Inductive Coupling Research Articles

Unified Model of Peak Current Mode Controlled Coupled SIDO Converters

Coupled inductor single-input–dual-output (CI-SIDO) converters are promising converters used in the applications that demand multiple voltage supplies due to their high efficiency and small volume. However, this class of converters suffers from poor cross-coupling and cross-regulation issues, which affects the dynamic performance and stability. These issues can be suppressed with peak current mode control because of its faster dynamic response. To design the controller and study dynamic performance, a small-signal model of the system is essential, which consists of a converter model and current modulator model. However, developing the current modulator model for PCM controlled CI-SIDO converters is challenging because it consists of two reference current for two inductor currents each consisting of three slopes. No literature is available that derives a unified model of PCM controlled CI-SIDO converters. Therefore, this article proposes a unified small-signal model for PCM controlled CI-SIDO converters. The proposed model is applicable to three topologies of CI-SIDO converters, i.e., CI-SIDO buck, CI-SIDO boost, CI-SIDO boost and buck converter. The proposed unified model is a useful tool to study the dynamic performances, stability, and design outer controllers. Finally, the accuracy of the proposed unified model is verified by performing simulation and experiment of PCM controlled CI-SIDO converters considering inner-loops closed.

A Cycle by Cycle FSK Demodulator With High Sensitivity of 1% Frequency Modulation Index for Implantable Medical Devices

This paper presents a cycle by cycle Frequency Shift Keying (FSK) demodulator, able to demodulate a FSK signal with 1% frequency modulation index (MI), in a single cycle. Based on the proposed demodulation scheme, a high rate data transmission link can be established through a high-Q inductive coupling link, breaking the basic tradeoff between the power transfer efficiency (PTE) and data rate in single carrier wireless power and data transfer systems. Designed and simulated with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.18\mu m$ </tex-math></inline-formula> CMOS process, the proposed FSK demodulator, detects successfully a 5Mbps data with a carrier frequency of 5MHz. A test chip is fabricated in 180nm CMOS technology. Measurement results shows that the demodulator is able to demodulate the cycle-by-cycle modulated FSK signals with low modulation index of 2.5%, with a BER of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.24\times 10^{-5}$ </tex-math></inline-formula> .

A Single Switch High Step-Up DC-DC Converter Based on Tri-Winding Coupled Inductor for Renewable Energy Applications

This article introduces a novel nonisolated single-switch high step-up DC-DC converter using a tri-winding coupled inductor (TWCL) for renewable energy applications such as PV systems. Also, the voltage multiplier cell (VMC) is used to attain a high voltage gain. The used VMC acts as a passive clamp circuit and reduces the voltage stress across the power switch. So, a low voltage-rated power switch can be used in the presented converter. The suggested topology uses only one power switch with low on-state resistance (RDS-ON), which leads to a simple control circuit and decreases the conduction losses. Highefficiency, operating with low duty cycle, low peak voltage over semiconductor elements, low turns ratio, the number of the coupled inductor, and high voltage conversion ratio are the significant benefits of the recommended DC-DC converter. To show the achievement of the presented structure, operational mode principles, steady-state, efficiency calculations, and comparison results are provided. Finally, a 120 W experimental prototype with 200 V output voltage and 50 kHz switching frequency is built to prove the usefulness of the suggested high step-up converter. The efficiency is measured 92.11% at rated power.

Self-powered autonomous wireless sensor system with multivariable sensing capability

Here we demonstrate a triboelectric nanogenerator (TENG) based fully self-powered multi-parameter wireless sensing system. By integrating the TENG with multiple mutually coupled RLC resonators, the energy harvested by the TENG is directly converted into a decaying oscillating signal containing multiple frequency components with encoded sensing information. The oscillating signals can be transmitted and received by the near-field antennas using inductive coupling and the wireless sensing distance is up to 2 m. A theoretical analysis method based on characteristic parameters is proposed firstly, which is used to obtain the functional expressions between the attenuation coefficients α, eigen frequencies ω and characteristic parameters. Fast Fourier transform (FFT) spectral analysis is used to extract multi-parameters, shows that the theoretical analysis agrees very well with the experimental results. A self-powered wireless strain distribution sensing system based on LabVIEW was developed to demonstrate the feasibility of the proposed multi-parameter sensing technology, the results show that the system can monitor strains and its distribution along a cantilever-like structure precisely, demonstrating its great application potential.

