Recently, various researches and developments of 48V mild hybrid system are being actively studied due to advantages in terms of cost. A 48V hybrid system with various configuration has been proposed, and some companies have proposed the system that downsizes engine by using a P0 configuration motor and electric supercharger. The P0 configuration motor and electric supercharger all support the power of an engine, but the research on how each system operates in order to improve fuel economy is still lacking. Therefore, in this paper, the operating characteristics for improving the fuel economy of each system used as the power assistant of the engine are compared. In order to compare the most optimized behavior for fuel economy, we used Dynamic Programming (DP), a global optimization technique, and Dynamic programming simulation was performed in Matlab environment.