Order High Pass Filter Research Articles

Reduced Losses in PV Converters by Modulation of the DC Link Voltage

The efficiency of a PV system has improved by the fact that the researchers have used different techniques to enhance their efficiency. This paper aims to present how the PV converter losses can be reduced by employing a polypropylene capacitor in the DC link and to modulate that DC voltage. A problem of controllability and stability arises. Two current control methods, constant off time and a PWM type with second order high pass filter DC-link feedback are presented. Polypropylene capacitors in the PV converters do have lower losses and a lower cost. The PV converter simulation and lab experiment is based on a three-phase bridge APTGF50X60T3G, used to combine a step-up/step down and H-bridge in one package.

A fully balanced first order high-pass filter

The topic of this article is the design of a fully balanced first-order high-pass filter and its two circuits. The first circuit is a fully balanced current-tunability first-order high-pass filter consisting of four NPN transistors and a single capacitor, which is a simple design and quite compact. The pole frequency can be adjusted with a bias current. The results of the first circuit shows the phase and gain responses, the phase and gain responses when adjusted with a bias current, the time-domain response, and the harmonic spectrum. However, this circuit found a flaw in the temperature that affects the pole frequency, and total harmonic distortion is relatively high. Therefore, the second circuit improves defects by the CAPRIO technique to reduce the total harmonic distortion, and the resistors in the circuit are added to the design to replace the resistance and the effect of temperature on the properties of the transistor. This circuit consists of four NPN transistors, four resistors, and a single capacitor. The resistors in this circuit can be adjusted to change the pole frequency and voltage gain. The results of the second circuit show the gain and phase responses of the proposed circuits, the phase and gain responses when adjusted to the value of the resistor, the phase and gain responses at various temperatures, as well as their time-domain responses and total harmonic signal distortion. The all-pass filter is also made using the filter introduced in the second circuit because of its voltage gain-adjustable property. So, if the suggested circuit is constructed in combination with a buffer circuit to make it feasible to function as an all-pass filter, the result will be an all-pass filter. In accordance with the results of this study, we have introduced a design for a high-pass filter to reduce total harmonic distortion and the effect of temperature

A resonant damping control and analysis for LCL-type grid-connected inverter

The inverter becomes an essential part in the distributed energy units, where an inductor–capacitor–inductor (LCL) filter is an up-to-date adoption for grid interfacing. However, the challenging issue of resonance related to the LCL-filter worsens the dynamic control characteristics and produces stability threat for the voltage source inverter system. The proper design of inverter control plays a substantial part in ensuring a steady state operation and a high quality of grid injected current according to grid connection codes. This paper offers a different design method of inverter control which alters the inner damping loop structure to enhance the damping and stability features of the inverter system. In the proposed solution, a modified compensator is employed through the LCL filter network and filter capacitor current feedback loop, the resultant augmented plant’s output is then sent back at the reference point of a grid-connected inverter system to damp the unwanted resonance spike. This particular arrangement to form a damping loop is termed as parallel feedforward compensation. The damping loop is implemented by calculating the filter capacitor current, and a first order high-pass filter is employed as a damper in the suggested arrangement. Moreover, for comparative studies and analysis, the conventional filter capacitor current feedback active damping method is selected. In addition, the stability margins and control performance of the open current loop are examined under different filter parameters values. The substantial results of the suggested structure are quicker dynamic response, comparatively improved resonance damping, better tracking performance and higher delay compensation capability. A laboratory prototype is established to confirm the effectiveness of the suggested scheme on the bases of control performance and stability margins.

Frequency Response of Electronically Tunable Current-Mode Third Order High Pass and Low Pass Filter for Q = 10

The circuits using current-mode (CM) building blocks have received considerable attention in many filtering and signal processing applications. Compared to their voltage-mode(VM) counterparts, the current-mode building blocks are attractive because of their wider bandwidth, higher slew rate, and lower power consumptions. In IC technology, it is desirable to operate circuits at low voltages which can be achieved by using CM building blocks. As a large number of op-amp based circuits with elegant realization procedures are already available, it is worthwhile to convert them into the circuits based on current-mode building blocks. In this paper, a realization of a current mode third order high pass and low pass filter is described. The proposed circuit employs operational amplifier as the basic building unit. The filter circuit realizes quadratic work function. It provides electronically tuning capability of the filter characteristics. The proposed circuit works ideal for Center frequency fo= 10 k and Circuit merit factor Q > 1. The gain roll-off this configuration is 18dB/octave. The circuit is suitable for monolithic integration and high frequency operation. The filters developed were successful in obtaining passive sensitivities less than unity in magnitude and active sensitivities are half in magnitude, which is a noteworthy achievement. The circuit is suitable for high frequency operation and monolithic integration.

