Dual polarity multi-level boost DC-DC converter

With the shift in focus to DC collection networks, for renewable applications, comes the opportunity to explore the potential of DC links for bipolar DC collection networks. These networks provide greater transmission efficiency compared to their AC counterpart and do not require frequency or phase matching techniques. While DC links for unipolar networks have been realised within the literature, there has been limited focus on DC links that are compatible with bipolar networks. With their inherent cable redundancy, bipolar collection networks are an attractive option for renewable applications where cables are difficult to access. A demonstration unit of a scalable bipolar DC-DC converter is presented and experimentally validated. The unit utilised the combination of 2N-1 and inverting 2N Cockcroft Walton topologies in tandem, as this design facilitates a simultaneous positive and negative output, that operates with a single switch. The similar designs of the 2N-1 and 2N topologies enable balanced voltage output, minimising the need for voltage-balancing techniques. The efficiency of the demonstration unit was shown to be 98 % during steady-state operation.