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Dual Sequence Controller with Delayed Signal Cancellation in the Rotating Reference Frame | IEEE Conference Publication | IEEE Xplore

Dual Sequence Controller with Delayed Signal Cancellation in the Rotating Reference Frame


Abstract:

Dual-sequence current controllers of voltage source converters (VSCs) feature two separate rotating reference frames (RRFs), commonly named dq frames, and rely on techniq...Show More

Abstract:

Dual-sequence current controllers of voltage source converters (VSCs) feature two separate rotating reference frames (RRFs), commonly named dq frames, and rely on techniques that isolate the positive and negative sequences of three-phase measurements. One of these techniques is the delayed signal cancellation (DSC). It is performed in the stationary reference frame (SRF), also known as αβ frame. The DSC combines old values of one axis with new values of the other axis of the SRF. The results are, then, transformed into the RRFs for use in the current controller. This filtering process introduces an extra layer of complexity for dual-sequence current controllers, which could otherwise operate solely in the RRFs. This paper introduces a frequency adaptive DSC method that operates directly in the RRF. Moreover, an averaging of two of the proposed DSC filters with contiguous integer delays is employed for reducing discretization errors caused by grid frequency excursions. A formal proof of the equivalence between the αβ and dq DSC methods is presented. Furthermore, computer simulations of a case study support the interpretation of the results.
Date of Conference: 02-05 November 2021
Date Added to IEEE Xplore: 23 December 2021
ISBN Information:
Print on Demand(PoD) ISSN: 1093-5142
Conference Location: Cartagena, Colombia

I. Introduction

The traditional control in the rotating reference frame (RRF) (dq) of three-phase voltage source converters (VSCs) assumes that grid voltages are reasonably balanced. However, unbalances appear frequently in practical applications of grid-connected power electronic converters. When the grid voltage is not balanced, a second harmonic component appears in the instantaneous active power and hence dc-link voltage of the converter [1]. This degrades the performance and stability of the VSC. The performance of a VSC operating under unbalanced, reduced voltage, or fault conditions can be improved by dual-sequence current controllers [2]–[5].

References

References is not available for this document.