Analysis of energy usage for RTG cranes

The purpose of this paper is to study and analyse the energy that is used by the various motors of a crane of the Rubber Tyred Gantry type. For this reason a single Rubber Tyred Gantry (RTG) crane has been instrumented at port of Felixstowe and data has been collected during normal operation for eight days. This data has been analysed in terms of active and idle modes and also in terms of energy usage by the various motors. From this analysis it is possible to determine that on average about half of the energy consumed is potentially recoverable. It is also estimated that the recovery of this proportion of energy could lead to savings of 32,600 L of fuel and 8100 tonnes of CO2 per year at Port of Felixstowe

Motor Drive Stabilization in its Chaotic Region

The paper is concerned with the stability analysisand the control of chaos in a permanent magnet dc drivesystem. The stability analysis is based on the eigenvalues ofthe Jacobian matrix of the Poincare Map Function (PMF).Using the auxiliary state vector, the Jacobian matrix can bedetermined without the derivation of the PMF. Acompensating ramp signal is used to avoid bifurcation. Theslope of the ramp signal is also determined by the auxiliarystate vector. The results are verified by computersimulations in the time domain

Optimal Power Management Strategy for Energy Storage with Stochastic Loads

In this paper, a power management strategy (PMS) has been developed for the control of energy storage in a system subjected to loads of random duration. The PMS minimises the costs associated with the energy consumption of specific systems powered by a primary energy source and equipped with energy storage, under the assumption that the statistical distribution of load durations is known. By including the variability of the load in the cost function, it was possible to define the optimality criteria for the power flow of the storage. Numerical calculations have been performed obtaining the control strategies associated with the global minimum in energy costs, for a wide range of initial conditions of the system. The results of the calculations have been tested on a MATLAB/Simulink model of a rubber tyre gantry (RTG) crane equipped with a flywheel energy storage system (FESS) and subjected to a test cycle, which corresponds to the real operation of a crane in the Port of Felixstowe. The results of the model show increased energy savings and reduced peak power demand with respect to existing control strategies, indicating considerable potential savings for port operators in terms of energy and maintenance costs

Optimal Energy Management and MPC Strategies for Electrified RTG Cranes with Energy Storage Systems

This article presents a study of optimal control strategies for an energy storage system connected to a network of electrified Rubber Tyre Gantry (RTG) cranes. The study aims to design optimal control strategies for the power flows associated with the energy storage device, considering the highly volatile nature of RTG crane demand and difficulties in prediction. Deterministic optimal energy management controller and a Model Predictive Controller (MPC) are proposed as potentially suitable approaches to minimise the electric energy costs associated with the real-time electricity price and maximise the peak demand reduction, under given energy storage system parameters and network specifications. A specific case study is presented in to test the proposed optimal strategies and compares them to a set-point controller. The proposed models used in the study are validated using data collected from an instrumented RTG crane at the Port of Felixstowe, UK and are compared to a standard set-point controller. The results of the proposed control strategies show a significant reduction in the potential electricity costs and peak power demand from the RTG cranes

Power management system for RTG crane using fuzzy logic controller

In this research, there are two major objectives have been investigated for a Rubber Tyred Gantry (RTG) crane system: energy consumption reduction and decrease the stress on the primary source. These objectives can be met by using an advance control system that reads the status of the crane and outputs a power reference value which is fed to the storage device. This paper presents Fuzzy Logic Controller (FLC) approach to maximise the potential benefits of adding energy storage units to RTG cranes. In this work, FLC is described and simulated, with the results analysed to highlight the behaviour of the storage in association with the specific control system. An actual collected data at the Port of Felixstowe, UK has been used to develop the crane and ESS models and test the proposed control strategies in this paper. Furthermore, a comparison analysis between the FLC and the standard control system (PI) for RTG crane and ESS applications will be presented with respect to energy consumption, fuel saving and the control impact on the energy device. The simulation results of the FLC control strategy for the collected data shows that it successfully increases the energy savings by 32% and outperforms the PI controller by 26%

Financially Stimulating Local Economies by Exploiting Communities’ Microgrids: Power Trading and Hybrid Techno-Economic (HTE) Model

This paper thoroughly considers the potential of installing microgrids (MGs) in communities that suffer from the economic crisis in order to financially stimulate their local economies. Exploiting the state-of-the-art evolutions in the fields of the MG technology, the Hybrid Techno-Economic (HTE) model is proposed as a suitable techno-economic tool for assessing the power generation/consumption behaviour and the financial performance of these communities’ MGs.The contribution of this paper is four-fold. First, the HTE model is presented. HTE model describes a theoretical analysis that is suitable for studying community’s MGs. Appropriately concatenating one well-validated technical module and one new economic module, the HTE model quickly and conveniently reveals the power generation/consumption and economic profile of community’s MGs. Second, HTE model is integrated through an extended portfolio of power and financial metrics. The applied metrics study the influence of generation and consumption power changes on community’s MGs. The validity and the efficiency of the HTE model are examined with respect to these power changes while the impact of these changes on the power and cash flows of community’s MGs are assessed. Third, a cost-benefit analysis of the operation of community’s MGs accompanied with a financial stability analysis is also demonstrated. The main outcome of these analyses is the daily total benefit (TB) of community’s MGs with its respective financial bounds. Fourth, the contribution of the energy arbitrage and the power production mix among available power sources of community’s MGs to the daily TB is investigated.Apart from promoting the ecological awareness, this paper tries to become a catching argument for the communities in order to exploit the community’s MGs.Citation: Lazaropoulos, A. G., and Lazaropoulos, P. (2015). Financially Stimulating Local Economies by Exploiting Communities’ Microgrids: Power Trading and Hybrid Techno-Economic (HTE) Model. Trends in Renewable Energy, 1(3), 131-184. DOI: 10.17737/tre.2015.1.3.001

