Filter Capacitor Research Articles

Design a H-bridge low ripple and high bandwidth air core magnet corrector power supply in NSRRC

This paper is the study of a low-current-ripple and high-bandwidth corrector power supply. The main circuit of this power supply is using a full bridge (H-bridge) structure, and the output current through the high-precision direct current current transducers (DCCT) to transfer the reference voltage to the controller. Previous TPS corrector power supply had a 4.7 kHz current bandwidth, and its output current ripple was 100 μA. Such current ripple and bandwidth do not satisfy the requirements of a rapidly orbiting feedback system of air core loading. Therefore, our research team designed a novel prototype power supply with a high bandwidth (more than 10 kHz) and low output current ripple (less than 10 μA) which was developed via a novel topology circuit. The operation frequency of the main power switch's n-type metal-oxide-semiconductor logic of this novel circuit is increased to 245 kHz. Moreover, the output results of the filter inductor and filter capacitor are modified to 80 μH and 2.46 μF, respectively. The prototype power supply bandwidth reached 10.546 kHz and increase of 124% and its output current ripple was lowered below than 5 μA. The properties of this corrector power supply are very important for the beam correction in storage rings. Finally, A circuit with an input voltage of 48 V, a maximum output current of 10 A, and an output power of 400 W is tested in a laboratory to verify the performance of the developed corrector for the National Synchrotron Radiation Research Center.

The Effects of Filter Capacitors on Cable Ripple at Different Sections of the Wind Farm Based Multi-Terminal DC System

In most DC power systems, power electronic devices can introduce ripple content into the DC grid, where large input ripple currents on the DC link can have a negative influence. Under these circumstances, DC side filters play an important role in the reduction of ripple content. In this paper, based on a full detailed closed loop model of the entire offshore wind farm multi-terminal DC network, the effect of filter capacitors connected at different sections of the system on the limitation of the AC ripple content, particularly in the DC cables, is studied. In contrast to other work on HVDC for offshore wind, where simplified or equivalent circuits are mainly used while concentrating on the power and control system, this study can be regarded as the specific study of filter capacitors operating within a detailed system model. Utilising the advantages of PLECS, which is a highly effective tool in the simulation of power electronic circuits, no small-signal or simplified equivalent models are used in the system, and the entire study is based on detailed and accurate models of the semiconductor elements and transformers, which help to provide more realistic simulation results and a better understanding of the system. Another novel point in this paper is a new concept, relative losses, which is proposed to simplify extensively the calculation of losses in this research. Finally, the size of the filter capacitors at different sections of the system under different situations is suggested.

Low-Voltage GaN FETs in Motor Control Application; Issues and Advantages: A Review

The efficiency and power density improvement of power switching converters play a crucial role in energy conversion. In the field of motor control, this requires an increase in the converter switching frequency together with a reduction in the switching legs’ dead time. This target turns out to be complex when using pure silicon switch technologies. Gallium Nitride (GaN) devices have appeared in the switching device arena in recent years and feature much more favorable static and dynamic characteristics compared to pure silicon devices. In the field of motion control, there is a growing use of GaN devices, especially in low voltage applications. This paper provides guidelines for designers on the optimal use of GaN FETs in motor control applications, identifying the advantages and discussing the main issues. In this work, primarily an experimental evaluation of GaN FETs in a low voltage electrical drive is carried out. The experimental investigation is obtained through two different experimental boards to highlight the switching legs’ behavior in several operative conditions and different implementations. In this evaluative approach, the main GaN FETs’ technological aspects and issues are recalled and consequently linked to motion control requirements. The device’s fast switching transients combined with reduced direct resistance contribute to decreased power losses. Thus, in GaN FETs, a high switching frequency with a strong decrease in dead time is achievable. The reduced dead time impact on power loss management and improvement of output waveforms quality is analyzed and discussed in this paper. Furthermore, input filter capacitor design matters correlated with increasing switching frequency are pointed out. Finally, the voltage transients slope effect (dv/dt) is considered and correlated with low voltage motor drives requirements.