On the removal of the open earcanal high-pass filter effect due to its occlusion: A bone-conduction occlusion effect theory

The occlusion effect is commonly experienced by in-ear device wearers as an increased loudness sensation of bone-conducted low frequency sounds. A widespread theory proposed by Tonndorf and based on a simplified electro-acoustic model describes the phenomenon as the removal of the open earcanal high-pass filter effect due to a perfect or partial occlusion. However, this filter has not been clearly defined and several ambiguities remain. Revisiting the model, a second order high-pass filter effect for the volume velocity transferred between the earcanal wall and the eardrum is highlighted. This filter remains for partial occlusion but vanishes for perfect occlusion. In the latter case, the volume velocity transferred from the earcanal cavity to the middle ear through the eardrum drastically increases, which explains the predominance of the occluded outer ear pathway on the hearing by bone-conduction at low frequencies.

Fully Analog ECG Baseline Wander Tracking and Removal Circuitry using HPF Based R-peak Detection and Quadratic Interpolation

This work presents a fully analog baseline wander tracking and removal circuitry using high-pass filter (HPF) based R-peak detection and quadratic interpolation that does not require digital post processing, thus suitable for compact and low power long-term ECG monitoring devices. The proposed method can effectively track and remove baseline wander in ECG waveforms corrupted by various motion artifacts, whereas minimizing the loss of essential features including the QRS-Complex. The key component for tracking the baseline wander is down sampling the moving average of the corrupted ECG waveform followed by quadratic interpolation, where the R-peak samples that distort the baseline tracking are excluded from the moving average by using a HPF based approach. The proposed circuit is designed using CMOS 0.18-μm technology (1.8V supply) with power consumption of 19.1 μW and estimated area of 15.5 mm² using a 4^th order HPF and quadratic interpolation. Results show SNR improvement of 10 dB after removing the baseline wander from the corrupted ECG waveform.

A Multifunctional Voltage Mode Fractional Order Filters using a Single CFOA

A multifunction voltage mode fractional order filter structure is described using a single current feedback operational amplifier (CFOA). This configuration realizes three fractional order filters (FOFs) namely fractional order low pass (FOLP), fractional order band pass (FOBP) and fractional order high pass (FOHP) filters. The performance of the proposed structure has been verified through PSPICE and MATLAB simulation results using macro model of AD844 type CFOA.

Realization with Fabrication of Double-Gate MOSFET Based Third Order High Pass Filter

This research work designs a third order high pass filter with the replacement of traditional MOSFET and amplifiers with Double-Gate (DG) MOSFET. A theoretical background for the fundamental concepts involved has been analysed. A mathematical analysis of circuit designs based on the fundamental concepts has conducted, simulated and finally fabricated. The objective of this research work is to improve the filter specifications via application of DG MOSFETs. The system is to be designed for corner frequency fc = 10 kHz, the gain >= unity. The components in the stopband (f < 0.01fc) have at least -20 dB attenuation with the bandwidth greater than 1.5 MHz.

A Mathematical Framework for Modelling of Current Source Converter Based High Voltage DC Transmission Systems

Transmission of electrical power through High Voltage Direct Current (HVDC) has attracted the attention of several researchers in the recent years. To investigate the performance of HVDC transmission systems, a complete linear mathematical model is required. In this paper, a well-developed linear continuous model of current source converter based twelve pulse HVDC transmission systems is presented. In which, the converter AC system is represented by damped LLR equivalents at fundamental frequency and at the third harmonic. Also, they are equipped with double tuned harmonic filter and second order high pass filter to suppress the AC harmonics and a capacitor for reactive power compensation. The DC system is secured with rectifier current control, inverter current control, inverter voltage control and inverter extinction angle control. The HVDC transmission system model is implemented in the MATLAB/Simulink environment and the performance of the system has been investigated by observing the rectifier side AC quantities, rectifier DC quantities, inverter side AC quantities and inverter DC quantities.

Harmonic mitigation for power rectifier using passive filter combination

Power rectifiers are widely used in different industrial applications that deliver DC voltage supply for many types of loads like electrolysis cells, metal electroplating and other DC loads. These rectifiers act as nonlinear loads injecting harmonic currents to the AC mains with lots of troubles and negative impact on the utility grid and the load itself, like increasing losses, measurement error, protection device false tripping and distortion of the voltage at the PCC affecting other loads at the same point. For this reason, many researches focus on this problem and how to mitigate it. In this research, power analysis measurements are taken for 750 KW power rectifier feeding electrolysis cells and define the power quality indices compared to IEC 519 Standard. Passive filter is selected to mitigate the recorded harmonics. Two types of filters are designed. The first is three single tuned passive filter to mitigate the 5th, 7th and the 11th harmonics. The second type is 2nd order high pass filter to mitigate harmonics equal and greater than 13th harmonics. MATLAB simulation is performed to validate the proposed solution. The current total harmonic distortion can be reduced from 29.6 % to 1.5 % and supply voltage total harmonic distortion is also improved from 3.25 % to 0.62% which meet the international standard and improve the power quality of the voltage at point of common coupling.

