This paper investigates a control approach for achieving reliable zero-voltage switching transitions within the entire operating range of a conventional no isolated bidirectional dc-dc converter that utilizes synchronous rectification. The approach is based on operation in the discontinuous conduction mode with a constant reversed current of sufficient amplitude, which is achieved by load-dependent variation of the switching frequency. This paper focuses on the obtained resonant voltage transitions and provides analytical models for determining the reversed current and timing parameters that would ensure safe, reliable, and highly efficient operation of the converter. In addition, the proposed approach solves the synchronous transistor's spurious turn-on and body diode reverse recovery induced issues, does not require any additional components or circuitry for its realization, and can be entirely implemented within a digital signal controller. The effectiveness and performance of the presented control approach was confirmed in a 1-kW experimental bidirectional dc-dc converter that achieved 97% efficiency over a wide range of output powers at switching frequencies above 100 kHz.
COBISS.SI-ID: 18799382
A new method for the automated measurement of the hysteresis of the temperature-compensated inductance-to-frequency converter with a single quartz crystal is proposed. The new idea behind this method is a converter with two programmable analog switches enabling the automated measurement of the converter hysteresis, as well as the temperature compensation of the quartz crystal and any other circuit element. Also used is the programmable timing control device that allows the selection of different oscillating frequencies. In the proposed programmable method two different inductances connected in series to the quartz crystal are switched in a short time sequence, compensating the crystal’s natural temperature characteristics (in the temperature range between 0 and 50 °C). The procedure allows for the measurement of the converter hysteresis at various values of capacitance connected in parallel with the quartz crystal for the converter sensitivity setting at selected inductance. It, furthermore, enables the measurement of hysteresis at various values of inductance at selected parallel capacitance (sensitivity) connected to the quartz crystal. The article shows that the proposed hysteresis measurement of the converter, which converts the inductance in the range between 95 and 100 μH to a frequency in the range between 1 and 200 kHz, has only 7×10−13 frequency instability (during the temperature change between 0 and 50 °C) with a maximum 1×10−11 hysteresis frequency difference.
COBISS.SI-ID: 19646998
This study aims to create a bibliometric profile of the Journal Computers in Human Behavior employing bibliometric analysis, bibliometric mapping and thematic analysis to identify its document types, the dynamics and trends of research literature production, impact factor, most cited articles, and large contributing institutions and countries. Additionally, the authors were interested in finding the established patterns of cooperation among countries and institutions and the most productive research themes and their evolution through time.We were also interested in finding out if there are any sleeping beauties among articles published in the Journal. The study revealed a positive trend of scientific literature production and that the average number of references is increasing contrary to the number of pages per publication, which is decreasing, although it has remained stable in recent years. The most productive countries and institutions are from the United States, and the majority of the literature production is done by economically and scientifically fit and well developed countries. The identified research themes correspond with the Journal's aims and scope. The rising number of publications, increasing number of citations and, consequently, the Journal impact factor, together with the existence of sleeping beauties, shows that the editorial policy is well thought out and future oriented.
COBISS.SI-ID: 88408065
The paper describes the impact of non-condensable gas (NCG) on heat transfer in a steam turbine condenser (STC) and modelling of the steam ejector pump system (SEPS) by controlling the gas extraction rate through extraction tubes. The ideal connection points for the NCG extraction from the STC are identified by analysing the impact of the NCG on the heat transfer and measuring the existing system at a thermal power plant in Slovenia. A simulation model is designed using the Matlab software and Simulink, Neural Net Work, Fuzzy Logic and Curve Fitting Toolboxes, to control gas extraction rate through extraction tubes of the gas pumped from the STC, thus optimising the operation of the steam ejector pump system (SEPS). The gas extraction rate from the STC is controlled in the extraction tubes by pumping only the NCG to the maximum extent. The SEPS is optimised by selecting a Laval nozzle of appropriate size to reduce the steam for the operation of the SEPS, whereby the amount of the extracted NCG is maintained. As the SEPS motive steam is produced in a boiler, the consumption of coal for the production of the SEPS motive steam is reduced as well as the greenhouse gas environmental pollution.
COBISS.SI-ID: 19707158
Divers commonly use buoyancy vests for maintenance and changing depth. They do this by manually actuating two pneumatic valves that cause the jacket's volume to expand or shrink, thus changing its buoyancy. Divers desire for a device that would automatically modify or maintain depth has been present since the beginning of modern diving using a buoyancy vest. The need arises mainly when diving: where poor visibility is present; when both hands are needed for the job; during amateur dives; where decompression procedures are needed; to limit the maximum ascending speed; during a safety stop procedure; automatic ascending when a diver's life functions are critical but nevertheless using the same technology for changing depth in small modern submarines and submarine-like vessels. A prerequisite for successful buoyancy control is definitely knowledge of the system's behaviour based on mathematical modelling. This paper proposes a detailed dynamic model of a diver with all its accessories. The accuracy of the model was validated by comparing simulation results with the measurement results of various experiments.
COBISS.SI-ID: 19478550