Pass Filter Circuit Research Articles

Self-switching circuit of TENG for energy storage and power management in harvesting wind energy

As an important green energy in our life, natural wind energy is widely used in power generation. Triboelectric nanogenerator (TENG) can convert wind energy in the environment into electrical signal. In this study, two independent TENGs in parallel (FHS-TENG) and the power management circuit composed of passive self-switching circuit and LC filter circuit constitute a self-supplying system, which is committed to harvesting wind energy in the environment and outputting stable voltage and improving energy storage performance. The self-switching circuit mainly includes rectifier module, energy storage module, the self-switching module, and filter module. And the on/off state of the passive self-switching is mainly controlled by two transistors, which implements the effect of switch. The results demonstrate that the energy stored by the power management circuit is more than 100 times higher than that of the universal circuit at 100 μF capacitor, and the calculator is in stable working order in simulated wind conditions. This work provides a new strategy for the passive electronic switch of TENG and the improvement of circuit energy storage performance, which is meaningful for the further application and industrialization of TENG.

A method to reduce excitation circuit noise of fluxgate sensor

This paper designs a three-axis closed-loop fluxgate system for geophysical prospecting, which contains excitation, induction, and feedback circuits. By analyzing and comparing the noise levels before and after the system operation, it is concluded that the main factor affecting the fluxgate performance is the excitation circuit noise. By analyzing the principle of fluxgate, the noise on the induction signal and feedback signal can reduce the accuracy of fluxgate and even lead to system instability in serious cases. In this paper, a passive filter circuit is designed to reduce the noise associated with the fundamental frequency from the source to ensure stable operation and improved performance of the system. Simulation and experimental data show that after using the filter circuit, the secondary frequency noise level of the induction signal and the feedback signal noise level are reduced by 10 times, and the trend capturing capability under external magnetic field is greatly improved.

Tunable and foldable paper-based passive electronic components and filter circuits

Tunable and foldable paper-based passive electronic components and filter circuits

Fractional Order Capacitor in First-Order and Second-Order Filter

Background: Fractional order Butterworth and Chebyshev (low-pass filter circuits, highpass filter circuits and band-pass filters circuits) types of first and second order filter circuits have been simulated and their transfer function are derived. The effect of change of the fractional order α on the behavior of the circuits is investigated. Objective: This paper presents the use of fractional order capacitor in active filters. The expressions for the magnitude, phase, the quality factor, the right-phase frequencies, and the half power frequencies are derived and compared with their previous counterpart. Methods: The circuits have been simulated using Orcad as well as MATLAB for the different value of α. We have developed the fractional gain and phase equations for low pass filter circuits, high pass filter circuits and band pass filter circuits in Sallen-Key topology. Results: It is observed that the bandwidth increases significantly with fractional order other than unity for the low pass as well as high pass and band pass filters. Conclusion: We have also seen that in the frequency domain, the magnitude and phase plots in the stop band change nearly linearly with the fractional order. If we compare the fractional Butterworth filters for low-pass and high-pass type with conventional filters then we find that the roll-off rate is equal to the next higher order filter.

A Real-Time Heart Rate Signal Detection using an Electronic Stethoscope with Labview.

Better accurate stethoscope measurements have been needed to diagnose heart problems earlier, monitor patients, and provide initial clinical data for physicians. This study aims to evaluate an electronic stethoscope for automatic identification of heart rate by monitoring Beats Per Minute (BPM) in real-time. In this work, a new design with a low cost electronic stethoscope is designed and implemented as a simple circuit for a replacement with conventional stethoscopes. This presented a low cost stethoscopes consisting of a preamplifier, low-pass filter, high-pass filter, microcontroller and Bluetooth. This simulation and experimental study was carried out for electronic circuit design testing. The condenser microphone transmited the signal into the signal conditioning circuit, and amplified it from 10 to 30 times. The low- and high- pass filter circuit was with cutoffs of 180 Hz and 50 Hz, respectively. The result shows that the fourth-order Butterworth filter was the best filter, with a gain of 0.707 Volt, -3.01 dB, and 0.782 Volt, -2.137 dB, respectively. The real-time measurements using the system are not significantly different from the manual measurements, with around 2-5%, with a delay of 1.7 to 2 seconds. The results indicated that an electronic stethoscope system could provide suitable information for BPM value and could display heart sound signals.

