AN IMPROVED MODEL-FREE ADAPTIVE CONTROL ALGORITHM FOR VSC-HVDC POWER TRANSMISSION SYSTEMS

Abstract

ABSTRACT: Improving the efficiency and operation of power transmission is important in power system due to the continual increase in demand for electric power. In addition, many remote areas throughout the world lack sufficient access to electricity. The voltage-source converter based high voltage direct current (VSC-HVDC) power transmission system can satisfy those demands. How to manage the active power of the converter station in the VSC-HVDC system is a challenge issue. In this paper, an improved model-free adaptive control (iMFAC) algorithm is proposed to overcome this issue. Considering VSC-HVDC as a kind of nonlinear system with unknown structure, an online dynamical linearization using the data-driven strategy is presented to build the model. Then, the control law of iMFAC is obtained by calculating a cost function. Furthermore, parameters of iMFAC are auto-tuned online using the measured input/output data. The mathematical analysis proofs the existence of solution. The experiment on the Flexible-HVDC system with five terminals also demonstrates the effectiveness of the proposed algorithm. Keywords: iMFAC, VSC-HVDC, Active power regulation, Converter station