Resonant Wireless Research Articles

Effects of electromagnetic field emitted by a 90 kHz WPT system on the cognitive functions and neuronal excitation of mice

ABSTRACT The advantages of Magnetic Coupling Resonant Wireless Power Transfer (MCR-WPT) technology include long transmission distance, high efficiency, and high power. Therefore, it shows great potential in the field of smart home. This study aims to explore the specific impacts on the cognitive functions and neuronal excitation of mice exposed to the electromagnetic fields (EMF) emitted by the MCR-WPT platform, thereby providing biological solid experimental evidence for developing Wireless Power Transfer (WPT) technology. The research employed a frequency of 90 kHz, which is suitable for wireless charging of household appliances. Mice were exposed to EMF emitted by the WPT biosafety experimental platform for various durations. And they were divided into four groups (control group, 2-week exposure group, 4-week exposure group, and 8-week exposure group). Upon completion of the exposure period, the study employed the Novel Object Recognition (NOR) test to evaluate the learning and memory capabilities of the animals. Following this, whole-cell patch-clamp experiments were conducted to record the action potentials (AP) and potassium currents. It was revealed by our observations that, in comparison to mice without electromagnetic exposure, long-term exposure to WPT-emitted EMF resulted in accelerated release of action potentials, inhibited the activation of Voltage-Gated Potassium Channels (VGKCs) current, accelerated the deactivation of K+ channel current, and thus significantly improved the excitability of neurons in the dentate gyrus (DG) of the hippocampus of mice, but did not significantly affect cognitive function.

Systematic analysis of wireless energy transmission methods

Wireless energy transfer technology is a new type of power transmission technology that utilizes electric and magnetic fields as mediums. In contemporary society, there are three main methods of wireless energy transfer: magnetic coupling resonance, microwave radiation, and electromagnetic induction. Each of these methods has its unique advantages and limitations, leading to different application scenarios in practical life. This article provides a detailed introduction to the basic structure and principles of magnetic coupling resonance, microwave radiation, and electromagnetic induction wireless energy transfer. Through comparative analysis of the characteristics of these three transmission methods, it explores their specific applications in various industries and life domains. Additionally, the article examines the challenges faced by today's wireless energy transfer technology, such as transmission efficiency, safety, cost, standardization, and technical difficulties. Finally, the article envisions the future development of wireless energy transfer technology, suggesting that as the technology continues to progress and improve, it will see broader application, bringing more convenience to people's lives and promoting integration with other fields to form more efficient and sustainable solutions.

Analysis and Comparison of the Compensation Topologies of Magnetic Coupled Resonant Wireless Charging for Electric Vehicles

In recent years, with the rise of electric vehicle industry and people’s increasing demand for convenient life, wireless charging technology used on electric vehicles has become one of the research hotspots. Magnetic coupled resonant wireless power transmission (MCR-WPT) has also been widely concerned because of its high suitability for electric vehicles. This paper mainly focuses on the compensation topologies of magnetic coupled resonant wireless charging for electric vehicles, analyzes 3 types of compensation topologies: P-S, P-P and LCL-LCC. Firstly, the transmission efficiency of these 3 topologies is analyzed from the theoretical point of view. Then, their transmission capacity under different coupling coefficients is compared through simulation. It is found that, in the reality where the coupling coefficients are low, P-S compensation topology should be preferred. Furthermore, by changing the load resistance, it is found that LCL-LCC compensation topology has high stability, which is suitable for scenarios that have long usage period.

Design of a Magnetically Coupled Resonant Implantable Medical Device Wireless Power Transmission System

This paper systematically describes the design and optimisation strategy of wireless charging technology for implantable medical devices. Starting from the theoretical basis of magnetically coupled resonant wireless power transmission (MCR-WPT), an efficient transmission circuit is designed and the resonant circuit characteristics are analysed. Meanwhile, the effects of the outer diameter, the number of turns of the transmitting coil and the turns spacing on the magnetic flux density and the AC internal resistance are obtained through the principle analysis. The coil parameters are adjusted through simulation experiments to improve the transmission efficiency. Then, the safety and stability of the device are ensured by temperature-power double closed-loop control. Then the closed-loop phase-shift control strategy is introduced to ensure that the system can output power stably in complex environments. In this paper, a low-power, safe and high-efficiency wireless energy transmission system is built, which provides a comprehensive and in-depth technical reference for the development of wireless power supply technology for implantable medical devices.

