Inductive Energy Transmission Research Articles

Performance improvement of inductive coupling system using ferrite materials

Ferrite Encumbered inductive coupling-based energy transmission is interestingly being investigated both theoretically and experimentally as an alternative technique of delivering power through human skin and body for wireless excitation of implantable electronic devices. In the explored system, to enhance the efficiency, the magnetic flux produced by the transmitting coil can be improved focused through the ferrite loaded printed receiving coil by cautious symmetrical placement of ferrite materials. The properties of ferrites include high magnetic permeability and high electrical resistance. In this paper, a ferrite configuration is estimated using Finite Element Method, and an efficient model is nominated for construction and laboratory testing. The proposed technique entails an energy transfer efficiency of ∼48.2% at maximum output power of 248 mW and resonant frequency of 120 kHz over a separation gap of 3 cm. The real-time body temperature of human has been recorded through the energized temperature sensor and corroborated with a calibrated system which ensures the precision of the developed prototype system. The real time data collected in the laboratory are in good agreement with the simulation results, which specify that the laboratory physical prototype and circuit closely followed to the physical and electrical parameters of the simulation. The ferrite loaded resonant inductive coupling technique is considered as a feasible and supportive substitute to the conventional technique for implantable electronic sensors.

ОГЛЯД ОСНОВНИХ ТЕХНОЛОГІЙ БЕЗДРОТОВОЇ ЗАРЯДКИ НАКОПИЧУВАЧІВ ЕНЕРГІЇ ДЛЯ МАЛОПОТУЖНИХ СИСТЕМ

Urgency of the research. The development of new topologies, methods for calculation and optimization of semiconductor transducers for WPT systems will allow to increase the electric energy transmitted wirelessly, extend the range of frequency regulation, which will reduce the time spent on recharge of electric vehicles and increase the convenience of using WPT systems by reducing the sensitivity to precise positioning of receiving and transmitting elements, which will become a prerequisite for more active introduction of electric vehicles and electric vehicles. In conditions of different ecological, demographic, economic situation in the world, the individual electric transport is becoming more and more popular. Solving the set tasks will create preconditions for the implementation of WPT in many spheres of society, both in Ukraine and in the world as a whole (private transport, military equipment and equipment, household electronics, etc.).Target setting. Now methods of wireless power transfer (WPT), based on the phenomena of electrostatic and electromagnetic induction, are widely used in various applications. WPT method is widely used today in low-power systems - wireless charging of mobile phones, razors, toothbrushes, low-power vehicles. The main constraints of such systems are low efficiency at high transmission distances and relatively large mass-size parameters of the elements, which in turn leads to high cost of WPT system. Recently, there are more and more consumers who need to transmit contactless method of electric energy from units of kilowatts or higher.Actual scientific researches and issues analysis. The analysis of the state of research shows that the subjects of research on the improvement of wireless charging systems are constantly expanding and are extremely relevant, in particular, abroad. Especially considering the development of electric vehicles, there is growing interest in wireless charging of vehicles. There is also a solution to the inductive power transmission system for low and high voltage power supplies.Uninvestigated parts of general matters defining. If static and dynamic charging of electric cars is devoted to many articles and developments, then the individual means of travel are paid less attention, so the design of low-voltage wireless charging for electric bikes, electric scooters, and velomobiles is a promising area of research. Modern research is aimed at achieving lower cost and improving the efficiency of wireless charging systems for such vehicles.The research objective. The main tasks are to review and compare existing topologies, calculation methods, and optimization of WPT systems.The statement of basic materials. In the first part of the article general information about principles of operation and application of capacitive and inductive method of wireless transmission of energy are considered, advantages and disadvantages, efficiency are presented. The emphasis is on magnetic resonance communication, the main compensating topologies are considered. Graphs of the dependence of the transfer function of the WPT on the frequency for the serial-serial resonance scheme are constructed. The probable dependence of the distance between the transmitter and receiver is separately presented. In the second part of the article an analysis of the existing power semiconductor topology WPT based on inductive coupling and various compensating topologies. Initially, inductive energy transmission systems for low voltage power supplies are analyzed. The topologies of primary and secondary dc-dc converters are selected and compared from the point of view of the required nominal power and efficiency. The WPT system based on the current inverter and the compensating resonance PS-topology for electric vehicles and devices for charging the battery are analyzed. An interesting article is considered, which analyzes and compares the proposed onboard electric vehicle charger based on an impedance link with a conventional OBC. The following is a variant of the topology and cost-effective design of antennas for the transmission of wireless energy in electric scooters. In addition to purely circuit design, other solutions in the field of power electronics are considered, which will improve the efficiency of wireless power transmission. A new high-performance planar approach is presented for the integration of all magnetic components of the primary-parallel isolated enhancer converter into the structure of the form E-I-E-core planar integrated magnetic (PIM).Conclusions. The article gives an overview of the main technologies of wireless charging of energy storage devices for low-power systems. It has been found that the inductive mode of energy transmission is most effective now. At the same time, it should be noted that with increasing transmission distance, efficiency falls significantly. The improvement of the geometry of magnetic components is the main focus of research in this direction. The main topological solutions of power electronics circuits are reduced to the implementation of four main methods of compensation for obtaining sinusoidal voltage. That is, for different tasks, different topologies are selected with those or other modifications, depending, first of all, on the power that needs to be transmitted and the load. Further research may be aimed at reducing the number of semiconductors and alternative ways to realize compensation.

