Accurate state estimation in DC-DC converters using a Proportional-Integral Observer (PIO)

Abstract

This paper focuses on state estimation of DC-DC converters in the presences of a biased duty-cycle which is very common in practice. It is shown that the commonly used Proportional (P-) observer fails to estimate the state of the converter when an unknown biased duty-cycle is present. To address this issue, a Proportional-Integral (PI-) observer is proposed, and its design is formulated as a H ∞ /L 2 problem. A sufficient condition is derived by using the Lyapunov stability theorem and linear-matrix-inequality (LMI) design tool, guaranteeing the convergence of the observer's estimation error. The effectiveness and robustness of the proposed technique is verified and is compared with the P-observer observer through an experimental test on a step-down buck converter.

Immersion and invariance-based filtered transformation with application to estimator design for a class of DC-DC converters

“…High reliability, low cost and high efficiency make sensorless current mode control an application of interest in academy and industry (Moreno-Valenzuela et al, 2016). Since for each system, one nonlinear observer needs to be allocated owing to the bilinear essence of power converters, and the problem of existing various configurations for variant power levels, the literature looks forward to finding the ways to address these issues (Alavi et al, 2014; Foley et al, 2012; Malekzadeh et al, 2018; Qahouq et al, 2011; Seo et al, 2014). Accordingly, control schemes with direct actuation are hard to be applied.…”