ОДНОФАЗНИЙ ГІБРИДНИЙ ФІЛЬТР ДЛЯ ДЕЦЕНТРАЛІЗОВАНИХ СИСТЕМ ЕЛЕКТРОПОСТАЧАННЯ

The analysis of the single-phase hybrid filter of network current harmonics, which can be applied in the decentralized power system, was carried out. Mathematical modeling of such a system that feeds a bridge rectifier with a capacitive filter and the 10 kW active load was performed. A comparison of current spectrograms and current diagrams of different configurations of a hybrid filter implemented in the active part on the basis of an active corrector of the parallel type, and in the passive part - a broadband LMC filter with an additional winding Ld was carried out. The maximum current deviations from the shape of the first harmonic of the current consumption for different structures of the passive filter were determined, which is decisive for the calculation of the power part of the active filter. The installed power of the active filter was calculated, the harmonic coefficients of the current consumption of the power supply network were obtained. Ref. 11, fig. 5, table.

Feedback Linearization-Based Control Strategy for Interlinking Inverters of Hybrid AC/DC Microgrids with Seamless Operation Mode Transition

This study proposes an advanced control scheme for the interlinking inverters of the hybrid AC/DC microgrids, which facilitates a seamless transition between grid-connected and stand-alone/islanding modes for the microgrid. Due to a nonlinear relationship between the terminal voltages of the voltage-source inverter (VSI) interfacing through inductor–capacitor (LC) filters with the grid voltages and currents, a feedback linearization technique (FLT) is employed to control the interlinking VSI under both grid-connected and islanding operations. The FLT-based current controllers are applied in the grid-connected mode, in which they adjust the power exchange between the DC and AC subgrids and mitigate the distortion of the grid currents produced by nonlinear loads. Under the stand-alone operation, the AC bus voltages are directly regulated by the FLT-voltage controllers of the interlinking VSI. In order to reduce the inrush currents and voltage overshot at the instant of mode switching, the FLT-based controllers are performed all the time regardless of the operating modes, where the voltage references for the VSI are not changed abruptly. The control performance of the VSI is highly satisfactory with low-transient overshoot values of the voltages and currents and low total harmonic distortion (THD) values of the grid currents and AC bus voltages are about 3.5% and 2.7%, respectively, under the nonlinear load condition. The validity of the new control strategy is verified by the simulation work, which investigates the operation of a hybrid AC/DC microgrid.

New bidirectional step-up DC-DC converter derived from buck- boost DC-DC converter

<span lang="EN-US">This paper proposes a new bidirectional step-up DC-DC converter, namely modified buck-boost DC-DC converter. The proposed DC-DC converter was derived from the conventional buck-boost DC-DC converter. Output voltage expression of the proposed converter was derived by considering the voltage drops across inductors and switching devices. The results have shown that with the same parameter of input LC filter, proposed DC-DC converter has lower conduction losses. Moreover, the proposed DC-DC converter has lower rated voltage of filter capacitor than the conventional boost DC-DC converter which lead to cost efficiency. Finally, a scaled-down prototype of laboratory experiment was used to verify its theoretical analysis.</span>

A Resistorless Low-Power Voltage Reference Based on Mutual Temperature Cancellation of VT and VTH

In this paper, a novel resistorless CMOS voltage reference with a sub-one-volt power supply is proposed and simulated in 90 nm CMOS technology. The thermal voltage obtained from ∆VBE is converted into a current (I) proportional to the square of temperature (T2) using a deep triode MOSFET as a resistor. A linear positive temperature coefficient part of the circuit is built by applying this current through a diode-connected MOSFET. VTH is also used as a negative temperature coefficient part. The reference voltage is obtained from the proper combination of these two parts. The proposed circuit is designed in the sub-threshold region to reduce power consumption. Moreover, using bulk biasing and an array of MOSFETs, a trimming circuit is adopted to compensate for the process-related reference voltage variation. The nominal output voltage reference is about 0.5 V with a temperature coefficient of 25.4 ppm/oC over a temperature range of 0 oC to 100 oC. The power supply noise attenuation of 87.5 dB is achieved without any filtering capacitor below 23 Hz at 1 V of Vdd.

Electrospun Polymer-Derived Carbyne Supercapacitor for Alternating Current Line Filtering.

The filtering device is a vital component of electronic goods that rectifies ripples which occur upon converting alternating current (AC) to direct current (DC) and attenuates high-frequency noise during switching or voltage declines. Classical filtering devices suffer from low performance metrics and are bulky, limiting their use in modern electronic devices. The fabrication process of electrode materials for high-frequency symmetric supercapacitor (HFSSC) is complicated, hindering commercialization. Herein, for the first time, the design of a high-performance stand-alone carbyne film comprised of sp/sp2 -hybridized carbon as an electrode for AC filtering under a wide frequency range is reported. The carbyne film as HFSSC shows the ideal capacitive behavior at ultrahigh scan rate of 10000Vs-1 with excellent linearity which is top among the reported AC line filter capacitor. The carbyne HFSSC exhibits a high energy density of 703.25µFV2 cm-2 at 120Hz, which is superior to that of current commercial electrolytic filters and many reported AC line supercapacitors. As a proof of concept, a carbyne device is implemented in a real time AC to DC adaptor that demonstrates excellent filtering performance at high frequencies.

