Control Strategy of 1 kV Hybrid Active Power Filter for Mining Applications

The paper presents a shunt hybrid active power filter for 1 kV mining applications in configuration with a single-tuned passive filter. The focus is on the method of controlling the filter, with particular emphasis on the influence of network voltage distortion and time delays in control on the effectiveness of harmonic reduction, which is one of the most important aspect of power quality. The low-power loss configuration of a hybrid filter with SiC transistors is shown, as well as the control algorithm which limits the influence of voltage distortion. Theoretical considerations are verified by results obtained from simulations and tests of the hybrid active power filter prototype.

Optimization of digital filters performances simultaneously in frequency and time domains

Wide used method of digital filters design consists in transformation of analog filter-prototype with required performances into digital filter. This method is applicable if the transformation preserves optimality of filter performances under specified set of quality indexes (QI). It was denoted earlier that such situation is possible when gain-frequency response (GFR) and phase-frequency response are optimized simultaneously. The task of simultaneous optimization of digital filters GFR and step response (SR) is also important but yet a little explored. Alternative method of this problem solving consists in search of digital filter transfer function (TF) which is optimal under GFR and SR QI’s. To investigate capabilities of the first method we found examples of analog filters Pareto-optimal under rise time and transient duration. Other QI’s of these filters fulfilled specified constraints. Then these filters were transformed into digital filters. Bilinear transformation and transformation with invariant impulse response were applied. Further we did the search of digital filters optimal under the same set of QI’s. In either method the hybrid heuristic algorithm was applied for search optimal solutions in the space of TF poles and zeroes coordinates. The results of investigation demonstrated that digital filters developed via search are superiorly under specified set of QI’s then digital filters developed via transformation of analog filters. Accordingly Pareto-optimality for QI of GFR and SR is not preserved during such transformation and direct search must be applied to optimized digital filters simultaneously in frequency and time domains. Further in some cases analog filters developed via reverse bilinear transformation of the found optimal digital filters are superiorly under the same set of QI’s then analog filters developed using search. In such cases using of digital filter-prototypes for design of analog filters is practical.

A dual resonance high frequency bandpass filter

This paper presents a design of dual resonance high frequency bandpass filter using Sonnet EM Simulator. Filter prototype is enhanced by adding the short stub in the center of the design. A parametric study shows the impact of choosing appropriate configuration characteristics. This is a dual resonance bandpass filter design, with center frequencies and . Performed input match at first resonance is and insertion loss is . The obtained results at second resonance are and . Due to its characteristics, this is a high-Q medium bandwidth dual resonance bandpass filter. The design is simulated and planning to be fabricated with 0.36 mm thickness and dielectric constant . This paper benefits from its compact size and simple geometry over the similar filters found in literature.

Высокоселективный полосковый фильтр нижних частот с уровнем заграждения более 100 dB в широкой полосе

A new miniature strucuter of a highly selective low-pass filter (LPF) on a suspended substrate with a double-sided topology of stripline conductors has been proposed. The steepness of the slope of the frequency response of the filter and the depth of the stopband are determined by the zeros of the transmission coefficient, which number is equal to the order of the filter. The synthesis of a fifth-order low-pass filter prototype on a 0.5-mm thick alumina substrate with a relative permittivity εr = 9.8 was performed by numerical electrodynamic analysis of its 3D model. The filter passband cut-off frequency at the level of –1 dB fc = 1.75 GHz, and the length of the stopband at the −100 dB level extends to a frequency of 4.4 fc.

Novel Dual band SIW Filter Using Quad mode Cavity

A dual-band bandpass substrate integrated waveguide (SIW) filter is proposed using a quad-mode cavity in this paper. First two degenerative modes (TE102 and TE201) with via perturbation give the first passband. The second passband is realised by using higher modes (side and diagonal modes of TE202) which are obtained by putting square slot at the center of the cavity. The square slot increases the frequency ratio of the center frequencies of first and second passbands. Moreover, orthogonal feed-lines are used in the proposed design to increase transmission zeros (TZs) which helps to improve the selectivity and out-of-band rejection of the filter. Designed and fabricated a dualband filter prototype using a single layer printed circuit board (PCB) technology, size is only 19 mm × 19 mm. The insertion losses are 2.1 dB and 2.4 dB, and fractional bandwidths of 3.40 per cent and 2.00 per cent at 11.00 and 15.58 GHz, respectively. The measurement results show close agreement with the simulation results.