The Research On The Control Of Multi-module Hybrid DC-DC Converter

With the development of energy conversion technology,power electronic technology has also got a strong concern and rapid development,and the power electronic equipment is also concentrated in the system of high frequency,circuit modules and integration.The hybrid converter combined by the multi-module converters is also a hot topic.There are two forms of combination.One is the series-parallel connection with the same converter in the input and output sides in the application of different voltage and current.The other is the combination of different converters to improve the defects in a single circuit and combine the different advantages of several converters.The integration of modular converters possesses the benefits of redundant operation capability,standardized modular manufacturing and flexibility of power extension.Among them,ISOP modular configuration can offer a solution to use low voltage ratting switches in high input-voltage and low output-voltage applications.To ensure the feasibility of ISOP modular converters,the power must be shared equally among individual modules(IVS and OCS).The centralized control of ISOP has been researched widely,which could limit the reliability and expansibility of systems.In view of the above problems,the paper discussed the decentralized anti-droop control of converters in detail.With the control,OCS and IVS can be both well achieved.In this thesis,the analysis of the two-transistor forward converter using the PWM control strategy and bidirectional half-bridge DC-DC converter using the phase shift control is given.Then,ISOP modular current-fed bidirectional DAB converters using the PPS and decentralized control are analyzed.The control strategy and small signal model are described in detail to analyse the stability of the system.Last,the prototype is built to verify the control in the power electronic transformer or soild state transformer(SST).