Showing papers on "RC circuit published in 2020"

The transient analysis for zero-input response of fractal RC circuit based on local fractional derivative

Abstract: Local fractional calculus has gained wide attention in the field of circuit design. In this paper, we propose the zero-input response(ZIR) of fractal RC circuit modeled by local fractional derivative(LFD) for the first time. With help of the law of switch and the Kirchhoff Voltage Laws, the transient local fractional ordinary differential equation is established, and the corresponding exact solution behavior defined on Cantor sets is presented. What we found especially interesting was that the fractal RC becomes the ordinary one in the particular case κ = 1. The results obtained in this paper reveal that the local fractional calculus is a powerful tool to analyze the fractal circuit systems.

A Parameter Extraction Method for the Li-Ion Batteries With Wide-Range Temperature Compensation

Abstract: An accurate battery model is essential for precise estimation of battery performance indicators, such as state of charge (SoC), state of health (SoH), etc. It helps in determining the optimum energy management and therefore, optimum utilization of the battery capacity. Some of the battery model parameters may change with the variation of environmental conditions, such as operating temperature, and therefore, accurate temperature compensated model estimation is necessary to minimize the error in battery model and SoC estimation. This article presents a novel parameters extraction method for the Thevenin equivalent circuit model of Li-ion batteries considering their resiliency on temperature effect. The proposed approach represents each of the RC parallel circuits of the Thevenin-based equivalent circuit battery model as a first-order linear time-invariant (LTI) system. The resistance and capacitance values for each of the RC circuits in the model have been identified as the parameters of a standard LTI system using the system identification theory and represented them as the temperature-compensated model parameters. The proposed model can be applied to various applications, such as SoC, SoH estimation, and battery energy management. In order to demonstrate the suitability of the proposed modeling approach, the model is augmented with the conventional extended Kalman filter to enable accurate SoC estimation under varying operating temperatures. The accuracy and effectiveness of the proposed modeling approach and its suitability to enhance SoC estimation under a wide operating temperature range ( $-$ 5 to 45 $^\circ$ C) have been validated through laboratory experiments in the LabVIEW platform.

Electrothermal-Based Junction Temperature Estimation Model for Converter of Switched Reluctance Motor Drive System

Abstract: In this paper, an electrothermal-based junction temperature estimation model is proposed for an asymmetric half-bridge converter of a switched reluctance motor drive system. In the current chopping control mode, there exists a particularly uneven temperature distribution on converters due to not only the thermal coupling effects and dissipating boundary conditions, but also the different device losses in the same phase bridge. For the purpose of precise estimation for junction temperature, first, the power loss of converter is accurately calculated by the interpolation method with the help of Simulink and LTspice. Second, the thermal coupling effects and dissipating boundary conditions are analyzed in the three-dimensional finite-element method (FEM) model. According to the step power response extraction, a coupling impedance matrix is used to describe the nonnegligible thermal coupling effects between devices, and the complete heatsink can be decoupled into multiple subdivisions that represent the different heat dissipating boundary conditions. Then, with coupling impedances and subheatsink impedances in series, a compact RC network model can be built for junction temperature estimation. Consequently, analytical investigation in conjunction with FEM simulation and experiment measurements demonstrate the validity of the proposed model.

On the comparison of three numerical methods applied to building simulation: Finite-differences, RC circuit approximation and a spectral method

Abstract: Predictions of physical phenomena in buildings are carried out by using physical models formulated as a mathematical problem and solved by means of numerical methods, aiming at evaluating, for instance, the building thermal or hygrothermal performance by calculating distributions and fluxes of heat and moisture transfer. Therefore, the choice of the numerical method is crucial since it is a compromise among (i) the solution accuracy, (ii) the computational cost to obtain the solution and (iii) the complexity of the method implementation. An efficient numerical method enables to compute an accurate solution with a minimum computational run time (CPU). On that account, this article brings an investigation on the performance of three numerical methods. The first one is the standard and widely used finite-difference approach, while the second one is the so-called RC approach, which is a particular method brought to the building physics area by means of an analogy of electric circuits. The third numerical method is the spectral one, which has been recently proposed to solve nonlinear diffusive problems in building physics. The three methods are evaluated in terms of accuracy on the assessment of the dependent variable (temperature or vapor pressure) or of density of fluxes for three different cases: (i) heat diffusion through a concrete slab, (ii) moisture diffusion through an aerated concrete slab and (iii) heat diffusion using measured temperatures as boundary conditions. Results highlight the spectral approach as the most accurate method. The RC based model with a few number of resistances does not provide accurate results for temperature and vapor pressure distributions neither to flux densities nor conduction loads.

