Topology Research On An Improved Z-Source DC-DC Converter

Under the triple background of rapid economic development,increasingly scarce fossil energy and increasingly serious environmental problems,the requirements for new energy technologies are increasing.Switching power supplies,as a device for power transmission and conversion,can rapidly develop new energy technologies.Application and promotion provide strong support.Today,the government is constantly adjusting subsidy policies in areas such as new energy vehicles,rural photovoltaic power generation,and wind power generation,and strives to expand the proportion of new energy in industrial production and people’s daily life.Among them,DC power supply will play an indispensable role,and DC-DC converter as the connection point between DC power supply and load has become a long-standing research hotspot in this field.Therefore,it is of great theoretical significance and great practical value to study a DC-DC converter with simple circuit structure,excellent performance and good economy.At present,DC-DC converters mainly have defects such as small boosting factor,high voltage stress of capacitor,limited voltage regulation range,and low working efficiency.Based on the Z-source DC-DC converter,the switch-inductor and switched-capacitor booster modules are focused on the topological research of the main circuit.An improved Z-source DC-DC converter is proposed.The converter retains the Z-source symmetric network and inherits some of the advantages of the Z-source converter to meet the current demand for miniaturization and economy of the power supply.Refer to the Z source converter analysis method to analyze the working principle,control method and working performance of the new topology.The column writes the expression corresponding to the equivalent circuit diagram in different states,and derives the capacitor voltage,the average inductor current,and the voltage gain.Taking the improved type Ⅱ Z source converter as an example,the small-signal modeling is done by the state average method and the small disturbance method for the impedance source network.According to the transfer function and the zero-pole graph,the influence of network device parameters on its static performance and dynamic performance is analyzed,which can provide an optimal solution for network device selection and achieve stable boost function.Not only is it advantageous to achieve miniaturization of the converter,but also to improve its economy.The Matlab/Figure software visually demonstrates the difference between the improved topology and the original topology,demonstrating the significant advantages of the improved converter.Then,through the way of cascading unit modules on the improved converter,the multi-stage cascaded Z-source converter is explored,and the conclusion that the increase of the unit module can increase the voltage gain and reduce the average current and capacitance of the inductor is obtained.Finally,using Matlab/Simulink software to simulate the proposed converter,combined with the experimental setup of the converter,and the experimental data of the test prototype under the on-duty ratio,the simulation data,experimental data and theoretical values.A comparison was made.Within the allowable range of error,the theoretical analysis of the improved type ⅡZ-source converter,the correctness of the formula derivation,and the feasibility of practical application are proved.