A novel control strategy for grid connected distributed generation system to maximize power delivery capability

Highlights: • A novel control strategy is proposed to maximize power delivery capability. • The power flow and power sharing are achieved with a power management strategy. • A current limiter is embedded into the reference current generator for overcurrent. • Minimization and controllability of active-reactive power oscillations are performed. • A sequence extractor is proposed to achieve fast response and to reduce harmonics. -- Abstract: The energy sector is moving toward an extensive utilization of hybrid renewable energy resources (HRES), which are commonly interfaced to the utility grid through the inverters. Therefore, the proper operation of the grid connected inverter has brought major requirements under unbalanced grid faults. In this regard, this paper proposes a novel control strategy to maximize power delivery capability of the grid connected inverter interfaced distributed generation (DG) systems. The proposed control strategy achieves power flow and power sharing among DG units, the utility grid and load demand with a power management system. Minimization and controllability of active-reactive power oscillations are fulfilled with a flexible control parameter. An improved positive and negative sequence extractor (PNS) is proposed to separate sequence components for use in the reference current generator. The proposed PNS extractor provides a significant improvement in terms of response time as less than one period-(18 ms) compared to existing techniques. The proposed control strategy achieves also high performance with lower total harmonic distortion about 0.5%. Another novelty of this paper is that a current limitation control is inserted into the reference current generator for overcurrent protection. Comparative evaluation of the proposed control strategy is performed and confirmed under various cases.