Hybrid sliding mode control of DC-DC power converter circuits

This paper explores a technique to obtain a constant output DC voltage from a DC-DC power converter. The proposed control law overcomes instabilities arising in boost converters switched according to a voltage-based sliding surface. This has been achieved by combining this switching surface with a current-based one and selecting the appropriate surface in a given situation. Further the ripples in the output voltage are controlled by the principle of energy balance. Whenever the energy stored in the output capacitor goes below a threshold value, additional energy is drawn from the source and transferred to it according to requirements. This switching law has been found to work for discontinuous inductor currents.