Time Reversed Electromagnetic Wave Propagation as a Novel Method of Wireless Power Transfer

Transcription

1 Time Reversed Electromagnetic Wave Propagation as a Novel Method of Wireless Power Transfer Frank Cangialosi, Tyler Grover, Patrick Healey, Tim Furman, Andrew Simon, Steven M. Anlage 1

2 Current State of Long-Range WPT Ubiquitous WPT requires greater range than provided by near-field technologies Microwave Beaming

3 Current State of Long-Range WPT Ubiquitous WPT requires greater range than provided by near-field technologies Microwave Beaming Precise Alignment Obstructions

4 Current State of Long-Range WPT Ubiquitous WPT requires greater range than provided by near-field technologies Microwave Beaming Precise Alignment Obstructions

5 Current State of Long-Range WPT Ubiquitous WPT requires greater range than provided by near-field technologies Microwave Beaming Precise Alignment Safety Hazard Obstructions

6 1. Time Forward Step Target requests power, source records sona Time Reversal A signal-focusing technique Target Device T S Voltage (mv) Power Source (Enclosed cavity with reflecting walls)

7 1. Time Forward Step Target requests power, source records sona Gaussian Pulse (5 ns) T Time Reversal A signal-focusing technique Target Device S Voltage (mv) Power Source (Enclosed cavity with reflecting walls) Sona"

8 Time Reversal A signal-focusing technique 1. Time Forward Step Target requests power, source records sona 2. Time Reverse Step Source reverses and broadcasts, sona reconstructs on target Time(µs) Target Device T S Voltage (mv) Power Source (Enclosed cavity with reflecting walls) Sona"

9 Time Reversal A signal-focusing technique 1. Time Forward Step 2. Time Reverse Step Target requests power, source records sona Source reverses and broadcasts, sona reconstructs on target Target Device T Time(µs) Sona" 51 Voltage (mv) (Enclosed cavity S Power Source with reflecting walls)

10 Time Reversal A signal-focusing technique 1. Time Forward Step 2. Time Reverse Step Target requests power, source records sona Source reverses and broadcasts, sona reconstructs on target Target Device T Reconstruction Time(µs) pulse Sona" 51 Voltage (mv) (Enclosed cavity S Power Source with reflecting walls)

11 Time Reversal A signal-focusing technique 1. Time Forward Step 2. Time Reverse Step Target requests power, source records sona Source reverses and broadcasts, sona reconstructs on target Target Device T Reconstruction Time(µs) pulse Sona" (Enclosed cavity 51 Voltage (mv) Good for rectification S Power Source with reflecting walls)

12 Time Reversal for WPT Requires Provides 1 Spatial reciprocity of the wave equation 1 Range (not limited to free space drop-off) 2 Reflective surfaces 2 Resilience to obstructions 3 Ray-chaotic environment 3 Power concentrated at any given location 5

13 Experimental Setup Power Source (5Ghz, 3dBm) Scattering panels ensure ray chaos Device (on MikroMove) +35 (mm) -35 Wave Generation (TX) Wave Analysis (RX) PSG AWG MATLAB Oscilloscope 6

14 Spatial Profiling of Reconstruction +35 Target: mm -35 Constant Velocity.2 mm/s 7

15 Spatial Profiling of Reconstruction +35 Target: mm -35 Constant Velocity.2 mm/s 7

16 Spatial Profiling of Reconstruction +35 Target: mm -35 Constant Velocity.2 mm/s 7

17 Spatial Profiling of Reconstruction +35 Target: mm -35 Constant Velocity.2 mm/s 7

18 Spatial Profiling of Reconstruction x + c V (x) =a sinc b + d V (x) x 8

19 Spatial Profiling of Reconstruction x + c V (x) =a sinc b + d V (x) x 8

20 Spatial Profiling of Reconstruction x + c V (x) =a sinc b + d V (x) Background noise x 8

21 Spatial Profiling of Reconstruction x + c V (x) =a sinc b + d V (x) Background noise x 8

22 Targeting a Moving Receiver Refresh the sona before it gets stale Peak-To-Peak Voltage (V) V(t) Time (s) 9

23 Targeting a Moving Receiver Refresh the sona before it gets stale Peak-To-Peak Voltage (V) V(t) Time (s) 9

24 Targeting a Moving Receiver Refresh the sona before it gets stale Peak-To-Peak Voltage (V) V(t) Time (s) 9

25 Targeting a Moving Receiver Refresh the sona before it gets stale Peak-To-Peak Voltage (V) V(t) Time (s) 9

26 Targeting a Moving Receiver Refresh the sona before it gets stale Peak-To-Peak Voltage (V) Dead time Time (s) 9 V(t)

27 Targeting a Moving Receiver Refresh the sona before it gets stale Peak-To-Peak Voltage (V) Dead time Time (s) 9 V(t)

28 Targeting a Moving Receiver Refresh the sona before it gets stale Peak-To-Peak Voltage (V) Experimental Results Time (s) 1 V(t)

29 Potential WPT System Initialization Steady State Supplier searches for participating devices (which may or may not have charge) Small fraction of power reflected by device, allowing supplier to find new location Talk Session 5 Friday,17:45 (Selective Collapse of Nonlinear Time Reversed Electromagnetic Waves)

30 Limitations And Future Work Transfer efficiency Use multiple channels Environmental losses Investigate and mitigate Dead time Use dedicated hardware TX and calculate new sona simultaneously These limitations are dependent on our lab equipment, they are not fundamental limitations of the technique 12

31 Summary Time Reversal is a promising new basis for long-range WPT can transmit energy to receivers in motion does not require the receiver to be powered Poster Session 2 Friday,14:4 (Time Reversed Wave Propagation as a Novel Method of WPT) Talk Session 5 Friday,17:45 (Selective Collapse of Nonlinear Time Reversed Electromagnetic Waves) frank@cs.umd.edu anlage@umd.edu 13