| DC/DC converters are widely used in every field of our daily life and play an important role.In some special application fields,such as new energy power generation,mine power supply,military equipment power supply,all require DC/DC converter to meet the requirements of wide input voltage range.When the input range of the DC/DC converter becomes wider,it will lead to an increase in the loss,a greater demand for heat dissipation,and a lot of adverse effects,such as efficiency,power density,life and reliability degradation.For this reason,the wide input range DC/DC converter and its efficiency improvement method are studied in this paper.The four switch Buck-Boost(Four-Switch Buck-Boost FSBB)as a wide input range of main circuit of DC/DC converter topology,elaborates the basic derivation,the principle of FSBB,the gain characteristics;control method of FSBB converter are studied in detail,the FSBB synchronization control of double tube control,control of the five goes along a hard switching control method and soft switching of synchronous control,ZVS control,Buck-Boost improved ZVS Buck-Boost control three control methods of soft switch driver timing,soft switching conditions,working modes are analyzed;in order to improve the proportion of direct power FSBB converter as the criterion,by means of theoretical analysis and modeling combined loss the wide input range of three mode control strategy of FSBB converter;the three modes of FSBB converter based on the small signal model of closed-loop control The system is designed and closed loop simulation is performed with PLECS software.The static and dynamic characteristics of the three modes are tested to verify the correctness of the controller parameter design.Finally,making a prototype of 50-400 V input,200V/2A output,the wide input range of 1:8 under the basic functional verification,three mode switching,soft switching and efficiency test of FSBB converter,verify the correctness of the theoretical analysis and design. |
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