# Improved Control of Grid-connected DFIG-based Wind Turbine using Proportional-Resonant Regulators during Unbalanced Grid

^{1}

^{2}

^{3}

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## Abstract

**:**

## 1. Introduction

_{2}emission [1]. Such a problematic requires new alternative technologies to create energy in environment-friendly ways and, considering the increasing demand for global energy, society has a greater environmental responsibility to develop green technologies. Under the electrical power market expansion, the most rapidly developed sector is wind energy [2].

## 2. DFIG Control

_{s}and I

_{r}are the stator and the rotor currents, respectively. Additionally, according to Figure 2, the stator and the rotor voltage can be written as:

#### 2.1. DFIG Control Strategy

_{m,MPPT}by the following equation:

#### 2.2. Grid-Side Converter Regulation Using PR regulators

## 3. Grid Code (Output Current Limitation)

## 4. Digital Real-Time Simulation of the RSC

_{DC}= 800 V) is simulated with the MATLAB/Simulink environment, and secondly, the dSPACE blocks are added to the system in order to run in the digital real-time simulator. The generator parameters are given in Table 1.

## 5. Controller Hardware-in-the-Loop Simulation for the Grid-Side Converter

## 6. Conclusions

## Author Contributions

## Funding

## Conflicts of Interest

## References

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**Figure 8.**(

**a**) LVRT requirements according to IEC 61400-21 and (

**b**) Spanish grid code requirements for the reactive power [49].

**Figure 10.**DRTS of the RSC control for wind speed (

**a**), rotor speed (

**b**), rotor current (

**c**), and electromagnetic torque (

**d**).

**Figure 12.**Simulation results of the proposed LVRT strategy for a symmetrical voltage sag of 0.1 pu under a full nominal power.

**Figure 13.**Simulation results of the LVRT proposed strategy for a symmetrical voltage sag of 0.1 pu under a half nominal power.

**Figure 14.**Simulation results of the proposed LVRT strategy for a symmetrical voltage sag of 0.3 pu under a full nominal power.

**Figure 15.**Simulation results of the proposed LVRT strategy for symmetrical voltage sag of 0.3 pu under a half nominal power.

**Figure 16.**Simulation results of the proposed LVRT strategy for an asymmetrical voltage sag of 0.1 pu under a full nominal power.

**Figure 17.**Simulation results of the proposed LVRT strategy for an asymmetrical voltage sag of 0.1 pu under a half nominal power.

**Figure 18.**Simulation results of the proposed LVRT strategy for an asymmetrical voltage sag of 0.5 pu under a full nominal power.

**Figure 19.**Simulation results of the proposed LVRT strategy for an asymmetrical voltage sag of 0.5 pu under a half nominal power.

DFIG System Parameters | |
---|---|

Rated Power | 2 MW |

Rated speed | 1500 tr/min |

Frequency | 50 Hz |

Grid voltage | 400 V (line-to-line) |

DC bus voltage | 800 V |

Stator resistance and inductance | 0.0026 Ω, 8.7e^{−2} mH |

Rotor resistance and inductance | 0.0029 Ω, 2.6 mH |

Mutual inductance | 0.0025 H |

Proportional constant of PI current regulator | 0.5771 |

Integral constant of PI current regulator | 491.5995 |

Power Parameters of the GSC | |
---|---|

Nominal DC voltage | V_{DC} = 800 V |

Switching frequency | f_{sw} = 24,416 Hz |

Line inductance | L = 0.15 mH |

AC system | Voltage amplitude V_{RST}: 400 V(rms) (line-to-line)Nominal frequency: 50 Hz |

Control Subsystem Parameters | |
---|---|

Constants of the proportional-resonant (PR) current regulators in α-β axes | k_{p,Iαβ} = 0.0011k _{i,Iαβ} = 0.1 |

Resonant and cut-off frequencies | ω_{o} = 314.16 rad/sω _{c} = 1 rad/s |

Constants of the proportional-integral (PI) voltage regulator | k_{p,VDC} = 3977.5k _{i,VDC} = 152,110 |

Sample times of the power and control subsystems | ${T}_{s}$ = 5.1196 μs ${T}_{reg}$ = 40.957 μs |

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**MDPI and ACS Style**

El Karkri, Y.; Rey-Boué, A.B.; El Moussaoui, H.; Stöckl, J.; Strasser, T.I.
Improved Control of Grid-connected DFIG-based Wind Turbine using Proportional-Resonant Regulators during Unbalanced Grid. *Energies* **2019**, *12*, 4041.
https://doi.org/10.3390/en12214041

**AMA Style**

El Karkri Y, Rey-Boué AB, El Moussaoui H, Stöckl J, Strasser TI.
Improved Control of Grid-connected DFIG-based Wind Turbine using Proportional-Resonant Regulators during Unbalanced Grid. *Energies*. 2019; 12(21):4041.
https://doi.org/10.3390/en12214041

**Chicago/Turabian Style**

El Karkri, Yassir, Alexis B. Rey-Boué, Hassan El Moussaoui, Johannes Stöckl, and Thomas I. Strasser.
2019. "Improved Control of Grid-connected DFIG-based Wind Turbine using Proportional-Resonant Regulators during Unbalanced Grid" *Energies* 12, no. 21: 4041.
https://doi.org/10.3390/en12214041