An exploration of interchangeable data structure used in automated printed circuit boards (PCB) design for power electronics applications is presented in this paper. The key features include generation, modification and assessment needed by the automatic design and optimisation programmes are identified and discussed and the essential capabilities are defined. Existing PCB file formats from commercial software have been reviewed and the insufficiency is observed. A prototype data structure, named copper polygon areas (CPA), is illustrated and typical use case examples are shown to justify the simplicity, compatibility and effectiveness of the new design. This study also lays the foundation stone and sets the baseline benchmark for future automated trace shape optimisation algorithms in versatile power electronics applications.