Optimal tuning of multifunction current controller for Sigma Delta Modulation inverter-based distributed generation using PSO method

There are many consumers and equipments in Distributed Generation (DG) systems and distributed networks which have rapid changes in the reactive power consumption. These changes can result in large variations in the load-side voltage that may affect the operation of other power consumers which are fed from Point of Common Coupling (PCC). In this paper a current control strategy for inverters, based on Sigma Delta Modulation (SDM), interfacing with DG systems is proposed. The proposed interface is called Sigma-Delta based Current Controlled Voltage Source Inverter (ΣΔ_CC_VSI). Due to existing number of proportional integral (PI) controller, a particle-swarm optimization (PSO) method has been employed for best tuning the controllers. The proposed ΣΔ_CC_VSI reduces the harmonics contents of the unfiltered voltage. So it is effective in reducing the ElectroMagnetic Interference (EMI) which is important for some consumers.

I. Introduction

DG system is defined as an electric power source that is directly connected to the distribution network or into the meter on the customer-side. The integration of the DG into 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. The technical challenges associated with the DG can be subdivided into three categories [1]: •

The system interface with the grid.

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Operation and control of the DG.

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Planning and design.