Inductive Power Transfer Technology Research Articles

Coupled EMAG-CFD-Thermal analysis of a novel SST system utilizing forced-liquid cooling with biodegradable dielectric fluid

Solid state transformers (SSTs) are at the forefront of emerging technologies, enhancing distribution and transmission networks. These transformers facilitate the development of highly controllable and robust smart grids, seamlessly integrating renewable energy sources and accommodating connections for both alternating current and direct current components/lines at medium or low voltage levels. This research paper introduces an innovative SST incorporating the inductive power transfer (IPT) technology, currently under development within SSTAR, a Horizon Europe project. This novel device operates at a frequency of 50 kHz and provides with an output power of 50 kW. The IPT system is submerged in an ester-based, biodegradable dielectric fluid, providing effective cooling and insulation characteristics. The primary focus of this research is to highlight the guidelines for the optimal design of the forced liquid cooling system of the SST module. The analysis employs a multi-faceted simulation strategy to calculate the cooling aspects of the transformer, utilizing the commercial software ANSYS. This involves 3D coupled Electromagnetic (EMAG) - Computational Fluid Dynamics (CFD) simulations, as well as stand-alone CFD and thermal FEA simulations, ensuring robust cross-verification of the obtained results. This novel SST exhibits improved thermal performance, achieving a hot-spot temperature of 58 °C, the lowest value found in similar research studies. The findings underscore the efficiency and robustness of the proposed design, marking a significant step towards the realization of active and environmentally-friendly electrical networks.

Sizing Methodology of Dynamic Wireless Charging Infrastructures for Electric Vehicles in Highways: An Italian Case Study

The necessity of pushing the road mobility towards more sustainable solutions has become of undeniable importance in last years. For this reason, both research and industry are constantly investigating new technologies able to make the usage of battery electric vehicles(BEV) as accessible and usable as traditional internal combustion engine vehicles (ICEV). One of the most limiting issues concerns the short range of electric vehicles, which complicates their use for long distances, such as for highway travels. A promising solution seems to be the “charge-while-driving” approach, by exploiting the inductive dynamic wireless power transfer (DWPT) technology. Nevertheless, such systems show different issues, first of all, high investment and maintenance costs. Furthermore, it is not clear how extensive a potential dynamic wireless charging infrastructure needs to be to make a real advantage for electric vehicle drivers. As a consequence, the aim of this paper is to introduce a new methodology to estimate the number and length of wireless charging sections necessary to allow the maximum number of electric vehicles to travel a specific highway without the need to stop for a recharge at a service area. Specifically, the methodology is based on a algorithm that, starting by real traffic data, simulates vehicle flows and defines the basic layout of the wireless charging infrastructure. This simulator can provide a decision support tool for highway road operators.

Design of Inductive Power Transfer Charging System with Weak Coupling Coefficient

Inductive power transfer (IPT) technology is used in various applications owing to its safety features, robust environmental adaptability, and convenience. In some special applications, the charging pads are required to be as compact as possible to accommodate practical spatial requirements, and even size requirements dictate that the diameter of the charging pad matches the air gap. However, such requirements bring about a decrease in the transmission efficiency, power, and tolerance to misalignment of the system. In this paper, by comparing a double-sided inductor–capacitor–capacitor (LCC), double-sided inductor–capacitor–inductor (LCL), series–series (SS), and inductor–capacitor–capacitor–series (LCC-S) compensation topologies in IPT systems, we identified a double-sided LCC compensation topology that is suitable for weak coupling coefficients. Furthermore, this study modeled and simulated the typical parameters of coreless coils in circular power pads, such as the number of coil layers, turns, wire diameter, and wire spacing, to enhance the mutual inductance of the magnetic coupler during misalignment and long-distance transmission. A wireless charging system with 640 W output power was built, and the experimental results show that a maximum dc-dc efficiency of over 86% is achieved across a 200 mm air gap when the circular power pad with a diameter of 200 mm is well aligned. The experimental results show that using a suitable compensation topology and optimizing the charging pad parameters enables efficient IPT system operation when the coupling coefficient is 0.02.

