scholarly journals Adaptive Power Line Harmonic Detection for Active Filter Applications

Author(s):  
Weidong Liu

The objective of this thesis research is to develop an efficient method for accurate detections of power line harmonic distortions for the control of active filters. The research has achieved its objective with four significant results. First, an adaptive power line harmonic detection method is developed, which is based on the findings of extensive research in the areas of inside and outside of power electronics controls. Second, a simple and practical formulation of the adaptive harmonic detection method is developed, which is simplified significantly from the original complex design formulations for noise cancellations. Third, vigorous verifications of effectiveness of the adaptive detection method using computer simulations are carried out, which cover the steady state operations, the dynamic operations, normal power line conditions, non-ideal supply and load conditions, etc. Fourth, experimental verifications of the accuracy of the adaptive detection method are conducted, which cover typical distorted power line conditions for normal and unbalanced operations. For illustration, this thesis presents carefully designed computer simulation and experimental case studies that cover a wide range of power line conditions.

2021 ◽  
Author(s):  
Weidong Liu

The objective of this thesis research is to develop an efficient method for accurate detections of power line harmonic distortions for the control of active filters. The research has achieved its objective with four significant results. First, an adaptive power line harmonic detection method is developed, which is based on the findings of extensive research in the areas of inside and outside of power electronics controls. Second, a simple and practical formulation of the adaptive harmonic detection method is developed, which is simplified significantly from the original complex design formulations for noise cancellations. Third, vigorous verifications of effectiveness of the adaptive detection method using computer simulations are carried out, which cover the steady state operations, the dynamic operations, normal power line conditions, non-ideal supply and load conditions, etc. Fourth, experimental verifications of the accuracy of the adaptive detection method are conducted, which cover typical distorted power line conditions for normal and unbalanced operations. For illustration, this thesis presents carefully designed computer simulation and experimental case studies that cover a wide range of power line conditions.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Erfan Rezvani Ghomi ◽  
Saeideh Kholghi Eshkalak ◽  
Sunpreet Singh ◽  
Amutha Chinnappan ◽  
Seeram Ramakrishna ◽  
...  

Purpose The potential implications of the three-dimensional printing (3DP) technology are growing enormously in the various health-care sectors, including surgical planning, manufacturing of patient-specific implants and developing anatomical models. Although a wide range of thermoplastic polymers are available as 3DP feedstock, yet obtaining biocompatible and structurally integrated biomedical devices is still challenging owing to various technical issues. Design/methodology/approach Polyether ether ketone (PEEK) is an organic and biocompatible compound material that is recently being used to fabricate complex design geometries and patient-specific implants through 3DP. However, the thermal and rheological features of PEEK make it difficult to process through the 3DP technologies, for instance, fused filament fabrication. The present review paper presents a state-of-the-art literature review of the 3DP of PEEK for potential biomedical applications. In particular, a special emphasis has been given on the existing technical hurdles and possible technological and processing solutions for improving the printability of PEEK. Findings The reviewed literature highlighted that there exist numerous scientific and technical means which can be adopted for improving the quality features of the 3D-printed PEEK-based biomedical structures. The discussed technological innovations will help the 3DP system to enhance the layer adhesion strength, structural stability, as well as enable the printing of high-performance thermoplastics. Originality/value The content of the present manuscript will motivate young scholars and senior scientists to work in exploring high-performance thermoplastics for 3DP applications.


1994 ◽  
Vol 30 (2) ◽  
pp. 165-174 ◽  
Author(s):  
Ralf Otterpohl ◽  
Thomas Rolfs ◽  
Jörg Londong

Computer simulation of activated sludge plant for nitrogen removal has become a reliable tool to predict the behaviour of the plant Models including biological phosphorus removal still require some practical experience but they should be available soon. This will offer an even wider range than today's work with nitrogen removal. One major benefit of computer simulation of wastewater treatment plants (WTP) is the optimization of operation. This can be done offline if hydrographs of a plant are collected and computer work is done with “historical” analysis. With online simulation the system is fed with hydrographs up to the actual time. Prognosis can be done from the moment of the computer work based on usual hydrographs. The work of the authors shows how accuratly a treatment plant can be described, when many parameters are measured and available as hydrographs. A very careful description of all details of the special plant is essential, requiring a flexible simulation tool. Based on the accurate simulation a wide range of operational decisions can be evaluated. It was possible to demonstrate that the overall efficiency in nitrogen removal and energy consumption of ml activated sludge plant can be improved.


Author(s):  
Martina Ladrova ◽  
Radek Martinek ◽  
Jan Nedoma ◽  
Marcel Fajkus

Electromyogram (EMG) recordings are often corrupted by the wide range of artifacts, which one of them is power line interference (PLI). The study focuses on some of the well-known signal processing approaches used to eliminate or attenuate PLI from EMG signal. The results are compared using signal-to-noise ratio (SNR), correlation coefficients and Bland-Altman analysis for each tested method: notch filter, adaptive noise canceller (ANC) and wavelet transform (WT). Thus, the power of the remaining noise and shape of the output signal are analysed. The results show that the ANC method gives the best output SNR and lowest shape distortion compared to the other methods.


1998 ◽  
Vol 4 (4) ◽  
pp. 311-335 ◽  
Author(s):  
Stefano Nolfi ◽  
Dario Floreano

Coevolution (i.e., the evolution of two or more competing populations with coupled fitness) has several features that may potentially enhance the power of adaptation of artificial evolution. In particular, as discussed by Dawkins and Krebs [3], competing populations may reciprocally drive one another to increasing levels of complexity by producing an evolutionary “arms race.” In this article we will investigate the role of coevolution in the context of evolutionary robotics. In particular, we will try to understand in what conditions coevolution can lead to “arms races.” Moreover, we will show that in some cases artificial coevolution has a higher adaptive power than simple evolution. Finally, by analyzing the dynamics of coevolved populations, we will show that in some circumstances well-adapted individuals would be better advised to adopt simple but easily modifiable strategies suited for the current competitor strategies rather than incorporate complex and general strategies that may be effective against a wide range of opposing counter-strategies.


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