DC Fault Analysis Models of Three Converter Topologies Considering Control Effects

Abstract: Existing converter models are normally reduced as simplified electrical components, whereas it overlooks the impacts of fast dynamics of converter current control loops. Therefore, the dc fault current calculation with the traditional simplified converter models becomes invalid when the simulation time is longer. To overcome this problem, this article incorporates the control effects of converters during the transient process and proposes three dc fault analysis models of classical three converter topologies for the high-voltage dc (HVdc) application including line communicated converter (LCC), two-level voltage-source converter (VSC), and modular multilevel converter (MMC). For an LCC-based rectifier, the nonlinear part of original model is first linearized with the least square method due to the large dc-link voltage deviation during dc fault, and the proportional integral (PI) current regulator with the reduced linearized model can be equivalent as an RC circuit for dc fault analysis. However, for two-level VSC or MMC, the dc-link voltage deviation does not drop that much with a large dc-link capacitor discharging process during transient dynamics. As a result, the original model is linearized relying on the small-signal method based on prefault operation points, and the dynamics of fast inner current loop with the linearized model can be represented as an RL circuit for dc fault current calculation. for dc fault analysis The proposed dc fault analysis models of three converters as equivalent RLC circuits are well testified under different fault resistances and dc reactors, control parameters, and operating conditions. Moreover, dc fault simulations of a hybrid HVdc system have verified the effectiveness of the proposed converter models.

Robust electrical parameter extraction methodology based on Interior Search Optimization Algorithm applied to supercapacitor.

Abstract: Supercapacitor (SC) is completely valuable as an energy storage device for different applications such as electric vehicles and hybrid renewable systems. A simple SC model that composed of series RC circuit is insufficient to precisely characterize its dynamic performance. Consequently, an accurate mathematical model must be created for reliable and safe operation of SC. The equivalent circuit model that contains three RC branches, immediate, delayed and long is considered, the first branch includes voltage-dependent capacitance. The second one determines the terminal behavior in minute-time range while the last branch determines the behavior for time longer than 10 min. Such model has eight unknown parameters to be determined. A new formula to estimate the SC voltage is derived. For first time Interior Search Algorithm (ISA) is employed to identify these parameters. The obtained results are compared with those obtained by other different optimization algorithms like Genetic Algorithm (GA), Moth Flam Optimization (MFO), Antlion Optimizer (ALO), Gray Wolf Optimizer (GWO), Whale Optimization Algorithm (WOA), and Artificial ecosystem-based optimization (AEO). Two different capacitors with values of 470-F and 1500-F are considered during the validation process. Extensive statistical analysis is carried out to prove the reliability of the proposed methodology. The results confirmed high level of agreement between experimental data and optimized model circuit.

A 33-ppm/°C 240-nW 40-nm CMOS Wakeup Timer Based on a Bang-Bang Digital-Intensive Frequency-Locked-Loop for IoT Applications

Abstract: This paper presents a wakeup timer in 40-nm CMOS for Internet-of-Things (IoT) applications based on a bang-bang Digital-intensive Frequency-Locked Loop (DFLL). A self-biased $\Sigma \Delta $ Digitally Controlled Oscillator (DCO) is locked to an RC time constant via a feedback loop consisting of a single-bit chopped comparator and a digital loop filter, thus maximizing the use of digital circuits while keeping only the RC network and the comparator as the sole analog blocks. Analysis and behavior level simulations of the DFLL have been carried out to guide the optimization of the long-term stability and frequency accuracy of the timer. High frequency accuracy and a $10\times $ enhancement of long-term stability is achieved by the adoption of chopping to reduce the effect of comparator offset and 1/f noise and by the use of $\Sigma \Delta $ modulation to improve the DCO resolution. Such highly digitized architecture fully exploits the advantages of advanced CMOS processes, thus enabling operation down to 0.7 V and a small area (0.07 mm2). The proposed timer achieves the excellent energy efficiency (0.57 pJ/cycle at 417 kHz at 0.8-V supply) over prior art while keeping excellent on-par long-term stability (Allan deviation floor < 20 ppm) and temperature stability (33 ppm°Cat 0.8-V supply).

