A PFC control method based on pseudo-coupled power frequency inductance without zero current detection

Abstract

The invention relates to a PFC control method based on a pseudo-coupling power frequency inductance and without zero current detection. The interleaved and parallel PFC working in a critical mode comprises the following steps: inputting the voltage of a power device into a single-chip microcomputer, and comparing it with a preset value in the single-chip microcomputer. Compare the theoretical voltage values, output a zero-current trigger signal, and turn on the PWM; the single-chip microcomputer outputs a trigger signal to turn off the PWM, and the single-chip microcomputer enters an external interrupt to trigger the single-chip analog-to-digital converter. At this time, the single-chip microcomputer respectively collects two windings on the false coupling inductor The current value, input voltage value, output voltage value, and coil temperature; compare the collected current value with the theoretical current value, run the compensation algorithm, get the compensation value and compensate the inductance of the winding; then according to the two false coupling inductance The temperature and current value of each winding are used to judge whether to run the protection algorithm. The control method provided by the present invention can avoid false triggering caused by leakage inductance and parasitic capacitance caused by the magnetic coupling method.

Description

technical field [0001] The invention relates to the technical field of power supply, in particular to a PFC control method based on a pseudo-coupled power frequency inductor and without zero current detection. Background technique [0002] In the field of alternating current applications, due to the existence of the DC bus capacitor, it will cause the peak of the input current, generate a large number of harmonics, reduce the power factor, and affect the stability of the mains. Therefore, a power factor correction circuit must be used, and the critical mode PFC is a kind of power factor correction circuit. The advantage of low cost. However, the peak current of the device is large and the input current ripple is high. [0003] In the patent titled: "Method and Device for Implementing a Multi-Mode Power Factor Corrector" (Application No.: 201010177415.8, Application Publication Date: 2010.10.13), an embodiment of the present invention provides a multi-mode power factor corr...

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Problems solved by technology

[0004] The above-mentioned patent mentions that an auxiliary winding is added to the PFC inductor, and the zero-current signal is triggered by detecting the voltage at the output end of the auxiliary winding, which will incur additional costs, and the influence of the temperature of the inductor cannot be ignored, and a DC bias will occur ; At the same time, the auxiliary winding can be wound in the coupling inductor by magnetic coupling, but because the coupling coefficient cannot be idealized, there are leakage inductance and parasitic capacitance, these parameters will cause oscillation, interference and voltage spikes, affecting zero current control signal accuracy, causing false triggering

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