Showing papers on "Electronic filter published in 2019"

Power Quality Management of PV Power Plant With Transformer Integrated Filtering Method

Abstract: This paper presents a new solution of power quality management for the photovoltaic (PV) power plant with the transformer integrated filtering method. The innovation of the PV power plant is that it contains two-stage filtering station, which consists of a box-type transformer with integrated filter and a 110 kV grid-connected transformer based on inductive filtering method. The filtering reactor can be integrated into the box-type transformer as a decoupled winding, so that the modular design of the box-type transformer and the passive filter is realized. Inductive filtering method applied in the grid-connected transformer not only improves the power quality at the point of common coupling, but dampens the harmonic resonance between the passive filter and grid. The hierarchical structure of the PV power plant is introduced firstly. Then, the equivalent circuit model and the mathematical model of the primary and secondary filtering stations are established, respectively. Moreover, the influence of the weak coupling of integrated reactor on the filtering performance is analyzed. The antijamming capabilities of the inductive filtering method and the traditional filtering method are compared under the condition of parameter disturbance. At last, the site tests of the PV power plant with transformer integrated filtering method are made, which show that the PV grid-connected system comprised of the two-stage filtering station has the characteristics of low harmonic emission, high power factor, and stable operation.

Adaptive fuzzy-neural-network based on RBFNN control for active power filter

Abstract: In this paper, an adaptive fuzzy-neural-network (FNN) control scheme based on a radial basis function (RBF) neural network (NN) is proposed to enhance the performance of a shunt active power filter (APF). APF can efficiently eliminate harmonic contamination and improve the power factor compared with traditional passive filter. The proposed approach gives a RBF NN control scheme, which is utilized on the approximation of a nonlinear function in APF dynamic model, the weights of the RBF NN are adjusted online according to adaptive law from the Lyapunov stability analysis. In addition, adaptive fuzzy-neural-network systems is employed to compensate the neural approximation error and eliminate the existing chattering, enhancing the robust performance of the system. Simulation results confirm the effectiveness of the proposed controller, demonstrating that APF with the proposed method has strong robustness and the outstanding compensation performance.

Active EMI Filter Design With a Modified LCL-LC Filter for Single-Phase Grid-Connected Inverter in Vehicle-to-Grid Application

Abstract: More and more attention has been gained in the vehicle-to-grid (V2G) system due to its attractive features, such as transferring bidirectional power between electric vehicles and grid, regulating grid voltage/frequency. This paper develops the active electromagnetic interference (EMI) filter (AEF) with significant system volume and weight reduction compared to the traditional passive EMI filter (PEF). While the high-frequency parasitic parameters of the AEF and the restricted loop gain result in limited AEF EMI noise attenuation in the high-frequency range. Thus, an additional passive EMI filter is commonly needed to suppress the EMI noise. For avoiding external passive filter components, the active EMI filter is designed and integrated with a modified LCL-LC filter as a hybrid filter to guarantee EMI noise attenuation. The modified LCL-LC filter can maintain satisfactory harmonic suppression with a higher EMI reduction ability compared to other types of harmonic filters. Based on a single-phase grid-connected inverter, the total harmonic distortion (THD) and the conducted EMI measurement results are compared with the results of traditional LCL, LLCL, LCL-LC filters. The effectiveness of the proposed circuit is verified by simulation and experimental results. The proposed circuit successfully improves the filter design of the inverter in the suppression of harmonics and EMI noise.

A Nanopower Biopotential Lowpass Filter Using Subthreshold Current-Reuse Biquads With Bulk Effect Self-Neutralization

Abstract: A nanopower CMOS 4th-order lowpass filter suitable for biomedical applications is presented. The filter is formed by cascading two types of subthreshold current-reuse biquadratic cell. Each proposed cell is capable of neutralizing the bulk effect that induces the passband attenuation. The nearly 0-dB passband gain can thus be maintained, while the entire filter circuit remains compact and power-efficient. Designed for electrocardiogram detection as an example of application, the filter prototype has been fabricated in a 0.35 $\mu \text{m}$ CMOS process occupying 269 $\mu \text{m}\,\,\times $ 383 $\mu \text{m}$ chip area. Measurements verify that the filter can operate from a 1.5-V single supply and consumes 5.25 nW, while providing a cutoff frequency of 100 Hz and input-referred noise of $39.38~\mu \text{V}_{\mathrm {rms}}$ . The intermodulation-free dynamic range of 51.48 dB is obtained from a two-tone test of 50 and 60 Hz input frequencies. Compared with state-of-the-art nanopower lowpass filters using the most relevant and reasonable figure of merit, the proposed filter ranks the best.

