High-power factor correcting circuit

Abstract

The invention relates to a high-power factor correcting circuit, which comprises a rectifying bridge DB11, a switch transformer, two switch tubes Q12 and Q11, three capacitors C11, C13 and C12, and five diodes D11, D12, D13, D14 and D15, wherein the switch transformer is provided with three groups of primary coils which are a first primary coil L11, a second primary coil L12 and a third primary coil L13, and one group of secondary coil. When alternating current is at a peak value and nearby, the electrical energy transformed by the transformer is mainly from the rectified alternating current, and the electrical energy stored in a transformer leakage inductor and the rectified alternating current are used as the charge electrical energy of the energy storage capacitor C13 together. When the alternating current is at a wave trough and nearby, the electrical energy stored in a circuit (the capacitor C13) is transformed into the transformer transformation electrical energy, and the electrical energy stored in the transformer leakage inductor and the rectified alternating current are used as the charge electrical energy of the capacitor C13 together.

Description

technical field [0001] The present invention relates to power supply technology, in particular to a single-stage power factor correction power supply circuit Background technique [0002] In the power grid, various loads, especially nonlinear loads, have a significant impact on the grid power supply. For example, the power supply of many electrical appliances needs to convert the alternating current of the grid to direct current. The pulsating current generated during the rectification process contains a large number of current harmonic components. These harmonic components flow back into the grid, which will cause harmonic "pollution" to the grid. When the current flows through the line impedance, it will cause a harmonic voltage drop, making the sinusoidal The wave grid is distorted. [0003] At present, my country enforces "CCC certification" for home appliances (CCC certification is "China Compulsory Certification". To meet the requirements of this standard, various ho...

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Problems solved by technology

[0007] This method can be called the active power and factor correction method. This circuit connects a DC / DC switching converter between the rectifier and the load, applies current discharge and feedback technology, and is controlled by a PFC dedicated logic chip to make the current waveform at the input end Tracking the AC input sinusoidal voltage waveform throughout the electrical cycle, this active power factor correction circuit can make the input current close to sinusoidal, so that the total harmonic distortion (THD) at the input end is less than 5%, and the power factor can be increased to 0.99 % or even higher, the problem with this circuit is that this power factor correction circuit increases the circuit loss due to the addition of a first-stage circuit, and at the same time, due to the increase in the voltage of the stage, the voltage parameters of the subsequent switch tube devices increase, thereby increasing the cost.

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