Showing papers on "RLC circuit published in 2020"
TL;DR: The adaptive fault-tolerant control (FTC) problem is solved for a switched resistance–inductance–capacitance (RLC) circuit system and the unstable subsystems are taken into account in the frame of output constraint and unmeasurable states.
Abstract: In this article, the adaptive fault-tolerant control (FTC) problem is solved for a switched resistance–inductance–capacitance (RLC) circuit system. Due to the existence of faults which may lead to instability of subsystems, the innovation of this article is that the unstable subsystems are taken into account in the frame of output constraint and unmeasurable states. Obviously, there are not any unstable subsystems in unswitched systems. The unstable subsystems will involve many serious consequences and difficulties. Since the system states are unavailable, a switched state observer is designed. In addition, the fuzzy-logic systems (FLSs) are employed to approximate unknown internal dynamics in the controller design procedure. Then, the barrier Lyapunov function (BLF) is exploited to guarantee that the system output satisfy its constrained interval. Moreover, by using the average dwell-time method, all signals in the resulting systems are proofed to be bounded even when faults occur. Finally, the proposed strategy is carried out on the switched RLC circuit system to show the effectiveness and practicability.
162 citations
TL;DR: The theoretical analysis results show that DFIGs behave as an inductance in series with a negative resistance at the resonance point, whose interaction with wind farm side VSC (WFVSC) constitutes an equivalent RLC resonance circuit with negative resistance, and the oscillation tends to occur due to the negative damping.
Abstract: A new type of subsynchronous oscillation (SSO) has been observed recently in double-fed induction generator (DFIG)-based wind farm integrated via voltage source converter-based HVdc (VSC-HVdc) system. However, the mechanism of this emerging oscillation is not entirely understood. In this paper, the impedance models of DFIG with and without considering the phase-locked loop (PLL) dynamics are both derived. Then, the impedance-based simplified equivalent circuit of the multiple DFIGs interfaced with VSC-HVdc system is established. This model can be further represented as the RLC series resonance circuit to quantify the start-oscillating condition intuitively. The theoretical analysis results show that DFIGs behave as an inductance in series with a negative resistance at the resonance point, whose interaction with wind farm side VSC (WFVSC) (regard as a resistance–capacitance) constitutes an equivalent RLC resonance circuit with negative resistance. Therefore, the oscillation tends to occur due to the negative damping. In addition, the impact of various factors including number of grid-connected DFIG-wind turbines (WTs), wind speed, and parameters of PI controllers and PLL on the SSO characteristics is analyzed based on the proposed simplified model. Finally, the correctness of the theoretical analysis is validated by both the time-domain simulation and hardware-in-loop experiments.
137 citations
TL;DR: A mixed high-order compensation networks-based wireless power transfer system is proposed to generate multiple constant current outputs and current balance can be achieved, which is very suitable for driving multistring LEDs.
Abstract: Current imbalance in multistring light-emitting diodes (LEDs) is a critical issue. It may cause overcurrent in one or more LED strings, leading to rapid degradation. In this paper, a mixed high-order compensation networks-based wireless power transfer system is proposed to generate multiple constant current outputs. It is composed of an LCC resonant network in the transmitting side, a series resonant network, and multiple CLC resonant rectifiers in the receiving side. The CLC resonant rectifiers are connected in parallel to form multiple independent output channels, and each channel is then connected to an LED string. Based on the analysis of the T resonant circuit and the modeling of coupling coils, multiple constant output currents can be derived. As a result, current balance can be achieved, which is very suitable for driving multistring LEDs. The proposed system also offers a modular, scalable, and maintenance-free design, which can significantly reduce the construction cost and the control complexity. In addition, the inverter in the transmitting side can achieve zero phase angle. A laboratory prototype with dual independent output currents is built to verify the proposed method. The experimental results agree well with the theoretical analysis.
94 citations
TL;DR: In this article, a series $LC$ resonant converter is proposed for series-connected energy storage devices, namely, battery or super (or ultra)-capacitor cells.