Compact Wide-Frequency Tunable Filter With Switchable Bandpass and Bandstop Frequency Response

Abstract: In this paper, a novel compact wide-frequency tunable filter with switchable bandpass and bandstop frequency response is presented. By employing two PIN diodes between the source and load port, the bandpass and bandstop filtering response can be switched, respectively. Three varactor diodes have been used to tuning the operating frequency of the tunable filter at bandpass and bandstop frequency response. The even- and odd-mode method is applied to analyze the presented tunable filter. When PIN diode is forward-biased, the filter has the bandstop response, and the filter has bandpass response while it is reversed. To verify the proposed tunable filter circuits, the tunable bandpass filter and bandstop filter are designed, fabricated, and measured. It is demonstrated that the center frequency of the fabricated tunable filter is tuned from 0.95 to 1.35 GHz. The measured insertion loss in the band is greater than 13 and 11 dB for bandstop mode and bandpass mode, respectively. Moreover, the fabricated tunable filter has a compact size of 0.24λ g × 0.24λ g (λ g is the wavelength of the center frequency during the tunable frequency range).

0.5 V sixth-order Chebyshev band-pass filter based on multiple-input bulk-driven OTA

Abstract: This paper presents a low-voltage sixth-order Chebyshev band-pass filter based on multiple-input operational transconductance amplifier (MI-OTA). The used voltage supply is 0.5 V and the filter employs six MI-OTAs and six capacitors. The third intermodulation distortion (3rd IMD) is below 1% for input sine wave signal with peak-to-peak up to rail-to-rail while the dynamic range (DR) is 66.8 dB. In order to insure low-voltage operation capability, extended linear range, increased voltage gain of the MI-OTA, the multiple-input bulk-driven transistor (MIBD) along with self-cascode techniques have been used. As a result, the proposed MI-OTA based on MIBD is capable to work with 0.5 V supply voltage and consumes power in the range of (2.5–1.2E3) nW for tunable bias current in the range from 1 nA to 500 nA. The MI-OTA and the filter circuits were designed and simulated in Cadence/Spectre environment using 0.18 µm CMOS process from TSMC. The simulation results agree well with theory and confirm the filter functionality.

Extending the Autonomy of a Battery for Electric Motorcycles

Abstract: Electric motorcycles use a battery storage system and a controlled inverter (motor drive) to drive the wheels. Given that the sale of electric motorcycles is expected to grow significantly over the next decade, the aim of this research is to add a supercapacitor storage system to this simple network in order to extend the autonomy of the motorcycle. This paper analyzes and demonstrates the benefits of two different structures for adding a supercapacitor bank to a lithium-ion battery pack: a passive filter and a buffer for the battery. The advantages of each structure are presented and design guidelines are provided. In addition, we propose a synthetic inductor filter typology based on the two analyzed structures in order to increase the autonomy of the motorcycle. Simulations and experimental results using real data validate the analysis. This paper then uses real data extracted from an electric motorcycle to compare the four topologies: batteries only, the passive filter, the buffer, and the synthetic inductor semi-active hybrid storage system. The comparison shows that battery capacity is extended up to 7.8% with a smoother current profile. However, due to the losses from the added converter in cascade, the net capacity of the whole system is extended only up to 3.7%. Therefore, improvements in the dc/dc converter can further increase the entire system capacity.

