Operation Principles and Control Strategies of Cascaded H-bridge Multilevel Active Power Filter

The operation principles and control strategies of the cascaded H-bridge multilevel APF are reported. The phase shift cascaded pulse-width modulation (PSCPWM) is adopted to generate gating signals for each H-bridge module. A novel voltage balancing control of dc-link capacitors is proposed. The reference tracking is realized by the proportional and resonant controller in the current loop. The validity of the proposed control scheme is validated by the simulation results under both homogenous and non-homogenous H-bridge module scenarios. Ill. 12, bibl. 5 (in English; summaries in English, Russian and Lithuanian).