Low-complexity, high frequency parametric system identification method for switched-mode power converters

Online system identification provides the possibility to track system changes and thus is the basis for successive adaption of control parameters. This paper introduces a concept for fast, efficient and accurate coefficient estimation of time-discrete transfer functions. The presented approach approximates least squares and, compared to well established algorithms, it drastically reduces the computational-complexity, while maintaining sufficient accuracy. In the experimental setup this technique has been applied to a dc-dc buck converter. For this application the proposed method is especially beneficial, since it significantly reduces the system excitation time compared to the state-of-the-art. This is achieved by using higher switching frequencies, while keeping the amount of used switching periods constant. Consequently, the proposed concept can be integrated into the start-up procedure of the converter module.