Three-phase active power filter based on the four states commutation cell DC-AC converter. Design and implementation

This work approaches the subject of Active Power Filtering for the cases where the current stress of the semiconductor devices is a point of major concern. Instead of the classic parallelism of inverters, a topology with coupled inductors is proposed to address this problem. In addition this topology provides advantages from the point of view of the output current ripple, providing more flexibility on the design of the filter inductors. A more simple and cost-effective control strategy based on the sensing of the AC source currents is implemented using the Park transformation. Simulation and practical experiments are presented in order to prove the correct behavior of the system. The experimental set-up consists on a non-linear load rated for 8 kVA connected to a 380 V (line-to-line) AC grid, trough an isolation transformer. A Four States Commutation Cell, DC-AC Converter is connected as a shunt Active Power Filter with a DC link voltage of 600 V. The control algorithm is programmed on a DSP board TMS320F28335 from Texas Instruments.