Active Filter Circuit Research Articles

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.

The development of Arduino-based low-cost wireless modular device for brainwave acquisition

Brainwave is widely used as an indicator of brain activity and can be detected by electroencephalography (EEG). The development of EEG device has become more advanced along with the invention of low-cost tiny electronic modules and wireless technology. This research aimed to develop a low-cost wireless modular device for brainwave acquisition based on Arduino microcontroller. The system was designed into sensor block for brainwave receiver and conditioning, and mainboard block for data processing. Dry-active electrode was developed as the sensor, followed by preamplifier module which was also installed at the sensor block. Active filter and DRL circuits were developed on the mainboard part. Arduino UNO was used as the main processor of the device. The developed modules were then evaluated using signal generator to examine the module characteristics and consistency. As the result, the preamplifier module was detected to reach 40.34 dB on gain ability. The cutoff frequency on the active filter module was calculated on 31 Hz. Furthermore, Arduino UNO was identified to have a consistency on input and output voltage.

Single-Input Space Vector Based Control System for Ripple Mitigation on Single-Phase Converters1

Applications such as renewable energy generation, electric vehicles, and low-power UPS require single-phase ac/dc conversion. However, this conversion introduces a considerable amount of second-harmonic ripple on the dc link. If not filtered, this distortion hinders the converter's performance as well as the energy quality on both the ac and dc side. To mitigate this problem, a large electrolytic capacitor is usually the solution of choice, which mitigates the voltage ripple, but has drawbacks of its own, including the increased size and cost associated with the large capacitance and the limited lifespan of electrolytic capacitors. Alternative solutions to the problem include integration of an active filter circuit to the converter, which can utilize a storage element with the objective of mitigating power ripple. Such solutions have often been proposed alongside a control system, which is either highly complex or relies on open-loop feedforward techniques. This paper presents a control system, which adapts the single-input space vector concept for a single-phase application and leverages its simplicity and closed-loop architecture, allowing the controller to perform well in the presence of disturbances and parameter uncertainty. Experimental results are provided to elucidate the controller's performance on a single-phase grid-connected photovoltaic array application.

Low-Temperature KHN Active RC Filter Circuit with the Effect of Compensation of Gain Areas of Operational Amplifiers

Low-Temperature KHN Active RC Filter Circuit with the Effect of Compensation of Gain Areas of Operational Amplifiers

New method of analysis and design of frequency and bandwidth reconfigurable active filter

A new method of analysis and design of reconfigurable active bandpass filter is proposed. The proposed method involves matrix manipulation for equating passive inverter impedances with those of active inverter (both input and output impedances). Designing of active filter involves the designing of active inverter and active resonator. The filter performance is analysed in frequency range 500 MHz to 1.5 GHz. The narrow band filter is switched between two bands with varying fractional bandwidth and centre frequency. The physical implementation comprise elements employing ATF 21186 FET on RT Duroid 5880 substrate with dielectric constant 2.2 and thickness 0.127 mm. Active resonator comprises of an active capacitor and a passive inductor. The active inverter along with active resonator employed in active filter circuit provides reconfigurability in frequency (≈200 MHz) as well as in bandwidth with the variation in gain of approximately 8-10 dB. The electrical performance of active band pass filter shows good agreement with the measured response. To best of my knowledge first time integration of active inverter and active capacitor is done. Intergration of such kind allows for frequency as well as bandwidth tuning. The electrical performance of active band pass filter shows slight deviation from with the measured response.

Fully Integrated K-Band Active Bandpass Filter In GPDK 90nm CMOS Technology

Abstract The bandpass filter is one of the essential blocks of every modern RF transceiver. Performance of the transceiver greatly depends on the performance of the bandpass filter. A bandpass filter designed with passive inductors suffers from some drawbacks like large chip size, low-quality factor, less tenability etc. To prevail over these constraints, an active inductor-based bandpass filter circuit has been designed in GPDK-90nm CMOS technology utilizing cadence virtuoso environment. The simulation result shows that the active inductor-based bandpass filter circuit design achieves a gain of 6.79dB, a bandwidth of 5.05 GHz and a noise figure of 3.10dB. The circuit dissipates only 3.55mW power for its operation from a single 1.5V DC supply. By avoiding bulky inductor in the design helped to attain a very small chip area of 127.704μm2.

