Adaptive Self-Tuned Mixed-Signal Controller IC for Resonant Wireless Power Transfer

This paper introduces an adaptive self-tuned controller IC for resonant wireless power transfer (RWPT) systems. The new controller IC comprises an on-the-fly very-high-frequency tracking hardware with high-resolution and an independent high-resolution digital PWM-based (HR-DPWM) current programmed control. These facilitate precise frequency generation as well as adaptive tuning of the reactive components in the matching network, which translate into tight current/power regulation capabilities while retaining optimized power transfer conditions. This enables to effectively disengage the power delivery capabilities from the variations of the resonators, electrical circuits and wireless medium. A fully synthesizable digital two-loop controller has been realized through HDL tools, and several new IP blocks have been developed and described in-detail: a delay-line (DL) based phase detector, high-resolution digital controlled oscillator (DCO), HR-DPWM. To fully exploit the benefits of digital electronics, reduce power consumption and save area, the digital core of the controller has been designed through asynchronous architecture, eliminating the need of high-speed clock and its related architecture. The mixed-signal controller IC has been designed and implemented in 0.18 µm, resulting in total effective silicon area of 1.44 mm
²
. Post-layout results of the fabricated IC operating in closed-loop are provided, demonstrating the performance and benefits of the new controller for meeting the requirements of resonant-based WPT systems. In addition, to validate and verify the controller core prior to IC fabrication, the control algorithm has been implemented on FPGA. To demonstrate closed-loop operation of a wireless power system, an experimental LC resonant capacitive-based WTP system has been constructed. The effectiveness of the controller is well demonstrated and evaluated at the MHz range up to an airgap of 200 mm, validating adaptive self-tuned system.