Disturbance-Observer-Based Control for Dual-Stage Grid-Tied Photovoltaic System under Unbalanced Grid Voltages

Rachid Errouissi, Ahmed Al-Durra

Research output: Contribution to journalArticlepeer-review

45 Scopus citations


This paper presents the design and experimental validation of disturbance observer (DO)-based control for grid-tied photovoltaic (PV) inverters fed by a dc-dc boost converter considering unbalanced grid voltages. The control scheme uses multiples controllers that are developed based on employing DO technique along with a feedback-linearizing (FBL) control. The main controller is designed to regulate the active and reactive powers injected into the grid via controlling the grid-tied inverter. Under unbalanced grid voltages, the active and reactive power is composed of a dc component as well as an ac component that oscillates at twice the grid frequency. Therefore, the unknown perturbation, representing the mismatch between the nominal and actual system, can be treated as a sum of a constant offset and a sinusoidal disturbance. To ensure accurate control of the active/reactive power, a DO is designed to estimate the unknown perturbation, which is then canceled by a FBL control. By considering the control input limitation in the observer synthesis, an antiwindup compensator arises naturally in the control law, which attenuates the effect of the windup phenomenon during control saturation. Moreover, a simplified representation of the DO is proposed to facilitate real-time implementation. The proposed approach for the power control can be used in both balanced and unbalanced systems since it can reject constant and sinusoidal disturbances. Experimental tests were performed to investigate the ability of the proposed control scheme to achieve good transient and steady-state performances.

Original languageBritish English
Article number8533618
Pages (from-to)8925-8936
Number of pages12
JournalIEEE Transactions on Industrial Electronics
Issue number11
StatePublished - Nov 2019


  • Antiwindup scheme
  • Disturbance observer (DO)
  • Grid-tied inverter
  • Low-voltage ride through (LVRT)
  • Nominal performance recovery
  • Photovoltaic (PV) system
  • Sinusoidal disturbance rejection


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