Magnetic Coupling Wireless Power Transfer Research Articles

Analysis and Design of Self-Oscillating Magnetic Coupling Wireless Power Transfer Systems

Analysis and Design of Self-Oscillating Magnetic Coupling Wireless Power Transfer Systems

A Multirelay Magnetic Coupling Wireless Power Transfer System With Hybrid Output Characteristics

A Multirelay Magnetic Coupling Wireless Power Transfer System With Hybrid Output Characteristics

Comparative Analysis of SS, SP, PP and PS Topologies for Magnetic Coupled Wireless Power Transfer System Composed of the Negative Resistor

In recent years, the concept of the negative resistor (NR) has been proposed and applied in the magnetic coupled wireless power transfer (MC-WPT) system to improve the stability of power transfer. However, it remains a fundamental challenge to find the characteristic differences and applications of the four basic NR-based MC-WPT topologies. In this paper, the circuit models of the four basic NR-based MC-WPT topologies: series-series (SS), series-parallel (SP), parallel-parallel (PP), and parallel-series (PS) are established, and their characteristics are analyzed and compared by using circuit theory, which enables engineers to determine and select topologies to suit different applications and requirements. Theoretical analysis shows that the compensation methods of the transmitter and receiver of the NR-based MC-WPT system would affect the operating frequency and output characteristics of the system. Moreover, by comparative analysis, the conditions and applicable ranges for a stable output of different topologies were provided. Finally, the experimental prototypes are set up by using the power electronic inverter and operational amplifier, and the voltage gain ratios of the four basic NR-based WPT topologies under the variations of transfer distance and load are observed. The experimental results validate the correctness of the theoretical analysis.

A secured wireless charging scheme with data transmission

This research task proposes a magnetic resonant coupling wireless power transfer(MRC-WPT) scheme for electric vehicles, which realizes secure data communication between the wireless charging station and the electric vehicle using binary phase shift-keying (BPSK) data transmission, thereby waving any radio frequency(RF) communication links. The secondary side is designed to accept power, while it transmits data back to the primary side simultaneously. The BPSK design ensures data transmission robustness to against disturbance interference. The data are encrypted by the user's biometric features for information security. The magnetic resonance performs better than that of the traditional magnetic induction in the power transmission efficiency against coil misalignments. With the Internet of Thing(IOT) architecture, the encrypted data can be stored and retrieved via the cloud server.

Design of anti-misalignment PCB coil for wireless power transfer

This paper focuses on the problem of the non-uniform magnetic field distribution in short-distance magnetic coupled wireless power transfer (MC-WPT) systems, which causes the transfer power and power transfer efficiency to decrease when the transmitter and receiver coils are offset. At first, the distribution law of the magnetic field generated by the printed circuit board (PCB) coil is studied. A new method is proposed to design the transmitter coil, which combines a genetic algorithm (GA) with a partial element equivalent circuit (PEEC). The appropriate turn radii are first obtained by the GA, and the quality factor is further evaluated by the PEEC to select the optimal coil turns. Finally, the PCB coils with uneven pitches are fabricated, and experiments are carried out on an MC-WPT system. The effective power transfer area is expanded noticeably and the high efficiency of the system remains stable, which is very useful to provide a wider working space and steady wireless energy supply for mobile objects.

Analysis of four-coil magnetic resonance coupling wireless power transfer system based on LCC-SSS compensation network

The classical four-coil magnetic resonance coupling wireless power transfer (MRC-WPT) system usually uses a Series-Series-Series-Series (SSSS) compensation network, while its input series resistance and load resistance are designed approximately. I It is a remarkable fact that the power loss of the input series resistance adversely affects the overall efficiency of the WPT system, but the absence of the resistance will lead to the input current surge when the four-coil system is detuned, which is not conducive to the stability of the security of the circuit system. With this aim in mind, an Inductance-Capacitance-Capacitance-Series-Series-Series (LCC-SSS) compensation network is proposed in this paper, which removes the input series resistance to improve the total efficiency on the premise of ensuring the reliability of the system. Relation between transmission efficiency, transmission power and parameters of LCC-SSS compensation network, the parametric calculation method of LCC compensation network is presented. Finally, the experimental results compare the transmission power and efficiency of the two compensation networks and verify the correctness of the LCC-SSS compensation network.

