Article
Optimal Scheduling Strategy of AC/DC Hybrid Distribution
Network Based on Power Electronic Transformer
Qingwen Peng, Lu Qu * , Zhichang Yuan, Xiaorui Wang, Yukun Chen and Baoye Tian
Citation: 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
Academic Editor: Pierluigi Siano
Received: 20 April 2021
Accepted: 27 May 2021
Published: 31 May 2021
Publisher’s Note: MDPI stays neutral
with regard to jurisdictional claims in
published maps and institutional affil-
iations.
Copyright: © 2021 by the authors.
Licensee MDPI, Basel, Switzerland.
This article is an open access article
distributed under the terms and
conditions of the Creative Commons
Attribution (CC BY) license (https://
creativecommons.org/licenses/by/
4.0/).
State Key Lab of Power Systems, Department of Electrical Engineering, Tsinghua University,
Beijing 100084, China; pengqw@tsinghua.edu.cn (Q.P.); yuanzhc@tsinghua.edu.cn (Z.Y.); wxr_fr@163.com (X.W.);
chenyk20@mails.tsinghua.edu.cn (Y.C.); tianby@tsinghua.edu.cn (B.T.)
* Correspondence: qulu@tsinghua.edu.cn
Abstract:
The AC/DC hybrid distribution network is composed of a medium-voltage DC bus, a
low-voltage DC bus, and a power electronic transformer, and has the characteristics of multi-voltage
level, multi-DC bus, and multi-converter, so its operation mode and optimal scheduling strategy are
more complex. Firstly, this paper constructs the AC/DC hybrid distribution network using an power
electronic transformer. Then, a two-layer control structure including a scheduling management layer
and a bus control layer is proposed, which simplifies the control structure and gives full play to
the role of “energy routing” function of the power electronic transformer. Moreover, the minimum
operation cost of the AC/DC hybrid distribution network in the whole scheduling cycle is taken
as the optimization objective, considering the characteristics of various distributed generations, the
structure of AC/DC hybrid distribution network, and the interaction of “source–load–storage”.
Finally, the optimal scheduling model of the AC/DC hybrid distribution network based on power
electronic transformer is established, and the feasibility of the optimal scheduling strategy is verified
by the open-source solver, which can realize the complete absorption of renewable energy and the
optimal coordinated control of “source–load–storage”.
Keywords:
optimal scheduling strategy; AC/DC hybrid distribution network; power electronic trans-
former
1. Introduction
With the development of distribution network, the increase of DC load, the increas-
ingly extensive application of energy storage, the problems of high AC/DC energy con-
version loss, and the poor flexibility of the distribution network in the traditional AC
distribution network have become increasingly prominent. In addition, with the high
requirements of customers for power quality and supply reliability, the traditional AC
distribution network will encounter new challenges in terms of stability and economy
in power supply, and it is unable to meet the ever-changing demand for DC power and
electricity uses. The AC/DC hybrid distribution network has the advantages of flexible
power scheduling, high system efficiency, large power capacity, low line loss, high power
quality, and reactive power compensation. Moreover, it is suitable for distributed genera-
tion, energy storage devices, and DC loads to access flexibly; helps to solve a series of new
problems in the development of traditional AC distribution network; and is important in
developing the direction of the power distribution network [1–5].
Due to the integration of distributed generation, energy storage, grid connected in-
verter, and various loads in the AC/DC hybrid distribution network, and considering
the intermittence of the distributed generation, the stable operation of the network is
closely related to the coordinated control of each power supply. References [
6
–
16
] propose
various coordinated control strategies, which can be divided into two types: centralized
coordinated control strategy and distributed coordinated control strategy. The centralized
Energies 2021, 14, 3219. https://doi.org/10.3390/en14113219 https://www.mdpi.com/journal/energies
