Research On New Wide Input LLC Converter Based On Server Power Supply

With the progress of the times,the development of various industries is dependent on the Internet,so the demand for data center and energy consumption is also increasing.The DC/DC converter in the server power supply is an inseparable part.Compared with the shift phase topology,the LLC resonant converter has gradually become the preferred topology of the server power supply.However,this kind of power supply has the key problem of hold-up time,so it needs the ability of the converter to have a wide input voltage range.Because the LLC converter under traditional frequency modulation control is not suitable for wide input applications,this thesis proposes a new wide-input LLC resonant converter,which can increase the LLC converter gain under fixed frequency conditions.Firstly,the thesis analyzes the traditional LLC converter,explains its working mode and its realization of soft switching principle in detail,and uses FHA to obtain the gain equivalent model and voltage gain function.Uses Math CAD software to draw the relevant gain curve to,in order to study the influence of each parameter of the circuit on the gain of the converter.According to the gain characteristics of the LLC converter during FM control,it can be seen that there are many problems such as excessive switching frequency range and harsh parameter design.As a result,it is difficult for the traditional LLC converter to be suitable for wide input voltage working occasions.Based on the traditional half-bridge LLC converter circuit,this paper proposes a new wideinput LLC resonant converter circuit topology.The converter adds an auxiliary circuit on the basis of the circuit of the traditional half-bridge LLC converter.The auxiliary circuit is composed of two switch tubes and diodes.After the auxiliary circuit works,relatively more energy can be injected into the resonant tank within a certain period of time.The gain of the converter can be increased,so that the gain can be adjusted under the condition of fixed frequency.This thesis introduces the working principle of the converter and its working mode,and approximately calculates its voltage gain characteristics according to its working principle.Then,a hybrid control strategy suitable for the converter is proposed,which can realize that the voltage gain of the converter is continuous when the two modes are switched,and the circuit model of the converter is built with the help of Matlab/Simulink software platform to verify its effectiveness by simulation.Finally,the paper designs the hardware circuit and control system of the converter,and introduces the design ideas and process of the system in detail.On this basis,this paper designs an experimental prototype to further verify the feasibility of the converter working at a wide input voltage.The thesis summarizes the research content that has been carried out and gives a further outlook.