This thesis implements and analyzes a grid support function for a smart inverter. Due to environmental and air pollution issues, the installation of distributed power using renewable energy has been increased. However, various problems arise when power converters with various output characteristics are connected to the system. Therefore, it is necessary to control the output of the inverter according to the voltage and frequency of the grid. This is called a grid support function which is mandatory to install the function in some countries. The inverter equipped with a grid support function is called the smart inverter. In order to utilize various functions, the smart inverter consists of three boards. First, the main control is a DSP board which is equipped with DSP. The main control system is required a digital processor for fast and accurate control. Also, it is necessary to share information with communication equipment. The second is a breaker control board for connection between the grid and distributed power output. Finally, a sensing board that receives various analog information including voltage and current sensors is required. The grid support function for the smart inverter is implemented and analyzed through simulation and experimental results.