Parallel Capacitor Research Articles

Penempatan Kapasitor Paralel pada Penyulang Pajajaran GI Jakabaring

In order to compensate for reactive power on electrical power distribution lines, parallel capacitors have been utilized extensively. Capacitor placement does not constantly improve the total voltage and power factor. Therefore, it is crucial to establish the ideal capacitance (size) and position of the capacitors to reduce power losses in the distribution line. Palembang City's New Jakabaring Substation is a substation situated in a region with a rapid load increase. Pajajaran Feeder, one of the several feeders at this substation, carries the weight of numerous significant loads as well as expanding residential areas. Reactive power computation and optimal capacitor placement (OCP) were the two simulation techniques used in the study, which were carried out using ETAP 19.0. The study's findings demonstrate that using reactive power calculations, the original Padjajaran feeder voltage drop is improved from 93.26% to 98.98% while utilizing OCP, the voltage drop is improved from 93.26% to 100.1%. However, OCP provides a more consistent capacitance value of the capacitors in the range of 930 kVAR compared to reactive power calculations, whose results are more inconsistent. Calculations using OCP gives more capacitors, namely as many as 20 more than those produced by calculating the reactive power of 14 capacitors. The location of parallel capacitors in the Padjajaran feeder can function optimally and support a load of up to 80% of the transformer capacity rating.

An improved simplified composite right‐/left‐handed zeroth‐order resonator and its application to design a compact microstrip bandpass filter with enhanced upper stopband

AbstractAn improved simplified composite right‐/left‐handed (SCRLH) zeroth‐order resonator (ISZOR) is introduced, comprising two lateral parallel capacitors and a centred T‐type inductor circuit. Starting from the lumped circuit of the ISZOR, its miniature microstrip layout can be generated with on more than three times full‐wave simulations by virtue of the implicit space mapping technique. Multi‐solutions of the microstrip ISZOR with identical fundamental mode are obtained by sweeping key physical and electrical parameters, uncovering the relationship among physical sizes, resonant modes, unloaded quality factors and circuit elements. A three‐pole microstrip Chebyshev bandpass filter (BPF) with ultra‐wide upper stopband is further designed. By choosing the constituent ISZORs with identical base frequency but different higher resonant frequencies and applying the over‐coupled I/O terminals, wideband spurious response suppression in the upper stopband is achieved. The target BPF centers at 3.1 GHz with a relatively bandwidth of 5%, which is optimised through a customised aggressive space mapping iterative process. The optimal BPF layout dimensions are automatically obtained with just a few time‐consuming full‐wave simulations. A prototype measurement shows the BPF features good bandpass selectivity in a simple and easy‐to‐fabricate structure, with a transversal size reduction of more than 65% compared to a former counterpart and a rejection level better than 15 dB over 40.0 GHz.

Design of a Hybrid Frequency Selective Rasorber With Wideband Reflection Suppression

A hybrid frequency selective rasorber is presented in this letter based on hybrid lossy layers. The hybrid lossy layers is composed of an absorption-transmission (A-T) layer and a transmission-absorption (T-A) layer, which are responsible for the absorption performance in the low and high frequency respectively. The A-T layer is composed of a lumped-resistors loaded cross-frame structure (CFS), which connects four parallel inductor and capacitor resonators. The T-A layer is constructed by a parallel plate capacitor loaded square loop resonator connecting four lumped-resistor loaded T-shaped metal branches. The frequency selective surface layer is composed of metal square slot. The hybrid frequency selective rasorber provides a transmission window around 10 GHz and two-sided absorption bands in 3.19—9 GHz and 11.85–21.18 GHz, meanwhile the wideband reflection suppression (S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> <−10 dB) is achieved from 3.2 to 21.18 GHz (147%). An assembled prototype is measured to verify the simulated results.

General Decoupling and Sampling Technique for Reduced-Sensor Battery Management Systems in Modular Reconfigurable Batteries

The capacity and voltage rating of battery packs for electric vehicles or stationary energy storages are increasing, which challenge battery management and monitoring. Breaking the larger pack into smaller modules and using power electronics to achieve dynamic reconfiguration can be a solution. Reconfigurable batteries come with their own set of problems, including many sensors and complex monitoring systems, high-bandwidth communication interfaces, and additional costs. Online parameter estimation methods can simplify or omit many of these problems and reduce the cost and footprint of the system. However, most methods require many sensors or can only estimate a subset of the elements in the module’s equivalent circuit model (ECM). This paper proposes a simple decoupling technique to derive individual modules’ voltage and current profiles from the output measurements without direct measurement at the modules. The determined profiles can achieve a high sampling rate with minimum communication between the battery management system (BMS) and the modules. With accurate profiles, an estimation technique can easily determine the parameters of the modules. Provided simulations and experiments confirm this claim by estimating the parameters of a first-order ECM with a parallel capacitor. The proposed technique reduces the number of sensors from 2N + 2 to only two at the pack’s output terminals.

