Non-linear cascade control of DC/DC Buck converter

A model-based cascade controller design is presented for the control of DC/DC Buck converters. Detailed discussions in the setting of bandwidth for the current loop and voltage loop have been given. Robustness analysis of the cascade controller against load changes and supply changes are also presented. Finally, a deadband relay is introduced in the voltage loop to improve the disturbance rejection and speed of response of the Buck converter. Circuit implementation of the proposed control scheme is presented, and experimental results are included to demonstrate the effectiveness of the proposed design scheme. Comparisons with conventional single-loop proportional-plus-integral control and cascade control are also made.