The Experts below are selected from a list of 111 Experts worldwide ranked by ideXlab platform
Xiaofang Yu - One of the best experts on this subject based on the ideXlab platform.
-
robust wireless power transfer using a nonlinear parity time symmetric circuit
Nature, 2017Co-Authors: Sid Assawaworrarit, Xiaofang YuAbstract:A nonlinear parity–time-symmetric circuit is used to enable robust wireless power transfer to a Moving Device over a distance of one metre without the need for tuning. A robust, efficient technology for wirelessly charging Devices would be a substantial boost for a range of mobile applications including implantable medical Devices and electric vehicles. Shanhui Fan and colleagues propose and test a new way of transferring power that doesn't require continual tuning as the distance between source and Device is varied, contrary to other approaches. They use the principle of parity–time symmetry, a concept that has been intensively explored in recent years in optical applications by carefully balancing gain and loss, and which has led to new and unusual regimes. Here they apply the principle to electric circuitry, and show how electromagnetic power can be transferred between two metallic plates with an efficiency that is maintained over distances of up to a metre. The work demonstrates a wirelessly powered light-emitting diode (LED) that shines with constant brightness even when its position relative to the power source changes. Considerable progress in wireless power transfer has been made in the realm of non-radiative transfer, which employs magnetic-field coupling in the near field1,2,3,4. A combination of circuit resonance and impedance transformation is often used to help to achieve efficient transfer of power over a predetermined distance of about the size of the resonators3,4. The development of non-radiative wireless power transfer has paved the way towards real-world applications such as wireless powering of implantable medical Devices and wireless charging of stationary electric vehicles1,2,5,6,7,8. However, it remains a fundamental challenge to create a wireless power transfer system in which the transfer efficiency is robust against the variation of operating conditions. Here we propose theoretically and demonstrate experimentally that a parity–time-symmetric circuit incorporating a nonlinear gain saturation element provides robust wireless power transfer. Our results show that the transfer efficiency remains near unity over a distance variation of approximately one metre, without the need for any tuning. This is in contrast with conventional methods where high transfer efficiency can only be maintained by constantly tuning the frequency or the internal coupling parameters as the transfer distance or the relative orientation of the source and receiver units is varied. The use of a nonlinear parity–time-symmetric circuit should enable robust wireless power transfer to Moving Devices or vehicles9,10.
Sid Assawaworrarit - One of the best experts on this subject based on the ideXlab platform.
-
robust and efficient wireless power transfer using a switch mode implementation of a nonlinear parity time symmetric circuit
Nature Electronics, 2020Co-Authors: Sid AssawaworraritAbstract:Stationary wireless power transfer has been deployed commercially and can be used to charge a variety of Devices, including mobile phones and parked electric vehicles. However, wireless power transfer set-ups typically suffer from an inherent sensitivity to the relative movement of the Device with respect to the power source. Nonlinear parity–time symmetric circuits could be used to deliver robust wireless power transfer even while a Device is Moving rapidly, but previous implementations have relied on an inefficient gain element based on an operation-amplifier circuit, which has inherent loss, and hence have exhibited poor total system efficiency. Here we show that robust and efficient wireless power transfer can be achieved by using a power-efficient switch-mode amplifier with current-sensing feedback in a parity–time symmetric circuit. In this circuit, the parity–time symmetry guarantees that the effective load impedance on the switch-mode amplifier remains constant, and hence the amplifier maintains high efficiency despite variation of the transfer distance. We experimentally demonstrate a nonlinear parity–time symmetric radiofrequency circuit that can wirelessly transfer around 10 W of power to a Moving Device with a nearly constant total efficiency of 92% and over a distance from 0 to 65 cm. A parity–time symmetric circuit that uses a switch-mode amplifier and current-sensing phase-delay feedback can wirelessly transfer around 10 W of power to a Moving Device with a nearly constant total efficiency of 92%.
-
robust wireless power transfer using a nonlinear parity time symmetric circuit
Nature, 2017Co-Authors: Sid Assawaworrarit, Xiaofang YuAbstract:A nonlinear parity–time-symmetric circuit is used to enable robust wireless power transfer to a Moving Device over a distance of one metre without the need for tuning. A robust, efficient technology for wirelessly charging Devices would be a substantial boost for a range of mobile applications including implantable medical Devices and electric vehicles. Shanhui Fan and colleagues propose and test a new way of transferring power that doesn't require continual tuning as the distance between source and Device is varied, contrary to other approaches. They use the principle of parity–time symmetry, a concept that has been intensively explored in recent years in optical applications by carefully balancing gain and loss, and which has led to new and unusual regimes. Here they apply the principle to electric circuitry, and show how electromagnetic power can be transferred between two metallic plates with an efficiency that is maintained over distances of up to a metre. The work demonstrates a wirelessly powered light-emitting diode (LED) that shines with constant brightness even when its position relative to the power source changes. Considerable progress in wireless power transfer has been made in the realm of non-radiative transfer, which employs magnetic-field coupling in the near field1,2,3,4. A combination of circuit resonance and impedance transformation is often used to help to achieve efficient transfer of power over a predetermined distance of about the size of the resonators3,4. The development of non-radiative wireless power transfer has paved the way towards real-world applications such as wireless powering of implantable medical Devices and wireless charging of stationary electric vehicles1,2,5,6,7,8. However, it remains a fundamental challenge to create a wireless power transfer system in which the transfer efficiency is robust against the variation of operating conditions. Here we propose theoretically and demonstrate experimentally that a parity–time-symmetric circuit incorporating a nonlinear gain saturation element provides robust wireless power transfer. Our results show that the transfer efficiency remains near unity over a distance variation of approximately one metre, without the need for any tuning. This is in contrast with conventional methods where high transfer efficiency can only be maintained by constantly tuning the frequency or the internal coupling parameters as the transfer distance or the relative orientation of the source and receiver units is varied. The use of a nonlinear parity–time-symmetric circuit should enable robust wireless power transfer to Moving Devices or vehicles9,10.
