Resonant Inductive WPT Link in MISO Configuration (original) (raw)
Energies
In this paper a general-purpose procedure for optimizing a resonant inductive wireless power transfer link adopting a multiple-input-multiple-output (MIMO) configuration is presented. The wireless link is described in a general–purpose way as a multi-port electrical network that can be the result of either analytical calculations, full–wave simulations, or measurements. An eigenvalue problem is then derived to determine the link optimal impedance terminations for efficiency maximization. A step-by-step procedure is proposed to solve the eigenvalue problem using a computer algebra system, it provides the configuration of the link, optimal sources, and loads for maximizing the efficiency. The main advantage of the proposed approach is that it is general: it is valid for any strictly–passive multi–port network and is therefore applicable to any wireless power transfer (WPT) link. To validate the presented theory, an example of application is illustrated for a link using three transmitt...
Optimal Terminations for a Single-Input Multiple-Output Resonant Inductive WPT Link
Energies
This paper analyzes a resonant inductive wireless power transfer link using a single transmitter and multiple receivers. The link is described as an (N+1)–port network and the problem of efficiency maximization is formulated as a generalized eigenvalue problem. It is shown that the desired solution can be derived through simple algebraic operations on the impedance matrix of the link. The analytical expressions of the loads and the generator impedances that maximize the efficiency are derived and discussed. It is demonstrated that the maximum realizable efficiency of the link does not depend on the coupling among the receivers that can be always compensated. Circuital simulation results validating the presented theory are reported and discussed.
A Comparison of Analytical Models for Resonant Inductive Coupling Wireless Power Transfer
— Recent research in wireless power transfer (WPT) using resonant inductive coupling has demonstrated very high efficiencies (above 40%) at large distances compared to the antenna dimensions, which has exponentially increased the number of potential applications of WPT. Since resonant inductive coupling is a very multidisciplinary field, different approaches have been proposed to predict the behaviour of these systems from physical theory of resonators, reflected load theory and the circuit point of view. However, the relation between these methods is still obscure. In this article, we compare the results of these models to find the efficiency of a Resonant Inductive Coupling WPT system under Steady-State sonditions and to analyze the relation between the optimal load values obtained from this perspectives and the ones obtained using impedance matching techniques.
Resonant Configuration Topology Exploration for Inductive Link Power Transfer
Indonesian Journal of Electrical Engineering and Computer Science, 2018
This paper investigates the performance of circuit topology used in wireless power applications to optimize the level of maximum efficiency. We analyse the series and the parallel resonant topologies for use in an inductive coupling link to derive power transfer efficiency expressions verified using MATLAB. We look into the two topologies into the link under resonant conditions for selectively supplying the device with power. The results are obtained analytically which are verified subsequently by MATLAB simulation. We then analyse the links to see how maximum power transfer efficiency for a given pair of coils can be achieved. The topology at a given tuning frequency is used for powering a selected resistive load. The method is presented using a given pair of coils simulated and the results agree well with the theoretical explanation and derivations.
A Power Converter Decoupled from the Resonant Network for Wireless Inductive Coupling Power Transfer
Energies, 2019
In a traditional inductive coupling power transfer (ICPT) system, the converter and the resonant network are strongly coupled. Since the coupling coefficient and the parameters of the resonant network usually vary, the resonant network easily detunes, and the system efficiency, power source capacity, power control, and soft switching conditions of the ICPT system are considerably affected. This paper presents an ICPT system based on a power converter decoupled from the resonant network. In the proposed system, the primary inductor is disconnected from the resonant network during the energy injection stage. After storing a certain amount of energy, the primary inductor is reconnects with the resonant network. Through this method, the converter can be decoupled from the resonant network, and the resonant network can be tuned under various coupling coefficients. Theoretical analysis was explored first. Simulations and experimental work are carried out to verify the theoretical analysis...
Development of a Wireless Power Transfer System using Resonant Inductive Coupling
— Access to power is a fundamental requirement for the effective functioning of any electrical/electronic circuit. The conduit of transfer of power can be either physical (wires, cables etc.) of non-physical (i.e. wireless). Wireless power transfer is a broad term used to describe any means used to transmit power to electricity dependent systems and devices. In this paper, a wireless power transfer system is developed to provide an alternative to using power cords for electrical/electronic devices. With this technology, challenges like damaged or tangled power cords, sparking hazards and the extensive use of plastic and copper used in cord production are resolved and also the need for batteries in non-mobile devices is eliminated. In this system, electromagnetic energy is transmitted from a power source (transmitter) to an electrical load (receiver) via resonant inductive coupling. The performance achieved is a good indication that power can still be transmitted over a medium range. In addition, possible ways of improving the efficiency of the system are discussed.
