Sliding mode control of a high voltage DC-DC buck converter

In this paper, a sliding mode approach is used in order to design a high voltage two-cell DC-DC buck converter. The studied system is derived from the elementary DC-DC buck converter where the single switch is substituted by two ones connected between them through a capacitor. One of the control objectives is to get a good voltage sharing between the two switches while the other is to maintain the output voltage to a desired value. Steady state analysis, dynamic behavior and control design of the system are presented. After identifying the switching surfaces, a linear model is derived and a sliding mode control for the system is designed in order to maintain a regulated output voltage and at the same time to share the high input voltage between the two switches. Numerical simulations show that the system presents a good response in front of line and load variations.