Development of an Equivalent Circuit for Batteries Based on a Distributed Impedance Network

Abstract: This paper presents an original equivalent battery model based on a distributed RC circuit. The model virtually includes an infinite number of time constants to reflect the battery behavior, especially during the dynamic stress test. The model has much fewer parameters than the traditional battery model and so reduces the parameterization effort significantly. The self-discharge is inherently implemented in the model as well. The second order partial differential equation of the model is derived and both explicit and numerical solution approaches are introduced to incorporate the model in any simulation environment or analytical response analysis. Incorporating the effect of the state of charge on the parameters of this model is more easily accomplished by changing the trends of the parameters as opposed to each of them individually. The model matches to various battery type and it is validated on a 30 Ah Lithium-Ion battery from 1 C to 8 C discharge pulse current. Furthermore, the results are compared to the classic battery model.

Mathematical and statistical analysis of rl and rc fractional-order circuits

Abstract: The RL and RC circuits are analyzed in this research paper. The classical model of these circuits is generalized using the modern concept of fractional derivative with Mittag-Leffler function in it...

A 3-MHz 17.3- $\mu$ W 0.015% Period Jitter Relaxation Oscillator With Energy Efficient Swing Boosting

Abstract: This brief presents a low-power RC relaxation oscillator with low period jitter for sensor interface applications. A switched capacitor RC network is proposed to boost the timing capacitor voltage swing with high energy efficiency, so that the output jitter can be effectively reduced. An inverter-based comparator with replica bias is used for switching threshold tracking under the supply variation. Implemented in a standard 65nm CMOS process, the proposed oscillator achieved 3.0 MHz output frequency with 0.015% relative period jitter and consumed 17.3- $\mu \text{W}$ power under 1 V supply voltage. The frequency variation is ±0.15% over a supply range of 0.95 V to 1.45 V and ±0.6% for temperature across 0°C to 90°C, respectively. The circuit achieved a Figure of Merit (FOM) of 161 dBc/Hz and the total energy efficiency is 5.7 pJ/cycle.

Mathematical Modelling of Simple Passive RC Filters Using Floating Admittance Technique

Abstract: This article describes mathematical modeling of simple L-, T - and π-type filters focused with the solutions using Floating Admittance approach. The solution using Floating Admittance Matrix is very attractive for any kind of circuits considering the size and complexity.

Novel resistor-capacitor (RC) network-based capacitance signal conditioning circuit for tip clearance measurement on gas turbine engine

Abstract: Blade tip clearance is a critical engine health parameter measured on gas turbines. Increase in tip clearance results in decreased efficiency, whereas with decrease in clearance due to thermal and ...

RF Reflectometry for Readout of Charge Transition in a Physically Defined PMOS Silicon Quantum Dot

Abstract: We have embedded a physically defined p-channel silicon MOS quantum dot (QD) device into an impedance transformer RC circuit. To decrease the parasitic capacitance and surpass the cutoff frequency of the device which emerges in MOS devices that have a top gate and act as RC low-pass filter, we fabricate a new device to reduce the device's top gate area from 400 $\mbox{$\mu$m}^2$ to 0.09 $\mbox{$\mu$m}^2$. Having a smaller top gate eliminates the cutoff frequency problem preventing the RF signal from reaching QD. We show that we have fabricated a single QD properly, which is essential for RF single-electron transistor technique. We also analyze and improve the impedance matching condition and show that it is possible to perform readout of charge transition at 4.2 K by RF reflectometry, which will get us to fast readout of charge and spin states.