Mixed-Integer Distributed Ant Colony Multi-Objective Optimization of Single-Tuned Passive Harmonic Filter Parameters

Abstract: The extended ant colony known as the Mixed Integer Distributed Ant Colony Optimization (MIDACO) is presented in this paper as a new application of solving multi-objective single-tuned passive filters design problems. This paper presents a new non-dominated solution for the optimization of four independent objective functions which are maximized power factor, minimized total harmonic voltage distortion, minimized total demand distortion, and minimized investment cost of the filter. The global solution is achieved by maintaining the quality factor of the filter in a specified range, avoiding the harmonic resonance and maintaining the capacitor's capability limits within the standard limits. The attained parameters of the filter are used to weigh the performance of the system, and the robustness of the proposed algorithm is verified by comparing the results with three different highly competitive evolutionary techniques. Also, the proposed algorithm attains the Pareto front of the problem and tolerates the selection of its parameters to the most effective solution. The numerical results specify the comprehensive passive filter design through possible multi-objective approaches, and the improvements of multi-objective over single-objective optimization are also presented in this paper.

Analysis and Control of Input-Parallel Output-Series Based Combined DC/DC Converter With Modified Connection in Output Filter Circuit

Abstract: Input-parallel output-series (IPOS)-based combined converter is usually used in the situation with low input voltage and high output voltage to satisfy the requirements in switch voltage stress reduction and power expansion. In such a system, the voltage balance of filter capacitor in the output side or current sharing in the input side usually used to guarantee the control performance of the conversion system. In this paper, a phase-shifted full bridge (PSFB)-based IPOS converter with modified connection of output filter circuit used for the wide variation of input voltage is proposed, which is beneficial to reduce ripple current of filter inductor significantly. A control scheme using the same phase shifting for the two different modules of this IPOS converter is detailedly investigated with both steady state and small signal model-based analysis, it manifests that special voltage balance and current sharing control scheme are not necessary for IPOS system under the common phase shifting control method. And the small signal transfer functions of this topology used for dual loop control system design are also developed. The simulation and experiment results are presented to validate the analysis and control scheme.

Active source current filtering to minimize the DC-link capacitor in switched reluctance drives

Abstract: Switched reluctance machines receive increased attention from the automotive industry because of their cost efficiency. However, the independent phase excitation and the resulting current reversal demand comparatively large dc-link capacitors to meet the requirements regarding the ripple on the dc-link voltage and current. This paper validates the effects of the usage of a dc-dc boost converter to reduce the size of the dc-link capacitor by actively filtering the source current. The active filter is compared with the state-of-the-art topology and a passive filter. The investigations show that the active filter is able to reduce the dc-link capacitance by 80%. The dc-dc converter also provides the feature of adjusting the inverter dc-link voltage level independently from the battery voltage level. The positive effect of this additional degree of freedom on the machine efficiency is investigated and due to this feature the total efficiency of the electrical drive train remains nearly unchanged despite the extra losses in the dc-dc converter. All presented results are based on detailed simulations and experimentally validated with a 20 kW switched reluctance generator.

Single-Phase Multicell AC–DC Converter With Optimized Controller and Passive Filter Parameters

Abstract: This paper presents a novel single-phase multicell converter for ac–dc power conversion, which is formed by a series connection of several full-bridge converter stages through passive components. The proposed topology employs a simple control scheme based on the carrier-based sinusoidal pulsewidth modulation technique. Detailed design procedure of the passive filter components are analyzed and discussed. An efficient optimization method based on a differential evolution algorithm is utilized to optimize the filter parameters. Considering the filter structure, active damping is introduced in the control scheme to improve the stability of the overall system, which is later verified by experiments. The systematic design approach of the controller parameter is also highlighted, focusing a specific set of goals. Experimental results for a 1-kW prototype are presented to further validate the concept.

A Four-Winding Inductive Filtering Transformer to Enhance Power Quality in a High-Voltage Distribution Network Supplying Nonlinear Loads

Abstract: This paper solves the problem of reactive power and harmonics compensation in a high-voltage (HV) distribution network supplying nonlinear loads. An inductive filtering (IF) approach where passive filters connect to the filtering winding of a four-winding inductive filtering transformer (FW-IFT) is presented to enhance the power quality of the public grid. This method can not only greatly suppress harmonic currents of the medium and/or low-voltage (LV) side, but also prevent them from flowing into the public grid. The new main circuit topology, where the FW-IFT has specific filtering winding by adopting the ampere-turn balance of the transformer, is presented. On the basis of the structure of the FW-IFT, the magnetic potential balanced equation and inductive filtering technology, its equivalent circuit and mathematical model are established, and the filtering performances are analyzed in detail. Simulation and experimental results rated at SN-10/0.38 of the FW-IFT are presented to prove the efficacy of the comprehensive enhancement of power quality on the grid side.

