Power transmission for gastrointestinal microsystems using inductive coupling

Abstract

Much research on the development of a robotic capsule and microrobot for the diagnosis of gastrointestinal diseases has been carried out. The powering of these microsystems is becoming very important as the implementation of such systems is becoming more feasible by advances in relevant technologies. A wireless power transmission system employing two coils, based on inductive coupling, is discussed in this note. The coupling coefficient between the two coils was measured on axial, lateral and pitch misalignment. The power transmission efficiency was deduced and optimized by selecting proper tuning capacitors and transmission frequency. A serial resonant circuit (SRC) on a receiving side is more adaptive by comparison with parallel resonant circuit (PRC) topology. A multi-receiving coil structure was proposed and examined in an attempt to resolve the orientation indetermination problem of a receiving coil. Experiments show that a dc power level up to 170 mW, with an efficiency of 1.3%, could be steadily received when the receiving coil was placed at the center of the transmitting coil, which can meet the requirement for electric power of some microsystems.

Application of Wireless Power Transmission Systems in Wireless Capsule Endoscopy: An Overview

“…Although, the intensity of the generated magnetic field depends on the magnitude of the TC driving signal, the uniformity of the field depends completely on the type and the design structure of the TC [64]. In general, they are two types of TC which include solenoid coils [12,36,61–63,65–69] and Helmholtz coils [30,33,70]. The solenoid coil can be arranged in four different forms: (i) single solenoid [65]; (ii) a pair of solenoids [67]; (iii) a pair of double layer solenoids [12] and (iv) segmented solenoids [63].…”

“…The diameter of TC is one of the vital parameters which has been chosen in a wide range from 30 to 75 cm. Although, the smallest TC diameter of 30 cm may not be compatible for healthy and obese patients, nonetheless it has been used in many studies to validate their prototype of WPT systems [63,65]. In general, a smaller diameter of TC improves efficiency because it allows a better coupling between TC and RC.…”

“…A study by [65] revealed that, for a series resonance circuit (SRC), matching the ESR with the load resistance results in maximum power transfer from RC to load.…”

Personalized biomedical devices & systems for healthcare applications

“…However, unpredictable orientation and distance of the receiver makes it a very challenging task [77]. Misalignment of transmitting and receiving coils can significantly decrease the transmission efficiency or even result in zero output power.…”

“…Misalignment of transmitting and receiving coils can significantly decrease the transmission efficiency or even result in zero output power. To enhance the efficiency and avoid zero-crossing in output power, multiple primary or secondary coils can be used [77]. These configurations have been investigated by Lenaerts and Puers [78].…”