A Modified PBC Controller for LCL‐Filtered Grid‐Tied DC/AC Inverter With Enhanced Control Performance

ABSTRACT Passivity‐based control (PBC) has been employed as a nonlinear control method in LCL‐filtered grid‐tied DC/AC inverters (GTIs). However, theoretical analysis has proven that the conventional PBC (C‐PBC) technique heavily depends on the accurate mathematical model of the controlled system. This leads to a steady‐state error, as well as degradation of the dynamic performance under the condition of parameter drift. To address these issues and in response to existing research focused on improving the power quality of the grid‐tied system, enhancing control performance, and optimizing system dynamic response, a new modified PBC (M‐PBC) controller for LCL‐filtered GTIs is proposed. The dynamic damping injection (DDI) technique is utilized to eliminate the steady‐state error. Furthermore, due to the simple feedback coefficient and effective damping effect, the capacitor current feedback (CCF) active damping loop is also designed to achieve a better dynamic response. Finally, the state observer technique is adopted to reduce sensors and save industrial costs. The detailed analysis process is presented and the performance comparison between the C‐PBC and M‐PBC is carried out. A simulation platform is constructed in MATLAB/Simulink and a 3‐kW experimental prototype system is built using dSPACE of DS1202 to validate the proposed controller's feasibility and effectiveness.