Communication-Less Receiver-Side Resonant Frequency Tuning for Magnetically Coupled Wireless Power Transfer Systems

Compensating for deviations in the resonant frequency is crucial in magnetic resonance coupling wireless power transfer (WPT) systems. Thus, this study proposes a communication-less receiver-side resonant frequency-tuning scheme that compensates for the reactance in the receiver without communicating with the transmitter. The proposed scheme comprises an inductor-capacitor-capacitor compensation topology at the transmitter and a half-bridge circuit at the receiver, whose operating phase is set to be orthogonal to the receiver current. Resonant frequency tuning can be achieved by adjusting the DC voltage applied to the half-bridge circuit to maximize the power received at the load. The reactance compensation ability of the proposed scheme is analyzed through experiments on a 200 kHz WPT system. When the secondary capacitance deviated from –20% to +20%, the efficiency degradation was maintained within 6.7% with the proposed scheme, whereas the efficiency degraded by up to 33.3% without compensation.

A Dual-Frequency Dual-Load Multirelay Magnetic Coupling Wireless Power Transfer System Using Shared Power Channel

Aiming at the power supply solution of online monitoring equipment for high-voltage transmission lines, a dual-frequency dual-load multirelay magnetic coupling wireless power transfer (MC-WPT) system using a shared power channel has been proposed. The proposed MC-WPT system provides the selective power distribution for different loads and has the constant current output characteristic. First, a dual-frequency inverter is introduced to provide the ac voltage of two frequencies. The compensation network that includes the band-stop filter can reduce the cross interference of the nontarget frequency from another power channel. Second, the system is modeled and analyzed based on the quadratic eigenvalue problem. Considering the cross-coupling mutual inductance, operating frequencies that make the system have constant current output characteristics are obtained. Finally, three evaluation indices are proposed: average current gain, load-independent index, and average sensitivity index of operating frequencies. Optimized operating frequency is selected according to these evaluation indices. The experimental results verify constant current output characteristics and the selective power distribution of two power channels.

Analysis and Design of Ideal Transformer-Like Magnetic Coupling Wireless Power Transfer Systems

An ideal transformer-like (IT-like) magnetic coupling wireless power transfer system is proposed in this article, which can achieve a large constant power and efficiency output over a wide transfer range. First, the general circuit model is presented along with the analysis of fundamental and harmonic current characteristics. Then, the IT-like operation mechanism with a fixed desired secondary-primary current amplitude ratio independent of mutual inductance is proposed, based on which the transfer range capable of both power and efficiency is greatly improved. The corresponding parameter criteria and implementation methods, including the zero-phase-angle mode and the zero-voltage-switching mode are derived and verified in a practical prototype. The experimental results show that the proposed system can take the output power, transfer efficiency, transfer range, and current characteristic into account at the same time, with strong position robustness and high tolerance to variable couplings.

5G Magnetic Resonance Coupling Planar Spiral Coil Wireless Power Transfer

Wireless Power Transfer in the 5G frequency band is the most promising technology to power up ubiquitous small electronic devices as well as IoT devices. A strongly coupled magnetic resonance WPT technique that focuses on near-field electromagnetic energy has been proposed in this paper. However, most Magnetic Resonance Coupling Wireless Power Transfer (MRC WPT) applications have been designed in kHz and MHz frequency spectrum. This paper demonstrates Planar Spiral Coil Magnetic Resonance Coupling (PSC MRC) WPT designs at 5G (GHz) frequencies. Also, the transformation technique of the low frequency (kHz and MHz) magnetic resonance circuit model equations to high frequency (GHz) circuit model equations to achieve a high-efficiency power transfer. PSC MRC WPT designs structure antennas are designed at 3.4 - 3.5 GHz in the form of circular and square shapes with 1 turn coil. The proposed antenna structures are firstly being optimized in a full-wave electromagnetic simulator, CST Microwave Studio to resonate at the 3.4 - 3.5 GHz band. Then, the close-loop equations to determine the efficiency of 5G Magnetic Resonance Coupling Planar Spiral Coil Wireless Power Transfer is designed. Lastly, the results are compared with the simulation and calculated parts. The highest efficiency of the PSC MRC circular antenna is 31.58 % when the distance is at 2 mm, and 31.26 and 31.02 % when the distance is at 3 and 4 mm, respectively. The efficiency of circular PSC MRC is found to be 25 % better than the efficiency of square shape design. HIGHLIGHTS IoT devices need to be charged and maintained as the network system has massive numbers of sensors. Wireless power transfer is a promising technology to power up IoT devices This paper proposed, a WPT technique based on strongly coupled magnetic resonance which focuses on the near-field electromagnetic energy. This technique can extend the distance of the power transfer between the transmitter and the receiver The transformation technique of the low frequency (kHz and MHz) magnetic resonance circuit model equations to high frequency (GHz) circuit model equations to achieve a high-efficiency PSC MRC WPT design structure is introduced in this paper This novel technique can be applied to effectively design PSC MRC Antenna WPT for 5G applications. Most reported Magnetic Resonance Coupling Wireless Power Transfer (MRC WPT) applications have been designed in kHz and MHz frequency spectrum GRAPHICAL ABSTRACT

