USV charging based on WPT system

With the increasing demand of water and underwater exploration, more and more electric unmanned surface vehicles (USV) are put into use in recent years. However, because of the present battery technology limits, these devices require to be recharged frequently that is a challenging problem taking into account the complex water environment where these equipments are acting. To improve safety and convenience of USV charging a wireless power transfer (WPT) system is proposed in this dissertation. In this case, the boat can be controlled to go to the charging facilities. During charging by the implemented WPT system, the state of charging can be remotely monitored by host computer. The moving control is based on embedded system. The relative position between transmitting coil and receiving coil is supposed to be sensed by magnetic sensor, since the relative position has great impact on transmission efficiency. The remote monitoring software was implemented in the host computer and was developed in LABVIEW. A graphical user interface was developed to control the boat moving and collect the data from the WPT and the boat sensors. The effectiveness of the proposed system was tested for instance in the laboratory environment and in-field tests are also planned in the near future.Com a crescente procura da exploração em ambientes aquáticos e subaquáticos , os veículos elétricos de superfície não tripulados ("electric unmanned surface vehicle" -USV) têm sido cada vez mais utilizados nestes últimos anos. No entanto, devido aos limites atuais relacionados com a tecnologia utilizada nas baterias, os dispositivos precisam de ser recarregados com frequência para poderem operar num ambiente aquático complexo. Para melhorar a segurança e a conveniência do carregamento da bateria de um USV, um sistema para recarregamento da bateria de um barco não tripulado através de transferência de energia sem fios("wireless power transfer" - WPT) é proposto nesta dissertação. Neste caso de estudo, o barco tem a capacidade de ser controlado para chegar a um ponto de recarregamento da bateria, que se encontra fixado por uma doca mecânica. Enquanto o sistema WPT érecarregado, os dados associados ao processo de recarregamento da bateria podem ser monitorizados por um computador host. O controlo da movimentação do barco é baseado num sistema embebido. A posição relativa entre a bobina transmissora e a bobina receptora deve ser detectada pelo sensor magnético, uma vez que a posição relativa tem um grande impacto na eficiência da transmissão. Em termos do computador host, foi utilizado o software LABVIEW para programar a interface que permite controlar o movimento do barco e recolher os dados. Finalmente, a eficácia do sistema proposto foi experimentada e testada num ambiente de laboratório

Design of High Efficiency Wireless Power Thansfer System With Nonlinear Resonator

Wireless power transfer technology (WPT) has been rapidly developed in recent years. The primary benefit of WPT is that it replaces the traditional wire charging with a cordless charging method. WPT technology has been applied in many fields, such as bio-implants, electric vehicles, and wirelessly charging systems. According to the different energy transmission mechanism, WPT technology can be divided into magnetic field coupling (includes magnetically coupled inductive and magnetically-coupled resonant), microwave radiation, laser emission, electrical-field coupling, and ultrasonic transmission type. Among these technologies, the magnetic resonance coupling method has a better promise because of its long transfer distance and high efficiency. However, there are some questions that need to be resolved, among which the most prominent is that the technology has a low tolerance to the variations of the coupling factor because of the frequency splitting phenomenon, which would lead to transmission efficiency degradation of magnetic resonance coupling WPT systems. Hence, based on reviewing the research status and trend of WPT technology, this paper analyses the frequency splitting phenomenon of the wireless power transfer system, discusses the duffing resonator circuit and its properties, and designs a kind of high-efficiency wireless power transfer inductive system with both non-linear inductors and non-linear capacitors. The main research works of this paper are as follows: Firstly, aiming at the frequency splitting problem during magnetic coupled resonance wireless power transmission, the frequency splitting phenomenon for the wireless power transfer system is studied by an electric circuit model method. The expression of the relationship between the load voltage, transmission efficiency, and coupling factor was derived, and the law of frequency splitting is discussed. Furtherly, an analysis of frequency splitting based on simulation also presented. Finally, the frequency splitting suppression method is proposed. The above research work provides a theoretical basis for solving the problem of frequency splitting and designing a kind of high-efficiency WPT system. Subsequently, a duffing resonator circuit with a nonlinear capacitor, which can eliminate the frequency splitting and keep the high transmission efficiency and power delivered to the load is developed. With the help MATLAB software, the properties of the duffing resonance circuit are discussed furtherly. The results show that the duffing resonance circuit has significantly wider bandwidth than the conventional linear resonance circuit while achieving a similar amplitude level. Finally, the high efficiency non-linear wireless power transfer system based on non-linear inductors with ferromagnetic thin film core and non-linear capacitors with ferroelectric thin film dielectrics is designed. Moreover, the system\u27s performance is improved, the range of coupling factors significantly extended while both load power and high PTE were maintained. The reason for the high efficiency of the system is furtherly discussed, and the research result shows that non-linear inductor with ferromagnetic thin film core has variable inductance which can be synchronously changed along with the current through the inductor in the circuit. The non-linear capacitor with ferroelectric thin film dielectrics can also have variable capacitance, which can be synchronously changed along with the voltage applied to the capacitor. However, the voltage across the capacitor and current through the inductors are different initially, high power transmission efficiency can be achieved by self-tuning capability of inductance and capacitance from the film based non-linear resonators. Research results of this paper can lay the solid foundations for the application of WPT technology in the fields of bio-implants, electric vehicles, wirelessly charging systems, etc

