Contactless Power Transfer System Research Articles

Selection of semiconductor switches in high frequency inverter fitted contactless power transfer system for reducing input current distortion

This paper investigates the selection of semiconductor switches used in contactless power transfer (CPT) system. In the present paper a single phase high frequency full bridge inverter using different semiconductor switches like IGBT, MPOSFET and GTO has been considered. Harmonic injection in input current of the inverter for different semiconductor switches has been analyzed using PSIM software. The THD of input current of the inverter for the particular switching device has been determined by using Fourier Transforms. It has been observed that THD in case of the IGBT is minimised.

A Method for Designing a High‐Power Contactless Power Transformer Considering Reactive Power

SUMMARYProblems in high‐power contactless power transmission systems using series and parallel resonance capacitors arise from the maximum voltage limit of the series capacitor due to high reactive power. In this study, the characteristics of the reactive power are analyzed using an equivalent circuit and a contactless power transfer system is designed with the reactive power characteristics taken into consideration. The self‐inductance and the frequency can be used to determine the distribution of reactive power on the primary side and the secondary side. In addition, the optimal winding number, size of the coil, and the appropriate frequency are investigated through electromagnetic field analysis.

Analysis and Control of Series/Series-Parallel Compensated Resonant Converter for Contactless Power Transfer

Series/series (S/S) and series/parallel (S/P) compensations are widely used in contactless power transfer systems. However, the inductive input impedance of the S/S compensated converter operating at an output voltage gain intersection point impairs the system’s efficiency, and the output voltage of the S/P compensated converter operating at resonant frequency is quite sensitive to variation of transformer’s parameters caused by air gap change or misalignment. This paper proposes a novel series/series–parallel (S/SP) compensation topology to achieve both high efficiency and good output controllability. The frequency-domain and time-domain analyses of the proposed resonant converter are performed in this paper. Similar to the conventional resonant converters, both phase-locked-loop (PLL) control and fixed-frequency control can be employed. A 60-W prototype with PLL control and a 1.5-kW prototype with fixed-frequency control are built to verify the theoretical analysis. To perform the input-to-output voltage gain comparison, an S/P compensated converter is also fabricated. Experimental results verify the effectiveness of the proposed compensation method. The efficiency of the fabricated S/SP prototype reaches 95.2% at an output power of 1.5 kW with a 10-cm air gap between windings.

High-Efficiency Contactless Power Transfer System for Electric Vehicle Battery Charging Application

In this paper, a contactless charging system for an electric vehicle (EV) battery is proposed. The system consists of three parts: 1) a high-frequency power supply from a full-bridge inverter with frequency modulation; 2) a loosely coupled transformer that utilizes series resonant capacitors for both the primary and secondary windings; and 3) a rectification output circuit that uses a full-bridge diode rectifier. With carefully selected compensation network parameters, zero-voltage switching can be ensured for all the primary switches within the full range of an EV battery charging procedure, which allows the use of low ON-state resistance power MOSFETs to achieve high-frequency operation and system efficiency. The design of loosely coupled transformer is simulated and verified by finite element analysis software. For a 4-kW hardware prototype, the peak dc–dc efficiency reaches 98% and 96.6% under 4- and 8-cm air gap conditions, respectively. The prototype was tested with an electronic load and a home-modified EV to verify the performance of constant current and constant voltage control and their transitions.

Design of an Improved Type Rotary Inductive Coupling Structure for Rotatable Contactless Power Transfer System

This paper is aimed at analyzing the rotary inductive coupling structure of contactless rotary transformer. The main feature of the proposed rotatable contactless power transfer system is which winding is coaxial-interlayered for improving the magnetic coupling capability. There is no ferrite core used in the secondary-side of the rotary inductive coupling structure, this helps to ease the exerted force that is stress by the secondary-side on spindle. In order to verify the feasibility of the proposed contactless power transfer system for rotary applications, an inductive powered rotary machinery and the control system have been integrated. The experimental results show that the maximum power transfer efficiency of the proposed rotary inductive coupling structure is about 94.8%. The maximum output power received in the load end is 1030 W with transmission efficiency of 88%.

A Review of Contactless Electrical Power Transfer: Applications, Challenges and Future Trends

Methods of contactless electrical power transfer technologies have been surveyed and results are presented here. In this among, the inductive based contactless electrical power transfer systems are investigated in more detail. The principles, structures and operations of the systems as well as their methods presented in the literature are reviewed and their applications are explored. Also, current challenges and opportunities and future trends are noted. An effective index is proposed to compare different contactless power transfer systems describing their present statuses and the future trends. Finally, some remarks and recommendations regarding future studies are proposed.

無人搬送装置への非接触給電技術の導入

無人搬送装置への非接触給電技術の導入

Modelling of Traversal of Airgaps Using Resonant Inductive Coupling

A contactless power transfer system at high frequency incorporating strong coupling between primary and secondary coils is very widely in mobile phones to replace the plug and socket charging. The primary and secondary coils coupled using resonant inductive coupling is modelled using compensation capacitors in the primary and secondary coupled circuits. Theoretical analysis of the system is presented and operating power transfer efficiency under varying conditions of source and load is derived. The model presents the variations in the contactless system for all possible variations in the parameters. Simulated results performed using Matlab at 600 kHz are presented.

