TY - JOUR
T1 - Efficient Improvement of Photovoltaic-Battery Systems in Standalone DC Microgrids Using a Local Hierarchical Control for the Battery System
AU - Yang, Yun
AU - Qin, Yaxiao
AU - Tan, Siew Chong
AU - Hui, Shu Yuen Ron
N1 - Funding Information:
Manuscript received November 3, 2018; revised January 9, 2019; accepted February 13, 2019. Date of publication February 18, 2019; date of current version August 29, 2019. This work was supported by Hong Kong Research Grant Council under the theme-based research Project T23-701/14-N. Recommended for publication by Associate Editor G. Oriti. (Corresponding author: Yun Yang.) Y. Yang, Y. Qin, and S.-C. Tan are with the Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong (e-mail:, [email protected]; [email protected]; [email protected]).
Publisher Copyright:
© 1986-2012 IEEE.
Copyright:
Copyright 2019 Elsevier B.V., All rights reserved.
PY - 2019/11
Y1 - 2019/11
N2 - The conventional control methods for the battery systems of photovoltaic (PV) battery systems in standalone dc microgrids are designed to stringently regulate the bus voltages at the maximum power points (MPP) of PV modules while the state of charge (SOC) of the battery packs is regulated within the tolerances. In this paper, a local hierarchical control (LHC) is proposed for the battery system to improve the energy efficiency of the entire PV-battery system at the MPP of PV modules while the SOC of the battery pack is still regulated within the tolerance. Specifically, by allowing the dc bus voltage to deviate within a preset allowable tolerance, the secondary control of the LHC is employed to compute real-time optimal references to its primary control, such that the energy conversion of the entire PV-battery system can be optimized. Simulation studies exhibit significant efficiency improvement of a 12-PV-battery system under both uniform and nonuniform insolation conditions on a cloudy day and a 600-kW PV-battery system on a sunny day using the proposed LHC. Experimental results validate that the energy efficiency of a single-PV-module-battery system controlled by the LHC can be enhanced using shortened sunny-day and cloudy-day irradiance profiles for various PV modules. The proposed control scheme can be easily implemented in digital controllers without additional hardware costs.
AB - The conventional control methods for the battery systems of photovoltaic (PV) battery systems in standalone dc microgrids are designed to stringently regulate the bus voltages at the maximum power points (MPP) of PV modules while the state of charge (SOC) of the battery packs is regulated within the tolerances. In this paper, a local hierarchical control (LHC) is proposed for the battery system to improve the energy efficiency of the entire PV-battery system at the MPP of PV modules while the SOC of the battery pack is still regulated within the tolerance. Specifically, by allowing the dc bus voltage to deviate within a preset allowable tolerance, the secondary control of the LHC is employed to compute real-time optimal references to its primary control, such that the energy conversion of the entire PV-battery system can be optimized. Simulation studies exhibit significant efficiency improvement of a 12-PV-battery system under both uniform and nonuniform insolation conditions on a cloudy day and a 600-kW PV-battery system on a sunny day using the proposed LHC. Experimental results validate that the energy efficiency of a single-PV-module-battery system controlled by the LHC can be enhanced using shortened sunny-day and cloudy-day irradiance profiles for various PV modules. The proposed control scheme can be easily implemented in digital controllers without additional hardware costs.
KW - Local hierarchical control (LHC)
KW - photovoltaic (PV) battery system
KW - standalone dc microgrid
UR - http://www.scopus.com/inward/record.url?scp=85072060841&partnerID=8YFLogxK
U2 - 10.1109/TPEL.2019.2900147
DO - 10.1109/TPEL.2019.2900147
M3 - Journal article
AN - SCOPUS:85072060841
SN - 0885-8993
VL - 34
SP - 10796
EP - 10807
JO - IEEE Transactions on Power Electronics
JF - IEEE Transactions on Power Electronics
IS - 11
M1 - 8643805
ER -