Skip to main content
Log in

Efficiency analysis and optimization of wireless power transfer system for freely moving biomedical implants

  • Article
  • Published:
Science China Technological Sciences Aims and scope Submit manuscript

Abstract

In the wireless power transfer system for freely moving biomedical implants, the receiving unit was generally inefficient for the reason that its design parameters including the receiving coil’s dimension and receiving circuits’ topology were always determined by experiments. In order to build the relationship between these parameters and the total transfer efficiency, this paper developed a novel efficiency model based on the impedance model of the coil and the circuit model of the receiving circuits. According to the design constraints, the optimal design parameters in the worst case were derived. The results indicate that the combination of the two-layered receiving coil and half-bridge rectifier has more advantages in size, efficiency and safety, which is preferred in the receiving unit. Additionally, when the load resistance increases, the optimal turn number of the receiving coil basically keeps constant and the corresponding transmitting current and total efficiency decrease. For 100 Ω load, the transmitting current and total efficiency in the worst case were measured to be 5.30 A and 1.45% respectively, which are much better than the published results. In general, our work provides an efficient method to determine the design parameters of the wireless power transfer system for freely moving biomedical implants.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

References

  1. Iddan G, Meron G, Glukhovsky A. Wireless capsule endoscopy. Nature, 2000, 405: 417

    Article  Google Scholar 

  2. Johannessen E A, Lei Wang E A, Wyse C, et al. Biocompatibility of a lab-on-a-pill sensor in artificial gastrointestinal environments. IEEE Trans Biomed Eng, 2006, 53: 2333–2340

    Article  Google Scholar 

  3. Quirini M, Webster R J, Menciassi A, et al. Design of a pill-sized 12-legged endoscopic capsule robot. In: IEEE International Conference on Robotics and Automation. Italy: IEEE, 2007. 1856–1862

    Google Scholar 

  4. Hui S Y R, Zhong W, Lee C K. A critical review of recent progress in mid-range wireless power transfer. IEEE Trans Power Electron, 2014, 29: 4500–4511

    Article  Google Scholar 

  5. Ciuti G, Menciassi A, Dario P. Capsule endoscopy: From current achievements to open challenges. IEEE Rev Biomed Eng, 2011, 4: 59–72

    Article  Google Scholar 

  6. Fang X L, Liu H, Li G Y, et al. Circuit model based design and analysis for a four-structure-switchable wireless power transfer system. Sci China Technol Sci, 2015, 58: 534–544

    Article  Google Scholar 

  7. Ma G, Yan G, He X. Power transmission for gastrointestinal microsystems using inductive coupling. Physiol Meas, 2007, 28: 9–18

    Article  Google Scholar 

  8. Lenaerts B, Puers R. An inductive power link for a wireless endoscope. Biosens Bioelectron, 2007, 22: 1390–1395

    Article  Google Scholar 

  9. Sun T J, Xie X, Li G L, et al. A two-hop wireless power transfer system with an efficiency-enhanced power receiver for motion-free capsule endoscopy inspection. IEEE Trans Biomed Eng, 2012, 59: 3247–3254

    Article  Google Scholar 

  10. Carta R, Thoné J, Puers R. A wireless power supply system for robotic capsular endoscopes. Sensor Actuat A-Phys, 2010, 162: 177–183

    Article  Google Scholar 

  11. Jia Z W, Yan G Z, Jiang P P, et al. Efficiency optimization of wireless power transmission systems for active capsule endoscopes. Physiol Meas, 2011, 32: 1561–1573

    Article  Google Scholar 

  12. Jia Z, Yan G, Liu H, et al. The optimization of wireless power transmission: Design and realization. Int J Med Robot Comput Assist Surg, 2012, 8: 337–347

    Article  Google Scholar 

  13. Yang Z, Liu W, Basham E. Inductor modeling in wireless links for implantable electronics. IEEE Trans Magn, 2007, 43: 3851–3860

    Article  Google Scholar 

  14. Jow U M, Ghovanloo M. Design and optimization of printed spiral coils for efficient transcutaneous inductive power transmission. IEEE Trans Biomed Circuit Syst, 2007, 1: 193–202

    Article  Google Scholar 

  15. Ramrakhyani A K, Mirabbasi S, Mu Chiao S. Design and optimization of resonance-based efficient wireless power delivery systems for biomedical implants. IEEE Trans Biomed Circuit Syst, 2011, 5: 48–63

    Article  Google Scholar 

  16. Pinuela M, Yates D C, Lucyszyn S, et al. Maximizing DC-to-load efficiency for inductive power transfer. IEEE Trans Power Electron, 2013, 28: 2437–2447

    Article  Google Scholar 

  17. Jourand P, Puers R. A Class-E driven inductive power delivery system covering the complete upper body. Sensor Actuat A-Phys, 2012, 183: 132–139

    Article  Google Scholar 

  18. Jegadeesan R, Nag S, Agarwal K, et al. Enabling wireless powering and telemetry for peripheral nerve implants. IEEE J Biomed Health Inform, 2015, 19: 958–970

    Article  Google Scholar 

  19. Liu H, Shao Q, Fang X. Modeling and optimization of Class-E amplifier at subnominal condition in a wireless power transfer system for biomedical implants. IEEE Trans Biomed Circuit Syst, 2016, 1–9

    Google Scholar 

  20. Sokal N O, Sokal A D. Class E-A new class of high-efficiency tuned single-ended switching power amplifiers. IEEE J Solid-St Circ, 1975, 10: 168–176

    Article  Google Scholar 

  21. Wheeler H A. Simple inductance formulas for radio coils. Proc Inst Radio Eng, 1928, 16: 1398–1400

    Google Scholar 

  22. Raju S, Wu R, Chan M, et al. Modeling of mutual coupling between planar inductors in wireless power applications. IEEE Trans Power Electron, 2014, 29: 481–490

    Article  Google Scholar 

  23. Lope I, Carretero C, Acero J, et al. AC power losses model for planar windings with rectangular cross-sectional conductors. IEEE Trans Power Electron, 2014, 29: 23–28

    Article  Google Scholar 

  24. Rosskopf A, Bar E, Joffe C. Influence of inner skin- and proximity effects on conduction in litz wires. IEEE Trans Power Electron, 2014, 29: 5454–5461

    Article  Google Scholar 

  25. Butterworth S. Eddy-current losses in cylindrical conductors, with special applications to the alternating current resistances of short coils. Philos Trans R Soc A-Math Phys Eng Sci, 1922, 222: 57–100

    Article  Google Scholar 

  26. Massarini A, Kazimierczuk M K. Self-capacitance of inductors. IEEE Trans Power Electron, 1997, 12: 671–676

    Article  Google Scholar 

  27. Lenaerts B, Puers R. Omnidirectional Inductive Powering for Biomedical Implants. Belgium: Springer, 2009

    Book  Google Scholar 

  28. Lenaerts B, Puers R. Inductive powering of a freely moving system. Sensor Actuat A-Phys, 2005, 123–124: 522–530

    Article  Google Scholar 

  29. Shiba K, Nagato T, Tsuji T, et al. Energy transmission transformer for a wireless capsule endoscope: Analysis of specific absorption rate and current density in biological tissue. IEEE Trans Biomed Eng, 2008, 55: 1864–1871

    Article  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Hao Liu.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Shao, Q., Liu, H. & Fang, X. Efficiency analysis and optimization of wireless power transfer system for freely moving biomedical implants. Sci. China Technol. Sci. 60, 91–101 (2017). https://doi.org/10.1007/s11431-015-0554-y

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s11431-015-0554-y

Keywords

Navigation