Multilayer Model Predictive Control for a Voltage Mode Digital Power Amplifier

The application of the finite control set model predictive control to cascaded inverters is severely limited by its computational complexity. In this paper, a load observer based multilayer model predictive control is proposed for the voltage mode digital power amplifier employing cascaded full-bridge neutral point clamped inverter, which can avoid the use of load current sensor and greatly reduce the controller computation without affecting its dynamic performance. The discrete mathematical model of the voltage mode digital power amplifier employing cascaded full-bridge neutral point clamped inverter is established with filter inductor current and filter capacitor voltage as state variables. A load current observer is designed based on this to avoid the use of load current observer. Based on the discrete model and the observed load current, the upper layer of the multilayer model predictive control determines the optimal level that minimizes the cost function. The middle layer allocates the optimal level to each submodule in order to achieve capacitor voltage balancing. The lower layer determines the switching state of each submodule in order to reduce switching actions. Finally, the experimental results based on the designed nine-level prototype show that the develop multilayer model predictive control lead to acceptable steady state, dynamic and robust performance, with only 1.37% of the run time of the traditional model predictive control.

Resonance suppression of LCL filter for shunt active power filter via active damper

Resonance damping of LCL filter has become a crucial concern in the operation of shunt active filter inverters due to its wide control bandwidth. To address the challenges of the resonance issue, this paper proposes a novel damping method for SAPF with an LCL filter to reduce the damping losses without affecting control of SAPF. The proposed approach is based on an auxiliary converter that is connected to the filter capacitor in series. In the auxiliary converter, the resonance current is detected and injected by inverse as a controlled voltage. The stability of the proposed method is carried out by bode diagrams and compared with the conventional method. The performance of the proposed method has been validated under different cases by implementing a laboratory setup. The effectiveness of the proposed method has been validated through the theoretical and experimental results. The switching harmonic components are attenuated by 215 dB and 70 dB ratios at the 10 kHz and 20 kHz via the proposed method. Furthermore, the damping power losses are 1.9% and 0.9% for the conventional method and the proposed method, respectively. As a result, the proposed method has better switching harmonic mitigation with 1% lower damping power losses than the conventional method.

Noise and sensitivity comparison for different BP filter designs

In this paper, the analysis of noise and sensitivity for different BP filter designs is observed. Calculation of the voltage noise spectral density, root mean square (RMS) value of the noise voltage, Schoeffler sensitivity and the multi-parameter sensitivity is done for the simply designed (SD) active RC, noise and sensitivity optimized (NO and SO) active RC, operational transconductance amplifiers (OTA-C) and switched capacitor (SC) filter designs. This is observed for the fourth-order Chebyshev band-pass filter, with central frequency fc = 4 kHz, bandwidth 1 kHz and pass-band ripple αmax = −0.1 dB. Cascade of two second-order sections is used for fulfilment realization of all four observing designs. Programming tools, such as MATLAB and SPICE (LTspice), are also used for the analyses. Highlights We used three different designs and optimization (noise and sensitivity) procedure for design and optimize the fourth-order Chebyshev band-pass filter Our results suggest which design is best to use for improving noise and sensitivity of this filter MATLAB and SPICE software were used for calculations and simulations of different band-pass filter designs and analysis of noise and sensitivity

A Method for Designing and Optimizing the Electrical Parameters of Dynamic Tuning Passive Filter

Power electronics-based apparatuses absorb non-sinusoidal currents. These are considered non-linear and non-symmetrical loads for the power grid, and they generate a harmonic current. The dynamic tuning passive filter (DTPF) is one of the best solutions for improving power quality and filtering out harmonic currents to get a symmetrical current waveform. The electrical parameters of DTPF can influence its absorbing harmonic current, tuning performance, and cost. In this paper, a method for designing and optimizing the electrical parameters of dynamic tuning passive filter is proposed in order to improve the effectiveness of DTPF and the symmetry level of the power source. First, according to the characteristics of the harmonic source, the design technical indicators of DTPF, and its topology, the design procedure for the electrical parameters of DTPF is proposed. Second, based on detailed analysis of the test results, the range of the harmonic current absorption coefficient is determined. Third, the range of the relationship coefficient is determined by analyzing the impact of the filter capacitor’s capacity on the filter performance. Fourth, the calculation method for the electrical parameters of DTPF is devised. Finally, the validity of this method is verified by several engineering cases, and the electrical parameters of the filter capacitor and electromagnetic coupling reactance converter (ECRC) under the lowest total cost are simulated and optimized. Our approach can optimize the electrical parameters of DTPF and improve the harmonic suppression effectiveness, thus leading to a more symmetrical waveform and successfully avoiding power grid problems. The research results of this study not only provide a basis for the design of ECRC, but also lay a foundation for the machining DTPF.

