DC-DC (direct-current to direct-current) resonant converter with automatic voltage equalizing function

Abstract

The invention discloses a DC-DC (direct-current to direct-current) resonant converter with an automatic voltage equalizing function. The DC-DC resonant converter comprises a switch capacitor circuit and an LLC (logic link control) series resonant circuit. The switch capacitor circuit is formed by concatenation of a plurality of half-bridge submodules. Middle nodes of two adjacent half-bridge submodules are connected through a switch capacitor module. According to the DC-DC converter, the half-bridge submodules are in series connection before being connected in parallel at two ends of a direct-current power supply. In the ideal case, the voltage of each bus capacitor is one n-th of the direct-current voltage; two switch tubes are in series connection inside one half-bridge submodule before being connected in parallel with one bus capacitor, and accordingly turn-off voltage stress of each switch tube is half of the voltage of one bus capacitor. Switch components with low voltage and high performances can be selected for the converter, efficiency of the converter is improved, and size of the converter is reduced.

Description

Technical field [0001] The invention belongs to the technical field of power conversion, and specifically relates to a DC-DC resonant converter with an automatic voltage equalization function. Background technique [0002] In recent years, various power supply devices have been widely used in communications, lighting, military and other industries. In order to regulate the power quality of power equipment, some worldwide academic organizations and countries have begun to formulate and implement a series of standards for power equipment. It is one of the important standards to limit the harmonic pollution of power equipment to the AC grid, such as IEC555-2, IEEE519, etc. In order to meet the harmonic standards, multi-stage cascaded high-frequency converters are usually used in the industry, and power factor correction technology (Power Factor Correction, PFC) is used in the first-stage rectifier equipment. [0003] When using a multi-stage cascaded high-frequency converter in a th...

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Problems solved by technology

However, the stress of the primary switching tube of the traditional half-bridge LLC series resonant structure is the input voltage; and due to the low switching frequency and large on-resistance of high-voltage devices, the converter cannot meet the needs of high efficiency and high performance, and the cost of high-voltage devices is relatively high. ; moreover, as the demand for high step-down applications increases, the size of the transformer will increase, resulting in higher losses and lower power density

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