antenna) Transmitter(s) in far field r=2d 2 / Distributed power receivers, non-directive low-power transmitters Power management circuit optimally charges storage element Integration of power management and RF power receiver critical for low-power applications Sensor platform Strain gauge Temperature sensor Accelerometer Data Wireless transmitter Power Management Circuit Storage Energy buffer + Intelligence (microcontroller) Optimal DC power delivery Controls DC power Data transmission ISM (~2.45GHz) RF power receiver (rectenna) On-demand RF power Radio-wave Illumination from far field Known or unkown transmitter 1 T Transmitter 2 6

7 Some Low-Duty Cycle Applications Low duty cycle patient health monitoring sensors Wireless demo unit requires less than 5 W average power, transmits ~100 bits every 5 seconds, 10 m range Integrated with a 6 cm x 6 cm, dual linear polarized, 2.45 GHz rectenna 400 mah 4 V thin film battery D. Costinett, E. Falkenstein, R. Zane, Z. Popovic, Far-field RF-powered variable duty cycle wireless sensor platform, IEEE Trans. Circuits and Systems,, pp , Vol. 58, Dec Aircraft wing corrosion monitoring Wireless powered sensors offer fast inspection, less downtime, and labor cost reduction. X. Zhao, T. Qian, G. Mei, C. Kwan, R. Zane, C. Walsh, T. Paing, Z. Popovic, Active health monitoring of an aircraft wing with an embedded piezoelectric sensor/actuator network: II. Wireless approaches, Smart Materials and Structures, 16(2007), pp , June Sensors for green buildings Monitoring mold, HVAC flow, occupancy, light level, etc. 7

8 Step 1 for RF harvesting: understand power need and RF environment Power is collected continuously at low levels Power is used when there is enough stored Suitable for low duty cycle applications Low-power timing control required Normalized CDMA base station output power for three different cell locations over a 3-week period Z. Popovic, "Cut the Cord: Low-Power Far-Field Wireless Powering," Microwave Magazine, IEEE, vol.14, no.2, pp.55,62, March-April

9 Power Receiver Design Characterize rectifier element Design antenna / matching DC Output P DC 75mm ~ Sweeper Power meter P RF Tuner Rectifying element 60mm 39.6mm 1 7 Rectifying element impedance nonlinear Low power: Schottky diode Perform diode source pull Vary DC load +j0.2 +j j j j j j2.0 +j j j SMA Connector +j0.2 -j0.2 +j j j j j j2.0 +j j5.0 Falkenstein, E.; Roberg, M.; Popovic, Z.;, Low-Power Wireless Power Delivery, Microwave Theory and Techniques, IEEE Transactions on, vol.60, no.7, pp , July

10 Power Receiver Design Characterize rectenna Design Power Management Source model Boost converter Energy storage I in i L R g + L + R BAT + V g V DC C in C o V B - - VBAT V B V B HF osc LF Osc. k, T lf HF EN HF Osc. t 1, T hf Timing control circuit Battery Boost Power Stage MSP430 μcontroller nrf24l01+ Transciever Rectenna Connector Chip Antenna Printed Folded Dipole Antenna Z. Popovic, E. Falkenstein, D. Constinett, R. Zane, Low-power far-field wireless powering for wireless sensors, Proceedings of the IEEE, Special Issue on Wireless Powering, Vol.101, No. 6, pp , June

11 Example Rectennas Frequen Source-pull Input DC output RF-DC cy power power efficiency 915 MHz dbm dbm 40.7 % 2.45 GHz dbm dbm 56.2 % - Dual linear polarization, 2.1GHz, 1 W/cm 2 - Dual frequency - 2.4GHz and 915MHz - 1 W/cm 2 - printed Yagi - capacitor and diode - <2gr mass Korhummel, S.; Kuester, D.G.; Popovic, Z., "A harmonically-terminated two-gram low-power rectenna on a flexible substrate," Wireless Power Transfer (WPT), 2013 IEEE, vol., no., pp.119,122, May

12 Example: harvesting altimeter sidelobes J. Estrada, I. Ramos, A. Narayan, A. Keith and Z. Popovic, "RF energy harvester in the proximity of an aircraft radar altimeter," 2016 IEEE Wireless Power Transfer Conference (WPTC), Aveiro, 2016 Frequency Range GHz; Power 10 mw to 500 mw Antenna gain Power density μw/cm 30 cm Power transfer rate for the SMS7630 rectifier prototype 12

13 Large-Area Array Harvesters In an array, each antenna element has its own rectenna and incident phase is not relevant since the DC is combined DC combining can be reconfigurable A. Dolgov, R. Zane, Z. Popovic, Power Management System for Online Low Power RF Energy Zoya University of Colorado, Boulder, 2018 Harvesting Optimization, IEEE Transactions on Circuits and Systems -I, pp ,

