Wide input range dual-bridge LLC resonant converter

Abstract

The invention discloses a wide input range dual-bridge LLC resonant converter, and belongs to the technical field of electric power electronic transformation. The inverter comprises an input direct current voltage source Vin, bus dividing capacitors Cin1 and Cin2, switch tubes Q1, Q2, Q3, Q4, Q5 and Q6, a resonant capacitor Cr, a resonant inductor Lr, a magnetic inductor Lm, a transformer T, rectifier diodes D1 and D2, an output filter capacitor Co and a load Ro. By controlling the ratio between the time that the converter works in full-bridge and the tome that the converter works in half-bridge working in one period, an input voltage waveform of a resonant groove is changed, and thus adjusting the output of the inverter is realized. The inverter adopts constant-frequency PWM control, switching frequency is equal to resonant frequency, primary side current is decreased, and conduction loss is reduced. The inverter can realize primary side main switch tube ZVS opening and secondary side rectifier diode ZVS turn-off in a full-input-voltage scope and a full-load-change scope, reduces switching loss, and increases watt intensity. The wide input range dual-bridge LLC resonant converter has the advantages of wide input voltage range, constant-frequency control, benefit for magnetic device design and optimization, and the like.

Description

technical field [0001] The invention relates to a power electronic conversion technology, in particular to a double-bridge LLC resonant converter with a wide input range. Background technique [0002] With the increasingly serious problems of environmental pollution and energy shortage, people pay more and more attention to renewable energy. The forms of renewable energy power generation mainly include photovoltaic power generation, wind power generation, hydropower generation and fuel cell power supply, etc., all of which have the characteristics of wide output voltage range. Therefore, in order to efficiently utilize renewable energy and reduce energy waste, a DC / DC converter capable of operating in a wide input voltage range is required. [0003] At present, the traditional LLC resonant converter can realize zero-voltage switching (zero-voltage switching, ZVS) of the main switch in the full load range, and the secondary rectifier diode can realize zero-current shutdown, ...

AI Technical Summary

Problems solved by technology

However, the traditional LLC resonant converter adopts frequency conversion control. When the input voltage range is wide, the frequency range of the converter is also wide, which is not conducive to the design and optimization of magnetic components; The gain has a great influence. In the wide input voltage range, the value of the excitation inductance is limited, which is not conducive to the reduction of the excitation current of the primary side.

Therefore, traditional LLC resonant converters are not suitable for wide input voltage range applications

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