Coordination of a Flywheel Energy Storage Matrix System: An External Model Approach

Haiming Liu,He Cai,Huanli Gao,Shuping Guo

doi:10.1109/access.2021.3061743

Abstract

This paper studies the coordination of a heterogenous flywheel energy storage matrix system aiming at simultaneous reference power tracking and state-of-energy balancing. It is first revealed that this problem is solvable if and only if the state-of-energy of all the flywheel systems synchronize to a common time-varying manifold governed by a nonautonomous dynamic system. Next, by treating this nonautonomous dynamic system as an external model, the coordination problem can be decoupled into two separate problems, namely, the global double layer estimation problem and the local tracking problem. Then, a distributed control scheme is proposed to solve the coordination problem by integrating the adaptive distributed observer approach and the certainty equivalence control method. Comprehensive case studies are provided to show the performance of the proposed control scheme.

Highlights

Flywheel energy storage system (FESS) is an important type of energy storage system which is indispensable to modern power system by maintaining balance between power supply and demand [1]–[4]
For a heterogenous flywheel energy storage matrix system (FESMS), a coordination problem aiming at simultaneous reference power tracking and state-of-energy balancing has been considered
It is first revealed that there exists a common time-varying manifold governed by a nonautonomous dynamic system which guarantees the solution to the coordination problem

Summary

INTRODUCTION

Flywheel energy storage system (FESS) is an important type of energy storage system which is indispensable to modern power system by maintaining balance between power supply and demand [1]–[4]. To the best of the author’s knowledge, this paper for the first time considers the coordination problem of a heterogenous FESMS aiming at simultaneous reference power tracking and SOE balancing. The nonautonomous dynamic system which gives rise to the common time-varying manifold is depicted by all these parameters In other words, these parameters implicitly determine how the reference power is shared among all the flywheel systems within the FESMS. It is shown that the proposed control scheme is able to work under jointly connected communication network. Remark 2: The control objective (3) requires that the power output of the entire FESMS should follow its reference, and the control objective (4) requires that the SOE of all the flywheel systems should be balanced. In this work, PREF (t) is assumed to be generated by the command generator (2), which can accommodate a large class of reference signals as well as their combinations, such as step signals of arbitrary magnitudes, sinusoidal signals of arbitrary initial phases and amplitudes, and polynomial signals of arbitrary curve rates

MAIN RESULTS

PROBLEM SOLVABILITY Lemma 1

STABILITY ANALYSIS Theorem 1

CASE STUDIES

STANDARD CASE

CONCLUSION