This paper aims to improve the performance of five- level neutral-point-clamped-based (FL-NPC) shunt active power filters (SAPFs) that employ the direct current regulation (DCR) strategy for compensating nonlinear loads. In the DCR strategy, a main controller, which is usually a PI controller, is required to regulate the DC-bus voltage and, simultaneously, provide the reference current, while a modulation technique is used to generate the desired reference current. An adaptive PI-type fuzzy logic controller (A-PI-FLC) and an adaptive hysteresis current control (AHCC) are proposed to advance the DCR operation by providing fast DC-bus voltage regulation and modulating the reference current with a predefined constant switching frequency particularly in transient conditions, respectively. However, their superior performance may be jeopardized when voltage-type faults (sags/swells) emerge in the power system. These faults can interfere in the DC-bus voltage control and, in turn, deteriorate the modulation performance, which ultimately lead to degrada- tion of the SAPF performance. Thus, a supplementary controller (SC) is proposed and included in the control system to protect it from these faults. Extensive simulation studies are presented to validate the outstanding performance of the proposed control approaches in enhancing the performance of FL-NPC SAPFs.