A wide gain range llc resonant converter and its control method

Abstract

The invention relates to a wide gain range LLC resonant converter and a control method thereof. The converter includes an inverter circuit, an LLC resonant cavity, a transformer and a rectification network; the LLC resonant cavity includes resonant inductors Lr, Lm and resonant capacitor Cr; the LLC resonant cavity A bidirectional switch is also added inside; the resonant capacitor Cr and the resonant inductance Lr are serially connected in series between the No. 1 output terminal of the inverter circuit and the 1 terminal of the primary coil of the transformer, and the No. 2-terminal connection, the resonant inductance Lm is connected in parallel with the primary coil of the transformer, the 1 terminal of the bidirectional switch is connected to the 1 terminal of the primary coil of the transformer by connecting between the resonant capacitor Cr and the resonant inductance Lr, and the 2 terminal of the bidirectional switch is connected to the primary coil of the transformer The two ends of the coil are connected; the inverter circuit is a variable topology circuit combining a full bridge / half bridge. The present invention greatly expands the gain range of the present invention through the transformation of the topology structure of the full bridge / half bridge, and the circuit structure of the present invention reduces the difficulty of designing the converter.

Description

technical field [0001] The invention relates to the technical field of switching converters, in particular to an LLC resonant converter and a control method thereof. Background technique [0002] The field of power electronics is developing rapidly, and switching converters are used more and more widely. People place more demands on switching converters: high power density, high reliability and small size. As a kind of resonant converter, LLC resonant converter has many advantages, such as low noise, low stress, and low switching loss. LLC resonant converter generally adopts two working modes of variable frequency control and fixed frequency control. However, when the input voltage and load vary widely, the operating frequency of the LLC resonant converter using variable frequency control alone varies widely, which makes the magnetic Component design is difficult, and when the voltage gain is wide, the efficiency of the traditional variable frequency control LLC resonant c...

AI Technical Summary

Problems solved by technology

However, it still belongs to frequency conversion control, and the design of magnetic components is still relatively complicated.

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