Multivariable DC Bias Control of a High Power AC-DC Dual-Active-Bridge Based Converter

• Published in: IEEE transactions on power electronics Vol. 38; no. 11; pp. 1 - 9
• Main Authors: de Araujo, Jose W. M., Honorio, Dalton de A., Oliveira, Demercil de S.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.11.2023; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: AC-DC converters; AC-DC power conversion; Bias; Bridge circuits; Control systems design; Current control; Current measurement; Electric bridges; Electric converters; Hall effect; Lyapunov methods; Magnetic cores; Mathematical models; Multivariable control; Pulse width modulation; Resistance; Robust control; State feedback; Topology; Voltage control; Windings
• ISSN: 0885-8993; 1941-0107
• DOI: 10.1109/TPEL.2023.3302228

This paper addresses the dc magnetization issue in high-power single-stage dual active bridge (DAB) - based converters. A multivariable control strategy capable of simultaneously regulating the dc bias currents is applied to an integrated ac-dc topology. The control approach relies on two input variables, the magnetizing current, and the secondary current dc offset; and two outputs, that is, the duty cycles applied to the primary-side and secondary-side switches. The currents are measured by Hall sensors comprising several samples to average the offset values. The locations of samples and the measurement accuracy are discussed to validate the acquisition concept. The transformer is modeled using state-space equations and the controllers are tuned using state feedback associated with an augmented system to achieve robust reference tracking and disturbance rejection. The controller is designed based on the Lyapunov equation. Experimental results are presented and discussed to validate the control strategy applied to an integrated ac-dc converter rated at 8.33 kW. Steady-state and dynamic results show that the introduced solution can eliminate the dc bias of all currents even during load changes, without significantly affecting the harmonic content of the ac input current.