Yukai Shang

Constant power loads have negative impedance characteristics, which reduce the damping of DC/DC converter systems and have negative effects on the stability of the DC microgrid. In this paper, a finite-time parameter observer-based sliding mode controller is proposed for a boost converter with constant power loads. Firstly, a non-singular terminal sliding-mode controller is designed based on the flatness of the differential and sliding mode control theory. Secondly, a finite-time observer is designed to estimate the input voltage and tunes the parameter of the controller in time. Thirdly, the finite-time stability of the closed-loop system is proved through the proposed controller. Finally, the effectiveness and robustness of the proposed controller with unknown input voltage are verified by simulation. The proposed controller can guarantee finite-time convergence without input voltage sensors, which can reduce system cost and improve system reliability.

The full-information state feedback controller is usually used for regulating the output voltage of converters. Sufficient sensors should be adopted to measure all of the states. However, the extensive use of current sensors not only increases the cost of the overall system, but also affects the reliability. In this paper, the sensorless control problem of DC–DC boost converters is addressed to avoid the need for the current sensor. First, a PI passivity-based control (PI-PBC) is proposed to stabilize this converter. The main feature of this design is that the exponential convergence of the system is guaranteed. Afterward, a generalized parameter estimation-based observer (GPEBO) is presented to estimate the inductor current with the finite-time convergence (FTC). By adding this estimate in the above PI-PBC, a sensorless controller is developed. Thanks to this FTC, the exponential convergence of an overall closed-loop system is ensured. Finally, the simulation and experimental results are given to assess the performance of the proposed controller.