Additional Resistor Research Articles

Passive damping of several resonances using multi-branch resonant piezoelectric shunts

Vibration damping using resonant piezoelectric shunts is a method to reduce the amplitude of mechanical resonances by coupling an electrical circuit to a structure through a piezoelectric transducer. The shunt consists of an inductor which creates a resonator tuned to the frequency of the mode to be controlled. In order to damp several resonances simultaneously, multi-branch shunts can be used. Multiple electrical lines are then connected to a single piezoelectric patch. In this work, focused on purely passive control, a circuit involving resistors in series with the inductors is considered. Indeed, each wire wound inductor is usually associated with a non-negligible series resistance due to copper losses. Several multi-branch shunt architectures have been proposed in the literature. From a selection based on their feasibility in passive control, two solutions are retained: the Hollkamp shunt and the current blocking shunt. After numerical implementation, the two architectures are compared, notably by evaluating the effect of the inductance variations with respect to their nominal values and highlighting the influence of additional resistors.

Solving dynamic electric circuit with nonlinear hysteretic inductor using harmonics interpolation method

SummaryThe aim of this paper is to present a methodology for solving а dynamic electric circuit with nonlinear hysteretic inductor without the use of hysteresis model or equivalent circuits. A consideration of nonlinear and hysteretic behaviour of the magnetic core under quasistatic conditions is based on applying harmonics interpolation method (HIM) to the measured magnetising field strength waveforms. A dynamic behaviour of the magnetic core is considered through the application of the statistical theory of losses (STL). A considered electric circuit consists of AC voltage source connected in series with shunt resistor, additional linear resistor and inductor, as well as a nonlinear hysteretic inductor. The solution for electric current of the circuit is obtained by solving equation derived from Kirchhoff's laws through a series of successive iterations. Coupling of electric and magnetic part of the circuit is obtained from fundamental laws of electromagnetism. Methodology is validated for four cases of the considered electric circuit — without additional elements, with one additional or both additional elements, for sinusoidal voltage source amplitudes of 2, 4, 6, 8 and 9 V and frequency of 50 Hz. Validation is repeated for frequencies of 100, 200 and 300 Hz while keeping the ratio of the amplitude to frequency constant. Detailed theoretical approach and methodology, comparisons between measured and calculated results, as well as adequate discussion are presented.

Розробка цифрового інтерфейсу для керування імпульсним блоком живлення

Most switching power supplies are not designed to change their output voltage. However, situations arise where a different voltage from the power source is needed. The purpose of this article is to develop a practical interface scheme for digitally controlling the output voltage of a switching power supply with an analog feedback loop. The article presents the results of the research of isolated flyback switch-mode power supply (SMPS) circuits, determines the method of controlling the output voltage of the SMPS, and proposes a digital interface for controlling the output voltage of the power supply. The emphasis was on using readily available, inexpensive components with minimal modification to the existing design. The study revealed limitations in existing switching power supply designs regarding effective output voltage control. Modifying the internal reference source is often not an available option. Therefore, influencing the feedback circuit emerges as a simple and viable control method. All power supply feedback loops include a voltage divider measuring the output voltage of switching power supply. This research demonstrates that controlling output voltage can be achieved by injecting or draining current within or from output voltage divider of power supply. Draining current increases the output voltage, while injecting decreases it. The additional resistor only requires a single connection point within the existing circuit. The proposed method provides a linear dependence of the output voltage increase on the value of the injected/drained current. It is shown that the digital interface scheme depends on the number of discrete levels of the required output voltage. For a small number of levels, field-effect transistors controlled by a positional or binary code can be used to control the power supply, and with a significant number of levels, it is advisable to use ready-made digital-to-analog converters.

Assessing Local Electrical Properties of Ionic Liquid/Metal Interfaces with Operando-XPS and by Incorporating Additional Circuit Elements.

