A method to achieve simultaneous wireless power transfer and full-duplex communication with a pair of coupling coils is proposed in this article. A double-side LCC compensation topology for power transfer is adopted, while the data transfer channel is constituted by a four resonance dual-rejection structure. In the process of power transfer and full-duplex communication, from the view of data transmitting and receiving, the data transmitting/receiving circuits on one side can not only transmit/receive the desired data carriers but also block the interference data carriers, and from the view of power transfer, the rated power transfer can be realized with little influence. Moreover, the parameter design method of the proposed system is given. Besides, the interference between the power wave and data carriers and the crosstalk between the data carriers are analyzed. Finally, an experimental prototype is built, which achieves an output power of 600 W and a data transmission rate of 80 kbps.

In this letter, a new coupling structure for dynamic wireless power transfer (DWPT) systems is proposed. Bipolar coils are symmetrically placed on the transmitter unipolar coils, resulting in natural decoupling between the bipolar coils and the unipolar coils. This special structure can mitigate the self-couplings between the adjacent unipolar transmitter coils and hence, facilitate the design of the compensation circuit. Another remarkable advantage of this design is that it can lead to a stable mutual coupling between the transmitter array and the receiver when the receiver moves along the transmitter, making it a natural fit for DWPT applications. Furthermore, to reduce the electromagnetic interference (EMI) and power loss, an automatic segmented control scheme is implemented, and a position detection method by monitoring the primary current is developed. The feasibility of the proposed coupling structure and the position detection method are verified on a laboratory prototype with 72V output voltage. The experimental results show that, the power fluctuation is within ±2.5%, and system efficiency is around 90%. (This letter is accompanied by a video demonstrating the experimental test).

In this paper, a robust wireless power transfer system is proposed with self alignment capability and controllable output current characteristics for static charging of automatic guided vehicles (AGVs). A reconfigurable circuitry is designed to work initially in an inductor-capacitor-capacitor-series (LCC-S) compensation mode for achieving magnetic field self alignment, then switched to an LCC-LCC configuration for wireless charging. Apart from the passive components used for wireless power transfer, no additional components such as cameras, sensors, or dedicated sensing coils are needed for self alignment. The induced voltage of a series tuned Q-coil on the load side is used for the AGV to automatically adjust its position. The vehicle will be self aligned when the induced voltage becomes null, then the system is switched to a controllable constant current (CC) charging mode. A prototype is built which demonstrates that the output charging current is controllable and can be kept constant against load variations. The experimental results show the proposed system can realize an 89.1% dc-dc power transfer efficiency (PTE) at an output current of 30A and output voltage of 48V.

This article proposes a free-positioning omnidirectional wireless power transfer (WPT) system with a reticulated planar transmitter, which enables multiple receivers to be powered simultaneously in arbitrary positions and orientations. The reticulated planar transmitter is equipped with four interleaved and overlapped meander coils, thus, a three-dimensional (3-D) rotating magnetic field is generated with the designed excitation current. Therefore, only a planar single-coil (such as a loop-type coil) is required to realize free-positioning omnidirectional WPT. According to the theoretical modeling of the magnetic field, the excitation current that can generate a 3-D rotating magnetic field is given. To obtain a uniform and strong magnetic field distribution, the transmitter grid width is optimized. Furthermore, an excitation current modulation strategy based on phase-shift control is presented to regulate the amplitude of the excitation current. The experimental results show that the output power is greater than 13.1 W no matter how the center of the receiver moves or rotates freely within 400 × 400 mm. When five receivers are powered simultaneously in different positions and orientations, 82.5 W total output power and 55.6% efficiency can be achieved. The experimental results demonstrate that free-positioning omnidirectional WPT can be realized with only planar single-coil receivers by using the proposed reticulated planar transmitter and its excitation current modulation strategy.

For a general multi-coil magnetic coupling wireless power transfer (MC-WPT) system with different coil properties and non-negligible cross couplings, there is no analytical solution which connects the resonant frequencies of the system to its electric parameters. Establishing such a generalized analytical solution not only permits quantitative analysis of resonant points but also provides a generic platform for the physical interpretation of resonance. For this purpose, a novel modeling and analysis method of integrating time-domain and frequency-domain is proposed in this paper, with that all possible resonant points of arbitrary coil MC-WPT systems can be quickly and accurately determined. Firstly, an accurate state space model of a general MC-WPT system with arbitrary number of transmitters, repeaters and receivers is established and the analytical current response on each circuit is derived. Then several key system concepts about resonance are elucidated, based on which the generalized analytical expressions of resonant points of MC-WPT systems, including resonant frequencies and corresponding powers and efficiencies, are derived. Further, the physical interpretation along with the mathematic relationships of several key easy-confusing concepts are deduced, which provides systematic theoretical criteria for the selection of operating frequency to achieve the resonant states for MC-WPT systems.

This article proposes a tripolar plane-type (TPT) transmitter enabling three-dimensional (3-D) omnidirectional wireless power transfer (WPT) for consumer electronics, such as mobile phones and tablet computers. The proposed TPT transmitter is a 2-D plan-type structure, but it shows a 3-D omnidirectional power transmitting capability. This structure consists of two crossed bipolar coils and a unipolar circular coil, and the three coils are mutually decoupled naturally. By calculating the magnetic field distribution generated by the TPT transmitter, a 3-D omnidirectional magnetic field can be obtained. Then, a detailed circuit topology based on the inductor-capacitor-capacitor-series compensation networks and full-bridge inverters with phase-shift control is modeled and analyzed. On this base, an excitation current vector modulation strategy based on a targeting magnetic field is designed, which can improve and stabilize the system output power and efficiency. Finally, an experimental prototype is set up to verify the 3-D omnidirectional power transmitting capability of the proposed TPT transmitter and the effectiveness of the designed current vector modulation strategy. Besides, the superiority of the proposed 3-D omnidirectional WPT system is verified by comparison with other methodologies. The experimental results show that the system output power and efficiency are maintained at 61.4–80.6W and 80.7%–85.2% under arbitrary angular misalignment of the receiver.