PI Parameters Determination in dq Decoupling Control of VSC Terminals

Dq decoupling control is a widely used state-of-theart control method of the inner current loop in VSC-based power electronics such as STATCOM, back-to-back converter, VSCHVDC, DFIG system, etc. A key question in designing such a control system is how to select the parameters, or gains, of the PI controller in the loop, which determines the stability and timedomain performances of the system. This paper tries to sufficiently solve this problem. It starts with a theoretical insight of the popular zero-pole cancelling method, revealing a hidden problem of it. And then two new methods are proposed based on a solid control theory to overcome this problem. The studies of all methods are demonstrated on a real-grid based RTDS model. The results show that the proposed methods are sufficient to produce the PI parameters with given time-domain objectives.