A Novel Wide Output Range Multi-Mode LLC Resonant Converter

With the advancement of science and technology,in order to meet more application occasions,whether it is in the industrial field or the transportation field,higher requirements are put forward for the adjustable range of the input and output voltage of the DC-DC converter.Therefore,the research work on DC-DC converters with wide input/wide output voltage range has also attracted more and more researchers’ attention.In this context,this paper proposes a new type of LLC circuit,and combines it with double interleaved The parallel BOOST circuit is cascaded,and the characteristics of the two circuits are used to realize the wide input and wide output voltage range of the overall DC-DC circuit.First,the application status and application background of DC-DC converters are introduced,and then three common DC-DC converters are briefly compared,including:non-isolated,isolated and wide input/output voltage range isolated DC-DC converters.DC converter,considering the demand for DC-DC converter with wide voltage range in various production and living fields,the main work of this paper is to study this kind of converter and propose a new topology.Secondly,the working principles of the front stage and the back stage of the proposed circuit topology are introduced respectively.The front stage is a new type of LLC circuit.The working principle of the circuit is introduced emphatically,and the working principle of the re-interleaved parallel Boost circuit of the latter stage is also analyzed.Same as the traditional LLC circuit,the fundamental frequency component method is also used to model and theoretically analyze the proposed new LLC circuit.The working characteristics of the new LLC circuit in the steady state are mainly analyzed,and the circuit input is also derived.and the relationship between the output voltage and the relationship between the output voltage,and its relational expression was deduced,and then the influence of the selection of different component parameters in the new LLC circuit and BOOST circuit on the overall circuit operating characteristics,such as resonant inductance,resonant capacitance,etc.,and then calculated The appropriate component parameters of the overall circuit(new LLC circuit + BOOST circuit)are selected,and the components are selected according to the calculated parameters.Then,the designed hardware circuit is introduced,and several key auxiliary circuits used are introduced in detail,such as power supply,driving and sampling circuits.The power supply circuit ensures the normal operation of each chip in the auxiliary circuit,and the driving circuit is the main circuit switch.The turn-on and turn-off of the tube provides the required drive signal,while the sampling circuit samples the output voltage,resonance current and other parameters to meet the control needs.On the basis of the introduction of the hardware circuit design,it also controls the circuit The method is introduced in detail,mainly including the fixed frequency control method commonly used in traditional LLC circuits,and the proposed minimum loss control strategy and coordinated control strategy.Finally,through the simulation software and the experimental platform,the proposed circuit and control strategy are simulated and verified by experiments,and the results of the simulation and experiments are analyzed.