Showing papers by "Kang-Zhi Liu published in 2010"

LPV Modelling and Gain-Scheduled Control Approach for the Transient Stabilization of Power Systems

Abstract: In this paper, a new control approach is proposed for the transient stabilization of a single-machine infinite-bus power system. The proposed method is based on linear parameter varying (LPV) modeling of the nonlinear power system and the design of a gain-scheduled output feedback controller. It is well-known that when large disturbances or a fault occurs, the nonlinearity inherent in power systems can no longer be ignored. The proposed method can handle the nonlinear model directly. First, we show that the nonlinear model can be transformed equivalently into an LPV system with the rotor angle as the scheduling parameter. Then, a gain-scheduled output feedback controller is designed based on robust pole placement and L2-gain minimization. Simulation results verify that the proposed method is better than well-tuned conventional power system stabilizer (PSS) control. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

High performance algorithms for the control and load identification of boost DC-DC converters

Abstract: This paper proposes two high performance control methods and an on-line load identification algorithm for boost DC-DC converters. The first is a short-horizon model predictive control method whose solution can be computed analytically, thus rendering an algorithm that can be implemented on-line. Further, we show how to find a suitable performance index so as to achieve good response. The idea is to use the inductance current as the penalized output, instead of the output voltage. The second is a 3-level hysteresis control method which is a natural extension of the conventional hysteresis control method and has three layers in the hysteresis band. The key is to set the duty ratio in the central layer as the steady-state duty ratio. Compared with the well-known PID-PWM method, the proposed methods are able to achieve a better trade-off between rise-time and overshoot in the response of output voltage. Finally, a simple on-line identification algorithm is proposed for the load resistance. Combination of the proposed control methods and identification algorithm yields high performance robust control for boost converters.

A New Model Predictive Control Approach to DC-DC Converter Based on Combinatory Optimization

Abstract: DC-DC converters by nature present hybrid behavior, which is described by a set of discrete modes associated with continuous dynamics. The control objective is accomplished by switching among the d...