Analysis of Typical Principles and Popularisation Measures of Wireless Charging for Electric Vehicles

Currently, the tram and tanker markets are competing fiercely, and whether wireless charging for electric vehicles can be successfully promoted in the future depends largely on whether the tram market can gain an advantage. Wireless charging has developed to the point where the overall system is not too perfect, so optimising the power system and developing more efficient and safer wireless charging methods is necessary. This paper introduces the basic principles of wireless energy transmission technology and some of the wireless charging methods. The two wireless charging methods of microwave electric power wireless charging and magnetic coupling resonant wireless charging are introduced in principle and the advantages and disadvantages are compared. The safety of wireless charging is maintained, and today's lifestyle is analysed to provide different charging methods for different people. The paper also gives the corresponding measures for the various kinds of dangerous situations that may occur. Finally, the paper gives an outlook and conclusion for the future of wireless charging.

Efficiency Analysis of a Magnetic Resonance Coupled Wireless Power Transfer System

As the limitations of wired charging methods become more and more prominent, wireless charging as an emerging charging technology has been increasingly emphasized. Among these, resonant wireless charging technology has steadily advanced as circuit design and material research have progressed. This paper firstly introduces the background of wireless charging technology, its uses in daily life, and the significance of increasing wireless charging efficiency; then, this paper analyzes the major variables influencing the resonant wireless charging system's efficiency, including the circuit design, material selection, and system control strategy. By optimizing the coil design and adjusting the circuit parameters, the paper suggests multiple methods to raise the effectiveness of energy transfer. Finally, the paper verifies the effectiveness of these optimization strategies by establishing a simulation model, which offers theoretical justification for enhancing the wireless charging system's functionality in practical applications.

Simulation Research on Improving Wireless Charging Efficiency of Electric Vehicles

Accompanied by the continuous development and progress of science and technology worldwide, wireless energy transmission has become an increasingly important research focus for researchers in related fields. Wireless charging technology, with its advantages of safe operation, flexibility, convenience, and low maintenance costs, has received more and more attention and is one of the mainstream development trends of electric vehicles in the field of future power technology. The efficiency of wireless charging technology is an important factor affecting its promotion. This article summarizes and discusses the magnetic coupling resonance wireless energy transmission technology, analyzes the basic structure and working principle of the magnetic coupling resonance wireless energy transmission technology, and theoretically analyzes the magnetic coupling resonance wireless energy transmission circuit through a mutual inductance model. The circuit is built using the mutual inductance model in Multisim for simulation experiments to verify the correlation between wireless charging efficiency and circuit load and frequency. Plotted the correlation curve between wireless charging efficiency, circuit load, and frequency.

Effect of Coil Shape on the Critical Load Resistance of Frequency Splitting Phenomenon in Magnetic Resonance Wireless Power Transfer

Effect of Coil Shape on the Critical Load Resistance of Frequency Splitting Phenomenon in Magnetic Resonance Wireless Power Transfer

LC dynamic signal modeling and analysis of resonant frequency measurement error under rapid eye movements interference