WIRELESS CHARGING FOR ELECTRICAL VEHICLES

Nowadays Wireless power transmission (WPT) is popular and gaining technology finding its application in various fields. The power is transferred from a source to an electrical load without the need of interconnections. Wireless power Transmission (WPT) is useful to power electrical devices where physical wiring is not possible or inconvenient. The technology uses the principle of mutual inductance. One of the best future applications finds in automotive sector especially in Electrical Vehicles. This project deals with research and development of wireless charging systems for Electric Vehicles using Wireless transmission. The main goal is to transmit power using resonance coupling and to build charging systems. The System deals with AC source, transmission coil, reception coil, converter and electric load which are battery. As Electric Vehicles (EVs) continue to gain popularity as a sustainable transportation solution, the need for efficient charging infrastructure becomes increasingly critical. Wireless charging technology presents a promising solution to address the limitations of traditional plug-in charging systems, offering convenience and flexibility to EV users. This Project explores the concept of wireless EV charging while the vehicle is in motion, also known as dynamic wirelesscharging (DWC). By integrating inductive power transfer (IPT) technology with dynamic charging infrastructure embedded in roadways or dedicated lanes, vehicles can replenish their batteries continuously while in motion, extending their range and reducing the need for frequent stops. Furthermore, DWC has the potential to enhance the feasibility and adoption of EVs in various sectors, including public transportation, logistics, and personal mobility. This abstract provides a comprehensive overview of the emerging field of wireless EV charging while the vehicle is inmotion, highlighting its benefits, challenges, and future prospects.

Wireless Power Transfer for Unmanned Underwater Vehicles: Technologies, Challenges and Applications

Unmanned underwater vehicles (UUVs) are key technologies to conduct preventive inspection and maintenance tasks in offshore renewable energy plants. Making such vehicles autonomous would lead to benefits such as improved availability, cost reduction and carbon emission minimization. However, some technological aspects, including the powering of these devices, remain with a long way to go. In this context, underwater wireless power transfer (UWPT) solutions have potential to overcome UUV powering drawbacks. Considering the relevance of this topic for offshore renewable plants, this work aims to provide a comprehensive summary of the state of the art regarding UPWT technologies. A technology intelligence study is conducted by means of a bibliographical survey. Regarding underwater wireless power transfer, the main methods are reviewed, and it is concluded that inductive wireless power transfer (IWPT) technologies have the most potential. These inductive systems are described, and their challenges in underwater environments are presented. A review of the underwater IWPT experiments and applications is conducted, and innovative solutions are listed. Achieving efficient and reliable UWPT technologies is not trivial, but significant progress is identified. Generally, the latest solutions exhibit efficiencies between 88% and 93% in laboratory settings, with power ratings reaching up to 1–3 kW. Based on the assessment, a power transfer within the range of 1 kW appears to be feasible and may be sufficient to operate small UUVs. However, work-class UUVs require at least a tenfold power increase. Thus, although UPWT has advanced significantly, further research is required to industrially establish these technologies.

Design and Analysis of an H-Type Pickup for Multi-Segment Wireless Power Transfer Systems

