L. P. Di Noia

A PV plant simulator for testing MPPT techniques

This paper introduces a versatile and reliable photovoltaic systems simulator. It includes the main components of a photovoltaic plant: a PV string and a PWM controlled boost chooper. The key feature of this simulator is the ability to consider different and non-uniform irradiation and temperature conditions (partial shading and partial heating of the strings). All the different I-V and P-V or P-I characteristics can then be determined in such non-uniform irradiation and temperature conditions, with the aim to try different MPPT algorithms. The simulator also allows to verify an enhanced version of the Incremental Conductance algorithm (IncCond) where, in order to reach the real absolute maximum power condition, the reference control current of the boost chopper are periodically reset to a given percentage of the short circuit current at standard conditions. After this perturbation, the steady state power values are registered and compared to establish the final value of reference current that allows the IncCond algorithm to reach a steady state at the real abolute maximum power transfer.

The application of Bayes inference in multicriteria analysis to design energy storage systems in renewable power generation

In recent years, the wide utilization of renewable energy sources has brought some problems for the dispatching of generated energy. In recent technical papers are proposed some solutions to improve the renewable energy dispatching: i. e. it is possible to set up an optimal strategy to recharge electric vehicles, or use batteries storage systems, supercapacitors or fuel cells. The aim of this papers is the application of multicriteria analysis to design batteries energy storage systems. By means of Bayesian inference is possible to take into account some uncertainties of batteries characteristics and estimate the best choice for the design of the storage system.

Design of a PMSM for the electric steering of the nose landing gear

This paper is focused on the design of a PMSM for the electric steering of a nose landing gear. The traditional hydraulic steering systems utilized in a nose landing gear are usually based on a rack and pinion solution with two hydraulic pistons at the external sides. The main idea proposed in the paper is the substitution of the hydraulic steering system with an electric steering system based on the coupling between an harmonic drive and a three phase double rotor axial flux permanent magnet machine fed by two different three phase inverter.

An advanced system for power supply and power quality improvement of isolated AC passive network

The paper presents an advanced solution for power supply and power quality improvement of isolated AC passive networks. The embedded system consists of a Self-Excited Induction Generator (SEIG) and a Static Var Compensator (SVC) specifically designed for the considered application domain. The SVC is composed by two legs and with an LC filter is linked to the three phase passive network. A proper SVC control strategy is devised and applied on a test system in order to verify its effectiveness in:(i) enhancing power quality, (ii) improving the power system stability as whole, (iii) minimizing the effects of unbalanced loads.

Energy management optimization within the Electric Mobility system

Electric Mobility can produce a considerable impact on the rational use of energy through the appropriate design and management of the Grid - Vehicle system. Starting from the fact that electricity is the most effective vector for transferring the energy from “well to wheel” in terms of efficiency and environmental quality conservation, with the European mix of primary energy sources used for electricity production.

Design considerations on energy storage system for electric aircraft propulsion

The growth of electric aircraft propulsion systems requires an accurate design of the battery energy storage system (BESS) and of the electric motor involved in the propulsion unit. The motor performance can be strictly linked to the characteristic of the BESS and to the variation of its parameters, as the output voltage. In this paper some design considerations are discussed with reference to the on-board BESS and to the choice of parameters of permanent magnet synchronous motors used in full electric aircraft propulsion. In particular, the problem is approached considering a speed and power profile of a realistic mission of a commercial small power twin engine four-seat aircraft. Some numerical investigations are carried out with the aim to compare performance achievable by the electric propulsion system in correspondence of different sizes and configurations of the batteries.

A direct drive solution for contra-rotating propellers in electric unmanned aerial vehicle

In this paper a solution is proposed for contra-rotating propellers in electric unmanned aerial vehicles. It is based on a direct drive system where the contra-rotating blades are directly fixed on the rotors of an axial-flux permanent magnet motor. The latter one is constituted by two external rotors and a single internal stator divided in two different sides. The study is focused on a 6 slots-4 poles three-phase motor and on a 10 slots-4 poles five-phase motor, characterized by single-layer armature windings. For each motor configuration some sets of motor sizes are found by using an automatic calculus procedure and by imposing suitable electrical, thermal and mechanical constraints.

A control strategy of a stand alone induction generator coupled with a diesel engine for distributed generation with renewable sources

The paper presents a new control strategy for an induction generator coupled with a power reactive compensator. The test system consists of a diesel engine, an induction generator, an inverter and a variable load (three-phase and single-phase loads). The paper focuses on the composite control of the inverter dc-link and prime mover in order to improve the dynamic assessment of the induction generator. The control strategy is based upon the decoupling of the regulating actions, this allowing to conceive a control structure quite similar to the classical active and reactive modulations of electrical power systems. The inverter frequency is opportunely changed to improve the dynamic behavior of the whole system. The control acts on the torque of the diesel engine and on the instantaneous frequency of the inverter. The results of numerical simulation confirm the goodness of the proposed control.

Stator current signature analysis for fault diagnosis in permanent magnet synchronous wind generators

Inter-turn short circuit faults are the most common stator winding faults in permanent magnet wind generators. Their early detection is vital to avoid subsequent damages which can led to catastrophic machine failures. To accomplish this task stator current signature analysis has been recently proposed for identifying inter-turn faults via a non-invasive, non-destructive and cost effective approach. Since no best stator current signature analysis approach is recognized as optimal, the paper takes in consideration the one able to offer the minimum severity degree which is Hilbert Huang Transform. To propose some improvements of the latter in stator current signature analysis, a real 60 kW-25 rpm permanent magnet wind generator is firstly designed via finite element based approach in FLUX® environment. Then SCSA in faulty conditions is performed via proprietary software highlighting how the introduced modifications could further enhance the signal processing algorithm performance.

Stochastic modelling of electrochemical batteries for smart grids applications

A stochastic modelling of electrochemical battery for their lifetime assessment is proposed and numerically evaluated in smart grids context. The method uses a proper battery model, characterized by stochastic current demand, for deducing the battery lifetime. In particular, a stochastic process for describing the current load is adopted, which is namely described by a proper Poisson stochastic process, appearing suitable to describe random smart grid operations. Extensive numerical experiments have been performed by means of this battery model, in order to fit a proper reliability model to numerical lifetime data. Extensive numerical simulations have been performed by adopting, as model parameter values, those obtained after numerous laboratory tests. Hence, it is shown that the Inverse Gaussian model is the best fitting reliability model.