An X-Band State Adjustable Low Noise Amplifier Using Current Reuse Technique

This article presents an on-chip state-adjustable 8 GHz~12 GHz low-noise amplifier (LNA). It has two characteristics. First, an improved current reuse topology is proposed. By connecting a small capacitor in parallel with the drain of the first-stage transistor, the bandwidth is expanded and the in-band flatness is improved. Second, an innovative adaptive bias circuit is designed to cope with the influence of temperature and process on the performance of the amplifier, and a design method for on-chip adjustment of the chip state is proposed for the first time. As a result of these technologies, the chip area is 1.1 mm × 0.8 mm, the chip provides 24.4 dB nominal gain with merely 0.75 dB noise at 10 GHz, and yields 14.5 dBm output power at 1 dB compression point (OP1dB) when biased at 30 mA quiescent current, meanwhile, gain, OP1dB, and quiescent current can be adjusted on-chip. This design improves the comprehensive performance of X-band LNA and provides more flexibility for system engineers in application. The chip is fabricated using Win Semiconductors’ 0.15 um InGaAs pHEMT E-mode process.

GPS위성 RF신호수신 이중대역 소형 하이브리드 결합기의 회로모델링과 설계

This paper presents a compact branch-line coupler working for receiving GPS signals at two adjacent frequencies as one geometry. The GPS receiver must have the feed circuit handling a circularly polarized electric field entering the radiating element leading up to division into quadrature branches, which has been used in the conventional works. But, it takes one frequency and a new approach is needed to take two frequencies. A lattice comprising segments loaded with series and parallel capacitors and circumferential inductors is built to make the branch-line coupler handle two frequencies. L1 and L2 bands for GPS are chosen and the circuit modelling is conducted to design the component. The method is verified by running a microwave circuit simulator and measurement of the s-parameters of the fabricated prototype. The power division and reflection coefficient at 1.5 GHz as L1- and 1.2 GHz as L2-band show the result is in good agreement with the required performance.

Enhanced self-sensory measurements for smart carbon-based textile reinforced cement structures

This study explores advanced capabilities of smart carbon-based textile reinforced cement-based elements to monitor its structural health. The goal is to enhance and amplify the electrical measurements and the sensitivity of the electrical readings. To answer these goals, the study develops advanced alternating current (AC) based electrical measurement setups. The study also offers to use a new cementitious matrix with enhanced mechanical, rheological and electrical properties. To amplify the measurement, the study suggests measuring the electrical changes at the resonance frequency of the system, which can be done by connecting external capacitors to the embedded carbon roving. A comparison investigation is performed to explore the monitoring capabilities of four electrical measurement setups at various structural states. Eight textile and fibers reinforced cement-based beam specimens were investigated under flexural loading. It is found that by connecting an external parallel capacitor to the roving, amplified, stable and sensitive electrical measurements are achieved.

Development of Embroidery-Type Sensor Capable of Detecting Respiration Using the Capacitive Method.

This study presents a respiration sensor that is dependent on a parallel capacitor, including connection lines and electrodes embroidered on textiles. First, characterizations of the respiration capacitor using a silver thread, including a combination of porous Eco-flex simulating air in the lungs due to respiration, were evaluated using an LCR meter. Second, the effects of air gaps on the detection of respiration motions according to the change in electrode distance under pressure were presented. The data values were measured from 1 to 300 kHz using an LCR meter and dielectric test fixture. Third, actual breathing was examined in four patterns: normal breathing, deep breathing, hyperventilation, and apnea. The test was performed after fabricating a clothing-type breathing sensor. Finally, the change in capacitance for actual respiration was determined by wearing a clothing-type respiration sensor based on the data collected. The effectiveness of the respiration sensor was demonstrated by measuring it to discern all waveforms, cycles, and ranges associated with the breathing pattern.

