Signal and Power Synchronous Transmission in WPT System Based on Capacitance Modulation

The original intention of wireless power transmission was to make the power supply more flexible, but compared with wired transmission, its efficiency has always restricted its application. Therefore, the performance characteristics of wireless power transmission have always been a research focus in wireless power transmission. As for induction power transmission, its coupling mechanism is the key part of the transmission system, and its optimal design directly affects the power, efficiency and transmission distance of the system. The research results of the coupling mechanism of an inductive power transmission system in recent years are reviewed, and the effects of coil structure, coupling mechanism material and coil parameter design on efficiency characteristics are analyzed. This paper analyzes the existing optimization methods and existing problems, and points out the direction for the optimal design of the coupling mechanism of a wireless power transmission system.

Synchronous transmission of signal is as important as wireless power transmission. In order to solve the problem of mutual interference between power and signal in the wireless synchronous transmission system of power and signal with shared channel, this paper proposes a new electric field-coupled power and signal transfer system using common mode and differential mode separation circuits. Based on the principle of transmitting power in common mode and transmitting signal in differential mode, this paper establishes the circuit models of power transmission channel and signal transmission channel, and analyzes the working performance of the system in detail according to the circuit theory. At the same time, the design principles of the system parameters are given in this paper. Finally, simulation and experiment verify the feasibility of the proposed system, and the effect of plate capacitance change on system performance is studied.

With the development of industrialization, more and more research topics have been focused on increasing the transmission power of wireless power transmission systems. This paper studies the parallel technology of the modular inductive wireless power transmission system, calculates the resonance compensation network of it. Next, the current sharing strategy is proposed to improve accuracy.Then we derive a simulation model. After that, we simulate under different load conditions and get the corresponding output voltage and current.The results show that the system can transmit power and obtain a relatively stable voltage, and this system can effectively balance the current between the modules.

Antennas play a very important role in wireless power transmission (WPT) systems using microwave since they affect the system transmission efficiency. General requirements for an antenna used for WPT systems are high directivity and narrow beamwidth. This paper presents the design, simulation and fabrication of microstrip patch antenna arrays for close-range WPT systems. Various antenna prototypes such as single patch, 2×2, 2×4, 4×8 and 8×8 microstrip patch antenna arrays working at 2.45 GHz are proposed. The 2×4 microstrip patch antenna array is fabricated and measured using Anritsu 37364D Vector Network Analyzer and NSI2000 Nearfield System. Measurement results show that the fabricated antenna obtains a directivity of 14.7 dBi and a 3 dB beamwidth of 23.2 degree. The experiment with the WPT system is carried out. This paper also presents structure of a WPT system and the role each building block in the system.

In this paper are analyzed the main methods of wireless transmission of electrical energy, as well as their applications. For the beginning, there is a brief history of the development of the wireless electric power transmission technology. There are presented the principles of functioning of the main methods of wireless transmission of electrical energy, as well as the technical problems that need to be solved in the future. There are also presented the main applications of this technology, as well as the main companies that produce commercial wireless electrical power transmission equipment. Finally, we present the future opportunities of these wireless power transmission technologies and recommendations for future research topics in this field.

A chip-to-chip inductive wireless power transmission system is proposed and the feasibility is experimentally demonstrated for the first time. The circuit realized 2.5mW power transmission at the output DC voltage of 0.5V using 700 times 700mum on-chip planar inductors for the transmitter and the receiver. Methods to optimize the circuit design about the maximum transmission power and the simulated optimization results are discussed

Inductive power transmission depends on many parameters such as the distance and the alignment between the coils, the working frequency, the current excitation, the geometry and the property of the coils, etc. Exchanging power distance between coils in wireless power transmission using inductive link is generally low, it is shorter than the diameter of the sending coils. Consequently, increasing coil to coil distance causes a harm decrease of the transmitted power and the efficiency of the system. A major technical challenge affecting the use of this kind of power transmission is to find a way of sending energy to the target devices in an efficient and reliable manner taking into account this influencing effect. In this paper, we explored potential solutions to overcome this challenge by adopting a Multiple Input Single Output (MISO) coil system able to decrease the magnetic flux leakage and orientate the magnetic field to the receiving coil by powering the neighbor coils of the active ones in opposite direction. This technique can be implemented in many industrial applications such as supplying wireless sensors installed into a conveyor. Same parameters according the model of the coupled coils on SISO and MISO configurations are developed and simulations by finite element method are done. The investigation shows that the MISO orientated system is capable to transfer 42 mW over a 50 mm distance and reaching 30% efficiency.

According to the poor stability of the output constant current and the control complexity of the existing Inductive Coupled Wireless Power Transmission System, a seriesparallel compensation network is applied to push-pull converter. And the soft switch is realized by configuring the parameters of compensation network, and the constant-current output of the wireless power is realized without additional complex control system. Firstly, analysis of the push-pull converter to achieve the conditions of soft-switching. Secondly, based on the leakage inductance model of the transformer, combined with the Thevenin equivalent theorem, the parameters of the string-and-compensation are designed. Lastly, the push-pull soft-switching inductive coupled power transfer converter is designed and built.The feasibility of theoretical analysis and parameter design method are verified by the experimental results.

