An Active FTC Strategy Using Generalized Proportional Integral Observers Applied to Five-Phase PMSG based Tidal Current Energy Conversion Systems

Abstract

In recent years, multi-phase permanent magnet synchronous generators (PMSGs) have become attractive in the field of tidal current energy conversion systems (TCECS) due to their high-power density, reliability, and availability. However, external disturbances and malfunctions in power conversion chains will bring challenges to achieving stable and continuous tidal current energy harnessing. Using generalized proportional integral observers, an active fault-tolerant control (AFTC) strategy is therefore proposed for a five-phase PMSG based TCECS that is subjected to an open switch fault (OSF) in the generator side converter. This proposed AFTC strategy is applied into q-axis current control loops, which contain fault detection and compensation. The fault compensator will be smoothly activated using a sigmoid function once the OSF is detected. Finally, a small-scale power experimental platform emulating the TCECS is established in order to verify the feasibility and efficiency of the proposed FTC strategy. Experiment results show that this AFTC strategy can detect faults rapidly and effectively attenuate torque ripples in the post-fault operation mode.

ESO-based FTC strategy via dual-loop compensations for 5-phase PMSG integrated tidal applications

“…This paper utilizes an optimal TSR-based MPPT [28], which provides desired speed and mechanical torque references as Eq. ( 7) below.…”

An FTC Design via Multiple SOGIs with Suppression of Harmonic Disturbances for Five-Phase PMSG-Based Tidal Current Applications

“…V carrier , the amplitude of carrier signals, is set as 1. The controller parameters [15] in inner current loops can be given by:…”

“…It is worth pointing out that this work provides a more flexible design and it is independent to system modelling, via a compensation mechanism of selective harmonic, compared with our recently published model-based FTC strategy [15]. Compared with notch-filters-based [24] and proportional-resonant-based methods [25], this multiple SO-GIs based strategy is convenient for designing multi-resonant compensators for online implementations with less parameter setting.…”

“…Regarding the popular hybrid solutions around the studied issue in this paper, there emerged several representative research works. Liu et al [15] designed an active FTC strategy combining fault status and fault compensation based on a disturbance observer-based method. The fault compensation can handle all the situations theoretically that characterize the features of passive FTC.…”

“…The PMSG contains trapezoidal back-electromagnetic forces (back-EMFs), and the single-phase open condition is investigated carefully. Different from the usage into grid synchronizations as [18], multiple SOGIs innovatively characterize the model-free fault estimator by extracting the main harmonic disturbances, relative to the similar model-based fault estimators [15,[19][20][21][22][23].…”