Tank Circuit Research Articles

Interview

Marco Bau Doctor Marco Bau from the University of Brescia in Italy, talks to Electronics Letters about the paper ‘Magnet-less electromagnetic contactless interrogation technique for unwired conductive resonators’, page 642. Our research group in the Department of Information Engineering operates in the fields of sensors, microsystems, electronics and measuring instrumentation. One of our topics of research is the investigation into the possibility of interrogating sensors without contact by means of an external unit which can be placed in the proximity of the sensor, a few centimetres away. In addition, we focus our efforts on using completely passive sensors, that is devices which do not have on-board active electronics or a power supply. Typically, these devices are mechanical or electromechanical resonating structures vibrating at their own resonant frequency and this frequency can change due to specific physical/chemical quantities. Our work investigates techniques to excite and sense the vibrations of such structures without any physical contact and, at the same time, challenging issues due to unfavourable signal-to-noise ratio. Sensors which can be interrogated without contact with an external unit are attractive for applications in environments and locations that are difficult to access and do not allow for cabled solutions, such as measurements inside sealed packages, enclosures and rotating parts, or even the human body. In these contexts, battery-powered systems are one possible solution, but they demand active electronics and energy sources be located on both the sensing device and the interrogation unit. Here, the main drawback is the necessity for periodical recharge/replacement of the sensor battery. As an alternative, the sensor and associated circuitry can be battery-less and powered by energy transfer from the reader, or by harvesting energy from the environment. But again, active electronics are required. However, sometimes this is not compliant with the application, such as for operation in high-temperature environments, where active electronics are not feasible. In our work we have adopted mechanical resonator structures which are only required to be electrically conductive. The excitation and detection of the vibrations exploit an electromagnetic principle, based on the induction of eddy currents on the surface of the resonator through a dedicated proximate 3-coil arrangement. Using only AC magnetic fields to generate vibrations in the resonator gives rise to non-linear behaviour, that is the mechanical structure vibrates at twice the frequency of the exciting magnetic field. In the phase of detection, this may require sophisticated electronic circuits and techniques. Alternatively, it is possible to use both DC and AC magnetic fields, so that excitation and vibration of the structure result in the same frequency. DC magnetic fields are typically generated by magnets, which in some circumstances can be impractical. In our work, magnets are avoided by exploiting a purposely designed 3-coil arrangement to generate both DC and AC magnetic fields. Our approach is particularly advantageous as, in addition to avoiding poling magnets, it allows the detection of vibrations through the same coil arrangement used for excitation. Indeed, we generate an additional AC probing magnetic field, which does not affect the excitation of the resonator, but is modulated by its movement. We detect the vibration-modulated magnetic field adopting a differential measurement technique which allows for an improvement to the signal-to-noise ratio. We expect that the results we have reported will be the starting point to improving the technique and exploring the limits of where it can be pushed in terms of downscaling of the sensing devices, possibly comprising also MEMS devices. We are confident that the proposed technique can be tested in selected practical applications for which we have received interest from industrial partners. Our focus is to further investigate different possibilities for contactless interrogation sensors limited not only to eddy-current based principles. Indeed, we have proposed, and are investigating, techniques still based on electromagnetic coupling, which extend the possibility of contactless interrogation to other typologies of resonating devices, like quartz crystal resonators (QCR), piezoelectric resonators, MEMS electromechanical resonators or electrical resonators based on inductor-capacitance tank circuits. In all these cases, we aim to adopt measurement techniques which can achieve accurate resonant-frequency readouts independent of the reading distance. The advantages and opportunities afforded by contactless interrogation techniques have been investigated in depth in recent years. We think that research in this field will be pursued extensively in the future with the aim of obtaining devices which will be energy-independent, environment-friendly, unobtrusive, disposable and can be interrogated on-demand and as needed. Maybe interrogating devices will be integrated in portable devices (such as smartphones) and will make this technology available for both industrial applications and every-day life.