Evolutionary design model of passive filter circuit for practical application

Evolutionary circuit design is a promising way to study new circuit design methodologies, and the passive filter is the most basic circuit module widely existing in modern electronic systems. Focused on the basic and fatal criterion related to the filter circuit design, this paper presents a novel evolutionary design model of passive filter circuit. The proposed model includes a circuit representation method for passive filter circuit design based on circuit cells and the corresponding real encoding scheme, a fast fitness calculation method avoiding expensive SPICE simulations, and a simple and effective cell-based differential evolution algorithm. Experimental results show that the proposed model can quickly obtain filter circuits for challenging specifications. Under harsh design criteria, the design performance of the proposed model is not inferior to that of some advanced professional design techniques based on traditional design ideas.

Second-Harmonic Ripple Voltage Suppression of Integrated Single-Phase Pulsewidth Modulation Rectifier Charging System for EVs

In single-phase ac battery chargers, pulsating power at twice of the line frequency is delivered by the ac source resulting in second-harmonic ripple voltage on the dc-link if additional passive or active filter (AF) circuits are not used. In this article, an inductance-based AF using the leakage inductance of the machine windings along with a current compensation control method is proposed. No additional passive components are required. The machine used in this article has a double-layer winding with a center tap in each phase and the winding structure of the machine is special in that the pulsating magnetomotive force of the whole phase winding can be cancelled when currents flow into the central tap. In this article, the operating principle and control strategy of the AF with the inductive energy storage are analyzed. Finally, a 400-W experimental prototype is developed and the experimental results are used to validate the performance and feasibility of the proposed converter and control strategy.

A Study on Dielectric Properties of Cadmium Sulfide–Zinc Sulfide Core–Shell Nanocomposites for Application as Nanoelectronic Filter Component in the Microwave Domain

Complex permittivities of cadmium sulfide (CdS), zinc sulfide (ZnS), and of cadmium sulfide–zinc sulfide (CdS/ZnS) core–shell nanoparticles embedded in a polyvinyl alcohol matrix (PVA) were measured in liquid phase using a VectorNetwork Analyzer in the frequency range of 500 MHz–10 GHz. These nanocomposites are modeled as an embedded capacitor, and their electric field distribution and polarization have been studied using COMSOL Multiphysics software. By varying the thickness of the shell and the number of inclusions, the capacitance values were estimated. It was observed that CdS, ZnS and CdS/ZnS core–shell nanoparticles embedded in a polyvinyl alcohol matrix show capacitive behavior. There is a strong influence of the dielectric properties in the capacitive behavior of the embedded nanocapacitor. The capping matrix, position and filling factors of nanoinclusions all affect the capacitive behavior of the tested nanocomposites. Application of the CdS, ZnS and CdS/ZnS core–shell nanocomposite as the passive low-pass filter circuit has also been investigated. From the present study, it has been found that CdS/ZnS core–shell nanoparticles embedded in PVA matrix are potential structures for application as nanoelectronic filter components in different areas of communication.

On the Passivity of Wave Digital Networks

With inventing the wave digital (WD) filters almost fifty years ago, Alfred Fettweis laid the foundation to a completely new approach for the digital modeling of passive analog filter circuits. Soon it became clear that not only classical filter structures could be modeled by the WD concept, but also other linear and nonlinear electrical circuits and, moreover, even general physical systems, including those being described by partial differential equations. Of particular significance is the fact that this approach makes it possible to transfer the important physical concepts of passivity and losslessness from the analog to the digital domain. As a result, properly designed passive WD filters exhibit a very low coefficient sensitivity which considerably reduces the hardware requirements. This is clearly one important issue of the WD concept. However, even more important are the excellent stability properties which can be achieved by applying the concepts of passivity and incremental passivity. In this paper a review of these latter properties and its consequences will be presented. It will in particular be discussed how the passivity can be preserved even under finite arithmetic conditions.

Complexity and onset of chaos control in a DC glow discharge magnetized plasma using all pass filter

Complexity dynamics of the plasma oscillations is explored under the variation of the discharge voltages in two constant magnetic fields and control of complexity, particularly chaos, has been achieved by using an all pass filter circuit. Appearance of the long diagonal lines in the recurrence plot of the controlled signal, strongly conjecture the regularity of the system after switch on the control. The negative to positive transition of the skewness and the significant change of the intensity of color in the wavelet spectrum also indicates the chaos to order transitions in the plasma system once the control is switch on.

