Filter Capacitor Research Articles

Design of Voltage–Current Reference Source in CMOS Technology

A design methodology for a resistorless low-power two-in-one voltage and current reference source working in subthreshold and moderate regions is described. The presented novel universal reference voltage–current source was implemented in ten different designs for seven different CMOS technologies. Six versions of these designs were silicon-proven using four different CMOS technologies. The example of implementation in 130 nm technology provides a reference current of 5 µA and reference voltage of 800 mV at supply voltages ranging from 0.9 V to 2.0 V with a total current consumption of 15 µA. The proposed circuit occupies a 1200 µm2 chip area and achieves 280 and 118 ppm/°C for all process corners and temperature variation from −40 °C to 125 °C. The power supply rejection ratio of output IREF without any filtering capacitor at 100 Hz and 10 MHz is 128 dB and 100 dB, respectively. The equivalent output current noise in the bandwidth from 1 Hz to 10 MHz reaches 9.1 nARMS.

ЕКСПЕРИМЕНТАЛЬНІ ДОСЛІДЖЕННЯ БЕЗКОНТАКТНИХ МАГНІТОЕЛЕКТРИЧНИХ ТАХОГЕНЕРАТОРІВ

The paper is devoted to the study of the characteristics and operating modes of a brushless magneto-electric tachogenerator, which is implemented on the basis of a traditional radial electric machine with a slotless stator and permanent magnets on the rotor. Options for generating an DC output signal using diode and transistor rectifiers have been studied. The dependences of the average value of the output signal, the slope of the output signal, the coefficient of deviation of the characteristic from the specified value and the pulsation coefficient were obtained depending on the rotation speed of the rotor shaft. The influence of the capacitance of the filter capacitor on the magnitude of the output signal ripple amplitude has been studied. Ref. 13, fig. 9, table.

High-performance MIM-type aluminum electrolytic capacitors with durable waterproof and wide temperature window

Capacitors are indispensable components of electronic circuits. Filter capacitors, mainly dominated by electrolytic capacitors, are critical for the accurate power supply of integrated circuits for central processors and storage devices, affecting the performance of advanced and sophisticated electronic equipment. However, electrolytic capacitors are restricted in working temperatures (<150 °C) and humidity conditions due to the inherent characteristics of MnO2 or polymer cathodes that tend to deteriorate at high temperatures and moisture. Here, high temperature resistant and conductivity SnO2 cathode and MIM-like (SnO2/AAO/Al) structures are introduced into aluminum electrolytic capacitors via ALD technology. First achieved in a higher temperature window (-60 °C∼330 °C), the capacitor maintains a stable capacity (114.5 ± 3.6 μF/cm2) and phase angles (-89.5 ± 0.2°) at 120 Hz. The tight stacking and conformability of ALD even allows unencapsulated devices to exhibit durable waterproof, showing stable performance for immersion in water within 90 days. Moreover, a thin amorphous Al2O3 (A) as buffer layer is introduced at electrode/dielectric interface, aiming to barrier the interfacial atomic diffusion at the SnO2/AAO. A stable vdW SnO2/A/AAO interfaces is obtained, proven by MD and DFT calculations. Impressively, the capacitor exhibits high reliability with high breakdown field strength (5.5 MV/cm), low leakage current (7.2 × 10–7 A/cm2 at 1 V) and low loss (2% at 120 Hz). Applied in circuits, the capacitor filters 100 kHz signal with a Vripple of only 15 mV and shows excellent charging and discharging behaviors. The work may pave the way for the practical application of electrolytic capacitors in harsh working environments.

MANUFACTURING AND TESTING HIGH VOLTAGE FILTER CAPACITORS

This paper presents the manufacturing and testing methods of 30kV and 33nF high voltage filter capacitors. One of the biggest advantages of small companies is that they are able to produce a high diversity of capacitors in small quantities. One of the prices of this flexibility is a higher level of manual manufacturing process in production. But this higher level of manual manufacturing does not mean lower quality in the final product. For high quality products in the high voltage industry, it is necessary to do routine tests in all of the products. For high voltage capacitors the following three tests must be done to ensure quality: voltage strength test, partial discharge test, capacitance and dissipation factor test. The capacitance and dissipation factor test have to be done at different voltage levels. The voltage strength test has to be done at least 20% higher than the rated voltage. This kind of test gives us information not only about the quality of the product itself, but about distribution of the capacitance for example, or about the strength of the production process, and about the quality management system of the company.

