Abstract
Signal processing based on frequency polarity has been attracting wide attentions due to its potential industrial-applications. It is popular to employ two vector-rotators for such signal processing. But, It was very recently reported that equivalent signal processing effect can be attained in a much simpler manner using two-input two-output filters in the D-module. This paper further investigates a class of characteristic-varying systems in the D-module, which contains the filters in the D-module as a special case, and gives new analytical results on their properties from viewpoints of existence, realization and stability. If the results are applied to filter problems, n-th order D-module filters in new forms can be easily and directly obtained, whose stability and response equivalent to the associated filters with vector-rotators are guaranteed. If the results are applied to AC motor modeling problems, dynamic models and block diagrams of AC motors in general reference frame are easily and directly obtained. Very general and useful analyses are given for newly proposed a class of characteristic-varying systems in the D-module that have potential usefulness in various industrial applications including control of magnetic bearing system, analyses and active compensations of power systems, and sensorless drives of AC motors.