Research on cross-decoupling of multirelay magnetic coupling wireless power transfer system

Research on cross-decoupling of multirelay magnetic coupling wireless power transfer system

Matching network design for input impedance optimization of four-coil magnetic resonance coupling wireless power transfer systems

Matching network design for input impedance optimization of four-coil magnetic resonance coupling wireless power transfer systems

Analysis of Symmetric Two and Four-coil Magnetic Resonant Coupling Wireless Power Transfer

This study examined the efficiency of power transfer for two-coil and four-coil spiral magnetic resonant coupling wireless power transfer (WPT) using distance to coil diameter (D/dm) ratio and reflection coefficient, S21 value. Adding resonators reduced the total resistance in the two-coil WPT system while increasing the S21 values of the whole system. A same-size spiral coil was proposed for the system and simulated using computer simulation technology (CST). A prototype with similar specifications for a four-coil design was implemented for verification. The proposed method yielded an optimal efficiency of 76.3% in the four-coil system, while the two-coil WPT yielded a 23.2% efficiency with a 1.33 D/dm ratio.

Magnetic resonance coupling wireless power transfer for green technologies

Wireless <span>power transfer (WPT) is a technology that is considered the focus of scientists' attention for its development and creation to be compatible with many devices that are used today and also consider one of the green technology apps which means any technology can reduce the effect of people on the environment which is today grow continuously. In this paper, a wireless power transfer for a mobile charger had been discussed to get a maximum power and efficiency power transfer. WPT is considered as a reliable technology, efficient, fast, not using wires, and can be used for short and long-range. There are three methods for WPT, electromagnetic induction, magnetic resonance coupling, and radio waves which are classified by the distance that sends the power. Magnetic resonance coupling is the method that has been focused on in this paper because of compatibility with short or medium distances as battery chargers which depend on the magnetic field to transfer power without wires that can protect devices from damages and heating. As result the effect of distance on efficiency has been discussed with reached to nearer distance can improve efficiency however by using magnetic resonance technique, acceptable efficiency can be obtained with appropriate distance.</span>

Research on parameter identification and phase-shifted control of magnetically coupled wireless power transfer system based on Inductor–Capacitor–Capacitor compensation topology

In the practical applications of magnetically coupled wireless power transfer (MC-WPT) system, mutual inductance and load may change. In view of this situation, a parameter identification method, which based on the hybrid algorithm of particle swarm optimization algorithm and genetic algorithm, for Inductor–Capacitor–Capacitor Series( LCC-S) system under phase-shifted control is proposed in this paper. The method only needs the current sampling data of the primary side. By configuring the parameters of the serial genetic particle swarm optimization (GA-PSO) algorithm and planning its operation process, mutual inductance and load identification is achieved at any phase-shifted angle. Then the phase-shifted angle is adjusted according to the identification results, and the constant output voltage control of the system is realized. The accuracy of the parameter identification method and phase-shifted constant output voltage control is verified by simulation and experiment. The maximum relative error of mutual inductance identification is 3.17%. And the maximum relative error of the load identification results is 5.87%. The maximum error between the output voltage and the set value is 3.5%.

Wireless power transfer system based on LCC/LCL-S variable structure with constant output power

In magnetic coupling wireless power transfer system, the relative position of power transfer coils may change during the operating condition. In order to solve the mutual inductance variation caused by the movement of coils, increase the anti-offset capability of the system to achieve constant power output, a variable structure is proposed in this article. Build the mathematic models of LCC-S and LCL-S structures and analyze the expressions of output power and efficiency in two structures. Design the switching condition, the relationship between coupling coefficient at switching point and parameter setting of capacitor array is obtained with the same input voltage and constant output power. The coupling coefficient range is estimated by output open circuit voltage with a small-voltage input, and the controlling strategy is put forward. Analyze the efficiency of variable structure and build the loss model. It is proved that the switching and input harmonic loss can be reduced by using LCC/LCL-S structure, while the transfer efficiency can be improved through the structure switching between two structures. The simulation results show that the variable structure can effectively reduce the variation range of input voltage and decrease the total harmonic distortion (THD) of input voltage by 46.6%, and keep THD of input current small in a wide range of coupling coefficient.