Reduction in controlled power switches for a single-phase novel multilevel inverter

Abstract: Multilevel inverter (MLI) generates stepped voltage with appropriate switching combination of power devices, thus restraining the requirement of filter circuit for an efficient power conversion. ML...

Higher order lumped element absorptive low-pass and bandpass filter structures

Abstract: Here, the authors present a class of lumped-element low-pass and bandpass absorptive filter circuits. To begin with, the authors discuss a new type of absorptive low-pass filter (LPF) structure that has an excellent impedance matching performance in both passband and stopband. This work provides low-pass prototype values for the proposed absorptive LPFs in terms of those for the conventional reflective filters, namely g -parameters, so that the new type of absorptive LPF can be designed in a straightforward manner. In addition, it is shown that traditional low-pass-to-bandpass frequency transformations can be applied to the absorptive low-pass prototype cases in the design of absorptive bandpass filters (BPFs). Second- and third-order LPF and BPFs are designed and measured to verify the new type of absorptive filter and its design method.

The modeling of the transverse mode in TC-SAW using SiO2/LiNbO3 structure

Abstract: The temperature-compensated surface acoustic waves (TC-SAW) have been developed to fulfill tight roll-off requirements for recent mobile communication systems. Use of the Rayleigh SAW on SiO2-overlay/LiNbO3 substrate structure is one of the most promising techniques for the purpose. Currently, SAW device designs are done entirely through computer simulation, and their accuracy significantly impacts achievable device performance. The coupling of modes (COM) model is widely used for the acoustic simulation and its applicability is well recognized. This paper proposes a simple simulation model based on COM model for the transverse mode behaviors in the TC-SAW devices and applied to the device design. Double mode saw filter and ladder type filter are optimized with the proposed model. Optimized structure is applied to the development of the 1.6 × 1.2 mm2 sized duplexer for LTE Band 8. Smooth passband characteristics with less transverse modes responses are achieved by using the proposed method.

Recent Developments in Harmonic Resonance Detection in Low Voltage Networks using Impedance Measurement Techniques

Abstract: Harmonic resonance is a modern-age power quality issue. These issues are observed in public Low Voltage networks caused by increased penetration of diverse power electronic equipment using grid-side filter circuits and shunt capacitances. Harmonic resonance could result in stability issues or amplified harmonic levels in the network. The paper presents simulation results to emphasize on the importance on harmonic resonance. Further, the paper also provides a comprehensive survey on network harmonic impedance measurement techniques with their application towards harmonic resonance detection.

Working environment detection system

Abstract: The invention discloses a working environment detection system. The system comprises a smoke signal collection signal, a feedback calibration circuit and an operational amplifier output circuit; the smoke signal collection circuit adopts a smoke signal collector J1 in the model of LB-70C to collect a plant working environment smoke signal; the feedback calibration circuit is divided into two pathsto receive output signals of the smoke signal collection circuit; in one path, a composite circuit is composed of an inductor L1, a resistor R5 and a capacitor C3 so as to filter high-frequency noisein the signal, and a peak detection circuit is composed of an operational amplifier AR2, the operational amplifier AR4 and a diode D3 and the diode D4 to regulate signal peak value; in the second path, a delay circuit is composed of a triode Q1, a resistor R6 and a capacitor C2 to delay the signal, and the operational amplifier output circuit amplifies the signal through an in-phase manner by applying the operational amplifier AR7, and a pai type filter circuit is composed of the inductor L2, the capacitor C7 and the capacitor C8 to filter and output the signal; the smoke status in the working environment of the plant can be monitored in real time, the signal transmission stability is improved at the same time, and the signal frequency hopping and distortion are prevented.