X-ray photoelectron spectroscopy (XPS) has been utilized to record binding energy changes upon applying direct current (DC) and/or alternating current (AC) (square-wave) bias with different frequencies on a coplanar capacitor, having an ionic liquid (IL) film as the electrolyte. Electrical potential developments in numerous locations on the device are extracted from the variations in binding energy positions of the atomic core levels, which together with electrochemical measurements are used to extract local information before and after insertion of additional resistors in series. The presence of the IL introduces complex charging/discharging processes with a direct influence on the electrical double layer (EDL) formation, some of which can be untangled from each other via AC modulation by choosing appropriate time windows of observation. Accordingly, under 10 kHz modulation, fast processes are sampled, which are associated with electronic currents, and effects of slow migratory currents can be measured using 0.1 Hz. The addition of serial resistors allows us to quantify AC currents passing through, which reveals the magnitude of the system's impedance under different conditions. This process surprisingly reverses differences(s) in the voltage developments between the low and high frequencies over the electrified electrodes compared to those over the porous membrane in between. Our approach turns XPS into a powerful electrical and surface-sensitive tool for extracting localized electrochemical properties in a noninvasive and direct way. We expect that a wider utilization of the technique will lead to better identification of the obstacles for developing the next-generation sensing, energy harvesting, and storage systems as well as devices for iontronic/neuromorphic applications.

A convenient switch design for high time resolution and energy resolution in ion velocity imaging

Time-sliced velocity map imaging (VMI) has extensively been applied in photodissociation dynamics studies, thanks to its unique advantages, such as high energy resolution and no requirement of inverse Abel or Hankel transformations. However, its time resolution is generally insufficient for distinguishing adjacent m/z ions with a certain kinetic energy due to the overlapping of time-of-flight distributions. Herein, we have made a novel and convenient switch design for the common ion optics in three-dimensional (3D) VMI. By simply introducing two additional resistors out of the vacuum chamber, the strength ratio of the extraction and acceleration fields is easily changed from 3D VMI to two-dimensional (2D) VMI under optimized conditions, as well as a significant extension of free drift length, leading to a higher time resolution while maintaining the high energy resolution. As a result, 2D and 3D VMI can be quickly switched without breaking the vacuum and replacing the electrostatic plates.

OPTIMIZATION OF STARTING MODES OF A SYNCHRONOUS MOTOR WITH MULTISTAGE COMPENSATION OF THE INERTIA EXCITATION CIRCUIT

The work solves an actual scientific problem, which consists in increasing the starting moment of a synchronous motor for reversing mechanisms with a significant moment of static resistance according to the simultaneous limitation of stator currents due to the use of a thyristor voltage regulator with the use of multi-stage compensation of the inertia excitation circuit. The problem of starting a powerful synchronous motor with current limitation does not lose its relevance, primarily for reversing mechanisms with a significant moment of static resistance, as well as in the conditions of powering the motors from long electrical networks, which is typical for drives of mechanisms of drilling rigs in the oil and gas industry, turbocompressors of gas pumping stations and quarry excavators.To evaluate the effect of the developed device on the start of a synchronous motor in the conditions of limiting the voltage of the power supply network with the help of a regulator, the calculated dependences of the motor start-up with a step change in the storage capacity depending on the slip are given.The static dependence of sliding on the moment M is presented, and the stator current is presented. The dynamic characteristics of the engine start using the proposed system and the direct asynchronous start with a tenfold additional resistor are presented.The use of the developed device made it possible to increase the electromagnetic moment developed by the engine from twice to 2.5 times the nominal one. As a result of the redistribution current load between the rotor circuits, the current in the damper winding at start-up decreased by an average of one rating in the longitudinal and transverse windings.

