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In this paper, a new pulse-width modulation technique is proposed for the output voltage control and the DC-bus capacitors voltage balancing of a Multi-Point Clamped multilevel converter. The voltage equalization is achieved by allowing each converter’s leg voltage to switch though multiple levels in a single modulation period (multi-step operation). The approach is generalized with respect to the number of levels and phases and can be applied regardless of the converter operating conditions. Nevertheless, the multi-step behaviour generally leads to an increase of the average switching transitions rate. In the proposed method, this drawback is mitigated with an online adaptive selection of the number of switching levels. The algorithm is validated through an extensive hardware-in-the-loop testing and compared to other approaches.

The paper deals with some new results on the averaging theory approach for the analysis of feedback controlled pulsewidth modulation power electronic converters. It develops some considerations regarding the averaging approximation of time-variant differential systems proving an analytical relationship between the accuracy with which the solution of the averaged model converges to the solution of the original time-variant model (i.e., the switched model) and the switching frequency of the converters. This relation is valid both for stable and unstable systems. Moreover, this paper confirms, as corollary, that under suitable conditions (verified during the standard operations of the power electronic converters) the averaged model uniformly converges to the switched model.

The full electric/hybrid electric propulsion is nowadays a promising technology for the aircraft. The problems related to the electric flight are inherent the storage system sizing, the design of lightweight motors and the power electronics converters. In this paper is proposed a preliminary study about the on-board wiring system. In particular, the maximum power transferrable with the common aeronautic wires in a distributed propulsion system has been investigated.

The Dual-Active-Bridge bidirectional dc-dc converter (DAB) is used more and more in many applications of power electronics (energy, automotive, aerospace, etc.) due to its advantages with respect to other topologies. Many linear controls have been proposed in literature. Because of the intrinsic non-linearity of the DAB, the linear controls do not offer great performances when the state vector changes between different equilibrium points moving through the whole set of possible values. In this paper, after a formulation of the DAB model, a Gain Scheduling control with minimum-norm pole-placement is proposed and discussed. The results show that it can guarantee accurate control in a wide range of operating conditions, thus improving both the stability and dynamic response of the system with respect to the linear controls while not presenting the implementation complexity of non-linear controls.

In this paper a Serie Series­Resonant Inductive Power Transfer (SS­RIPT) circuit for wireless e­bike battery charger is proposed. The system architecture is accurately described, while highlighting the main features of a suitable design procedure. A simulation model is developed in PSIM software to verify the circuit is fully functional. A full­scale proptotype of a 80 W battery charger has been realized, with particular attention to the layout optimization in order to minimize weight and volume of the final product. Moreover, it is equipped with two XBee­Pro S2 radios to also obtain a wi­fi communication between the primary and secondary side. Experimental tests carried out on the prototype confirm the effectiveness of the proposed design and control approach.

Wide band gap devices are inevitably the future of power electronic converters. However, their high switching speeds make the gate driver design a challenging task. In this way, parameterization of the gate driver resistors is critical to determine the slew rate and consequently the produced power loss and electromagnetic noise of the switch. To address these issues, in this paper, a post-prototyping multi-objective optimization method is introduced in order to parameterize the gate driver resistors. The method then is applied on a GaN-based half-bridge converter to reduce both power loss and electromagnetic noise. To evaluate the electromagnetic noise, near-field EMI of the GaN device is considered. Finally, the experimental results are provided to show the effectiveness of the method. Copyright © 2021 Praise Worthy Prize S.r.l.-. © 2021 Praise Worthy Prize S.r.l.-All rights reserved.

In this paper a 1.5 kW flux switching permanent magnet (FSPM) generator is presented for direct drive small scale wind turbine applications. For maximizing induced voltage and the output torque while minimizing cogging torque and unbalanced radial magnetic force (UMF), the proposed machine exhibits a new 6/19 stator pole/rotor teeth number and an outer rotor configuration. At first, in the paper an analytical design has been developed, then a finite element method (FEM) analysis is carried out for validating the analytical procedure and for design improvement. The simulation results extracted by FEM confirm the theoretical analysis procedure and help in the understanding of the performance analysis of the machine against the variations of the design variables. Furthermore, an experimental laboratory prototype of the proposed FSPM is implemented to confirm the analytical design and FEM modelling approaches. A comparison of induced voltage, torque, UMF and cogging torque produced by different FSPM configurations present in literature respect to the proposed generator has been developed. The results show the goodness of the adopted methodology and prove that, because of suitable electromagnetic performance of the proposed FSPM generator, it could be counted as a proper candidate for small scale wind turbine applications. Copyright © 2016 John Wiley & Sons, Ltd.