Development of a Wireless Power Transfer System using Resonant Inductive Coupling Conference
2017
Access to power is a fundamental requirement for the effective functioning of any electrical/electronic circuit. The conduit of transfer of power can be either physical (wires, cables etc.) of non-physical (i.e. wireless). Wireless power transfer is a broad term used to describe any means used to transmit power to electricity dependent systems and devices. In this paper, a wireless power transfer system is developed to provide an alternative to using power cords for electrical/electronic devices. With this technology, challenges like damaged or tangled power cords, sparking hazards and the extensive use of plastic and copper used in cord production are resolved and also the need for batteries in non-mobile devices is eliminated. In this system, electromagnetic energy is transmitted from a power source (transmitter) to an electrical load (receiver) via resonant inductive coupling. The performance achieved is a good indication that power can still be transmitted over a medium range. I...
Multi-band design of matched wireless power transfer links
2014 IEEE Wireless Power Transfer Conference, 2014
In magnetic resonant wireless power transfer the free-space part of the link can be represented as coupled inductances. By adding appropriate series capacitances (so as to obtain resonance) only an immittance inverter is left. When the value of the immittance inverter is selected equal to the load impedance, no further elements are necessary to accomplish matching. In addition, by considering lossy coupled inductances, it is possible to accurately define the reference impedances which realize the maximum efficiency for the wireless link. By using this principle for different frequencies we can realize a network capable of achieving maximum efficiency for different values of coupling at different frequencies. Numerical and experimental verification of the proposed approach are also presented.
Rigorous design of matched wireless power transfer links based on inductive coupling
Radio Science
This paper focuses on a near-field wireless power transmission link consisting of two magnetically coupled inductances. The case of a resonant coupling realized by adding appropriate compensating capacitances is solved. By using a network formalism, the link is modeled as a two-port network and rigorously analyzed in the case where both the input impedance and the load are specified. In particular, it is demonstrated that there is just one optimum design of the network that allows maximizing both the efficiency and the active power on the load. Closed-form design formulas for the optimum design are presented and validated by circuital simulations.
Characterization of resonant coupled inductor in a wireless power transfer system
Journal of Electrical Systems and Information Technology, 2024
Wireless power transfer (WPT) has garnered significant interest as a potentially transformative technology in the energy sector, as it presents a novel approach to powering and charging devices. The functionality of this technology is predicated upon the utilization of electromagnetic coupling to facilitate the wireless transmission of energy between two entities. Despite the considerable potential, wireless power transfer (WPT) faces significant obstacles that restrict its practical feasibility. One notable challenge that arises is the decrease in power transfer efficiency as the distance between the transmitter and receiver increases. Moreover, the wireless power transfer (WPT) technology is further limited by its reliance on accurate alignment between the transmitting source and the receiving device, thereby posing challenges for its practical implementation. The issues present substantial obstacles to the widespread commercialization of wireless power transfer (WPT). This study seeks to improve the efficacy of power transfer by optimizing the resonance frequency of the power transfer in response to the challenges. By systematically manipulating various parameters including coil dimensions, input voltage levels, and operational frequency, a novel approach is proposed to enhance the efficiency of power transfer. The study additionally offers valuable insights regarding the correlation between the distance separating the coils and the efficiency of power transfer. The findings of this study offer a thorough empirical analysis and are supported by a strong theoretical framework, resulting in a substantial coefficient of determination (R 2 = 0.937118). This finding suggests that the linear regression model under consideration could account for approximately 93.7118 percent of the variability observed in the distance. The findings of this study establish a pathway toward enhanced and feasible wireless power technology, thereby establishing a robust basis for the prospective commercial implementation of wireless power transfer (WPT) systems.
Design and Analysis of Resonant Wireless Power Transfer System
MATEC Web of Conferences, 2018
In this paper, the modelling and analysis of resonant wireless power transfer (RWPT) system are carried out by using circuit theory. Equations of the efficiency and frequency are derived for basic series-series circuit topology and series-parallel-mixed circuit topology. The designed model uses the series-parallel-mixed topology. The model is tested for two different peak-to-peak voltage levels including 20 V and 40 V. The achieved efficiency at 20 V is 49.10% and at 40 V is 49.52% approximately. The modelling is performed by using advanced design system (ADS) high frequency design software. In addition, an overview of currently available wireless power transfer (WPT) technologies and the recent study on inductive wireless power transfer (IWPT) and resonant wireless power transfer (RWPT) systems is also presented.
