High efficiency of power converters placed between alternative energy sources and the utility grid is required to maximize the utilization of these sources. Power quality is another aspect that requires large passive elements to be placed between these sources and the grid. This book, therefore, provides the different modern technologies for energy efficiency improvement and develops a higher-level high frequency power converter system (HFPCS) that optimizes the use of hybrid renewable power injected into power grid. HFPCS provides high efficiency, reduced size of passive components, higher levels of power density realization, lower harmonic distortion, higher reliability, and lower cost. Dynamic modeling for each part is developed, simulated and tested. Steady-state performance with battery storage is analyzed. Various types of algorithms are developed and tested to verify the effectiveness of the power conversion topologies. The developed HFPCS is compared experimentally with other currently available power converters. HFPCS is also employed inside a microgrid system infrastructure, connecting it to power grid to verify its power transfer capabilities and grid connectivity.