In this paper a new hybrid approach obtained combining a multi-objective particle swarm optimization and artificial neural network is proposed for the design optimization of a direct-drive permanent magnet flux switching generators for low power wind applications. The targets of the proposed multi-objective optimization are to reduce the costs and weight of the machine while maximizing the amplitude of the induced voltage as well as minimizing its total harmonic distortion. The permanent magnet width, the stator and rotor tooth width, the rotor teeth number and stator pole number of the machine define the search space for the optimization problem. Four supervised artificial neural networks are designed for modeling the complex relationships among the weight, the cost, the amplitude and the total harmonic distortion of the output voltage respect to the quantities of the search space. Finite element analysis is adopted to generate training dataset for the artificial neural networks. Finite element analysis based model is verified by experimental results with a 1.5 kW permanent magnet flux switching generator prototype suitable for renewable energy applications, having 6/19 stator poles/rotor teeth. Finally the effectiveness of the proposed hybrid procedure is compared with the results given by conventional multi-objective optimization algorithms. The obtained results show the soundness of the proposed multi objective optimization technique and its feasibility to be adopted as suitable methodology for optimal design of permanent magnet flux switching generator for wind application.

In this paper a battery energy storage system (BESS) for single-phase residential application is proposed. The idea is to apply Gallium Nitride (GaN) devices in order to achieve the advantage of very low switching power loss and relatively high efficiency. The GaN-based BESS includes a bidirectional half-bridge dc-dc converter and a full-bridge single-phase grid-connected inverter with paralleled GaN devices. The power stage design, GaN paralleling, and controller design are analyzed. Moreover, OrCAD Spice and MATLAB SIMULINK simulation results are discussed and validated.

The dual active bridge bidirectional dc-dc converter (DAB) is a topology that is gaining increasing interest in many areas of power electronics (aerospace, automotive, energy, etc.) for its many advantages and its ease of control. For this reason many variants of DAB converter have been proposed and many control algorithms are present in the literature. In the paper a new non-linear control based on model-reference adaptive approach (MRAC) is introduced. In the paper after a full dynamic formulation of the converter, MRAC control algorithm is proposed together with its stability and convergence analysis. The performances of the suggested algorithm have been verified with different simulations on a 3kW DAB converter. The results prove an excellent dynamic response of the controlled system even in the presence of strong parametric variations and disturbances.

Summary Compared with different types of renewable energies, wind energy has the fastest annual growing rate over the last decade. Hence, employing a framework based on numerical algorithms for optimal design of electrical generator, especially adopted for wind power systems, is a great challenge in electrical systems. Recently, for their rigid structure, high torque density and lower mass of the flux-switching permanent magnet (FSPM) generators have attracted much interest because they are capable of supplementing conventional permanent magnet synchronous generators. In this paper, a new analytical hierarchy process (AHP) approach is proposed for a multi-objective optimization of the design of the FSPM generator. To carry out the optimization, trade-offs are considered among more conflicting targets (cost, mass, and some electromagnetic performance). Finite element method numerical results, experimentally validated by means of a prototype, have been used to assess the required data for the optimization. Then the optimal solutions given by the AHP method have been compared with the solutions obtained using different classical optimization methods. The results showed that the AHP approach gives the best solution with respect to the earlier designs and also with respect to other conventional optimization methods, confirming its effectiveness to be used in the optimal design of electrical machines. Copyright © 2015 John Wiley & Sons, Ltd.

The paper presents a generalized averaged model and a reduced-order averaged model of a dual active bridge bidirectional dc-dc converter, taking into account parasitic components. On the basis of these models, a particular non-linear voltage control scheme is suggested using an integral sliding mode control approach for driving the adopted single phase shift modulation technique. The main operative conditions of the converter have been examined through extensive simulations. The numerical results confirm the effectiveness of the proposed strategy. The suggested control exhibits a strong robustness against parameters variations and disturbances and presents a very simple implementation.

