TY - GEN
T1 - Low-Frequency Oscillation Suppression in Series Resonant Dual-Active-Bridge Converters under Fault Tolerant Operation
AU - Pan, Yiwei
AU - Yang, Yongheng
AU - He, Jinwei
AU - Sangwongwanich, Ariya
AU - Blaabjerg, Frede
PY - 2019/9
Y1 - 2019/9
N2 - When an open-switch fault occurs in the inverter-side of the series resonant dual-active-bridge (SRDAB) converter, the rectified DC voltage will drop by a half. One solution to maintain the continuous power supply of the converter is to regulate the duty-cycle of the rectifier output voltage. Nevertheless, it may excite the resonance between the resonant inductors and the DC capacitors and lead to severe low-frequency oscillations, which appears as the envelope of the high-frequency current. This phenomenon may trigger the over-current protection and make the SRDAB fail to ride through the fault. In this paper, a low-frequency equivalent model is proposed for the SRDAB, enabling frequency-domain analysis of the conventional single-loop voltage control. It is revealed that the oscillation depends on the duty-cycle and control parameters, and it is not possible to suppress such oscillations by the conventional control method. Thus, a dual-loop fault tolerant control method consists of an outer voltage control-loop, an inner current envelope control-loop. Also a non-linear correction unit is proposed to suppress the oscillation. Experimental tests on a 1-kW SRDAB are performed. The test results have validated the effectiveness of the proposal in terms of oscillation suppression.
AB - When an open-switch fault occurs in the inverter-side of the series resonant dual-active-bridge (SRDAB) converter, the rectified DC voltage will drop by a half. One solution to maintain the continuous power supply of the converter is to regulate the duty-cycle of the rectifier output voltage. Nevertheless, it may excite the resonance between the resonant inductors and the DC capacitors and lead to severe low-frequency oscillations, which appears as the envelope of the high-frequency current. This phenomenon may trigger the over-current protection and make the SRDAB fail to ride through the fault. In this paper, a low-frequency equivalent model is proposed for the SRDAB, enabling frequency-domain analysis of the conventional single-loop voltage control. It is revealed that the oscillation depends on the duty-cycle and control parameters, and it is not possible to suppress such oscillations by the conventional control method. Thus, a dual-loop fault tolerant control method consists of an outer voltage control-loop, an inner current envelope control-loop. Also a non-linear correction unit is proposed to suppress the oscillation. Experimental tests on a 1-kW SRDAB are performed. The test results have validated the effectiveness of the proposal in terms of oscillation suppression.
KW - Photovoltaic (PV) systems
KW - Inverters
KW - Maximum power point tracking (MPPT)
KW - Interharmonics
KW - Power quality
KW - Series resonant converter
KW - Dual-active-bridge (DAB) converter
KW - Fault tolerant control
KW - DC distribution systems
KW - Oscillation suppression
UR - http://www.scopus.com/inward/record.url?scp=85076765923&partnerID=8YFLogxK
U2 - 10.1109/ECCE.2019.8913130
DO - 10.1109/ECCE.2019.8913130
M3 - Article in proceeding
SN - 978-1-7281-0396-9
T3 - IEEE Energy Conversion Congress and Exposition
SP - 1499
EP - 1505
BT - Proceedings of 2019 IEEE Energy Conversion Congress and Exposition (ECCE)
PB - IEEE Press
T2 - 2019 IEEE Energy Conversion Congress and Exposition (ECCE)
Y2 - 29 September 2019 through 3 October 2019
ER -