High-frequency active power factor correction of switching power supply of large-screen color TV

Improve the power factor PF Use a energy-conserving important factor of electrical equipment. With the development of electric electron technology, high-frequency active power factor correction PFC Technology has already been more and more applied to various power widely. The power of switching power supply of large-screen color TV is among 200 300W, the original color
High-frequency active power factor correction of switching power supply of large-screen color TV - schematic

electric switching power supply is adopted and commutated ordinarily with the smoothing circuit, its composition of harmonic current is large, the power is low because of the number value, it is generally 0. 65~ 0. 85. In order to improve the electrical properties of electric festival of large screen color, we adopted high-frequency active PFC technology in the design, have improved PF characteristic. It is obvious, can also be defined as the product of distortion factor and phase shift factor. To switching power supply, cos generally approaches 1, namely phase shift is not big, but the harmonic current is serious, the distortion factor is small. The ones that use the electrical equipment PF low, apt to cause the following to endanger: Harmonic current pollute electric wire netting seriously, interfere with, spend the electrical equipment while being other; The mean value of input current is heavy, need to increase the specifications of circuit and protective device; The capacity increases to supply power, strengthen the preceding stage apparatus such as voltage transformer Quota; Have increased the load of central line greatly, has reduced safety performance. High-frequency active PFC is PWM signal emerges according to the voltage, electric current and change that supports of the electric wire netting, ones that control the high-frequency electronic beam switch to be turned on, can play a role in regulating the inductance...

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