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There has been widespread research in the area of sensorless rotor-position measurement in switched reluctance (SR) motor drives. However, there is still a lack of detailed stability and accuracy analysis for the sensorless SR drive system. In this paper, a sensorless rotor-position-measurement method for an SR motor drive is presented. The method is based on estimating a particular rotor position on a phase-by-phase basis and measuring the flux linkage and current when the estimated position is reached. By comparing the measured flux linkage with the pre-stored flux linkage corresponding to the particular position for the measured current, the angular difference between the estimated and particular positions can be calculated. The method is applied to two practical systems, the first being a 0.3-kW 10 000-r/min three-phase 614 SR motor with a variable load, and the second being a 1-kW 1500-r/min three-phase 12/8 SR motor with a fan load. This paper examines the theoretical stability of the measurement and shows that measurement errors are not compounded and act as a variable disturbance to the system. The theoretical accuracy of the measurement is examined and shown to be acceptable. Index Terms--Sensorless position measurement, stability and accuracy, switched reluctance (SR) drive.

Shaft position transducers are commonly used to provide rotor position information for commutation of the switched reluctance (SR) motor and for excitation control. However, in low cost applications such as fans and pumps, particularly at low power levels, the shaft position sensor is too costly. Therefore, a simple sensorless position drive system is preferred. It is the aim of this article to present a simple sensorless rotor position measurement for a SR using the magnetization data of the motor windings. The proposed method is based on estimating a particular rotor position on a phase by phase basis and measuring flux linkage and current when the estimated position is reached. By comparing the measured flux linkage with the prestored flux linkage corresponding to the particular position for the measured current, the angular difference between the estimated position and the particular position can be calculated. The proposed sensorless SR drive system has been tested in the laboratory and its output performance was compared to the output of commercial system based on an optical sensor. © 2000 American Institute of Physics. [S0021-8979(00)16708-8] [ABSTRACT FROM AUTHOR]

Smart capsules are developing at a tremendous pace with a promise to become effective clinical tools for the diagnosis and monitoring of gut health. This field emerged in the early 2000s with a successful translation of an endoscopic capsule from laboratory prototype to a commercially viable clinical device. Recently, this field has accelerated and expanded into various domains beyond imaging, including the measurement of gut physiological parameters such as temperature, pH, pressure and gas sensing, and the development of sampling devices for better insight into gut health. In this review, the status of smart capsules for sensing gut parameters is presented to provide a broad picture of these state-of-the-art devices while focusing on the technical and clinical challenges the devices need to overcome to realise their value in clinical settings. Smart capsules are developed to perform sensing operations throughout the length of the gut to better understand the body's response under various conditions. Furthermore, the prospects of such sensing devices are discussed that might help readers, especially health practitioners, to adapt to this inevitable transformation in healthcare. As a compliment to gut sensing smart capsules, significant amount of effort has been put into the development of robotic capsules to collect tissue biopsy and gut microbiota samples to perform in-depth analysis after capsule retrieval which will be a game changer for gut health diagnosis, and this advancement is also covered in this review. The expansion of smart capsules to robotic capsules for gut microbiota collection has opened new avenues for research with a great promise to revolutionise human health diagnosis, monitoring and intervention., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)