Power electronic converters are indispensable building blocks of microgrids. They are the enabling technology for many applications of microgrids, e.g., renewable energy integration, transportation electrification, energy storage, and power supplies for computing. In this chapter, the requirements, functions, and operation of power electronic converters are introduced. Then, different topologies of the converters used in microgrids are discussed, including DC/DC converters, single-phase DC/AC converters, three-phase three-wire, and four-wire DC/AC converters. The remaining parts of this chapter focus on how to optimally design and control these converters with the emerging wide-bandgap semiconductors. Correlated tradeoffs of converter efficiency, power density, and cost are analyzed using Artificial Neural Networks to find the optimal design of the converters.