| Buck-Boost DC-DC converter is a basic topology of DC-DC converter, can realize pressor step-down, and input voltage and output voltage reversed-phase as a reversed-phase converter. To improve the behavior of Buck-Boost DC-DC converters, a digital current following control approach based on the microprocessor to realize is described in this topic. The output current, the output voltage and the input voltage are measured, based on which, and according to the gain of the feed back voltage basis, the desired averaged inductor current is worked out and the inductor current is controlled to a narrow range around it, by outputing high and low level to control switch. Elaborated the digital current hysteresis control method theorys .The dynamic performance in case of the input voltage changing and the load changing is deduced. The design considerations are given. An example is given to show the parameter design steps. Experiments are made on the example. The influence on the output voltage when the input voltage and the load suddenly changes are tested. The results of the experiments show that the proposed approach is feasible and the analysis is correct, the converter meets design index. |
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