Ultra-High Step-Up Gain Interleaved Coupled Inductor DC–DC Converter with Reduced Voltage Stress and Eliminated Right Half Plane Zero

Ultra-High Step-Up Gain Interleaved Coupled Inductor DC–DC Converter with Reduced Voltage Stress and Eliminated Right Half Plane Zero

Design and fabrication of an interleaved high step‐up DC–DC converter with soft‐switching capability to implement in renewable energy systems

AbstractThis paper presents a soft‐switching non‐isolated interleaved high step‐up topology to implement in renewable energy systems. By using low number of power electronic devices and incorporation with the coupled inductors (CIs) and built‐in transformer (BIT), simultaneously, mixed with a voltage multiplier cell (VMC), an ultra‐large gain can be obtained. In addition, the interlevead structure in the input side causes to diminish the input current ripple. Moreover, the automatic current sharing is another characteristic of the proposed converter. The voltage stresses across power semiconductors are decreased by increasing the turns ratio of the implemented CIs and BIT and also reverse recovery losses are attenuated which improves the efficiency. Furthermore, zero‐current‐switching (ZCS) condition for diodes is achieved at turn off instant, due to the leakage inductances of the magnetic means. Also, power MOSFETs are switched with zero‐voltage‐switching (ZVS) performance by adding active clamp. A 600‐W experimental prototype with 24‐V input to 400‐V output voltage at a switching frequency of 100 kHz is built and tested to examine the merits of the proposed topology

Long-Distance High-Power Wireless Optical Energy Transmission Based on VECSELs

Wireless charging systems are critical for safely and efficiently recharging mobile electronic devices. Current wireless charging technologies involving inductive coupling, magnetic resonance coupling, and microwave transmission are bulky, require complicated systems, expose users to harmful radiation, and have very short energy transmission distances. Herein, we report on a long-distance optical power transmission system by optimizing the external cavity structure of semiconductor lasers for laser charging applications. An ultra-long stable oscillating laser cavity with a transmission distance of 10 m is designed. The optimal laser cavity design is determined by simulating the structural parameters for stable operation, and an improved laser cavity that produces an output of 2.589 W at a transmission distance of 150 cm is fabricated. The peak power attenuation when the transmission distance increases from 50 to 150 cm is only approximately 6.4%, which proves that this wireless power transfer scheme based on a vertical external cavity surface-emitting laser can be used to realize ultra-long-distance power transmission. The proposed wireless energy transmission scheme based on a VECSEL laser is the first of its kind to report a 1.5 m transmission distance output power that exceeds 2.5 W. Compared with other wireless energy transmission technologies, this simple, compact, and safe long-distance wireless laser energy transmission system is more suitable for indoor charging applications.

Efficient Underwater Sensor Data Recovery Method for Real-Time Communication Subsurface Mooring System

Marine submerged buoys can effectively obtain various parameters of seawater, which plays an important role in the research of marine physical phenomena, marine environmental changes, and climate change. However, traditional self-contained submerged buoys usually work underwater at a depth of about 100 m, and the observation data cannot be obtained before their recovery, which cannot satisfy the needs of real-time data acquisition for marine scientific research. To solve this problem, this paper proposes a real-time communication subsurface mooring system that consists of a satellite communication buoy (SCB), conductivity–temperature–depth sensors (CTD), and an inductive coupling mooring cable. The underwater inductive coupling link collects the data from the underwater sensors and transmit it to the SCB. Then, the data will be transmitted to the station receiver via satellite communication module integrated into the SCB. In order to ensure a high success rate of data recovery, the stress analysis and hydrodynamic simulation of the SCB were carried out in this paper. The results show that the SCB maintained a relatively stable attitude in the 3–4 sea state. The attitude data obtained from the subsequent sea trial was consistent with the simulation results, and the success rate of satellite communication during this period was more than 95%. In this paper, a modular embedded hardware circuit was designed to meet the functional requirements of the subsurface mooring system. An efficient data recovery strategy was also developed, which ensured that the average power consumption of the system was low and the success rate of data recovery is not less than 90% when operating in the severe sea state for a long time. The system underwent sea trials in the South China Sea for more than 3 months from the end of 2021 to the beginning of 2022. It transmitted more than 2034 sets of seawater profile temperature, salinity, and depth data in real-time, with a success rate of over 91% of the total sample data. The CTD data returned in real-time from our system is consistent with the data of the HYCOM and World Ocean Atlas (WOA), and a cyclonic mesoscale eddy was detected in the operation area.

