This paper introduces a Reluctance Equivalent (RE) EMF model for sensorless position estimation of synchronous reluctance motors (SynRMs). The unique salient structure of the SynRM results in varying reluctance paths associated with the stator phases. These variations in reluctance cause continuous changes in phase inductance relative to the rotor position, leading to the generation of RE EMF in the stator phase. The RE EMF model is initially analyzed in the abc plane and subsequently transformed into the stationary αβ plane for position estimation. The model’s validity is demonstrated using a Finite Element Model of the developed SynRM prototype

Electric Vehicles (EVs) are gaining importance in many countries in the world as they are clean and cheap mode of transportation. The main issue with EVs is the charging time. Among many methods, pulse charging is one of the methods used for fast charging of Electric Vehicles. To overcome the issue of poor power factor on the source side introduced by diode bridge rectifier, a Power Factor Correction (PFC) circuit is used. The current in the inductor of PFC circuit and the voltage of its capacitor is controlled appropriately to ensure required performance. Conventional control methods in addition with pulsed charging leads to voltage swell and swell at the DC bus due to the presence of multiple energy storage elements. This paper suggests a Modified Control Scheme for PFC circuit to overcome the problem of voltage variation and keep the DC bus voltage variation within a tolerable limit.

Wireless power transfer (WPT) is a well-known technique for electric vehicle (EV) charging. In this context, the power transfer profile is the key factor especially for the dynamic wireless power transfer (DWPT), where the time of magnetically coupling between track and pickup coils is significantly less. In this regard, this paper has proposed a three-element compensation network (3ECN) capable to transfer nominal power in the large portion of coupling, in other words, nominal power transfer is possible in the considerably large interval of mutual inductance. The paper has also included 1ECN and 2ECN and moved to 3ECN with a proper description of every CN and step-wise consideration and evolvement based on supply voltage limit, power transfer limit, and supply current limit. Simulation has been carried out in the MATLAB simulation environment considering the fundamental theory.

Limited on-board available charge is one of the most important concerns in the wide acceptance of Electric Vehicles (EVs). EVs can be charged either at home or at charging stations. Another solution that appears promising is wireless charging while in motion to extend the range of a vehicle. Concern in this case is availability of the charging infrastructure all along the high-way. There is always a possibility that even though vehicle is enabled for wireless charging, the source system is not available. Under such a situation, an on-board wireless charging system with bi-directional power flow capability can be useful for vehicle to vehicle (V2V) energy exchange. Present paper considers the case of bidirectional V2V energy exchange system. At first such a system is explained and then discussion is extended to the sizing of coil system, circuital arrangements and explanation of different modes of energy exchange. Operation of the system is explained with the help of simulation results to justify the possibility.

Space vector pulse width modulation (SVPWM) technology is widely used in power converters as a modulation strategy that can effectively improve voltage utilization and reduce harmonics. However, as the number of levels increases, the number of space vectors suddenly increases, and the modulation algorithm design and implementation become more and more difficult. As a result, such application is hardly seen in three-phase multilevel current source rectifier (MCSR). This paper proposes a basic theory and control algorithm of SVPWM technology applied in 7-level rectifiers, which adopts a double closed-loop control strategy for inner current loop and outer voltage loop. System modeling and theoretical analysis with detailed vector selection method of the proposed control are provided. Simulation results show that both unit power factor and 7-level waveforms have been achieved, which has validated the proposed control.

Battery-powered Electric Vehicles (EVs) are considered as an effective solution to curb carbon emissions and fight global warming. One of the main drawbacks in driving an EV is range anxiety, which can be defined as the fear of vehicle having insufficient range to reach its destination due to lack of charging. Vehicle-to-vehicle (V2V) charging is being explored as a solution to mitigate the range anxiety issue. V2V charging allows the sharing of charge between two EVs so that if an EV is stranded far from a charging station, it can be charged from another EV. Various V2V chargers have been studied. It has been found that the traditional chargers involve many power conversion stages, which reduces the efficiency in the energy exchange. In this paper, an off-board DC V2V charger is presented. It reduces the power conversion stages while dispensing with the use of any on-board charger. To implement the off-board DC V2V charger, a bidirectional DC-DC converter is adopted. The converter operates in various modes, depending upon voltage and state of charge of the EV batteries. In turn, the V2V charging is managed in an automatic way. Operation modes and management program of the off-board V2V charger are discussed in the paper.

DD coils are often selected as case study for the research activity about the dynamic wireless charging systems for electric vehicles and are proposed to setup the track and/or the pickup onboard the vehicles. Indeed, they offer good coupling performance, but their capability can be fully exploited only if both the track coil and the pickup have the same DD topology, otherwise the transferred power decreases substantially. This paper proposes to use a three-legs inverter to separately supply the two sub coils that form a DD coil. Adopting a suitable control strategy of the inverter, the dynamic wireless charging system is made able to perform an effective power transfer both to DD coil pickups and to spiral coil pickups. Condition under which this result is achieved and the required modifications of the supply system and of the coils are studied in the paper. The proposed solution is validated by means of simulations.