Abstract LC resonant wireless passive intraocular pressure (IOP) sensors measure IOPs by mapping them to LC resonance frequencies. However, during the sweeping acquisition process of each LC signal frame, possible rapid eye movement (REM) can interfere with the wireless mutual inductance coupling, leading to the signal distortion and resulting in the error of resonance frequency measuring. Currently, there is a lack of modelling analysis of the errors generated by REM effect, resulting in an absence of guidance for reducing the impact. Therefore, here, we start from the perspective of the signal model and establish the LC dynamic signal model for sweeping acquisition. By means of the limit state analysis and Monte Carlo simulation, we analyze the influence of external REM parameters (including REM range and velocity) and internal parameters of the LC sensing system (including the quality coefficient of LC sensor, diameter, and number of turns of the reader coil, signal sweep acquisition speed and period) on the errors. We demonstrated theoretical relationship between the extreme errors with these parameters and verify it through a computer simulation. Based on the results, we propose to optimize the internal parameters of the LC sensing system to reduce the REMs effect on errors, safeguarding the quality of signal acquisition and improving the measurement accuracy.

Characterization of Abrasive Grain Signal of Oil Detection Sensor Based on LC Resonance Wireless Transmission

Friction in marine engineering machinery produces abrasive particles containing valuable information. By employing oil detection technology, we can analyze these particles to monitor and diagnose mechanical system faults. This paper introduces an inductive oil detection sensor and wireless signal transmission circuit. The sensor utilizes two opposing solenoid coils of the same specifications, with the detection coil connected to a chip capacitor to form an LC resonant unit. The designed wireless transmission circuit wirelessly transmits a sensing signal from a detection coil to a receiving coil to detect metal particles in oil. This paper deduces the sensor’s inductance principle and simulates the magnetic field distribution using finite element simulation software. Through experiments, the optimal excitation frequency, coil spacing, and oil sample flow path location were determined. The sensor successfully detected 55 μm iron particles and 138 μm copper particles in a 1 mm microfluidic channel. With its simple structure, distinct signal characteristics, and high sensitivity, the sensor is suitable for detecting metal abrasive particles in hydraulic oil, providing a new approach for wireless transmission in oil detection sensors.

Optimization of coupling coils for downhole magnetic resonance wireless energy transmission system

Abstract In drilling engineering, resonant wireless energy transmission technology can effectively solve the problem of frequent charging or battery replacement of cable-less electronic tools downhole. However, due to the narrow space, high temperature, and high pressure inside the oil well, as well as the complex environment where oil, water, gas, and sand coexist, the traditional coil shape is not applicable. Therefore, spiral coils with inner and outer casing are usually used. However, in practice, due to the complex downhole environment, resonant wireless energy transmission coupling devices often encounter difficulties when nested downhole, thus affecting the transmission efficiency. To solve these problems and ensure transmission efficiency, a novel coil coupling model is proposed in this paper, and the power and efficiency expressions of the coupled electrical energy transmission system are derived. Subsequently, the spiral cylinder and the novel coil were simulated and analyzed using COMSOL Multiphysics software. The experimental results show that the model maintains a good transmission efficiency and improves the nesting effect in a complex downhole environment. This study provides a valuable reference for the optimization and design of wireless energy transmission systems.

Application of wireless energy delivery system in automobile charging

With the popularity of electric vehicles, wireless charging technology has become a key area to address the convenience of charging electric vehicles. The aim of this study is to explore the principles of wireless energy transfer technology and its application in the field of electric vehicles. We first provide a background introduction to the field of electric vehicles, emphasising the importance of wireless charging technology. Subsequently, we delve into the charging and discharging characteristics of power batteries to better understand the need for energy transfer. Then, we carefully selected wireless charging methods suitable for electric vehicles and developed a corresponding wireless charging system architecture. In this paper, we also provide theoretical analyses of two major wireless energy transfer technologies, including electromagnetic coupled wireless energy transfer and resonant wireless energy transfer, as well as exploring the principles of RF wireless energy transfer technology. Finally, we propose an architecture for a static wireless charging system including five modules: pre-processing, transmission, reception, charging control and battery load. The contribution of this study is to provide an in-depth research and a comprehensive theoretical foundation for wireless charging technology in the field of electric vehicles, which helps to improve the charging efficiency and convenience of electric vehicles.

