Master–slave current regulation of an LCL-filter-based grid-connected inverter under variable grid condition

Abstract

To ease the heavy burden of inverter control, including line current regulation, harmonic current suppression, filter resonance suppression, grid distortion suppression, phase locked loop etc., the study proposes a master–slave current regulation method for an LCL-filter-based grid-connected inverter operating under variable grid condition. The proposed system is composed of a grid-connected voltage-source inverter (GC-VSI) in series with a bidirectional voltage-source converter (B-VSC) at the inverter output. The GC-VSI is responsible for line current regulation, while the B-VSC takes charge of harmonic current suppression and grid impedance cancellation. Owing to low volt-ampere of the B-VSC, the efficiency of the inverter system is not sacrificed. To confirm its validity, a simulation platform with the proposed inverter system has been built. The simulation results demonstrate the performance enhancement of the proposed inverter system operating under different grid conditions.

Keywords

• electric current control
• phase locked loops
• invertors
• power grids
• voltage-source convertors
• power conversion harmonics
• harmonics suppression
• inverter control
• line current regulation
• harmonic current suppression
• filter resonance suppression
• grid distortion suppression
• phase locked loop
• master–slave current regulation method
• variable grid condition
• grid-connected voltage-source inverter
• gc-vsi
• bidirectional voltage-source converter
• b-vsc
• inverter output
• grid impedance cancellation
• lcl-filter-based grid-connected inverter
• inverter system
• grid conditions