D E Macpherson - One of the best experts on this subject based on the ideXlab platform.
-
an airborne radar power supply with contactless transfer of energy part i rotating transformer
IEEE Transactions on Industrial Electronics, 2007Co-Authors: Konstantinos Papastergiou, D E MacphersonAbstract:Reliability and precision are key requirements for electronic systems in aerospace applications. Transferring electrical energy from a stationary to a Moving Device involves wearable parts such as slip rings and brushes. This paper examines the possibility of using a rotating transformer for contactless transfer of energy from the base to the revolving platform of an airborne radar system. The first part of the series focuses on the magnetic interface, investigating its electrical properties and their association with the core and windings geometry. The reader will gain an understanding of the merits and limitations of this technology and will be able to assess its suitability for other applications. The effects of the increased leakage and reduced magnetizing inductances of the transformer are investigated, and two winding layouts are proposed and characterized by measurements and finite-element analysis. Some equations are presented along with practical guidelines on designing a rotating transformer with a 0.25-2-mm air gap. The transformer voltage gain and efficiency plots are introduced as performance-assessment tools. The impact of the air-gap stray flux on the winding conduction losses is shown, and some electromagnetic-compatibility considerations are presented. Finally, a mechanical layout for a 1-kW rotating transformer is proposed.
Zhang Jun - One of the best experts on this subject based on the ideXlab platform.
-
guide rail assembly guide rail and robot Moving Device
2015Co-Authors: Liu Hua, Tao Zhipeng, Zheng Dexin, Ruan Zihong, Dai Lin, Wu Yue-liang, Ye Han, Jiang Tao, Zhang JunAbstract:The invention relates to a guide rail assembly, a guide rail and a robot Moving Device. By means of the guide rail assembly, the guide rail and the robot Moving Device, the technical problem that an existing guide rail assembly is liable to deformation in use is solved. The guide rail assembly comprises a base and a support plate arranged at the upper end of the base. A linear guide rail belt is further fixed to the support plate. The linear guide rail belt is arranged in the length direction of the base, and the middles of the left side wall and the right side wall of the linear guide rail belt are each provided with an inward-concave groove zone. The guide rail assembly further comprises a sliding part arranged in an upside down mode. The end face of the sliding part is of a [-shaped structure. The inner walls of the two sides of the sliding part are provided with protrusions respectively, and the protrusions are matched with grooves in the groove zones. The sliding part is placed on the linear guide rail belt in an upside down mode, and the two protrusions on the sliding part are clamped in the groove zones on the two sides of the linear guide rail belt respectively. The guide rail is composed of two guide rail assemblies. The robot Moving Device comprises a robot and the guide rail. A base under the robot is fixed to two sliding parts on two guide rail assemblies.
Guohua Xu - One of the best experts on this subject based on the ideXlab platform.
-
tin soldering system of automatic tin soldering robot
2011Co-Authors: Jijiang Min, Zhangfeng Li, Qinghai Xu, Dongsheng Qu, Yan Sun, Guohua XuAbstract:The invention discloses a tin soldering system of an automatic tin soldering robot, which comprises a soldering bit, a soldering bit Moving mechanism and a tin wire accurate positioning mechanism, wherein the soldering bit Moving mechanism comprises a Moving Device connected with the soldering bit; the Moving Device comprises a connecting block, an air cylinder, a sliding plate and a linear sliding rail; the upper end of the soldering bit and the cylinder body of the air cylinder are connected together by the connecting block, and the connecting block is also connected with the sliding plate; the sliding plate is in sliding connection with the linear sliding rail; a tin wire guide nozzle of the tin wire accurate positioning mechanism is connected with the connecting block through a connecting rod, the connecting block is connected with a connecting shaft, a deflection block is fixedly connected with the connecting shaft, the connecting shaft is connected with a pitching block in a rotating mode, the pitching block is connected with a clamping block, the clamping block is fixed on the upper end of the soldering bit, a horizontal adjustment screw is connected with the deflection block in a rotating mode, and the front end of the horizontal adjustment screw is connected with the pitching block in a sliding mode. The invention can reduce the abrasion of a mechanism which drives the soldering bit to move up and down, ensures the precision of the repeating motion of the soldering bit in tin soldering, and can enable transported tin wires accurately to be positioned to a tin soldering point of the soldering bit.