Predictive Direct Power Control of Doubly Fed Induction Generators to Reduce the Power Ripple During the Grid Synchronization

Ghazaleh Sarfi,Mohsen Kalantar

doi:10.11648/j.epes.20200906.11

Abstract

This paper presents a new method of predicting power based on predictive direct power control. This method reduces power ripple in a doubly fed induction generator, which makes it possible to have a smoother synchronization with the grid in low constant frequency switching. To achieve fast and smooth grid synchronization without any over current, the difference between the measure, frequency, and the phase of the stator voltage and the grid voltage should be minimized. This condition can be achieved by minimizing the error between active and reactive virtual power and their references. By predicting the virtual active and reactive power behavior and choosing different active voltage vectors and using each of them at different times among each period time, the best switching of the rotor side converter in doubly fed induction generator to have a smoother condition can be chosen. In this paper, a 15kw generator is simulated by the classic method which is direct power control, and this new method, predictive direct power control, and it will be shown how much the new method reduces the power ripple to have a smoother synchronization that doesn’t cause mechanical or electrical pressure for none of the grid and the doubly fed induction generator.

Highlights

In recent years, using renewable energies inside distribution power networks such as smart-grids [1] and microgrids [2] has been developing
The most famous one is vector control (VC) with the d-axis oriented along with the rotor flux which is the conventional method for controlling the Doubly fed induction generator (DFIG)
By controlling the two components of the current independently, a decoupled control with linear controllers such as PIs is obtained [4] & [5]. This method needs a large amount of computing compared with direct control, which can be direct power control (DPC) or direct torque control (DTC)

Summary

Introduction

In recent years, using renewable energies inside distribution power networks such as smart-grids [1] and microgrids [2] has been developing. The DFIG has several advantages such as maximum power gain in 25%-30% of the generator rating and decoupled active and reactive power control [2]. This condition is prepared by a 2-side converter which is located between the rotor of DFIG and the grid. By controlling the two components of the current independently, a decoupled control with linear controllers such as PIs is obtained [4] & [5] This method needs a large amount of computing compared with direct control, which can be direct power control (DPC) or direct torque control (DTC). In the direct control method, hysteresis comparators are used instead of PI regulators which are used in vector control, and this is another advantage for direct

Methods

Results

Conclusion