Robust digital deadbeat control for DC-DC power converter with online parameter estimation

In this paper, a robust digital deadbeat current controller with online estimation of inductor value, is proposed for a fourth-order boost dc-dc switching power converter. A general digital deadbeat control law is derived for the inductor-1 current of the converter, which can also be extended to inductor-2 current. In-order to achieve robust performance and to reduce the sensitivity of the controller to parameter drift, the control law is updated in every switching cycle based on the online estimated value of inductor current slope and inductance. The proposed online estimation method requires only one sample in one switching cycle, thereby eliminating the need of any extra sampling, current sensing or analog to digital conversion (ADC). This reduces the time delay and phase lag associated with extra sampling. The closed-loop performance and stability of the converter is analyzed through computer simulations. Simulation results are then validated experimentally on a 28 V, 30 W laboratory prototype converter.