Single-stage type isolated AC-DC converter based on interleaved bridgeless PFC circuit and LLC resonance

Abstract

The invention provides a single-stage type isolated AC-DC converter based on an interleaved bridgeless PFC circuit and LLC resonance. The single-stage type isolated AC-DC converter comprises a front-stage interleaved bridgeless PFC circuit for converting an AC input voltage to a DC voltage, a primary side of a back-stage full-bridge LLC resonance circuit is of a full-bridge circuit structure, theoriginal side can realize switching tube zero-voltage soft turning-on, and a secondary side can realize diode zero current-current soft turning-off. The converter reduces the number of switching tubes, thereby improving the efficiency of the whole converter. The AC / DC part of the converter is an interleaved bridgeless PFC circuit, and two paths of input inductive currents are interleaved, so thatinput current ripples are greatly reduced; the converter can enable input current change to well follow input voltage to change, and realizes a power factor correction function; by controlling outputvoltage, the converter realizes stable DC voltage output; and at the same time, the converter has a high-frequency transformer, and can achieve electric isolation.

Description

technical field [0001] The invention belongs to the field of power electronics and specifically designs a single-stage isolated AC-DC converter based on an interleaved parallel bridgeless PFC circuit and LLC resonance. Background technique [0002] With the development of communication technology, electric vehicles and power systems, higher requirements are put forward for the performance, weight, volume, efficiency and reliability of switching power supplies for communications, electric vehicle chargers and electric operating power supplies. Power supplies in these fields Usually, the DC power is output from the AC grid, and considering the impact on the power quality of the grid and safety, the converter is required to have the functions of power factor correction and electrical isolation. [0003] The traditional bridge power factor correction circuit (commonly known as Boost PFC) has more power semiconductor devices through which current flows at the same time, and the e...

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Problems solved by technology

However, the two-stage circuit uses more devices, the cost is higher, and the volume is larger.

[0006] Y.Wang and Y.Guan et al. titled ASingle-Stage LED Driver Based on Interleaved Buck-Boost Circuit and LLC Resonant Converter (IEEE Journal of Emerging And Selected Topics in Power Electronics,2015,3(3),pp.732-741 ) proposed a single-stage converter based on Buck-Boost and LLC, which has the functions of power factor correction and electrical isolation, and can realize soft switching of power devices; however, the front stage of the circuit uses The bridge rectification structure has a large conduction loss; at the same time, the input current of the circuit is in a discontinuous mode, and the current ripple in this mode is large

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