Question

一篇关于电力电子方面的纯英文论文，要有论文相应格式，最少1500字。急~

Answer 1

Abstract: With the development of power electronics technology, harmonic hazards
has become increasingly serious, harmonic governance issues has been imminent.
On the power source for electronic devices harmonic analysis and concluded that
its harm and the corresponding harmonic management principles and comprehensive
management, and management of a harmonic outlook.

Key words: power
electronics; harmonics; hazards; inhibition

INTRODUCTION

With the
development of power electronics technology, power electronic devices to the
extensive application of power system harmonics caused serious pollution.
Various power electronic equipment in the transport, metallurgical, chemical and
other industrial traffic the extensive application of harmonics in the grid
problem is becoming increasingly serious, many low power factor of power
electronic devices to the power grid additional burden on the quality of power
and influence, Therefore, the power electronic devices harmonic pollution has
become hinder the development of power electronics technology major obstacles.
Therefore, inhibition harmonic pollution and improve the power factor of power
electronics technology has become a major issue in the. This paper focus on the
key issues of power through electronic harmonic sources and the danger of
understanding and analysis, and control of pollution from the relationship
between the consideration of a comprehensive management approach on the final
harmonic trends in the development of comprehensive management of the
prospect.

A power electronic device - the main source of
harmonics

Nonlinear load is a harmonic sources, which caused grid voltage
distortion, in the voltage several times with the whole of the fundamental
frequency component. Harmonic as the main source of power for various electronic
devices mainly AC-DC converter (rectifiers, inverters, chopper, Drives), as well
as bidirectional thyristor controlled switching equipment, as well as internal
power system Variable Flow equipment, such as HVDC rectifier valve and the
valve, and other inverter. Below its harmonics generated an analysis of the
situation.

1.1 Rectifier

As a DC power supply devices, rectifiers
widely used in various occasions. Figure 1 (a) and Figure 1 (b) respectively for
the single-phase and three-phase circuits typical. In rectifier devices, AC
power supply for the current rectangular wave, rectangular wave of the
fundamental frequency for the current and Jibeiai several times for the
high-frequency harmonic current waveform synthesis. Obtained by Fourier series
of rectangular wave of high harmonics In fundamental component I1 and the
largest ratio of 1 / n, with the trigger control angle α, and the decrease of
overlap angle μ for the increase of harmonic wave components have reduced
trend.

In addition, the existing research results indicate that:
Rectifier harmonic current operation mode of the size, has a direct impact,
therefore consider adjusting the voltage and current rectifier, it is best to
conduct overlap angle, as well as for harmonic phase pressure drop calculations,
in order to determine safe and economical operation mode when the control close
to 40 ° angle α, overlapping in the 8 ° angle μ about the circumstances are
often the most serious state of harmonic, so to go through, as far as possible
through the correct choice of regulating transformers tap in order to avoid
Harmonic most serious point [1].

1.2 exchange regulator

Exchange
regulator used for lighting dimming and induction motor speed, and so on. Figure
2 (a) and 2 (b) respectively for the single-phase and three-phase circuits
typical. Exchange regulator and the harmonic frequency rectifier basically the
same.

Frequency Converter 1.3

Frequency converter is AC / AC
Converter behalf of equipment, when used as mot