Стійкість систем векторного керування напругою асинхронного генератора

Abstract

The paper presents an analysis of the stability properties of typical structures of induction generators-based vector control systems with linear proportional-integral currents and DC-link voltage controllers. The study is based on the mathematical model of an induction machine taking into account the magnetization curve. It provides the modification of the typical voltage-flux vector control algorithm by considering the saturation of the magnetic system. The stability proof problem of an induction generator-based generation system is that its model is nonlinear and nonminimal-phase, and that the dynamics of the DC-link voltage is nonlinear even for a constant flux linkage and speed due to the presence of nonlinear components which are proportional to active losses. The conditions which provide consideration of the reduced-order system dynamics are formulated and properties of local asymptotic stability of the generation system with typical vector control algorithms are proven based on the singular perturbation theory. It is shown that the local asymptotic stability is ensured when the regulation processes of the DC-link voltage and the torque-forming stator current component are decoupled, which is achieved due to the proposed special adjustment of the voltage and current controllers. A modified vector control algorithm of induction generator is studied in simulation and experimentally. At the first stage, the system dynamics is investigated when the flux subsystem is in equilibrium point. As a result, the possibility of the reduced-order system consideration for the design and analysis of the voltage regulation subsystem was confirmed. At the second stage, the dynamic behavior of the voltage control loop for different settings of the controllers was experimentally investigated. It is shown that the configuration of the voltage control algorithm proposed in the work provides the timescale separation of the current and DC-link voltage regulation processes, as well as their quasi-decoupling.