Abstract: A novel cell voltage equalizer using a series $LC$ resonant converter is proposed for series-connected energy storage devices, namely, battery or super (or ultra)-capacitor cells. The proposed circuit is an active voltage equalization circuit for energy storage devices that is low cost, small in size, and equalizes the voltages quickly. Compared to the state-of-the-art solutions, the proposed series $LC$ resonant circuit eliminates the complexity of multiwinding transformers, and it can balance series-connected energy storage devices in a short time by transporting energy successively between the cells having highest voltage difference. The detailed circuit operation and theoretical analysis are provided. Simulation and experimental results are presented to demonstrate the voltage equalization process from an initial voltage difference of 527 mV to a final difference of 10 mV in 900 s for three series-connected supercapacitor cells.
38 citations
36 citations
TL;DR: This letter presents the self-oscillation phenomenon that is caused by the recovery processes of the diodes in a DBSS, and optimized designs for both the snubber circuit and the energy-absorbing circuit are proposed.
Abstract: At present, it is usually necessary to use fast recovery type diodes to cooperate with the fast switching actions of fully controlled devices such as insulated-gate bipolar transistors (IGBTs). However, the specific nature of the working conditions of the diode-bridge bidirectional solid-state switch (DBSS) provides an opportunity to apply standard recovery diodes for this purpose, which helps to reduce the cost of the bidirectional switch. This letter presents the self-oscillation phenomenon that is caused by the recovery processes of the diodes in a DBSS. Then, the recovery effects of these diodes in different topologies are analyzed from the perspective of the DBSS and optimized designs for both the snubber circuit and the energy-absorbing circuit are proposed. A 500-kV dc breaker is realized based on the proposed DBBS using the standard recovery diodes, which can work reliably with IGBTs, and the cost of the resulting dc circuit breakers is greatly reduced.
33 citations
TL;DR: The companion circuit method is employed to efficiently and readily solve the equivalent model of the dc grid to obtain post-fault branch currents and node voltages and improved accuracy, efficiency, adaptability, and flexibility are verified.
Abstract: DC short-circuit current calculation for the modular multilevel converter based multi-terminal direct current (MMC-MTDC) grid is critical and fundamental in equipment selection and protection setting. The existing MTDC grid short-circuit current calculation methods suffer from low efficiency, poor adaptability, and inflexibility. To address these issues, this paper proposes an efficient and general companion circuit-based method to estimate the short-circuit currents of asymmetric bipolar MTDC grids. First, an MMC is equivalent to an RLC series circuit in parallel with a time-dependent controlled current source. The equivalent model considers not only the discharge currents of the sub-module capacitors but also the ac in-feed current determined by MMC controllers. Then, the equivalent model for a bipolar MTDC grid with the dedicated metallic return is established by combing the equivalent MMC model with the lumped model of the dc transmission lines. Next, the companion circuit method is employed to efficiently and readily solve the equivalent model of the dc grid to obtain post-fault branch currents and node voltages. Both theoretical analyses and intensive tests on the CIGRE benchmark MTDC grid and Zhangbei bipolar MTDC grid verify the improved accuracy, efficiency, adaptability, and flexibility of the presented method.
31 citations
01 Jan 2020
TL;DR: The article discusses a graphical-analytical method for constructing the load characteristics of a three-element resonant circuit in the current stabilization mode, which represents the equation of an ellipse for the load mode in a dimensionless form.
Abstract: The article discusses a graphical-analytical method for constructing the load characteristics of a three-element resonant circuit in the current stabilization mode. The current stabilization mode is observed when compensating the negative section of the S-shaped characteristics of the parallel resonant circuit of the connected sequence with a linear inductance and with a linear capacitor characteristic. The equation of the load mode in a dimensionless form represents the equation of an ellipse, which makes it possible to construct the necessary characteristics of a three-element resonant circuit for various types of load.
31 citations
TL;DR: Excellent performance of the proposed method in terms of computation time and memory resource and providing the desired terahertz absorber characteristics shows that the method is promising as a design approach for sensing, imaging and filtering applications.