Design and analysis for the SPICE parameters of waveform-selective metasurfaces varying with the incident pulse width at a constant oscillation frequency

In this study, we numerically demonstrate how the response of recently reported circuit-based metasurfaces is characterized by their circuit parameters. These metasurfaces, which include a set of four diodes as a full wave rectifier, are capable of sensing different waves even at the same frequency in response to the incident waveform, or more specifically the pulse width. This study reveals the relationship between the electromagnetic response of such waveform-selective metasurfaces and the SPICE parameters of the diodes used. In particular, we draw conclusions about how the SPICE parameters are related to (1) the high-frequency operation, (2) input power requirement and (3) dynamic range of waveform-selective metasurfaces with supporting simulation results. First, we show that reducing a parasitic capacitive component of the diodes is important for realization of the waveform-selective metasurfaces in a higher frequency regime. Second, we report that the operating power level is closely related to the saturation current and the breakdown voltage of the diodes. Moreover, the operating power range is found to be broadened by introducing an additional resistor into the inside of the diode bridge. Our study is expected to provide design guidelines for circuit-based waveform-selective metasurfaces to select/fabricate optimal diodes and enhance the waveform-selective performance at the target frequency and power level. Our results are usefully exploited to ensure the selectivity based on the pulse duration of the incident wave in a range of potential applications including electromagnetic interference, wireless power transfer, antenna design, wireless communications, and sensing.

Motor driving force of bridge-type crane lifting mechanism under real operating use

Introduction. The requirement for modelling the dynamic processes of a hoisting mechanism in real operating situations has been revealed. The necessity of increasing the accuracy of moving effort description for the most common types of crane hoist drive control has been determined.Materials and Methods. The operation of a single-speed electric motor with squirrel-cage rotor without speed control, with a phase rotor and additional resistors in the rotor winding and with a squirrel-cage rotor and control by a frequency converter has been considered. The static characteristic of the electric motor is taken as the initial function. The Clauss formula with the corresponding values of the parameters synchronous speed, critical force and critical slip was used to take into account the driving force of the motor for frequency control and for relay-contactor control and a motor with a phase-rotor and additional resistances in the rotor circuit.Results. The dependences for the motor driving force with the most common methods of speed control of the crane hoisting mechanism drive are presented. In the case of the frequency control system, the form of the motor driving force is given in the case of steady-state motion and in the case of transient starting/braking processes when the corresponding algorithms are implemented by a frequency converter. Experimental and theoretical graphs of the load lifting processes for the cases of lifting with pickup in the relay-contactor control system and with elastic pickup in the frequency control system are given.Conclusion. The conclusion about applicability of static mechanical characteristic for description of electric motor operation in crane drives is given. The presented dependences provide an opportunity to model the full working cycle of the hoisting mechanism. The dependences are valid both during steady motion of the mechanism and during transients. It is concluded about the use of the dynamic model taking into account the presented form of the motor driving force for practical purposes for the analysis of the crane operation with regard to the effect of the lifting capacity limiter.

A Novel Filter With High Harmonics Attenuation and Small Dimension for Grid-Connected Inverter

Passive power filters are indispensable for grid-connected inverters (GCIs) to eliminate current harmonics. However, typical filters require large inductance, which not only increases the filter dimension and costs but also leads to slower current response and a high voltage drop across the filter. This article proposes a novel filter called LCTCL filter, which effectively attenuates harmonics with small inductance. In addition, this article presents a controller synthesis to the GCI with LCTCL filter without an additional resistor. We demonstrate the effectiveness of the proposed LCTCL filter through comparative analysis with typical filters via simulations and experiments. We clarify that the proposed LCTCL filter has excellent features in terms of filter dimension, frequency characteristics, robustness for parameter variations, harmonic suppression, and total harmonic distortion.

A Comparison of the Use of Pontryagin’s Maximum Principle and Reinforcement Learning Techniques for the Optimal Charging of Lithium-Ion Batteries