Active Power Decoupling for Submodules of a Modular Multilevel Converter

The modular multilevel converter (MMC) is receiving wide acceptance in both high- and medium-voltage (MV) applications. However, due to the low (fundamental and second-order) frequency ripple powers in the submodule (SM) capacitors, large capacitance is required to smooth the SM voltage. The SM capacitors account for a large portion of volume and weight in the MMC system. Present methods (e.g., circulating current control, power channels linking upper and lower arms) cannot eliminate the fundamental and second-order ripple powers simultaneously. This paper investigates the feasibility of an active power decoupling technique for solving this issue. By adding a buck-type active power filter (APF) circuit (which contains another energy-storage capacitor), the low-frequency ripple powers can be transferred to the APF capacitor. This significantly reduces the SM voltage ripple and therefore the total capacitance of the SM. To enhance voltage ripple suppression, APF capacitor voltage reference is modified in a closed-loop manner, and a proportional-integral plus repetitive controller is proposed. Simulations and experimental results prove the validity of the method. A comparison with the traditional MMC shows that it can significantly reduce system volume and improve power density. The method is best suited for MV applications where power density is given a high priority.

A Primary Full-Integrated Active Filter Auxiliary Power Module in Electrified Vehicles With Single-Phase Onboard Chargers

In single-phase ac high-voltage (HV) battery chargers, as the input current is enforced to be varying sinusoidally in phase with the input voltage, the pulsating power at two times of the line frequency will be seen on the dc-link. Bulky capacitor bank or extra active filter (AF) circuits are needed to assimilate this harmonic current, which become a major barrier in terms of power density and cost. Sinusoidal charging method can be applied, while this might affect the charging efficiency and a deep study is still needed to further investigate on the impact to the Lithium-ion battery. An active filter auxiliary power module (AFAPM) based dual-mode dual-voltage charging system for vehicle application has been proposed. The AFAPM converter has two modes: the HV active filtering mode, in which the vehicle is connected to the grid and the converter assimilates the significant second-order harmonic current; and the low-voltage (LV) battery charging mode, in which the vehicle is running and the converter charges the LV battery from HV battery. However, a relay and inductors are still required in that converter to achieve the dual-mode operation. This paper proposes a primary full-integrated AFAPM for electrified vehicle applications with single-phase onboard chargers. The proposed AFAPM converter is composed of a two-phase bidirectional buck converter to work as an AF and a dual-active-bridge to operate as a LV battery charger auxiliary power module (APM). With the proposed converter, only an extra active energy storage capacitor is needed to achieve the active filtering. All the switches and inductors on the primary stage are shared between the AF and APM. Therefore, the use of a bulky capacitor bank or an additional AF circuit is avoided and, thus, the cost, size, and weight of the dual-voltage charging system in the electrified vehicle applications can be reduced. A 720-W prototype has been built to confirm the effectiveness of the proposed converter.

Simple realization of a third order Butterworth filter with MOS-only technique

Recently, many active filter circuits that use only MOS transistors were presented in the literature. In these circuits, instead of passive resistors, transconductances of MOSFETs operating in saturation region are used. Moreover, their parasitic gate to source capacitances are employed instead of passive capacitors. These circuits provide circuit implementation with fewer transistors and eliminate the need for external passive elements. In this study, a MOS-only third order Butterworth filter for high frequency applications has been proposed. The circuit leads to a compact circuit having fewer number of transistors compared to classical active block-based analog counterparts. Simulation results agree well with the theoretical study.

Applied Integrated Active Filter Auxiliary Power Module for Electrified Vehicles With Single-Phase Onboard Chargers

In single-phase onboard chargers for electrified vehicles, second-order harmonic currents and corresponding ripple voltages exist on the dc bus. The low-frequency harmonic current is normally filtered using a bulk film capacitor or an additional active filter (AF) circuit. This presents an obstacle for improving the power density as well as reducing the cost. This paper proposes a simple and effective method that reduces the bulk capacitor in single-phase chargers and alleviates the low-frequency sinusoidal harmonic current in automotive applications. It applies the low-voltage (LV) battery charger auxiliary power module as an AF to filter the low-frequency harmonic currents in the high-voltage (HV) battery charger when the HV battery is charging. Hence, the integrated active filter auxiliary power module (AFAPM)-based dual-voltage charging system can achieve the AF function without extra power switches, heat sinks, and corresponding gate-drive circuits. In addition, the proposed AFAPM converter can obtain an almost unchanged switch rating to achieve 2.4-kW LV battery charging and 6.6-kW HV active filtering functions. Therefore, the proposed method can reduce the cost for the dual-voltage charging system in electrified vehicles. A 1.2-kW proof-of-concept prototype has also been built and experiments show promising results confirming the effectiveness of the proposed concept.