Abstract: In this paper, a simple, fast, and novel method for designing a tunable terahertz absorber with arbitrary central frequency and desired fractional bandwidth is presented. The proposed absorber consists of a single layer periodic array of graphene ribbons (PAGRs), placed a quarter wavelength from a metallic ground, separated by a dielectric material. An analytical circuit model of the terahertz absorber is used to obtain analytical expressions for the input impedance of the proposed device. Then, a simple expression for determining the value of capacitance and the resonance conditions of the RLC circuit is used to achieve a terahertz absorber with arbitrary central frequency and desired fractional bandwidth. The proposed method is applicable for the design of both narrowband and broadband absorbers, with only one layer of graphene ribbons. Also, the presented method is applicable for designing ultra-wideband absorbers using multiple layered PAGRs. Full-wave numerical simulation is performed to verify the accuracy and validity of the presented method. Excellent performance of the proposed method in terms of computation time and memory resource and providing the desired terahertz absorber characteristics shows that our method is promising as a design approach for sensing, imaging and filtering applications.
29 citations
TL;DR: In this article, the effect of undamped reflected wave and different cable lengths on both the inverter end and motor end is studied, and five different dv/dt filters are compared in terms of their impact on the switching losses, at the load, filter loss and damping time of the reflected wave.
Abstract: In voltage source inverter-based motor drives, the fast switching speeds of the power devices result in the reflected wave phenomenon. Besides the overvoltages at the motor end, there are overcurrents at the inverter end. The overvoltages increase stress on the motor and cable insulation, and the overcurrents affect the power devices. Wide bandgap (WBG) devices have lower switching losses and enable high switching frequencies. However, the reflected wave phenomenon is more pronounced in converters using WBG devices and could potentially increase the switching losses. This article presents a comprehensive analysis of the influence of the reflected wave phenomenon on the switching characteristics of SiC devices in motor drives. Notably, the effect of undamped reflected waves and different cable lengths on both the inverter end and motor end is studied. The analysis and experiments in this article uncover that, depending on the switching instance, the undamped reflected wave causes up to a 30% increase or up to a 15% decrease in the switching losses. A 12% reduction in the switching losses is observed with no cable to up to 20-m long cable. The last part of the article presents the design tradeoffs involved in designing a dv/dt filter. Five different dv/dt filters are compared in terms of their impact on the switching losses, dv/dt at the load, filter loss, and damping time of the reflected wave. The L filter and the RLC filter have around a 9% reduction in switching losses. The L filter suffers from increased damping time and higher reflected wave magnitude, making it unsuitable for high switching frequency applications. Overall, L // R filter offers the lowest filters losses with a 6% reduction in switching loss, making it more suitable for WBG devices-based high-speed motor drives.
29 citations
TL;DR: In this article, the effects of active and reactive power/current references on dq impedance characteristics of GCI with/without consideration of power control loop are investigated using complex space vectors and complex transfer functions.
Abstract: Oscillation phenomena of offshore wind power plant (OWPP) in a wide frequency range can be caused due to impedance interactions between grid-connected inverters (GCIs) and transmission cables. In this article, impedance model of GCI with outer power control loop, inner current control loop and phase-locked loop is first established in dq reference frame. The correctness is validated by frequency scanning method. Then, the effects of active and reactive power/current references on dq impedance characteristics of GCI with/without consideration of power control loop are investigated using complex space vectors and complex transfer functions. Furthermore, RLC circuit model of transmission cable considering frequency-dependent characteristics is also established for dq-domain IBSC. On the basis of them, it's found that low-frequency oscillation phenomena of OWPP under power control mode may occur if active power reference exceeds a certain threshold value, which can be mitigated by injecting a certain amount of negative reactive power. Impacts of PLL parameters, length of transmission cable and number of paralleled GCIs on required negative reactive power for low-frequency stabilization are further investigated. Both Matlab/Simulink-based simulation and OPAL-RT-based real-time verification are implemented in an OWPP with four permanent magnet synchronous generators to validate the correctness of the reactive power characteristic analysis results and the feasibility of mitigating low-frequency oscillation phenomena by negative reactive power injection.
01 Dec 2020
TL;DR: In this paper, the authors examined the stability of excited oscillations in resonant circuits in order to determine the possibility of their application to control thyristors in the function of changing the input voltage value.
