PROJECT TITLE :

MIMO-Identification Techniques for Rapid Impedance-based Stability Assessment of Three Phase Systems in DQ Domain - 2017

ABSTRACT:

Grid impedance and the output impedance of grid-connected inverter are important parameters for the operation of grid-connected systems, such as solar, wind, and other distributed-generation resource systems. The impedance mismatch between the grid and the interfacing circuit usually generates harmonic resonances that lead to reduced power quality and even instability. Since the impedances sometimes vary over time as a perform of the many parameters, on-line measurements are required for stability assessment and adaptive control of the inverters. Many strategies are proposed for fast, correct measurements of impedances, but the use of multiple-input multiple-output (MIMO) identification techniques have not been thought-about. Applying the MIMO techniques, totally different elements of the inverter output impedance or grid impedance will be simultaneously measured during one measurement cycle. Therefore, the operating conditions of the system will be kept constant throughout the measurements, and the general measurement time is considerably reduced. This paper shows the use of orthogonal binary sequences to simultaneously live the “d” and “q” parts of grid-connected inverter output impedance and/or grid impedance. Experimental results primarily based on a 3-section grid-connected inverter are presented and used to demonstrate the effectiveness of the proposed methods.