Gain frequency modulation method and related device

Abstract

The embodiment of the invention provides a gain frequency modulation method applied to a flying capacitor type half-bridge three-level LLC resonant converter and a related device, and the method comprises the steps: controlling the flying capacitor type half-bridge three-level LLC resonant converter to be switched between a high gain frequency modulation mode and a low gain frequency modulation mode according to different input and output voltages; when the input voltage is high and the output voltage is low, enabling the resonant converter to work in a low-gain frequency modulation mode. Forthe same input voltage, the peak-to-peak value of the LLC resonant cavity input voltage of the flying capacitor type half-bridge three-level LLC resonant converter in the low-gain frequency modulationmode is less than the peak-to-peak value of the LLC resonant cavity input voltage in the high-gain frequency modulation mode, so that the gain of the circuit is reduced. By changing the frequency modulation mode, the gain range of the flying capacitor type half-bridge three-level LLC resonant converter is expanded.

Description

technical field [0001] The present invention relates to the technical field of three-level LLC topology, and more specifically, relates to a gain-frequency modulation method and a related device of a flying capacitor type half-bridge three-level LLC resonant converter. Background technique [0002] In high-voltage applications, a three-level LLC topology can be used to reduce the voltage stress of the switch tube. The flying capacitor type three-level LLC topology uses a small number of clamping components and has strong automatic voltage equalization capability without additional voltage equalization control. It has very good application value in high voltage and wide gain range occasions. Flying-span capacitor type half-bridge three-level LLC resonant converter, the input voltage divider capacitor C d1 and C d2 , flying capacitor C k , switch tube Q 1 ~Q 4 , transformer T, excitation inductance L m , Resonant inductance L s , Resonant capacitance C s , rectifier di...

AI Technical Summary

Problems solved by technology

For wide voltage range applications, when the circuit’s maximum input voltage V in_max The required gain is less than G min , the flying capacitor type half-bridge three-level LLC resonant converter cannot output the required voltage value

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