Multi-Resonant Compensation Analysis of Contactless Electrial Power Transfer System

The loose coupling structure of Contactless Electrical Power Transfer System (CEPTS) is the main cause of transmission inefficiency. Compensation capacitors were calculated and mounted on both sides of primary and secondary coils which forming the following four compensation topologies: primary secondary series (SS compensation), primary series-secondary parallel (SP compensation), primary parallel-secondary series (PS compensation) and primary secondary parallel (PP compensation). Experiment results show that the transmission efficiency differs according to different compensation topologies. SP structure is the most efficient among these four topologies and the transmission efficiency of SP structure is about 40% higher than that of basic structure without compensation.

Modeling and Characteristic Analysis of Current-Fed Contactless Power Transfer System

Modeling and Characteristic Analysis of Current-Fed Contactless Power Transfer System

Conceptual design of contactless power transfer into HTS receiver coil using normal conducting resonance antenna

The contactless power transfer (CPT) technology based on strongly coupled electromagnetic resonators has been recently explored to realize the large power delivery and storage without any cable or wire across a large air gap. As the CPT technology makes possible the process of connector-free charging, it has been studied for practical applications to a variety of power applications. In the superconducting magnet system, a widespread method of electric energy supply is realized by the current lead which is one of indispensable subsystems in the power transfer equipment; however, it causes energy losses. To overcome such a problem, the combination CPT technology with HTS receiver coils has been proposed. It is called as, superconducting contactless power transfer (SUCPT) system. Such a technique has been expected a reasonable approach to provide a safe and convenient way of charging or storage without connecting joints in the superconducting applications. In this study, we presented the feasibility and various effects of transmission property from room temperature to very low temperature vessel within 40cm under different material’s cooling vessels using radio frequency (RF) generator is 370KHz.

Operating Characteristics of Contactless Power Transfer From HTS Antenna to Copper Receiver With Inserted Resonator Through Large Air Gap

With the fast development of various wireless charging applications such as cell phones and electric vehicles, there is substantial interest in contactless power charging across an air gap. The contactless power transfer (CPT) system based on the resonance coupling method, which is composed of separate coils with the same resonance frequency, is feasible for exchanging energy within 2 m. However, generally, because the contactless charging system adopts a normal conducting wire, the size of the antenna is too large to be equipped to deliver a large amount of power promptly. From this point of view, we propose the combination of CPT technology with high-temperature superconducting (HTS) transmitter antenna, which we call the superconducting contactless power transfer (SUCPT). The superconducting transmitter antenna can deliver a mass amount of electric energy in spite of a small-scale antenna. The SUCPT technique is expected as a refined option to transfer a large amount of power and extend the distance. In this study, our research team achieved the improvement of transmission efficiency and extension of transfer distance using an HTS antenna in the inserted resonator coil between the HTS antenna and normal conducting receiver coils. We achieved improved transfer distance and quantity of about 25% compared with the normal conducting antenna under the same power conditions.

A Bidirectional Contactless Power Transfer System Based on Quantum Modulation

Contactless power transfer is an emerging technology. It is widely used in industrial and consumer electronic products. In this paper, a bidirectional contactless power transfer system for wireless vehicle charger is presented based on quantum modulation method. By applying this novel amplitude modulation method, switching losses and electromagnetic noise are greatly reduced and the whole system efficiency increased as well. Firstly, the operational principle of the contactless power transfer system is reviewed. The frequency analysis of the contactless power transfer system based on series resonant converter is deduced in detail. Besides, the voltage gain and phase feature of resonant tank are shown. Then, the quantum method for bidirectional power flow is explained in detail. The controller framework based on a simple analogous circuit is analysed as well. In additional, a simulation of the bidirectional contactless power transfer system based on quantum modulation by computer is presented to demonstrate the effectiveness of this method. Then, the conclusion of contactless power transfer system of bidirectional power flow is given at the end.

Operating characteristics of contactless power transfer for electric vehicle from HTS antenna to normal conducting receiver

As contactless power transfer (CPT) technology using strongly coupled electromagnetic resonators is a recently explored technique to realize the large power delivery and storage without any cable or wire, this technique is required for diffusion of electric vehicles (EVs) since it makes possible a convenient charging system. Typically, since the normal conducting coils are used as a transmitting coil in the CPT system, there is limited to deliver the large power promptly. From this reason, we proposed the combination CPT technology with HTS transmitting antenna, it is called as, superconducting contactless power transfer for EV (SUCPT4EV) system. As the HTS coil has an enough current density and high quality factor Q value, it can deliver a mass amount of electric energy and improved efficiency in spite of a small scale antenna. The SUCPT4EV system has been expected as a reasonable option to improve the transfer efficiency of large electric power. In this study, we examined the improvement of transmission efficiency and properties for HTS transmitted antenna coils within 40cm distance at radio frequency (RF) generator of 60W, 370kHz. In addition, we achieved impedance matching conditions for different material coils between HTS and normal conductors.

