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Nowadays, energy storage systems are playing an important role in several electrical applications. The modeling of these devices is very important, in particular, for electric vehicles, in order to understand and predict their behavior under different working conditions. Recently, the lithium-ion based solutions, and, in particular, lithium-ion capacitors (LiCs), are gaining a predominant position,...
The modern Distribution Systems (DS) require for accurate and fast Power Flow (PF) algorithms as a basis for other DS applications. Almost all decisions are taken based on accurate PF results and, possibly, they have to be taken in real time. In this paper, a new PF algorithm based on a linear programming approach is proposed. The graph theory is used for modeling the distribution network with some...
Energy storage systems are spreading both in stationary and transport applications. Among innovative storage devices, lithium ion capacitors (LiCs) are very interesting. They combine the advantages of both traditional electric double layer capacitors (EDLCs) and lithium ion batteries (LiBs). The behavior of this device is much more similar to ELDCs than to batteries. For this reason, several models...
A reliable and accurate estimation of the parameters of batteries equivalent models is of paramount importance in many applications. This paper is focused on electric vehicle framework. A simplified method for estimating these parameters is presented and validated. The proposed methodology introduces the concept of apparent state of discharge (ASOD), i.e., the traditional state of discharge adjusted...
Nowadays energy storage systems, such as batteries, are essential for electric vehicles and renewable energy sources. One of the important aspects is to model both the electrical and thermic battery behaviors. Another important aspect is to find a modeling procedure whereby the parameters of these models are found. In literature, different models and modeling procedures are present. This paper presents...
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...
This paper introduces a new control strategy to realize a virtual synchronous generator. The proposed control strategy is based on virtual impedance and band-pass damping algorithms to achieve the electro-mechanical characteristics of synchronous generator for the grid converter. Differences between new and traditional method on impedance emulation, and differences between traditional pure proportional...
This paper introduces the control of a photovoltaic (PV) interface converter ready to offer auxiliary service - reactive power control - that also has Phasor Measurement Unit capability. A prototype of the controller is implemented using a National Instruments Compact RIO and tested using Hardware In the Loop techniques. Experimental results demonstrate the converter functionalities.
In this paper, an algorithm for the estimation of the output voltage and current of an Inductive Power Transfer is presented. The algorithm is based on the use of a Kalman filter and only the measurement of the primary and secondary current is necessary to estimate the conditions at the secondary side of the system. The proposed algorithm can be utilized in a fault tolerant control for the recharge...
In recent years the use of batteries in parallel to photovoltaic generators are often proposed to increase the self-consumption of residential plants reducing the losses related to energy transfer to the grid. For PV stand-alone plants, the use of storage systems is necessary to ensure the feedings of the loads during night-time and when the sun is not enough to cover the power demand. The choice...
Electrochemical storage devices are spreading in many applications. Nevertheless, the data given by the manufacturers are often few and not homogenous. Using these data a correct sizing for a given application results very difficult and usually the designers makes a rough design in which the expected lifetime is not known and the costs are not optimized. This situation depends, mainly, on the lack...
Lithium-ion batteries are a key technology for current and future energy storage, whether they are used for mobile or stationary application. In particular, they play an important role for the electrification of mobility due to their high power and energy density and therefore their battery lifetime prediction is a fundamental aspect for successful market introduction. The ageing data provided by...
The work presents the feasibility study of an assembly-kit of a standalone DC solar refrigerator powered by PV energy, suitable for food conservation in rural villages with a specific focus on tropical-equatorial belt of Africa. The PV+refrigeration unit+controller is thought as a highly reliable, efficient, maintenance-free and durable package to be provided to the local users; the thermally-insulated...
The diffusion of grids generated by power electronic converters in which no rotating generators are present is growing day by day. In these grids, in case of fault, the maximum current is limited by the control of the converter. For this reason, traditional protections based on high current detection could fail. The risk of failure in fault detection is higher in single phase grids. In order to solve...
Because of the multiple power sources involved, fault protection is one of the most critical issues in micro-grids. If a micro-grid including a PV installation is connected to the grid by means of a front end converter, multiple possible cases of fault may occur. It is a typical feature of such configuration that, depending on fault resistance and location, fault currents from the AC grid may pass...
A solar panel or module, under different irradiation and temperature conditions, is characterized by its I-V characteristic curve. The evaluation of these curves allows to completely characterize the panel from the performance point of view. As well known, the performance of the photovoltaic (PV) system in terms of generated power depends not only on the photovoltaic panel quality but also on the...
The increase in installed power onboard ships and the adoption of electric propulsion led to the need of a rather complex power system. The so-called Integrated Power System (IPS) feeds all the ship loads, integrating into a single entity the functions of generation, regulation, distribution and utilization of the electric power. The integration, thus being a powerful tool to increase vessel's performance,...
This study presents innovative control algorithms for a hybrid energy system by a photovoltaic (PV) array and a polymer electrolyte membrane fuel cell (PEMFC). A single storage device, i.e., a Li-Ion battery module, is in the proposed structure. Linear proportional-integral (PI) and nonlinear flatness-based controllers for dc bus stabilization for power plants are compared. To verify the control algorithms,...
In recent years the interest for electric vehicles is strongly growing. Together with the spreading of private electric vehicles also public transports are using electric buses. Series hybrid buses are often a good choice for reducing pollution, consumptions and to allow short tracks in pure electric mode. In this paper a series hybrid electric bus is described. The bus, realized in the framework...
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...
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