Effects and analysis of minimum pulse width limitation on adaptive DC voltage control of grid converters

This paper presents an adaptive dc-link voltage controller for the purpose of decreasing the operating dc-link voltage in a back-to-back converter system. An outer loop to control the maximum modulation (Mmax) index is added to the conventional dc-link voltage controller, and hence the system can online adapt its dc-link voltage reference based on the system operating state. Furthermore, the relationship between current THD, minimum pulse width limitation and Mmax index reference is analyzed in order to obtain an optimized performance of the system. Finally, the dynamic performance and analysis of controller is investigated by experimental results.