Omnidirectional Inductive Powering for Biomedical Implants

ISBN-13: 9781402090745 / Angielski / Twarda / 2008 / 222 str.

Bert Lenaerts; Robert Puers

Opis

Omnidirectional Inductive Powering for Biomedical Implants investigates the feasibility of inductive powering for capsule endoscopy and freely moving systems in general. The main challenge is the random position and orientation of the power receiving system with respect to the emitting magnetic field. Where classic inductive powering assumes a predictable or fixed alignment of the respective coils, the remote system is now free to adopt just any orientation while still maintaining full power capabilities. Before elaborating on different approaches towards omnidirectional powering, the design and optimisation of a general inductive power link is discussed in all its aspects. Special attention is paid to the interaction of the inductive power link with the patient s body. Putting theory into practice, the implementation of an inductive power link for a capsule endoscope is included in a separate chapter."

Spis treści

Abstract. List of Abbreviations and Symbols. 1 Introduction. 1.1 Wireless Power Transmission. 1.2 Types of Wireless Power Transmission. 1.3 A Biomedical Perspective. 1.4 Inductive Links. 1.5 Conclusions. 1.6 What to Expect. 2 Magnetic Induction. 2.1 Maxwell’s Equations. 2.2 Conductive Wire. 2.3 Inductance. 2.4 Inductor Models. 2.5 Finite Element Modelling. 2.6 Conclusions. 3 Inductive Link Design. 3.1 Link Equations. 3.2 Loose-coupling Approximation. 3.3 Tertiary Circuits. 3.4 Link Optimisation. 3.5 Misconceptions about k and Q. 3.6 Conclusions. 4 Power Converters and Voltage Regulators. 4.1 Rectifiers. 4.2 Inverters. 4.3 Voltage Regulators. 4.4 Conclusions. 5 Omnidirectional Coupling. 5.1 Problem Definition. 5.2 Multiple Primary Coils. 5.3 Multiple Secondary Coils. 5.4 Conclusions. 6 Biological Tissue Interaction. 6.1 Electromagnetic Fields in Biological Tissue. 6.2 Health Effects of Electromagnetic Fields. 6.3 Exposure Limits and Regulations. 6.4 Examples from Biomedical Engineering Practice. 6.5 Conclusions. 7 An Inductive Power Link for a Capsule Endoscope. 7.1 Wireless Endoscopy. 7.2 Design: Choices and Motivation. 7.3 Fabrication. 7.4 Measurement. 7.5 Biological Tissue Interaction. 7.6 Conclusions. 8 A Class E Driver for Deformable Coils. 8.1 Class E ZVS Inverter with Transductor. 8.2 Control Loop. 8.3 Measurement Results. 8.4 Conclusions. 9 Conclusions. 9.1 Comprehensive Summary. 9.2 Main Contributions and Achievements. 9.3 Further Research. Appendix: Coil Measurements. A.1 Single Coil Characterisation. A.2 Coupling Characterisation. References. Index.

Blurb

In the year 2000, a capsule endoscope was introduced on the market for diagnosis of small bowel diseases. This pill, about one centimeter in diameter, takes images of the gastric track and transmits them wirelessly to the outside world. Since the capsule is battery powered, the limited energy budget restricts both the amount and the quality of images that can be shot. To resolve this limitation, Omnidirectional Inductive Powering for Biomedical Implants investigates the feasibility of inductive powering for capsule endoscopy and freely moving systems in general. The main challenge is the random position and orientation of the power receiving system with respect to the emitting magnetic field. Where classic inductive powering assumes a predictable or fixed alignment of the respective coils, the remote system is now free to adopt just any orientation while still maintaining full power capabilities. Before elaborating on different approaches towards omnidirectional powering, the design and optimisation of a general inductive power link is discussed in all its aspects. Useful rectifier and inverter topologies are presented, including a class E driver that copes with coil deformations. Special attention is paid to the interaction of the inductive power link with the patient’s body. Putting theory into practice, the implementation of an inductive power link for a capsule endoscope is included in a separate chapter.