Evaluation of Series and Parallel Hybrid Filters Applied to Hot Strip Mills With Cycloconverters

Abstract: This article presents two hybrid filter topologies applied to a hot strip mill electrical system with cycloconverters, to evaluate the harmonic compensation and damping of harmonic resonance. In addition, an evaluation of the performance of hybrid filters in reducing the current rating of the passive filter is also presented. The most relevant waveforms of the system and its harmonic spectrum are analyzed, to assess the performance of each filtering structure in improving the power quality. The results obtained through digital simulation show that a series hybrid filter provides harmonic damping and allows enhancing the harmonic compensation characteristics of the passive filtering system, using an active filter of lower rated power compared to a parallel hybrid filter. However, the series hybrid filter does not present good filtering characteristics in the high-frequency range, that can be performed by a parallel hybrid filter with a higher rating.

Reactive power and harmonic compensation : a case study for the coal-mining industry

Abstract: This study reports on a case study in Grootegeluk Mine: Exxaro Coal, Lephalale, South Africa, in terms of power factor correction (PFC), load flow, harmonic frequency scans and harmonic voltage distortion analyses. The DIgSilent PowerFactory software was used for network simulations. Harmonic and reactive power compensation techniques were compared in terms of filter type evolution and technology advancement, with the use of simple trade-off criteria such as cost-effectiveness versus performance. It was found that both passive and hybrid filters were more favourable and could effectively compensate all voltage and current harmonics and reactive power for large nonlinear loads. The installation of switched PFC filter banks tuned at the fifth harmonic order accommodates future network growth and this solution can be rolled out to any mining industry as a benchmark to lower energy cost and maximise savings achievable on the electricity bill.

Design, Simulation and Hardware Implementation of Shunt Hybrid Compensator Using Synchronous Rotating Reference Frame (SRRF)-Based Control Technique

Abstract: This paper deals with the design, simulation, and implementation of shunt hybrid compensator to maintain the power quality in three-phase distribution networks feeding different types balanced and unbalanced nonlinear loads. The configuration of the compensator consists of a selective harmonic elimination passive filter, a series-connected conventional six-pulse IGBT inverter, acting as the active filter terminated with a DC link capacitor. The theory and modelling of the compensator based on current harmonic components at the load end and their decomposition in d-q axis frame of reference are utilized in the reference current generation algorithm. Accordingly, the source current waveform is made to follow the reference current waveform using a high-frequency, carrier-based controller. Further, this inner current control loop is supported by a slower outer voltage control loop for sustaining desirable DC link voltage. Performance of the compensator is evaluated through MATLAB simulation covering different types of loads and reduction of harmonic currents and THD at the supply side along with excellent regulation of DC link voltage are confirmed. The performance of a hybrid compensator designed and fabricated using the above principles is evaluated and corroborated with the simulation results.

An intelligent low-temperature grain storage system signal calibration circuit

Abstract: The invention discloses a signal calibration circuit of an intelligent low-temperature grain storage system. The device comprises a frequency acquisition circuit 1,a frequency acquisition circuit 2, afrequency modulation and amplitude modulation circuit and a filtering output circuit, the frequency acquisition circuit 1 and the frequency acquisition circuit 2 are used for respectively acquiring signal frequencies in an input end of a signal transmission channel for a control terminal to receive signals in the intelligent low-temperature grain storage system; the frequency modulation and amplitude modulation circuit uses a triode Q1 and a resistor R5; the capacitor C2 forms a delay circuit to divide the signal into two paths of signals; the filtering output circuit uses an inductor L2 anda capacitor C13; the capacitor C14 forms a filter circuit to be filtered and then output, namely a compensation signal of a signal in the input end of a signal transmission channel for receiving the signal by a control terminal in the intelligent low-temperature grain storage system, the signal in the signal transmission channel for receiving the signal by the control terminal in the intelligent low-temperature grain storage system can be automatically subjected to frequency modulation and calibration, and signal distortion is prevented.