Modelling of a converging/diverging tube using CATHARE-3 two-phase flow system code for sodium cavitation studies

For reactor design and safety purposes, the French Alternative Energies and Atomic Energy Commission (CEA) is currently working on Sodium Fast Reactor (SFR) thermal-hydraulics. A SFR is a system composed of three circuits (primary and secondary: liquid sodium and tertiary: nitrogen gas or water) and designed to both produce electricity and optimize nuclear fuel cycle. In such SFR systems, primary pumps are associated as a parallel circuit. Then, throughout primary pump seizure transients, cavitation may occur in non-affected pumps because of the induced hydraulic resistance drop. Studying sodium flow cavitation occurring in simple geometries such as a Venturi tube (converging/diverging tube) is the first step to better understand the phenomenon and its sensitivities. The long term aim is to validate the flashing model used for sodium applications in the CATHARE-3 code in order to be confident when simulating more complex geometries. In this article, a Venturi tube test section experimented in the CANADER facility at CEA Cadarache in the 1980s and its modelling are presented. Cavitation is obtained by flow rate variation at fixed tank pressure and circuit temperature conditions. Several computations are made in order to study the sensitivity of results to numerical and physical parameters. A set of parameters supposed to constitute the most representative case is defined and comparison of the predicted Thoma number against the experimental one is made. Detailed results of quantities of interest as profiles along the test section and evolutions during the transient are also presented.

Full-bridge LLC Resonant High-voltage DC–DC Converter with Hybrid Symmetrical Voltage Multiplier

This article presents an LLC resonant high-voltage DC–DC converter based on the hybrid symmetrical voltage multiplier that consists of the full-bridge inverter circuit, one resonant tank circuit, one power transformer, and the voltage multiplier circuit. The proposed converter operates below resonance on the negative slope region of DC characteristics curve for realization of zero voltage switching (ZVS) operation. Within this operating region, the power switches and output diodes of the converters generally operate under the ZVS and zero current switching (ZCS) conditions, respectively. The detail structure, design procedure, operation, and steady-state analysis of the proposed converter are thus described. Furthermore, an experimental prototype was built and tested with the input voltage of 100VDC. The results show that the proposed converter is capable to operate under soft-switching conditions, resulting in higher efficiency. The maximum efficiency of the proposed converter of about 96% was recorded at the output power of 550 W.

A low phase noise quadrature VCO using superharmonic injection, current reuse, and negative resistance techniques in CMOS technology

In this article, a low phase noise quadrature VCO (QVCO) is proposed, which uses superharmonic injection and current reuse techniques to reduce phase-noise and power consumption. The LC tank circuit quality factor is improved, using a negative resistance. PMOS transistors have also been used instead of NMOS transistors. As a result of these modifications, further phase noise reduction is achieved. The QVCO consists of a VCO operating at 2ω0 (twice the operating frequency) injecting its output signal into the common source nodes of two other oscillators operating at ω0. Using this superharmonic injection technique, in addition to phase noise reduction, the chance of injection pulling caused by powerful PA signals is reduced. Also, the current reuse technique automatically adapts its voltage to the requirement of the supplied stages, therefore, it is not limiting the VCO output swing. Designed for the 900 MHz band and simulated in a 0.18 µm CMOS technology with 1.8 V power supply, the circuit achieves a phase noise of − 141.5 dBc/Hz at 1 MHz offset frequency, while consuming 12.8 mW power. The proposed circuit is compared with several re-simulated previously published work. The comparison shows 17.5 dB reduction in phase noise compared to conventional P-QVCO, while consuming the same amount of power.

Comparative study on influence of energy transmission characteristics of transmission coil consist of resonant tank circuit topologies suitable for wireless power transmission system

Comparative study on influence of energy transmission characteristics of transmission coil consist of resonant tank circuit topologies suitable for wireless power transmission system

Study on a power transmission characteristics of wireless power transmission system by using the novel coil structure with auxiliary resonant tank circuit

Study on a power transmission characteristics of wireless power transmission system by using the novel coil structure with auxiliary resonant tank circuit

On boundary analysis for derivative of driving point impedance functions and its circuit applications

In this study, a boundary analysis is carried out for the derivative of driving point impedance (DPI) functions, which is mainly used for the synthesis of networks containing resistor-inductor, resistor–capacitor and resistor–inductor–capacitor circuits. It is known that DPI function, Z ( s ) , is an analytic function defined on the right half of the s-plane. In this study, the authors present four theorems using the modulus of the derivative of DPI function, | Z ′ ( 0 ) | , by assuming the Z ( s ) function is also analytic at the boundary point s = 0 on the imaginary axis and finally, the sharpness of the inequalities obtained in the presented theorems are proved. It is also shown that simple inductor–capacitor tank circuits and higher-order filters are synthesised using the unique DPI functions obtained in each theorem.

