| DC-DC converters are used in DC power conversion to meet the requirements of different loads, such as in information, communication, energy and other key fields.With the development of industry and technology, the function and performance requirements of DC-DC switching power supply become more and more stringent.Compared with traditional analog control, digital control method not only has the characteristics of high flexibility and programmability, but also can adopt more advanced control algorithms to improve the performance of converter. Therefore,from analog control to digital control will become the develop trend of switching converter in future.In this paper, Buck converter is taken as an example to simulate and verify the models of analog and digital DC-DC converters, and the digital adaptive compensation control method is studied and analyzed. The work includes:The operation process of DC-DC converter is analyzed under different modes, and its continuous-time model is built. In addition, the non-ideal Buck converter with parasitic parameters is modeled and analyzed.A discrete z-domain model which considers sampling, holding and quantization is established and analyzed. The adaptive compensation control method is adopted to improve stability, reduce system error and delay, and improve transient performance when the load changes.The adaptive compensation control algorithm is used to simulate, optimize the digital DC-DC converter model by Matlab/Simulink. Besides, the performances at steady state and transient state are also analyzed. Simulation results show that the system output voltage keeps stable at 5V, the transient response time is about 0.22ms with the switching frequency from 100KHz to 1MHz, which verifies the correctness of the control method. |
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