The design of [formula omitted]-ADC in MEMS gyro interface ASIC

This article aims at MEMS gyroscope fully differential (FD) sensing, small signal output characteristics, designs a FD third-order cascade of integrators with feedforward (CIFF) delta-sigma analog-to-digital converter (ΔΣ-ADC). Abandoning the local negative feedback in the general third-order CIFF to reduce the difficulty of layout design. And under the premise of ensuring accuracy and stability, discarding the path directly from the input to the quantizer to reduce the circuit area and the influence of harmonics on the signal-to-noise-distortion ratio (SNDR) caused by the input sampling. In order to reduce the mismatch of capacitors, the gain factor and feedforward factor are optimized, so that each factor only retains one decimal place, and all capacitors on the layout are composed of 0.2pF unit capacitors in parallel. The tape-out measurement results show that the SNDR of the ΔΣ-ADC chip is 50.13 dB in the bandwidth (BW) range of 1kHz to 11kHz, and the input signal amplitude range is 1 mV to 800 mV.

Aluminum Nitride-Based Adjustable Effective Electromechanical Coupling Coefficient Film Bulk Acoustic Resonator.

The arrival of the 5G era has promoted the need for filters of different bandwidths. Thin-film bulk acoustic resonators have become the mainstream product for applications due to their excellent performance. The Keff2 of the FBAR greatly influences the bandwidth of the filter. In this paper, we designed an AlN-based adjustable Keff2 FBAR by designing parallel capacitors around the active area of the resonator. The parallel capacitance is introduced through the support column structure, which is compatible with conventional FBAR processes. The effects of different support column widths on Keff2 were verified by finite element simulation and experimental fabrication. The measured results show that the designed FBAR with support columns can achieve a Keff2 value that is 25.9% adjustable.

Modelling of a piezoelectric beam with a full-bridge rectifier under arbitrary excitation: experimental validation

Abstract This paper presents a set of nonlinear differential equations to model a piezoelectric energy harvesting (PEH) system with a full-bridge waveform rectifier (FWR) under arbitrary base excitations. The PEH comprises a piezoelectric element modeled as a current source with a capacitor in parallel, which are connected with an inductor and a resistor. The inductor is proposed to smooth the current generated by the piezoelectric element under rapid mechanical variations and improve the convergence of the set of differential equations. The equations are obtained using piecewise linear modelling for the diodes. The main advantage of this piecewise linear modelling is considering different bias points to represent the nonlinear characteristics of real diodes. Numerical simulations are employed to obtain the optimum inductor value through a comparison with an analytical result, validated with experimental tests. A real case of random acceleration in a bike is applied to the PEH-FWR to evaluate the performance of the proposed equations. They are validated with experiments, a LTspice formulation and a numerical previous one. The proposed formulation can estimate the output DC voltage and energy for a large range of excitation frequencies, including resonant and nonresonant conditions and arbitrary or harmonically externally excited PEHs with FWR.

A compact lumped‐element two‐way differential to single‐ended Wilkinson power combiner with embedded impedance transformation

AbstractThis letter presents a compact lumped‐element two‐way differential to single‐ended Wilkinson power combiner with embedded impedance transformation. It consists of two transformer baluns and two parallel resistance and capacitor (RC) branches. The two transformers generate high‐order impedance transformation networks at even‐mode operation and form resonators together with the two parallel RC branches at odd‐mode operation, thus achieving broadband impedance matching and power combining with a compact area. A proof‐of‐concept prototype working at 1.7 GHz is designed and fabricated. Measurement results show that the peak isolation is 24.5 dB, insertion loss is from 0.34 to 1.15 dB and magnitude and phase imbalance are within 0.1 dB and , respectively, over the frequency range from 1.37 to 1.97 GHz. The area is only 6.54 mm 6 mm.

Proteus/Simulink Analysis of Rectifier based E-Vehicle Charger Circuit

In this paper, an AC to DC rectifier circuit has been discussed and the simulation results are provided. This converter is very useful for the upcoming development of the electric vehicles charging technology. For producing steady DC from a rectified AC supply requires a smoothing circuit or filter. The main purpose of the filter circuit is to remove the ripple or ac components from the output of the diode circuit. So, to make the output DC pure, the filter circuit is used. The filter circuit may be inductive (built with only inductors in series) or capacitive (built with only capacitors in parallel) or Inductive-Capacitive (built with both inductors and capacitors). A voltage regulator which is used to maintain the constant output DC voltage. Design of the controller is detailed for reference. The converter will operate in continuous conduction mode (CCM). Finally, some selected experimental results are presented to verify the proposed theory.