Nowadays, the quickest developing rate among all kinds of renewable energy generation belongs to wind power industry. Hence, proposing an optimization framework to achieve the best design of wind power conversion system, especially wind electrical generator is required more than ever. Recently, flux switching permanent magnet (FSPM) generators that are well known for rigid structure, high torque density and lower weight have attracted high attention where these features bring more ability respect to permanent magnet synchronous (PMS) generator. In this paper a thorough analysis is carried out to find an optimal design of FSPM generator by interrogating the possibility to employ different structures for small scale wind conversion systems. To achieve this purpose, a precise challenge is laid down in investigation of various design characteristics. Hence, a multiobjective function depending on mass, cost, volume and electromagnetic performance of the generator is taken into account. In the sequel, considering multi attribute decision making (MADM) techniques, a framework based on an improved analytical hierarchy process (AHP) composed by a hybrid scheme formed by artificial neural network (ANN) and classical AHP is proposed to achieve trade-off design of the FSPM. A numerical study has been implemented on different test cases to assess the performance of the proposed framework. The obtained results prove the goodness of the proposed technique and suggest interesting solutions for the considered applications.

In the paper a new discrete-time integral sliding mode control (DISMC) with disturbances compensation and reduced chattering for grid-connected inverter is proposed for active and reactive power regulation. Differently by many SMC proposed in literature that have a time-continuous formulation in spite have been implemented with digital processor, the proposed DISMC is fully formulated in discrete-time, taking into account the effects introduced by a microprocessor-based implementation. As will be demonstrated such approach consents to reduce the chattering about the sliding manifold within a boundary layer of O(T2) thickness instead of O(T) (being T the sampling period of the control algorithm). Moreover it introduces a correction of the control vector which eliminates the influence of modeling error and external disturbances improving stability and robustness of the controlled system. Constant converter switching frequency is achieved by using space vector modulation, which eases the design of the ac harmonic filter. In the paper, after a detailed formalization of the proposed control algorithm, several numerical and experimental results on a three-phase grid-connected inverter prototype are shown, proving the effectiveness of the control strategy. K e y w o r d s: sliding mode control, grid-connected inverter, renewable energy, PV inverter

In the paper a new discrete-time integral variable structure control of grid-connected PV inverter is proposed in order to maximize the input power given by PV arrays and at the same time for using the grid-inverter as a reactive power compensator. In the last years different variable structure controls (VSC) have been proposed in literature. In spite these algorithms have been implemented on digital hardware, they have been developed by means of a timecontinuous formulation neglecting the effects of a microprocessor-based implementation. Such approach can cause an increasing amplitude chatter of the state trajectories which means instability. The proposed VSC is fully formulated in discrete-time, taking into account the effects introduced by a microprocessor-based implementation. Moreover it introduces respect to the classical formalization of the VSC an integral action that improve the performance of the controlled system. After a detailed formalization of the proposed control algorithm, several numerical and experimental results on a three-phase grid-connected inverter prototype are shown, proving the effectiveness of the control strategy. Thanks to the proposed control law the controlled system exhibits fast dynamic response, strong robustness for modelling error and good current harmonic rejection.

The progressive deregulamentation of the electrical energy market, together with the incentive to use zero emission energy sources, can encourage, in the middle term, the diffusion of generation sites dispersed on the territory. The utilization of cogeneration in civil and industrial installation and the technological progress associated to small and medium size systems involve increasing requests of linking to the LV and MV distribution grid, which modifies itself from “passive” to “active”. Fuel Cell based electrical distributed sources, suitable to feed also thermal requirements, make the distribution utilities able to satisfy the customer requirements in terms of electrical and thermal loads, creating the opportunities to reconfigure the relation among producer, distributor and customer. The paper focuses on the performances of fuel cell sources and on their integration in the distribution networks, examining the benefits that fuel cell sources could determine on system potentialities in terms of technical and reliability aspects.

