A twelve-switch power conditioner for voltage and current compensation in three-phase four-wire grids

An interesting solution for problems associated with system voltage, such as sags and swells, as well as those associated with current such as low power factor and harmonic distortion is the unified power quality conditioner. However, one of its drawbacks is the high number of semiconductor devices since its conventional topology presents two full-bridge converters connected in a back-to-back configuration. Therefore, this paper proposes a twelve-switch converter topology as a power conditioner for voltage and current compensation in three-phase four-wire grids. The developed topology ally low voltage characteristic of dc bus of a hybrid power filter with a reduced number of semiconductor switches and the capability of homopolar voltage and current compensation through the converter fourth leg for the neutral wire connection. In the twelve-switch converter, there are two sets of three-phase four-wire outputs, each set behaving as an independent converter unit. One of these units is connected in parallel to the load by means of a series LC filter, working as a hybrid power filter and being responsible for the compensation of current harmonics and imbalance. The second converter unit is responsible for compensating harmonics, sags or swells in the grid voltage, in such way that the load receives a sinusoidal voltage waveform. Both converters are controlled in stationary reference frame through proportional-resonant controllers. Experimental results demonstrate the validity and the effectiveness of the proposed topology.

Automated summary

This paper proposes a twelve-switch converter topology as a power conditioner for voltage and current compensation in three-phase four-wire grids. The developed topology combines the low voltage characteristic of a hybrid power filter with a reduced number of semiconductor switches and the capability of homopolar voltage and current compensation. Experimental results demonstrate the validity and effectiveness of the proposed topology.