An Improved Internal Model Principle Based Multivariable Nonlinear Control Method with Multiclass Nonharmonic Disturbances and Its Application to Speed Control of a Motor Drive System

Yang Yu,Yikun Xu,Zengqiang Mi,Tong Zhao

doi:10.1155/2014/570542

Abstract

We study the global disturbance rejection problem for a class of general multivariable nonlinear systems with multiclass nonharmonic disturbances. The paper first introduces the importance and state of the art for disturbance rejection problem and describes the control problem in the form of mathematical expressions. It stresses the multiclass disturbances produced by the exosystem satisfying certain characteristic conditions. Then, the nonlinear internal models are designed in accordance with different characteristics of multiclass external disturbances. On the basis of introduction of the control law for disturbance-free system, a multivariable state feedback controller is devised in terms of the designed internal model equations and corresponding assumptions. A Lyapunov function is constructed to theoretically prove the global uniform boundness of all signals for the multivariable closed-loop system. Finally, the presented method is applied to implement the speed control and reject the multiclass nonharmonic disturbances for a two-input motor drive system. The simulation results testify correctness and effectiveness of the presented algorithm.

Highlights

Due to its importance, the problem of disturbance rejection generated by the exosystem has been paid great attention in the world over the past few decades [1–3]
The major conclusions of the research are summarized as follows: (1) in light of the multiclass nonharmonic disturbances, a class of new multiclass nonlinear internal models can be constructed on the basis of the definitions of expanded steady state generator and internal model principle (IMP), and id(x1) (A)
The characteristics of which depend on the structural information of exosystem and state information of closed-loop system; (2) a multivariable nonlinear state feedback controller associated with the designed internal model equations is designed; the application of Lyapunov theory can justify the convergence of the proposed control algorithm; (3) the application of the algorithm into a two-input variable motor drive system demonstrates that the presented algorithm is able to suppress the multiclass disturbances and guarantee the multivariable closedloop system global uniform convergence

Summary

Introduction

The problem of disturbance rejection generated by the exosystem has been paid great attention in the world over the past few decades [1–3]. This problem in nonlinear system has been concerned in a recent period of time [4–6]. Many industrial applications, such as servo system, wind power system, photovoltaic system, and other modern systems, which rely on power electronic equipments to work, [7–9], are frequently influenced by the external disturbances generated by exosystem [10, 11]. Rejection of external disturbances by means of new ways [14, 15] is an important work to improve the working performance of these industrial systems. From the state-of-the-art technologies in disturbance rejection, the researchers frequently assume the following:

Objectives

Methods

Conclusion