Publication:
Self-synchronizing stationary frame inverter-current-feedback control for lcl grid-connected inverters
Self-synchronizing stationary frame inverter-current-feedback control for lcl grid-connected inverters
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Date
2022-04-01
Authors
Ahmad Afif Nazib
Holmes D.G.
McGrath B.P.
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Publisher
Institute of Electrical and Electronics Engineers Inc.
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Abstract
Current regulation of inductive-capacitive-inductive (LCL) grid-connected inverters usually requires multiple current sensors to actively damp the filter resonance. Inverter-side current regulation avoids this issue because of its inherent LCL filter damping properties but does not accurately control the grid-side current, particularly with distorted grids. Furthermore, both strategies typically require high-quality voltage sensors to maintain precise grid synchronization. This article proposes a novel current control strategy for LCL grid-connected inverters that only requires inverter-side current sensors. The strategy uses the resonator output states of a stationary reference frame (SRF) proportional resonant (PR) current regulator to estimate the grid voltage phase and filter capacitor current and, thus, achieve self-synchronized indirect regulation of the grid-side current. The effectiveness of the approach has been verified using simulation and matching experimental investigations.
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Keywords
Grid synchronization,
grid-connected inverter,
LCL,
proportional resonant (PR) controller