Time Delay Compensation For A DSP-Based Current-Source Converter Using Observer-Predictor Controller

The inevitable time delay of the digital controller can degrade the performance of a converter system. Further, this time delay may depend on both sampling and switching cycles of the converter. Therefore, with applications where the converter operates at low or medium switching frequency, the time delay can severely affect the system dynamics. Further, in controlling a current-source converter, this time delay can cause oscillation in the system. The paper proposes the use of an observer-predictor state feedback algorithm to compensate the time delay in a DSP based controller. Experimental result shows that the time delay in a DSP-based controller can have significant effect on the CSC performance. Simulation and experimental results also shows the proposed control approach can successfully compensate the time delay and provides fast dynamics to the CSC.