Double Demodulation Type Open-Loop Synchronization Method for Single-Phase System

This paper presents a single-phase grid voltage pa-rameter estimation approach based on the double demodulation principle. The proposed solution corroborates better dynamic performance while enjoying the properties of demodulation based filtering. A notch-filter based demodulation filtering stage is proposed which rapidly rejects the DC-offset component with-out affecting the usual operating principle yielding a “double demodulation type” of pre-filtering approach. Note that the proposed method depicts an open-loop architecture and doesn't require any tuning parameter compared to well-known phase locked-loop techniques. Moreover, because of the feedback-less nature of the scheme, it requires correction in amplitude and phase information which is achieved by employing a simple mathematical regression approach. Consequently, a simple and dynamically faster synchronization scheme is achievable with the proposed solution whose performance is validated through numerous test cases.