CHB Converter DC Voltage Control Based on Feedback Linearization

In this paper the Feedback Linearization (FL) control theory is applied to a grid-connected Cascaded H-Bridge (CHB) converter. A DC voltage control is designed taking into account the nonlinear model of the converter and its performances are compared with the performances obtained in case of a conventional PI controller. With the aim to provide a fair comparison, the results are evaluated in terms of: settling time in case of a reference voltage variation, voltage overshoot in case of a load variation and total harmonic distortion of the grid current. Simulation and experimental results demonstrate that the FL-based control provides higher power quality and faster response to reference variations than the PI control. Comparing the performances in terms of responses to the load variations, better dynamics performance can be achieved also with the FL-based control increasing the settling time while maintaining an admissible grid current total harmonic distortion index.