Non-singular terminal sliding mode control of DC-DC buck converter with fixed frequency

In order to solve the problems such as lower control performances and unfixed switching frequency in the traditional sliding mode control (SMC) of DC-DC buck converter, a novel modulation method with constant switching frequency is proposed on the basis of non-singular terminal sliding mode (NTSM) and duty cycle control. The averaging state model is established and the duty cycle is controlled to produce the periodic triggering pulses. A NTSM controller is designed and the unified stability condition of buck converter for the both cases of switching ON and OFF is also deduced. Simulation results validate the proposed method.