To tackle the complex wireless power supply requirements in the Automated Material Handling System (AMHS) of semiconductor wafer factories, this paper presents a design method for a magnetic coupling mechanism based on a Multi-Segment Wireless Power Transfer (MSWPT) system for dynamic wireless power supply in segmented track configurations. Firstly, the track is approached using Inductive Power Transfer (IPT) technology combined with an LCC-S resonant structure transmitter (Tx). Following this, the feasibility of the H-type pickup is assessed through magnetic and electrical circuit analyses, which leads to the preliminary determination of the pickup dimensions by means of finite element magnetic and thermal simulations. Furthermore, an analysis of the mutual inductance drop is conducted under various track structure parameters during track crossing and curve negotiation operation conditions. Secondly, a dual-coil winding method is proposed to reduce the insulation stress on the PCB board. Additionally, a method for calculating the wire length and a design process for the overall parameters of the pickup are derived. Finally, two Txs and a 1.5 kW power receiver (Rx) were designed to verify the mutual inductance fall under the aforementioned conditions. During low-speed full-load operations, a constant-voltage output was achieved through the proposed dual-loop PI control strategy, thereby meeting the requirements for a constant-voltage output in industrial applications.

Design of Compensation Topology for IPT System Considering Coils’ Parameters and Load Variations for CC or CV Output

The inductive power transfer (IPT) technology is drawing increasing attention. Variations in the height of the secondary coil are inevitable due to the fluctuations in the height of the electrical equipment or the pressure of the tires, which leads to variations in the coils’ parameters (self-inductances and mutual inductance). The coils’ parameters and load variations can dramatically affect the performance of the IPT system. In this paper, a unified mathematical model which can describe multiple compensation topologies is established. A design method is proposed to obtain suitable topology and component parameters based on the unified mathematical model and the non-dominated sorting genetic algorithm II. In addition, not only the stable output voltage/current is achieved, but the efficiency and cost are also improved. Finally, two experimental prototypes were built to verify the effectiveness, which has the output characteristics of constant current (3.5A/600W) and constant voltage (72V/100W), respectively. The results show that the output fluctuations are less than 5.63%, and the maximum efficiency is above 94.69% when the coils’ parameters (the primary self-inductance change from 85.76μH to 102.2μH, the secondary self-inductance change from 86.26μH to 102.35μH, and the mutual inductance change from 38.2μH to 72.1μH) and load (double change) vary.

Optimizing Energy Transfer: A Novel Wireless Bypass Charging System for E-Vehicles with Darrieus Technology

This paper presents a parallel resonant inverter-based solution to power several distributed transmitter coils after giving a summary of the available electric vehicle (EV) charging technologies. Where the receiver coil is attached to the car determines which coils are energized in sequence. By means of this approach, Inductive Power Transfer (IPT) Technology functions. Ingenious magnetic induction bypass charging does away with the need for actual connections between the charger and the charging device. Convenient and easy charging of the smartphone is made possible by the charging station's use of magnetic induction. This method uses electromagnetic fields to help the energy transfer between coils placed in the receiving device and the charging station. Close to the charging station, the device's coils oscillate at the same frequency. An electrical current is therefore generated and sent through the receiver coil, so replenishing the device's battery. Offering consumers an easy and practical way to charge their gadgets without the need for cables or plugs is the aim of wireless bypass charging. By enhancing device portability, convenience, and efficiency in the powering process, this invention has the potential to completely transform a number of industries, including consumer electronics, healthcare, and automotive.

A Novel Coupler of Capacitive Power Transfer for Enhancing Underwater Power Transfer Characteristics

Compared to inductive power transfer (IPT) technology, capacitive power transfer (CPT) technology offers unique advantages such as being cost-effective, lightweight, and free from eddy-current losses, making it more suitable for underwater power transfer. Unlike air, water can conduct electricity and the electric conductivity of different kinds of waters varies with different ion concentrations, which would greatly affect the equivalent model of the underwater couplers. To address this issue, multiple types of underwater coupler working in different kinds of water are compared and analyzed. The influence of the electrical conductivity of water on the capacitive coupler is comprehensively analyzed, and the novel capacitive coupler and its equivalent model are proposed to improve power transfer efficiency. To verify the theoretical analysis, the double-sided LC-compensated CPT circuit is built and tap water is used in the experiment. The experimental results are consistent with the theoretical analysis. In addition, the experimental results also validate the superiority of the proposed capacitive coupler compared to existing research.

