Isolation type integrated AC-DC converter on basis of bridgeless PFC (power factor correction) and LLC (logic link control) resonance

Abstract

The invention discloses an isolation type integrated AC-DC converter on the basis of bridgeless PFC (power factor correction) and LLC (logic link control) resonance. The isolation type integrated AC-DC converter is characterized by comprising a preceding-stage bridgeless totem-pole PFC circuit and a backward-stage half-bridge LLC resonance circuit; the preceding-stage bridgeless totem-pole PFC circuit is used for converting alternating-current input voltages into direct-current voltages; the backward-stage half-bridge LLC resonance circuit is connected with the preceding-stage bridgeless totem-pole PFC circuit in parallel; a primary side of the backward-stage half-bridge LLC resonance circuit is of a half-bridge circuit structure and is used for implementing zero-voltage flexible switching, and a secondary side of the backward-stage half-bridge LLC resonance circuit is of a full-bridge rectification structure and is used for rectifying alternating-current voltages into direct-current output voltages. The isolation type integrated AC-DC converter has the advantages that input currents can effectively change along with the input voltages, and accordingly the isolation type integratedAC-DC converter has a power factor correction function; the output voltages can be controlled by the isolation type integrated AC-DC converter, and accordingly the stable direct-current output voltages can be outputted.

Description

technical field [0001] The invention belongs to the field of power electronics, in particular to an isolated integrated AC-DC converter based on bridgeless PFC and LLC resonance. Background technique [0002] With the development of communication technology, electric vehicles, and LEDs, higher requirements are placed on the performance, weight, volume, and efficiency of switching power supplies for communications, electric vehicle chargers, and LED drivers. The power supply in these fields usually takes power from the AC grid to output DC, and requires the converter to have the functions of power factor correction and electrical isolation at the same time. [0003] The common power factor correction circuit (PFC) is a bridge Boost PFC circuit, but the current of the bridge Boost PFC circuit flows through three power devices at the same time, and the conduction loss is relatively large; with the development of semiconductor power devices, especially the wide With the develop...

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Problems solved by technology

[0004] Y.Wang and N.Qi et al. proposed a SEPIC and LLC Circuits-based LLC's single-stage converter, which has the function of power factor correction and electrical isolation at the same time, can realize the soft switching of power devices; however, the front stage of this circuit still adopts bridge rectification structure, which increases the conduction loss ; At the same time, the input current of the circuit is discontinuous mode, and the current ripple is relatively large

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