Energy Dispatch Controllers for a Photovoltaic System

Abstract

In this paper two energy dispatch controllers for use in a grid-independent photovoltaic (PV) system are presented. the first, an optimal energy dispatch controller, is based on a class of Adaptive Critic Designs (ACDs) called Action Dependent Heuristic Dynamic Programming (ADHDP). This class of ACDs uses two neural networks to evolve an optimal control strategy over time. the first neural network or "Action" network dispenses the actual control signals while the second network or "Critic" network uses these control signals along with the system states to provide feedback to the action network, measuring performance using a utility function. This feedback loop allows the action network to improve behavior over time. the optimal energy dispatcher places emphasis on always meeting the critical load, followed by keeping the charge of the battery as high as possible so as to be able to power the critical load in cases of extended low output from the PV array, and lastly to power the non-critical load in so far as to not interfere with the first two objectives. the second energy dispatch controller is a smart energy dispatch controller and is built using knowledge from an expert, codified into a series of static rules. This smart energy dispatch controller is called the "PV-priority 2" controller. These energy dispatchers are compared with a static scheme called the "PV-priority 1". the PV-priority 1 controller represents the standard control strategy. Results show that the ADHDP-Based optimal energy dispatcher (or controller) outperforms the standard PV-priority 1 energy dispatcher in meeting the stated objectives, but trails the PV-priority 2 energy dispatcher. However, the major advantage of the ADHDP controller is that no expert is required for designing the controller, whereas for a rule-Based controller such as the PV-priority 2 controller, an expert is always required. © 2009 Elsevier Ltd.

Department(s)

Electrical and Computer Engineering

Comments

National Science Foundation, Grant ECCS 0348221

Keywords and Phrases

Adaptive critic design; Energy dispatch controller; Neural network; Photovoltaic; PV-priority controller; Solar

International Standard Serial Number (ISSN)

0952-1976

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2024 Elsevier; International Federation of Automatic Control (IFAC), All rights reserved.

Publication Date

01 Mar 2010

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