A Detuned S-S Compensated IPT System With Two Discrete Frequencies for Maintaining Stable Power Transfer Versus Wide Coupling Variation

Stable power transmission is one of the key factors in the inductive power transfer (IPT) system. However, misalignment between the primary and secondary sides is almost inevitable in practice, affecting the system performance due to the coupling variation. With the widespread use of IPT technology, it is desired to transfer power from the primary side to the secondary side with a wide misalignment range as large as possible. To address this issue, the design method of the detuned circuit is widely applied in the IPT system. This paper analyzes the characteristics of the transfer power of the detuned series–series (S-S) topology with frequency variations and proposes a maintaining stable power transfer method versus wide coupling variation by adopting two discrete frequencies. Further, a design step is given to obtain the system parameters. Theoretical and experimental results are provided to demonstrate the misalignment performance of the proposed method. The results show that the coupling range is extended from [0.115-0.2] to [0.115-0.27] with the 5.6% fluctuation of the output power, and the corresponding efficiency varies from 91.46% to 95.52%.

A Review of Capacitive Power Transfer Technology for Electric Vehicle Applications

Electric Vehicle (EV) wireless power transfer technology is an excellent solution to propel EVs forward. The existing wireless power transfer technology for EVs based on Inductive Power Transfer (IPT) technology has the drawbacks of large size, high weight, and high eddy current loss, limiting the further application of this technology. Capacitive Power Transfer (CPT) technology, with its advantages of low cost and light weight, has attracted widespread focus in recent years and has great potential in the field of EV wireless power transfer. This paper begins with the principle of CPT, introduces the potential and development history of CPT technology in the field of EV wireless power transfer, and then reviews the coupling mechanism and resonance compensation network of the CPT system to satisfy the requirements of EV wireless power transfer, including the coupling mechanism of EV static power transfer and dynamic power transfer, and the high-performance resonance compensation network to the requirements of EV wireless power transfer. Finally, this paper reviews the existing problems of CPT technology in the field of EV wireless power transfer and summarizes its future development directions.

A Review of Power Transfer Systems for Light Rail Vehicles: The Case for Capacitive Wireless Power Transfer

Light rail vehicles (LRVs) are increasingly in demand to sustainably meet the transport needs of growing populations in urban centres. LRVs have commonly been powered from the grid by direct-contact overhead catenary systems (OCS); however, catenary-free direct-contact systems, such as via a “hidden rail”, are popular for new installations. Wireless power transfer (WPT) is an emerging power transfer (PT) technology for e-transport with several advantages over direct contact systems, including improved aesthetics and reduced maintenance requirements; however, they are yet to be utilised in LRV systems. This paper provides a review of existing direct-contact and wireless PT technologies for LRVs, followed by an in-depth critical assessment of inductive power transfer (IPT) and capacitive power transfer (CPT) technologies for LRVs. In particular, the feasibility and advantages of CPT for powering LRVs are presented, highlighting the efficacy of CPT with respect to power transfer capability, safety, and other factors. Finally, limitations and recommendations for future works are identified.

Modular Coupler With Integrated Planar Transformer for Wireless EV Charging

A dynamic inductive power transfer (IPT) system is a safe and convenient solution for providing power to electric vehicles (EVs) while they are driving along a roadway. This technology can help reduce the size and cost of the bulky EV batteries without limiting the EV's travelling range. In recent years, practical aspects of dynamic IPT systems have been investigated to advance various IPT technologies from laboratories into roadways. This paper suggest an IPT roadway layout, focusing on a modular IPT system configuration with an integrated semi-loosely coupled planar transformer inside the in-road coupler to mitigate the installation and maintenance concerns of IPT roadways. The proposed configuration keeps the current in the couplers constant and load-independent while providing galvanic isolation between the coupler and the converter, and can be used as a replacement for the conventional LCL and transformer configuration. In order to reduce the number of components used in each module, each in-road coupler is connected to a common H-bridge through a single DC switch to enable individual couplers to be energized independently. Mathematical analysis and simulation results are provided, and validated using a scaled 7.7 kW prototype IPT system employing the proposed configuration.

