Resonant Inductor Research Articles

Systematic analysis of wireless energy transmission methods

Wireless energy transfer technology is a new type of power transmission technology that utilizes electric and magnetic fields as mediums. In contemporary society, there are three main methods of wireless energy transfer: magnetic coupling resonance, microwave radiation, and electromagnetic induction. Each of these methods has its unique advantages and limitations, leading to different application scenarios in practical life. This article provides a detailed introduction to the basic structure and principles of magnetic coupling resonance, microwave radiation, and electromagnetic induction wireless energy transfer. Through comparative analysis of the characteristics of these three transmission methods, it explores their specific applications in various industries and life domains. Additionally, the article examines the challenges faced by today's wireless energy transfer technology, such as transmission efficiency, safety, cost, standardization, and technical difficulties. Finally, the article envisions the future development of wireless energy transfer technology, suggesting that as the technology continues to progress and improve, it will see broader application, bringing more convenience to people's lives and promoting integration with other fields to form more efficient and sustainable solutions.

Analysis and Modeling of Fractional Order LC Series Resonant Boost Converter Based on Fractional Calculus and Laplace Transform

ABSTRACTBased on the fractional‐order (FO) characteristics of inductors and capacitors, many basic PWM DC–DC converters are defined and modeled by FO calculus in previous studies, but the research of FO resonant dc converters is still in its early stage. Therefore, this paper adopts FO calculus and Laplace transform to model and analyze a ZCS boost converter with an LC resonant tank, which mainly focuses on the influence of the FO component on the soft switching characteristics, converter efficiency, and output voltage gain of this isolated dc converter. This paper extends the topology to the fractional order domain and conducts FO modeling. The order of the resonant inductor and capacitor will affect the amplitude/phase of the resonant current and then affect the converter ZCS characteristic. The analysis demonstrates that the reduction of FOI and FOC order is not conducive to the ZCS of switching devices and converter efficiency. Based on the voltage and current relationship of the FO LC resonant tank, a parameter design guideline is presented. Numerical tools are used to solve the FO output voltage gain and draw the gain curve. And the order of FOI and FOC provides new flexibility for the converter output gain and soft switching design. Finally, simulations and a 360 W hardware experimental prototype are conducted to verify the accuracy and effectiveness of theoretical analysis.

Evaluating a novel bidirectional soft-switching DC-DC converter for electric vehicles

This research aims to build unique zero voltage transition (ZVT) non-isolated bidirectional DC-DC converters for hybrid electric vehicle battery storage. First, a high-voltage gain bidirectional converter (BDC) is examined. This converter can soft-switch insulated gate bipolar transistors (IGBTs). The primary insulated-gate bipolar transistors (IGBTs) are operated under zero-current conditions throughout the turn-on to turn-off commutation phase to reduce switching losses and increase efficiency. A soft-switched cell with a resonant inductor, capacitor, and additional IGBTs achieves zero-current turn-off. A new converter uses insulated-gate bipolar transistors with zero-voltage transition operation. Soft-switched cells improve the hard-switched bridgeless DC-DC converter (BDC). Resonant inductors, capacitors, and auxiliary switching devices make up the soft-switched cell. Soft-switched cells enable zero voltage turn-on of primary insulated-gate bipolar transistors. This converter charges the battery in buck mode and boosts it to provide the necessary output voltage. This study examined a 70 V/300 V power system's high-gain bidirectional converter (BDC) design simulation. The converter was tested at 50 kHz with 800 W output power. The high-gain soft-switched BDC has 96.5% boost and 97% buck efficiency. Operating principles, design analysis, and simulation assessments are included in this study.

Dual Side Field Oriented Control of Slip Ring Induction Motor

Dual Side Field Oriented Control of Slip Ring Induction Motor

A bidirectional DC/DC converter for renewable energy source-fed EV charging stations with enhanced DC link voltage and ripple frequency management

The amount of electricity that the grid must supply has increased as the number of electric vehicles (EVs) has increased. The best way to minimize power pollution between the automobile and the grid is to use an EV charging station to establish a bidirectional connection with an energy storage unit (ESU). This paper proposes a bidirectional DC/DC converter for battery available at the renewable energy sources (RES) fed charging station. This bidirectional DC-DC converter has important advantages such as dc link voltage stress reduction and the ripple frequency of inductor current is two times of the converter's switching frequency. The proposed converter consists of two identical Zero Voltage Transition (ZVT) cells and each cell includes a capacitor, two resonant inductors and a supplementary switch which is combined with the traditional three level topology that enables both buck and boost operating modes. The simulation-based analysis has been done using MATLAB/Simulink. The simulation results have been verified with the help of experimental setup is presented for the converter module for validating the charging station.

