AC/DC power supply system and control method thereof

Abstract

The invention discloses an AC / DC power supply system which comprises an AC power supply, a power factor correction (PFC) circuit, a control circuit, a bus capacitor, a switching circuit, a DC / DC isolating power stage, an output capacitor and an output load, wherein inputs of a PFC module are the AC power supply; an output of the PFC module is bus voltage; an input of the switching circuit is the bus voltage; outputs of the switching circuit are four terminals; the terminals by two groups are respectively connected with two input ends of a DC / DC module; and output ends of the DC / DC module are connected in parallel, and supply power to the output capacitor and the load. The control circuit sets output voltage of the PFC module according to an effective value or a peak value of detected inputvoltage, and controls operation of the PFC circuit according to a detection signal Vbus_s and a PFC sampling signal, so that a PFC function and bus voltage Vbus stabilization are achieved. In addition, the control circuit controls the switching circuit to change a connection manner of the DC / DC module according to an effective value or a peak value of detected input voltage, or directly changes an operation mode of backward-stage DC / DC by a control signal, so that the power supply system operates in an optimal operation state.

Description

technical field [0001] The invention relates to power electronic circuits, in particular to an AC-DC power supply system. Background technique [0002] Ignoring the EMI filter block, figure 1 Shown is a traditional AC-DC power supply system, a bridge rectifier circuit 11 converts the AC input into a DC voltage to supply a Boost converter 12, and the Boost converter provides a power factor correction (PFC) function to meet industry standards or simply ground to convert the voltage with large fluctuations to a stable voltage or a voltage range with a small variation range, and the subsequent DC / DC converter 13 converts the output voltage of the Boost converter to the voltage required by the load and supplies it to the load 14 , and achieve the role of isolation. Usually, the AC input range is 85-265VAC. When the output of the Boost converter is 400V, we call it a regulated PFC, and when the output voltage is 200-400V, we call it a follower PFC. In terms of the performance a...

AI Technical Summary

Problems solved by technology

And considering the two typical power supply standards in the world, that is, some countries represented by China have a mains power supply standard of 220VAC, while other countries represented by the United States have a mains power supply standard of 110VAC, so the same power system It is difficult to work in the optimal working state under two voltage input conditions

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