A buck converter with adaptive on-time control based on ripple compensation

Abstract This paper proposes a novel adaptive on-time control Buck converter based on ripple compensation. By superimposing high-sampling-precision inductor current ripples on the feedback loop, the ripple of the feedback voltage is enhanced. This approach effectively addresses subharmonic oscillations observed in ripple-controlled Buck converters, particularly when the equivalent series resistance (ESR) of the output filter capacitor is low. The proposed control method enhances system stability and exhibits excellent transient response characteristics. Simulations using Simplis demonstrate high accuracy in the output voltage (with ripples as low as 2mV). The comparative analysis establishes the superior merit of this design.

The Impact of Rectifier Filter Capacitance on Buck Converter Output Voltage in Wireless Power Receiver System With Input Current Source

The Impact of Rectifier Filter Capacitance on Buck Converter Output Voltage in Wireless Power Receiver System With Input Current Source

К выбору параметров регулятора непосредственного понижающего преобразователя с одноконтурной системой управления с учетом динамических нелинейностей

The article is devoted to the issues of choosing the parameters of a proportional-integral-differentiating regulator of a single loop control system with a buck converter taking into account dynamic nonlinearities This problem arises when it is necessary to design pulsed voltage conver¬ters with increased performance, when it is necessary to increase the cutoff frequency of an open-loop control loop without the possibility of increasing the carrier frequency of pulse width modulation due to limitations of the element base, which in some cases leads to the appearance of nonlinear effects. This must be taken into account when choosing both the open-loop cutoff frequency and the stability margin. The article proposes a nonlinear dynamic model of a direct buck converter with a proportional-integral-differentiating regulator both in the form of a piecewise smooth system of differential equations and in the form of a Poincaré map. A method for selecting controller parameters is proposed for a given open-loop cutoff frequency, and a given stability margin, as well as for given ranges of input voltage and load resistance based on the use of numerical methods for solving systems of nonlinear equations with given restrictions. The nonlinear dynamics of the system was studied for various sets of controller parameters. It is shown that with an increase in the cutoff frequency and small stability margins, undesirable dynamic modes may arise in the system when the filter capacitance drops within the calculated values, while linear dynamic models show the stability of the system. To eliminate the possibility of the emergence of undesirable modes, it is necessary to increase the stability margin with subsequent monitoring of the results using a nonlinear dynamic model. The proposed method for selecting the cutoff frequency of an open loop and the phase stability margin, based on the analysis of nonlinear dyna¬mics, allows you to design power supplies with increased performance.

Robust Voltage Control of a Single-Phase UPS Inverter Utilizing LMI-Based Optimization with All-Pass Filter Under System Uncertainty

This paper proposes a systematic control design for a single-phase LC-filtered inverter considering uncertain system parameters. One major difficulty in controlling single-phase power converters is the lack of a direct conversion method for transforming single-phase signals into dq-frame signals. By employing an all-pass filter in this proposed approach, it is possible to control the output voltage in terms of DC quantity or the dq-rotating frame. Furthermore, voltage stability and harmonic distortion (THD) minimization of the uninterruptible power supply (UPS) are major concerns in inverter design. Therefore, this controller uses integral action to get rid of steady-state errors and stabilize the closed-loop system by the state feedback control. In order to enlarge and guarantee the stability range in the presence of potential parameter fluctuations, an uncertainty model is being considered. In this context, the uncertainty models refer to the potential model with variations in the filter's inductance and capacitance caused by operating temperature, aging, and various external factors. The efficacy of the control approach is assessed through simulations and experiments, with the objective of comparing its results with those of the PI control using a control board featuring a TMS320F28335 digital signal processor. Consequently, the proposed approach offers lower THD at every load step with lesser afford in performance tuning in comparison to the PI method.

High-frequency harmonics suppression in high-speed railway through magnetic integrated LLCL filter.

