Nonlinear torque control of electric motor drives: Part II

In this paper, a piecewise linearization of non-linear magnetic characteristics for a drive is proposed to generalize an earlier proposed control algorithm [1] to the case with the saturation. A piecewise linearization with respect to current is crucial for extending the Floquet theory based variable transformations to this case. However, any smooth function in rotor angle 8 can be used to approximate the flux linkage characteristics. The details of a nonlinear voltage control which produce a desired torque are given in the paper. The main result can be used as a method of generalizing the Floquet theory based variable transformations for any drive, when the saturation has to be included. In this sense, the method could be used as a rigorous method of extending the vector control techniques to the case with the saturation.