Nonlinear Differential Geometry Thoary And The Application In Control Of Asynchronous Motor

In this paper, the control system of asynchronous motor and the development of nonlinear control theory are firstly summarized in detail. And the application problem of the nonlinear systems geometry theory in asynchronous motor control was drew out with regard to the two classical problems that decoupling and linearization of the nonlinear systems differential geometry theory. Subsequently the basic conception and the basic tool of nonlinear systems differential geometry are described in detail, and some methods, conclusion and theorem of nonlinear decoupling and exact linearization are summarized. Exact linearization and decoupling of the five-order affine nonlinear model of an asynchronous motor under the d-q coordinate frame was realized by the method of nonlinear systems differential geometry theory, and the control laws are simplified further in order to make the control laws applied widely. The controllers are designed separately for the subsystems of the rotational speed and rotor flux. The state feed back linearization method of differential geometry theory is becoming superior more and more, but the math model and the parameters of the motor need to be known exactly. However we usually can't know the parameters of the model exactly, and they often change, for example the resistance of rotor changes greatly as the magnetic field saturated and the temperature of rotor resistance changed greatly. The torque of the load changes usually as well in practical application. It makes the static and dynamic performances of the motor become worse and worse. In this paper, the parameter disturb was introduced based on decoupling control of asynchronous motor. MRACS (model reference adaptive control system) method was used to realize exact estimation of the parameter disturb. We can get adaptive decoupling control laws with parameter disturb by mean of decoupling and linearization theory of nonlinear systems differential geometry when the parameters (the rotor resistance and the load torque) of the motor change greatly. Finally, the simulation experiment was given. The simulation results are presented to verify vary good static and dynamic performances with the methods in this paper, and the high quality control of the asynchronous motor was realized.