# A Combined RMS Simulation Model for DFIG-Based and FSC-Based Wind Turbines and Its Initialization

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## Abstract

**:**

## 1. Introduction

#### 1.1. Motivation

#### 1.2. Background

- -
- Based on fundamental machine and converter equations and therefore reconstructable and comparable independent from simulation platforms;
- -
- Utilizes analogies and modularity in the development of components and their control systems, avoiding the impact of differences in modeling when comparing different WT technologies (DFIG-based, FSC-based);
- -
- Reduced to the essential components and essential parameter set and therefore easy to supplement with control features (e.g., fault ride through capability, fast fault current injection, fast frequency response, etc.) required for answering specific research questions;
- -
- Exact initialization procedure occurs without transients, which makes the model well-suited for use in large-scale dynamic simulations.

#### 1.3. Contribution of This Article

- -
- To add a model for the machine-side converter (MSC) controller of the FSC-based WT, which allows consideration of impact of the rotating mass and the induction generator and therefore makes the model suitable for a broad variety of stability analyses (incl. frequency stability; see case study in Section 6.).
- -
- To provide exact initialization procedures, which are important especially for large-scale system studies but are very rarely addressed in the literature.

## 2. RMS Simulation

## 3. Wind Turbine Model

#### 3.1. Shared Sub-Modules

#### 3.1.1. Aerodynamic and Drive Train Model

#### 3.1.2. Induction Generator

#### 3.1.3. Pitch and Speed Controller

#### 3.1.4. Grid-Side Converter Controller

#### 3.2. Special Features of Doubly Fed Induction-Generator-Based Wind Turbine

#### Machine-Side Converter Controller

#### 3.3. Special Features of Full-Scale-Converter-Based Wind Turbine

#### Machine-Side Converter Controller

#### 3.4. Model Interfacing

#### 3.4.1. Wind Turbine Models—Grid Model

#### 3.4.2. Converter Models-Converter Controller Models

## 4. Initialization

#### 4.1. DFIG-Based Wind Turbine

#### 4.1.1. DFIG

#### 4.1.2. Aerodynamic and Drive Train Model

#### 4.1.3. GSC

#### 4.2. FSC-Based Wind Turbine

#### 4.2.1. SCIG

#### 4.2.2. Aerodynamic and Drive Train Model

#### 4.2.3. GSC

## 5. Fast Frequency Response

## 6. Case Study

## 7. Discussion

## 8. Conclusions

## Author Contributions

## Funding

## Institutional Review Board Statement

## Informed Consent Statement

## Conflicts of Interest

## Abbreviations

DFIG | Doubly fed induction generator |

EMT | Electromagnetic transient |

FAPI | Fast active power injection |

FFR | Fast frequency response |

FN | Frequency nadir |

FSC | Full-scale convertor |

GSC | Grid-side converter |

MSC | Machine-side converter |

PEGU | Power electronic-interfaced generating units |

PLL | Phase-locked loop |

PPM | Power park module |

RMS | Root mean square |

ROCOF | Rate of change of frequency |

SCIG | Squirrel-cage induction generator |

SI | Synthetic inertia |

VSC | Voltage-sourced converter |

WT | Wind turbine |

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**Figure 4.**(

**a**) Electrical equation system of induction generator; (

**b**) Norton equivalent circuit of induction generator.

**Figure 7.**(

**a**) Block diagram of the GSC controller; (

**b**) Structure of a back-to-back frequency converter.

**Figure 11.**Phasor diagram of SCIG for an assumed operating point in various rotating reference frames.

DFIG-Based WTs | High Availability |
---|---|

FSC-based WTs (synchronous generator) | middle availability |

FSC-based WTs (induction generator) | only one reference [5] |

Sub-Modules | References |
---|---|

Aerodynamic model | [4,6,7] |

Drive train model | Based on [3,8] |

Induction generator | [9,10] |

Pitch controller | Based on [3,11] |

Speed controller | Based on [8] |

Power–speed tracking characteristic | Based on [4,12] |

GSC controller | Based on [8] |

MSC controller (DFIG-based WT) | Based on [8,13] |

MSC controller (FSC-based WT) | Contribution of this work |

Initialization (DFIG-based WT) | Contribution of this work |

Initialization (FSC-based WT) | Contribution of this work |

SG1 | SG2 | SG3 | WP1 | WP2 | L1 | L2 | L3 | L4 | |
---|---|---|---|---|---|---|---|---|---|

Active power in MW | 347 | 400 | 400 | 80 | 80 | 300 | 350 | 350 | 300 |

Reactive power in Mvar | 87 | 77 | 80 | 16 | 16 | 20 | 25 | 30 | 20 |

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**MDPI and ACS Style**

Goudarzi, F.; Hofmann, L. A Combined RMS Simulation Model for DFIG-Based and FSC-Based Wind Turbines and Its Initialization. *Energies* **2021**, *14*, 8048.
https://doi.org/10.3390/en14238048

**AMA Style**

Goudarzi F, Hofmann L. A Combined RMS Simulation Model for DFIG-Based and FSC-Based Wind Turbines and Its Initialization. *Energies*. 2021; 14(23):8048.
https://doi.org/10.3390/en14238048

**Chicago/Turabian Style**

Goudarzi, Farshid, and Lutz Hofmann. 2021. "A Combined RMS Simulation Model for DFIG-Based and FSC-Based Wind Turbines and Its Initialization" *Energies* 14, no. 23: 8048.
https://doi.org/10.3390/en14238048