Application of the hottest power factor correction

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The application of power factor correction technology in electronic ballast introduction electronic ballast is a new type of ballast which replaces the traditional inductive ballast and is used with fluorescent lamp. It is the key product to realize green lighting. Lighting power accounts for about 20% of the total power generation of mankind. The popularization and use of electronic ballast will save more than 20% of lighting power. In addition, it can make the light emitted by fluorescent lamps soft and without stroboscopic, which is conducive to the protection of human eyes. Therefore, The research and production of high-performance electronic ballasts have received extensive attention at home and abroad

as far as high-performance electronic ballast is concerned, one of the most key technical indicators at present is the total harmonic content of its power supply incoming line current and the power factor of the line. If the harmonic content of the incoming current of the electronic ballast power supply is large, it will bring pollution to the electricity. As for the line power factor of the electronic ballast, it will also directly affect the utilization efficiency of electricity. In order to reduce the pollution to AC, some standards for limiting current harmonics have been introduced at home and abroad. For example, according to the development of electronic ballasts in the world, the International Electrotechnical Commission (IEC) set up a special technical team a few years ago to study relevant technical issues and standards, The corresponding IEC standard IEC1000-3-2 class c[1] has been issued

the traditional rectifier bridge plus capacitor structure only has the input current when the peak value of the input AC voltage is close to the investment range, resulting in a large harmonic component in the input current, which is far from meeting the standard requirements. In order to make the input current harmonic meet the standard requirements, it is necessary to consider how to carry out power factor correction without increasing too much cost. In recent years, China has started the research work in this area, but due to the late start, the current research has not reached the level of popularization and application. Therefore, this paper first introduces the basic principle of power factor correction, and then comprehensively introduces the application of single-stage power factor correction technology in electronic ballast

2 basic principle of power factor correction in june2015

power factor (PF) is defined as the ratio of AC input real power to input apparent power, i.e.

where: p=vi1cos α 。



γ Represents the relative value of fundamental current, which is called waveform distortion factor, cos α It is called the displacement factor. That is, the power factor is the product of distortion factor and displacement factor. To achieve a power factor of 1, the input current of the system must be in phase with the input voltage, and the input current must have no harmonic component

the methods of power factor correction include passive correction technology (passive PFC) and active correction technology (active PFC). The passive correction technique is simple, but the circuit must have large inductance or capacitance, and the power factor after correction can not be very high

active power factor correction can be divided into two types: one is a two-stage structure, and the other is a single-stage structure. The two-stage structure can adopt many topologies, but the boost power factor correction circuit is the most widely used at present, with high power factor (0.99) and low total harmonic distortion (5%). The disadvantage of this circuit is that it requires many components and high cost. In order to reduce the number of components and reduce the cost of electronic ballast, PFC circuit and load circuit can be combined into one level. The main advantages of single-stage power factor correction are high power factor, simple structure and low cost. Its main disadvantage is that the PFC circuit is associated with the load circuit, and the circuit design is more complex, so it is a hot spot in the field of power electronics

3 single-stage power factor correction electronic ballast

in principle, power factor correction can be realized by inductance and capacitance. Single stage PFC electronic ballasts can therefore be divided into three categories

3.1 single stage power factor correction electronic ballast with inductor [2-8]

single stage power factor correction with inductor can be divided into three types: boost converter, buck converter and buck boost

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