Improving power factor correction by changing sliding surface of SM controller

Isolated single-stage, single-switch power factor correction have some advantages, such as fewer element count, higher efficiency, and lower oscillation output. Usually, linear controllers with limited bandwidth frequency are used for these types of converters. This controller degrades the converters performance after any sudden load change. The time required by the controller to respond to such a change is at least 2 cycles of input voltage, which cause defects such as intensive output the bulk capacitor voltage deviation. Conventional solution requires a large and costly capacitor. This paper proposes a 3 dimensional sliding surface (instead of sliding line), to improve the converter´s performance during sudden load changes. The proposed method controls the switching frequency by adjusting bandwidth hysteresis modulation. Finally, the performance improvement of the method is verified by simulation.