Synchronous reference frame hysteresis current control for grid converter applications

This paper presents the application of space-vector based hysteresis current control in the synchronous reference frame for grid connected voltage source converters. The space-vector based approach allows for systematic application of zero-voltage vectors and prevents high switching frequencies caused by phase interaction. The average switching frequency can be minimized by always selecting the zero-voltage vector that is closest to the previous switching state. For operation in a grid connected converter with LCL-filter, the current references to the hysteresis controllers are given by a DC-link voltage controller and an Active Damping strategy for preventing filter oscillations. Results from simulations and laboratory experiments are presented to discuss the features of the investigated approach compared to traditional phase-current hysteresis controllers.