Two-step predictive control of delta-connected CHB-based parallel active power filter

Abstract

This paper presents a novel control strategy for a shunt active power filter (SAPF) based on a delta-connected cascaded H-bridge (CHB) topology, aimed at addressing two major challenges: high computational demands of model predictive control (MPC) in multilevel converter systems and the need for reliable compensation of current harmonics and reactive power under dynamic grid conditions. The proposed solution combines a computationally efficient two-step finite control set MPC with a modified instantaneous active–reactive power theory. This approach eliminates the need for weighting factors and enables implementation on low-cost digital signal microcontrollers. The effectiveness of the method is validated experimentally using a 60 kW laboratory prototype with a 200 MHz microcontroller. Results confirm fast dynamic response and significant harmonic reduction.