Analysis and Synthesis of Automatic Control Systems with Controlled Converters

Abstract

Summary Controlled converters represent power amplifiers, in which any given value of the input signal xe corresponds to a characteristic course of voltage forming part of a highpower voltage system S. The output signal ya of the controlled converter normally consists of different voltage courses, while the change from one voltage course to another is enabled by S. These converters have high power gain and need only simple construction and arrangement of devices. For electrical drive sytems, to give an example, they are of great importance. The exact mathematical treatment of control loops, incorporating these controlled converters, will entail non-linear differenceequations, which up to now cannot be solved en bloc. Because of this difficulty, it was possible so far to obtain results from equations in which the non-linear system had been linearized [1]. As opposed to previous discussions we now attempt to develop a new method for the mathematical treatment of large-signal behaviour, in order to demonstrate dynamic characteristics, which up to now were unknown. To confirm the results a new sampled-data model is developed for continuous (id ≷ 0) and discontinuous (id ⋛ O) current in the controlled converter. It is apparent from these results, that only an adaptive controller enables optimum time response. The adequate investigations are exemplified and practical results are given.