Investigating the Effects of Induction Heating on a Submerged Hollow Cylindrical Element

ABSTRACTThis article proposes an induction heating element that addresses heat transfer and thermal homogenization while being fully submerged in a liquid, specifically focusing on heating of water as a case study. The design calculations, fabrication, and realization of a resonant induction heating system that heats the proposed heating element are presented. The geometric shape of proposed heating element is a hollow cylinder that maintains structural strength while delivering required thermal energy because of an external time‐varying magnetic field. Detailed mathematical modeling of the proposed heating element's equivalent electric circuit has been presented while considering physical parameters including diameter, thickness, height, material properties, magnetic field frequency, and skin effect. A laboratory scale prototype of the induction heating system including the proposed heating element has been built, and experiments have been demonstrated. The experimental results of the working induction heating resonant inverter and RLC resonant circuit inductance and capacitance with induction load are presented. Additionally, the results of thermographic images and temperature–time profile of the water sample, which was heated using the proposed heating element, are provided to demonstrate the heating element's reliability and practicality. This research contributes to the field of induction heating technology by investigating a heating element that is submerged in a liquid medium, resulting in a uniform temperature distribution throughout the liquid. The conventional method of heating water in a stainless steel cup‐shaped container is an inefficient heat transfer process. In stainless steel cup‐shaped containers, a portion of the energy input used to boil the water is lost to the environment through the surface area of the container that is not in direct contact with the water. This heat loss occurs due to the container's design, which exposes a large surface area to the surrounding environment, allowing thermal energy to dissipate through conduction, convection, and radiation.

Crisis-induced vibrational resonance in a phase-modulated periodic structure.

Double vibrational resonance is reported for a driven oscillator in a periodic structure of the Josephson junction type with high-frequency phase modulation. We identify two distinct phase modulation effects, namely, resonant induction and resonant amplification, leading to the appearance of a double resonance. We analyze these vibrational resonance phenomena theoretically and numerically, and we show that the origin of the induced resonance is traceable to a transition from periodicity to quasiperiodicity associated with an attractor-merging crisis.

A Zero‐Voltage Switching Three‐Level Nonisolated Bidirectional DC/DC Converter With a Lossless Passive Component Auxiliary Circuit and Design‐Oriented Analysis

ABSTRACTA three‐level bidirectional buck/boost converter (TLBBBC) is suitable for power electronic systems with a high‐voltage DC link for its switches with half voltage. In order to achieve higher efficiency, a novel zero‐voltage switching (ZVS) TLBBBC is proposed in this paper to enable operation with higher switching frequencies. In the proposed ZVS TLBBBC, two identical ZVS cells, each composed of a resonant inductor, two snubber capacitors, and two resonant capacitors, are integrated with the conventional three‐level (TL) topology to enable soft switching in all four switches in both buck and boost modes. Here, one advantage is that soft‐switching conditions are ensured under conventional control methods without using the auxiliary switch or complex control methods. In addition, the soft‐switching region is derived, clearly illustrating the relationship between the duty cycle ratio and the power inductor current that ensures the soft‐switching condition. Hence, the soft‐switching region is beneficial for assisting in ZVS cell design and guiding the converter in running in ZVS. Then, the operation and design considerations of the proposed topology are analyzed in detail. Finally, the experimental results of an 800‐W prototype for both the boost and buck modes are presented to confirm the theoretical analysis.