Compact D-CRLH resonator for low-pass filter with wide rejection band, high roll-off, and transmission zeros

AbstractA compact low-pass filter (LPF) with wide rejection band based on T-type circuit of an enhanced dual composite right-/left-handed (D-CRLH) resonator is presented in this paper. The resonator has only one cell with series and parallel tank circuit. The parallel LC tank circuit has been realized by an interdigital capacitor and one shorted finger, whereas its series LC tank circuit is realized by an air gap capacitance and a short circuit stub. The filter has wide rejection band bandwidth with three transmission zeros (TZs). The filter bandwidth and TZs frequencies are controlled by the D-CRLH element values. The results of the proposed filter demonstrate minimum insertion loss in passband, high roll-off rate, and good figure of merit. The measured results are in good agreement with the simulated results. The detailed filter design is discussed in terms of circuit modeling, dispersion analysis, and full-wave simulation. Finally, the filter size is compact (0.10 λg × 0.15 λg) at cut-off frequency.

Equivalent circuit and numerical analyses of an inductively coupled plasma torch with a tapped induction coil

Equivalent circuit and numerical analyses of an Ar-N2 inductively coupled plasma (ICP) were conducted in order to clarify the effect of the induction coil with a grounded tap on the electrical characteristics of an ICP torch system. First, from the computational results, it was revealed that the load resistance of tank circuit for a free running radio-frequency (RF) oscillator can be reduced to about 25% with a center-tap of the induction coil grounded. Despite the asymmetric distributions of the electric fields in the inside of the ICP torch, this effect was found due to the equivalent resistance and inductance of ICP that were divided in approximately half into each part of the center-tapped induction coil. The reduction of the load resistance by a grounded tap was also observed in generation experiments of Ar-N2 ICPs using a vacuum tube oscillator for various N2 contents ranging from 6.3 % to 25.0 %. By providing a way to reduce the load resistance of the tank circuit, the induction coil with a grounded tap can be used to improve the impedance matching condition of ICP systems with the load resistances higher than the internal resistance of a free running RF oscillator.

Efficient Activation of Nanomechanical Resonators

AbstractElectrostatically transduced nano‐electromechanical system resonators operating in the very high and ultra‐high frequency bands are promising for many practical applications. However, electrostatically transduced nanoscale devices commonly suffer from poor transduction efficiency due to the reduced capacitive area for actuation and detection. Also, the requirement of ultra‐high actuation forces renders exploitation of their higher‐order vibration modes and the desirable nonlinear behaviors practically beyond reach. Hence, it is imperative to develop a methodology that efficiently actuates nano and sub‐micrometer scale highly stiff resonators with low voltages available in a standard integrated circuit. Here, the utilization of the passive voltage amplification across the inductor of an inductor–capacitor LC tank resonant circuit to efficiently actuate nanoresonators with high forcing amplitude is proposed and demonstrated. The proposed technique is simple and flexible in its implementation, and does not require any active electronic components. A forcing amplification up to 19 times (≈25 dB) is experimentally shown, which can be improved further by reducing the electrical damping in the tank circuit. In addition, two independent ports on the same device for force amplification are shown, which, if simultaneously activated, can increase the overall forcing amplitude by an order of magnitude exceeding hundreds of amplification gain.

Active-Controlled Passive Distribution of Power Offers Efficient Heat Treating Solution for Quality Arc Welding Joints of Steel Pipes

Using high energy density welding arc, the joining process makes pipe joints involving melting of base metal. The thermal cycle could cause distortion and have residual stress around joints and there could be a prospect of hydrogen cracking. By employing proper heat treatment procedures, the physical, metallurgical, and mechanical properties of steel structures are regained for their long endurance under extreme operating conditions of pressure and temperature, particularly, in power industries. The joints need to undergo pre- and post-weld heat treatment. Induction heating is increasingly being used for heat treatment of pipes, tubes, pressure vessels, etc., made up of a special type of steel such as P91 Grade. As the popularity of the heat treatment process is on the rise, it is important to look into the energy efficiency and power delivery aspects of the system. This paper proposes an innovative method to configure the induction heating controller and the tank circuit so that the energy delivery to the pipe and its usage are inherently improved. The proposed ideas have been practically demonstrated using a 40–45 kW induction heater.