Abstract: This article examines the stability of excited oscillations in resonant circuits in order to determine the possibility of their application to control thyristors in the function of changing the input voltage value. In resonant circuits connected to a voltage source with a low internal resistance, the occurrence of stable oscillations depends significantly on the value of the parameters of the circuit under consideration.
TL;DR: A modified hybrid dc breaker and a half-bridge modular multilevel converter (MMC) are employed to interrupt the dc fault current in a high-voltage direct current transmission system and the necessity to ultrafast mechanical switches is avoided.
Abstract: In this article, a modified hybrid dc breaker and a half-bridge modular multilevel converter (MMC) are employed to interrupt the dc fault current in a high-voltage direct current transmission system. In the hybrid dc breaker, parallel to the main branch, a series connection of an energy-absorbing capacitor and a Thyristor stack is employed. When a dc fault current is recognized, the Thyristor stack is triggered and the load commutation switch in the main branch is turned off . In addition, in the fault clearing state, the MMC is programmed to generate zero voltages at all arms. Using this mechanism, a second-order RLC circuit with zero input is formed, and the fault current is cleared in a very short time. A freewheeling path is provided to bypass the dc line when the equivalent inductance seen from the dc line is large. In contrast to conventional approaches, the peak of dc fault current is limited to a specific limit and the necessity to ultrafast mechanical switches is avoided. In addition, the amplitude of arms currents and corresponding insulated-gate bipolar transistors are kept in the safe operating area. A detailed circuit analysis of the new method is given and design formulas are extracted. Simulation results are provided in PSCAD/EMTDC environment, and experimental results are presented for a scaled-down prototype.
TL;DR: The measurement results show that the proposed topology could realize a broadband high-efficiency rectifier for ambient RF EH, and the measured results were basically consistent with the simulation results.
Abstract: In this letter, a compact broadband high-efficiency RF rectifier is presented for ambient RF energy harvesting (EH). A novel impedance matching network with an additional quarter-wavelength short-circuited stub was designed to achieve broadband impedance matching. After the branch was added, the parallel resonance point on track $S_{11}$ did not move, and the remaining points were compressed. The measurement results show that the proposed topology could realize a broadband high-efficiency rectifier for ambient RF EH, and the measured results were basically consistent with the simulation results. The measured efficiency is as high as 71.5% for an input power level of 8 dBm. A 1–2.4 GHz wide frequency band with an efficiency above 50% is achieved for an input power level of 5 dBm with a terminal load of 1.6 $\text{k}\Omega $ . Moreover, the circuit had wide dynamic input power characteristics, whose measured values remained above 50% with an input power of 3–14 dBm.
TL;DR: In this article, the authors proposed a tri-band left-handed meta-atom with high effective medium ratio, which is applicable for microwave-based communication applications and analyzed its properties.
Abstract: This paper represents a tri-band left-handed meta-atom with high effective medium ratio, which is applicable for tri-band microwave based communication applications. The proposed meta-atom consists of modified complementary split ring resonator (CSRR) with two pi shaped metal strip loaded in the inner side. It shows the behavior of negative permeability and permittivity at 2.85 GHz, 4.83 GHz, 8.39 GHz, and 11.42 GHz resonance frequencies and extracted the double negative (DNG) metamaterial properties. The designed meta-atom dimension is 0.076 λ × 0.076 λ at lower resonance frequency. To develop and analyze the offered meta-atom, the electromagnetic (EM) simulator CST Microwave Studio and MATLAB software were used. The equivalent circuit with RLC components of the proposed metamaterial unit cell is also investigated through ADS simulator and comparing S parameter (transmission coefficients) results with CST results. Analysis and comparison have been carried out with different configurations, such as various design structures, distinct substrate, changing the gap of the splits, and various array measures. All the array configurations proved that the frequency of operation is in the S-, C-, and X-bands. The designed meta-atom has double negative regions of 2.89–2.96 GHz, 4.84–4.99 GHz, 8.42–8.49 GHz, and 11.43–12.32 GHz, with the regions of effective negative refractive index 2.85–3.09 GHz, 4.83–5.36 GHz, 8.40–8.57 GHz, and 11.40–12.55 GHz, respectively. The effective medium ratio is 13.16; this implies that the proposed miniaturized meta-atom design is efficient and compact. The scattering parameter dimension of the meta-atom promising for the microwave based applications at S-, C-, and X-bands.