The traction converter modulation generates switching-frequencies current harmonics. The trapped filters can eliminate these switching harmonics, reducing total inductance and filter size. Nonetheless, in comparison with the typical inductor-capacitor-inductor (LCL) filter, the trap inductor needs a larger magnetic core. Moreover, the trapped filter has not been analyzed in the traction systems. This paper proposes a magnetic integrated inductor-trap-inductor (LLCL) filter to decrease the filter's size and investigate its application in traction converters. In fact, the application range of this filter is quite broad, and it can be used in various electrical power systems, including industrial power systems, renewable energy systems, transportation systems, and building power systems. The LC-trap may be formed by connecting the equivalent trap inductor, introduced through the magnetic coupling between inverter-side and grid-side inductors, in series with the filter capacitor. Furthermore, for H-bridge unipolar pulse width modulation (PWM) traction converters, the prominent switching harmonics are concentrated at the double switching frequencies. Therefore, the stability zone is expanded by moving the resonance above the Nyquist frequency. The presented filter's features and design are thoroughly analyzed. The proposed method is finally validated by the MATLAB/Simulink simulation and hardware-in-the-loop (HIL) experimental results. Compared to the discrete windings, the integrated ones can save two magnetic cores. Furthermore, the proposed filter can meet IEEE criteria with 0.3% for all the harmonics and total harmonic distortion (THD) of 2.15% of the grid-side current.

Investigation of bidirectional three-phase four-leg converter with LCL filter

A three-phase four-leg bidirectional power converter used as an input stage of an energy storage system using the inductance (L), capacitance (C), and inductance (L) or LCL filter on the grid side is considered. The article provides a variant of the three-phase four-leg bidirectional converter control system implementation based on 3D space vector pulse-width modulation and per-phase voltage control. A brief analysis of the applied control algorithms of the three-phase four-leg bidirectional converter in inverter and rectifier modes is given. A computer model has been built to investigate the operating modes of the converters of the designated class with both balanced and unbalanced load. Studies were carried out by computer modeling methods in order to optimize the parameters of the LCL filter on the grid side with bidirectional energy exchange. Optimal LCL filter parameters and modulation frequencies are determined for the developed converter, providing acceptable quality indicators when operating in bidirectional mode.

Active Damping for LC-Filtered PMSM Based on Low-Pass Filter Capacitor Current Feedback and Extended State Observer

Active Damping for <i>LC</i>-Filtered PMSM Based on Low-Pass Filter Capacitor Current Feedback and Extended State Observer

Optimization Design of Temperature Field Distribution for AC High Voltage Parallel Capacitors

Abstract With the change in the overall harmonic working background of the system, the harmonic current spectrum borne by high-voltage AC shunt capacitors becomes increasingly complex, particularly with a gradual increase in high-frequency harmonic content. The wide frequency band, large value range, and long duration of harmonic current lead to increased heating of the capacitor. In this paper, a thermal field physical model is established for an AC parallel filter capacitor based on the skin effect, and trends are analysed in the current distribution of the capacitor plate under the skin effect. Furthermore, based on this established model, it is analysed how harmonic order and capacitor placement mode affect temperature field distribution within the capacitor, and it is concluded that these factors impact temperature rise release. This research lays a theoretical foundation for designing capacitor unit structures.

An Efficient Shunt Modulated AC Green Plug–Switched Filter Compensation Scheme for Nonlinear Loads

Nonlinear loads, crucial components of power system grids, pose a challenge due to harmonics injection. This work tackles this issue with a novel modified green plug–switched filter compensation scheme using fuzzy logic controllers. This innovative scheme presented in this paper utilizes dual action pulse width modulation to ensure switching functions from harmonics reduction and capacitive compensation for inrush nonlinear-type AC loads. The scheme’s multi-loop regulations and online switching effectively handle dynamic-type slow-acting inrush, motorized- and other rectifier-type nonlinear loads, enhancing the power factor, power quality at source and load buses, and reducing the total harmonics distortion at the key source and sensitive nonlinear load buses. A simulation model in the MATLAB/SIMULINK-2023b software environment demonstrates the efficiency of the proposed FACTS technique. The modulated dual mode switched filter-capacitive compensation scheme controlled by a fuzzy logic controller ensures less harmonics distortion and improved voltage stabilization. The results show that voltage, current, active power, reactive power, power factor regulation, and effective energy utilization are achievable with the designed Flexible AC Transmission System-Modulated Filter Capacitor Compensation–Switched Filter Compensator (FACTS-MFCC-SFC). The switched modulated AC green plug filter significantly improves power quality and enhances power factor in cases of inrush and nonlinear loads.