Design of a Highly Compatible Underwater Wireless Power Transfer Station for Seafloor Observation Equipment

Conventional cabled seafloor observatories (CSOs) power in-situ instruments via wet-mated or dry-mated direct electrical contact (DEC) connectors to achieve long-term and real-time observation. However, the DEC connectors have high risks of water leakage and short circuits in power feeding, especially under high water pressure. This paper proposes a highly compatible underwater station based on inductive wireless power transfer (IPT) technology to address the above reliability issue. A novel energy transmitter with runway-structure coils is applied to the proposed underwater station to cover a sufficient power feeding area so that various in-situ equipment can be powered with desirable misalignment tolerance. The magnetic field distribution is analyzed by both derivation and finite element analysis (FEA) methods, and the principal parameters of the transmitter are further optimized and compared with both the mixed-integer sequential quadratic programming (MISQP) algorithm and the evolutionary algorithm (EA) for better performance. The same results show a reliable optimization process. The WPT circuit characteristics are also investigated to power different loads and improve the power transmission efficiency. The output power decreases, and the transmission efficiency rises and then decreases as the load increases. In addition, receivers with higher mutual inductance have better transmission performance. A prototype of the underwater station has been tested both in air and in water, and the experimental results have proven it can power multiple seafloor observation instruments stably and achieve compatibility requirements. The maximum output power of the station prototype for testing is 100 W, and the maximum overall transmission efficiency is 61%.

Wireless Power Transfer: Principles and Applications [Book News

The book gives a comprehensive view of wireless power transfer (WPT) technologies, with a special emphasis on the multiple-pickup WPT. A number of applications is also described, including the systems employed in portable consumer electronics, in‐flight charging for unmanned aerial vehicles, underwater wireless charging, and the high‐power electrical vehicle (EV) wireless charging that has been already mentioned above. The book is organized in four parts, each one of them consisting of multiple chapters. The first part is divided into two chapters: an overview of several WPT technologies is given, but the main emphasis is given to inductive power transfer (IPT) technology. The second part of the book gives a view of the issues related to the design and optimization of coupled coils and power circuits.

Comprehensive investigation on misalignment tolerance of inductive power transfer systems

Inductive power transfer (IPT) technology is gaining popularity for wireless charging applications of future electric charging for its contactless power supply. The square and circular planar spiral coils are most widely used in wireless power charge due to its simple structure. This paper gives analyses of comparing these two geometry windings in detail. As for an inductive power transfer system, coupling structures, such as line spacing and magnetic core structure, are of paramount importance, because of their significant impact on power transfer efficiency and voltage stability. By analyzing the characteristics of magnetic field distribution of the coupler, influences of coil shape, size, line spacing and core structures on coupling coefficient and coupling coefficient retaining ratio (CCRR) are firstly investigated. Misalignment tolerance under different coupler structures is then conducted, comprehensive optimization schemes of misalignment tolerance improvement are proposed. Results show that for the coupling coefficient and coupling coefficient retaining ratio, the optimal line spacing and core structures are highly dependent on the coil shape, size and air gap. A 3-kW IPT system was also built and experimental validations on original and optimized structures are performed. And the better misalignment tolerance was achieved with the optimal line spacing, transmitting coil and ferrite core structure.

