The design of auto-tuning capacitive power transfer for rotary applications using phased-locked-loop

Abstract

<span>Wireless power transfer (WPT), through the transmission of contactless energy, is not only being used for charging batteries in smartphones, but it is also being increasingly used in the field of industrial applications. The capacitive based approach is utilized in this paper because of its ability to transmit power in a metal surrounding environment where the inductive-based approach failed to perform. This work focuses on the coupling study of a rotary CPT application where the power supply is stationary while the load rotates and therefore allows the load to rotate 360<sup>o</sup> free rotation. The Class E MOSFET power inverter is used here due to its ability to achieve high efficiency compared to other class of converters at high frequency. The prototype of the CPT for rotary application has also been successfully developed with disk plate thickness of 1mm-2mm. Overall, the developed CPT system for rotary application is able to deliver 5.5Watt with 83.33% efficiency. To enhance the power efficiency and ZVS conditions, a self-tuning circuit using phased-locked-loop has been proposed in this paper. The efficiency of the developed system with self-tuning circuit is increased to 97.%.</span>

A Comprehensive Review on Wireless Capacitive Power Transfer Technology: Fundamentals and Applications

“…Aerodynamic fluid bearings are proposed to increase the coupling capacitance by decreasing the distance between the stationary and moving parts [272]. To improve the system efficiency and robustness, an auto-tuning circuit using PI control method [273], the output feedback control method [180], and a cascaded boost-class E converter structure [274] are suggested for rotary applications. A three-phase CPT system is suggested for rotary applications to provide balanced and good coupling between the electrodes during rotations [270].…”

“…• Increased power transfer capacity [114,207] • Reduced voltage stress [114] • Increased transfer distance [114] • High tolerance to parameter variations [180,270,274] • Increased coupling capacitance [272,310] • High efficiency [273] • More influence of parasitic components [114,270,272,310] • Control complexity [180,273] • Increased power loss [207] • Requires extra circuitry [274] Biomedical -…”

Machine Learning Approach of Optimal Frequency Tuning for Capacitive Wireless Power Transfer System

“…This effort achieved an efficiency of 70% at any distance. Nabila et al [22] developed a circuit for the CPT system to self-tune based on phased-locked-loop. The proposed system's efficiency with a self-tuning circuit is enhanced to 97%.…”

Design guideline of capacitive power transfer system to achieve targeted output power

“…The CPT technique has been found in various applications, especially in biomedical implants [14]- [19]. Its further applications are electric vehicles [20]- [22], unmanned aerial vehicles (UAVs) [23]- [25], autonomous underwater vehicles (AUVs) [26], portable devices [27], and rotary applications [28].…”