Evaluation of power converters to implement bipolar DC active distribution networks — DC-DC converters

The configuration of power converters in future bipolar dc active distribution networks influences the electrical functions in such networks and their overall conversion efficiency. In this context, the dc-dc converters that are employed to balance the dc feeder voltages and/or balance its transmitted powers are key elements in such systems. This work addresses different dc-dc converter topologies that can be employed to implement bipolar dc networks. The semiconductor efforts and losses for each converter topology are evaluated and the functions that such converters are able to perform are discussed aiming to compare the devices. Furthermore, the application of two converter topologies and proper modulation schemes is proposed for the functions of voltage balancing and current redistribution.