نتایج جستجو برای: مبدل سوییچینگ pwm

تعداد نتایج: 8153  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه بوعلی سینا - دانشکده مهندسی 1390

یک مبدل چندسطحی، ساخت ولتاژ خروجی دلخواه را با ترکیب چندین ولتاژ ورودی dc ممکن میسازد. از این رو، این دسته مبدلها در کاربردهای صنعتی ولتاژ بالا و جریان dc، محرکه های الکتریکی، ادوات facts و... کاربرد گستردهای دارند. مبدلهای چندسطحی نوعی از مبدلهای الکترونیک قدرت محسوب میشوند که در عین دارا بودن اعوجاج اندک ولتاژ، توانایی ساخت ولتاژ بالا را نیز دارند. این ویژگی مهم سبب شده تا مبدلهای چندسطحی در ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه فردوسی مشهد - دانشکده مهندسی 1393

با توجه به کاربردهای گوناگون و مزایای زیادی که مبدل¬های منبع ولتاژی pwm متصل به شبکه ارائه می¬دهند، روش-های کنترلی مختلفی برای بهره¬مندی از این کاربردها و مزایا ارائه شده¬اند که از بین آن ها، روش¬های کنترل بدون سنسور ولتاژ شبکه به دلیل مزایای ویژه آن¬ها، مورد توجه زیادی قرار گرفته¬اند. در این راستا در این پایان¬نامه دو روش جدید برای تخمین ولتاژ شبکه در حوزه¬ی زمان ارائه شده و عملکرد آن ها مورد ...

2010
S. Srinivas V. T. Somasekhar

An open-end winding induction motor, fed by two 2-level inverters connected at either end produces space vector locations, identical to those of a conventional 3-level inverter. In this paper, two switching algorithms are proposed to implement space vector PWM for the dual inverter scheme. The proposed algorithms do not employ any look-up tables. The time consuming task of sector identification...

2016
Matthias Hinkfoth Ralf Salomon

Pulse-width modulation (PWM) is known for simple digital-to-analog conversion and motor current control. But up to now, PWM is not known for high speed communication. This paper shows how to implement the physical layer of a fully digital PWM-based communication system. For performance reasons the PWM senders and receivers are implemented using asynchronous logic. The proposed calibration proce...

2005
J. Russi M. L. Martins H. A. Gründling H. Pinheiro J. R. Pinheiro H. L. Hey

This paper proposes an improved design to calculate the snubber auxiliary elements of ZVT DC-DC PWM converters with snubber assisted auxiliary switch. The proposed improved design guidelines are based on the reduction of the conduction losses through the auxiliary circuit. It is accomplished by the unique location of the turn-off snubber capacitor, which is shared by both active switches. By me...

2000
Leon M. Tolbert Thomas G. Habetler

 The advent of the transformerless multilevel inverter topology has brought forth various pulse width modulation (PWM) schemes as a means to control the switching of the active devices in each of the multiple voltage levels in the inverter. An analysis of how existing multilevel carrier-based PWM affects switch utilization for the different levels of a diode-clamped inverter is conducted. Two ...

2015
Sneha S. Ghorpade

The objective is to develop a fault diagnose scheme for MOSFET’s open switch faults for PWM voltage source inverter (PWM-VSI) motor drives. Here system monitors line to line voltage as well as switching signals nevertheless the triggering time of MOSFET, under both healthy and faulty conditions. So the measurement of line to line voltage is taken which gives the information about switching stat...

2014
S. Senguttuvan S. Senthilkumar

The aim of study of this paper is design and implementation of a simple and efficient soft switched Pulse Width Modulation (PWM) for three-phase induction motor drives. Soft-switching techniques have gained popularity in recent times because they offer many advantages over hard-switched Pulse Width Modulated inverters such as higher efficiency, higher power density and better performances. The ...

Journal: :The Journal of clinical investigation 1980
A Saxon C Morrow R H Stevens

The B lymphocyte subpopulations producing immunoglobulin (Ig)E and the regulatory T cells modulating this IgE production in normals, and in atopic patients with respiratory allergy, atopic dermatitis, and markedly elevated serum IgE levels (>5,000 ng/ml), were investigated. Peripheral blood lymphocytes (PBL) were separated into T and B cell fractions and the ability of B cells to produce IgE in...

2010
Kenji NISHIBORI Setsuya KONDO Kazuhiko OSHIMA

A traveling wave-type ultrasonic motor (USM) has a self-locking characteristic due to a static frictional force present when its power supply is turned off, because its rotor is pressed strongly to the stator in the USM. We propose a pulse width modulation (PWM) method in consideration of this self-locking characteristic in order to control the motion of USM. The vibration waveform and the driv...

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