Steady‐state hybrid extended Kalman filter based sensorless voltage controller for a phase‐shifted full‐bridge converter

Abstract

This study proposes a steady‐state hybrid extended Kalman filter‐based control method for sensorless output voltage regulation of a phase‐shifted full‐bridge DC/DC converter. Unlike the conventional applications, there are some specific cases where the voltage feedback needs to be received indirectly. For example, in wireless power transmission applications, obtaining a “continuous” and real‐time feedback without relying only on wireless communication could significantly advance the systems' performance and robustness. Specifically, in this paper, a method that can estimate the output voltage feedback as well as load resistance in real‐time for sensorless voltage control is proposed. The approach in this study relies on estimating the output voltage using processed primary current measurement. Although the exemplary converter system is modelled in discontinuous conduction mode (DCM), the method can also estimate the load resistance and provide a stable operation in continuous conduction mode (CCM). However, for very low load resistances which cause limit states such as current control limit or duty cycle limit, method cannot estimate the load resistance properly. Throughout the paper, the modelling framework is first introduced and then the design of the proposed sensorless voltage control scheme is presented. Finally, the algorithm's performance is verified through experimental studies.