Output-Voltage Adaptive of Omnidirectional Wireless Power Transfer Based on Receivers With Digital Coils

Omnidirectional wireless power transfer (WPT) can provide power for multiple loads at any position in space. The voltage required for different loads is unavoidably various, and the characteristics of load may also change at different stages of power replenishment (e.g., battery impedance). WPT needs to adjust the supply voltage and power in real time to meet the needs of different loads and diverse working conditions. This article presents a receiver composed of digital receiving coil (DRC) with voltage adaptive regulation. The layers of DRC are changed to adjust the coupling state of magnetic coupling mechanism (MCM). The voltage of DRC is actively adjusted to maintain continuous stability of power supply, or to meet the specific requirements for different stages. The proposed design can achieve the peak-to-peak voltage of DRC stabilized in the range of 8.5–14 V with the transmitting distance varying from 28 to 47 cm, 18–26 V with the load of 3–100
$\Omega $
, and 8–13.5 V with the input dc voltage changing from 11.5 to 46 V. When the layers of DRC are adjusted, different voltages can be obtained with fixed distance, load, and input DC voltage. The designed receiver with DRC is less sensitive to load, transmission distance, rotation angle, and other factors, and meet the differential voltage requirements of space multiload. The proposed system can reduce the design difficulty and requirements of the converter, and will promote the application of WPT in the field of power supply for Internet of Things (IoT) equipment.