Digital Current Hysteresis Loop Controlled For Boost DC-DC Converters

In recent years, with the rapid development of power electronic technology, the switching power supply which constructed by DC-DC converter has been applied in every field deeply. As for the switching DC-DC converter control, using analog PWM control usually. The traditional analog controller is hard to guarantee the nonlinear DC-DC converter running with an ideal control performance, comparing with the analog controller, digital controller can be easily realized the complicated nonlinear control strategy which could essentially improve the DC-DC converter controller performance. At present, the maturation of DSP hardware technology make it possible to realize digital controller for DC-DC converter, in power electronic study field, the study of nonlinear control strategy for DC-DC converter become very pop.To improve the behavior of boost DC-DC converters, a current following control appoach is discribed. The input voltage, the output voltage and the output current 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 PWM generator outputing high and low level to control switch. The dynamic performance in case of the load changing and the starting period is deduced. The design considerations are given.An example is given to show the parameter design steps. Experiments are made on the Boost converter based on ARM7-LPC2138. 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.