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.

I. Introduction

The integration of the DG with the utility distribution network offers a number of technical, environmental and economic benefits. It also gives a great opportunity for distribution utilities to improve the performance of networks by reducing its losses [1]. The technical challenges associated with the DG can be classified into different categories.