| In fire emergency lighting power supply and other low voltage applications, battery is used tosupply power, however, as the battery’s voltage will decrease gradually with its discharge, a DC/DCconverter with wide range input voltage is required. Buck converter is selected as the main topologyof the power system.This paper studies the basic principle of Buck DC/DC converter, then analyses Buck circuit’stwo kinds of work mode: continuous conduction mode (CCM) and discontinuous conduction mode(DCM), it also analyses the critical condition of two kinds of work mode; the small signal analysismethod is used in the modeling of the Buck main circuit to obtain the transfer function of theconverter from the control to the output, then the whole Buck converter system is analyzed to deducethe open-loop transfer function in detail, and its properties are studied. Meanwhile, Matlab softwareis used to analyze the stability of Buck converter in the frequency domain, also the Bode method isused to determine the stability of the system and design the compensation network-PIDcompensation network, and the stability of the network have been improved.Finally, according to the given parameters of the converter system，and theauxiliary power supply circuit is designed. Pspice is used to simulate the main circuit,and the main circuit is simulated by Saber, the simulation results proved that thesystem meets the stability requirements; at the same time, the production ofexperimental circuit is completed according to the design scheme, and the test resultsshow that the design parameters and compensation network of Buck DC/DC convertermeet the requirements, it also verifies the feasibility of the scheme. |
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