Household video monitoring system

Abstract: The invention discloses a household video monitoring system. The system comprises a frequency acquisition circuit 1, a frequency acquisition circuit 2, a rectification calibration circuit and a filtering output circuit. The frequency acquisition circuit 1 and the frequency acquisition circuit 2 respectively acquire analog signals at the input end and the output end of a signal transmission channelin a control terminal of the household video monitoring system. The rectification calibration circuit uses a variable resistor RW1, a capacitor C4, and a capacitor C3 to form a rectifying circuit torectify the signal, and uses a diode D6-diode D9 and an amplifier AR1 to form a composite circuit for signal limiting, amplification, and limiting processing. The frequency acquisition circuit 2 usesthe op amp AR2-AR4 and the capacitor C14 to form a loss compensation circuit to compensate the output signal of the rectification and calibration circuit. Finally, the filter output circuit uses the inductor L2, the capacitor C10, and the capacitor C11 to form a [pi]-type filter circuit. The filtered output can convert the signal frequency into a compensation signal of the signal at the output endof the signal transmission channel in the control terminal of the home video monitoring system.

Vertically-integrated differential filtering patch antenna excited by a balun bandpass filter

Abstract: This study develops a differential-fed filtering patch antenna, which features superior frequency selectivity, compact size, low cross-polarisation, and symmetrical radiation patterns. The proposed antenna consists of a rectangular patch on the top layer, which is differentially fed by a balun bandpass filter on the bottom layer. A pair of rectangular coupling slots were etched on the middle layer for energy coupling. The patch antenna performs not only as the radiator but also as the last resonator of the whole filter circuit for compactness. A prototype of the proposed filtering antenna operating at 2.45 GHz was fabricated and tested. The measured in-band peak gain is 5.9 dBi with steep roll-off at band edges, and the out-of-band gain is less than - 25 dBi. Moreover, symmetrical radiation patterns and low cross-polarisation levels of - 22 dB are also realised for the proposed filtering antenna.

Atmospheric environment monitoring system based on big data

Abstract: The invention discloses an atmospheric environment monitoring system based on big data. The atmospheric environment monitoring system includes a frequency collection circuit, detection calibration circuits and a filter transmitting circuit; a signal frequency of a simulated signal transmission channel input end is collected by the frequency collection circuit; a disturbing signal filter circuit composed of an operational amplifier AR2, an operational amplifier AR3 and a capacitor C4 is used by a first circuit of the detection calibration circuits to filter out disturbing signals; a triode Q5 is used by a second circuit of the detection calibration circuits to detect abnormal high level signals, and at the same time, an amplitude limiting circuit composed of a diode D3 and a diode D4 is used to limit signals; and finally, a signal conduction loss is decreased by the two circuit signals through a push-pull circuit composed of a triode Q3 and a triode Q4. According to the atmospheric environment monitoring system based on the big data, a filter circuit composed of an inductance L3, a capacitor C10 and a capacitor C11 is used by the filter transmitting circuit to filter out signals, sothe accuracy of corrected signals is ensured, the reliability of terminal error correction controlled by the atmospheric environment monitoring system is improved.

SAW Filters for Mobile Communications: Achievements and Prospects

Abstract: Modern achievements and directions of improvement of surface acoustic wave (SAW) filters for mobile communication systems are presented. SAW technology is continues to dominate in a tasks of filtration in radio frequency (RF) part of telecommunication systems. Innovative technologies of filters production and packaging allow to improve their characteristics and can reduce the size. I.H.P. SAW filter have a high Q-factor and good temperature and frequency characteristics. The main requirements to modern SAW filters are minimal losses, temperature stability, low level of nonlinear signals, high power durability, small dimensions. CSSP (Chip Sized SAW Package) technology and DSSP (die-sized SAW packaging) technology allow to produce miniature components and can integrate them into modules. The current trend of increasing the number of frequency bands and the introduction of new standards makes the problem of creating a flexible RF module with high-quality tunable SAW filters extremely actual.

New Operational Amplifier based Inverse Filters

Abstract: New first- order and second-order voltage-mode inverse filter circuits employing operational amplifier (opamp) are presented. The first-order inverse low-pass, first-order inverse high-pass and second-order inverse band-pass filter circuits are presented. The op-amp based first-order amplitude equalizer circuit is also presented. The considered inverse filters are checked for functionality using TINA SPICE simulator.