Nested integral sliding modes of large scale power system.

Abstract

A sliding mode decentralized excitation controller for multimachine power systems is designed to stabilize the power angle and regulate the terminal generators voltages. First, the block control approach is used to derive a nonlinear sliding manifold, on which the mechanical dynamics are linearized. Then, a combination of the integral and nested sliding mode techniques is applied to reject both the matched and unmatched perturbations. The designed controller was tested through simulation of WSCC (Western System Coordinating Council) under small and large perturbations. The presented simulations confirm effectiveness of the proposed controller.

Exact compensation of unmatched perturbation via quasi-continuous HOSM

“…A high gain approach is used to achieve compensation of the unmatched uncertainty and stabilization of the sliding mode dynamics. In [13] a sliding mode controller is designed using the combination of: block control [14], a sigmoid approximation to the integral sliding mode control [15], and nested sliding mode control [16]. The approximation to the integral sliding mode control combined with nested control technique is used to suppress perturbations.…”

Integral HOSM Semiglobal Controller for Finite-Time Exact Compensation of Unmatched Perturbations

“…This transformation requires smoothness of each virtual control, that is why sigmoid, instead of signum functions are used. With the use of the high gain approach in [1] and sigmoid functions in [15], [18] they prove that asymptotic tracking is achieved.…”

“…• Now for the state x n01 , with n01 defined according to (15) The function f n01 , may not be compensated right from t = t 0 because of the arbitrary initial condition of xn. However due to the BIBS condition xn01 remains bounded and after t = t0 + Tn, when x n = n01 _ 6 n01 = u n01;1 + !…”

“…A high gain approach is used to achieve compensation of unmatched uncertainties and stabilization of the sliding mode dynamics. In [15] a sliding mode controller is designed using the combination of block control [16], a sigmoid aproximation to the integral sliding mode control [17] and nested sliding mode control [18] coordinate transformation is applied to design a nonlinear sliding manifold. This transformation requires smoothness of each virtual control, that is why sigmoid, instead of signum functions are used.…”

Robust multimachine power systems control via high order sliding modes

“…In [27,28], classical SM controllers were presented for single machine infinite-bus systems, and in [29], a decentralized classical SM robust control scheme was designed for multimachine power system, based on the eighth order model for each generator in the EPS. The classical SM controllers presented in [30,31] are an extension of [29], considering again the generator eighth order model. However, in the above works, the exciter dynamics were not considered.…”