In this paper, a numerical tool is presented in the field of the computation of electrical unknown of an electrical machine, very suitable to solve non-symmetrical condition too by means of a very friendly computer evaluation. This software tool, written in MATLAB language, bases itself on a formulation of air-gap field distribution by means of the linear combinations of the most elementary components of m.m.f (in case of windings) or of flux density (in case of permanent magnets) called Window functions. Differently from the standard methods, that allow appreciable results only after laborious calculations and complicate mathematical approaches that consent to formulate the problem in convenient domain, the proposed technique approaches and solves any problem directly in the time domain. The other most important feature of this procedure is its easy implementation into a proper tool that allows a friendly utilisation both by non expert people and by specialists in design phase activity or during the computation of performances in transient operations or in test conditions. In the paper, this tool is proposed in order to solve three cases of electrical machines simulations: the results demonstrate the interesting performance of the proposed tool.

In the paper the authors proposes a Second-Order Super-Twisting Integral Sliding Mode Control for a Grid-connected Double-Stage AC-DC/DC-AC Power Converter (DSACPC) of a renewable electrical energy system. The DSACPC consists of a Permanent Magnet Synchronous Generator (PMSG) directly connected to the renewable electric source, a generator-side controlled rectifier and a grid-side inverter. The proposed control strategy applied both to two stages is able to maximize the extracted energy from the renewable source, while to regulate the DC-link voltage and to achieve unity power factor and low distortion currents. The employed control strategy can regulate both the reactive and active power given to the utility grid independently and consents to the system to be enclosed in a smart-grid thanks to its performance. In fact the system giving the desired active power to the grid can be used also as a reactive power compensator in grid balanced conditions or as a system of current harmonic rejection in the case of unbalanced conditions of the grid. For the formulation of the control a sliding-Mode Observer is designed. Simulations and experimental results prove the high efficiency and high performance of the full proposed control system.

In the paper an interleaved soft switching dc-dc converter for applications in electric vehicle is proposed. The used topology raises the efficiency and the power density of the dc/dc converter minimizing switching losses by adopting a simple auxiliary active clamping circuit. Such auxiliary circuit is operational regardless of boost or buck mode of operation. The configuration guarantees fixed switching frequency, active clamped zero voltage switching operations of the main switches and bidirectional power flow. ZVS operations are guaranteed with wide load range. In the paper the operating principle, soft-switching conditions and steady state analysis are presented. A 27 kW prototype is designed and simulation results to verify the theoretical analysis are provided.

The paper deals with a new energy management strategy for pure electric vehicles (PEV) with dual energy storage systems (battery and ultracapacitor). The proposed strategy is able to split the power demand between battery and ultracapacitor maximizing the driving range and the performances of the vehicle and increasing the life cycle of the battery. To accomplish load sharing an energetic model of the PEV is formulated and an optimal control problem with inequality constraints is resolved using the particle swarm optimization technique (PSO) to search the global near-optimum at each sample interval. Different types of batteries (Lead-acid, NiMH and Li-ion) have been considered alternatively togheter with the supercapacitor. The results show that the proposed strategy guarantees energy saving and assures failsafe operations for the battery unaffecting the drivability of the vehicle.

The paper presents the activities ongoing in the framework of a two-year Italian National Research Project aimed at developing a distributed Driving and Steering (DaS) system for Electric Vehicles (EVs). The system is built up around an actuation module embedding a rotary-linear motor and including a power converter and a local Electronic Control Unit (ECU) to supply and control the motor. The actuation module is intended to make a wheel active so as to give it propelling and steering capabilities. The DaS system, in turn, includes a central ECU and a fieldbus to govern and network the system, and a power supply stage. The Project under consideration is focused on a DaS system with two active wheels for a light-duty EV.

The hybrid electric and electric vehicles in the next future will be employed more and more. Many considerations induce to this solution: the efficiency of these vehicles, greater than the conventional ones, the major benefits that they offer in terms of environmental pollution, the increasing costs of the petroleum and its instable market. A key component of each electric and hybrid electric vehicle is the energy storage system. It plays a prominent role on the performances and on the overall drive efficiency of the vehicles, therefore from some years the study of this subsystem has recalled a strong interest among the scientists, the automakers and the manufacturers of energy storage systems. Recently, the main auto industries have found join-ventures with the manufacturers of batteries, supercapacitors and flywheels in order to study and to produce advanced energy storage systems for electric and hybrid electric cars and many innovations are introduced in this field (i.e. lead-carbon battery, bi-polar lead acid battery, thin film metal battery, supercabattery, Li-poly and so on). All these attentions justify the aim of this paper that is to illustrate a comprehensive state of the art on the main energy storage systems suitable for electric and hybrid electric vehicles, introducing also the most recent innovations on this important subsystem and the next goals to earn.