This paper presents a development of a low power wireless power transmission system. A phase shift phase-lock loop (PLL) control for WPT was also proposed. The proposed control strategy was used to optimize the phase offset between the fundamental primary side voltage and primary side current at all operating points. Then, the phase compensation can be achieved. In order to verify the proposed control scheme, a hardware prototype of the proposed wireless power transmission (WPT) system has been constructed. The coupling coefficient was measured at different air gaps and lateral offsets. Several simulations and experimental results such as voltage and current measurement of primary voltage and current were reported and discussed.

Autonomous Underwater Vehicle non-contact charging system using a separate structure, When the technology is used in the underwater environment, the inductive coupled power transmission system will produce a gap and eccentricity under the influence of the water shock, causing the coupling state changed, which will affect the output power. This paper presents a control algorithm based on neural network system that compensate the system output power by adding a DC/DC switching according to the changes of the magnetic coupling state, in order to achieve a stable output voltage.

Compensation topologies for wireless power transmission system in medical implant applications: A review

Wireless power transmission (WPT) technology has been widely applied in various fields, such as electric vehicles and wireless sensor networks. Magnetic coupling resonance technology is one of the most important technologies in wireless power transmission. A large number of experimental studies have shown that wireless power transmission systems have good power transmission performances when they work at the natural frequencies. Nevertheless, many relevant parameters‘ differences in design, such as the choice of coupling coil structures and parameters, the coupling coefficient between transmitting coil and receiving coil and the quality factor of each coil, will lead to changes in terms of transmission performances. To reduce these adverse effects and make the wireless power transmission system maintain better transmission efficiency, a resonant magnetic coupling four-coil model with Series-Series-Series-Series (SSSS) structure is established based on the equivalent circuit theory. An optimization factor α is proposed to evaluate the transmission performances of the wireless power transmission system. Parameters characteristics of the optimization factor α between the excitation coil and the transmitter coil in the established symmetric structural system model are analyzed in detail. By means of the simulation analysis software MATLAB, the influences of the distance between the excitation coil and the transmitter coil and their respective radius on the optimization factor α are analyzed. And the variation tendency of α with regard to the parameters of the excitation coil and the transmission coil is clarified. Also, the influence of the optimization factor α on the transmission efficiency of the wireless power transmission system is analyzed and the variation trend is cleared up. By studying the optimization factor, the selection specification of system parameters is analyzed and provides a theoretical basis for system design. A resonant magnetic coupling four-coil wireless power transmission experimental system was built through optimization design. Theoretical models and experimental measures are in good agreement in terms of the influence of system transmission distance on transmission efficiency. After optimization, the transmission efficiency is increased by 3.1% compared with the system before optimization

Wireless technology opens a wide range of research opportunities in all areas of electrical science, particularly in the electrical power sector. Nonetheless, it grows richer with each addition and change made by scientists and researchers. This entire project is based on Wireless Power Transmission systems, whose ultimate purpose is to transmit power in a uniform gain in a registered region. To accomplish this purpose, first, a schematic diagram was designed which has two parts. The first part is for transferring the power and the second part is for receiving the power. The power transferring part is modified as Antenna and the receiver part is Rectenna and both the antenna and rectenna were designed in CST software. A receiver circuit was designed for delivering the power which was designed in ADS software. The receiver circuit was constructed in three individual sections. They are antenna circuit, rectifier circuit, and buck converter. The resonance frequency of the system is 2.4GHz and after completing the analysis we get the output of (5.655 to 4.95) V DC in rectangular shaped patch antenna and (5.573 to 4.86) V DC in circular shaped patch antenna in (2 to 60) meter. In addition, we tried to figure out which antenna provides better output by differentiate the shape of the antenna. The project’s primary goal is to transmit power to a focused area and also determine the estimated cost, health concerns, and repercussions in terms of social, political, and technological factors.

An overall view of past, present and proposed wireless space power transmission projects is presented. Activities in the United States, Canada, France, the former Soviet Union and Japan are highlighted. The recent Japan-US space-to-space wireless power transmission demonstration ISYMETS is described as are the 1995 demonstrations of wireless power transmission systems in Kyoto, Japan, at the WPT 95 conference.

This paper proposes a novel method for extending the wireless power transmission distance for the dielectric embedded folded dipole antenna used as received rectenna. Proposed technique adopts parasitic elements to extend transmission distance. The parasitic elements are installed between the power transmission element and the power reception element. The parasitic element is working like directors of Yagi-Uda antenna. When the Yagi-Uda antenna's principle is applied to the extension of the power transmission distance, problems yield that the element spacing and the shape are restricted. To address the issues, the folded dipole antenna embedded in a dielectric material is adopted for power receiving rectenna to study the wireless power transmission efficiency. It was calculated using electromagnetic field analysis and kQ product when parasitic elements were installed between power transmission and reception antennas. The results exhibited that the wireless power transmission efficiency could be increased by 20% compared to the case where the parasitic elements were not installed. Furthermore, we conducted an LED lighting experiment using a microwave oven as a wave source, and revealed that the distance of wireless power transmission could be extended by 50 mm.