Battery systems are one of the most important components for the development of flexible energy storage for future applications. These comprise energy storage in both the mobility sector and stationary applications. To ensure the safe operation of multiple battery cells connected in series and parallel in a battery pack, it is essential to implement state of charge (SOC) equalization strategies. Generally, two fundamentally different approaches can be distinguished. On the one hand, these are passive approaches for SOC equalization that are based on including additional Ohmic resistors in a battery back over which equalization currents flow as long as the correspondingly connected cells have different voltages. Despite the simple implementation of such equalization circuits, they have a major drawback, namely wasting stored energy to perform the SOC equalization. This waste of energy goes along with Ohmic heat production, which leads to the necessity of additional cooling for batteries with large power densities. On the other hand, active SOC equalization approaches have been investigated, which allow for an independent charging of the individual cells. Especially, this latter approach has big potential to be more energy efficient. In addition, the potential for a reduction of Ohmic heat production may contribute to extending the lifetime of battery cells. To perform the individual charging of battery cells in an energetically optimal manner, this paper provides a comparison of closed-form optimization approaches on the basis of Pontryagin’s maximum principle and approaches for reinforcement learning. Especially, their accuracy and applicability for the implementation of optimal online cell charging strategies are investigated.

3-레그형 2상 인버터에서의 전류 복원 영역 확장

For measuring phase currents of two-phase motors driven by the three-leg inverters, the leg shunt resistors inserted between the lower switch of each inverter leg and the negative DC rail can be used instead of the expensive Hall-effect sensors. The two-leg shunt method using shunt resistors located on the two-phase legs has a limited current measurement range. In addition to this method, the three-leg shunt method can reconstruct the immeasurable phase currents by using an additional shunt resistor on a neutral leg. Therefore, the current measurement range can be wider than that in the two-leg shunt method. However, this method cannot properly reconstruct the currents in the specific areas where the voltage modulation index of the inverter is high, thereby decreasing the DC voltage utilization rate, and increasing the torque ripple of the motors. To improve this problem, this paper analyzed the current reconstruction areas of a three-leg type two-phase inverter applied CPWM(Continuous Pulse Width Modulation) method, and proposed a simple technique to expand the areas. The proposed technique can expand the current reconstruction areas by securing the turn-on time of the inverter lower switches utilizing the DPWM(Discontinuous PWM) method, which results in the improvement of DC voltage utilization rate.

Efficient threshold logic in 1T1R array

In-memory computing based on memristor logic is one of the most promising approaches to break the ‘memory wall’ and ‘power wall’. However, some important logics (such as AND and MAJ) cannot be implemented efficiently in 1T1R arrays, which makes it difficult to design low-delay memristor-based logic computing systems. An efficient threshold logic is proposed by adding an auxiliary memristor in MAGIC (N+1)-OR gate and optimising the driving voltage. The proposed threshold logic can be completely implemented in a 1T1R array without any additional resistor, and can achieve AND logic and MAJ logic directly. Furthermore, a 1-bit full adder based on the proposed threshold logic, which only requires three steps and six memristors, is designed. Our proposed threshold logic and full adder design perform advantages in terms of area and delay compared with the previous designs.

First order universal filters employing single DV-EXCCCII

ABSTRACT This paper reports two filter circuits based on Differential Voltage Extra-X Current Controlled Current Conveyor (DV-EXCCCII). The first proposed circuit is a voltage-mode first-order universal filter that employs one DV-EXCCCII, one resistor, and one grounded capacitor. This circuit can realise all standard first-order filters, that is, low-pass, high-pass and all-pass filter. The second proposed circuit is a first-order multimode universal filter that employs a single DV-EXCCCII. This circuit can realise filter in current-mode, voltage-mode and trans-admittance mode with a single capacitor. However, a trans-impedance mode universal filter is realised with an additional resistor. Furthermore, the filter is electronically tunable with the bias current of DV-EXCCCII. The proposed filter circuits are verified using the SPECTRE simulator of CADENCE VIRTUOSO tool in 0.18 µm UMC CMOS technology parameters.

