Direct prediction compensation strategy of unified power quality conditioner based on FCS-MPC

The finite control set model predictive control (FCS-MPC) has drawn considerable attention in the integrated control of the unified power quality conditioner (UPQC) due to the characteristics of high dynamic response, internal decoupling and multiple constraints. In this study, a new direct prediction compensation strategy (DPCS) based on FCS-MPC is proposed, which eliminates the harmonic detection algorithm, simplifies the UPQC controller structure and reduces the steady-state errors. By compensating for the time delay of FCS-MPC, the UPQC can mitigate the power quality problems more accurately and timely. The FCS-MPC value function can be with various constraints, which makes the UPQC suitable for more situations. Compared with the indirect prediction compensation strategy, the designed DPCS has better time-delay compensation effects, which can reduce the harmonic components of the user-side under transient disturbances. The simulation results show that the proposed compensation strategy can achieve better dynamic and steady-state performance on power quality problems such as voltage sags, swells, interruptions and harmonics.