Grid integration of multiple PV inverters with reduced number of interfacing transformers- A dedicated controller for elimination of DC current injection
Document Type
Article
Publication Date
3-1-2023
Abstract
The injection of dc current offset into ac networks may impacted the lifespan of the distribution system equipment including isolation transformers and measurement devices and in serious event may cause equipment's malfunction. This paper intents to eliminate dc current offsets in the output currents using a combinational of proportional-integral (PI) and proportional resonance (PR) controls embedded in one inverter unit. Resultant output currents of this method are sinusoidal and clean from dc offset before entering the point of common coupling. This method gives advantages for transformerless option for group of interfacing inverters in the medium-scale solar farm or in arrangement of inverters restricted in a small locale. Moreover, the use of expensive and high-accuracy measurement sensor nor complex transformer can be omitted, whilst indirectly give positive impact to the operational cost of the farm. The simulation verifications proved the usefulness of the proposed method by introducing varying unknown dc offset levels in the phase currents, and a dedicated dc offset suppressor inverter able to successfully eliminate the dc offset to zero. The validity of the proposed method is demonstrated in simulation using MATLAB/Simulink. (c) 2022 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Keywords
DC offset, DC current suppression method, Grid interfacing inverter, PR control
Divisions
umpedac
Funders
Ministry of Education, Malaysia,MOHE, Malaysia under Fundamental Research Grant Scheme (FRGS) (Grant No: FRGS/1/2020/TK0/UNIMAP/02/100)
Publication Title
Energy Reports
Volume
9
Issue
1
Publisher
Elsevier
Publisher Location
RADARWEG 29, 1043 NX AMSTERDAM, NETHERLANDS
Additional Information
9th International Conference on Power and Energy Systems Engineering (CPESE), Doshisha Univ, Kyoto, JAPAN, SEP 09-11, 2022