Modeling and Transmission Characteristics Study of a Resonant Underwater Wireless Electric Power Transmission System

Compared to the traditional wet-mate underwater power supply method, Magnetic Coupling Resonant Wireless Power Transfer (MCR-WPT) technology boasts advantages such as excellent insulation, high safety, and convenient operation, showing promising application prospects in the field of power supply for underwater vehicles and other mobile underwater devices. In order to explore the transmission characteristics of this technology underwater, this article first establishes a traditional mathematical model, and then modifies the underwater model through analysis of changes in coil self-inductance and mutual inductance, as well as the impact of eddy current losses. Using the modified mathematical model of the underwater MCR-WPT system, the transmission characteristics are analyzed, and simulations and experimental validations are performed using MATLAB R2022a software. In the study of frequency characteristics, it is found that the system operates optimally when both ends of the circuit work at the resonant state; that is, when finput = fresonance = 100 kHz, the output performance is at its best, and the optimal resonant frequency significantly improves power and transmission efficiency. When the input frequency is less than 87.3 kHz or greater than 122.9 kHz, the output power decreases to less than half of the maximum power. In the investigation of load effects, the optimal load for maximizing system output power was identified, but the load that maximizes transmission efficiency is different from this optimal load. This study provides strong theoretical support and guidance for improving the performance of underwater wireless power transmission systems.

Coil Parameter Optimization Method for Wireless Power Transfer System Based on Crowding Distance Division and Adaptive Genetic Operators

In a Magnetically Coupled Resonant Wireless Power Transfer (MCR-WPT) system, the magnetic coupling coil is one of the key factors that determines the system’s output power, transmission efficiency, anti-offset capability, and so on. This article proposes a coil parameter optimization method for a wireless power transfer system based on crowding distance division and adaptive genetic operators. Through optimizing the design of decision variables, such as the numbers of transmitting and receiving coil turns, the spacings between transmitting and receiving coil turns, the inner radii of the transmitting and receiving coils, and the vertical distance of the coil, the best transmission performance can be achieved. This study improves the NSGA-II algorithm through proposing a genetic operator algorithm for average crowding and high crowding populations based on adaptive operators, as well as a genetic operator algorithm for low crowding populations based on information entropy. These improved algorithms avoid problems inherent to traditional genetic operators such as fixed genetic proportions, do not easily cause the algorithm to fall into a local optimal solution, and show better convergence in the ZDT1–ZDT3 test functions. The optimization design method in this article is not only independent of commercial software such as ANSYS Maxwell 2021 R1, but can also significantly improve the calculation speed compared with traditional simulation software.

Synthesis and Control of a Three-Port LCL Resonant Wireless Power Transfer System for DC Energy Conversion Applications

Synthesis and Control of a Three-Port <i>LCL</i> Resonant Wireless Power Transfer System for DC Energy Conversion Applications

Modeling and analysis of magnetic resonance wireless transmission coil

Wireless transmission technology is a new type of power transmission technology with electric and magnetic fields as the medium. It has more advantages in transmission direction, transmission characteristics, security, and penetration. The model of a magnetically coupled resonant radio energy transmission system is designed. The main parameters such as resonance frequency and mutual inductance are considered comprehensively. The model is designed using the equivalent topological circuit structure of mutual inductance coupling. The equivalent parameters in the circuit topology can be affected by setting the size of the coil, the distance between the coils, the excitation size, and the high frequency. The structure parameters of the whole system are modeled and calculated by the Ansoft Maxwell software. At the same time, the influence on the power and efficiency of wireless power transmission is explored by several factors such as the coil diameter, the distance between the transmitting end and the receiving end, and the resonance frequency of the system, so as to achieve the purpose of verifying the technical characteristics of wireless power transmission. The key factors that may affect the transmission efficiency and power of the system are analyzed in detail by deriving the calculation model of transmission efficiency and power.