Single‐immittance‐network‐based inductive‐power‐transfer systems for driving multistring lighting‐emmiting diodes with current balance

Multistring arrays of LED in parallel connection are widely applied in lighting fields. Active control and passive methods are utilized to guarantee equal current sharing between different strings with a common voltage source. Compared with active control, the passive methods that adopt purely passive components without real power dissipation are good candidates. Currently, an inductive power transfer (IPT) converter providing a constant voltage (CV) line, followed by some immittance networks that convert the CV line to constant current (CC) outputs, is commonly used to drive multiple LED strings. However, in such a two-conversion-stage scheme, the component count is as many as 3 × N $$ 3\times N $$ , where N $$ N $$ is the number of LED strings, which deviates from compact, low-cost, and simple design ideas. To address it, this paper aims to develop a single-immittance-network-based IPT system to drive multistring LEDs with the current balance. The proposed IPT system can directly provide a CV to CC conversion to drive multistring LEDs with the benefits of simplifying the circuit design, size, and cost. The proposed IPT system also features programmable luminous power, zero-phase-angle (ZPA) input, IPT technology, and load-independent-current (LIC) output. Detailed analysis, implementation, and experiment are presented in this paper.

A Load-Independent Fission-Type Inductive Power Transfer System for 3D Reconfigurable IoT Array

In recent years, the number of electronic devices and appliances that support wireless charging has rapidly increased, owing to the research and development breakthroughs in inductive power transfer (IPT) technology. The existing wireless charging protocols, such as Qi and AirFuel, support only a few devices to be charged simultaneously. They cannot be directly utilized to construct a complex IPT network. This article introduces a reconfigurable three-dimensional (3D) IPT system based on series-parallel (SP) compensation for wirelessly powering multiple adjacent cubic Internet of Things (IoT) devices. These cubes can be configured into different 3D array combinations according to the application demands. After the 3D cube array is formed, a self-detection mechanism runs to turn off the uncoupled coils, such that to maximize the power transmission efficiency of the entire system. These cubes serve as not only IoT loads but also wireless power relays. In this way, the number of loads is not limited by the size of a single transmission coil. In addition, it maintains a constant drive voltage to each load device, regardless of the load variations in local or adjacent cubes. The constant voltage design eases local power management. A prototyped IPT cube array is manufactured and tested to validate the proposed idea. This fission-type IPT system makes a valuable exploration of the 3D IPT technology toward future ubiquitous and reconfigurable IoT arrays.

An Underwater Inductive Power Transfer System with a Compact Receiver and Reduced Eddy Current Loss

Inductive power transfer (IPT) technology is widely used in autonomous underwater vehicles (AUVs) to achieve safety and flexibility. However, the eddy current loss (ECL) will be generated in the seawater due to the high-frequency alternating current in the transmitter and receiver. An underwater IPT system with a series-none (SN) compensation topology is proposed in this paper to achieve a compact receiver for AUVs and reduce the ECL. The analytical model of the IPT system is built to analyze its transfer performance. The phase difference between the transmitter and receiver current of the SN compensation topology is larger than 90° compared to that of the conventional series-series (SS) topology, which can significantly decrease the magnitude of the electric field caused by coil currents; thus, the eddy current loss is reduced. Moreover, the optimal load resistance of the seawater IPT system is lower than that in the air, and the SN compensation topology has a more compact receiver with no compensation capacitor in the receiving side, which can save the internal space in the AUVs. An experimental prototype based on the SN topology is built, and the experimental results have verified the analysis.

Development of self-charging unmanned aerial vehicle system using inductive approach

This paper presents an alternative approach to power up unmanned aerial vehicle (UAV) system using inductive approach. The main issue of utilizing UAV in any application especially in precision agriculture is the lifetime of the battery. This limits the flight time of the UAV which makes the system is unable to be efficiently applied for precision agriculture purpose. Hence, this paper proposes a new approach of powering UAV system by using so called inductive power transfer (IPT) technology. Through this approach, the system can be powered up wirelessly with no physical link in between transmitter and receiver. To be specific, class E inverter circuit has been designed together with impedance matching circuit to ensure higher efficiency is obtained. Finally, a prototype of IPT system for powering up the UAV system was successfully developed, which is able to transmit 23.32 W of power at 1 MHz operating frequency from 12 V input supply. The system achieved up to 95.73% efficiency.