Research Keyword: Energy Storage

Aug 19

Nelder-Mead Simplex Algorithm for Age-dependent Parameter Estimation of a Lithium-ion Electrochemical Battery Model

The proliferation and prevalence of lithium ion batteries has produced a surge in research into electrochemical
cell models and the identification of specific unknown cell parameters. Accordingly, optimization methods have
become an area of intense investigation for their inherent ability to determine model parameter values which best
fit to observed data. With the ability to calculate lithium ion cell properties in real time, Battery Management
Systems (BMS) would exhibit significant improvements in decision making for prolonging batteries’ life span
and increasing efficient charging/discharging. The paper analyses the use of Nelder-Mead Simplex algorithm for
estimating three age-dependent parameters of a electrochemical cell model. Results indicate accurate parameter identification for simulation and experimental environments. With real time voltage measurements, applications such as electric vehicles and large power grid batteries would greatly benefit from the use of Nelder-Mead Simplex mentioned throughout this paper.

Aug 19

Analysis of A Fully Electric Tractor Performance Through Field Trials in Rwanda

Off-road agricultural vehicles contribute significantly to greenhouse gas (GHG) emissions including tractors which has not been considered in the past. While tractor operation poses threats to environment generally through toxic gas emissions, tractors are key components in mechanizing agriculture practices which satisfies food demand with an increased efficiency. This paper will shade more light on performance and viability of a fully electric tractor evaluated through several field trials

Aug 17

Experimental Research on Pulse Discharge Heating of Li-ion Battery

Lithium-ion batteries (LIBs) preheating is essential to restoring their power performance in cold weather. To make full use of the heating potential of pulse discharge and achieve the balance between heating performance and equipment cost, experiments are developed to explore the effects of average (avg) current, rms current, pulse frequency, and state of charge(SOC) on the temperature rise during preheating. It was found that within the frequency of 1kHz~10kHz and current rate less than 1C, which is most probably applied in practice, the heat generation was affected by all the factors above, among which the avg current had the highest impact. Entropy heat produced was more than the Joule heat produced and was the main contributor to the temperature rise. Therefore, it cannot be overlooked in heat generation model and simulation. As it varies greatly with the SOC, the temperature rise rate will be inconsistent when the DC pulse discharge is in the application, which will cause the user to experience an unpredictable preheating time.

Aug 01

Real-time Controller Hardware-in-the-Loop Testing of an Electric Vehicle Powertrain for Optimal Delivery of Energy Sources

This paper explores the adoption of electric vehicles (EVs) with particular emphasize on electric traction drive technologies. This work will then have a look at the different alternative solutions behind each electric vehicle motor drive and the reason behind a particular chosen type of motor, its control architecture to get the most performance out of the existing traction systems. The theoretical model prediction of what a real-world vehicle would perform is developed resembling when given ideal transient conditions applied and then simulate an EV power distribution system hybridizes the PV solar and battery resources in a real-time manner. The developed model is constructed through MATLAB/Simulink and executed on real-time hardware setup. It includes distributed energy resources (DERs: Battery, Solar Photovoltaic) and its associated power electronics DC-DC converter and controls, DC-AC inverter to drive the interior permanent magnet synchronous motor (IPMSM). The drivetrain control scheme includes both speed, max torque-per-ampere and field weakening controllers to offer EV operation within extended speed and torque ranges comparable to available EV technologies such as BMW iX3. Different operating scenarios are evaluated deploying controller HIL and the obtained results validated the theoretical expectations and overall performance of the studied self-charging EV drive system.

Jul 24

State-of-the-Art Wireless Charging Systems for e-Bikes: Technologies and Applications

Several advancements were made in wireless charging for e-transportation however, the knowledge acquired in the context of wireless charging of electric cars are not sufficient to apply to electric bicycle (e-bikes). Therefore, this paper reviewed state-of-the-art wireless charging technologies with a special emphasis on e-bike charging. A comparative analysis of different kinds of wireless charging techniques is also presented to provide a clear understanding and guidelines to choose the best suitable technology for implementation. In addition, current issues, challenges, and future research scopes are identified where necessary modifications need to be done before implementing the technology for e-bikes.

