Equivalent Circuit and Calculation of Its Parameters of Magnetic-Coupled-Resonant Wireless Power Transfer PDF Download

Author: Hiroshi Hirayama
Publisher:
ISBN: 9789533078748
Category :
Languages : en
Pages :

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Author: Yiming Zhang
Publisher: Springer
ISBN: 9789811348983
Category : Technology & Engineering
Languages : en
Pages : 117

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This thesis focuses on the key technologies involved in magnetically coupled Wireless Power Transfer (WPT). Starting from the basic structures and theories of WPT, it addresses four fundamental aspects of these systems. Firstly, it analyzes the factors affecting transfer efficiency and compares various methods for reducing the working frequency. Secondly, it discusses frequency splitting and offers a physical explanation. Thirdly, it proposes and assesses three multiple-load transfer structures. Lastly, it investigates WPT systems with active voltage-source and current-source load. As such, the thesis offers readers a deeper understanding of WPT technology, while also proposing insightful new advances.

Author: Ali Agcal
Publisher:
ISBN:
Category : Technology
Languages : en
Pages :

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In this chapter, a wireless power transmission system based on magnetic resonance coupling circuit was carried out. Mathematical expressions of optimal coupling coefficients were examined with the coupling model. Equivalent circuit parameters were calculated with Maxwell 3D software, and then, the equivalent circuit was solved using MATLAB technical computing software. The transfer efficiency of the system was derived using the electrical parameters of the equivalent circuit. System efficiency was analyzed depending on the different air gap values for various characteristic impedances using PSIM circuit simulation software. Since magnetic resonance coupling involves creating a resonance and transferring the power without the radiation of electromagnetic waves, resonance frequency is a key parameter in system design. The aim of this research was to define the efficiency according to variations of coefficients in wireless power transfer (WPT) system. In order to do that, the calculation procedure of mutual inductance between two self-resonators is performed by Maxwell software. Equivalent circuit is solved in circuit simulator PSIM platform. The calculations show that using the parameters that are obtained by magnetic analysis can be used for the equivalent circuit which has the capability to provide the efficiency using electrical quantities. The chapter discusses the application of this approach to a coil excited by a sinusoidal voltage source and a receiver coil, which receives energy voltage and current. Both could be obtained to calculate the instantaneous power and efficiency. To do so, the waveforms for voltage and current were obtained and computed with the PSIM circuit simulator. As the air gap between the coils increased, the coupling between the coils was weakened. The impedance of the circuit varied as the air gap changed, affecting the power transfer efficiency. In order to determine the differences between the software programs, efficiency values were calculated using three kinds of software. And it is concluded that equivalent circuit analysis by means of numerical computing is proper to obtain the voltage and current waveforms. Correspondingly, transmission efficiency can be calculated using the electrical relations.

Author: Cheng Zhang
Publisher: Open Dissertation Press
ISBN: 9781361042915
Category : Technology & Engineering
Languages : en
Pages : 184

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This dissertation, "Directional and Omnidirectional Inductively Coupled Wireless Power Transfer Systems" by Cheng, Zhang, 張騁, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: This thesis presents the analysis and design methods of directional and omnidirectional inductively coupled wireless power transfer systems. Such system utilizes multiple coils to generate high frequency alternating magnetic fields in space and allows receivers to pick up power wirelessly in any position. The objective of optimization is to achieve the maximum power efficiency. Such kind of system allows the mobile devices to be continuously charged without staying on a fixed place. Self- and mutual- inductance values of the coils are critical parameters that affect the power efficiency of a wireless power transfer system. An improved numerical calculation method is proposed and is presented in this thesis. It combines the theory of partial equivalent element circuit (PEEC) and empirical equations for calculating certain types of straight conductors. The segmentation method to discretize the conductor is optimized and verified. The accuracy of the proposed method has been tested and compared to both theoretical equations and measurements of practical coils, and is proved to be accurate. The time-varying magnetic fields induced by the coils in a wireless power transfer system is the \transporter" of the energy. A time-efficient visualization method is proposed and is presented in this thesis. While commercial finite element analysis (FEA) software such as ANSYS Maxwell can perform transient analysis, the execution time is extremely long as the accuracy greatly depends on the simulation time steps and the number of iterations. The proposed method calculates the time-instant currents in coils with the derived mathematic model and then directly plots the time-varying magnetic fields. The execution time is shortened to a few of minutes on a desktop computer while the FEA solver takes a couple of hours on the same model. Several types of multiple-coil systems are analyzed with their magnetic field patterns. To transmit power to arbitrary directions, the magnetic field must be controlled with its directions. According to the principle of superposition, a three-orthogonal-coil transmitter structure is proposed. Several current control methods are discussed to achieve omnidirectional wireless power characteristics. One is a continuous scanning type current scheme. The receivers placed in the designated area can receive power with any locations and angles. Another one is a discrete scanning type. It can be used to detect the load position and therefore delivering power to the load with the maximum power efficiency of the overall system. Simulations and experiments have been carried out to verify the theory and they agreed well. While the aforesaid omnidirectional system adopts the special three-orthogonal-coil structure, the theory is generalized to arbitrary numbers of transmitters. It is proved by mathematical derivation that in a system with multiple transmitters and single receiver, there exists an optimal efficiency point when currents in the transmitter coils fulfill the certain relationships, regardless of the compensation scheme of the circuit, the use of magnetic materials and the shapes of the coils. An implementable method to calculate the optimal currents in a practical multiple-transmitter-single-receiver system is also provided. The generalized theory is verified by both simulations and experiments. Subjects: Electric power transmission

Author: Farid Jolani
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Sherif Hekal
Publisher: Springer
ISBN: 9811380473
Category : Technology & Engineering
Languages : en
Pages : 91