In the paper a method, for the evaluation of the main electric and magnetic quantities in electrical machines, is proposed. This technique, approaches and solves any problem directly in the time domain.

The paper deals with a voltage feeding algorithm for a linear induction drive that takes into account the end-effect and the actual distribution of the windings. It realises a decoupled control of the thrust and of the magnetising condition of the machine. In order to take into account the end effect, different space harmonics of the flux density distribution must be considered. For this reason a suitable state observer has been adopted. The considered observer is arranged as a diagonal system of linear differential equations, therefore it gives a fast evaluation of the estimated quantities. The reference currents computed according to the field oriented strategy, are used by the feeding algorithm in order to evaluate, at each sampling interval, the reference vector of the supply voltage. This vector is adequately modulated by means of the vector PWM.

The paper deals with a new ZVS (zero voltage switching) half-bridge current-fed DC-DC converter for fuel-cell based inverter system suitable to be coupled with fuel-cells sources. The spreading of fuel-cells has impelled a deep study of DC/DC converter structures properly designed to solve problems connected with the use of fuel cells as primary energy source. A good solution is represented by half-bridge current-fed DC-DC converter. The paper focuses on this kind of converter proposing a modification of the base structure in order to achieve ZVS operation. Moreover, in the paper, a full analysis of the proposed structure is presented and SABER numerical results are shown and compared with results obtained with an hard-switch half-bridge current-fed DC-DC converter. The results prove the very good performance of the suggested solution.

The steady-state behaviour of an induction machine with a symmetric rotor cage and a faulty asymmetric stator is analyzed. The asymmetric machine is modeled by means of the space vector approach. The winding asymmetry is taken into account by considering each conductor of every single slot separately. Harmonic components of the permeance produced by the rotor slots are taken into account too. Harmonic slotting components of stator currents have been computed for different faulty machines affected by short circuits with different values of the dimensions of the rotor slots, different numbers of the rotor bars and different pole-pairs.

Ac motor drives are experiencing and exciting new impact in the industrial automation applications as well as in research studies. Inherent advantages of adjustable frequency operations could not be fully exploited without adopting a suitable control strategy. The paper gives a fully digitalised direct torque control algorithm for induction motor drives using a state feedback control of the motor. The goal of the control strategy consists in achieving a very fast response of the torque control loop and a poor parametric sensitivity. The proposed feeding algorithm has been called “direct”, because links directly armature feeding voltages to reference value of the electromagnetic torque and to reference value of the flux. In the paper the suggested control strategy is presented and the dynamic performances of induction motor drive are analysed. The control technique seems to be a good compromise between accuracy and easy handling of the control algorithm. The results shown the good dynamic performances of the system and the feasibility of a microprocessorised implementation of the feeding algorithm on high performance evaluation board, in order to realise a real-time control.

In the paper two control techniques are compared with respect to the traditional field oriented approach (FO), in order to define the range of applicability of each one. Targets of the different controls are to achieve a vector control and to generate firing commands for the quasi resonant inverter (QRI), that guarantee soft switching of the inverter switch, improving the dynamic response of the whole system. These targets are obtained by means of a state feedback approach.

The paper presents a comparison among different current control techniques for active power filter. The fixed-frequency hysteresis controller, the predictive controller and the neural controller are considered and different performance, achieved by the three controls, in a typical active power filter application are shown and discussed. The paper presents a comparison among different current control techniques for active power filter. The fixed-frequency hysteresis controller, the predictive controller and the neural controller are considered and different performance, achieved by the three controls, in a typical active power filter application are shown and discussed. The paper presents a comparison among different current control techniques for active power filter. The fixed-frequency hysteresis controller, the predictive controller and the neural controller are considered and different performance, achieved by the three controls, in a typical active power filter application are shown and discussed. The paper presents a comparison among different current control techniques for active power filter. The fixed-frequency hysteresis controller, the predictive controller and the neural controller are considered and different performance, achieved by the three controls, in a typical active power filter application are shown and discussed.

