Czeslaw T. Kowalski and Jacek D. Lis
The purpose of this paper is to present a fixed‐point implementation of a complete direct torque control (DTC) algorithm connected with a rotor speed estimation algorithm for the…
Abstract
Purpose
The purpose of this paper is to present a fixed‐point implementation of a complete direct torque control (DTC) algorithm connected with a rotor speed estimation algorithm for the induction motor drive, using field‐programmable gate array (FPGA).
Design/methodology/approach
The parallel processing approach is described, which requires a decomposition of the control and estimation algorithms for the converter‐fed induction motor to several tasks, realised in parallel. The advanced data processing techniques are described, like PIPELINE technique for data streams design, coordinate rotation digital computer algorithm for transformation of stator flux vector components from Cartesian to polar coordinates. Moreover, the method for the qualitative analysis of the full‐order state observer's sensitivity to the variations of the induction motor equivalent circuit parameters is presented.
Findings
It is shown that the developed FPGA‐based DTC structure enables designing an efficient application for the induction motor control. Owing to the high‐processing frequency, the digital FPGA‐based DTC application is similar in its features to the analogue realisation based on the comparators. Yet all the advantages of the digital structure, i.e. high flexibility, parameterization capability, etc. remain unchanged. Furthermore, FPGA is hardware realisation of a digital data processing algorithm; hence the reliability of the control system is improved.
Research limitations/implications
The investigations are performed in the developing prototype setup, based on PXI‐1042 Industrial PC equipped with Xilinx Virtex‐II FPGA matrix, programmed with LabVIEW.
Practical implications
The experimental tests of the FPGA‐based implementation of the whole control structure of the sensorless DTC drive system are demonstrated. It is also shown, that the full‐order state observer with the speed adaptation loop is significantly sensitive to motor parameter variations in the low‐speed region, which must be taken into account while designing the adaptation algorithm for speed estimation in real application.
Originality/value
The paper's value lies in the overall, FPGA‐based design of the speed sensorless DTC structure for the induction motor including motor speed, torque and stator flux control loops, stator flux and rotor speed estimation.
Details
Keywords
Anna Matysek and Jacek Tomaszczyk
The quest to discover optimal conditions or amounts has been carried out in many scientific disciplines and practical fields. In astrophysics, biology, medicine, psychology and…
Abstract
Purpose
The quest to discover optimal conditions or amounts has been carried out in many scientific disciplines and practical fields. In astrophysics, biology, medicine, psychology and education, the quest has resulted in finding the right amount of something, a desirable middle between extremes, a balance between conditions or the optimal state of a system. The results are referred to as the Goldilocks principle, which is based on the idea of being “just right”. The aim of our study was to find out if there are any measures in information search that could be identified as Goldilocks ranges.
Design/methodology/approach
We conducted a user experiment in which 68 participants carried out a time-unlimited, topical search task involving finding relevant websites on the basis of which the participants were supposed to prepare a presentation on a given topic. We examined aspects of their search behavior.
Findings
We found that information search Goldilocks ranges can be identified for a length of a search session, number of relevant results, number of queries submitted and number of search engine results pages (SERPs) visited. This preliminary study has resulted in indicating the following dominant ranges: Number of relevant documents found: 5–8; Time spent searching: 21–35 min; Number of queries submitted: 3–7; Number of SERPs viewed: 1–3.
Originality/value
Till now, no one has studied Goldilocks ranges in information retrieval. The Goldilocks ranges have some practical implications for improving the effectiveness of web searching.
Details
Keywords
Mariusz Oszust, Tomasz Kapuscinski, Dawid Warchol, Marian Wysocki, Tomasz Rogalski, Jacek Pieniazek, Grzegorz Henryk Kopecki, Piotr Ciecinski and Pawel Rzucidlo
This paper aims to present a vision-based method for determination of the position of a fixed-wing aircraft that is approaching a runway.
Abstract
Purpose
This paper aims to present a vision-based method for determination of the position of a fixed-wing aircraft that is approaching a runway.
Design methodology/approach
The method determines the location of an aircraft based on positions of precision approach path indicator lights and approach light system with sequenced flashing lights in the image captured by an on-board camera.
Findings
As the relation of the lighting systems to the touchdown area on the considered runway is known in advance, the detected lights, seen as glowing lines or highlighted areas, in the image can be mapped onto the real-world coordinates and then used to estimate the position of the aircraft. Furthermore, the colours of lights are detected and can be used as auxiliary information.
Practical implications
The presented method can be considered as a potential source of flight data for autonomous approach and for augmentation of manual approach.
Originality/value
In this paper, a feasibility study of this concept is presented and primarily validated.