Design and Realization of Drive Circuit for Uncooled Infrared Focal Plane Array

This paper presents a design method for drive circuit system of uncooled infrared detector of ULIS Company. On basis of theoretic analysis of uncooled infrared detector structure and demands for drive circuit, high precision regulated power supply, and second order active filter circuit are adopted to produce high precision, low noise adjustable bias voltage. Dividing frequency through FPGA, digital time sequence signal is produced to ensure the steadily and reliably of the detector. The simulation and test results indicate that the output bias voltage is consistent with the design value, and can ensure stability of the detector.

THE MECHANICAL QUANTITIES TRANSDUCERS EVOLUTION WITH THE DOMAIN-DISSIPATIVE PIEZOELECTRIC CELLS IN THE CHARTS OF THE ACTIVE HIGH-PASS FILTER

The article suggested the equivalent circuit of the inverter mechanical values with piezoelement in the scheme of the active high-pass filter with multi-loop feedback. The frequency converters transmission ratio is received. The modeling and study of the frequency response of piezoelectric transducers using computer modeling in MS9 package where performed. This bimorph according to the theory of electromechanical analogies presented by series-parallel oscillating RLC - circuit. The correspondence of computer and mathematical model of the converter real converter, which is confirmed by the coincidence of the frequency and characteristics of the amplitude. The information generated by a computer model of the frequency response transducers match the frequency response, and based on mathematical models. It was established that the non-linearity of frequency and amplitude-frequency error transducers depends on the angle between the polarization vector and the vector of the electric field of the output voltage. For drives on the basis of the modified active filter circuits treble with an increase in the angle between the polarization vector and the vector of the electric field of the output voltage from 0 to 82˚ resonant peak of the converter and the amplitude-frequency error is reduced

A FEASIBLE MEMRISTIVE CHUA'S CIRCUIT VIA BRIDGING A GENERALIZED MEMRISTOR

By bridging a generalized memristor between a passive LC oscillator and an active RC filter, a simple and feasible memristive Chua's circuit is presented. The generalized memristor without grounded limitation is equivalently achieved by a full-wave rectifier cascaded with a first-order parallel RC filter. The dynamical characteristics of the proposed circuit are investigated both theoretically and numerically, from which it can be found that the circuit has three unstable equilibrium points and demonstrates complex nonlinear phenomena. The experimental circuit is easy to implement and the measurement results validate the results of theoretical analyses.

Improvement of Power Quality by Realising Renewable Energy based Cascaded Five Level Control Power Conditioner

Renewable Energy Sources(RES) are best alternative to conventional energy source. This paper presents a Renewable energy based Shunt Active Filter circuit in conjunction with Proportional Integral (PI) and Fuzzy Logic Controller (FLC) for the power-quality improvement. In today's world the loads are highly become electronic based which produce more harmonics and EMI. The main aim of this research work is to reduce current harmonics and reactive power compensation due to the non-linear loads. This paper studies an investigation of Cascaded Five-Level Inverter (CFLI) based SAF in PS. By using CFLI the harmonics distortion can be minimized and switching losses can also be minimized as it uses minimum number of switches. Sub-Harmonics Pulse Width Modulation (SHPWM) technique with Proportional and Integral (PI) controller and D-Q reference frame theory are proposed in this paper for reactive power compensation, reducing harmonic distortion and maintaining DC capacitor voltage. The Sub-Harmonic Pulse width modulation is used for switching the switches of CFLI. The reference compensating currents for SAF are calculated by using D-Q reference frame theory and PI controller is used for capacitors dc voltage regulation for SAF. The controls are made by controlling the RES voltage level for the whole system. The results are validated through MATLAB/Simulink simulation software and TMS320F2407 DSP with SAF and without SAF.