Accurate Analytical Models of Armature Reaction Field for Multi-Segment Primaries Ironless PMLSM Based on Subdomain Method

Multi-segment-primary (MSP) ironless Permanent Magnet Linear Synchronous Machine (PMLSM) can be widely applied in long primary, long stroke, and heavy load applications. Therefore, an accurate armature reaction field analysis is very important to control this novel topology motor. In order to simplify the research process, a two-segment-primary (TSP) ironless PMLSM in this article was proposed as the smallest unit. The analytical models of the armature reaction field of the motor based on the subdomain method (SDM) were established considering the finite length of the segment-primary (SP) and the interval distance between the TSP. Then, the coupling effect between the TSP and the end effect of the TSP on the armature reaction field were quantitatively analyzed. Furthermore, the coupling inductance between the TSP can be analytically calculated, which is influenced by the coupling effect. To validate the effectiveness of the proposed models, a prototype of the 24s/28p TSP ironless PMLSM was manufactured and tested. It was shown that the proposed models match well with the simulated and experimental results. As well, the maximum variation rate of the end coupling inductance was about 50.13%.

Dynamics of a dispersively coupled transmon qubit in the presence of a noise source embedded in the control line

We describe transmon qubit dynamics in the presence of noise introduced by an impedance-matched resistor ($50\,\mathrm{\Omega}$) that is embedded in the qubit control line. To obtain the time evolution, we rigorously derive the circuit Hamiltonian of the qubit, readout resonator and resistor by describing the latter as an infinite collection of bosonic modes through the Caldeira-Leggett model. Starting from this Jaynes-Cummings Hamiltonian with inductive coupling to the remote bath comprised of the resistor, we consistently obtain the Lindblad master equation for the qubit and resonator in the dispersive regime. We exploit the underlying symmetries of the master equation to transform the Liouvillian superoperator into a block diagonal matrix. The block diagonalization method reveals that the rate of exponential decoherence of the qubit is well-captured by the slowest decaying eigenmode of a single block of the Liouvillian superoperator, which can be easily computed. The model captures the often used dispersive strong limit approximation of the qubit decoherence rate being linearly proportional to the number of thermal photons in the readout resonator but predicts remarkably better decoherence rates when the dissipation rate of the resonator is increased beyond the dispersive strong regime. Our work provides a full quantitative description of the contribution to the qubit decoherence rate coming from the control line in chips that are currently employed in circuit QED laboratories, and suggests different possible ways to reduce this source of noise.

A high step‐up DC‐DC converter based on coupled inductor and diode‐capacitor with improved voltage gain and efficiency, and reduced voltage stress for photovoltaic systems

AbstractThis paper proposes a nonisolated high step‐up dc‐dc converter, which optimally integrates coupled inductor, and diode‐capacitor and provides superior features such as high gain, high efficiency, and low voltage stresses on power switches. Moreover, the common ground between the input and output of the proposed converter makes it appropriate for photovoltaic systems. It consists of two power switches, one inductor, one coupled inductor (CI), four diodes, and four capacitors. The power switches are exposed to low voltage stresses and are selected from low voltage ratings and low on‐resistance semiconductors. The topology, operating principle, complete steady‐state and ac small‐signal models, loss model, and design criterion are presented and described in detail. Also, the proposed topology is compared with other previous topologies. In order to evaluate the performance of the proposed converter, a 400 V/400 W experimental prototype has been designed and built. Experimental results validate the theory and show the converter produces high gain (14.25 times in the full‐load condition tested) and operates with high efficiency (94.9% in the full‐load condition).