Research on the energy transmission mode of a three-port DC–DC converter based on ultra-thin silicon steel

With the introduction of China’s “Carbon Peaking Action Plan Before 2030,” the transformation of the power industry has released huge opportunities and potential. The DC distribution network can well-coordinate the contradiction between distributed power and grid access, fully develop the benefits of distributed energy, and become a new direction for the development of the power industry. However, the current traditional DC–DC converters have problems such as single-topology structure and low power density, which can only complete one-way transmission of energy; hence, the distributed energy cannot be fully utilized. Addressing the problem of distributed energy transfer, this paper is based on a three-port DC–DC converter for a low-voltage DC distribution network to realize energy transfer between the DC distribution network, distributed energy, and low-voltage load. First, the energy transfer modes of the three-port DC–DC converter are introduced. Combined with the converter topology and energy transfer mode, a simplified equivalent model of the converter is established. The voltage gain characteristics and frequency characteristics of this converter are studied. Furthermore, the effects of the excitation inductance to primary resonance inductance ratio parameter k and quality factor Q on the voltage gain characteristics of the converter are discussed. On this basis, the resonant cavity design of the converter is based on the optimal selection of parameters k and Q so that the converter can meet the voltage gain requirements in both forward and reverse operations. The simulation results under different loads verify the reasonableness of the resonant cavity component selection.

Experimental Induction of Extreme Indented Growth Rings (Hazel Wood) in Pinus halepensis Miller by Wide and Long Parallel Bark and Vascular Cambium Woundings.

Indented growth rings were found long ago to be experimentally induced in Pinus halepensis Miller by thin parallel axial scratching of the bark up to the vascular cambium with a sharp blade. Here, we show that when the bark and vascular cambium of P. halepensis are wounded by wide and long parallel axial wounds ("windows") rather than by thin scratches, the induced indented growth rings become dramatically more indented. All ten trees that were wounded by long parallel "windows" responded with very strong growth (especially in the first two years) that resulted in the formation of very conspicuous, extremely indented growth rings in the wood formed in between the long and wide woundings. This is true for both the trunks that were wounded all around their circumference and those that were wounded only in part of their circumference. We also suggest further lines of research.

Enhancing electromagnetic shielding property and absorption coefficients via constructing electromagnetic rings in janus composites

Polymer based electromagnetic wave (EMW) shielding materials with high conductivity have excellent electromagnetic shielding properties, but also exhibit high reflection of EMWs, resulting in inevitable secondary electromagnetic pollution. EMW shielding materials with low reflection have extensive potential applications in the next generation of anti-EMW equipment. Herein, a production strategy combining three dimensional (3D) printing technology and solution casting method was proposed to prepare polylactic acid (PLA)@multi-walled carbon nanotubes (MWCNT)/polydimethylsiloxane (PDMS)@carbonyl iron powder (CIP) absorptive electromagnetic shielding Janus composites with a ring-shaped electromagnetic synergistic structure (spiral rings or concentric circular rings). By utilizing PLA and MWCNTs as primary components, a 3D integrated framework that combines a highly conductive reflector and a ring inductance structure can achieve significant EMW shielding performance with low reflection. With PDMS as a matrix and magnetic CIP as functional fillers, a strong magnetic permeability network is provided around the ring inductance frame. The magnetic loss resulting from electromagnetic cooperative ring structure further enhances microwave absorption capacity. The composite materials, benefiting from the synergistic interaction between the electromagnetic rings and the reflector, demonstrate excellent impedance matching and efficient EMW shielding capabilities. Specifically, the PLA@MWCNT/PDMS@CIP Janus composites with ring structure exhibit a notable EMW shielding effectiveness (SE) of 31 dB and a reflection coefficient as minimal as 0.3. Therefore, this study presents a powerful approach to the development of low-reflective materials with high EMW SE, promising potential applications in the next-generation intelligent electronic devices.

A novel seven‐level inverter with high gain and reducing spike current capabilities

SummaryThis paper describes a novel seven‐level (7L) inverter. The suggested topology offers a 7L output voltage and a threefold gain by using proper capacitor values. The suggested topology reduces the spike current induced by the capacitor by the use of a resonant inductor. The suggested inverter's performance under various loads and situations is compared with those found in existing literature. The simulation findings confirm the system's strong performance in terms of component count, control circuit simplicity, and possible cost reductions, while retaining similar or enhanced performance metrics as compared with the aforementioned topologies. A laboratory setup is used to validate the feasibility of the suggested topology and provide solid evidence of its effectiveness. Furthermore, discussions about the possible uses of this structure in energy conversion are conducted.

