# Optimal Scheduling Strategy of AC/DC Hybrid Distribution Network Based on Power Electronic Transformer

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## Abstract

**:**

## 1. Introduction

## 2. AC/DC Hybrid Distribution Network

#### 2.1. Topology

#### 2.2. Control Structure

## 3. Scheduling Management

#### 3.1. The Objective Function

#### 3.1.1. Distributed Generation Operating Cost

#### 3.1.2. Photothermal System Operating Cost

#### 3.1.3. Power Purchase Cost

#### 3.1.4. Compensation Cost of Controllable Load

#### 3.2. Constraints

#### 3.2.1. Power Balance Constraints

#### 3.2.2. Exchange Power Constraints

#### 3.2.3. Photovoltaic Power Constraints

#### 3.2.4. Wind Power Constraints

#### 3.2.5. Storage System Constraints

#### 3.2.6. Solar Thermal System Power Constraints

#### 3.2.7. Reducible Load Constraints

#### 3.3. Control Structure

## 4. Bus Control

#### 4.1. DC Microgrid

#### 4.2. AC Microgrid

## 5. Case Analysis

#### 5.1. System Configuration

#### 5.2. Case Solving

#### 5.3. Result Analysis

## 6. Conclusions

## Author Contributions

## Funding

## Institutional Review Board Statement

## Informed Consent Statement

## Data Availability Statement

## Acknowledgments

## Conflicts of Interest

## Appendix A

**Figure A1.**The curve of daily load comes from the data of bus load measured by a substation in December.

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**Figure 6.**Optimal scheduling results of AC/DC hybrid distribution system. (

**a**) Voltage of low-voltage DC side of power electronic transformer. (

**b**) Predicted and actual wind power. (

**c**) Predicted and actual PV power. (

**d**) Charging and discharging power of energy storage. (

**e**) SOC of power storage. (

**f**) Photothermal system. (

**g**) Exchange power between AC/DC hybrid distribution system and AC main network. (

**h**) Load.

**Figure 7.**Exchanging power between AC/DC hybrid distribution network and AC main network without power electronic transformer.

Control Mode | Distributed Power Converter | Storage Power Converter | Power Electronic Transformer | Reducible Load Converter |
---|---|---|---|---|

1 | Droop control | Charging | Limit exchange power | Normal operation |

2 | MPPT | Charging under droop | Limit exchange power | Normal operation |

3 | MPPT | Charging/discharging | Droop control exchange power | Normal operation |

4 | MPPT | Charging under droop | Limit exchange power | Normal operation |

5 | MPPT | Discharging | Limit exchange power | Droop control |

Type of Distributed Power | Capacity (kW) | Rated Power (kW) | Service Life (year) | Investment Cost (RMB/kWh) | Operation Cost (RMB/kWh) | Annual Utilization Hours (h) | Depreciation Rate (%) |
---|---|---|---|---|---|---|---|

Photovoltaic | 2000 | 1500 | 25 | 6,000,000 | 0.015 | 2000 | 8 |

Wind power | 40 | 30 | 20 | 144,000 | 0.005 | 1800 | 8 |

Storage | 500 | 400 | 15 | 1,502,500 | 0.0013 | 8760 | 8 |

Solar collector | 100 | 80 | 20 | 320,000 | 0.017 | 6000 | 8 |

Solar collector | 5 | 4 | 15 | 20,000 | 0.003 | 6000 | 8 |

Lithium absorption chiller | 10 | 8 | 20 | 60,000 | 0.001 | 6000 | 8 |

Thermal storage | 20 | 16 | 20 | 100,000 | 0.001 | 8760 | 8 |

Storage power | Total battery limit: 500 kWh Charging/discharging efficiency: 93.81% Power storage SOC: 5–95% Initial power storage: 50 kWh Maximum number of charging and discharging in the scheduling period: 1.5 times |

Thermal storage | Total calories: 200 kWh Thermal storage SOC: 5–95% Thermal charging/discharging efficiency: 95% Thermal dissipation coefficient: 0.6% |

Reducible Load | Unit compensation: 1.1 RMB/kWh Maximum power reduction: 200 kW Maximum sustainable time: 2 h Minimum duration: 0.5 h Reducible time: 18:00–23:00 Limit of reducible times: 2 times |

Photothermal system | Ascent rate limit: 10 kW/h Downhill rate limit: −10 kW/h Maximum number of starts and stops: 4 times Minimum continuous running time: 3 h |

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**MDPI and ACS Style**

Peng, Q.; Qu, L.; Yuan, Z.; Wang, X.; Chen, Y.; Tian, B.
Optimal Scheduling Strategy of AC/DC Hybrid Distribution Network Based on Power Electronic Transformer. *Energies* **2021**, *14*, 3219.
https://doi.org/10.3390/en14113219

**AMA Style**

Peng Q, Qu L, Yuan Z, Wang X, Chen Y, Tian B.
Optimal Scheduling Strategy of AC/DC Hybrid Distribution Network Based on Power Electronic Transformer. *Energies*. 2021; 14(11):3219.
https://doi.org/10.3390/en14113219

**Chicago/Turabian Style**

Peng, Qingwen, Lu Qu, Zhichang Yuan, Xiaorui Wang, Yukun Chen, and Baoye Tian.
2021. "Optimal Scheduling Strategy of AC/DC Hybrid Distribution Network Based on Power Electronic Transformer" *Energies* 14, no. 11: 3219.
https://doi.org/10.3390/en14113219