Research on MLD Modeling and Predictive Control of Magnetically Coupled Resonant Bidirectional WPT System

The recent studies on magnetically coupled resonant bidirectional wireless power transfer (MCR-BWPT) systems disregard the challenges posed by nonlinearity, discrete switching action, and hybrid properties within the system. This research focuses on the D-LCL resonant compensation topology MCR-BWPT system. The switch tube’s switching state dictates the division of various working modes and the determination of the switching conditions between them. The coupling relationship between the continuous dynamic characteristics of the system and discrete events and the constrained conditions of the system are derived. The Hybrid System Description Language (HYSDEL) is used to build the Mixed Logic Dynamic (MLD) model of the system. The MLD model is employed as the prediction model, and the hybrid model predictive controller of the MCR-BWPT system is constructed according to the quadratic performance index. Finally, to verify the accuracy of the MLD model and the feasibility of the control strategy, the simulation model of the MLD model is established in MATLAB/Simulink. The study’s findings show that, in terms of response time at system startup and power fluctuation suppression, the approach put forward in this research performs better than both the conventional bilateral dual-phase-shift control strategy and the PQ-based bilateral power control strategy. The MCR-BWPT system can operate more steadily now that PQ’s bidirectional power control technique is in place. The system’s forward and reverse transmission efficiency is increased by 0.29% and 0.32% compared to the conventional bilateral dual-phase-shift control approach; the increases are 0.28% and 0.09%, each compared to the bilateral power control strategy based on PQ.

Optimal Design of Relay Coil Inductance to Improve Transmission Efficiency of Four-Coil Magnetic Resonance Wireless Power Transmission Systems

Magnetic resonance wireless power transmission consists of a source coil and relay coil (transmission coil (Tx-coil), receiving coil (Rx-coil)). The relay coil is designed with windings and a series capacitor, which are resonant with the input voltage frequency. Magnetic resonant wireless power transmission by a relay coil enables the transmission of power from a few centimeters to several meters. Recently, research has been conducted on the shape and material of each coil to increase the transmission distance. However, limitations remain with respect to increasing the transmission distance. Specifically, the optimization of the electrical characteristics of the relay coil is necessary to increase the transmission distance and improve efficiency. In this study, we configured the inductance of the relay coil to be approximately 95 μH, 270 μH, and 630 μH. Accordingly, we designed the series capacitors to have the same resonant frequency and analyzed the transmission characteristics of each relay coil. We confirmed that as the inductance increased, the transmission efficiency increased by up to 10%. The relay coil was designed to have an inductance of approximately three to six times that of the source coil (load coil). Thus, the optimal design of the relay coil is believed to be the most efficient and economical coil design.

Research on Resonant Wireless Energy Supply Circular Reactive Shielding for Small Electronic Equipment

Research on Resonant Wireless Energy Supply Circular Reactive Shielding for Small Electronic Equipment

Power Receiving Unit for High-Power Resonant Wireless Power Transfer

A new power receiving unit (PRU) is proposed in this paper for resonant wireless power transfer (WPT), which is characterized by the capability of attracting high power from the power transmitting unit (PTU). The resonant WPT is designed for delivering the electrical power to the PRU attached on an electrical vehicle (EV) chassis 50 cm away from a PTU installed on the ground. The proposed PRU uses only the passive elements such as inductors, diodes, and capacitors, which need no initial power from the EV. It is then applicable for charging a battery to several hundred volts for even a first-time charging battery. For a resonant WPT at a switching frequency of 4 MHz, the proposed PRU behaves as a negative impedance converter (NIC) itself in the subharmonics of 4 MHz. The NIC effect plus the subharmonic oscillation causes an instability current charging the battery connected to the PRU. In this paper, we simulated the PRU and performed the experiment. The experiment demonstrated a battery charging of 150 W from 50 cm away using three D-mode GaN HEMT transistors via the instability current ramp. The power transfer efficiency (PTE) improved as the power delivered to the load (PDL) increased. The peak PTE was 65% in the present findings. The simulation analysis showed that the circuit allowed itself be used to much higher power transfer when it is implemented with more GaN HEMT transistors connected in parallel. The theoretical derivation of the PRU circuit is also used to support both the experimental and simulation results.