In electric arc furnace steelmaking units, the essential parameters are reducing price, increasing production and decreasing environmental pollution. Electric arc furnaces are the largest users of electric energy in industry. The most important techniques that can be used to reduce the electric energy consumption in electric arc furnaces are scrap preheating, stirring, use of burners and hot ch...

There are various reasons why power factor correction circuit is used in various power supplies in large systems. The PFC (Power Factor Correction) at input stage becomes real necessary when the input power goes above 1kW typically. Recent advances in PFC include interleaving of two out-of-phase circuits to gain many system level advantages. Enough has been discussed about the advantages of int...

Medium and high power switch mode power supplies SMPS (>500W) used in telecommunications stations are normally based on the full-bridge DC-DC converter with isolation transformer. According to the transistors states, the full-bridge converter allows four different switching sates which can be used to control the output voltage of the SMPS, and to perform the power factor corrector (PFC) functio...

Reactive energy and power factor L2 1.1 The nature of reactive energy L2 1.2 Equipment and appliances requiring reactive energy L2 1.3 The power factor L3 1.4 Practical values of power factor L4 Why to improve the power factor? L5 2.1 Reduction in the cost of electricity L5 2.2 Technical/economic optimization L5 How to improve the power factor? L7 3.1 Theoretical principles L7 3.2 By using what...

This thesis focuses on the study, implementation and improvement of a digital controller for a power factor correction (PFC) converter. The development of the telecommunications industry and the Internet demands reliable, cost-effective and intelligent power. Nowadays, the telecommunication power systems have output current of up to several kiloamperes, consisting of tens of modules. The high-e...

New recommendations and future standards have increased the interest in power factor correction circuits. There are multiple solutions in which line current is sinusoidal. In addition, in the recent years, a great number of circuits have been proposed with nonsinusoidal line current. In this paper, a review of the most interesting solutions for single phase and low power applications is carried...

Conventional AC/DC power converters that are connected to the line through full-wave rectifier draws a non-sinusoidal input current. These Harmonic currents flowing through the impedances in the electrical utility distribution system can cause several problems such as voltage distortion, heating, noises. These harmonics distort the local voltage waveform, potentially interfering with other elec...

Harmonic pollution and low power factor in power systems caused by power converters have been a great concern. To overcome these problems several converter topologies and control schemes have been proposed in recent years. This paper is proposed to study the control techniques for such converters to improve the Power Factor (PF) and reduce total harmonic distortion (THD) in the input current wi...

Synchronous electric clocks utilize power grid frequency as their timing reference. Power grid frequency deviation away from its nominal value results in synchronous electric clocks running fast or running slow (also known as the time error). In this article, statistical analysis on time error of synchronous electric clocks around the world is firstly presented using the power grid frequency me...