Efficiency Improvement for a DC-DC Quadratic Power Boost Converter by Applying a Switch Turn-off Lossless Snubber Structure Based on Zero Voltage Switching

So as to keep the converter in small size, high switching frequencies are normally used. As a result, in higher frequencies, switching losses seriously affect the efficiency. Current and voltage stresses on power switch can be serious problems particularly in high amount of powers where MOSFET switches are generally applied. A snubber circuit can reduce or eliminate spike voltage and currents, decrease the di/dt or dv/dt values on power switch and transfer the power losses on switch to load and increases the lifelong of the switch. This study presents a method for improving the power transmission efficiency for DC-DC Cascaded Boost Converter and uses a passive snubber sub-circuit, which consists of an inductor, a capacitor, and two diodes for reducing the switching loss. The role of resonant capacitor of this structure is discharging directly through the load and is parallel with the power switch. Thus, it is effective in lossless switching and increasing the DC voltage gain of the boost converter. Soft switching is achieved through the use of a LC resonant tank circuit. The tank circuit is responsible for zero voltage switching (ZVS) and zero current switching (ZCS), eliminating the power loss in the switches appreciably. The proposed structure, done by MATLAB SIMULINK based on simulations, has shown more efficiency toward the same structure without snubber circuit. Besides, an application has been conducted in laboratory scales, and results confirm theoretical findings.DOI: http://dx.doi.org/10.5755/j01.eie.24.3.20977

Resonances and Phase Locking in Josephson High-Q Circuit

We consider Josephson junction coupled to a high-quality tank circuit and present both analytic analyses and numerical simulation results for resonances of both force and parametric types as well as Shapiro steps under microwave irradiation with frequency close to the resonance one. Physical mechanisms of the phenomena are studied and discussed.

A 2.4 GHz Low Power Low Phase-Noise Enhanced FOM VCO for RF Applications Using 180 nm CMOS Technology

The Voltage Controlled Oscillator (VCO) is an important component of the transceiver which consumes significant energy as compared to the other transceiver components. Since RF application systems such as WiFi, Bluetooth or Zigbee uses battery energy, it is necessary to reduce the power consumption while maintaining reasonable system performance. In this work, the performance of standard VCOs is studied and a new design method of CMOS VCO is proposed. The architecture of the proposed VCO is based on the negative resistance based LC tank circuit using MOSFET. The performance of the proposed VCO is compared in terms of phase noise, figure-of-merit (FOM) and power consumption. The phase noise and FOM of the proposed design is ýý124 and ýý187.25 dBc/Hz respectively at 1 MHz offset frequency with power consumption of 2.86 mW. It has been observed that the proposed VCO can be a suitable candidate for low power RF circuit applications while maintaining reasonable performance metrics.

Numerical Analysis on the Electrical and Thermal Flow Characteristics of Ar-N2 Inductively Coupled Plasma Torch System

Numerical analysis on the electrical and thermal flow characteristics of Ar-N2 inductively coupled plasma (ICP) were carried out for N2 content from 0 to 50 mol% at plasma power level of 50 kW. Firstly, the computational results of thermal flow fields revealed that the addition of N2 could reduce the radiation heat loss, together with increasing the exit enthalpy. For example, the radiation heat loss of Ar-N2 ICP with N2 content of 20 mol% is reduced by ∼ 33%, compared with that of Ar-only ICP, which are essential for the safe operation of an ICP system at the high power level of 50 kW. In addition, the increase of N2 content was also found to increase the load resistance of a tank circuit for a vacuum tube oscillator. Equivalent circuit analysis using the numerical results shows that this increase of the load resistance comes from the increasing equivalent resistance and the decreasing equivalent inductance of Ar-N2 ICP, corresponding to the changes of thermal flow fields with the increase of N2 content. For a tank circuit consisting of a capacitor and an inductor with a capacitance of 6,500 pF, and an equivalent inductance of 0.84 μH, the load resistance was calculated to be increased from 81 Ω for Ar only ICP to 130 Ω for Ar-N2 ICP with N2 content of 20 mol%. Considering the internal resistances of high power vacuum tubes higher than 130 Ω, this increase of load resistance clearly shows that N2 addition can improve the impedance mismatching of an ICP torch system with a vacuum tube oscillator having no variable part to tune the load resistance. By providing these basic data for the calculation of load resistance and thermal flow characteristics, the numerical analysis combined with equivalent circuit analysis used in this work can help in designing and operating a high-powered ICP torch system with a vacuum tube oscillator.

Note: Commercial SQUID magnetometer-compatible NMR probe and its application for studying a quantum magnet.