TL;DR: The coupled-mode theory model of the proposed WPT system is established, and the impact of different loads and orders on transfer characteristics is explored, demonstrating that the proposed system can achieve constant current output that is independent of load.
Abstract: Wireless power transfer (WPT) using magnetic-coupling resonant has been proved to be a promising transmission method. At present, most of the existing resonant WPT systems adopt integer-order inductors and capacitors. In fact, in addition to integer-order components, there also exists fractional-order inductors and capacitors, which possess richer characteristics than integral-order inductors and capacitors. However, there are few studies on the application of fractional-order components in resonant WPT system. Therefore, this paper proposes a fractional-order resonant WPT system, which is based on a fractional-order resonant circuit only incorporating a fractional-order capacitor. The coupled-mode theory model of the proposed WPT system is established, and the impact of different loads and orders on transfer characteristics is explored. The theoretical analysis demonstrates that the proposed system can achieve constant current output that is independent of load, just by choosing appropriate parameters of the fractional-order capacitor. Finally, an experimental prototype of the fractional-order resonant WPT system is built, and the experiment results verify the correctness of the theoretical analysis.
TL;DR: In this article, a combination of pulse frequency modulation and phase shift modulation is used to control a high-power full-bridge unidirectional resonant LLC solid-state transformer (SST) for a wide load range.
Abstract: In this study, analysis and control of a highly efficient, high-power full-bridge unidirectional resonant LLC solid-state transformer (SST) are discussed. A combination of pulse frequency modulation and phase-shift modulation is utilized to control this resonant converter for a wide load range. The converter is designed to maintain soft switching by using a resonant circuit to minimize the switching loss of the high-frequency converter. Zero-voltage-switching (ZVS) is achieved for the H-bridge converter. The ZVS boundary for the proposed combined control method is also analyzed in detail. The experimental setup for the suggested configuration was implemented, and the performance of the proposed control scheme and resonant LLC SST have been verified with test results. The proposed combined control scheme improves control performance. The obtained results show that, the proposed system can regulate output voltage and maintain soft switching in a wide range of load. Thus, the efficiency of the system is improved and an efficiency of 97.18% is achieved.
TL;DR: In this paper, a new bidirectional dc/dc converter topology based on a hybrid string-inverter/rectifier structure with an isolated CLLC resonant circuit is presented for energy storage applications.
Abstract: In this article, a new bidirectional dc/dc converter topology based on a hybrid string-inverter/rectifier structure with an isolated CLLC resonant circuit is presented for energy storage applications. In this topology, a novel inverter/rectifier leg is presented that enables this circuit to operate in rectifying mode with much lower voltage ripple compared to the standard four-switch string rectifier circuit with the same capacitive filter. Compared to the dual-active-bridge circuit structure, the proposed inverter/rectifier leg is able to reduce the number of high-voltage switches required. A CLLC resonant circuit is employed to step-up/down the dc voltage levels. The operating principles of the proposed converter are discussed in this article. Silicon Carbide switches are used in both legs of the proposed converter, with zero-voltage switching turn- on and zero-current switching (ZCS) turn- off realized for all switches, whereas ZCS turn- on and off are achieved for all diodes. Simulation and experimental results are provided on a 1-kW, 100-kHz, 400-V/700-V converter system to highlight the merits of the proposed converter. Experimental results demonstrated that an efficiency of close to 97% is achieved in the proposed converter in both boost mode and buck mode at the full-load condition.
TL;DR: In this article, a self-adapting synchronized-switch harvesting (SA-SSH) interface circuit was proposed to extract energy from vibration-based piezoelectric energy harvesters (PEHs).
