نتایج جستجو برای: high frequency inverters

تعداد نتایج: 2391219  

2013
V. Arun B. Shanthi S. P. Natarajan

The need for high power apparatus in industry has increased in recent years. Multilevel inverters have developed as easy alternatives for such power requirements. Multilevel inverters consist of a group of semiconductor switches and a set of voltage source components like capacitors or independent sources. The basic concept of these inverters depends on using this series of switches and sources...

2012
Y-F. Wu J. Kang

Silicon-based power switching devices have improved dramatically since their inception decades ago. An impressive example: Si super-junction MOSFETs, such as CoolMOS FETs, broke the theoretical Si limit in the tradeoff between blocking voltage and resistance (Ref. 1). However, the large amount of minority charge in the body diode results in large reverse recovery losses in hardswitched bridge c...

2008
Eric Seymour

While high-power PV installations certainly vary in configuration, a typical commercially installed system (Figure 1) consists of the following: • PV modules stacked in strings not to exceed 600 V open-load, referenced to ground on either positive or negative leg • A UL1741-certified inverter whose function, in addition to converting direct current to alternating current, is to act as an autono...

This paper presents the comparative study of three phase twenty five level diode clamped and cascaded H-bridge multilevel inverters. The comparison is made in respect of requirement of devices, quality of output voltage and reduction of total harmonic distortion at the multilevel inverter terminals. In this work multicarrier sinusoidal pulse modulation control methods of Phase disposition (PD-P...

2014
Yu Zhang Minying Li Yong Kang Chris Bingham

In three-phase inverters used in uninterruptible power supplies (UPSs), three-limb inductors and three-limb transformers are commonly used in consideration of cost and size. However, magnetic coupling exists between the three phases of the inverter, which can result in complex models. When instantaneous feedback control strategies are introduced to achieve high quality output waveforms, the tra...

2004
A. Azli W. S. Ning

Absrracr-Various circuit topologies and control techniques have been proposed on inverters for AC power supply applications but without much emphasis on very high power systems. Incorporation of a non conventional inverter topology known as multilevel inverter with an optimal PWM based control scheme is proposed in this work for high voltage applications when the switching frequency of the inve...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه فردوسی مشهد - دانشکده ادبیات و علوم انسانی دکتر علی شریعتی 1393

the purpose of the present study was to investigate the relationship between fear of negative evaluation (fne) and communication strategies (css) among iranian efl learners. it was aimed to examine the differences in the use of communication strategies between speakers with high or low degree of fear of negative evaluation. the current study was a case study consisting of 10 english learners at...

2011
D. Sandhya Rani

Multilevel inverters are increasingly being used in high-power medium voltage applications due to their superior performance compared to two-level inverters. Among various modulation techniques for a multilevel inverter, the space vector pulse width modulation (SVPWM) is widely used. The complexity is due to the difficulty in determining the location of the reference vector, the calculation of ...

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