Abstract

               Dynamic response is the output overshoot or undershoot that occurs when converter output load or supply voltage is suddenly varied. Dynamic response is very important in applications where converter supplying power to the load, due to the large and sudden changes in load. Three Level Buck converter topology that is preferred for point of load applications such as laptops, cellular phones, microprocessors etc. This paper presents a constant frequency hysteretic PWM controller for three level buck converter for improving dynamic response. In order to verify the effectiveness of the controller a simulation model and hardware prototype are developed. The output voltage recovery time, output voltage undershoot and overshoot during load step change and input voltage step change are verified. Simulation and experimental results show a significant improvement in the dynamic response of the three level buck converter with constant frequency hysteretic PWM controller. The hysteretic controller takes advantages of both faster dynamic response performance and simpler control structure.

Keywords – dynamic response, hysteretic controller, three level buck converter, PSIM