Abstract: This paper presents a self-adapting synchronized-switch harvesting (SA-SSH) interface circuit to extract energy from vibration-based piezoelectric energy harvesters (PEHs). The implemented circuit utilizes a novel switching technique to recycle optimum amount of harvested charge on piezoelectric capacitance to strengthen the damping force, and simultaneously achieve load-independent energy extraction with a single inductor. Charge recycling is realized by adjusting extraction time, and optimized through a maximum power point tracker based on charge-flipping dissipation. The circuit has been implemented using 180 nm HV CMOS technology with 0.9 × 0.6 mm2 active area. Self-adapting SSH circuit has been validated with both macro-scaled and MEMS PEHs with different inductor values. The interface circuit provides maximum energy extraction for the full storage voltage range of 1.8–3.7 V. The implementation harnesses have 500% more power compared to an ideal full-bridge rectifier, and output 3.4 μW for 2.24 V peak-to-peak open-circuit piezoelectric voltage from MEMS PEH excited at its resonant frequency.
TL;DR: In this paper, the design of two dual-band graphene-based absorbers for terahertz frequencies is presented based on the excitation of a specific plasmon polariton of the graphene patterned array at each resonance band.
Abstract: This article presents the design of two dual-band graphene-based absorbers for terahertz frequencies. The absorbers are composed of two-dimensional (2D) arrays of ribbons and disks printed on a ground plane backed dielectric spacer. The design is based on the excitation of a specific plasmon polariton of the graphene patterned array at each resonance band. An analytical circuit model is used to derive closed-form relations for the geometrical parameters of the absorber and graphene parameters. The graphene patterned array appears as a surface admittance made of an infinite parallel array of series RLC branches. Each branch is equivalent to a graphene plasmon polariton (GPP) providing a distinct resonance mode. The design procedure is based on selectively exciting the first two GPPs. This means that two of the parallel RLC branches are selectively used in the circuit model analysis. The results obtained using the analytical solution are compared with the full-wave simulations in HFSS. The agreement between the results validates the developed design method.
TL;DR: In the case of two-port configuration, in addition to the improvement in insertion loss, a lower noise figure can be theoretically achieved as well, and the theoretical analysis is verified in simulation and measurement.
Abstract: This paper reviews the possibility of adding an active circuit that implements a small signal negative resistor, to the baseband portion of the N-path filter circuit, in order to compensate for losses that are caused due to harmonic products and other parasitic effects. By adding an active circuit inside the baseband part insertion loss can be eliminated reciprocally. Interestingly, in the case of two-port configuration, in addition to the improvement in insertion loss, a lower noise figure can be theoretically achieved as well. The introduction of the negative resistance is analyzed using linear periodically time-variant theory and linear time invariant approximation. The theoretical analysis is verified in simulation and measurement. The circuit implementation consists of a two-port N-path filter, implemented in a 65-nm CMOS process, with a PMOS cross-coupled pair serving as the negative differential resistor. We achieve $\sim 3.5~dB$ insertion loss improvement at the expense of $0.64~mW$ power addition, at the frequency range of 0.75–2 GHz.
TL;DR: The experimental results proved the correctness of the basic idea and showed stable self-oscillations with a tuning range from 1:2 to 1:3 and the influence of NIC dispersion, non-linearity, and antenna type on the system performances is discussed and appropriate design guidelines are given.
Abstract: The concept of a self-oscillating non-Foster unit cell, intended for use in future active metasurfaces, is introduced. It is based on two orthogonally polarized small antennas connected via a negative impedance converter (NIC). An NIC converts the admittance of the first antenna into a negative admittance, canceling the admittance of the second antenna within a theoretically infinite bandwidth. This system behaves as a special kind of a nearly perfectly matched small active antenna that supports oscillations at every frequency within NIC’s operating bandwidth. Frequency tuning is achieved either by inclusion of a resonant circuit or by injection locking from an external source. The influence of NIC dispersion, non-linearity, and antenna type on the system performances is discussed, and appropriate design guidelines are given. Several scaled experimental demonstrators of non-Foster self-oscillating unit cell, operating in lower RF range, were designed, manufactured, and tested. The experimental results proved the correctness of the basic idea and showed stable self-oscillations with a tuning range from 1:2 to 1:3.
TL;DR: A hybrid self-powered synchronous electric charge extraction (HSP-SECE) interface circuit based on double stack resonance is presented in this paper and simulation and experimental results show the superiority of the HSP- SECE circuit.
