Electronic filter

About: Electronic filter is a research topic. Over the lifetime, 13207 publications have been published within this topic receiving 93063 citations. The topic is also known as: filter.

A 6.6-kV transformerless shunt hybrid active filter for installation on a power distribution system

Abstract: This paper presents a fully-digital-controlled shunt hybrid filter for damping of harmonic propagation in power distribution systems. The harmonic propagation is caused by resonance between line inductances and power capacitors installed for power factor correction. A possible solution to damping out harmonic propagation is based on installation of a shunt pure active filter at the end of a feeder This paper proposes a shunt hybrid active filter characterized by series connection of a 7th tuned LC filter per phase and a small-rated three-phase active filter. Like the pure filter, the hybrid filter is connected to the end bus of a feeder. The capacitor of the LC filter imposes a high impedance to the fundamental frequency, so that the fundamental voltage appears across the capacitor. This unique feature allows us to directly connect the hybrid filter to the 6.6 kV power line without step-down transformers. Furthermore, the capacitor used in this hybrid filter is lighter, cheaper and smaller than the transformer used in the pure filter. Theoretical analysis, along with experimental results obtained from a 200-V, 20-kW laboratory system, verifies the viability and effectiveness of the proposed hybrid filter.

Design analysis of low-pass passive filter in single-phase grid-connected transformerless inverter

Abstract: Presented is the design analysis of a single-phase grid-connected photovoltaic-inverter low-pass-output filter. It minimizes switching-frequency current harmonics, improving output response. The inverter is H-Bridge transformerless. Switching frequencies 8Hz, 14kHz, and 20kHz were compared for validation of the simulation and the experiment.

Multiple-loop absolute type rotary encoder based on rotating transformer

Abstract: The invention relates to a multiturn absolute rotary encoder based on a rotary transformer, which is characterized in that: a sensor is displaced by taking the rotary transformer as a shaft angle; a shaft angle decoding circuit can be formed by adopting DSP as a core processor; a sine wave which can be controlled by frequency and phase in the method that the circuit is synthesized by direct digital frequency for the numerical control of an oscillator; and the sine wave is directly taken as an excitation rotary transformer signal via a power amplifier and a filter circuit; the rotary transformer signal is transferred to A/D converter after being run through a matching circuit of electronic transformer; after sampling, digital filtering and digital signal processing, the sine and cosine value for the actual angle of two channels is generated; the angle error change is tracked dynamically by the PI algorithm; the mechanical displacement of the rotating object is converted into digital shaft angle position and speed. The multiturn absolute rotary encoder based on a rotary transformer has the advantages of high tracking speed, high conversion accuracy, high reliability, simple structure, sensitive movement, low environmental condition, strong anti-interference capability, high measuring accuracy and speed voltage output.

Miniaturized Transmission Lines Based on Hybrid Lattice-Ladder Topology

Abstract: This paper introduces hybrid structures with unit cells that are a combination of lattice and ladder topologies. These unit cells dramatically increase the quality factor, miniaturization, and maximum frequency of synthetic transmission lines. Also, it is shown that lattice topologies in general are less vulnerable to the effect of parasitics, such as self resonance of loading capacitors or mutual inductance between different cells. The underlying theory is studied, and simple formulas are given for predicting the behavior of these lines. A few examples are presented that, based on full-wave simulations, show the large gain in miniaturization, quality factor, or bandwidth compared to the simple ladder or lattice structures. Measured results for a fabricated synthetic line are presented that show a miniaturization factor of n=?{?eff?eff}=16.5 for Z 0=50 ? and a very small dispersive behavior from dc to 2.5 GHz.

Improved passive filter configurations for high-frequency conducted EMI in power electronics

Abstract: EMI filter design is critical for power electronics equipment to be in compliance with the EMI/EMC standards A good filter design realizes effective high frequency attenuation Such a design is often achieved empirically, with good common sense, and deemed, by and large, as an art rather than a science It is well known that the filter parasitics are detrimental to its ability to attenuate high frequency noise In this paper, the critical effects of parasitics, including component self-parasitics and their respective mutual coupling effects, are first identified and their impact to both differential and common mode noise are quantified Filter design techniques are proposed to mitigate these adverse effects due to self and mutual parasitics While reduction of certain critical parasitics such as, ESE of filter capacitors and certain mutual couplings can be realized relatively easily in the conventional discrete filter design practice, reduction of the winding capacitance of the common-mode/differential mode inductor can best be implemented in an integrated filter design Methods of reducing structural parasitics are investigated in this integrated filter design approach and a design technique proposed for canceling the winding capacitance of inductors that results in significant improvement of CM noise attenuation A unique class of integrated distributed interconnect EMI filter is introduced Experimental results are provided to substantiate all the claims made in the paper