Citation: Fan, P.; Ke, S.; Kamel, S.;
Yang, J.; Li, Y.; Xiao, J.; Xu, B.; Rashed,
G.I. A Frequency and Voltage
Coordinated Control Strategy of
Island Microgrid including Electric
Vehicles. Electronics 2022, 11, 17.
https://doi.org/10.3390/
electronics11010017
Academic Editors:
Luis Hernández-Callejo,
Sergio Nesmachnow and
Sara Gallardo Saavedra
Received: 5 December 2021
Accepted: 20 December 2021
Published: 22 December 2021
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4.0/).
Article
A Frequency and Voltage Coordinated Control Strategy of
Island Microgrid including Electric Vehicles
Peixiao Fan
1
, Song Ke
1,
*, Salah Kamel
2
, Jun Yang
1
, Yonghui Li
1
, Jinxing Xiao
3
, Bingyan Xu
3
and Ghamgeen Izat Rashed
1
1
School of Electrical Engineering and Automation, Wuhan University, Wuhan 430072, China;
whufpx0408@163.com (P.F.); JYang@whu.edu.cn (J.Y.); whusee2006@yahoo.com (Y.L.);
ghamgeen@whu.edu.cn (G.I.R.)
2
Electrical Engineering Department, Faculty of Engineering, Aswan University, Aswan 81542, Egypt;
skamel@aswu.edu.eg
3
Electric Power Company of Shanghai, State Grid, Shanghai 200122, China; xjx1122@163.com (J.X.);
gh197493@yahoo.com (B.X.)
* Correspondence: kesong1997@whu.edu.cn; Tel.: +18-771-043566
Abstract:
Frequency and voltage deviation are important standards for measuring energy indicators.
It is important for microgrids to maintain the stability of voltage and frequency (VF). Aiming at the
VF regulation of microgrid caused by wind disturbance and load fluctuation, a comprehensive VF
control strategy for an islanded microgrid with electric vehicles (EVs) based on Deep Deterministic
Policy Gradient (DDPG) is proposed in this paper. First of all, the SOC constraints of EVs are added
to construct a cluster-EV charging model, by considering the randomness of users’ travel demand
and charging behavior. In addition, a four-quadrant two-way charger capacity model is introduced
to build a microgrid VF control model including load, micro gas turbine (MT), EVs, and their random
power increment constraints. Secondly, according to the two control goals of microgrid frequency
and voltage, the structure of DDPG controller is designed. Then, the definition of space, the design
of global and local reward functions, and the selection of optimal hyperparameters are completed.
Finally, different scenarios are set up in an islanded microgrid with EVs, and the simulation results
are compared with traditional PI control and R(
λ
) control. The simulation results show that the
proposed DDPG controller can quickly and efficiently suppress the VF fluctuations caused by wind
disturbance and load fluctuations at the same time.
Keywords: islanded microgrid; electric vehicles; charger capacity model; VF control; DDPG
1. Introduction
Microgrid refers to a small power generation and distribution system that is composed
of distributed power sources, energy storage devices, energy conversion devices, related
loads, monitoring, and protection devices. It is an autonomous system that can realize
self-control, protection, and management. In addition, the microgrid can operate in grid-
connected mode and islanded mode. In islanded mode, the power quality of the microgrid
is usually maintained by the micro sources and flexible loads [
1
]. At the same time, with
the development of vehicle-to-grid (V2G) technology, the research of EVs in the areas of
grid peak and valley filling, suppression of power fluctuations, and microgrid stability
control has also been deepened [
2
,
3
], which brings opportunities and challenges to the VF
regulation of microgrids.
Due to the limited capacity of the islanded microgrid, ensuring the stability of fre-
quency and voltage is the key for the operation safety of microgrid. In [
4
], a VF strategy of
an islanded microgrid based on fuzzy logic controller is proposed, which can control active
and reactive powers and decrease power losses of the microgrid, thus the effectiveness
and robustness of the proposed controller over the conventional proportional- integral
controller. In [
5
], a decoupled VF controller for DGs is proposed, which is able to keep the
Electronics 2022, 11, 17. https://doi.org/10.3390/electronics11010017 https://www.mdpi.com/journal/electronics
