Nonlinear design and stability analysis with experimental validation of cascaded pi controlled dc/dc boost converters

Nonlinear proportional-integral cascaded controllers that guarantee stability are proposed for the challenging problem of regulating the output voltage of dc/dc boost power converters. In order to examine whether the proposed controllers can achieve stable operation, a novel stability analysis is introduced, which incorporates the advanced nonlinear concept of input-to-state stability and exploits the cascaded structure of the closed-loop system. This new methodology succeeds in proving asymptotic stability of the complete closed-loop system, under the only constraint of selecting negative feedback-loops. However, since the cascaded controller design is based on the time-scale separation assumption, a systematic tuning method is conducted for the accurate gain selection of both the inner-loop and outer-loop controllers. Finally, the theoretical analysis and the system performance are fully verified by simulation results which are further validated by experimental tests.