The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 07, 2015
Filed:
Nov. 08, 2012
Delta Electronics (Shanghai) Co., Ltd., Shanghai, CN;
Hai-Fen Xue, Shanghai, CN;
Ai-Bin Qiu, Shanghai, CN;
Fei Lu, Shanghai, CN;
Jian-Fei Zheng, Shanghai, CN;
Abstract
A phase locking system for a three-phase alternating current (AC) electric grid and a method thereof are disclosed. The method includes: receiving a three-phase voltage of the AC electric grid and converting the three-phase voltage to a two-phase voltage signal, each of which including a positive and a negative sequence components; obtaining a pure positive sequence component by subtracting the negative sequence component from the voltage signal of each phase and using αβ/dq coordinate transformation and low-pass filtering, and phase locking the pure positive sequence component; and obtaining an error signal by subtracting a disturbance variable and subsequently subtracting the positive sequence component from the voltage signal of each phase, wherein the disturbance variable includes the negative sequence component, and obtaining a signal including the negative sequence component by performing a α-β/d-q coordinate transformation on the error signal and adjusting the error signal through a regulator.