Non-intrusive parameter estimation method for autotuned DC-DC converter based on quasi-impulse response

A non-intrusive method to estimate the values of power-stage components online and autotuning of feedback compensator for digitally controlled power converters is presented in this study. By using buck converter as an example, the presented autotuning controller has been designed to cover the wide-range variations in equivalent series resistance zero of the output capacitor and the resonant frequency of output filter . These two frequencies are estimated by examining the converter's quasi-impulse response during start-up and by measuring the output-voltage ripple during steady-state operation of the converter. Hence, due to the non-intrusive characteristic of the proposed control method, the operation of the converter is not affected. Using the acquired results, the online digital compensator is tuned automatically based on predefined crossover frequency and phase margin to provide the required output-voltage regulation and transient response under wide-range variations in the power-stage component values. To validate the effectiveness of the proposed control method, experimental results from a 12 to 1.5V buck converter are presented.