نتایج جستجو برای: voltage and frequency vf control
تعداد نتایج: 17066384 فیلتر نتایج به سال:
building on previous studies on the effectiveness of different types of written corrective feedback, the present study aimed at investigating whether direct focused corrective feedback and direct unfocused corrective feedback produced any differential effects on the accurate use of english articles by efl learners across two different proficiency levels (low and high). in current study, the par...
abstract the purpose of this study is twofold: on the one hand, it is intended to see what kind of noticing-the –gap activity (teacher generated vs. learner generated) is more efficient in teaching l2 grammar in classroom language learning. on the other hand, it is an attempt to determine which approach of the noticing-the-gap- activity is more effective in the long- term retention of grammar...
One of the major challenges in standalone micro-grids (MG), is the frequency control. In this paper, a method for frequency control in a hybrid system based on wind turbine / photovoltaic / fuel cell and super capacitor is proposed. The proposed method is a combination of load frequency control and super capacitor voltage control. To determine the references power, PI controller and modified dr...
this study investigated the effects of three kinds of gloss conditions, that is traditional non-call marginal gloss, audio gloss, and extended audio gloss, on reading comprehension and vocabulary gain of iranian upper- intermediate efl learners. to this end, three experimental and one control groups, each comprising 15 participants, took part in the current study. in order to ensure that the pa...
power system blackouts have become a serious problem for electric utilities especially in recent years. different forms of system instability have emerged in recent blackouts, such as voltage instability and frequency instability. to counteract each form of system instability, special algorithms have been designed in the protection system, e.g. under frequency load shedding (ufls) and under vol...
In this paper, the circuit for a new bipolar differential voltage-to-frequency converter is presented. The circuit operation and the calculation of the operating frequency are described. The circuit design is also realized using Zetex transistor array integrated circuits and a 3.3-V power supply. This circuit incorporates an adjustable operating frequency via an external capacitor. The operatin...
BACKGROUND Extracorporeal cardiopulmonary resuscitation (ECPR) refers to the application of extracorporeal blood circulation with oxygenation as a resuscitation tool. The objective of this study is to observe the frequency component changes in the electrocardiogram (ECG) by ECPR during prolonged ventricular fibrillation (VF). METHODS Six swine were prepared as a VF model. Extracorporeal blood...
the purpose of this study was to investigate the relationship between family functioning and marital adjustment humor couples are due to the nature and objectives of the research and application of methods for its implementation correlation was used. the study population consisted of all the couples in the city who uses random cluster sampling of 200 students were selected as sample. data from ...
learning-oriented assessment seeks to emphasise that a fundamental purpose of assessment should be to promote learning. it mirrors formative assessment and assessment for learning processes. it can be defined as actions undertaken by teachers and / or students, which provide feedback for the improvement of teaching and learning. it also contrasts with equally important measurement-focused appro...
Transformerless topologies are widely preferred to use in the grid connected photovoltaic (PV) generation system due to higher efficiency, lower cost and lower weight in comparison with other topologies employing transformer. In this paper, switching losses is minimized by incorporating Zero Voltage Switching (ZVS) in a full-bridge topology, at switch turn-on and an adaptive Variable dead-time ...
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