2 n -Way Wideband Filtering Power Dividers With Good Isolation Enhanced by a Modified Isolation Network

In this article, a class of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2^{n}$ </tex-math></inline-formula> -way wideband filtering power dividers (FPDs) is presented and designed with a wide isolation band. It consists of ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2^{n}-1$ </tex-math></inline-formula> ) two-way power-dividing units and <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> three-line coupled lines. The basic two-way power divider is achieved by replacing a simple isolation resistor of the conventional Wilkinson power divider with a modified isolation network, so as to improve the bandwidth of better-than-20-dB isolation band from 40% to 120%. The modified isolation network is composed of one quarter-wavelength coupled line, two quarter-wavelength transmission lines, and one resistor. The three-line coupled line is introduced at each output of the proposed FPD to improve its frequency selectivity and passband bandwidth. Furthermore, after placing one additional isolation resistor on each three-line coupled line, the number of output ports in the proposed power divider could be doubled without introducing more two-way power-dividing units. Finally, a prototype two-way and two prototype four-way wideband FPDs with different occupied sizes are designed and fabricated. The feasibility of the proposed design method is verified by the good agreement between the simulated and measured results.

A new approach to improving the sensitivity of earthing relay and reducing the over-voltage in 6 kV grid of open-pit mines

Purpose. Earthing relays are utilized very commonly in open-pit mines for disconnecting the failure part of 6 kV electric system from earthing incident. Much previous research is mentioned on searching either an optimal method for improving the effect of relays or improvements of reducing the overvoltage caused by grounding separately. The paper presents a new approach to not only improving the relays sensitivity but also to limiting the over-voltage. A new algorithm is also proposed to control automatic connection of an additional resistor in order to achieve both above mentioned purposes of 6 kV earthing relay. Methodology. The propose controlling diagram is implemented on PROTEUS to get 3U0 signals. The main components appeared when 6 kV feeders were faulted to earth. Afterward, the detecting signal is utilized as input for simulation diagram in MATLAB to get and analyze the wave forms of responded zero sequence voltage. Findings. The paper presents a new algorithm utilizing a resistor that is auto-controlled to auto-connect the open-triangle coil of 6 kV measurement transformer at the moment of earth fault. This automatic connection aims to increase the relay sensitivity as well as reduce the overvoltage. The finding results are sensitivity factors of relay and voltage magnitudes of healthy phases, which will be compared with corresponding values when there is no connection of resistor to prove the effectiveness of the method. Originality. A useful method is proposed for increasing the earthing current to enhance the sensitivity of earthing relay. Practical value. The proposed control diagram could be used to design a device aiming to improve the safety of 6 kV grid in open pit mines when earth faults occur.

Electrochemical behaviour of LiCl-KCl eutectic melts containing moisture as impurity. Part II: Uranium electrode

In Part I, LiCl-KCl eutectic melt purified by chlorine and LiCl-KCl + xwt.% H2O prepared by thermal equilibration of eutectic mixture with H2O at 500 °C were analysed for moisture content using acid-base titration. They were further investigated by electrochemical impedance spectroscopy (EIS) at inert tungsten electrode. It was established that cathodic reduction of H2O led to formation of OH- that adsorbed on tungsten electrode in potential range −0.80 to −1.50 V. The OH- film contributed to capacitive response as well as it offered a resistance to any other faradaic process occurring in that potential range. In this work, same LiCl-KCl eutectic melts were used to explore the anodic dissolution of uranium electrode in potential range −1.40 to −0.90 V by EIS. Complex impedance data in all melts were fitted to different equivalent circuit models. Presence of OH- film, which influenced the dissolution of uranium in LiCl-KCl + H2O melts, was modelled using additional resistor and constant phase elements in the equivalent circuit. Impedance data were further validated by Kramers-Kronig transforms where pseudo-χ2 values varied from 8.5×10−6 to 1.2×10−4 confirming a good compliance with spread of fit residuals across logω limited to less than ±3%. After EIS measurements, melts were again analysed by cyclic voltammetry and additional voltammetric features complicating the redox behaviour of U3+|U couple were analyzed.

