Research of hybrid active power filter based on FBD method detection
To fast and effectively detect harmonic current of power system, FBD method is proposed. Compared with method which is based on instantaneous reactive power, FBD method has no complex transformation and transformation, it can be used to detect harmonic current for single-phase, three-phase three-wire and three-phase four-wire system. But FBD method needs a low-pass filter to extract the DC current, it causes delay and phase-shifting problems, to solve these problems, this paper presents a real-time sliding window to extract the DC current instead of low-pass filter. At the same time, shows the principle of hybrid active power filter, and corresponding mathematical model is established. Finally, take a new composite control strategy. Simulation results show correctness of the detection and effectiveness of the new composite control strategy.
DEFINITION AND COMPENSATION OF GENERALIZED INSTANTANEOUS REACTIVE CURRENT AND REACTIVE POWER IN abc COORDINATES
A new definition method for generalized instantaneous reactive current and reactive power of three-circuits in abc coordinates is presented and the detection and compensation method for generalized instantaneous reactive current is proposed. The results of simulation and research demonstrate that any additional hardware is not needed for the detection of the generalized instantaneous reactive current. For abrupt change of current the accurate detection of generalized instantaneous reactive current can be implemented in one power frequency period by the proposed method, meanwhile, the transmission loss is minimal and the distortion factor of the voltage is reduced to the minimum.
Semiautomated quantification of the fibrous tissue response to complex three-dimensional filamentous scaffolds using digital image analysis.
Fibrosis represents a relevant response to the implantation of biomaterials, which occurs not only at the tissue-material interface (fibrotic encapsulation) but also within the void fraction of complex three-dimensional (3D) biomaterial constructions (fibrotic ingrowth). Usual evaluation of the biocompatibility mostly depicts fibrosis at the interface of the biomaterial using semiquantitative scores. Here, the relations between encapsulation and infiltrating fibrotic growth are poorly represented. Virtual pathology and digital image analysis provide new strategies to assess fibrosis in a more differentiated way. In this study, we adopted a method previously used to quantify fibrosis in visceral organs to the quantification of fibrosis to 3D biomaterials. In a proof-of-concept study, we transferred the "Collagen Proportionate Area" (CPA) analysis from hepatology to the field of biomaterials. As one task of an experimental animal study, we used CPA analysis to quantify the fibrotic ingrowth into a filamentous scaffold after subcutaneous implantation. We were able to demonstrate that the application of the CPA analysis is well suited as an additional fibrosis evaluation strategy for new biomaterial constructions. The CPA method can contribute to a better understanding of the fibrotic interactions between 3D scaffolds and the host tissue responses.