A 3X and X/3 voltage conversion‐based bidirectional CuK converter for supercapacitor‐assisted electric vehicles

AbstractIn this paper, a high‐gain bidirectional DC–DC converter is presented for electric vehicles where low terminal voltage source like a supercapacitor is used along with the battery. The supercapacitor provides or absorbs large amount power during acceleration and deacceleration and extends the life of main energy source, that is, battery. The supercapacitor terminal voltage varies considerably during charging and discharging activities; hence, a bidirectional DC–DC converter with a high‐voltage conversion ratio must be used to connect the lower supercapacitor voltage to the higher DC‐link voltage. Such application requires steep voltage conversion ratio along with continuous gain‐based bidirectional DC–DC converters. In this study, a typical CuK converter is employed to produce a voltage gain of 3X and X/3 with the ability to transmit power in both directions. The suggested bidirectional converter has a continuous current on both the low‐ and high‐voltage sides, which reduces the requirement for filter capacitance and increases the lifespan of the supercapacitor and DC‐link capacitor. Further, inherent inrush current safety is provided by the proposed converter as the inclusion of an inductor in the path of capacitor charging or discharging. Both in the charging and discharging phases, a detailed steady‐state analysis of the proposed circuit was performed. Moreover, a deep discharge analysis of the supercapacitor and its implication on the performance of the converter is also investigated.

Magnetic integrated double-trap filter utilizing the mutual inductance for reducing current harmonics in high-speed railway traction inverters

Current harmonics are generated at the switching frequency and its multiples when the traction converters are modulated. To address this, multi-trap filters are introduced, which are capable of selectively eliminating these specific harmonics to the limits set by IEEE 519-2014. This targeted removal significantly reduces the need for high total inductance, thereby allowing for a more compact filter design. Comparatively, to traditional inductor-capacitor-inductor (LCL) filters, more magnetic cores are needed for trap inductors. Furthermore, the traction systems have not been examined in conjunction with multi-trap filters. To reduce the filter size and investigate its application in traction converters, this paper presents an integrated double-trap LCL (DTLCL) filter. A tiny capacitor is connected in parallel with the grid-side inductor to form one LC-trap. In addition, another LC-trap is formed by connecting the equivalent trap inductor, introduced through the magnetic coupling between inverter-side and grid-side inductors, in series with the filter capacitor. The presented filters' features are thoroughly analyzed, and the design method has been developed. Finally, the simulation and hardware-in-the-loop (HIL) experiment results validate the proposed method's viability and efficacy. Compared to the discrete windings, the integrated ones enable a size decrease of two cores. Furthermore, the proposed filters can meet IEEE 519-2014 criteria with 0.3% for all the current switching harmonics and total harmonic distortion (THD) of 2.36% of the grid‐side current.

Energy Harvesting Floor Tile Using Piezoelectric Patches for Low-Power Applications

Abstract Purpose One of the sustainable energy sources derived from kinetic energy is human footsteps. This research sought to find a substitute for conventional power sources to lessen dependence on them. As a result, a floor tile excited by human footsteps was demonstrated and presented to generate usable electrical power. Methods Piezoelectric patches, hot melt glue sticks, wood plates, and foam plates are just a few of the commercially available materials used in the suggested technique, making it suitable and practical. In addition to the components, uncomplicated circuits like a voltage multiplier and rectifier with a capacitance filter were employed for the electrical power capture. The proposed prototype has a length of 455 mm and a width of 405 mm. Results Two LEDs were effectively illuminated as an actual load using electrical energy collected from human footsteps. The maximum useful power that could be harvested successfully via the proposed floor tile (one tile) was 246 mW, with an approximate cost of $10.2. Conclusions Designing an array of footsteps-based energy harvesting tiles covering broad areas to maximize the harvested power could be considered as a future work. Moreover, the number of pedestrians variable can be also studied for the proposed design of this study in a real excitation environment such as a railway station, subway station, street, discotheque, and wedding festival hall.

