Hybrid current control technique applied to grid connected inverters

Voltage source inverters (VSI) with LCL filter play an important role in grid connected applications. Features such as bidirectional power flow, reduced filter volume and good electromagnetic compatibility performance make this a suitable solution for such applications. However, the current control strategy becomes more complex if compared to VSIs with simple inductive filters. Among various current controllers, the proportional+resonant (P+R) and deadbeat predictive ones present interesting characteristics for steady-state and transient performance, respectively. This paper evaluates a hybrid current control technique, based on P+R and deadbeat controllers operating together, in order to achieve a good dynamic response and reduced steady state error and, thus, benefit from the merits of each of the individual controllers.