Barrier-free subwavelength multi-channel topological acoustic interlayer under direct resonance induction

In this paper, a new topological acoustic interlayer is proposed, which is formed by combining multi-order resonators in the form of the triangular lattice in the normal direction of the acoustic interlayer. Through the strong resonance of the resonator, the distribution of modes in the acoustic interlayer is directly induced to form a combination of modes with different topological states to support the subwavelength multi-channel lossless directional acoustic transmission in barrier-free space. Since there are no scatterers, not only can the required frequency band be directly achieved through the resonance frequency of the resonator alone, but also the background medium space in which the acoustic wave transmitting is a uniform medium, so the transmission is secret and the structure is ventilated. More importantly, there is more space in the normal direction of the barrier-free interlayer for design sub-wavelength multi-channel transmission. Furthermore, the random obstacles in interlayer do not affect the transmission under the pseudo spin modes. Finally, experimental verification is carried out. This research paves the way for the engineering application of multi-band acoustic antennas, covert communication, ventilated devices and other multi-functional devices, and will bring new enlightenment to the fields of elastic wave, light wave and electromagnetic wave.

Self-Frequency Tracking for Fixed-Ratio Switch-Capacitors in Data Center Application without Extra Sensors

As research into data centers progresses, the importance of resonant switched-capacitor converters in power supply design becomes more evident. Practical applications reveal that the values of resonant capacitors and inductors may deviate from their nominal values due to various factors, leading to resonant frequency instability. This instability poses a challenge to power electronics technology, affecting system reliability and performance. This paper analyzes the effect of frequency deviation on system functionality, identifies the relationship between output voltage and switching frequency, and proposes a self-tracking frequency strategy to address this issue. Through experimental validation, this approach shows that it maintains synchronization between switching and resonant frequencies, reducing losses associated with frequency misalignment. Simulation and experimental results validate the converter’s stable operation and its ability to achieve zero-voltage and zero-current switching.

Analysis and design of an efficient soft‐switching inverter with asymmetric auxiliary circuits

SummaryThe paper designs an efficient three‐phase soft‐switching inverter with asymmetric auxiliary circuits, which is beneficial for further miniaturization and efficiency optimization. Only two auxiliary switches, one resonant inductor, and three resonant capacitors make up simple asymmetric auxiliary circuits of each phase, contributing to the reduction of power loss and hardware cost. As soon as the simple auxiliary circuits get involved in the operation of the designed inverter, main switches can realize zero‐voltage switching within the entire load range. The reduction of power loss of auxiliary circuits and main switches is conducive to further efficiency optimization. The paper expounds every operating status during one switching period. The relevant experimental waveforms make known that switching devices can realize soft‐switching. The efficiency reaches 99% at rated operation status of the designed inverter, confirming that the designed inverter has superiority over comparison objects in the experiment with regard to the efficiency. Thus, the structural simplification of auxiliary circuits is an effective method for further miniaturization and efficiency optimization.

Research on Wireless Power Transfer Method for Intelligent Sensing Device of Non-Directly Buried Distribution Cables

This paper presents a study on the impact of circuit parameters on the transmission of electrical energy in wireless power transfer systems designed for intelligent sensing devices within the urban electric power Internet of Things (IoT). Relying on the essential principles of resonant mutual inductance models, the paper conducts an analytical investigation into the phenomena of power-frequency splitting characteristics, efficiency-frequency splitting characteristics, and efficacy synchronization characteristics within wireless energy transmission technologies. The investigation includes a detailed analysis of a wireless power transfer system model operating at 100 kHz, delineating how varying circuit parameters influence the system’s efficiency. Via the utilization of graphical software and computational programming for simulation modeling, this research delved into the dynamics between key parameters such as equivalent load and coupling coefficient and their influence on distinct splitting phenomena. This rigorous approach substantiated the validity of the proposed power-frequency and efficiency-frequency splitting characteristics outlined in the study. Based on the analytical results, it is shown that selecting an appropriate equivalent load or utilizing impedance matching networks to adjust the equivalent load to a suitable size is crucial in consideration of the system’s output power, voltage withstand level, and transmission efficiency. The research findings provide a theoretical basis for the design of wireless power supply systems for non-directly buried cable front-end sensing devices.

