Small-Signal Modeling of the PVR-Based AD Scheme and Controller Design for Three-Phase Standalone DG System

Abstract

-This paper presents the small-signal state-space modeling and a new multifunctional multi-loop control strategy for three-phase inverter-based islanded DG systems under unbalanced and/or nonlinear load conditions. The proposed control methodology utilizes the parallel virtual resistance (PVR)-based active damping (AD) method for the islanded DG system using an extra feedback capacitor current shaping loop in the stationary reference frame to provide an AD to suppress the resonance-peak of the LC filter and improve both steady-state and transient performances, the inner voltage and current controllers are based on an enhanced proportional resonant (PR) structure to achieve zero steady-state error, and multi-resonant harmonic compensator (MRHC) plus PR controller to prevent low-order load current harmonics to distort the output voltage. The proposed small-signal model of the islanded DG system with multi-loop control strategy in the stationary reference frame is presented. Moreover, an enhanced delay compensation (EDC) scheme based on two integrators of the discrete PR controller is presented to improve stability margins with a higher accuracy compared with the existing methods. Then, a detailed systematic controller parameters design procedure is presented. Finally, simulation and experimental results are provided to validate the effectiveness of the proposed strategy.

Small Signal Modeling of Inverter-based Grid-Connected Microgrid to Determine the Zero-Pole Drift Control with Dynamic Power Sharing Controller

“…Renewable energy sources are attracting more and more attention [1][2] due to the limited resevers of non-renewable resources. Power electronic converters are commonly used to interface distributed sources and grid to a microgrid (MG) which can operate either on islanded or grid-connected mode [3][4][5]. The small signal state space modelling of MG is the best way to observe its performance.…”

Sine phase compensation combining an amplitude phase controller and a discrete feed-forward compensator for electro-hydraulic shaking tables

“…To compensate the time varying delays with uncertain processes, Norrney-Rico et al (2012) proposed a discrete dead-time compensators on the basic of the Smith predictor. Besides, a discrete proportional resonant controller was employed to compensate the system delay (Shen et al, 2016b).…”