Differential control is one of the most basic control units. However, it is limited in practical applications due to the high-frequency noise it introduces, which can reduce the quality of the grid current and even endanger the stability of the system. Nonetheless, the predictive function of differential control is invaluable in improving the dynamic performance of new energy generation systems, enhancing the quality and stability of electric energy in complex grid scenarios, and extending the control performance boundaries of power electronics devices, which has important implications for the development of control technology. Accordingly, this book focuses on the research of new methods for implementing differential control in power electronics devices and carries out application research in the fields of power control and signal processing to enhance the control performance of new energy grid systems. In this chapter, the background and significance of this research are introduced, and the current status of research on differential control technology both domestically and internationally is summarized, including grid-tied inverter control technology, grid voltage feedforward technology, active damping technology, and differential control technology. Finally, the research content and structure of this book are presented.