A Novel Control Strategy of an Islanded Microgrid Based on Virtual Flux Droop Control and Direct Flux Fuzzy Control

Saheb Khanabdal ,Mahdi Banejad ,Frede Blaabjerg ,Nasser Hosseinzadeh

doi:10.5829/ije.2021.34.05b.21

Saheb Khanabdal , Mahdi Banejad + Show 2 more

Open Access

https://doi.org/10.5829/ije.2021.34.05b.21

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Abstract

This paper proposes a novel control strategy of an islanded microgrid based on virtual flux droop (VFD) control. In the conventional VFD method, the direct flux control (DFC) technique is used to generate the switching signals using the hysteresis regulators and a switching look-up table. Therefore, the voltage and the current ripples are inevitable. Moreover, as a single switching vector is applied in each control period and none of the switching vectors can produce the desired voltage, the desired dynamic performance is not achieved. Here, a novel direct flux fuzzy control (DFFC) technique is proposed to choose the best switching vector based on fuzzy logic. Furthermore, only a fraction of the control period is allocated to the appropriate active switching vector which is selected by the DFFC technique whereas the rest of the time is allocated to a null vector. The duty cycle of the selected active switching vector is optimized using a simple and robust mechanism. In order to evaluate the performance of the proposed method, an islanded microgrid and the proposed control strategy is simulated in Matlab/Simulink software. The results prove that the dynamic performance response is improved and the demanded load power is proportionately shared between the sources, while the voltage and current ripples are significantly reduced

Highlights

In recent decades, distributed generation (DG) has attracted growing attention of researchers as an efficient solution for worldwide demand to reduce the reliance on fossil fuels and increase the use of renewable energy
This paper proposes a novel microgrid control strategy by using fuzzy logic control to overcome the disadvantages of the conventional virtual flux droop control
The appropriate switching vector to apply to the inverter is selected from a look-up table, which has three inputs, including the number of the section, where the virtual flux vector of the inverter is located, along with the outputs of the hysteresis regulators

Summary

Introduction

In recent decades, distributed generation (DG) has attracted growing attention of researchers as an efficient solution for worldwide demand to reduce the reliance on fossil fuels and increase the use of renewable energy. The “plug and play” feature is achieved, with the result that the expansion of such a system becomes easier which allows to replace or add one unit with no need to stop the whole system Based on this strategy, the frequency is adjusted as a function of active power and the voltage amplitude of the inverter is regulated as a Author. The proposed control strategy is robust to computational errors, disturbances, noises and parameter drifts In this group of methods, complex transformations are needed and communication with the central control unit of the microgrid is needed to send measured parameters and receive reference values which are required to generate compensatory terms.

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