Multifunction current controller for inverter-based distributed generation using combined pi-sliding mode controller via Sigma-Delta Modulation

The fast changes in the reactive power consumption can cause considerable variations at the load-side and can influence on the operation of other power consumers which and Point of Common Coupling (PCC) voltage. In this paper, a current control strategy based on Sigma Delta Modulation (ΣΔM) is presented for the interfacing DG inverter. The inverter is called Sigma-Delta based Current Controlled Voltage Source Inverter (ΣΔ_CC_VSI). It controls active and reactive powers independently with fast voltage regulation. It is shown that the ΣΔM generates sliding mode regime. As a result, it is possible to combine the Proportional-Integral (PI) with sliding mode controllers. It is shown that the proposed ΣΔ_CC_VSI reduces the harmonics amplitude variations of the unfiltered voltage. Therefore, it reduces the ElectroMagnetic Interference (EMI) problems.