This book is devoted to the optimum design of the DCT in a hybrid AC/DC microgrid, which takes into account not only the influence of different inductors/capacitors values, but also numerous design goals (i.e., VCG, efficiency, stability and so on). This book examines the DCT's design problem in detail. It begins by reviewing existing DCTs in, the hybrid AC/DC microgrid and their design problems. Following that, this book proposes a family of DCT optimization design approaches to ensure that the designed DCT has good power transmission and voltage regulation ability in the hybrid AC/DC microgrid, even when the actual inductors/capacitors values fluctuate with practical power and temperature. Following that, this book provides a family of multi-objective optimization design methodologies for the DCT to guarantee that it concurrently achieves the requirements of VCG, efficiency, and system stability. This book also covers how to control the DCT in a hybrid AC/DC microgrid optimally and generically.