Jul 23

Bi-directional Three Phase Zero Voltage Soft-Switching Converter

This digest proposes a DC side active clamping branch with a clamping capacitor in series with two switches in a common source connection to realize zero voltage soft-switching (ZVS) for a bi-directional two level three phase converter. Moreover, conventional space vector modulation technique is modified to realize ZVS for a bi-directional two level three phase converter. Utilizing the modified space vector modulation (MSVM) technique, bi-directional converter can achieve ZVS for all switching devices in both inverter and rectifier modes of operation. The MSVM technique allows all the switches including in; main converter and auxiliary circuit operate at the same switching frequency. Moreover, simulation results are presented in this digest. Furthermore, laboratory scaled prototype of the bi-directional ZVS converter is assembled rated for 20-kW to experimentally verify the theoretical analysis.

Jul 23

THREE-PORT HIGH VOLTAGE CONVERSION RATIO DC-DC CONVERTER

In this paper, a new three-port DC-DC converter with high voltage conversion ratio is proposed. The proposed converter is useful for photovoltaic (PV) systems, which have a PV source integrated with an extra battery source to supply the output load. The voltage conversion ratio of the high dc voltage port over the low voltage dc port can be more increased by increasing the turns ratio of the coupled inductors for the whole range of duty cycles. The main advantage of the proposed converter comparing to other conventional three-port converters, is achieving higher voltage gain and higher ratio of voltage gain over components’ number. The proposed converter has also the leased normalized voltage stresses on switches for duty cycles higher than 0.3 among the conventional converters of the same type. Moreover, two output voltages of the proposed converter can be simultaneously regulated on different constant levels with a proper precision. In this study, the proposed converter is analyzed and the voltage conversion ratios, the inductors’ average currents, the voltage and current stress on switches are calculated theoretically. Finally, to verify the operation of the proposed converter, the experimental and simulation results of 20V/40V/400V prototype are extracted.

Jul 22

Inter-cluster Power Control of Modular Multilevel Converters with Integrated Battery Energy Storage for Low AC Voltage Operation

This paper presents a method to operate each MMC cluster with independent powers during low ac voltage operation. The method reduces the use of circulating current in low voltage conditions. This facilitatates the state of charge balance of MMCs with integrated BESS in the clusters for such conditions. The method is proposed for EVs but other applications could eventually make use of it.

Jul 22

Manipulation of Actual Demand in Electric Vehicles (MAD EV): A Cyber Security Perspective

This paper defines and analyses a specific cybersecurity risk for EVs, which we refer to as Manipulation of Actual Demand. This attack involves coordinated charging of a large number of EVs across multiple charging stations to disrupt the power grid. We provide a detailed analysis and quantification of the impact of this unique cyber-attack on the smart grid in terms of demand-side load. The findings of our analysis guide future considerations on cybersecurity risks of coordinated EV charging and their mitigation. We have made a comparison between Home EV chargers and Fast EV chargers via simulation. The results indicate the EV demand load threshold required to disrupt normal power grid operations

Jul 22

The Multidimensional Battery Management Strategy for MMC Battery Energy Storage System

The previous state-of-charge (SOC) and state-of-health (SOH) management strategies for battery energy storage system based on the modular multilevel converter (MMC-BESS) normally work separately. With the diversification and complexity of energy storage application scenarios in AC/DC hybrid grid, it is necessary to develop more flexible battery management strategies for different scenarios. In this paper, a multidimensional battery management strategy is developed, which takes into account both SOC and SOH, and also considers both intra-submodule (intra-SM) equalizing and inter-SM balancing. Experiments are presented to verify the proposed strategy for MMC-BESS.