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The failure of power converters is currently the main reason of stopping for wind turbines. The unpredictable nature of wind power flow causes temperature swings to the semiconductor devices, which leads to additional thermal stresses and, eventually, unexpected failures. A suitable way to avoid this is using condition monitoring systems, which detect the degradation of the devices and reduce the...
This paper presents an innovative control law for permanent magnet synchronous motor (PMSM) drive for high dynamics applications. This kind of system (three-phase inverter connected with a PMSM) exhibits nonlinear behavior. Classically, to control the speed and the current (torque), a linearized technique is often used to study the stability and to select the controller parameters at specific operating...
Recently, the model based control has been successful applied for motion control applications. It improves better performance than a classic linear control. However, a model base control needs to know some parameters for exact estimations, here a load torque and stator resistance. In this paper, it presents three-observers for a differential flatness model based control approach for a DC permanent...
Traditional Modular Multilevel Converters (MMCs) need a special care to be taken for starting and for operation at low motor speeds in traction drives. Indeed, the low-frequency current may cause a significant unbalance between the converter sub-module capacitor voltages and then disturb the output waveforms. MMCs with the battery cells integrated inside the sub-modules are an alternative configuration...
The majority of electrical failures of wind turbines occur in the semiconductor devices of both grid and generator converters. This is due to the temperature swings caused by the variability of wind speed, which causes the progressive degradation of semiconductor devices. In order to increase reliability and decrease the operating costs, several condition monitoring methods have been proposed in the...
The lifetime estimation of power converters is a crucial issue for the reliability of electrical generators with renewable sources. During normal operations, the switching devices show junction temperature cycles that are widely recognized as the main cause of their failures. Although in-line junction temperature monitoring is extremely difficult, its knowledge is essential in order to achieve a reliable...
This study presents an energy management approach for a hybrid energy system comprised of a photovoltaic (PV) array and a polymer electrolyte membrane fuel cell (PEMFC). Two storage devices (a Li-ion battery module and a supercapacitor (SC) bank) are used in the proposed structure as a high-energy high-power density storage device. Multi-segment converters for the PV, FC, battery, and SC are proposed...
This paper presents a methodology to design the optimal capacitances and locations of stationary supercapacitors for light DC railways based on a single train simulator. The objective function of the optimisation problem takes into account the energy consumption of the substations and the total line energy loss. The problem includes an isoperimetric constraint to maintain to zero the net energy supplied...
The diffusion of distributed electric generation sources is a growing phenomenon, encouraged by the changes in the electric energy market and the concerns about gas emission. Microgrids are composed by different types of generators, several loads and power converters necessary to interface all the microgrid components and the microgrid itself with the main AC grid. This paper presents a new flexible...
The paper studies a three-phase PV power system connected to the LV power grid. The power system consists of a PV source, and a DC boost converter. The DC link is connected to the grid via a new cascade H-bridge converter, typical for modular multilevel converter application. A control approach is formulated. The control strategy aims at delivering to the grid the maximum power available from the...
The drive-train and power electronics are critical for the operation of industrial wind turbines. Faults developing in these components can result in long downtime and expensive repair costs, particularly when offshore wind farms are concerned. Effective condition monitoring (CM) of these components can result in significant savings for wind farm operators and contribute to a substantial improvement...
A modular multilevel converter based on MosFET half bridge modules has been recently proposed for the energy management and the drivetrain control of electric vehicles. This topology provides an active balancing of the cells in addition to the control of the propulsion motor, thus integrating into the same controller also the function of a battery management system. This paper analyses the possibilities...
In the recent years, there has been a considerable increment of diffused generators connected to distribution grids by means of power converters. These converters operate frequently below their rated power due to the fluctuation of the power generated by the renewable sources. In this scenario, power electronics interfaces could be also used as active harmonic compensators for other converters or...
The paper suggests a novel architecture of PV-powered Modular Multilevel Converter for building integrated photovoltaics. A grid-tied single-star configuration has been proposed. In particular, three different cell topologies have been analyzed and compared in terms of number of PV modules and rated voltages of semiconductor devices. Finally, a control strategy has been suggested in order to deliver...
New topologies of switching power converters could improve the efficiency of the energy conversion of battery electric vehicles, by achieving low cell unbalance and reduced harmonic content of the output currents. This article proposes a modular multi-cell converter with embedded cell balancing for battery electric vehicles. In this new topology, the series connection of the cell is obtained by means...
According to recent studies by 2020 a share of almost 12% of the worldwide electricity demand will be provided by the wind. Offshore wind farms are expected to have a significant growth to meet these targets, but higher procurement and operating costs are still limiting factors for their development. Several configurations based on internal DC collection have been proposed with the aim of reducing...
In this paper, we propose a new method for the accurate estimation of frequencies and magnitudes of harmonics and interharmonics caused on the supply-side currents by an adjustable-speed drive. The proposed method consists of a three-step procedure in which Estimation of Signal Parameters by Rotational Invariance Technique (ESPRIT) and Prony high-resolution methods are properly applied together with...
This paper deals with the parameter identification of supercapacitors used in industrial applications and in particular in hoisting systems. On the basis of a simple numeric procedure, it is possible to have a good estimation of the equivalent capacitance and resistance of supercapacitor modules. Experimental tests on a prototype crane validate the theoretical procedure. The results are compared with...
The paper deals with the control of onboard storage devices with supercapacitors for urban railway trains. The practical utilization of supercapacitors requires suitable power converters for the regulation of power flows between the catenary and the electrical drives of the power-train. These converters operate in DC current and have to be bi-directional in order to allow the charge and discharge...
Compliancy to grid codes has been a driving force behind the development of variable-speed technologies for wind generation. This resulted in the doubly-fed induction generator (DFIG) to become a common technology. The operational benefits of the DFIG derive from the possibility of controlling the operating speed of the generator from the rotor windings. Even if constructively different, the Dual-Excited...
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