Investigation of Adaptive Synchronous Rectifier (SR) Driving Scheme for LLC/CLLC Resonant Converter in EV On-Board Chargers

Abstract: For LLC/CLLC resonant converters, synchronous rectifiers (SR) are desired to be turned off at the current zerocrossing moment to avoid the additional conduction loss and the circulation current In this paper, an adaptive SR driving scheme is proposed for LLC/CLLC resonant converter, which guarantees the ZCS turn-off of the SRs and improves the system efficiency The proposed method senses the drain-to-source voltage of only one switch, which makes it easy to implement Meanwhile, a simple drain-to-source voltage sensing circuit is proposed The proposed circuit can be directly interfaced with the digital controller without any signal conditioning circuit Moreover, external RC circuits are employed to compensate the turnon moment discrepancy between the SR and its corresponding primary side switch A 66 kW/500 kHz CLLC resonant converter prototype is built, which is used as the isolated dc-dc stage for an EV on-board charger The proposed adaptive driving scheme is validated by experimental tests

Third-Order Fractional-Step Band-Pass Filters

Abstract: In this paper a third-order band-pass (BP) filter with geometrically-symmetrical characteristic is presented, for the first time to the authors knowledge. This filter characteristic is only possible to be obtained by fractional-order (FO) filter design. The desired characteristic was Chebyshev 0.1dB pass-band ripple and with normalized bandwidth $\mathrm{B}=0.1$ . Starting from common fourth-order BP transfer function the design was performed numerically using the nonlinear trust-region-reflective, least square algorithm in Matlab. The resulting third-order BP filter approximates very well in the pass-band frequency region, while possessing fractional step in the stop band. The wanted BP transfer function is realized as cascade in two ways: biquads with integer order (IO) and biquads with FO. The obtained design parameters in the IO and FO realizations are compared. Approximation of the constant phase element by Foster I passive RC network is used in a Pspice analysis. That Pspice analysis in a frequency and a time domain are confirming the realizability and stability of the proposed filter, respectively.

A simple analysis of polarization reversal of ferroelectric capacitor demonstrating negative capacitance-like behavior

Abstract: Polarization reversal of a ferroelectric capacitor with a load resistance has been calculated by the Kolmogorov–Avrami–Ishibashi (KAI) model. Polarization change, current response and voltage across the ferroelectric capacitor were calculated and then the total charge density was plotted as a function of voltage across the ferroelectric capacitor to reconstruct polarization-electric field relation. Negative capacitance-like behavior was observed due to the voltage drop across the load resistance caused by the switching current of ferroelectric polarization reversal. In addition, circuit and switching parameter dependences on the negative capacitance-like behavior are discussed. It is shown that a dimensionality factor in the KAI model formulation affects the negative capacitance-like behavior. The presented calculation results indicate that the switching current during the polarization reversal is important to observe the negative capacitance-like behavior in the pulse response of the RC circuit with a ferroelectric capacitor, which is essentially different from the originally proposed concept of negative capacitance.

Theoretical and Experimental Analysis of Energy in Charging a Capacitor by Step-Wise Potential

Abstract: In this paper, charging capacitor in RC circuit, to a final voltage, via arbitrary number of steps, is investigated and analyzed both theoretically and experimentally. The obtained results show that the stored energy in the capacitor is constant independent of N, but the dissipated energy in the resistor and the consumed energy by the power supply decreases as number of steps N increases (adiabatic charging). The limit when the step number goes to infinity is examined and our result shows that the dissipated energy vanishes theoretically. This limit is carried out experimentally by using a ramp potential.

Minimum phase bipolar converter for DC microgrid applications

Abstract: This study proposes a minimum phase bipolar converter for dc microgrid applications, which is derived from the combination of C'uk and Sepic converters with some modifications in both of them in order to get a minimum phase system. In the proposed bipolar converter (PBC), the equivalent series resistance of transfer capacitors of both C'uk and Sepic converters is increased by adding resistances and introducing magnetic coupling between the filter inductors of the Sepic converter with a series RC network. These circuit modifications eliminate right half plane zero from the PBC and thereby make it a minimum phase, unlike the conventional C'uk-Sepic bipolar converter. Due to the minimum phase behaviour, the proposed converter can deliver high load current, achieves high bandwidth and facilitates simpler controller design in contrast to the conventional C'uk-Sepic bipolar converter. Detailed steady state and dynamic modelling of the PBC has been carried out in order to show its advantages. A 500 W laboratory prototype has been developed and implemented using field programmable gate array-based system to verify the operation of the proposed converter.