Fabrication of RC filters from a single printed Zn layer by reactive inkjet printing

This paper presents the development of planar zinc (Zn) resistor–capacitor (RC) filters from a single printed layer that are both printed and treated at room temperature. The fabrication process involves screen printing the resistor, capacitor and interconnects in a single patterned layer on kraft paper substrates using a Zn microparticle ink. In order to form a distinct resistor and capacitor in the patterned structure, reactive inkjet printing (RIJ) was performed to selectively dispense acetic acid on the RC filter pattern to achieve regions with highly contrasting resistance. The required high degree of spatial contrast was achieved using the positional control of the inkjet printer combined with the number of print passes and drop spacing used to dispense the acetic acid droplets. X-ray diffraction and scanning electron microscopy showed the crystal structure and grain size of Zn microparticles remained unchanged with increasing acetic acid exposure while the prominence of cold-welding increased with increasing exposure. Zn-based RC filters sharing a common set of dimensions but with a wide range of corner frequencies were successfully fabricated using this process. For a fixed filter geometry, the corner frequencies could be tuned from ∼7 kHz to ∼1 MHz as the number of print passes used to form the resistor increased in a stepwise manner. To the best of our knowledge, this is the first room temperature printing process to produce side-by-side resistors and conductors from the same printed layer and the first printing process of any type to produce RC filters with such a wide range of corner frequencies.

A Novel Single-Stage AC/DC Converter Integrated Interleaved DCM Boost PFC and LLC DC–DC With Reduced Bus Voltage

Due to the applied pulse frequency modulation (PFM) control and switch integration, single-stage Boost-LLC AC/DC converters suffer from high bus voltage which makes them difficult to operate for high voltage input. To solve this issue, a novel single-stage AC/DC Converter by incorporating the interleaved DCM boost cell and an LLC cell is proposed. Different from the existing topology, in the proposed converter, two capacitors employed for splitting the ac input voltage into two parts are placed before the rectifier bridge. Thus, the voltage across each PFC cell is halved and the bus voltage can be significantly reduced. Furthermore, two high-frequency diodes and one filter capacitor are omitted, which helps improve the zero-crossing distortion of the input current. More importantly, the circuit efficiency is thus increased. Hence, low bus voltage, low component count, and high efficiency are the main advantages of the proposed converter. Simulations and experimental results are presented to prove the above features of the proposed converter.

Analysis of AC filter detuning characteristics and improvement measures in converter station

Shift of parameters of the double-tuned AC filter component and failure in prompt correction of detuning frequency may affect the filtering effect of the AC filter. Therefore, this paper studies impedance-frequency characteristics of the double-tuned AC filter according to detuned recording data of the A-typed double-tuned AC filter in the Congxi converter station. It analyzes the variation of the impedance-frequency characteristic curves and relative change rate of resonant frequency as there are deviations between actual values and rated values of each filter capacitance and inductance elements in different degrees, and concludes that variation of the parameter of each element in different degrees may cause different deviations of resonant points of the double-tuned AC filter. MATLAB simulation has proved it can reduce the detuning degree and improve the filtering performance of the filter by adjusting the parameters of the variable reactor to change in the opposite direction of the parameters of the resonant capacitor.

High-Voltage Gain Ripple-Free Resonant DC–DC Converter Using Active Voltage-Quadrupler

This paper presents a high-voltage gain ripple-free resonant DC/DC converter using an active voltage-quadrupler. By incorporating an active voltage-quadrupler at the secondary side of the transformer, the circuit achieved a very high-voltage gain. Without using extra input inductors, the inherent dual transformer plus interleaved active-clamped circuit operating with a fixed duty-ratio of 0.5 generate a ripple-free input current, which extends the lifetime of the fuel cell and shrinks the size of the input capacitive filter. This asymmetric structure of the active-clamp circuit requires an extra dead time for one of the secondary-side switches to achieve zero-voltage switching (ZVS) turn-on. After the extra dead time for one of the secondary-side switches is applied, all power components of the active voltage quadrupler cell are turned on and off with soft switching. The resonant capacitor voltages are unbalanced due to the extra dead time, but they are compensated by applying different secondary-side duty ratios. The operating principle and steady-state characteristics of the proposed converter were analyzed in detail. We built a 1-kW/700-V prototype that copes with 48-72 V inputs, and tested to verify the theoretical analysis.