Power Quality Analysis of Integration Photovoltaic Generator to Three Phase Grid under Variable Solar Irradiance Level

Objective of research is to analyze the influence of solar irradiance and integration of photovoltaic (PV) generator to power quality of three phase grid on the constant temperature and load, based on changes in some level of integration of PV generator. Power quality aspects studied are fluctuation or changing, and harmonics of voltage and current on eight scenarios PV generator connected to three-phase grid, using passive filter circuit model double band pass (double tuned). Research shows that voltage and current values on the PCC bus before use double tuned passive filter on the condition only connect single generator is still stable. However, if the PV generator connected to the three phase grid, amounted to more than one generation, voltage and current grid becomes unstable (fluctuation). At the level of solar radiation remains, the greater number of PV generators connected to the grid three-phase, then the values of voltage and current THD increases. At the level of solar irradiance increases, average THD of voltage and current grid also increased. Avarage THD of voltage and current grid is reduced after double tuned passive filter installed. Therefore, double tuned passive filter able to improve profile of voltage and current THD grid as a result of the integration of a number of PV power generators in three-phase grid according IEEE Standard 519-1992. Simulation and analysis of this research use Matlab/Simulink.

Precise detection and elimination of grid injected DC from single phase inverters

Single-phase voltage source inverters are used for connecting small scale renewable energy sources to low voltage distribution networks. They operate to supply the network with sinusoidal current. If output transformers are not used, these inverters must prevent excessive dc current injection, which may cause detrimental effects in the network. In this study, the causes of dc current injection in a common inverter topology are analyzed. This work explains the design and test of a passive filter circuit precisely measuring the dc component in the inverter output current. The filtered dc signal is then used to control the single phase inverter for the objective to keep the dc injection low — below the standard limit. Characteristics of the proposed method are illustrated using simulation and experimental results.

Ultra-Compact WiMAX Bandpass Filter Embedded Into a Printed Circuit Board With a ${\rm SrTiO}_{3}$ Composite Layer

An ultra-compact bandpass filter has been developed for 2.3-2.7 GHz worldwide interoperability used for microwave access applications. The proposed filter was fully embedded into a multilayered printed circuit board (PCB) with a high dielectric strontium titanate (SrTiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ) composite film layer. In order to reduce the size of the filter and to avoid unwanted 3-D electromagnetic coupling between the embedded passive filter circuit elements, the proposed filter was designed using J-inverter transformation technology. Two grounding via inductors and a single grounding capacitor were also utilized to generate three independent finite transmission zeros to enhance the rejection characteristics at the proper frequency bands. Since the J-inverter transformed filter circuit elements could be designed with relatively small inductance and large capacitance values, the high dielectric composite film was highly effective in reducing the size and improving the performance of the filter. The high dielectric film exhibited a dielectric constant of 17, a tangent loss of 0.01, and a capacitance density of 12.2 pF/mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> at 1 GHz. The measured maximum insertion loss in the passband ranged from 2.3 to 2.7 GHz was better than 1.8 dB, with a minimum value of 1.58 dB at 2.6 GHz. The return loss was higher than 15 dB in the passband. The transmission zeros occurred at 1.71 and 5.1 GHz, and provided suppressions of 45 dB at 1.71 GHz, and 54 dB at 5.1 GHz, respectively. The measured group delay was less than 0.8 ns in the passband. The embedded bandpass filter had a volume of 2.6 × 2.6 × 0.55 (H) mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> , which is the smallest one found, compared to previously reported devices, the filter, embedded into the eight-layered packaging substrate with the high dielectric composite layer, dramatically reduced the size up to 56%, and its performance was also much improved in comparison to the one embedded into a conventional six- layered PCB.

Planning and Development of Lab Training Activities for Powerline Communications

This paper discusses the planning and development of student training and activities for the Powerline Communications Laboratory at the Technical Education Institute (TEI), Patras, Greece. Powerline communications is currently an active area of research and development that combines three separate specializations from the standard training of electrical engineers: communications, power, and control systems. A course on powerline communications toward the end of the standard electrical engineer's training provides a useful practice in applying what the students have already been taught in an area that has high potential in modern consumer electronics. The planning of suitable training activities for the students takes into account their background and training at that stage of the course and combines concepts and practices common to communication, power, and control systems. In detail, the training activities involve: (1) familiarization and training with currently available market products for automation/control and broadband powerline communications; (2) open-source software that can be used in the design and simulation of such systems; and (3) fabrication and testing of simple passive filter circuits that can be used for signal coupling into the mains power lines for custom applications.

Automated synthesis of passive filter circuits including parasitic effects by genetic programming

In this paper, we propose a genetic programing method to synthesize passive filter circuits including parasitic effects, which are very common in high-frequency application. This approach allows circuit topology and component values to be evolved simultaneously; therefore, novel circuits different from those generated by traditional methods can be explored. Experimental results show the proposed method can effectively generate not only compliant but also efficient solutions of such problems where the traditional approaches fail.

