Method and apparatus for detecting input current of bridgeless PFC circuit

Abstract

The invention relates to a method and an apparatus for detecting an input current of a bridgeless PFC circuit. The method comprises the following steps of connecting a positive-half-cycle diverter unit in series in a positive-half-cycle loop of a bridgeless PFC branch and connecting a negative-half-cycle diverter unit in series in a negative-half-cycle loop of the bridgeless PFC branch, detecting voltages cross the two sides of the positive-half-cycle diverter unit and the negative-half-cycle diverter unit respectively, and thus calculating the input current through the bridgeless PFC circuit. Through connecting the positive-half-cycle diverter unit and the negative-half-cycle diverter unit in series in the positive-half-cycle loop and the negative-half-cycle loop of the PFC circuit respectively and by detecting the voltages of the two sides of the positive-half-cycle diverter unit and the negative-half-cycle diverter unit, an inductor current through the PFC circuit can be calculated simply, conveniently and effectively, timely sampling of the input current can be realized and a sampling difficulty of the input current through the bridgeless PFC circuit can be reduced.

Description

technical field [0001] The present invention relates to an input current detection method and device, more specifically, to a bridgeless PFC circuit input current detection method and device. Background technique [0002] Active Power Factor Correction (APFC, Active Power Factor Correction) is widely used in communication power supplies. In the control of APFC, it is necessary to sample the AC input current. In the bridgeless PFC circuit (especially, the totem pole bridgeless PFC circuit) directly Sampling AC input current is difficult. At present, there is no relatively simple, convenient and effective current sampling scheme for a bridgeless PFC circuit operating in a continuous current mode (CCM, Current Continuous Mode). Contents of the invention [0003] The purpose of the present invention is to provide an input current detection device for a bridgeless PFC circuit, which aims to solve the difficulty of directly sampling the AC input current in a bridgeless PFC circ...

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Problems solved by technology

[0003] The purpose of the present invention is to provide an input current detection device for a bridgeless PFC circuit, which aims to solve the difficulty of directly sampling the AC input current in a bridgeless PFC circuit in the prior art; there is no relatively simple, convenient and effective Aiming at the problems of the current sampling scheme of the bridgeless PFC circuit working in the current continuous mode

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