Novel Series-Parallel Phase-Shifted Full-Bridge Converters with Auxiliary LC Networks to Achieve Wide Lagging-Leg ZVS Range

Under light load conditions, the phase-shifted full-bridge (PSFB) converter often has difficulty in realizing the zero-voltage switching (ZVS) of the lagging-leg by relying on the energy of its resonant inductor; however, for the series-parallel PSFB converter applied in high-power applications, the lagging-leg still has the problem of difficult realization of ZVS. Based on this, the paper analyzes the reasons why the series-parallel PSFB converter has difficulty in achieving ZVS for the lagging-leg under light and heavy loads. Under interleaved control, the ZVS of the lagging-leg over the full load range is realized by adding an auxiliary LC branch at the midpoint of the lagging-leg of both submodules. Based on the double-bridge input-parallel-output-series (IPOS) PSFB converter, analyzing the working principle of the circuit after adding the auxiliary LC branch and extending it to the series-parallel PSFB converter. The design requirements of the LC auxiliary branch of the dual-bridge series-parallel PSFB converter are given and the effects of the LC auxiliary branch on the module operating state and device stress are analyzed. On this basis, an extension is carried out to give the working principle and design method of the auxiliary LC branch of the N-bridge series-parallel PSFB converter. Finally, a 100 kW Matlab/Simulink simulation model verifies the superior performance of the proposed LC auxiliary branch to realize the lagging-leg ZVS of the series-parallel PSFB converter under light and heavy loads and achieves a 1.09% peak efficiency improvement at rated load.

Analysis and design of voltage‐source parallel resonant class E frequency multiplier

AbstractIn this paper, the analysis and design process of the voltage‐source parallel resonant class E frequency multiplier with a 50% duty ratio is proposed. The proposed circuit adopts two series resonant filters for reducing the interference of harmonics to the output waveform and achieves zero‐voltage switching (ZVS) and zero‐voltage derivation switching (ZVDS) conditions. The design equations for the proposed circuit are given in detail. The new type class E frequency multiplier can operate at lower transistor voltage stress, higher operating frequency, and larger output power. Meanwhile, the volume and weight of the measured circuit are greatly decreased compared to the conventional class E frequency multiplier. To demonstrate the analysis process, the circuit operating at 1 MHz is fabricated and measured. Compared to the traditional class E frequency multiplier, the transistor peak voltage is reduced by 47.9%, the diameter of the resonant inductor core is decreased by 56.2%, and the measured efficiency can reach 95.1%. The theoretical and simulated results are all agreed with the experimental results.

Maximum Efficiency Point Tracking Algorithm for Resonant Full-Bridge Converter in Charging Applications

In this paper, a novel maximum efficiency point tracking algorithm is proposed for a resonant DC-DC power converter in charging applications. Based on a total harmonic analysis (THA), a method for minimizing the harmonic content of the input AC current is investigated. An online algorithm is proposed for achieving the maximum efficiency at the whole charging spectrum, by controlling the angle under which zero-voltage switching occurs. The suggested control algorithm is simple to implement with very low computational complexity. Additionally, an effective winding method is proposed for increasing the leakage inductance without greatly increasing the air gap, thus eliminating the need for additional resonant inductors. A prototype converter of 2kW|20A is implemented for verifying the proposed method and 98% maximum efficiency is achieved.

Double B-type magnetic integrated transformer based input-parallel output-parallel LLC resonant converter modules

The LLC resonant converter used in high-power situations suffers from the problems of high conduction loss and current stress, which can be solved using input-parallel output-parallel (IPOP)-connected converter modules. However, this leads to a multiple increase in the number of magnetic components, which reduces power density. Magnetic integration technology is an effective way to reduce the volume of converters. Currently, the magnetic integrated transformer based on EE-type cores is widely used to realize miniaturization, and it uses leakage inductance instead of resonant inductance to improve power density. However, leakage inductance is difficult to control, and the external radiated magnetic field will produce serious eddy current loss and electromagnetic interference. This article proposes a novel double B-type magnetic integrated transformer, which can integrate the magnetic components of two LLC resonant converters simultaneously and where the resonant inductances are wound independently. The structure contains four low reluctance branches, which are used as the cores of the transformer and the resonant inductance. The decoupling integration method, which integrates the four components into a single core, has been used to increase core utilization and improve power density. On this basis, the transformer’s high- and low-voltage windings are cross-arranged to reduce the magnetic field intensity in space, further decreasing the loss and electromagnetic interference. Compared with the EE-type magnetic integrated transformer, the volume of the proposed structure is reduced by 5.9%. A 400W experimental prototype is built, and the results verify the validity of the design.