Differential Difference Amplifiers in the Second Order Low-Sensitive All-Pass Active RC-Filters

Abstract: We have developed the second order all-pass active RC-filter‘s (ARCF) architecture based on two differential difference amplifiers. The suggested low-sensitive ARCF provides an amplitude-frequency responses' (AFR) complete set (low pass filter LPF, high pass filter HPF, band pass filter BPF, rejection filter RF) for signal frequency selection's typical tasks in instrument engineering, communication, automatics. The said ARCF is differentiated by the following: its transfer ratio and pole frequency are not changed, when the pole Q-factor is adjusted. Here a concrete type filter's implementation is provided by using ARCF's different inputs and different outputs. We have given analytical expressions, which allow ARCF's parametric synthesis. We have discussed the computer simulation results for amplitude-frequency responses of LPF, HPF, BPF and RF. We recommend applying ARCF in specialized structured arrays, which are advanced in frequency selection devices' small volume production conditions and special operation condition requirements (neutron flux, low temperatures etc.).

Equivalent-circuit-based Stability Analysis of non-Foster SCS Negative Capacitor

Abstract: Equivalent circuit of a non-Foster negative capacitor, based on an SCS voltage-inversion negative converter with one-pole and two-pole amplifier model, has been developed. The circuit was loaded with an external RC network of series or parallel type, and the stability of the whole system is investigated. It was found that there is always a trade-off between operating bandwidth and the range of external capacities and resistances that assure stable operation.

Asymptotic Analysis for Overlap in Waveform Relaxation Methods for RC Type Circuits

Abstract: Waveform relaxation (WR) methods are based on partitioning large circuits into sub-circuits which then are solved separately for multiple time steps in so called time windows, and an iteration is used to converge to the global circuit solution in each time window. Classical WR converges quite slowly, especially when long time windows are used. To overcome this issue, optimized WR (OWR) was introduced which is based on optimized transmission conditions that transfer information between the sub-circuits more efficiently than classical WR. We study here for the first time the influence of overlapping sub-circuits in both WR and OWR applied to RC circuits. We give a circuit interpretation of the new transmission conditions in OWR, and derive closed form asymptotic expressions for the circuit elements representing the optimization parameter in OWR. Our analysis shows that the parameter is quite different in the overlapping case, compared to the non-overlapping one. We then show numerically that our optimized choice performs well, also for cases not covered by our analysis. This paper provides a general methodology to derive optimized parameters and can be extended to other circuits or system of differential equations or space–time PDEs.

Optimal Adjustment of Double Exponential Model Parameters to Reproduce the Laboratory Volt-Time Curve of Lightning Impulse

Abstract: This paper develops an optimization model to find the optimal values for the parameters of the double-exponential function. This function can be used to reproduce the volt-time curves of the standard and nonstandard applied impulse voltages in a software environment. Reproducing a similar applied laboratory impulse voltage in a software environment plays a crucial role in obtaining precise results and validates the model to be applied for further studies. In the literature, most of the papers use the existing standard and nonstandard models in which either an RC circuit has been used or a trial and error method has been used to approximately reproduce the applied impulse. However, more often than not, inappropriate adjustments cause a large error in the outcome results. Therefore, the proposed optimization-based approach can act as a facilitating tool for reproducing the nonstandard volt-time curves as close as possible to the laboratory applied impulse. The proposed model is verified by reproducing the volt-time curve of a 125 kV impulse voltage. Comparing the simulated impulse with the experimental impulse voltage shows the usefulness and effectiveness of the proposed approach in adjusting the sensitive parameters of the double-exponential function in EMTP-RV (Electromagnetic Transients Program) software.

