Modeling, Digital Control, and Implementation of a Three-Phase Four-Wire Power Converter Used as a Power Redistribution Device

Abstract

This paper presents a power electronic converter used to redistribute the power among the phases in unbalanced power systems, which is supposed to be designed based on the involved degree of unbalance. A bidirectional converter is chosen for this purpose, whose modeling is presented in the dq0 system. This solution can be considered as part of a unified control system, where conventional active power filters may be solely responsible for compensating harmonics and/or the tuning of passive filters becomes easier, with consequent reduction in involved costs in a decentralized approach. The adopted control strategy is implemented in digital signal processor TMS320F2812, while experimental results obtained from an experimental prototype rated at 17.86 kVA are properly discussed considering that the converter is placed at the secondary side of a transformer supplying three distinct single-phase loads. It is effectively shown that the converter is able to balance the currents in the transformer phases, thus leading to the suppression of the neutral current.