Research Keyword: Energy Storage

Jul 17

A Novel Grid-friendly Vehicle-to-Grid Solution for Power Grid with Large-scale Renewable Fuel Vehicles

This paper presents a novel concept, named as smart mobile power bank, to implement grid-friendly vehicle-to-Grid technology. The concept and principle of mobile power bank is first developed, where multi-port DC/DC converter is developed to integrate hybrid energy storage system, photovoltaic panels, and various renewable fuel vehicles in a form of DC microgrid. Further, the operation and control strategy are developed to enable the proposed SMPB. The proposed solution is able to improve the security, flexibility and economy for power grid with high penetration of renewable fuel vehicles.

Jul 14

High Voltage Battery Management System Hardware and Software Design for Photovoltaic Energy Systems

The energy that is generated from renewable energy systems is usually stored in high-energy lithium-ion battery storage systems so that it is optimal to use high voltage batteries to decrease the current, and then eventually to have minimum power loss. Therefore, in this paper, 200V battery management system (BMS) hardware and software design are discussed. This paper proposes a 3-level flying capacitor DC-DC converter in the hardware design and SoC estimation algorithm in the software design by using simulation and test results. In this paper, the contribution is in the estimation method and in the DC-DC converter.

Jul 08

Joint SOC/Parameter Estimation for Wireless Battery Management Systems

We propose an online algorithm to estimate the state of charge (SOC) and parameters of lithium-ion batteries suitable for wireless battery management systems with low requirements on data transmission rates. We assume the voltage measurement of each battery cell and the battery pack current are quantized before being sent to the battery management system. A conventional equivalent circuit model of batteries is augmented with system parameters, and we analyzed its observability. We found although this augmented model is not observable in linear sense, it is fully observable based on a nonlinear observability analysis. Hence, two nonlinear observers are designed, based on the unscented Kalman filter and the ensemble Kalman filter, respectively. Using the experimental data, we show that based on the designed algorithms, the requirements on transmitting voltage measurement data for estimating battery SOC and parameters can be reduced from 11 bits per sample to 4 bits per sample, while the error of battery SOC estimation can be limited to 0.5%.

Jul 01

Advanced Systems Integration of 540 KVA Inverter and 1.86 MWh Battery Storage System: Testing and Overview

This paper focuses on the realization of advanced systems integration that has 540 KVA three-phase bidirectional inverter and 1863.68 kWh lithium-ion battery storage system at Florida Solar Energy Center (FSEC) with a partnership of University of Central Florida (UCF) and A.F. Mensah Inc. The purpose of this paper is to give the testing results and an overview of advanced systems integration on existing high-power state-of-art systems. It enables the reader to understand what to expect when considering to use of renewable energy with a battery energy storage system (BESS). After explaining each system, the real energy consumption and reduced energy consumption are demonstrated along with the battery testing results. The system’s reliability is also achieved at different power management scenarios which is also important for frequency regulation because the utility has access to the batteries, and they can be utilized during high-power demand in the area. As a result, these types of integrated systems promote the smart cities.

Jun 30

Photovoltaic Microinverter with Hybrid Energy Storage System (HESS) and Virtual Impedance Control for Injection into a Microgrid

This research provides a form of linear control, using exact linearization to manage the charging and discharging of the energy storage elements (Battery/UC), the tracking of the maximum power point and the injection of power to a microgrid. The use of exact linearization allows working with a wide operating range, unlike other linearizations that require approximations and allow working only in a single operating point. In addition, the proposed control is complemented by incorporating a virtual impedance block to reduce overshoot and accelerate the steady state response.

Jun 28

A Model-Based Control Strategy to Minimize Transient Oscillations at Load Steps for Current-Fed Triple-Active-Bridge DC-DC Converters

So far, current transients in the boost inductors of current-fed triple-active-brigde (CFTAB) converters are often accepted or ignored in the literature as the considered time interval of simulation and measurement results is typically very large so that the transient behavior of the current is not visible.

In this work, a model-based control strategy is presented that minimizes transient current oscillations in the boost inductors of CFTAB converters after a load step, which improves the dynamic performance of the converter drastically and furthermore prevents saturation and additional losses.

Jun 23

Digest Paper- “Modelling and Optimized Placement of a (Li-Ion battery)-based Grid Scale Energy Storage System for the Kenyan Grid”

Every grid is different in its own right; different number of buses, different voltages and different
dynamics in terms of loading. This means there is potentially myriads of studies that can be
conducted on grids considering this factor alone. That said, no study has been conducted on GSES
in the Kenyan Grid.
Most of the studies that have been conducted have mainly focused on RES integration rather than
potential benefits to a grid already integrated with RES; this study aims to bridge this gap.
Studies that have been conducted thus far have come up with possible case scenarios to determine
placement and benefits of said placement of BESS without applying prevailing conditions. This
study aims to scrutinize dispatch characteristics in the Kenyan grid to determine opportunities for
placement of BESS for a more targeted approach.
It is also observed in literature that no study has been done on stacking arbitrage and peak capacity
service provision combination and this study aims to do that.

Jun 22

Control of series-cascaded grid-forming microgrid configuration with a storage device

With the increase of inverter-based energy resources in power grids, it is imperative that the frequency stability is maintained and inverters can be controlled to improve frequency damping by using grid-forming inverters (GFM). The microgrid that is formed by several DGs that are connected in series is called a series topology microgrid. The series topology with individual LC output filters benefits from utilizing lower and different dc-link voltages. One of the drawbacks in series topologies is that the series cascaded DG microgrids have rarely been discussed when it comes to a different configuration combinations of DGs such as dispatchable and non-dispatchable DGs. In this paper, a comprehensive study of series-cascaded microgrid configuration consisting of master and slave DGs with a storage device is done. The power circuit, control circuit, and result are shown.