Investigation of wireless power transfer-based eddy current non-destructive testing and evaluation

PhD ThesisEddy current testing (ECT) is a non-contact inspection widely used as non-destructive testing and evaluation (NDT&E) of pipeline and rail lines due to its high sensitivity to surface and subsurface defects, cheap operating cost, tolerance to harsh environments, and capability of a customisable probe for complex geometric surfaces. However, the remote field of transmitter-receiver (Tx-Rx) ECT depends on the Tx-Rx coils gap, orientation, and lift-off distance, despite each coil responding to the effect of sample parameters according to its liftoff distance. They bring challenges to accurate defect detection and characterisation by weakening the ECT probe’s transfer response, affecting sensitivity to the defect, distorting the amplitude of the extracted features, and responding with fewer feature points at non-efficient energy transfer. Therefore, this study proposed a magnetically-coupled resonant wireless power transfer (WPT)-based ECT (WPTECT) concept to build the relationship between Tx-Rx coil at maximum energy transfer response, including shifting and splitting (resonance) frequency behaviour. The proposed WPTECT system was investigated in three different studies viz., (1) investigated the multiple resonance point features for detection and characterisation of slots on two different aluminium samples using a series-series (SS) topology of WPTECT; (2) mapped and scanned pipeline with a natural dent defect using a flexible printed coil (FPC) array probe based on the parallel-parallel (PP) topology of WPTECT; and (3) evaluated five different WPTECT topologies for optimal response and extracted features and characterised entire parameters of inclined angular Rolling Contact Fatigue (RCF) cracks in a rail-line material via an optimised topology. Multiple feature extraction, selection, and fusion were evaluated for the defect profile and compared in the study, unattainable by other ECT methods. The first study's contribution investigated multiple resonances and principal component analysis (PCA) features of the transfer response from scanning (eight) slots on two aluminium samples. The results have shown the potential of the multiple features for slot depth and width characterisation and demonstrated that the eddy-current density is highest at two points proportionate to the slot width. The second study's contribution provided a larger area scanning capability in a single probe amenable to complex geometrical structures like curvature surfaces. Among the extracted individual and fused features for defect reconstruction, the multi-layer feed-forward Deep learning-based multiple feature fusion has better 3D defect reconstruction, whilst the second resonances feature provided better local information than the first one for investigating pipeline dent area. The third study's contribution optimised WPTECT topology for multiple feature points capability and its optimal features extraction at the desired lift-off conditions. The PP and combined PP and SS (PS-PS) WPTECT topologies responded with multiple resonances compared to the other three topologies, with single resonance, under the same experimental situation. However, the extracted features from PS-PS topology provided the lowest sensitivity to lift-off distances and reconstructed depth, width, and inclined angle of RCF cracks with a maximum correlation, R2 -value of 96.4%, 93.1%, and 79.1%, respectively, and root-mean-square-error of 0.05mm, 0.08mm, and 6.60 , respectively. The demonstrated magnetically-coupled resonant WPTECT Tx-Rx probe characterised defects in oil and gas pipelines and rail lines through multiple features for multiple parameters information. Further work can investigate the phase of the transfer response as expected to offer robust features for material characterisation. The WPTECT system can be miniaturised using WPT IC chips as portable systems to characterise multiple layers parameters. It can further evaluate the thickness and gap between two concentric conductive tubes; pressure tube encircled by calandria tube in nuclear reactor fuel channels.PTDF Nigeri