14 Array Harvesters Wirelessly charged micro- UAV using farfield microwave energy (5.9 GHz) Charging circuit Rectenna Broadband 2-18GHz multi-tone harvesting (wall-paper) Microwave Prize, 2004 Basta, N.P.; Falkenstein, E.A.; Popovic, Z., "Bowtie rectenna arrays," IEEE WPTC 2015, May 2015 Zoya J.A. Hagerty, Popovic, F. University Helmbrecht, of W. Colorado, McCalpin, Boulder, R. Zane, Z Popovic, Recycling ambient microwave energy with broadband antenna arrays, IEEE Trans. Microwave Theory and Techn., pp , March

15 Extremes Harvesting of far-field microwave power with power densities in the W/cm 2 range sensors Near-field wireless charging in the kw range industrial and EVs 15

16 Inductive Powering: Industrial WPT Curtesy: Prof. Alessandra Costanzo, Univ. of Bologna, Italy Dr. Riccardo Trevisan, IMA, Italy Output voltage = 230 Vac Power rating = 1.3 kw Air gap = 0.6 mm Temperature = C Efficiency > 90 % Tea bag packaging machine R. Trevisan and A. Costanzo, A 1-kW contactless energy transfer system based on a rotary transformer for sealing rollers, IEEE Trans. Ind. Electron., vol. 61, pp , Nov 2014.

17 Inductive WPT and Wireless Data Simultaneous IWPT and data transfer at: 13.56MHz, capacitive coupling 868 MHz, split-ring resonators f = 37kHz, P = 1.3 kw Measured efficiency 96% - Winding loss: 21 W - Core loss: 8W R. Trevisan and A. Costanzo, "A UHF Near-Field Link for Passive Sensing in Industrial Wireless Power Transfer Systems," IEEE Trans. Microwave Theory Techn., vol. 64, pp , May 2016.

18 High-Power Near-Field CWPT Penetration of electric vehicles (EVs) remains low due to limitations in battery technology: Limited range due to limited energy density Long charging times High cost Dynamic wireless power transfer (WPT) can change this situation by drastically reducing the need for batteries in EVs Thousands U.S. vehicle sales in 2016 Total: million EV: 0.13 million Battery and Plug-in Hybrid Electric Vehicles in US

19 Current: Inductive and Capacitive WPT Road Side Vehicle Side Road Side Vehicle Side V IN High Frequency Inverter Current Gain and Compensation Network Voltage Gain and Compensation Network High Frequency Rectifier V OUT V IN High Frequency Inverter Voltage Gain and Compensation Network Current Gain and Compensation Network High Frequency Rectifier V OUT Current approaches to stationary and dynamic WPT for EVs: inductive coupling Inductive systems require ferrite cores for magnetic flux guidance and shielding Expensive, fragile, difficult to embed in roadway Relatively low frequencies to limit ferrite losses large and heavy 22 khz 20 kw/m 2 90% 0.9 kw/kg Source: ORNL Source: KAIST Capacitive WPT systems do not have ferrites and can be: Less expensive More efficient Smaller, lighter Easier to embed in roadway Generally used for low power applications Capacitive charging of EVs through tires (low efficiency due to carbon black filler, low power transfer due to limited area) Source: Toyohashi University of Technology 17

20 CWPT: Safety Concerns ICNIRP Electric Field Safety Limits Our Approach: Near-Field Phased Array Pacemaker safe everywhere ICNIRP dominates 6.78 MHz at 2) Living Object Detection 18

21 CWPT Module Matching Networks Four rectangular plates, f = 6.78 MHz (ISM band) Input and output L-Section symmetric matching networks Two-Stage Matching Network Analytical approach Q L = 400 Q L = 300 Q L = 200 Q L = 100 Predicted Efficiency Measured Efficiency of Prototype Numerical approach H-Bridge topology, 650 V, 15 A GaN 19

22 Single-Module Measurements Air gap: 12 cm Operating frequency: 6.78 MHz Output Power: 1216 W Power Transfer Density: 51.6 kw/m 2 Efficiency: 74.7% Coupler Power to Weight Ratio: 11.1 kw/kg Output Power: 589 W Power Transfer Density: 19.6 kw/m 2 Efficiency: 88.2% Coupler Power to Weight Ratio: 4.3 kw/kg Coupling Plates (12.25 cm diameter) Inverter Coupling Plates (12.25 cm x cm) 20

23 Multi-Module Phased Array Energy transfer zone 1 module Safety zone Energy transfer zone 8 modules Safety zone 21

24 Scaled Multi-Module Measurements Measurements Simulations ETS Lindgren HI-6005 E-field probe 100 khz 6 GHz V/m 22

25 Measurement Results 7 MHz 14 MHz 29 MHz J. Estrada, S. Sinha, B. Regensburger, K.K. Afridi and Z. Popovic, Capacitive Wireless Powering for Electric Vehicles with Near-Field Phased Arrays, Proceedings of the European Microwave Conference, Nuremburg, Germany, October E-field measurements and simulations: - As a function of distance along x axis - For different relative phases - Three ISM-bands (6.78, and MHz) 23

