| Title |
Operating Frequency Design for Stable Initial Operation of Loosely Coupled Resonant DAB Converter |
| Authors |
Seung-Hyuk Baek ; Sungmin Kim ; Jaehong Lee ; Seung-Hwan Lee |
| DOI |
https://doi.org/10.6113/TKPE.2021.26.6.437 |
| Keywords |
SST (Solid-State Transfome); DAB (Dual-Acive-Bridge) converter; LCR (Looesly coupled resonant) DAB converter; WPT (Wireless Power Transfer); IPT (Inductive Power Transfer) |
| Abstract |
This paper proposes an operating frequency design method that limits the voltage applied to aload-side converter during the initial operation of a loosely coupled resonant dual-active bridge (LCR-DAB) converter and an initial operating strategy that applies it. The LCR-DAB converter uses two wireless power transfer coils instead of the high-frequency transformer of the general DAB converter. The wireless power coil has a physical distance of several tens of millimeter or more between the two coils; thus, the LCR-DAB converter is a bidirectional isolated power conversion system that can easily achieve high insulation performance. However, for the initial operation of the LCR-DAB, if the power-side converter is operated at the resonance frequency while the load-side converter is not operating, then a very high voltage due to resonance is applied to the load-side converter, thereby causing damage to the converter. Therefore, a method that can stably charge the DC link voltage of the secondary-side converter during the initial operation is needed. This paper proposes a method to initially charge the secondary-side DC link by operating the primary-side converter at a frequency with limited voltage gain rather than at a steady-state operating frequency. The validity of the proposed frequency design method and initial operating sequence is verified through simulation and experimentation of the 1 KW LCR-DAB converter. |