A Low Switch Count 13-Level Switched-Capacitor Inverter With Hexad Voltage-Boosting for Renewable Energy Integration

Switched-Capacitor multilevel inverters (SCMLI) are being explored for renewable power applications like solar-PV integration because of their benefits of low component count and low-cost factors. This work presents and explores a new multilevel inverter with a hexad voltage-boosting capability. It employs a single source and produces a 13-level waveform by utilizing only fourteen switches, two diodes, and four capacitors. The voltage across the capacitors is maintained at the desired magnitudes during the switching of the inverter by connecting the DC source and capacitors in parallel at several time locations in one operating cycle. The topology proposed in this work is compared with the recent 13-level topologies in terms of switches, diodes, capacitors, and cost factors (CF). A level-shifted PWM-based algorithm generates the circuit switches’ PWM pulses. The CF of the proposed SCMLI is found to be 2.461, which is the lowest among the compared hexad-boosted MLIs. Experimental validation is performed on a hardware prototype to validate various operational conditions of load change, modulation index change, and reference frequency change.

Analysis and Design of the Suboptimum Class-EM/F3 Resonant Inverter

In this paper, the analysis and design method for the suboptimum Class- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{E}_{\mathrm {M}}/\text{F}_{3}$ </tex-math></inline-formula> inverter (i.e., only the zero-voltage switching (ZVS), the zero-voltage-derivative switching (ZVDS), the zero-current switching (ZCS) conditions are satisfied) with a duty ratio D =0.5 are presented. In the proposed design method, a new design parameter K called the slope of switch current (when the switch turns off) is introduced for defining the suboptimum degree and the distance from the optimum condition. By using the design method of the soft switching resonant inverter, the third harmonic filter circuit is innovatively introduced to reduce the current flowing through the parallel capacitor of the main circuit, and greatly reduce the peak switching voltage of the main circuit and auxiliary circuit. And the circuit waveforms and design equations can be derived in detail. Compared with the conventional Class- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{E}_{\mathrm {M}}$ </tex-math></inline-formula> inverter, the proposed inverter can offer the much lower peak switching voltage and higher efficiency. To verify the validity of the proposed method, a Class- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{E}_{\mathrm {M}}/\text{F}_{3}$ </tex-math></inline-formula> inverter operating at 1MHz is designed using the IRFZ24N transistor. The experimental results show that the output power of the new inverter is 15.138W, the efficiency reaches 96.4%, and the peak switching voltage of the main circuit and auxiliary circuit is reduced by 29.3% and 15.6%, respectively. The PSpice-simulation results and the experimental measurement results of the designed inverter are agreed with the analytical results, which verified the effectiveness of the proposed design method.

Turbo Expander Generator(TEG)를 이용한 자체기동 발전기 대체 관한 연구

In supplying natural gas to the city, Korea Gas Corporation manufactures a TEG generator using the energy that lowers the gas pressure, and conducts research to demonstrate the application. Since TEG is a facility that generates electricity using only natural gas pressure, it is characterized by being able to generate electricity without any other special energy source. This is similar to a hydroelectric generator and can be used as a self-starting generator that is first started to recover when a power outage occurs throughout the power system. In this paper, since the location where TEG generators are currently being demonstrated corresponds to southern Gyeongin in terms of the procedure for restoring the system in the event of a power outage, we propose a plan to replace self-starting generators in southern Gyeongin with TEGs and restore the power system. Replacing the self-starting generator with TEG, confirming through simulation whether the priority starting generator can operate through the transmission line, and reflecting the characteristics of the TEG generator consisting of an induction generator, the amount of reactive power required to pressurize the transmission line and the power required to supply the priority start generator was analyzed. It was confirmed that the TEG generator can produce the same output as the self-starting generator by using the charging current charged from the trial transmission line and the additional parallel capacitor. In the future, TEG will be used not only as a self-starting generator, but also as a generator that can provide inertia to contribute to the stabilization of the power system.