Electronically controlled voltage mode first order multifunction filter using low-voltage low-power bulk-driven OTAs

In this paper, a new versatile voltage mode first order filter using low-voltage low-power bulk-driven OTAs is presented. The proposed filter with two high impedance input-voltage nodes and single output-voltage node consists of two OTAs, one grounded capacitor and one grounded resistor. Three filtering responses, low-pass (LP), high-pass (HP) and all-pass (AP) are obtained by appropriately applying the input signal into the input nodes. The natural frequency (ω0) can be electronically tuned by the bias current. In case of all-pass filter, its phase response is electronically controlled by adjusting only single bias current. With this feature, it doesn’t need to simultaneously change two bias currents or two passive element values. The performances of the proposed filter were evaluated via PSPICE simulations using CMOS 0.18 μm TSMC technology parameters (level 7) with ±0.4 V supply voltages. The proposed filter consumes 47.2 μW. To obtain the actual testing results, the proposed filter was also experimented using commercially available IC, LM13700. Moreover, the three phases sinusoidal oscillator based on proposed first order high-pass filter was designed and investigated by PSPICE simulation and experiment.

Fractional Order High Pass Filter Based on Operational Transresistance Amplifier with Three Fractional Capacitors of Different Order

Design, realization and performance evaluation of fractional order high pass filter based on Operational Transresistance Amplifier (OTRA) using three fractional elements of different order α, β, γ are presented in this paper. The projected circuit uses a single active current mode device i.e. OTRA and utilizes fractional capacitors of varying orders to boost the design flexibility. The design equations for fractional order high pass filter are computed from the transfer function. The paper elaborates the impact of fractional order elements of varying order on the frequency response of the filter. Subsequently, the sensitivity and stability of the transfer function of the proposed filter are also analyzed. The potential usefulness of the proposed filter is additionally incontestable through the Total Harmonic Distortion (THD), Power Supply Rejection Ratio (PSRR), Temperature sweep, Corner, Supply Voltage variation and Noise Analysis. It has been observed that the proposed pass filter in fractional domain supported OTRA provides greater flexibility in controlling the magnitude characteristics.

Fractional-Order Modeling and Identification for a Phantom EEG System

This paper is about dynamical modeling of an electroencephalographic (EEG) measurement chain. It is based on a home-made experimental setup consisting of an electrolytic medium, stimulated by external electrodes, the activity of which is measured at different points via other electrodes, connected to an EEG recording device. A novel noninteger-order model structure is then established with a so-called constant phase element, and a Nyquist-based graphical method is derived to identify the noninteger order. The study is completed with a recursive identification method for full parameter estimation in the model, and various applications on experimental data are presented, finally resulting in a fully identified noninteger order high-pass filter.

DESIGN OF SECOND ORDER BUTTERWORTH HIGHPASS FILTER USING CMOS TECHNOLOGY

The research Complementary Metal-Oxide Semiconductor (CMOS) Technology for Design of second order butterworth highpass filter IC. This is caused CMOS have excellence low power dissipation and small size. This research aims to know performance, quality and reliability second order butterworth highpass filter circuit. The method used to problem solving, analysis with the literature and the simulation use pspice program for exam the specification of circuit. To make IC picture using DSCH software and layout circuit using Microwind program. From examination result -2,99dB for gain voltage parameter, frequency -40dB and 88,25° phase shift second order highpass filter. The result of this circuit have low power dissipation although applied to second order highpass filter equal 2,28mW better than generality IC second order highpass filter (GH580). Wide of layout circuit is 1110µm x 385µm DOI : https://doi.org/10.26905/jeemecs.v1i1.2299

Maximum power point tracking with fractional order high pass filter for proton exchange membrane fuel cell

Proton exchange membrane fuel cell U+0028 PEMFC U+0029 is widely recognized as a potentially renewable and green energy source based on hydrogen. Maximum power point tracking U+0028 MPPT U+0029 is one of the most important working conditions to be considered. In order to improve the performance such as convergence and robustness under disturbance and uncertainty, a fractional order high pass filter U+0028 FOHPF U+0029 is applied for the MPPT controller design based on the traditional extremum seeking control U+0028 ESC U+0029. The controller is designed with integerorder integrator U+0028 IO-I U+0029 and low pass filter U+0028 IO-LPF U+0029 together with fractional order high pass filter U+0028 FOHPF U+0029, by substituting the normal HPF in the original ESC system. With this FOHPF ESC, better convergence and smoother performance are achieved while maintaining the robust specifications. First, tracking stability is discussed under the commensurate-order condition. Then, simulation results are included to validate the proposed new FOHPF ESC scheme under disturbance. Finally, comparison results between FOHPF ESC and the traditional ESC method are also provided.