Two-Stage Design Method for Enhanced Inductive Energy Transmission with Q-Constrained Planar Square Loops.

Q-factor constraints are usually imposed on conductor loops employed as proximity range High Frequency Radio Frequency Identification (HF-RFID) reader antennas to ensure adequate data bandwidth. However, pairing such low Q-factor loops in inductive energy transmission links restricts the link transmission performance. The contribution of this paper is to assess the improvement that is reached with a two-stage design method, concerning the transmission performance of a planar square loop relative to an initial design, without compromise to a Q-factor constraint. The first stage of the synthesis flow is analytical in approach, and determines the number and spacing of turns by which coupling between similar paired square loops can be enhanced with low deviation from the Q-factor limit presented by an initial design. The second stage applies full-wave electromagnetic simulations to determine more appropriate turn spacing and widths to match the Q-factor constraint, and achieve improved coupling relative to the initial design. Evaluating the design method in a test scenario yielded a more than 5% increase in link transmission efficiency, as well as an improvement in the link fractional bandwidth by more than 3%, without violating the loop Q-factor limit. These transmission performance enhancements are indicative of a potential for modifying proximity HF-RFID reader antennas for efficient inductive energy transfer and data telemetry links.

Primary Side Circuit Design of a Multi-coil Inductive System for Powering Wireless Sensors

Circuit design of the primary side is decisive for the efficiency of inductive energy transmission. In order to maximise the transmitted energy to the load, primary side DC/AC inverter and system resonance topologies should be investigated. This paper presents an inverter for a multi-coil inductive system with different system resonance topologies for a low voltage and a relative high frequency of 1.2MHz. A comparison between half-wave and full-wave inverters is carried out for both Series-Series (SS) and Parallel-Parallel (PP) topologies. Results show that the full-wave inverter with PP topology is adequate primary side circuit for multi-coil inductive system and reaches a sending power 10 times higher than a classical half wave inverter.

Influence of Angular Coil Displacements on Effectiveness of Wireless Transcutaneous Inductive Energy Transmission

The effect of angular displacements on wireless transcutaneous inductive energy transmission was studied using computational modeling. It is shown that for a geometry characteristic of transcutaneous energy transmission (distance between centers of flat coils less than the radius of the coils, angular displacement in the range of 0-30°), the angular displacement can lead to an increase in transmitted power. Therefore, it is essential to develop methods of preventing transmission of excessive power to the receiver portion of a wireless energy transmission system to avoid overheating of implanted components.

Combination of a contactless power supply with an electromagnetic guiding for a vertical transportation system

A contactless energy transmission system is essential to supply on-board systems of magnetic levitated vehicles without physical contact to a guiding rail e.g. in clean room environment. This paper introduces a combined contactless power supply (CPS) and electromagnetic guiding system (MGS). The actuator of the linear guiding system is part of an inductive energy transmission. With this approach two devices are integrated in one entity. The hybrid actuator consists of an omega shape iron yoke with permanent magnets and coils on its lateral arms. A concentrated primary winding is added to the elevator shaft and a secondary winding is wound on the central arm. Hereby a superposition of the MGS flux and the CPS flux emerges in the magnetic circuit of the actuator. A decoupling of the two systems is achieved by the high frequency of the CPS flux compared to the MGS flux. The proposed system requires less construction space and weight compared to existing energy transmission systems.

A Comparative Study Between Novel Witricity and Traditional Inductive Magnetic Coupling in Wireless Charging

A non-radiative energy transformer, commonly referred as Witricity and based on `strong coupling' between two coils which are separated physically by medium-range distances, is proposed to realize efficient wireless energy transfer. The distance between the resonators can be larger than the characteristic sizes of each resonator. Non-radiative energy transfer between the first resonator and the second resonator is facilitated through the coupling of their resonant-field evanescent tails. The proposed system operates as traditional inductive magnetic coupling devices when the operating frequencies are not the resonant frequency. Corresponding finite element analysis (FEA) and experiments have been carried out to facilitate quantitative comparison. Compared with typical magnetic inductive coupling energy transmission devices, the efficiency of the proposed system is much higher. This investigation indicates that it is feasible to use wireless energy transfer technology to recharge batteries, particularly in implant devices.