Trifoliate Three-Phase Contactless Power Transformer in Case of Winding-Alignment

This paper proposes a trifoliate three-phase contactless power transformer. This transformer can achieve balanced electrical behavior between three phases at winding alignment. For this transformer, models are presented with accompanying detailed explanations. The models reproduce the electrical behavior more precisely than conventional models. A contactless power transfer system using a prototype of the proposed transformer and the resonant capacitances estimated by the models works effectively and attains good performance levels. In addition, in winding misalignments with slight displacements, the system is able to maintain these high-performance levels.

Effects of Coil Misalignments on theMagnetic Field and Magnetic ForceComponents between Circular Filaments

Wireless transfer of electrical energy between air-cored circular coils can be achieved using contactless inductive power transfer (CIPT) system. Notwithstanding, the aim of designing CIPT systems is not always realized because of coil misalignments between the primary and the secondary coils. Based on this information, the author of this paper analyses the effects of lateral and angular misalignments on the magnetic field and the magnetic force between filamentarycircularcoilswhicharearbitrarilypositionedinspace.Thisinvestigation is achieved based on advanced and relevant models formulated in the literature. Detailed results obtained using SCILAB application software is given.

Cooling Structure for Large Capacity H-shaped Core Contactless Power Transformers for Electric Vehicles

Contactless power transfer systems for charging electric vehicles require a high efficiency, a large air gap, and a good tolerance to lateral misalignment and need to be compact and lightweight. Contactless power transformers have two types of structures: a single-sided transformer with a circular core and a double-sided transformer with a rectangular core. Past studies showed that H-shaped rectangular core transformers are more suitable for vehicles than circular core transformers.However, the cooling of cores located between two magnetic poles is a major challenge for double-sided transformers. In particular, this problem is serious for large capacity transformers such as fast chargers because the loss density is higher than for normal charge transformers. If the radiator interrupts the magnetic flux, not only are eddy current losses created but a coupling is also prevented.This paper proposes a novel cooling structure based on H-shaped core transformers. In the novel structure, radiator metal bars are inserted parallel to the main magnetic flux. As a result, the cooling performance is improved without compromising efficiency.

Output Voltage Control of Movable Contactless Power Transfer for Linear Induction Motor

Linear motors have been widely used in industry and transportation applications. Conventionally, linear motors are supplied by the long power cables or sliding contacts. Insufferable defects of these supply methods are friction, sparks, risk of electric shock, inflexible, and high maintenance cost. Movable contactless power transfer (MCPT) system is an alternative proposal for supply of linear motors. MPCT is based on Amperes and Faradays Laws, uses an alternating magnetic field to deliver electrical power across air to load without physical contact [.

Exact Analysis of Frequency Splitting Phenomena of Contactless Power Transfer Systems

Frequency splitting phenomena are investigated systematically by circuit theory in a series-tuned contactless power transfer (CPT) system. First, in a symmetrical CPT system, the splitting equation is defined and the key frequency splitting characteristics are described by the trough and the ridge equations in a complete fashion. The even and the odd splitting frequencies are exactly two roots of the ridge equation; the splitting coupling is determined theoretically when the even and odd splitting frequencies merge together. Second, in an unsymmetrical CPT system, the idea of the trough and the ridge equation is exploited to find exactly the splitting coupling. Next, the relationship between frequency bifurcation and splitting is elucidated; and a zero-phase control method is suggested to track the splitting frequency when the coupling changes in the splitting region. Finally, the theoretical results are validated by a 10-W prototype with planar spiral coils.

Effects and Properties of Contactless Power Transfer for HTS Receivers With Four-Separate Resonance Coils

Contactless power transfer (CPT) technology is an available option to realize the possibility of power delivery and storage with connector-free devices across an air gap. The CPT system based on a strong resonance coupling, which consists of four separate coils with the same resonance frequency, can possibly exchange energy within 2 m. We propose a combination CPT technology with HTS receiver coils, and call it the superconducting contactless power transfer (SUCPT) system. The SUCPT technique is expected to be a noble option for transferring electric power from room temperature to a very low temperature vessel without connectors and can improve the portability of the superconducting system. The SUCPT resonance coils consist of source (copper), Tx (copper), Rx (HTS), and load (HTS) coils. The impedance matching for electromagnetically coupled resonators between Tx and Rx coils is sensitive and plays an important role to improve transfer efficiency and distance. In this study, we examined the transmission efficiency and properties of the SUCPT phenomenon with four separate coils from antenna parts of copper coils at 300 K to receiver parts of HTS wire at 77 K as long as the receiver is within 1.1 m distance. Also, we obtained adequate relations between directionality and transmission efficiency for different positions.