We present a compact nuclear magnetic resonance (NMR) probe which is compatible with a magnet of a commercial superconducting quantum interference device magnetometer and demonstrate its application to the study of a quantum magnet. We employ trimmer chip capacitors to construct an NMR tank circuit for low temperature measurements. Using a magnetic insulator MoOPO4 with S = 1/2 (Mo5+) as an example, we show that the T-dependence of the circuit is weak enough to allow the ligand-ion NMR study of magnetic systems. Our 31P NMR results are compatible with previous bulk susceptibility and neutron scattering experiments and furthermore reveal unconventional spin dynamics.

Auto synchronous bandpass filter based on indium-doped CdS

Samples were grown on glass substrates of CdS doped with different levels of indium via the chemical bath technique. The samples obtained were optically characterized to determine their band-gap. A capacitor of parallel plates is constructed with the CdS samples placed between the plates; afterward, light with energy above the band-gap is used to generate carriers in the CdS to modify its dielectric properties and therefore the capacitance. The sample that causes greater current through the capacitor is used to form part of the tank circuit of a bandpass filter because this tank circuit determines the frequency of resonance or passage of the filter, thus forming a bandpass filter whose resonance frequency depends on the intensity of light that impinges on the CdS sample. Finally, the frequency responses of the filter when the sample is not illuminated compared to that when it is illuminated are studied to demonstrate a filter whose resonance frequency can be effectively controlled by light via the use of indium-doped CdS.

Insights into Dynamic Tuning of Magnetic-Resonant Wireless Power Transfer Receivers Based on Switch-Mode Gyrators

Magnetic-resonant wireless power transfer (WPT) has become a reliable contactless source of power for a wide range of applications. WPT spans different power levels ranging from low-power implantable devices up to high-power electric vehicles (EV) battery charging. The transmission range and efficiency of WPT have been reasonably enhanced by resonating the transmitter and receiver coils at a common frequency. Nevertheless, matching between resonance in the transmitter and receiver is quite cumbersome, particularly in single-transmitter multi-receiver systems. The resonance frequency in transmitter and receiver tank circuits has to be perfectly matched, otherwise power transfer capability is greatly degraded. This paper discusses the mistuning effect of parallel-compensated receivers, and thereof a novel dynamic frequency tuning method and related circuit topology and control is proposed and characterized in the system application. The proposed method is based on the concept of switch-mode gyrator emulating variable lossless inductors oriented to enable self-tunability in WPT receivers.

Analysis and Performance Evaluation of Control Methods for LLC Resonant Converter

An LLC resonant dc to dc converter in the company of an LC ant resonant tank circuit for civilizing the act of pulse frequency modulation (PFM) is projected in this manuscript. The planned converter, known as LLC-LC converter, can expand a voltage guideline area below the unity gain with a lesser frequency variation of Pulse frequency modulation by the effect of the antiresonant tank. This beneficial possessions contribute for shielding over current in the case of the short-circuit load condition as well as the bring into being interval in the planned band of switching frequency. The circuit topology and working theory of the planned converter is described, subsequent to the design method of the working frequency and circuit parameters are offered. The performance of the soft switch and the steady-state pulse frequency modulation distinctiveness of the LLC-LC converter are evaluated underneath the open-loop control in conduct experiment of a 2.0-kiloWatts trial product, and its real effectiveness is compared with an LLC converter model. Intended for enlightening the usefulness of the LLC-LC resonant circuit, voltages and currents of the series and ant resonant tanks are analyzed, correspondingly, with state-plane trajectory based on computation and experimentation, where by the power and energy of resonant tank is verified. To conclude, the possibility of the projected converter is evaluate from the realistic point of vision.

Josephson Thermal Memory

We propose a superconducting thermal memory device that exploits the thermal hysteresis in a flux-controlled, temperature-biased superconducting quantum-interference device (SQUID). This system reveals a flux-controllable temperature bistability, which can be used to define two well-distinguishable thermal logic states. We discuss a suitable writing-reading procedure for these memory states. The time of the memory writing operation is expected to be on the order of ~0.2 ns, for a Nb-based SQUID in thermal contact with a phonon bath at 4:2 K. We suggest a non-invasive readout scheme for the memory states based on the measurement of the effective resonance frequency of a tank circuit inductively coupled to the SQUID. The proposed device paves the way for a practical implementation of thermal logic and computation. The advantage of this proposal is that it represents also an example of harvesting thermal energy in superconducting circuits.