NOVEL CONTROL DESIGN FOR THE BUCK CONVERTER

A novel control design approach for average current-mode controlled bu ck converters is presented. The buck converter large-signal averaged m odel is shown to be easily large-signal linearisable, The linear model is then examined as a multivariable system with no inner and outer lo ops, using both the state-space and frequency domain descriptions, Tra nsfer functions of the system are derived as a function of the desired closed-loop poles, simplifying the design procedure and bringing forw ard all the important characteristics of the closed-loop system, Sever al advantages can be gained by the use of capacitor current instead of inductor current feedback, Theoretical analysis is applied and confir med with simulation and experimental results on a 250 W prototype, The proposed approach can be used with all small-signal linear models of DC-DC converters, offering simplicity and a better insight on system c haracteristics.