Hybrid ADRC and PI Controller Design for Three-Phase Inverter With Nonlinear Loads

With the widespread application of power electronic devices in industrial and residential settings, the performance of three-phase inverters under nonlinear loads has garnered significant attention. Nonlinear loads pose significant challenges due to their complex behavior, which can adversely affect power quality and system stability. This paper aims to propose a dual closed-loop control strategy for three-phase inverters under nonlinear loads to enhance stability, dynamic response, and robustness. The control strategy employs model-compensated Active Disturbance Rejection Control (ADRC) as the outer loop and traditional Proportional-Integral (PI) control as the inner loop. Theoretical derivations and simulation tests were conducted in the dq coordinate system to validate the effectiveness of the approach. Simulation results demonstrate that the designed controller successfully combines the advantages of both ADRC and PI control, offering improved stability, rapid dynamic response, and excellent robustness. The proposed controller design method can be extended to grid-tie applications due to its reliable performance under various operational conditions.