The paper focuses on an energy management strategy for an electric vehicles powered with three power sources (PEM fuel cells, LiFePO4 battery and supercapacitors). The aim of the proposed strategy is to split the power demand between the different sources maximizing the driving range and the performances of the vehicle and increasing the life cycle of the battery and of the PEM fuel cell. To accomplish load sharing an energetic model of the overall system based on experimentally validated models of the PEM Fuel Cell, LiFePO4 battery and supercapacitors is formulated and an optimal control problem with inequality constraints is resolved using the particle swarm optimization technique (PSO) to search the global near-optimum at each sample interval. The results show that the proposed strategy guarantees energy saving and assures failsafe operations for the battery and the PEM Fuel Cell unaffecting the drivability of the vehicle and increasing autonomy.

In the paper two control techniques are compared with respect to the traditional field oriented approach (FO), in order to define the range of applicability of each one. Targets of the different controls are to achieve a vector control and to generate firing commands for the quasi resonant inverter (QRI), that guarantee soft switching of the inverter switch, improving the dynamic response of the whole system. These targets are obtained by means of a state feedback approach

The paper presents a further tool of software MADES (Machine Analysis DESign) oriented to no specialist operators in the field of design and analysis of linear induction machines (LIMs). In particular the presented version has been oriented to the analysis of a LIMs in one and two dimensional approach. The really advantage of this tool can be carried out especially in un-balanced feeding conditions and in absence of standard geometrical, electrical or magnetic symmetry.

The paper deals with a dynamic improving response of an induction motor drive. Targets of the control are to impose a desired cinematic trajectory to the system, to achieve a fast torque response and to have a poor parametric sensitivity. These targets will be achieved by means of a particular state feedback approach that has interesting advantage respect to the classical one in terms of short computation time, together with a good accuracy of the results.

The behavior of a single-sided linear induction machine (LIM) with short-circuited turns in the primary winding was analyzed using a modified one-dimensional model which considers the end-effects and real winding distribution. Input currents and the motor speed were used as process variables. Due to the end-effects, the negative sequence component of the currents is load-dependent and does not provide a suitable representation of the diagnostic index. The amplitude of the vector ΔĪp = Īp-Īp0 can be used as a diagnostic index since it is correlated with the fault percentage and independently from the load.

The paper revisits some mathematical models of induction linear motor by the point of view of the control purposes. The results of different mathematical models used for the analysis of a double side linear induction motor are compared. All the adopted procedures are formulated by means of space vector theory and take into account, with different simplificative hypotheses, the end - effects and the real distribution of the primary windings. The edge effects are always neglected. The aim is the analysis of the different methods in order to achieve a good compromise between a sufficient accuracy of the results and a fast response, necessary when the model is used in a real time control system. After a theoretic analysis of the adopted models a comparison among different formulations is developed and a set of simulations are presented and discussed.

In this paper, the performance of a vector control algorithm, applied to a linear induction motor (LIM), has been investigated. Specifically, the authors' interest is to verify the possibility to control, independently, the thrust and flux density of a LIM, by means of two MMF components and to test the sensitivity of response with respect to these quantities. >

A novel modulation technique suitable for the current control of brushless DC drives under commutation is presented in the paper. The pulse width of the chain voltages are determined by means of a predictive algorithm under the constraints of minimum Joule losses and torque ripple free commutation. At maximum speed the torque ripple appears but is lower than that of six step operation. The proposed technique leads also to higher mean torque than that of traditional six step operation. Simulation results highlight the better performance of the drive controlled by the propose algorithm with respect to that of the traditionally controlled drive.

The paper focuses on the performances of a PV source based electrical system. On the basis of technical and economic analyses, a traditional PV system, equipped with a battery of electrochemical accumulators, is compared with a hybrid system provided by fuel cell and electrochemical capacitor sources. In particular, the operating opportunities are examined and the reference indexes are compared in terms of performances, reliability and cost. Finally, through the Life Cycle Cost methodology and the definition of an economic index, assessments of the systems are expressed with reference to the Energy Not Supply (ENS) value, in order to define a useful tool for system design.