Model-Based and QRESO-Based Predictive Compensation Active Damping With Capacitor-Voltage Feedback for Current Source Rectifier

The introduction of control delay alters the characteristics of capacitor-voltage feedback (CVF) active damping (AD), which cause performance degradation and system stability issues. Meanwhile, ensuring the robustness and disturbance rejection capability of current source rectifiers (CSRs) against grid-side LC filter parameter variations or load disturbances remains a significant challenge. For the above problems, this article proposes two delay compensation methods, the AD combined with model predictive control (MPC) and quasi-resonant extended state observer (QRESO)-based predictive compensation method. Both methods have been proven effective in extending the stable domain of the AD feedback gain by predicting the capacitor voltage one step ahead. Furthermore, in comparison with the MPC scheme, the QRESO-based predictive compensation method can further enhance the suppression of periodic disturbances. Finally, the experimental results validate the proposed methods, confirming their effectiveness as per the theoretical analysis.