5G mobile network node detection system based on cloud calculation

Abstract: The invention discloses a 5G mobile network node detection system based on cloud calculation. The device comprises a signal sampling module and a feedback adjusting module, the signal sampling modulesamples communication base station node signals in the 5G mobile network node detection system based on cloud calculation. The signal sampling module is connected with the feedback adjusting module; an output signal of the feedback adjustment module is filtered by an RC circuit consisting of a resistor R4 and a capacitor C2; an MOS tube Q3 is used for detecting an output signal of an operational amplifier AR2 and an emitter potential difference of a triode Q2. The feedback abnormal signal is further calibrated by a voltage regulating circuit consisting of an operational amplifier AR4 and an operational amplifier AR3; an operational amplifier AR5 is used for further comparing an output signal of the operational amplifier AR3 with an emitter signal potential of a triode Q1; and finally, the5G mobile network node detection system terminal based on cloud calculation can make an accurate response to a serious congestion phenomenon in a transmission network of a network base station node and user equipment (UE) in time.

Design Features of the Second-Order Active Band-Pass Filters with Independent Adjustment of Critical Parameters

Abstract: Nowadays, it is urgent to develop a new generation of active RC filters, which allow for independent tuning of the critical parameters. This makes it easier to build new devices. The paper considers the generalized architecture of a new population of active RC band-pass filters (ARCFs) in which the independent adjustment of the critical parameters in the pass band is possible. As an example the equations for the transfer functions and their coefficients for two new ARCF modifications are given, which allow for the parametric synthesis of the definite design solutions. The results of modeling in the Micro-CAP program are discussed, confirming the advantages of the ARCFs of the considered family.

Evaluating the Frequency Limitations of Operational Amplifier RC Networks by the Dominant-Pole Technique

Abstract: A general computer-based technique is given for investigating the high-frequency performance of second-order active RC networks employing an arbitrary number of operational amplifiers. It uses the dominant-pole technique for finding deviations in Q and ω0 from their nominal values as a function of the gain bandwidth product of the operational amplifiers. The technique is applied to active RC circuits simulating a nonideal grounded inductance and curves are given for the highest usable frequency for permissible deviation in Q and ω0 for some typical circuits.

Asymptotic analysis of optimized waveform relaxation methods for RC circuits and RLCG transmission lines

Abstract: Waveform Relaxation (WR) methods are iterative methods to solve time-dependent problems and large systems of ordinary differential equations arising from large scale electronic circuits. These methods are based on partitioning large circuits into smaller sub-circuits, which are then solved separately for multiple time steps and the overall solution is obtained by iteration between sub-circuits. The slow convergence of these methods especially for large time windows led to the introduction of Optimized Waveform relaxation (OWR) methods, which are based on optimizing parameters. In this thesis, we study the application of these methods to infinite RC and RLCG type circuits. We consider both the overlapping and nonoverlapping WR methods and find the optimized parameters in the transmission conditions. We then developed a novel algorithm that is based on model order reduction techniques for the simplified analysis of OWR methods when applied to infinitely long electric circuits.

Patterned rotary parallel-plate capacitor for frequency up-conversion and RC circuit waveform conditioning

Abstract: This paper details a patterned electrostatic rotary capacitive plate design with high energy densities and provides a novel strategy for up-converting low frequency mechanical excitation sources. The rotating plates allow for output waveform signal conditioning in both control of frequency and waveform shaping. Particular advantages of the rotary plate design with patterned elements include the following: 1) simplicity of design, 2) frequency up-conversion, 3) output waveform signal conditioning, and 4) voltages appropriate for microelectronics. Applications include harvesting energy from environments with complex excitations, especially energy sources with inherently low-frequencies.

Monostable trigger of hybrid circuit and control method thereof

Abstract: The invention discloses a monostable trigger of a hybrid circuit and a control method thereof. A digital control circuit capable of accurately controlling time and outputting high and low levels is used for replacing a traditional RC circuit. Rectangular waves generated by the multivibrator are used as clock input of the counter. Frequency division can be carried out on a clock signal by utilizinga carry value preset by the counter. Pulse signals with different time lengths are output. The RS trigger turns over in response to the pulse signal. Therefore, the output level of the output end ofthe monostable trigger is changed, the monostable trigger can be converted between the transient state and the steady state, the pulse time of the rectangular wave can be accurately controlled by setting the carry value of the counter, and the transient state time of the monostable trigger can be accurately controlled.