Emergency Conditions in a Three-Phase Regenerative Converter with Single-Pole Compensation with In-Band Gain Limiting

This paper presents the study of dynamic behavior of a three-phase regenerative converter with single-pole compensation with in-band gain limiting. The main purpose of the study was to locate emergency conditions in the converter. Dynamic modes map and 3D diagrams of the converter integral characteristics in the space of such system parameters, as the DC link current and the proportional gain factor of the feedback compensator, have been demonstrated. It has been shown that in the considered range of system parameters the converter is characterized by presence of a great number of stable 1-cycles with different symbolic characteristics, and the transition between them is carried out through border-collision bifurcations of a change of the solution type. On the dynamic modes map, emergency conditions are observed in the range of large values of the DC link current. The peculiarities of the dynamic modes, that are characteristic for the regenerative converter, are shown in the paper. The authors have presented the technique for localization of the borders of the desired mode and emergency modes, based on the analysis of the converter integral characteristics: power factor, distortion factor of the mains supply input current waveform and cosine of the phase angle between the input voltage and the fundamental harmonic of the mains supply input current. Detection of emergency conditions at the stage of design engineering of the regenerative converter will make it possible to choose proper values of the compensator parameters and to guarantee its reliable operation. The results of the study are of great practical importance.