Near Field Wireless Powering of Deep Medical Implants
Abstract
:1. Introduction
2. Wireless Power Transfer (WPT) System Design
2.1. Electromagnetic Field Model
2.2. Transmitting Side Design
- (1)
- design of the primary coil that maximizes the working area inside the human body where the AIMD is located;
- (2)
- definition of the most suitable operational frequency that allows a deep penetration of the time-varying magnetic field without exceeding the EMF safety limits.
- -
- the excitation is given by two series-connected elliptical solenoids with top-bottom configuration assuming the human body in upright position;
- -
- the human body is assumed to be a simple multilayer cylinder with vertical axis.
2.3. Receiving Side Design
- -
- Test case #1: silicone;
- -
- Test case #2: titanium;
- -
- Test case #3: titanium covered with an external layer of ferrite with thickness tfe = 0.4 mm.
2.4. WPT Electrical Performances
- -
- N2 = 12 for the test case #1 (silicone);
- -
- N2 = 20 for the test case #2 (titanium housing);
- -
- N2 = 8 for the test case #3 (titanium housing + ferrite).
2.5. Thermal Analysis
3. WPT System Demonstrator
3.1. Electrogeometrical Configuration
- -
- Test case #1: N2 = 12, rc = 4.5 mm, ws = 1.9 mm, hc = 28 mm.
- -
- Test case #2: N2 = 20, rc = 4.5 mm, ws = 0.9 mm, hc = 28 mm.
- -
- Test case #3: N2 = 8, rc = 4.5 mm, ws = 3 mm, hc = 28 mm, MnZn ferrite [11] with thickness tfe = 0.4 mm.
3.2. Numerical and Experimental Results
4. Conclusions
Author Contributions
Funding
Conflicts of Interest
References
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Avg 2 × 2 × 2 mm3 E (V/m) | Avg 5 mm E (V/m) | 10 g avg SAR (W/kg) | |
---|---|---|---|
Calculated | 324 | 484 | 1.98 |
BR Limit | 540 (ICNIRP) | 835 (IEEE) | 2.00 (ICNIRP-IEEE) |
Angle θ | Silicone | Titanium | Titanium + Ferrite Cover |
---|---|---|---|
0° | 3.62 × 10−10 | 1.15 × 10−10 | 2.69 × 10−9 |
30° | 3.16 × 10−10 | 1.01 × 10−10 | 2.34 × 10−9 |
60° | 1.90 × 10−10 | 6.54 × 10−10 | 1.36 × 10−9 |
80° | 0.76 × 10−10 | 0.33 × 10−10 | 0.48 × 10−9 |
Test Case | L2 (μH) | M (nH) | R2 (mΩ) | |
---|---|---|---|---|
#1 | Numerical | 430 | 18 | 120 |
Measured | 480 | 17 | 180 | |
#2 | Numerical | 540 | 13 | 630 |
Measured | 490 | 10 | 540 | |
#3 | Numerical | 1420 | 84 | 840 |
Measured | 1220 | 77 | 920 |
Test Case | Primary Coil Current (A) | Efficiency η | ||
---|---|---|---|---|
Numerical | Measured | Numerical | Measured | |
#1 | 0.20 | 0.23 | 0.40 | 0.34 |
#2 | 0.49 | 0.61 | 0.09 | 0.07 |
#3 | 0.14 | 0.15 | 0.60 | 0.58 |
dpx (mm) | dpz (mm) | Efficiency η | Primary Coil Current (A) |
---|---|---|---|
0 | 0 | 0.47 | 0.25 |
50 | 0 | 0.51 | 0.20 |
100 | 0 | 0.52 | 0.18 |
0 | 50 | 0.55 | 0.20 |
50 | 50 | 0.58 | 0.16 |
100 | 50 | 0.58 | 0.15 |
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Campi, T.; Cruciani, S.; De Santis, V.; Maradei, F.; Feliziani, M. Near Field Wireless Powering of Deep Medical Implants. Energies 2019, 12, 2720. https://doi.org/10.3390/en12142720
Campi T, Cruciani S, De Santis V, Maradei F, Feliziani M. Near Field Wireless Powering of Deep Medical Implants. Energies. 2019; 12(14):2720. https://doi.org/10.3390/en12142720
Chicago/Turabian StyleCampi, Tommaso, Silvano Cruciani, Valerio De Santis, Francesca Maradei, and Mauro Feliziani. 2019. "Near Field Wireless Powering of Deep Medical Implants" Energies 12, no. 14: 2720. https://doi.org/10.3390/en12142720