A Phase Control Method of Interleaved Parallel Totem Pole Bridgeless PFC

Abstract

The invention discloses a phase control method of interleaved parallel totem pole bridgeless PFC. The period value is higher than the period value corresponding to the minimum switching frequency of the switching tube; the PWM count value when the main phase in the master-slave phase triggers the zero-crossing detection signal of the inductor current is captured by the DSP processor, and recorded as the first count value; through the DSP processor Capture the PWM count value when the slave phase in the master-slave phase triggers the zero-crossing detection signal of the inductor current, and record it as the second count value; adjust the conduction time of the switching tube on the master-slave phase through the first count value and the second count value. The master-slave phases of the two-phase or multi-phase interleaved parallel connection of the present invention are all controlled by frequency conversion, and each phase realizes zero-current opening, and at the same time, the phase control greatly reduces the system input current ripple and improves the efficiency of the whole machine.

Description

technical field [0001] The invention relates to the field of power factor correction, in particular to an interleaved parallel totem pole bridgeless PFC phase control method. Background technique [0002] In order to improve the power factor and reduce the harmonic content of the input current, a power factor correction (Power FactorCorrection, PFC) circuit is widely used in power electronic equipment. The traditional PFC interleaved parallel technology is to parallel the input and output of two or more PFC circuits with the same structure. The working signal frequency of each PFC unit is the same, and the phase angles of the switch tubes are staggered from each other by a fixed angle, such as two phases staggered by 180 degrees. , so that the input current ripple is partially or completely offset, greatly reducing the input current ripple. Traditional power factor correction circuits generally adopt fixed-frequency PWM control, and make the circuit work in a continuous con...

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Problems solved by technology

However, in the case of staggered parallel frequency conversion work, the realization of 180-degree interleaving is relatively complicated compared to fixed frequency work. The reason is that the switching frequency at different times in a mains power frequency cycle is actually different, and because of the differences in the components of the circuit itself, The current zero-crossing moment of the interleaved parallel power devices is not exactly the same. If only the main phase is controlled, the PWM of the slave phase has a fixed interval and a fixed angle phase relationship, instead of the zero-crossing detection of the inductor current of the slave phase (ZeroCurrent Detection, ZCD) signal triggers the control, so the moment when the slave phase switch is turned on may not be zero-voltage turn-on or valley-bottom turn-on, and lower switching losses cannot be guaranteed

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