Practical Passive Filter Synthesis Using Genetic Programming

This paper proposes a genetic programming method to synthesize passive filter circuits. This method allows both the circuit topology and the component values to be evolved simultaneously. Experiments show that this method is fast and capable of generating circuits which are more economical than those generated by traditional design approaches. In addition, we take into account practical design considerations at high-frequency applications, where the component values are frequency-dependent and restricted to some discrete values. Experimental results show that our method can effectively generate not only compliant but also economical circuits for practical design tasks.

Wireless strain monitoring using electrical capacitance change of tire:part II—passive

In-service strain monitoring of tires of automobiles is quite effective for improvingthe reliability of tires and design tools. In a previous study, the authors proposeda new wireless strain monitoring method that adopts the tire itself as a sensor,with an oscillator circuit. In the method, steel wires are employed as electrodes tomeasure electrical capacitance changes of tires. A specimen cut from acommercial tire is connected to an oscillator circuit, and the oscillationfrequency changes with the capacitance changes of the tire. This method isvery simple and useful, but it requires a battery to activate the oscillatorcircuit. In the present study, a new passive strain measurement systemutilizing electrical capacitance changes of steel-wire-reinforced tires isproposed and experimentally investigated. The passive wireless strainmonitoring method makes use of the specimen cut from the tire as acondenser of a passive filter circuit. Deformation of the tire causes capacitancechanges of the tire comprised of steel wire and rubber; the change of thecapacitance causes a change of the filtering frequency of a radio wave.Measurement of the frequency of a radio wave passed through the filtercircuit enables us to measure the strain of the tire wirelessly. A rectangularspecimen cut from a commercially available tire is adopted as a specimen.Tension testing is performed and the change of the filtering frequencyis measured during the test. As a result, the method is experimentallyproved to be effective for the passive wireless strain monitoring of tires.

EMC Compliant Harmonic and Reactive Power Compensation Using Passive Filter Cascaded with Shunt Active Filter

A novel control method for active power filters in conjunction with a cascaded passive filter circuit is presented and analysed in this paper in order to comply with EMC regulations. The principles of analysis, design, operation and control of the new circuit equipped with IGBTs are presented. This enables the compensation of rapidly changing harmonics and reactive power. The new configuration improves the rating of the active power filter, reducing power losses in the switches compared to existing and newly developed active filters. Furthermore, the paper also presents a mathematical modelling of the proposed system equations. The frequency response of the proposed system is also discussed. The proposed circuit has been checked using a dedicated software simulation program, which was specifically developed for this purpose. An experimental set-up has been designed and implemented in order to apply the new method using IGBTs and other passive devices.

660 タイヤ構造の電気容量変化を利用した無線ひずみモニタリング

Strain monitoring of tires of automobiles in-service is quite effective to improve reliability of tires and design tools. In the previous study, authors have proposed a new wireless strain monitoring method that adopts a tire itself as a sensor with an oscillator circuit. In the present study, a new passive strain measurement system utilize electric capacitance change of steel wire reinforced tires is proposed and experimentally investigated. The passive wireless strain monitoring method makes use of the specimen cut from the tire as a condenser of a passive filter circuit. Deformation of the tire brings capacitance change of the tire comprises steel wire and rubber; the change of the capacitance makes the change of filtering frequency of radio wave. Measurement of the frequency of radio wave passed through the filter circuit enables us to measure the strain of the tire wirelessly. A rectangular specimen cut from a commercially available tire is adopted as a specimen. Tension test is performed and the change of filtering capacity is measured during the test. As a result, the method is experimentally proved to be effective for the passive wireless strain monitoring of tires.

Enhanced optical-microwave interaction efficiency for radio applications with a hybrid passive filter-fast MQW DFB laser

In this work we present the design and characterization of a simple passive microwave filter circuit with low impedance output. This circuit, designed for optical microwave harmonic mixing of digital signals up to 1 Gbit /s at any harmonic-generated carrier, combines a bandpass filter centered at 9.5 GHz with 1.2-GHz bandwidth and a low-pass filter in the frequency band of 10 kHz-1 GHz, enabling high- and low- frequency modulation schemes. Using this circuit in a hybrid integration with a DFB laser configured as an optical microwave mixer, we demonstrate that an improvement of 6 dB is obtained on both frequency bands. © 1997 John Wiley & Sons, Inc. Microwave Opt Technol Lett 14, 139–140, 1997