Aeu-international Journal of Electronics and Communications, 2019
This paper is a thorough theoretical analysis of a two-coil wireless power transfer system (WPTS) configured in series with a focus on power optimization rather than maximizing transmission (link) efficiency. Different definitions of the system efficiency in the pertaining literature are distinguished and clarified. The frequency splitting phenomenon is precisely explained, and furthermore, the analytical solutions are derived based on analysis of the input impedance. The effects of this behavior on the power transfer to a load resistance are discussed. Various aspects of the power optimization problem are explored. In particular, for the case when the system is driven at the resonance frequency, (i) the explicit expression of the optimal coupling factor between the two coils for a given load, and (ii) the optimum power with respect to the load are provided. The impedance matching methods using different circuit topologies are analytically or numerically investigated, revealing that the drive frequency can be arbitrarily chosen and not necessarily equal to the resonance frequency. This provides more options for exciting the system apart from the resonance condition, without compromising the delivered power. A comparison between optimization techniques is given in terms of the coupling factor k, showing that the bi-conjugate matching with Π − networks results in the maximum generated power and the transducer power gain (i.e., defined by the ratio between the received power and the power available from the source), which reaches 80 % at k = 84.4 × 10 −3 , for example.
Wireless power transfer system based on magnetic resonant coupling with directional coupler
2017
This paper presents an investigation of a new wireless power transmission (WPT) system based on magnetic resonant coupling with introduced directional or additional coupled inductances. Two coupled resonant circuits reveal two resonant frequencies with highest efficiency of power transfer. It is suggested that a directional coupler or two additional coupled inductances can be used to track these resonant frequencies. According to the observed reflection frequency characteristic the frequency of the PWT system operation can be adjusted. Moreover, the resonant frequency of the transmitter side can be changed assuring high efficiency of the system in a wide range of coupling coefficients i.e. distances between transmitter and receiver.
Wireless Power Transfer Systems Optimization Using Multiple Magnetic Couplings
Electronics, 2021
Multiple magnetic couplings used to increase the link distance in wireless power transfer systems (WPTSs) are not new. An efficient power transfer in conditions of an extended link distance requires a series connection of the intermediate coils. However, all four connections of the emitter and receiver coils are equally possible. This present paper conducts an extensive analysis of WPTSs utilizing three magnetic couplings. The type of connection of the emitter and receiver coils represented the criterion utilized for the WPTS optimization assessment. The first step requires the determination of the schematic of the sinusoidal equivalent circuit. Then, one synthesizes the functions describing the system performances (e.g., the amount of delivered active power or efficiency) by applying the entirely symbolic and or the hybrid symbolic-numerical formalism. The output of such functions consists of appropriate representation in the frequency domain, based upon Laplace state variable equa...
An Innovative Design of Wireless Power Transfer by High Frequency Resonant Coupling
2015
The main objective of this paper is to develop a concept of transferring power without use of any wires. The concept is based on low frequency to high frequency conversion. High frequency power is transmitted between inductor through air core. By using two self resonating coils, non-radiative power is transmitted over distances upto three times the radius of the inductor coils.
A Review of Wireless Power Transfer System via Magnetic Resonant Coupling
International Journal For Scientific Research and Development, 2013
recently, an efficient mid-range wireless power transfer that uses magnetic resonant coupling, WiTricity, was proposed, and has received much attention due to its practical range and efficiency. By referring studies the resonance frequency of the antennas changes as the gap between the antennas change. To achieve maximum power transmission efficiency, the resonance frequency has to be fixed within the particular band. In this paper, the possibility of using impedance matching (IM) networks to adjust the resonance frequency of a pair of antennas at 13.56MHz is studied. Experiments also show that IM can be achieved just by observing and minimizing the reflected wave.
Rigorous network modeling of magnetic-resonant wireless power transfer
Wireless Power Transfer, 2014
Magnetic-resonant wireless power transfer (MRWPT) has been typically realized by using systems of coupled resonators. In this paper, we introduce a rigorous network modeling of the wireless channel and we introduce several viable alternatives for achieving efficient MRWPT. Ideally, the wireless channel should realize a 1:n transformer; we implement such transformer by using immittance inverters. Examples illustrate the proposed network modeling of the magnetic-resonant wireless power channel.
Wireless power transfer between one transmitter and two receivers: optimal analytical solution
Wireless power transfer, 2016
This paper focuses on non-radiative wireless power transfer implemented by means of a resonant magnetic coupling. The case of one transmitter and two receivers is considered and a rigorous analytical procedure is developed demonstrating that maximum power transfer or maximum efficiency can be achieved by appropriately selecting the load values. Both cases of coupled and uncoupled receivers are solved; closed formulas are derived for the optimal loads, which maximize either power or efficiency. It is shown that the resistances that realize maximum power transfer are always greater than the resistances that realize maximum efficiency. According to this observation, an optimal range of operation for the load resistances is also determined. Furthermore, it is demonstrated that in the case where the receivers are coupled the introduction of appropriate compensating reactances allows retrieving the same results corresponding to the uncoupled case both for powers and efficiency. Theoretical data are validated by comparisons with numerical results.