A dual harmonic balanced configuration transformer with harmonic multi-port isolation: Design, modeling and analysis

This paper presents a dual harmonic balanced configuration transformer (DHBCT) carefully designed to achieve harmonic multi-port isolation in the regional hub substation. Firstly, the design and implementation of the special configuration are elaborated. Then, the magnetic field coupling characteristics expressed by the coupling inductances in the dual harmonic balanced configuration are derived and demonstrated. On this basis, the filtering mechanism of the DHBCT that can achieve harmonic multi-port isolation is demonstrated. Besides, in view of the difficulties caused by multiple windings and characterization characteristics for simulation, the electromagnetic decoupling model that can reflect the balanced configuration is established. Considering various application scenarios and the convenience of the application, the decoupling model is extended and simplified. Following that, the fault analysis is investigated using the established model. Finally, the correctness and accuracy of the proposed models and fault analysis method are verified by experiments and simulations.

A High Step-Up Transformerless DC–DC Converter With New Voltage Multiplier Cell Topology and Coupled Inductor

In this article, a new high step-up transformerless dc–dc converter based on a voltage multiplier and a coupled inductor topology is presented. The proposed converter has two stages. In the first stage, a modified boost converter is designed by the coupled inductor, and in the second stage, a new voltage multiplier by using a coupled inductor is illustrated. In this converter, high voltage gain can be achieved by adjusting the turn ratio of two coupled inductors and the duty cycle, which result in three degrees of design freedom. Using a single power switch with low <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small> -resistance in the converter structure leads to simple control and low conduction loss. In addition, total voltage stresses of active elements are decreased, which increases efficiency. Steady-state performance and theoretical achievements are confirmed by experimental test results on a test setup with one 200-W dc–dc prototype.

Synthesis of Dual-Output DC−DC Converters With Coupled Inductor From a Generalized Output Branch

A generalized output branch with coupled inductor is proposed in this article, with which a diversity of single-input dual-output (SIDO) configurations can be synthesized through substituting it for the original inductor in the conventional single-input single-output (SISO) converters. Furthermore, for each configuration, multiple SIDO converters will be generated after realizing the auxiliary voltage source in the generalized output branch with two different nodes. Because the number of magnetic components remains unchanged in comparison with the SISO converter, high power density can be achieved in the derived SIDO converters with coupled inductor. Moreover, the cross-regulation problem is effectively alleviated, and soft-switching operation is realized for switches. Hence, both optimized steady-state and dynamic performance can be obtained. In this article, three example SIDO configurations based on buck, boost, and buck−boost converters are derived, and an example family of 12 SIDO converters from buck converter is demonstrated in detail. Afterwards, a unified operation principle and performance analysis suitable for all these 12 converters are also introduced, which is helpful for the topology comparison. Finally, experimental verification of the theoretical analysis is also conducted.

A Novel Array-Type Symmetrical CI for Multiphase Interleaved DC–DC Converters

For conventional parallel multiphase coupled inductor (CI), it is difficult to achieve full symmetrical coupling. A novel multiphase array CI is proposed, along with the analysis of the relevant symmetry principle, topology combination, and design method. Planar design and exploration are performed, which are then generalized to design a universal <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$n$ </tex-math></inline-formula> -phase symmetrical CI and ring-type array CI with head and tail sequence coupling. The universal design criteria for multiphase symmetrical CI are summarized. Finally, soft switching mechanism is investigated under symmetrical inductance, thereby alleviating the problem of low efficiency at light load. The experimental results prove that the multiphase symmetrical array CI theory is valid and practical.

A High Step-Up Three-Port DC–DC Converter With Reduced Voltage Stress for Hybrid Energy Systems

In this article, a novel three-port dc–dc converter for hybridized energy applications is proposed. The suggested converter's circuit structure applies one coupled inductor (CI) and two CI-based voltage multipliers to increase the voltage gain. The input energy source can supply power to the output load and either charge or discharge the battery. The coupled inductor's leakage inductance is utilized to facilitate zero current switching of all power switches. In addition, by controlling the multiplier diodes' current falling rate, it reduces their reverse recovery losses. Furthermore, all semiconductors' voltage stresses are significantly decreased. The steady-state analyses and considerations for the proposed structure's design are discussed and presented in the various operation states. Also, a closed-loop multi-input-multi-output control method is presented and used to ensure the controllability of the system. Moreover, power management algorithm is defined and applied in the control strategy. Finally, the analysis is supported by experimental results from a 535 W laboratory prototype.

