Analysis of DC Voltage Ripple in Grid-Connected Inverters under Unbalanced Disturbances in Weak Grids
Year: 2026
Type: conference-paper
Abstract: Voltage unbalance in the power grid can cause twice-frequency ripple in the DC capacitor voltage of grid-connected inverters, which affects their lifespan and control performance. In weak grid conditions, the dynamic interaction between the inverter and the grid is intensified, leading to deviations in traditional calculations for DC voltage ripple, potentially resulting in improper DC capacitor design. To address this, a small-signal model is developed by analyzing the propagation path of unbalanced disturbances between the inverter and the weak grid. This model accurately quantifies both the transient and steady-state ripple magnitudes of the capacitor voltage following unbalanced disturbances. Additionally, constraint surfaces for capacitor values under transient/steady-state ripple limits are calculated. Finally, Controller-hardware-in-the-loop experiments validate the accuracy of the proposed model. The findings provide clear boundary conditions for DC capacitor design, enhancing the safety and reliability of inverter grid-connected operations.
Authors: Mingyuan Liu, Chengxi Liu, Zhaoming Liu
Language: English
Subfield: Control and Systems Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
OpenAlex ID: W7214199091