A novel resonant inductive magnetic coupling wireless charger with TiO2 compound interlayer

A nonradiative energy transformer exploiting TiO2 nano-powder and (C4H6O2)x latex as a combined interlayer is proposed. The transformer works on ‘strong coupling’ between two coils (i.e., resonators), which are physically separated from each other by distances that are longer than the characteristic sizes of each resonator, to realize efficient wireless energy transfer. Nonradiative energy transfer between the two resonators is facilitated through the coupling of their resonant-field evanescent tails. Finite element analysis and experiments have been carried out to facilitate quantitative comparison. The efficiency of the proposed system is 70.6% at 5 cm and 26.3% at 15 cm at an operating frequency of 1.74 MHz. When compared with typical magnetic inductive coupling energy transmission devices with low dielectric constants, the efficiency of the proposed system is much higher.

Experimental Implantation and Long-term Testing of an Intraocular Vision Aid in Rabbits

Objective To develop an intraocular vision aid to provide artificial vision in severely traumatized eyes, where neuroretinal function could be preserved but irreversible anterior segment opacification resulted in blindness. Methods The basis of an intraocular vision aid is in principle a telemetric circuit to bridge the opaque cornea and to allow for artificial light stimulation of the retina. The visual prosthesis comprises an external high-dynamic range complementary metal oxide semiconductor camera and digital signal processing unit and an intraocular miniaturized light-emitting diode array to project the image onto the retina. For in vivo testing of long-term function and biocompatibility, silicone-encapsulated active photodiodes were implanted in 13 pigmented rabbits and were followed up for up to 21 months. Results Lens extraction and stable fixation of the device in the ciliary sulcus were successful in all cases. For up to 21 months inductive energy transmission and wireless stimulation of the implants could be maintained. Electrophysiologic data and histology demonstrated a good tissue biocompatibility in the long-term follow-up. Conclusion The results demonstrate the general feasibility and biocompatibility to implant and fixate an intraocular light-emitting diode prosthesis. Inductive energy transmission to the intraocular device and wireless light stimulation are assured in the long term but depend on meticulous water-impermeable encapsulation of the delicate microelectronic components. Clinical Relevance An intraocular vision aid compound system with a high-resolution light-emitting diode matrix might be a future treatment option to restore vision in blind eyes with severe anterior segment disorders.

Experimental Implantation and Long-term Testing of an Intraocular Vision Aid in Rabbits

To develop an intraocular vision aid to provide artificial vision in severely traumatized eyes, where neuroretinal function could be preserved but irreversible anterior segment opacification resulted in blindness. The basis of an intraocular vision aid is in principle a telemetric circuit to bridge the opaque cornea and to allow for artificial light stimulation of the retina. The visual prosthesis comprises an external high-dynamic range complementary metal oxide semiconductor camera and digital signal processing unit and an intraocular miniaturized light-emitting diode array to project the image onto the retina. For in vivo testing of long-term function and biocompatibility, silicone-encapsulated active photodiodes were implanted in 13 pigmented rabbits and were followed up for up to 21 months. Lens extraction and stable fixation of the device in the ciliary sulcus were successful in all cases. For up to 21 months inductive energy transmission and wireless stimulation of the implants could be maintained. Electrophysiologic data and histology demonstrated a good tissue biocompatibility in the long-term follow-up. The results demonstrate the general feasibility and biocompatibility to implant and fixate an intraocular light-emitting diode prosthesis. Inductive energy transmission to the intraocular device and wireless light stimulation are assured in the long term but depend on meticulous water-impermeable encapsulation of the delicate microelectronic components. Clinical Relevance An intraocular vision aid compound system with a high-resolution light-emitting diode matrix might be a future treatment option to restore vision in blind eyes with severe anterior segment disorders.

A contactless electrical energy transmission system for portable-telephone battery chargers

A high-performance contactless electrical energy transmission (CEET) technique which employs the inductive energy transmission principle is described. The proposed technique enables the implementation of high-efficiency high-power-density fully regulated CEET systems suitable for applications with a wide input and load range. A high efficiency of the system is achieved by recovering the energy stored in the leakage inductances of the transformer by incorporating them in the operation of the circuit, and by employing high-frequency-inverter and controlled-rectifier topologies that allow a controlled bidirectional power flow through the transformer. In addition, a feedforward variable-switching-frequency control of the inverter is used to maintain approximately constant power transfer through the transformer with the input voltage changes, whereas the output-side rectifier employs a local pulsewidth-modulation control to achieve a tight regulation of the output in the presence of load variations. Specifically, the described CEET system is suitable for use in universal-input battery chargers.

Modeling and test of contactless inductive energy transmission

More and more applications require contactless energy transmission: machine tools (rotating table, x–y tables), robotics, electric vehicle loading systems, high speed transportation, a.s.o. The electromagnetic inductive technique is a good solution in a wide range of power. The aim of this paper is to assess solutions for electric vehicles and rotating systems. This way, ironcore rotative transformer and ironless linear transformer are considered. The specific methodology and equations to design such transformers will be presented. A parametric analysis will show the main limits and finally, some design results will also be presented for a high speed underground transportation system – the Swissmetro project.