A Bidirectional Active DC Fault Current Limiter Based on Coupled Inductor

When a fault occurs on the dc side of the voltage source converter based high voltage direct current (VSC-HVDC) transmission system, the fault current rises quickly due to the low damping of the dc system. Using a dc fault current limiter (DC-FCL) to limit the rise of the fault current can significantly reduce the breaking requirements of the DCCB. A topology of a bidirectional active dc fault current limiter (BA-FCL) based on coupled inductor is proposed in this paper. No expensive full-controlled power electronic devices are used in this topology. Only a few half-controlled power electronic devices are used to achieve active control of the current limiting unit. Compared with many topologies of current limiter at present, the fault current limiting effect of BA-FCL is improved significantly while the cost, volume, topology complexity, and control complexity are reduced. The stress analysis and parameter design of the proposed current limiter are carried out. Finally, the simulation case study and hardware experiment are implemented to verify the good economy and current limiting performance of the proposed topology.

Analysis and Design of Efficient Interleaved Bidirectional Converter With Winding Cross Coupled Inductors

This article presents a nonisolated bidirectional converter (BDC) with high voltage conversion ratio. The structure of winding-cross-coupled-inductors (WCCIs) is developed in the two-phase interleaved BDC to achieve the excellent features of current-ripple-cancellation, current sharing, and high voltage-gain. Furthermore, the proposed topology uses two active and passive clamp circuits to recover the coupled inductors’ leakage energy and to maintain the overall efficiency at a high level providing zero voltage switching (ZVS) in boost mode. A rearrangement is applied to high-voltage-side switches to avoid the interference of clamp circuits operation in boost and buck modes. Detailed analysis and design methodology of the proposed converter are provided and a high gain 500 W, 48 V/380 V prototype is implemented to verify the performance of the proposed converter. Peak efficiencies of 96% and 94.3% are measured for boost and buck modes, respectively.

Generalized Theory of PT-Symmetric Radio-Frequency Systems With Divergent Exceptional Points

The emergence of exceptional point (EP) and its divergent form, so-called divergent EP (DEP), in parity-time (PT)-symmetric trimer opens a new pathway for making radio frequency (RF) telemetric sensor systems with unprecedented sensitivity. Here, we put forward a rigorous and formally exact analysis for PT -symmetric electronic multimers, shedding light on the lower bound of the inductive coupling coefficient required to achieve DEPs. One clear observation is that there exists a subtle compromise among the degree of diverging bifurcation, critical inductive coupling strength, and spectral noises arising from modal interferences. We conclude that an electronic PT -symmetric trimer, although not sufficient to work at the lowest inductive coupling strength, may be the simplest structure that enables the emergence of DEPs. Our findings may provide the theoretical underpinnings and open avenues for various RF telemetry and wireless sensing systems.

Single terminal and double terminal coil shape analysis using capacitive power transmission for biomedical implant

• Miniaturized antenna for longer distance and power transfer for bioelectronics. • Wireless power technology with lower heating rising to power bioelectronics. • Use single transmitter antenna to generate capacitive and inductive coupling. • Inductive and capacitive antenna configuration comparison in heating, distance and power transfer. This paper proposed a transmitter antenna using single terminal coil shape design and receiver antenna using double terminal coil shape design (Cs-Cd) to enhance the electric and magnetic coupling for Capacitive Power Transfer system to achieve higher energy transmission. This method used only single transmitter antenna instead of two transmitter antennas for power transmission. This design configuration was compared with other four configurations using either capacitive power transfer or inductive power transfer. As a result, Cs-Cd configuration achieved higher receiving power at longer implantation distance and lower temperature heating compared to conventional inductive power configuration. This method showed a better approach to power wirelessly miniaturized implant medical device.