Quantum mechanics

Control (management)

Voltage

Engineering

Capacitance

Aerospace engineering

Film capacitor

Electrolytic capacitor

Biology

Materials science

Computer science

Grid

Single stage

Computer network

Capacitor

Paleontology

Physics

Link (geometry)

Mathematics

Stage (stratigraphy)

Electronic engineering

Artificial intelligence

Geometry

Electrode

Control theory (sociology)

Photovoltaic system

Equivalent series resistance

Electrical engineering

IEEE Access

Single-stage utility-scale photovoltaic (PV) systems are usually interfaced with the host grid via a centralized voltage-source converter (VSC).Recently, and due to their reliability, the dc-link film capacitors are favored over electrolytic types in grid-connected applications.However, the capacitance per unit volume of film capacitors is significantly smaller than electrolytic capacitors.The overall system stability might be compromised by the reduction of the dc-link capacitance, particularly in PV systems that have a dynamic resistance that varies with operating conditions.Using a detailed small-signal model of the grid-connected PV system, it is shown in this paper that the reduction of the dc-link capacitance interferes with the dynamic resistance of the PV array, which eventually leads to instabilities.The minimum dc-link capacitance that preserves the overall system stability is determined.A simple and effective active compensator is developed to mitigate the instabilities with the reduced dc-link capacitance.Detailed time-domain simulations are presented to validate the analytical results and show the proposed compensator's effectiveness in preserving the system stability.

Assessment and Mitigation of Dynamic Instabilities in Single-Stage Grid-Connected Photovoltaic Systems With Reduced DC-Link Capacitance