A comprehensive analysis and design of a single phase active power filter with unified constant-frequency integration control

In this paper, an analysis and design for a single-phase active power filter (APF) with unified constant-frequency integration (UCI) control method is presented. The proposed control method eliminates the need of sensing the load current, a nontrivial task of calculating the harmonics and reactive current components, as well as the use of multipliers, as reported by many previous reported control methods. In addition, the switching loss is reduced by employing unipolar operation mode. The design methodology including electromagnetic interference (EMI) filter is also discussed in detail. The theoretical analysis is verified by experiments.