The paper is concerned with the wireless power (WP) systems feeding in-motion electric vehicles (EVs) and focuses on the power sizing of three key WP system components, namely the track coils, the pickup and the voltage supply. It is assumed that the track is made of lumped type with no overlapped coupling of the pickup, and that the track coils and the pickup are compensated for by series resonating capacitors. Power sizing equations are formulated for a WP system that is controlled in the way of transferring a constant power to EVs during their motion over a large part of the track coils. Due to the variation of the coupling between the pickup and a track coil, the transfer of a constant power requires the adjustment of the currents in the WP system, obtained by commanding the embedded power conversion units. Two solutions are examined: by one solution, the pickup side current is controlled at a proper value whilst the track side current is regulated at a constant level; by the other solution, the opposite occurs. Power sizing equations are expressed in terms of specifications and parameters of the WP system. The equations outline that the power sizing is higher for the components in the side where the current control is executed. At last, the case study of a WP system is examined, showing the convenience of the track-side control.

Dynamic WPT systems are extensively investigated as a promising solution to the issues of the comparatively short range and long recharge time of the electric vehicles. In dynamic WPT systems, the lumped tracks exhibit greater power transfer efficiency than the stretched ones but require the supply of a large number of transmitting coils. This paper proposes a command strategy for a dual-output inverter that allows the concurrent supply of two track coils, with the ability of adjusting independently the voltage applied to each of them without altering the phase relation between the two supply currents. Moreover, if the series resonant compensation is used at the track side, the proposed strategy is robust against the onset of a reactive component in the loads seen at the inverter outputs as it inherently corrects the phase of the coil currents without making recourse to any additional control algorithm.

In the last years, Renewable Energy Sources (RESs) have increasingly contributed to the power delivered by the grid. Despite the environmental benefits made by RESs, their unpredictable power production is responsible of variations in the voltage of the distribution lines that can be disruptive for the functioning of the supplied loads. Electric Spring (ES) is a device that faces such an issue by stabilizing the supply voltage of the critical load of a user in a simple but effective way. This paper is concerned with the stabilization characteristics of a user load supplied by a low-voltage distribution line and equipped with a reactive power-operated ES. After working out an ES model that facilitates the analysis of an ES-equipped user load, its stabilization characteristics are found for three types of line impedance, namely pure resistive, pure inductive and resistive-inductive. Comparison of the resultant characteristics shows the different performance of the ES-equipped user load under various types of line impedance.

The paper deals with the design of the compensation network in the wireless power transfer systems (WPTSs) devoted to charging the electric vehicles (EVs) while cruising. An inconvenience of these systems, commonly termed dynamic WPTSs, is the large variation of the power transferred to the EVs due to the correspondingly large change of the mutual coupling between the pickup and the track coils during the EV motion. Many attempts have been done to level such a power by help of multi-element compensation networks. In this paper, a simple one-element compensation topology, namely the series-series one, is considered and the design is aimed at evaluating its power leveling capabilities by a suitable sizing of the track-side compensation capacitor. As an alternative, the objective is pursued of maximizing the transferred energy. Formulation of the analytics for the two objectives is presented and the results obtained on a study case are given. It is shown that the achievement of the two objectives leads for a somewhat different size of the compensation capacitor, depending on the length of the pickup compared to that of the track coils.

The paper presents an overview about operation and control of the inverter-interface generation units (IGUs) when connected to a microgrid either alone or together with other generation units. The following key connection paradigms are considered: i) one IGU and a grid, ii) one IGU and one machine-interface generation unit, iii) a single IGU, and iv) two IGUs. After illustrating how the IGUs operate within the various paradigms, the methods used for their control are explicated in the case that there is no communications between the generation units: specifically, the methods of the power injection, the droop control, and the voltage generation. IGU-suited techniques that improve the droop control method, namely the so-called rotational power transformation and the virtual impedance, are explicated. At last, control of the generation units when the power requests are sent to them by a communication channel is addressed as well as the supervision tasks of a microgrid under a hierarchical control.

A novel topology is proposed for three-phase electric spring (TPES) to achieve specific functionalities. With respect to the existing one, the novel topology contains an additional three-phase transformer with the primaries located at the position of the non-critical three-phase load (NCL) of the existing topology and its secondaries connected to the new three-phase NCL, thus forming a new three-phase smart load (SL). To control the novel topology, the so-called modified δ control utilized for the single-phase electric springs is extended to the three-phase case. Thanks to these solutions, TPES exhibits a behavior entirely different from the existing ones. For instance, under a fluctuation of the line voltages, it exhibits a change of the voltages across NCL that has the same trend as the line voltages. Moreover, it regulates the voltages across the three-phase critical load even under both imbalanced and distorted grid conditions. The effectiveness of the novel TPES topology and of its control is validated by simulation results.

