Research On Improved Pulse Train Controlled Boost DC/DC Converters

With the continuous promotion of the national "dual carbon" strategy,highperformance boost DC/DC converters have been widely used in new energy generation,electric vehicles,and other applications.Due to the relatively slow dynamic response of traditional pulse width modulation(PWM)technology,pulse train(PT)control has gradually received attention.Compared to PWM control,PT control has the advantages of simple structure,good compatibility,and fast transient response.However,in the continuous operation mode of the inductor current of the converter,there is a problem of voltage regulation delay in the PT controlled converter,which leads to a low frequency oscillation of large output voltage,and the power quality is difficult to meet the requirements.In order to solve the problem of low frequency oscillation in PT controlled boost DC/DC converters,this thesis studies corresponding solutions.Firstly,the causes of low frequency oscillation in the CCM of the PT controlled Boost converter are analyzed,and improved methods are studied from both topology and control aspects.The mechanism of the improved method to suppress low frequency oscillation is analyzed,and the feasibility is verified through simulation and experiments.Secondly,a high gain boost converter topology with coupled inductors is studied.According to the conduction condition of each switching device in the circuit,its operating mode and voltage gain and switching stress under open loop control are analyzed,the influence of coupling inductance parameters on both is discussed,and the reason for low frequency oscillation of this high gain topology under PT control is explained.Simulation and experimental results are given.Finally,a coupled inductor primary side current feedback PT control method is proposed to solve the low frequency oscillation problem of high gain converters.The working principle of the improved method is analyzed,and the working mode of its filter circuit is described.The parameter values of each component in the filter circuit are designed,and a synchronous switch mapping model is established.Simulation and experiments also verify the feasibility of this improved method.There are 46 figures,6 tables and 86 references in this thesis.