Abstract: A hybrid self-powered synchronous electric charge extraction (HSP-SECE) interface circuit based on double stack resonance is presented in this paper. The proposed HSP-SECE interface circuit can simultaneously extract energy from piezoelectric transducer (PZT) and thermoelectric generator (TEG) when the peak open-circuit voltage of the PZT is detected by passive peak detector. The output power of the proposed interface circuit can reach three times of that of full-bridge rectifier circuit at the maximum power point, and the maximum efficiency of harvesting thermoelectric energy can reach 76% at 200 mV of the open-circuit voltage of the TEG. The simulation and experimental results show the superiority of the HSP-SECE circuit.
TL;DR: In this paper, a novel oscillation wave test system (OWTS) was proposed to detect the partial discharge (PD) of mounting defects in power cable insulation, where a charging capacitor was added to the circuit topology based on the traditional OWTS.
Abstract: This paper presents a novel oscillation wave test system (OWTS) to detect the partial discharge (PD) of mounting defects in power cable insulation. In the proposed system, a charging capacitor is added to the circuit topology based on the traditional OWTS. The charging capacitor is charged to the desired voltage by a high-voltage DC power source. After the charging process, the test cable sample is charged by the capacitor. The resonant circuit is formed by the charging capacitor, the test cable, and the resonant reactor to create an oscillating decay voltage. With this novel method, no space charge is injected into the cable insulation. The effect of the charging capacitance on the charging efficiency is calculated with the Multisim software. This paper describes the working principle and the assembly of a laboratory prototype for the PD detection of a 500 m cable circuit. The test results show the feasibility of the novel OWTS method.
TL;DR: Chaos-based encryption application to protect electrocardiogram signals for secure transmission of medical information is performed using the proposed oscillator in chaotic regime and the original ECG signal is successfully decrypted from noisy ECG signals.
Abstract: An autonomous passive–active integrators oscillator with anti-parallel diodes is proposed and analysed in this paper. It consists of anti-parallel diodes and two main blocks: A second-order passive RLC integrator and a first-order active RC integrator. The existence of two Hopf bifurcations is established during the stability analysis of the unique equilibrium point. For a suitable choice of the circuit parameters, the proposed oscillator can generate periodic oscillations, one-scroll, bistable chaotic attractors and antimonotonicity. The electronic circuit realization of the proposed oscillator is carried out to confirm results found during the numerical simulations. A good qualitative agreement is illustrated between the numerical simulations and experimental results. In addition, chaos-based encryption application to protect electrocardiogram (ECG) signals for secure transmission of medical information is performed using the proposed oscillator in chaotic regime. The ECG signals are successfully encrypted and the original ECG signal is successfully decrypted from noisy ECG signals.
TL;DR: This paper presents the design and implementation of a high-frequency/very high frequency (VHF) multiresonant gate drive circuit that can reduce the long start-up time required in a self-oscillating resonant gateDrive circuit and utilize the fast transient capability of VHF converters better.
Abstract: This paper presents the design and implementation of a high-frequency/very high frequency (VHF) multiresonant gate drive circuit. The design procedure outlined here is greatly simplified compared with other VHF self-oscillating multiresonant gate drivers presented in previous works. The proposed circuit can reduce the long start-up time required in a self-oscillating resonant gate drive circuit and utilize the fast transient capability of VHF converters better. We demonstrate a prototype resonant gate driver, which reduces up to 60% of the gate-driving power in a 20-MHz 32-W Class-E power amplifier using a Si MOSFET. The proposed technique could also drive a high-voltage rated SiC MOSFET at 30 MHz with a slew rate of 2.5 V/ns at the gate, while an integrated hard-switching gate driver only provides a slew rate of 1.8-V/ns and is five times less efficient than the proposed resonant gate driver.
TL;DR: In this paper, the authors presented a new design of a fifth order bandpass waveguide filter with Chebyshev response which operates in the X-band at 10 GHz center frequency.