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This book addresses the design challenges in near-field wireless power transfer (WPT) systems, such as high efficiency, compact size, and long transmission range. It presents new low-profile designs for the TX/RX structures using different shapes of defected ground structures (DGS) like (H, semi-H, and spiral-strips DGS). Most near-field WPT systems depend on magnetic resonant coupling (MRC) using 3-D wire loops or helical antennas, which are often bulky. This, in turn, poses technical difficulties in their application in small electronic devices and biomedical implants. To obtain compact structures, printed spiral coils (PSCs) have recently emerged as a candidate for low-profile WPT systems. However, most of the MRC WPT systems that use PSCs have limitations in the maximum achievable efficiency due to the feeding method. Inductive feeding constrains the geometric dimensions of the main transmitting (TX)/receiving (RX) resonators, which do not achieve the maximum achievable unloaded quality factor. This book will be of interest to researchers and professionals working on WPT-related problems.

Author: Eugen Coca
Publisher: BoD – Books on Demand
ISBN: 9535124676
Category : Technology & Engineering
Languages : en
Pages : 142

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Book Description
Wireless power transfer techniques have been gaining researchers' and industry attention due to the increasing number of battery-powered devices, such as mobile computers, mobile phones, smart devices, intelligent sensors, mainly as a way to replace the standard cable charging, but also for powering battery-less equipment. The storage capacity of batteries is an extremely important element of how a device can be used. If we talk about battery-powered electronic equipment, the autonomy is one factor that may be essential in choosing a device or another, making the solution of remote powering very attractive. A distinction has to be made between the two forms of wireless power transmission, as seen in terms of how the transmitted energy is used at the receiving point: - Transmission of information or data, when it is essential for an amount of energy to reach the receiver to restore the transmitted information; - Transmission of electric energy in the form of electromagnetic field, when the energy transfer efficiency is essential, the power being used to energize the receiving equipment. The second form of energy transfer is the subject of this book.

Author: VARUN NAGOORKAR
Publisher:
ISBN:
Category : Wireless power transfer
Languages : en
Pages : 71

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Author: Zhigang Dang
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 72

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Wireless power transfer (WPT) technology has many potential applications such as consumer electronics and electric vehicles (EV). High transmission efficiency with long transmission distance and with large lateral misalignment is desired in WPT systems. Magnetic resonance coupled (MRC) WPT systems are suitable for midrange high efficiency wireless power transfer (WPT). In chapter 2, commonly used four-loop and two-loop MRC-WPT system configurations are analyzed and compared in terms of transmission efficiency and transmission distance first based on the simplified circuit model. An example symmetrical system simulation shows that with the same Tx, Rx, source and load, the four-loop system has longer transmission distance but with relatively lower transmission efficiency compare to the two-loop system. Then, A 3-D physical model of 5-turn, 400mm outer diameter spiral shape four-loop WPT system is developed and simulated by using ANSYS® HFSS® software package. Operation distance of 550mm with nearly constant maximum transmission efficiency of 92.3% is achieved. Laterally misaligned MRC-WPT system is investigated in chapter 3. The TEVD, a region on the transmission efficiency versus Rx lateral misalignment amount curve where the transmission efficiency first sharply drops from high efficiency down to zero and then recovers to a low efficiency value, is identified in this work. The identification of TEVD is verified by simulation results obtained from a developed ANSYS® HFSS® 3-D physical model. Simulation results of the ANSYS® HFSS® 3-D physical model with 5-turn, 60cm outer diameter spiral shape MRC-WPT system show that when the Rx is 30cm vertically away from the Tx, TEVD exists when the lateral misalignment value ranges from 50cm to 70cm. An elimination method for TEVD is proposed in chapter 4. The proposed method utilizes angular rotation of the Rx (or Tx) to eliminate the zero-coupling point which causes the TEVD and boosts the coupling coefficient such that the TEVD is eliminated and the high efficiency region is extended. ANSYS® HFSS® 3-D physical model simulation results show that the proposed method eliminates the TEVD and extends the high efficiency region from 50cm lateral misalignment (83.3% of the Rx diameter) to 70cm lateral misalignment (117% of the Rx diameter). Chapter 5 summarizes the thesis conclusions and sheds the light on future work.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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A new method of electrical wireless power transfer has been parameterized and experimentally verified for a variety of size-scales and applications. The main distinction between this and previous methods of wireless power transfer is the nature of the coupling mechanism, which is a magnetic interaction between synchronized, rotating, permanent magnets. Its main components can be viewed as equivalent to an electric motor, a magnetic gear, and an electric generator. Its performance parameters such as power, range and efficiency are within the same order of magnitude as previously known resonant inductive power transfer devices. However, it has the distinct benefit of operating at much lower operating frequencies. A theoretical model of the new system has been developed with sufficient detail to characterize and predict experimental behavior of various sizes. The theoretical treatment has been divided into three main interactions: the motor, the generator and the magnetic gear. The mechanism for operation, as well as a model for efficiency and losses have been developed for each interaction. The viability of this new method of wireless power transfer was experimentally verified for two size-scales. The larger size-scale achieved 1.6 kW of power transfer with 15 cm separation. The main target applications of this size-scale are for wireless charging of electric vehicles and industrial applications. The smaller size-scale achieved 60 W of power transfer with 10 cm separation. The main target applications of this size-scale are for powering medical implants and consumer electronics. Both size-scales achieved efficiencies in the range of 81%, and the operating frequency did not exceed 150 Hz. The design and construction of the devices are outlined for both size-scales. Misalignment tolerance between the transmitting device and the receiver device was experimentally investigated, and related control schemes for managing the power transfer were implemented and tested. Additi.