A Hybrid Control Method for Resonant Converter in Distributed Power System

Abstract

The invention provides a hybrid control method for a resonant converter in a distributed power system. The distributed power system adopts a two-pole topology structure, the front stage is a step-up power factor correction stage, and the rear stage is a DC-DC conversion stage. A connection capacitor is connected between the two stages, and the DC-DC conversion stage adopts a full-bridge LLC resonant converter; it is characterized in that: in normal mode, the full-bridge LLC resonant converter works in the state of a half-bridge resonant converter, and the resonant The operating frequency of the converter is equal to the resonant frequency, and the resonant converter works at the resonant frequency point, and the efficiency of the resonant converter is the largest; when the AC input voltage is lost, the full-bridge LLC resonant converter is in the holding mode, and the full-bridge LLC resonant converter adopts Based on the hybrid control of pulse width modulation and pulse frequency modulation, high voltage gain adjustment is realized, the input voltage working range of the resonant converter is widened, and the output voltage of the load remains unchanged.

Description

technical field [0001] The invention relates to a hybrid control method of a resonant converter, in particular to a resonant converter applied to a distributed power system (DPS), and belongs to the technical field of power electronic converters. Background technique [0002] The front stage of the commonly used distributed power system (DPS) is a step-up power factor correction stage (PFC), so that the power factor is 1, and the current harmonic distortion is reduced. At the same time, the input AC voltage is converted into a DC voltage, which is used as the input of the subsequent circuit Voltage. The latter stage is a DC-DC conversion stage (DC-DC), which precisely adjusts the output voltage and supplies power to the load equipment with a constant voltage. An intermediate connection capacitor (C link ). [0003] A key feature of a distributed power system (DPS) is the retention time requirement. When the input voltage at the AC input terminal of the step-up power factor...

AI Technical Summary

Problems solved by technology

However, when the input terminal of the resonant converter operates in a wide voltage range, it is necessary to adjust the switching frequency away from the resonance point, which leads to a decrease in the performance and efficiency of the resonant converter

The current related research adds auxiliary switching power devices or changes the control mode of the resonant converter to make the resonant converter meet the requirements of hold-up time characteristics. These methods increase the design cost and control complexity

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