26 Two-Module Capacitive WPT System Vehicle Chassis Ground Coupling plates (12.25 cm x cm) Air gap: 12 cm Operating frequency: 6.78 MHz Output Power: 1108 W Power Transfer Density: 19 kw/m 2 Efficiency: 90% Coupler Power to Weight Ratio: 4.1 kw/kg 1000-W Two-module phased W Single-module 1000-W Two-module phased 180 ICNIRP Limit 24

27 References, CWPT and other 1. A. Kumar, S. Pervaiz, C.K. Chang, S. Korhummel, Z. Popovic and K.K. Afridi, "Investigation of Power Transfer Density Enhancement in Large Air-Gap Capacitive Wireless Power Transfer Systems," Proceedings of the IEEE Wireless Power Transfer Conference (WPTC), Boulder, CO, May F. Lu, H. Zhang, H. Hofmann and C. Mi, A Double-Sided LCLC-Compensated Capacitive Power Transfer System for Electric Vehicle Charging, IEEE Transactions on Power Electronics, vol. 30, no. 11, pp , November H. Zhang, F. Lu, H. Hofmann, W. Liu and C.C. Mi, "A Four-Plate Compact Capacitive Coupler Design and LCL-Compensated Topology for Capacitive Power Transfer in Electric Vehicle Charging Application," IEEE Transactions on Power Electronics, vol. 31, no. 12, pp , December I. Ramos, K.K. Afridi, J. A. Estrada and Z. Popović, "Near-Field Capacitive Wireless Power Transfer Array with External Field Cancellation," Proceedings of the IEEE Wireless Power Transfer Conference (WPTC), Aveiro, Portugal, May S. Sinha, A. Kumar, S. Pervaiz, B. Regensburger and K.K. Afridi, "Design of Efficient Matching Networks for Capacitive Wireless Power Transfer Systems," Proceedings of the IEEE Workshop on Control and Modeling for Power Electronics (COMPEL), Trondheim, Norway, June K. Doubleday, A. Kumar, S. Sinha, B. Regensburger, S. Pervaiz and K.K. Afridi, "Design Tradeoffs in a Multi-Modular Capacitive Wireless Power Transfer System," Proceedings of the IEEE PELS Workshop on Emerging Technologies: Wireless Power Transfer (WoW), Knoxville, TN, October B. Regensburger, A. Kumar, S. Sinha, K. Doubleday, S. Pervaiz, Z. Popović, K.K. Afridi, High-Performance Large Air-Gap Capacitive Wireless Power Transfer System for Electric Vehicle Charging, Proceedings of the IEEE Transportation Electrification Conference and Expo (ITEC), Chicago, IL, June K. Doubleday, A. Kumar, B. Regensburger, S. Pervaiz, S. Sinha, Z. Popovic and K.K. Afridi, Multi-Objective Optimization of Capacitive Wireless Power Transfer Systems for Electric Vehicle Charging, Proceedings of the IEEE Workshop on Control and Modeling for Power Electronics (COMPEL), Stanford, CA, July S. Sinha, B. Regensburger, K. Doubleday, A. Kumar, S. Pervaiz and K.K. Afridi, High-Power-Transfer-Density Capacitive Wireless Power Transfer System for Electric Vehicle Charging, Proceedings of the IEEE Energy Conversion Congress and Exposition (ECCE), Cincinnati, OH, October S. Sinha, A. Kumar, B. Regensburger, and K.K. Afridi, A Very-High-Power-Transfer-Density GaN-Based Capacitive Wireless Power Transfer System, Proceedings of the IEEE Workshop on Wide Bandgap Power Devices and Applications (WiPDA), Albuquerque, NM, October/November T. Paing, E. A. Falkenstein, R. Zane and Z. Popovic, Custom IC for Ultralow Power RF Energy Scavenging, IEEE Transactions on Power Electronics, vol. 26, no. 6, pp , June Ramos, I.; Ruiz Lavin, M.N.; Garcia, J.A.; Maksimovic, D.; Popovic, Z., "GaN Microwave DC DC Converters," in Microwave Theory and Techniques, IEEE Transactions on, vol.63, no.12, pp , Dec I. Ramos and Z. Popović, "A fully monolithically integrated 4.6 GHz DC-DC converter," 2016 IEEE MTT-S International Microwave Symposium (IMS), San Francisco, CA, 2016, pp. 1-4.

28 Summary and Conclusions Wireless far-field microwave power harvesting at low-power density levels ( W/cm 2 ) practical for low duty-cycle applications Broadband harvesting and/or dedicated compliant transmitters needed to ensure sufficient power High-power near-field capacitive wireless power transfer shows good efficiency at high frequencies (several MHz) Safety limits can be met with array architectures

29 Thank you!