Systematic Design and Circuit Analysis of Lightning Impulse Voltage Generation on Low-Inductance Loads

The well-known circuit for the generation of lightning impulse voltage (LIV) on low-inductance loads was introduced by Glaninger in 1975, and the circuit component selection was proposed by Feser. However, the circuit and the approach for the component selection have some difficulties for which further adjustment is required for obtaining the waveform parameters according to the standard requirement. In this paper, an extended Glaninger’s circuit with an additional series resistor is proposed. Furthermore, a systematic design and circuit analysis of LIV generation for low-inductance loads are developed. With the help of a circuit simulator, the circuit analysis for the component selection is described. The validity of the proposed circuit was confirmed by some experimental results in comparison with the simulated ones. The proposed circuit and component selection provide not only the generation waveform according to the standard requirement but also other promising performances in terms of the wide inductance load range from 400 μH to 4 mH, a voltage efficiency of over 80%, an overshoot voltage of below 5%, an undershoot voltage of below 40%, and a maximum charging capacitance of 10 μF. From the simulated and experimental results, the proposed circuit and component selection approach is very useful for the LIV tests on low-inductance loads instead of using the conventional approach based on trial and error.

Improved reversed nested miller frequency compensation techniques using flipped and folded flipped voltage follower with resistor for three stage amplifier

This paper presents three circuits to improve frequency compensation in three stage amplifier for large capacitive load of 100 pF. The first proposed circuit introduces Flipped Voltage Follower (FVF) in inner loop of Reversed Nested Miller Compensation (RNMC) to combat RHP zero whereas both second and third proposed circuits employ A Folded Flipped Voltage Follower (FFVF). The third proposed circuit uses an additional resistor in the outer compensation loop for double pole-zero cancellation. Further feed forward path has been used in all proposed circuits to improve the large signal response. The functionality is verified using TSMC 0.18 µm CMOS technology parameters in Tanner tool. The simulation results show maximum gain-bandwidth product (GBW) of 30 MHz, minimum phase margin (PM) of 60° and slew rate (SR) of 10 V/µS, and minimum common mode rejection ratio (CMRR) of 37.2 dB at unity gain frequency. The input-referred noise of the proposed circuits varies from 16.6 nV/Hz to 18.2 nV/Hzat unity gain frequency. Corner analysis is also included to show the robustness of the circuits.

A Dual-Mode Power Divider With Embedded Meta-Materials and Additional Grounded Resistors

This article presents a dual-mode power divider (PD) that offers new working mechanism, compact size, significant design freedom, wide working bandwidth, arbitrary power division, and ultrawide isolation between the two output ports. The structure is simple in comparison with conventional Wilkinson PDs in that only two composite right-and left-handed (CRLH) transmission lines (TLs) grounded through two resistors are used. Different from previous CRLH-TL-embedded studies in that almost all CRLH-TLs operate at quarter-wavelength phase responses, in the present work, the zero-degree property is noted and used to modify the impedance variation curves. Additionally, because of the use of grounded resistors, the proposed PD can operate in two modes, such that when high-value resistors are used, the PD operates in a lossless mode, while when low-value resistors are used, the PD operates in an attenuated mode. Because working power has been significantly improved due to progress in modern RF system development, more attenuation elements are required. This means that attenuated PDs will become very useful in the future. For verification, two PDs operating in different working modes and power divisions are designed and fabricated. Based on the experimental results, both PDs demonstrate good performance over more than 60% of the bandwidth with reference to the 15-dB S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> , ultrawide isolation, full port matching, and compact size.

Control system of induction motor drive of a hoisting unit with a controlled current converter in the rotor circuit

The use of a double-feed machine circuit is a promising way to modernize induction motor drives of mine hoisting installations. The main problem of using doubly-fed electric machine in the electric drives with a large range of speed control is the release implementation and machine operation of after it at low speed. Existing implementations of electric drives based on a doubly-fed machine (DFM) assume the use of additional resistors in the rotor circuit (rotor station) for releasing the brakes, which complicates the control circuit and significantly reduces the reliability of the drive. In this case, the electric drive circuit with additional active resistances in the rotor circuit has optimal starting characteristics, since a change in the active resistance of the rotor does not cause a change in the critical moment, and, therefore, in the overload capacity, which makes it possible to implement the release mode. It is possible to preserve the advantages of regulating the DFM speed by changing the active resistance of the rotor by using an imitation of its change. The article is devoted to the study of the possibility of implementing such mode using a controlled current converter in the rotor circuit.