Disturbance Observer-based Finite-time Control for DC-DC Converter Feeding Constant Power Loads with Unknown Load Variation

The constant power load has destabilized negative characteristic. Thus, to ensure stable operation of the DC-DC converter feeding constant power loads, the excellent nonlinear controller should be employed. In this paper, the disturbance observer-based finite-time controller is proposed for the DC-DC converter feeding constant power loads with stable operation and smooth transient performance. First, the state space average model of the system is analyzed, which considers the unknown load variation. Second, the disturbance observer is designed to estimate the unknown disturbances. Moreover, the finite-time controller with disturbance compensation is constructed. The rigorous proofs indicate that not only the closed-loop system can be large-signal stable, but also the system can converge to the desired point within finite time. Finally, the effects of the proposed controller parameters on the system transient performance are observed by the simulation. The transient performance comparisons among the proposed controller, the finite-time controller without an observer, and the double-loop PI controller are taken by simulation. The results show that the proposed controller not only reduces two sensors but also realize accurate tracking and large-signal stability.