Research On Dynamic Modeling Method Of Complex Switch Resonant Converter

Dynamic modeling for the switching power converter is the key to design a switching power supply system. For switching resonant converters with complex circuit structure and working process, such as ACPDC and FPRDC, it's very difficult to obtain their accurate models by existing methods, which greatly hampered the further research for the switching power converter.The thesis is primarily focuses on dynamic modeling method for the complex switching resonant converter. Considering that the circuit structure and working process of the converter are complex, a new modeling method called parameters of difference equations fitting algorithm is proposed from the perspective of system identification, which is applied to small-signal modeling for the complex switching resonant converter.The method regards complex switching resonant converter as a black box, only with the input and output data of the black box for modeling. So it can avoid the direct analysis of the converter's work mechanism and makes starting modeling for the type of converters easier.Moreover, this method has the same way of modeling for the PWM switching power converter and the PFM switching power converter.Compared with the former modeling methods, it reduced the difficulty particularly, especially for small signal modeling of the PFM switching power converter. Firstly, the paper analyses various part of the switching power supply and their models, focuses on the switching power converter's circuit characteristics. On this basis, a new modeling method is proposed. A detailed introduction of the method's algorithm, steps and applications in small-signal modeling for the PWM and PFM switching power converters are presented.Secondly, models of Buck, Boost, Buck-Boost and Cuk converters are established by the new method. From comparing them with models established by state-space averaging method, we can get models using the new method are much more precise than models using state-space averaging method. Then, models of ACPDC type of PWM and FPRDC type of PFM are successfully obtained by the new method. The successful applications show that the new method not only applies to PWM switching power converters, but also for PFM switching power converters, The successful applications also show that the new method not only applies to simple switching power converters, but also for complex switching resonant converters,Finally, a model identification software, which is operated easily and can be reused for power supply designers, was programmed.