Star-Shaped Coils in the Transmitter Array for Receiver Rotation Tolerance in Free-Moving Wireless Power Transfer Applications

Abstract

Wireless power is one of the new promising technologies for IoT applications. The use of arrays for power transfer to free-moving objects has revolutionized wireless power transmission (WPT) applications. Herein, we present an extendable platform for transmitting power to a moving object receiving power from an array. The transmitter (TX) consists of two overlapping layers of square planar coils rotated 45 degrees to each other to provide the best electromagnetic flux coverage. Each layer consists of four coils to further control the power supply to the small receiver (RX) coil. This overlapping star-shaped array is stimulated automatically by a power amplifier. This smart stimulation can deliver uniform power to the receiver regardless of rotation and misalignment inconsistencies by using the geometry of the transmitter array. Moreover, by changing the direction of the current of each small square component in each array using the flower-shaped current, a receiver coil perpendicular to the transmitter’s plate can obtain power comparable with conventional structures. We use ADS-HFSS simulation to verify the fabrication and measurement results. The proposed transmitter achieves an average of 18.2% power transfer efficiency (PTE) to RX and at 90° angular misalignment, 11.5% PTE, while the conventional structure transfers no power to the perpendicular RX coil. A future application of the transmitter can be the investigation of the neurobehavioral of free-moving animals and brain–machine interface studies in medicine.

Multi-resonator Wireless Inductive Power Link for Wearables on the 2D Surface and Implants in 3D Space of the Human Body

“…The parallel-connected multi-resonator Tx array designs have shown excellent performance in wirelessly powering (1) wearable headstages in animal cages (for long-term in-vivo experiments with freely moving small animals), (2) IMDs, and (3) multiple smartphones simultaneously, using a single power source [40]- [43], [45]. Such configuration provides great uniformity of power transfer efficiency (PTE) and power delivered to the load (PDL), as well as enabling natural power localization property, only activating the resonator near the Rx unit with no additional circuitry [39]- [41]. However, the parallel approach with horizontally oriented Tx resonators does not efficiently deliver power to the vertically oriented implants or wearables.…”

Design of a Highly Compatible Underwater Wireless Power Transfer Station for Seafloor Observation Equipment

“…Stacking with 2-3 large coils makes the power transmission area broader and the field distribution more desirable. For instance, two overlapping layers of square planar coils are utilized to generate a magnetic field distribution with high rotation tolerance [30]. Moreover, multi-resonator arrays are utilized and optimized to obtain positioning freedom with better performance [31].…”

Dual-Module Ultrawide Dynamic-Range High-Power Rectifier for WPT Systems

“…Wireless power transfer (WPT) represents a non-contact method of delivering energy through the air, eliminating the need for traditional current-carrying cords. The prominence of WPT has surged due to its flexibility; safety features; and diverse applications across various fields, including electric vehicles [1][2][3], implantable medical devices [4][5][6][7], and the charging of portable electronic devices [8][9][10].…”