Improved Stator Flux Estimation for Direct Torque Control of Induction Motor Drives

&lt;p&gt;Stator flux estimation using voltage model is basically the integration of the induced stator back electromotive force (emf) signal. In practical implementation the pure integration is replaced by a low pass filter to avoid the DC drift and saturation problems at the integrator output because of the initial condition error and the inevitable DC components in the back emf signal. However, the low pass filter introduces errors in the estimated stator flux which are significant at frequencies near or lower than the cutoff frequency. Also the DC components in the back emf signal are amplified at the low pass filter output by a factor equals to . Therefore, different integration algorithms have been proposed to improve the stator flux estimation at steady state and transient conditions. In this paper a new algorithm for stator flux estimation is proposed for direct torque control (DTC) of induction motor drives. The proposed algorithm is composed of a second order high pass filter and an integrator which can effectively eliminates the effect of the error initial condition and the DC components. The amplitude and phase errors compensation algorithm is selected such that the steady state frequency response amplitude and phase angle are equivalent to that of the pure integrator and the multiplication and division by stator frequency are avoided. Also the cutoff frequency selection is improved; even small value can filter out the DC components in the back emf signal. The simulation results show the improved performance of the induction motor direct torque control drive with the proposed stator flux estimation algorithm. The simulation results are verified by the experimental results.&lt;/p&gt;

Improving Efficiency of NPP Software Based I&amp;C

The paper considers improving efficiency of NPP software based I&amp;C during adjustment and readjustment of its characteristics. The research analyzes impact of transfer function coefficient of digital components on features of frequency-response characteristics, which shall be considered during design of software based I&amp;C. The paper objective was to determine the numerator and denominator dependencies of transfer function of first order high-pass and low-pass digital filters of cut-off frequency, and also to determine dependencies on pulsation coefficient.

An efficient differential evolution with wavelet mutation algorithm for optimal IIR filter design

In this paper, an improved version of differential evolution (DE) algorithm which incorporates wavelet-based mutation strategy called differential evolution with wavelet mutation (DEWM) is proposed for the design of digital infinite impulse response (IIR) filters. Unlike fixed value of scaling factor in standard DE, the proposed optimisation technique DEWM adopts iteration dependent scaling factor governed by the wavelet function during the mutation process. This modification in the mutation process not only ensures the faster searching in the multidimensional search space but also the solution produced is very close to the global optimal solution. The effectiveness of this algorithm is justified with a comparative study of some well established algorithms, namely, real coded genetic algorithm (RGA), conventional particle swarm optimisation (PSO) and standard DE with a superior DEWM-based outcome for the designed 8th order IIR low pass (LP), high pass (HP), band pass (BP) and band stop (BS) filters. Simulation results affirm that the proposed DEWM algorithm outperforms its counterparts not only in terms of quality output, i.e., sharpness at cut-off, pass band ripple and stop band attenuation but also in convergence speed with assured stability.

Reduced Losses in PV Converters by Modulation of the DC Link Voltage

The efficiency of PV systems has improved by the fact that the researchers have used different techniques to increase their technical capabilities. This paper aims to present how the PV converter losses can be reduced by employing a polypropylene capacitor in the DC link and to modulate that DC voltage. This modification leads to problems with controllability and stability. In order to solve them two current control methods are presented - constant off time and a PWM type with second order high pass filter DC-link feedback. PV converters that utilize polypropylene capacitors do have lower losses and have lower cost. The PV converter simulation in Matlab SimulinkTM and lab experiment, presented in this paper, are based on a three-phase bridge APTGF50X60T3G, used to combine a step-up/step down and H-bridge in one package.

Frequency Response Improvement for Inertial Magnetoelectric Velocity Sensor Using Frequency-Selected Compensation Network

The inertial magnetoelectric velocity sensor is widely used in the fields of vibration control and measurement. The frequency response in the low frequency range is, however, limited by high frequency resonance because of the characteristic of second order high pass filter of the structure. A frequency-selected network for amplitude-frequency characteristic compensation to improve the performance of the frequency response is presented. The frequency-selected network, which is composed of amplifiers, resistors, and capacitances, is connected to the output port of the sensor in cascade without any modification of the sensor's structure. After compensation, the frequency band of the sensor is flattened and frequency response still has the characteristic of second order high pass filter, whereas the resonant frequency decreases from ~ 10 to 0.93 Hz. Meanwhile, it keeps the transducer in small size and light weight. The experimental results have shown that the sensor after been compensated has good performance in the low frequency range.