1,721,001 research outputs found
Constrained Long-Horizon Direct Model Predictive Control for Grid-Connected Converters with LCL Filters
No full textThis paper presents a direct model predictive control algorithm for a three-level neutral point clamped converter connected to the grid via an LCL filter. The proposed controller simultaneously controls the grid and converter currents as well as the filter capacitor voltage, while meeting the relevant grid standards. Moreover, output constraints are included to ensure operation of the system within its safe operating limits. This is achieved by formulating the direct MPC problem as a constrained integer least-squares optimization problem, wherein the output constraints are mapped into input constraints. The presented results verify the effectiveness of the proposed method
Indirect Model Predictive Control for a Grid-Tied Three-Level Neutral Point Clamped Converter with an LCL Filter
No full textThe paper presents a model predictive control (MPC) algorithm for a three-level neutral point clamped converter connected to the grid via an LCL filter. The proposed long-horizon MPC, formulated as a multi-criterion quadratic program (QP), simultaneously controls the grid and converter current as well as the filter capacitor voltage, while meeting the relevant grid standards. To achieve the latter, a carrier-based pulse width modulation (CB-PWM) stage is employed. Finally, soft constraints are included to ensure operation of the system within its safe operating limits, particularly with regards to a potential overcurrent or overvoltage trip during transient operation. The presented results verify the effectiveness of the proposed method
Converter control strategies for the power flow management in a fuel-cell supplied vehicle for the public city transportation
No full textDue to the high costs, the fuel cell technology is likely to be applied firstly in the public electrically-propelled vehicles. In a prospective framework, the intrinsic slow response of a fuel cell stack to the load variation could be compensated by
conventional electrochemical batteries, which are in turn protected versus the short-time power pulses by super-capacitors. This paper presents a strategy for the power
allocation among the different sources, applied to a likely system configuration, and its implementation in a Matlab®–Simulink® model, taking into account the behaviour of all the electromechanical components. The simulations are executed both for a normalized drive cycle and for a more realistic urban running, in order to verify their effectiveness also in a randomly perturbed route
Design Aspects of Coils for EDS Levitation Systems
No full textEDS systems based on high frequency supplied windings are convenient candidates in standstill and low motion applications where strict mechanical tolerances are not practicable. In this paper a simple EDS system, based on a single levitation coil, is analyzed by an implementation of analytical formulations of the levitation force and of the vertical levitation stiffness. Such methodology can be effective for the parametric analysis to investigate the influence of the geometric sizes and to optimize the system performance taking into account the design constraints
Efficiency characterization for model predictive control of a three-phase voltage source converter
No full textVoltage Source Converters (VSC) are widely used in a lot of application field; consequently, their analysis and optimization, in terms of dynamic losses, is of primary importance. The availability of a reliable and accurate model is an important step to realize an efficient control strategy. This paper presents a losses model and an innovative control strategy, which integrates Model predictive control (MPC) theory and Feedback Quantizer Modulation (FBQM), minimizing the power converter losses
Control design aspects for an EDS levitation system
No full textEDS systems based on high frequency supplied windings are convenient candidates in standstill and low motion applications where strict mechanical tolerances are not practicable. In this paper a simple EDS system, based on a single levitation coil is presented. Images approach has been used to tune up a simplified model of the levitation coil in order to design levitation control. Simulations and preliminary experimental results are presented in order to validate the EDS system model and contro
A linear actuator supplied by inductive coupling in a moving coil transformer configuration
No full textMany applications require a high-dynamic short stroke linear actuator with a low mover inertia; at the same time the mechanical reliability represents a crucial factor for high frequency operation cycles. Under such circumstances, the supply feeding cables and the related cable tray may represent a weak point and a considerable load increase at the same time. The device presented in this paper doesn’t require any cable supply, since the power required by the moving windings is transferred via the electromagnetic coupling with a stator AC supplied primary winding
Sustainable MVDC Railway System Integrated with Renewable Energy Sources and EV Charging Station
No full textIn the last years, railway industry experts have been focused on the implementation of the smart grid concept and using renewable energy sources in electric railway systems (ERSs). In this paper, a model of future 9 kV MVDC ERS is proposed using MATLAB software integrating distributed energy sources and EV charging infrastructures. An algorithm is modified to accept real data from a physical railway system and simulate a digital twin (DT) based model. In this context, Rome-Florence high-speed railway line is considered as a real case study. An example modeling on the integration of wind turbines (WT), photovoltaic (PV), and EV charging infrastructures as auxiliary power supply to MVDC railway microgrid is presented with a modified power management system considering regenerative braking energy of trains
Wireless sensor nodes for freight trains condition monitoring based on geo-localized vibration measurements
No full textWhile rail freight transportation is gradually becoming a crucial asset in the context of decarbonization of the transport sector, new standards and requirements in this field aim at improving the safety and reliability of freight vehicles and the infrastructure. From this perspective, Condition Monitoring and Condition Based Maintenance are becoming essential tools to improve systems reliability through the use of in-service instrumented vehicles. On the contrary of high-speed applications, freight trains are actually not provided with any monitoring systems able to carry out this kind of analyses. In this context, an innovative hybrid monitoring system composed by wireless sensor nodes and a gateway was developed to be suitably mounted on a freight wagon. Sensor nodes, power supplied by solar energy, are able to carry out synthetic indices from vibration measurements, while the gateway acquires correlated GPS and odometry information. In order to take advantage of the acquired data, a software based on a geo-localization algorithm created for high-speed applications was developed in order to correlate vibration data to the railway line mileage. A field campaign allowed to test the system on a real freight wagon and to acquire many experimental data. Using the collected experimental data, in the paper is shown how the developed software can be used to perform diagnostic activities of the infrastructure. Moreover, it is demonstrated that relying on the only GPS information is sufficient to get enough accurate georeferenced data for freight trains applications. This paves the way to the future development of a completely wireless system able to perform condition monitoring of both the vehicle and the infrastructure minimizing the impact on the vehicle
Implementation of DC Micro Grid Tied PV-Storage Based EV Fast Charging Station
No full textInstalling new DC fast-charging stations especially alongside motorways is of great importance to meet the energy demand of a huge number of EVs in the near future. In this paper, a novel DC microgrid tied PV/storage system is purposed for EV fast chargers in which the power is supplied by large-scale PV arrays and storage systems through phase shift full bridge (PSFB) converter with minimum need of AC grid supplement. In this system, a phase shift full bridge (PSFB) is employed to boost the common voltage of the PV/storage system to higher values rather than connecting a large number of cells (PV and storage) in series to reach a high level of voltage which will consequently increase the reliability and redundancy of PV and storage system specifically for medium voltage (MV) DC grids. Moreover, the PSFB converter provides galvanic isolation between the storage and AC grid if there is a need to connect PV/storage system directly to the AC grid (without a line transformer). Due to uncertainties of solar irradiance generation, the power outputs of photovoltaic panels are not guaranteed which is the incentive to implement a storage system to certify adequate power supply to the DC fast charging station. Furthermore, the results are shown for a real 24-hour profile of solar irradiance and EV load. The performance of the system is evaluated in MATLAB/Simulink
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