Auto-Zeroing Static Phase Offset in DLLs Using a Digitally Programmable Sensing Circuit

This brief presents a static phase offset (SPO) reduction technique through auto-zeroing in a delay-locked loop (DLL). We propose a self-calibrated, digitally programmable, sensing circuit that can measure both the polarity and the magnitude of the SPO. The SPO is suppressed by tuning a pair of digital-to-time converters (DTCs) at the input of the phase frequency detector (PFD). The proposed technique enables run-time background calibration and can suppress the SPO caused by artifacts from the PFD, charge pump, and loop filter capacitor. Monte Carlo simulation results show that the SPO in a conventional DLL implementation improves from 12.92 ps to 0.90 ps when the proposed auto-zeroing technique is employed.

Quasi Power Factor Correction for High Efficient AC/DC Converter

Harmonic pollution and low power factor in power systems caused by power converters have been of great concern. To overcome these problems several converter topologies using advanced semiconductor devices and control schemes have been proposed. This investigation is to identify a low cost, small size, efficient and reliable ac to dc converter to meet the input performance index of UPS. The performance of single phase and three phase ac to dc converter along with various control techniques are studied and compared. This project presents a novel ac/dc converter based on a quasi-active power factor correction (PFC) scheme. In the proposed circuit, the power factor is improved by using an auxiliary winding coupled to the transformer of a cascade dc/dc fly back converter. The auxiliary winding is placed between the input rectifier and the lowfrequency filter capacitor to serve as a magnetic switch to drive an input inductor. Since the dc/dc converter is operated at high-switching frequency, the auxiliary windings produce a high frequency pulsating source such that the input current conduction angle is significantly lengthened and the input current harmonics is reduced. Since the use of a single inductor, the cost z reduced a lot and the efficiency of the system is improved. The power factor is maintained constant by using a buffer capacitor in parallel to the system for compensating the inductive components. It eliminates the use of active switch and control circuit for PFC, which results in lower cost and higher efficiency. Finally an R- load is applied and simulation results are presented

Design of Switched Capacitor Filter with Transmission Gate Switches

A filter is a circuit that allows some frequencies to pass through it, while attenuating others frequencies. Generally, Filter can be designed using components like resistors and capacitors. In VLSI Technology Resistors with large values cannot be inserted on to a chip so easily. An alternate circuit can be replaced in place of resistor (i.e., Switched capacitor). In this paper we are designing a low pass filter using the switched capacitor and comparator,[4] the switched capacitor constitutes two switches and a capacitor, op-amp is been used as comparator. The switches can be either Nmos or Pmos Transistors or Transmission gate, they perform the switching action when clock driver o/p signal is given to gate terminal of these transistors. Frequency response of low pass filter using Pass Transistors and Transmission gate is observed and cutoff frequency is been calculated in each case, it may be either by pass transistors or transmission gates in tool named cadence virtuoso. Designing of low pass filter is done by 180nm technology in cadence Virtuoso. By Observing the frequency response of pass transistor and transmission gates, the transmission gates frequency response provides good roll-off compared to pass transistor frequency response. The combination of both an PMOS and NMOS in transmission gate arrangement avoids the problem of reduced noise margin. If the same designing of low pass filter done by 45nm Technology in cadence virtuoso then we can achieve more accurate results.

Transient Mitigation Using an Auxiliary Circuit in Cascaded DC–DC Converter Systems With Virtual Impedance Control

Most dc power distribution architectures are organized as a typical cascaded converter system that is composed of source and load converters, and may experience a system oscillation due to the negative impedance effect of constant power loads. The load-side virtual impedance method is a possible solution to such stability problem, which however makes the dynamic response of the load converter slow, and thus increases the requirement of the filter capacitance. In this article, an auxiliary circuit that is connected to the output port of the load converter is proposed to enhance the transient performance of the power converter system, while the system can be stabilized by the virtual impedance method. The control and parameter design of the proposed auxiliary circuit is introduced. The capacitance requirement of the system for an expected transient deviation of the output voltage is significantly reduced by using the proposed auxiliary circuit. An example design is given to verify the feasibility of the proposed method with simulation analysis and experimental results.