Sistem Akuisisi Data Multiplatform Berbasis PC dengan Tampilan Hasil di Twitter

Computer or Personal Computer (PC) based data acquisition system had enabled the measurement of physical parameters, not only to display and store them in the computer but also to send them to a website. Twitter as one of web services for social media that provides the facility to display 140-character length of text status has been deemed sufficient for the purpose of displaying the latest data and is accessible through available Application Programming Interface (API). The purpose of this research is to design a PC-based data acquisition system which is capable to conduct measurement, storage and transmission of data to the web service via Twitter API. The proposed system was consisted of LM35 temperature sensor to measure room temperature, Arduino Nano microcontroller and a data acquisition application in PC to display and store data in a Comma-Separated Values (CSV) file. Based on test results for processes involving Analog to Digital Converter (ADC), the obtained error is 3.71% for voltage value and the average difference between measured values and displayed ones is 0.01 V. Average error for temperature measurement is 5.13% and the difference between measured values and the displayed ones is 1.34°C. Built application had produced an adequate display of interface and fulfilled all required functionalities. Average response time of Twitter API to Choreo is 0.18 s while average time to transmit data from application to Twitter is 2.15 s or 11.75 times longer. In later development, LM35 should be replaced with a more precise sensor. The occurrence of randomness in measurement results could be minimized by adding an active filter circuit between sensor and microcontroller.

Analog circuits fault diagnosis using multi‐valued Fisher's fuzzy decision tree (MFFDT)

SummaryFault diagnosis of analog circuits is more challenging compared with digital circuits as a result of the parametric deviation and the difficulty in signal discretization. There still lacks effective approaches to realize reliable fault detection and isolation for a comprehensive diagnosis. A new fault diagnosis technique called multi‐valued Fisher's fuzzy decision tree (MFFDT) is proposed in this paper to solve the problem. This technique uses the decision tree as the diagnosis model and incorporates the Fisher's linear discriminant principles. The fuzzification mechanism is devised to discretize the input monitoring data. The proposed MFFDT method is composed of two aspects: decision tree training and real fault diagnosis processes. The former uses the benchmark data to train a decision tree, while the latter sends the monitoring data into the decision tree to generate diagnosis results. The proposed method is validated using simulated data and the real‐time data for an active filter circuit and an audio amplifying circuit. The comparative analysis is also presented to evaluate diagnosis performances. Copyright © 2015 John Wiley & Sons, Ltd.

New Concept of PQR-Coordinate on Power Transformation for Harmonics Reducing

Power transformation of pqr-coordinate modified by Euler angle rotation method used in analysis of the IGBT active filter circuits as the instantaneous power theory is reviewed. Twice and three times rotation of Euler angle already conducted and produced a matrix transformation different from the Kim-Akagi’s model. Method of Fourier integral in the Voltage Source PWM Converter be done so a harmonics characteristic can be known and may be reduced. Value of Euler angles in frequency domain determined as a carrier harmonic waveforms. This approach is gives slightly different than that has understood so far.

Application of wavelet-based active power filter in accelerator magnet power supply

Since modern accelerators demand excellent stability to magnet power supply (PS), it is necessary to decrease harmonic currents passing magnets. Aiming at depressing the rappel current from the PS in the Beijing electron-positron collider II, a wavelet-based active power filter (APF) is proposed in this paper. An APF is an effective device to improve the quality of currents. As a countermeasure to these harmonic currents, the APF circuit generates a harmonic current, countervailing harmonic current from PS. An active power filter based on wavelet transformation is proposed. Discrete wavelet transformation is used to analyze the harmonic components in the supply current, and an active power filter circuit works according to the analysis results. Our simulation and experiment results are given to prove the effect of the APF.

A Power Sensor Tag With Interference Reduction for Electricity Monitoring of Two-Wire Household Appliances

This paper demonstrates a flexible nonintrusive power sensor tag with an interference reduction scheme for accurate electricity monitoring of the household appliances using typical SPT-2 18 AWG zip-cord power lines. Both current and voltage sensors with the design of a 50-turn inductive coil and two capacitive electrodes, respectively, in an area of 1.3 ×1 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> are fabricated on a 100- μm-thick flexible polyethylene terephthalate substrate as a sensor tag. The tag exhibits a sensitivity of 271.6 mV/A and 0.38 mV/V via active low-pass filter circuits for the current and voltage detection. A compensation circuit inputted with the signals of the voltage sensor is applied for the interference reduction of the current sensor electrically coupled with the power cord so that the current sensor can achieve over a 40-dB signal-to-noise ratio for measuring the loaded current of 1 A, 60 Hz on the power line.

Weak Signal Detection System Based on Lock-in Amplifier Technology

In order to detect the weak signal deeply buried in the noise, a weak signal detection system based on lock-in amplifier is proposed. The system includes the preamplifier circuit, active low pass filter circuit, AC amplifying circuit and phase sensitive demodulation circuit. Test results show that it can greatly increase the signal-to-noise ratio (SNR) up to 12.7db.