The review paper presents a prologue of power electronics devices and its industrial applications including wide band gap semiconductor devices in range of 600V to 1700V and latest evaluation of Gallium Nitride High Electron Mobility Transistor technology (GaN HEMT) in range of 30V to 650V with applications. The study emphasizes advance power electronic applications in renewable energy system, smart grid power system, power saving, electric vehicles and energy storage system. Similarly, comparison of latest WBG semiconductors as SiC, SiC JFETs, SJ MOSFETs and GaN-HEMTs discussed in terms of different parameters e.g static losses, dynamic losses and temperature impact, thus further signify latest GaN technology evolution and its related challenges with detailed static as well as dynamic characterization. This paper demonstrates all types of electronics devices in power sector and its practical usage mentioned in detail, it includes tradeoff between different WBG devices and also explain GaN functions and applications in various circuits of high efficiency and density.