Highly efficient plasma generation in inductively coupled plasmas using a parallel capacitor

A highly efficient plasma source is developed in inductively coupled plasmas (ICPs) using a parallel capacitor, which is connected to an antenna in parallel. The power absorbed by the ICP is proportional to the equivalent resistance of the ICP. In order to improve the plasma generation, a parallel resonance is used between the parallel capacitor and the equivalent inductance by the plasma and the antenna. In all experiments conducted under an H-mode regime where the inductive heating is dominant, the resistance of a load involving the plasma increases about ten times near the resonance, and the power consumed by the plasma is greatly increased. Consequently, the electron density is greatly increased up to about 350% in the argon plasma and is significantly increased up to about 1000% in the oxygen plasma. For analysis, the transformer model of the ICP and the power balance equation of the global model are introduced, and they show good agreement with the experimental results.

Influence of CO2 Curing on the Alkali-Activated Compound Mineral Admixtures’ Corrosion Resistance to NaCl Dry–Wet Alternations

In this study, the influence of CO2 curing on the corrosion resistance of reinforced alkali-activated compounds is investigated. Fly ash (FA) and blast furnace slag powder (BFS) are used as mineral admixtures. The specimens were subjected to dry–wet alternations with 3% NaCl, used to simulate a concrete structure under a corrosion environment. The ultrasonic velocity, mass loss rate, and electrical characteristics (such as electrical resistance, AC impedance spectra, and corrosion area rates determined by Tafel curves) are utilized to determine the degree of corrosion. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) are used to analyze the corrosion mechanism. Results show that the corrosion resistance is decreased by the addition of FA but improved by CO2 curing. When CO2 curing is provided, the addition of BFS shows a higher enhancing effect on the corrosion resistance than that of FA. The equivalent circuit diagram of reinforced alkali-activated compound mineral admixtures obtained by AC impedance spectra is composed of three electrical elements (electrical resistance and capacitance in parallel) in series. The X-ray diffraction results show that adding BFS and CO2 curing can decrease the rust’s iron oxides on the steel bars’ surface. Finally, as found in the SEM photos, BFS and CO2 curing can effectively improve the compactness of specimens. Meanwhile, the roughness of hydration is increased by CO2 curing.

Optical and temperature dependent electrical properties of poly (vinyl chloride)/copper alumina nanocomposites for optoelectronic devices

Abstract The practical applications of poly (vinyl chloride) have been constrained due to its poor thermal stability, low dielectric constant and inability to shield against ultraviolet (UV) radiation. In this study, we tried to improve the optical properties, thermal stability, temperature-dependent electrical conductivity and dielectric constant using copper alumina (Cu–Al2O3) nanoparticles reinforced poly (vinyl chloride) (PVC). Optical absorption measured with an ultraviolet-visible (UV-visible) spectrometer emphasises the blueshift in absorption edges and decreasing bandgap energies of PVC/Cu–Al2O3 nanocomposites compared to PVC. The presence of Cu–Al2O3 in PVC and its interaction with the polymer were confirmed by FTIR spectroscopy. Thermogravimetric analysis (TGA) demonstrates that nanocomposites have higher thermal stability than PVC, and that thermal stability increases with filler loading. Scanning electron microscopy (SEM) indicates the homogeneous dispersion of nanosized Cu–Al2O3 in the polymer matrix. The activation energy determined by the Arrhenius equation revealed that AC conductivity increases with the addition of nanoparticles up to a specific loading. The dielectric constant increases as a function of temperature and decreases with frequency. The magnitude of AC conductivity and dielectric constant were highest for 7 wt% loaded nanocomposites. The dielectric constant predicted by the Bruggeman and Maxwell-Garnet models were in good agreement with the experimental permittivity. The semiconducting nature of nanocomposites was investigated by impedance analysis. The semi-circular nature of Cole-Cole plots manifests the combination of parallel capacitance with low bulk resistance. The enhanced optical, thermal, electrical and dielectric properties of PVC/Cu–Al2O3 nanocomposites can be utilized in fabricating optoelectronic devices with excellent charge-storing ability.

Power Factor Correction and Harmonic Control in Industries

Abstract—Due to rising electricity prices, wastage of electrical energy needs to be reduced through countering the electric pollution in the circuit. Power factor correction and harmonics control is necessary in industries. Power factor correction can be done through placing capacitors in parallel in the circuit. Power factor of nearly 1 is the most efficient. Harmonics can be controlled with the help of linear reactors. In this paper we will discuss about the power factor correctors and linear reactors for harmonic attenuation. Keywords—Power factor, linear reactor, harmonics, power quality.