Abstract: This paper presents a new design of a fifth order bandpass waveguide filter with Chebyshev response which operates in the X-band at 10 GHz center frequency. By using a complementary split ring resonator (CSRR) upper and lower sections that are placed on the same transverse plane and are not on the same parallel line, CSRR sections are shifted from each other. A simple model of lumped elements RLC is introduced and calculated as well. The model of the proposed bandpass waveguide filter is synthesized and designed by using computer simulation technology (CST). Hereafter, by selecting proper physical parameters and optimizing the overall CSRR geometrical dimensions by taking into consideration the coupling effect between resonators, a shortened length of the overall filter, and a wider bandwidth over the conventional one are obtained. As a result, the proposed filter is compared with the conventional bandpass waveguide filter that is coupled by inductive irises with Chebyshev response, in addition to other studies that have used the metamaterial technique. The proposed filter reduces the overall physical length by 31 % and enhances the bandwidth up to 37.5 % .
TL;DR: In this article, an electrical RLC circuit in two-dimensional spaces described by a fractional-order derivative is considered and the qualitative properties of the proposed model are analyzed. And the solution to the solution is suggested.
Abstract: We consider an electrical RLC circuit in two-dimensional spaces described by a fractional-order derivative. We propose the qualitative properties of the proposed model. We analyze the local asymptotic stability and the global asymptotic stability for the trivial equilibrium point for the electrical RLC circuit. We suggest the solution to the proposed model too. In our investigation, we consider the Caputo-Liouville fractional-order derivative. We use the characteristic matrix for the electrical RLC circuit model to analyze the local asymptotic stability of the trivial equilibrium point. For global asymptotic stability, we use the Lyapunov function method by constructing a Lyapunov function.
TL;DR: In this article, a passive resonant level shifter that can suppress the effect of the crosstalk and deliver a low off-state gate-source voltage to reduce the forward voltage drop of the body diode of SiC mosfet s is presented.
Abstract: Due to the presence of parasitic elements in switching devices and circuit realization, crosstalk phenomenon in bridge-leg configurations is unavoidable. A passive resonant level shifter that can suppress the effect of the crosstalk and deliver a low off -state gate-source voltage to reduce the forward voltage drop of the body diode of SiC mosfet s is presented. The circuit is composed of two parts. The first one is a resistor-capacitor-diode (RCD) level shifter that delivers a static negative off-state gate-source voltage to the mosfet s. The voltage level is designed to be close to zero, so that the forward voltage drop of the body diode is lowered. The second one is a series resonant tank circuit. It generates short voltage pulses to counteract the voltage pulses caused by the crosstalk. The gate-source voltage can then be maintained at a level below the threshold voltage of the mosfet s. The proposed level shifter does not require any active devices or additional supply. It can be applied readily to commercially available gate drivers. A passive resonant level shifter module for four SiC mosfet s in a 1-kW H-bridge inverter has been built and evaluated. Detailed performance comparison with the RCD level shifter will be given.
TL;DR: In this paper, a two-stage resonance effect control circuit utilizing resonant effects and an automatic capacitance switching method was proposed to enhance the magnetic field with respect to the desired operating frequency in a wide range.
Abstract: This article presents a novel design and a control methodology for an electromagnetic actuation (EMA) system that can generate a high-frequency and high-powered electromagnetic field for enhanced electromagnetic torque and force. The proposed system consists of a two-stage resonance effect control circuit utilizing resonant effects and an automatic capacitance switching method matching the desired frequency. The first resonant effect control stage, which is called the series resonance, is comprised of various capacitors connected with the EMA system and is designed to compensate for rapid impedance change and phase delay. The second resonant effect control stage, which is called the current-amplified resonant circuit, is integrated to amplify coil currents for a high-frequency operation. In addition, the automatically controllable continuous capacitance switching method is proposed to enhance the magnetic field with respect to the desired operating frequency in a wide range. Finally, the resonance control system is applied to the conventional EMA system. In-vitro experiments were conducted on three-dimensional locomotion and a drilling motion control for a helical-shaped microrobot. Both simulation and experimental results showed a significant improvement in the microrobot locomotion ability, speed (235%), and driving force (900%) with respect to the conventional design. The developed EMA control circuit and algorithm can magnify the input current nearly twice the conventional EMA system and extend the operating frequency to a maximum of 370 Hz.