FoM Based Optimal Frequency and Voltage Level Design for High efficiency High density Multilevel PFC with GaN Device

In space-limited applications, multilevel converters with GaN devices have shown great advantages in efficiency and power density. In the traditional design process, for a selected voltage level number, the voltage rating of devices is decided; and, the loss of each device should be calculated. Furthermore, with the selectable numbers of voltage level increasing, the complexity of design grows rapidly. In this paper, a simplified method based on device Figure-of-Merit (FoM) is proposed. Given the efficiency requirement, optimal frequency and voltage level can be easily obtained. According to the method, a 2kW prototype is built, achieving over 99% efficiency and 1400W/in3 power density.