Impact Factor:5.967
DOI number:10.1109/TPEL.2021.3055369
Journal:IEEE Transactions on Power Electronics
Key Words:Active thermal balancing (ATB), asymmetrical duty-cycle control (ADCC), dead-time compensation (DTC), hybrid modulation schemes, soft switching, three-phase dual-active bridge
Abstract:The three-phase dual-active-bridge (DAB) converter is a promising topology for high-power dc–dc conversion in dc grids and industrial applications. However, the conventional single-phase-shift modulation shows a limited soft-switching range and large reactive currents under light-load operation especially with large voltage variations. This article proposes an asymmetrical duty-cycle control method for the three-phase DAB to extend the soft-switching range and reduce reactive currents by realizing three-phase triangular- and trapezoidal-current-mode operation. Closed-form solutions of the proposed modulation schemes are derived that enable a simple online calculation of the control parameters. The proposed modulation schemes can substantially reduce losses of both power semiconductor devices and the medium-frequency transformer. Thus, the three-phase DAB converter can realize high efficiency over a wide operation range, especially under light-load conditions. Considering the practical implementation, a compensation method is presented to correct the distorted current waveforms caused by the dead time and ensure the desired soft-switching operation. Besides, the power loss imbalance between top and bottom switches induced by the asymmetrical duty cycle is addressed by an active thermal balancing strategy. The effectiveness of the proposed method is validated by simulation results and experiments on a downscaled converter prototype.
Indexed by:Journal paper
Discipline:Engineering
Document Type:J
Volume:36
Issue:8
Page Number:9609-9622
ISSN No.:0885-8993
Translation or Not:no
Date of Publication:2021-01-28
Included Journals:SCI
Links to published journals:https://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=63