Multirate sampling based HVDC converter model and its self-tuning control

A discussion is presented of the development of multirate-sampling-based self-tuning controllers for HVDC (high-voltage direct-current) converter current control. A suitable linearized multirate-sampling-based converter model that takes into account the appropriate discrete converter behavior is derived. This converter model is used for self-tuning controller design. Two different self-tuning controllers are developed which can also be used for servo tracking. The nature of a converter firing system necessitates the development of two-step-ahead prediction of the DC current so that the appropriate corrective action can be taken in advance. The proposed controllers were validated through extensive digital computer simulation