Optimal Design of Battery-Ultracapacitor Hybrid Source Light/Heavy Electrified Vehicle

This dissertation contributes to the optimal design of battery-ultracapacitor hybrid sources light/heavy duty electrified vehicle power-train architectures. Electrified vehicle (EV) in automotive technology is one of the major solutions to today’s environmental concerns such as air pollution and greenhouse effects. Light duty and heavy duty EVs can reduce the amount of the pollution effectively. Since, in this area all researches deal with optimal cost of the system and rarely consider the regenerate brake energy, the lack of comprehensive study on other important issues on optimal sizing including size, space, and acceleration time is feeling. Also it is necessary to be comparing with regenerate brake energy for battery and UC or both scenarios. Therefore the first part of this study consists of comprehensive optimization of a hybridized energy storage system including batteries and ultracapacitors considering a multi-objective function of cost, space, weight, and acceleration time. In motor drive part of the power-train, a study on analyzing current topologies is essential and if possible any new design which results in better efficiency and harmonics distortion would be appreciated. So in the nest part of this research which is the DC/AC motor drive, a novel motor drive with stacked matrix converter (SMC) was developed. This new design was compared with two other popular DC/AC inverters and was proved to be more efficient and an optimal match for the EV application. In the last phase of this research, since the DC/DC converter deals with battery/UC hybrid sources and their energy management systems (EMS), it needs to be fast enough that can improve the dynamics of the system, but so far, very rare studies have been done to improve the DC/DC converter dynamics in EV applications. Therefore the need of applying prediction algorithms to modify the controller of DC/DC converter dynamics is feeling. Therefore, three different prediction algorithms were developed to be used as the predictive controller for the DC/DC converter. Linear prediction as one of the fast and precise prediction algorithms were applied and modified

Integrated Li-Ion Ultracapacitor with Lead Acid Battery for Vehicular Start-Stop

Advancements in automobile manufacturing aim at improving the driving experience at every level possible. One improvement aspect is increasing gas efficiency via hybridization, which can be achieved by introducing a feature called start-stop. This feature automatically switches the internal combustion engine off when it idles and switches it back on when it is time to resume driving. This application has been proven to reduce the amount of gas consumption and emission of greenhouse effect gases in the atmosphere. However, the repeated cranking of the engine puts a large amount of stress on the lead acid battery required to perform the cranking, which effectively reduces its life span. This dissertation presents a hybrid energy storage system assembled from a lead acid battery and an ultracapacitor module connected in parallel. The Li-ion ultracapacitor was tested and modeled to predict its behavior when connected in a system requiring pulsed power such as the one proposed. Both test and simulation results show that the proposed hybrid design significantly reduces the cranking loading and stress on the battery. The ultracapacitor module can take the majority of the cranking current, effectively reducing the stress on the battery. The amount of cranking current provided by the ultracapacitor can be easily controlled via controlling the resistance of the cable connected directly between the ultracapacitor module and the car circuitry

Power Management of Remote Microgrids Considering Battery Lifetime

Currently, 20% (1.3 billion) of the world’s population still lacks access to electricity and many live in remote areas where connection to the grid is not economical or practical. Remote microgrids could be the solution to the problem because they are designed to provide power for small communities within clearly defined electrical boundaries. Reducing the cost of electricity for remote microgrids can help to increase access to electricity for populations in remote areas and developing countries. The integration of renewable energy and batteries in diesel based microgrids has shown to be effective in reducing fuel consumption. However, the operational cost remains high due to the low lifetime of batteries, which are heavily used to improve the system\u27s efficiency. In microgrid operation, a battery can act as a source to augment the generator or a load to ensure full load operation. In addition, a battery increases the utilization of PV by storing extra energy. However, the battery has a limited energy throughput. Therefore, it is required to provide a balance between fuel consumption and battery lifetime throughput in order to lower the cost of operation. This work presents a two-layer power management system for remote microgrids. The first layer is day ahead scheduling, where power set points of dispatchable resources were calculated. The second layer is real-time dispatch, where schedule set points from the first layer are accepted and resources are dispatched accordingly. A novel scheduling algorithm is proposed for a dispatch layer, which considers the battery lifetime in optimization and is expected to reduce the operational cost of the microgrid. This method is based on a goal programming approach which has the fuel and the battery wear cost as two objectives to achieve. The effectiveness of this method was evaluated through a simulation study of a PV-diesel hybrid microgrid using deterministic and stochastic approach of optimization