Wireless power transfer system with enhanced efficiency by using frequency reconfigurable metamaterial

The wireless power transfer (WPT) system has been widely used in various fields such as household appliances, electric vehicle charging and sensor applications. A frequency reconfigurable magnetic resonant coupling wireless power transfer (MRCWPT) system with dynamically enhanced efficiency by using the frequency reconfigurable metamaterial is proposed in this paper. The reconfigurability is achieved by adjusting the capacitance value of the adjustable capacitor connected in the coil of the system. Finite element simulation results have shown that the frequency reconfigurable electromagnetic metamaterial can manipulate the direction of the electromagnetic field of the system due to its abnormal effective permeability. The ultra-thin frequency reconfigurable metamaterial is designed at different working frequencies of 14.1 MHz, 15 MHz, 16.2 MHz, 17.5 MHz, 19.3 MHz, 21.7 MHz and 25 MHz to enhance the magnetic field and power transfer efficiency (PTE) of the system. Frequency reconfigurable mechanism of the system with the frequency reconfigurable metamaterial is derived by the equivalent circuit theory. Finally, further measurement which verifies the simulation by reasonable agreement is carried out. PTE of the system by adding the metamaterial are 59%, 73%, 67%, 66%, 65%, 60% and 58% at different working frequencies. PTE of the system with and without the metamaterial is 72% and 49% at the distance of 120 mm and the frequency of 15 MHz, respectively.

Improvement of transmission efficiency by using annular array metamaterial for magnetic coupling wireless power transmission system

Recently, the magnetic coupling wireless power transfer technology has been attracting a lot of attention and is expected to have a wide range of applications in the electrical equipment around us. On the other hand, there have been reports on the application of metamaterials for the purpose of improving antenna gain and suppressing mutual coupling between antennas, and this study aim applying this technique to the magnetic coupling wireless power transfer system. In this paper, a magnetic wall by meta material suitable for a magnetic coupling wireless transfer system is proposed and its effect is demonstrated experimentally.

Analysis and Design of EIT-Like Magnetic Coupling Wireless Power Transfer Systems

In order to improve the effective transfer range and then enhance the interoperability of magnetic coupling wireless power transfer (MC-WPT) systems, an electromagnetically induced transparency (EIT)-like MC-WPT system is proposed in this paper, which can maintain a reasonable level of power and efficiency over a wide range of transfer distance. Firstly, the circuit model of the tri-coil MC-WPT system is presented along with several key concepts, including EIT mechanism and eigen parameters. Then the energy efficiency characteristic of the system in eigen state is investigated, based on which the energy efficiency improvement principle and corresponding parameter design condition of the EIT-like mechanism are derived. Finally, practical systems are designed, simulated and measured to show the accuracy and effectiveness of the proposed method. The simulation and experimental results show that, with the proposed method, the effective transfer range that takes into account both output power and transfer efficiency is greatly improved. The method is particularly suitable for the design of electric vehicle charging piles, based on which the effective charging of vehicles with different chassis heights on a charging pile can be achieved.

Finite-control-set model predictive control for magnetically coupled wireless power transfer systems

Output voltage control is an important subject in magnetically coupled wireless power transfer (MC-WPT) applications. Conventional control methods for MC-WPT systems use the PI controller. However, this method suffers from three issues: time-consuming tuning work of the PI parameters, increased control complexity due to the needs of the modulator, and poor dynamic performance. To provide an attractive alternative to the PI controller, a novel output voltage regulation method based on finite-control-set model predictive control (FCS-MPC) has been proposed for a MC-WPT system. The proposed method has inherent advantages such as a very intuitive concept, no need for a modulator, and fast dynamic response. Moreover, it can achieve soft switching by constructing pulse-density-modulation-based voltage pulse sequences as the control set. The design and implementation of the proposed controller are discussed in this paper. The proposed control method has been tested on a series-series-compensated MC-WPT system, and experimental results demonstrate the effectiveness of the proposed control method in comparison with PI control methods.