Active disturbance rejection controller design for harmonic suppression in MPC optimal control based on harmonic state space modeling

This paper proposes a harmonic suppression strategy for photovoltaic-voltage source converters (PV-VSC). The proposed method utilizes a harmonic state space (HSS) model-combine model predictive control (MPC) algorithm, which provides a comprehensive representation of the global characteristics of AC/DC harmonic coupling impedance in photovoltaic systems. The HSS-based converter model operates as a linear time-varying periodic system, which allows for the implementation of MPC to optimize the HSS equation. This optimization yields voltage increments across various harmonic orders, providing feedforward compensation for the current controller. By incorporating feedback signals into the current control, harmonic compensation is achieved, resulting in improved power quality. Furthermore, a decoupled proportional resonance-linear adaptive disturbance rejection control (PR-LADRC) is employed to effectively mitigate steady-state errors and decrease total harmonic distortion in the presence of DC-side disturbances. This is accomplished by decoupling the disturbance observer from the controller and integrating the increment feedback signal derived from the MPC-HSS. Finally, the efficacy of the proposed method and the analysis results are corroborated through numerical simulations.