Technical Analysis of Vehicle Shutdown Accident Caused by Short Circuit of Filter Capacitor in Traction System

Technical Analysis of Vehicle Shutdown Accident Caused by Short Circuit of Filter Capacitor in Traction System

A Low Supply Voltage, Low Line Sensitivity and High PSRR Subthreshold CMOS Voltage Reference

The paper presents a low supply voltage CMOS voltage reference with low line sensitivity and high PSRR. Generally, the reference voltage is obtained using both complementary-to-absolute-temperature (CTAT) current and proportional-to-absolute-temperature (PTAT) current. This technique increases the complexity and area of the reference circuit. To overcome these drawbacks, the temperature compensated reference voltage has been proposed using only CTAT currents. Mostly, the CTAT current generators are simple, power-efficient, and area-efficient as compared to the PTAT current generators. The negative feedback loop has been formed in the proposed design to obtain a supply independent CTAT current and to avoid the use of startup drivers. The proposed circuit has been designed using Cadence virtuoso analog design environment in BSIM3V3 180[Formula: see text]nm CMOS technology. The simulation results of the proposed circuit show a reference voltage of 312[Formula: see text]mV with a temperature coefficient (TC) of 38.85[Formula: see text]ppm/∘C over a wide temperature range of [Formula: see text]C to 125∘C with a supply voltage of 0.8[Formula: see text]V. The line sensitivity is 0.027% [Formula: see text] with a supply voltage ranging from 0.8[Formula: see text]V to 3[Formula: see text]V. The power supply rejection ratio (PSRR) without using any capacitive filter is observed as [Formula: see text] and [Formula: see text][Formula: see text]dB at 100[Formula: see text]Hz and 100[Formula: see text]kHz frequency, respectively. The circuit is simple and occupies a chip area of 0.0027[Formula: see text]mm2.

Harmonic Mitigation Using Passive Harmonic Filters: Case Study in a Steel Mill Power System

In this study, we mitigated the harmonic voltage in a power system that contained the roughing mill (RM) and finishing mill (FM) motor drives. AC/DC converter type RM drive is a non-linear, large-capacity varying load that adversely affects power quality, e.g., a flicker, voltage distortion, etc. The voltage drop can be compensated within a certain limit by using the proper capacity of a power capacitor bank. In addition, the voltage distortion can be controlled as per the guidelines of IEEE Std. 519 using the passive harmonic filter corresponding to the characteristic harmonics of the motor drive load. The passive harmonic filter can provide an economical solution by mitigating the harmonic distortion with a proper reactive power supply. However, at the planning level, attention should be paid to avoid system overvoltage that is caused by the leading power under light load conditions and also the problem of parallel resonance between the harmonic filter and the step-down transformer. In addition, when designing the filter reactor, the K-factor and peak voltage must be considered; the filter capacitor also requires a dielectric material that considers the harmonic peak voltage. The purpose of this study was to acquire a better understanding of the filter applications as well as verify the field measurement, analysis, and design of harmonic filters together with its performance.

A Study to Resist Conduced Interference from GIS Bus-Charging Currents Switching for Electronic Current Transformer

In this paper, we study the conducted interference to an electronic current transformer introduced in the process of bus-charging currents which are caused by switching a gas insulated switchgear (GIS) disconnector. To cope with these issues, the EMTP-ATP and Matlab/Simulink software are used to carry out equivalent modeling simulations and experimental research, respectively. More specifically, the very fast transient current generated by disconnector switching (DS) is used as the input source of the equivalent simulation model of the Rogowski coil, and the characteristics of conducted interference waveforms of the Rogowski coil, the active integrator and filter outputs under single and multiple breakdowns are analyzed step by step. Moreover, several anti-interference methods are proposed to improve the resistance to the high-voltage and high-frequency conducted interference for the Rogowski coil, such as reducing the Rogowski cut-off frequency, increasing the transient voltage suppressor (TVS), active filter, and Cy capacitor. Besides, the study also reveals that the residual charge of the integral capacitor will discharge with a time constant τ = 1 s after arc quenching with the first-order discharge circuit, which is composed of the feedback resistance and the integral capacitor C. Lastly, the experimental results demonstrate the correctness of the modeling method proposed in this paper and the effectiveness of anti-interference measures.