Track segmentation of the dynamic wireless charging (DWC) systems for electric vehicles is mandatory for magnetic field containment and energy loss avoidance. This paper is concerned with the reflexive segmentation of a lumped track, implemented by inserting a compensation network in the pick-up. After introducing performance figures for DWC systems with reflexive segmentation, namely segmentation ratio and power transfer efficiency, the inability of compensation networks with one capacitor in accomplishing the reflexive segmentation is explained. Then, the performance figures exhibited by two dual-capacitor compensation networks are analyzed. It is found that these networks reach a somewhat high segmentation ratio but at the price of a low power transfer efficiency just in the range of the load resistance where the segmentation ratio is higher.

Isolated multiport DC-DC converters offer an efficient solution to meet the increasing demand of integrating energy delivery elements (EDEs) of various type like renewable energy sources (RESs), energy storage devices (ESDs) and mains. This paper deals with an isolated three-port DC-DC converter (3PC): two ports are connected to EDEs, respectively to a RES and an ESD, and a port is connected to the load. The 3PC characteristics in terms of power capabilities and control laws are investigated for two discontinuous conduction mode (DCM) operations and two operational working situations. The DCM operations are i) full DCM (FDCM), with all the ports operating in DCM, and ii) mixed discontinuous conduction mode, with the ESD-connected port operating in DCM and the other ports in continuous conduction mode. The working situations are i) both EDEs deliver power to the load, and ii) RES delivers power to ESD and the load. The theoretical findings are explicated by waveforms and diagrams.

The main objective of this paper is to demonstrate the advantages of resonant power converters (RPC) in renewable energy sources. Due to their advantages over other topologies RPCs are more often used in many applications then after an overview of applications of RPC in different areas the paper focuses on the analysis, design, simulation and experimentation of an LsCsLpCpresonant circuit for renewable energy sources. To improve the dynamic performance of the converter supplying the resonant circuit, a hybrid control scheme, which combines both PWM and frequency control, is developed. Simulation and experimental results are achieved at full and half load conditions for a 3kW prototype. The parallel inductor Lp is taken as part of the magnetizing inductance, which therefore reduces the magnetic component count.

A control scheme is proposed for the three-phase electric springs (TPESs), based on the recently introduced δ control and an improved phase locked loop (PLL). The scheme utilizes three independent δ controls, one for each phase, to stabilize the voltages across the critical loads (CLs) while handing over imbalance and distortion of the microgrid voltages, in addition to their fluctuations, to the non-critical loads (NCLs). Instrumental in achieving this outcome is the operation of the improved PLL that separates the fundamental component of the positive sequence of the microgrid voltages from the other sequences and harmonics. The scheme is also able to stabilize the CL voltages under imbalance of CLs and NCLs. Simulation results obtained under various conditions of imbalance of the microgrid voltages and/ or the loads, and of distortion of the microgrid voltages, taken individually and together, show the effectiveness of the proposed control scheme of TPESs.

Inductive Power Transfer (IPT) is a promising solution for charging the electric vehicles (EVs). The first IPT systems (IPTSs) were needing a strong coupling between transmitter and receiver coils to achieve a satisfactory efficiency in the power transfer. Nowadays this drawback has been overcome by the resonant technology, which ensures an efficiency higher than 90% even with loosely coupled coils. Enforcement of this result requires that the transmitter and receiver stages of the IPTSs have the same resonance frequency, and that the supply frequency of the IPTSs coincides with the resonance one. In practice, any deviation in the values of the reactive parameters of the IPTSs produces a mismatch between supply and resonance frequency. This paper analyzes the impact of such a mismatch on both the efficiency and the power supply sizing factor of an IPTS with series-series resonant topology. The analysis embraces the mismatches ensuing from an update of the supply frequency to make resonating either the transmitter stage or the receiver stage or the IPTS input impedance. Throughout the paper, the IPTS developed to charge an electric city-car is taken as a study case.

The paper is concerned with the soft-switching capabilities of the Single Active Bridge (SAB) converter. At first, soft-switching of the double active bridge converter is reviewed. Then, operation of the SAB converter is investigated with the end of assessing its soft-switching capabilities in both the discontinuous and continuous conduction mode. It is found that the SAB converter experiences either full or incomplete soft-switching depending on the working conditions. Afterwards, the procedure to size the capacitors for implementing soft-switching is illustrated. At last, an under-development power supply equipment exploiting the theoretical findings of the paper is presented together with a preliminary design of its components.

In general, analysis of Resonant Power Converters (RPCs) is more complex than conventional converters. Consequently, it is common to adopt methods that facilitate the analysis. One of them is the First Harmonic Approximation (FHA). It assumes that only the fundamental harmonic of the current/voltage quantities affects the RPC operation, thanks to the filtering action of the resonant tank network (RTN) embedded in RPCs. The RPC stages can then be represented by simple equivalent circuits with sinusoidal solicitations and the operation can be studied by the standard linear ac analysis. In this paper the characteristics of RPCs with RTN made of two, three, and four elements are investigated using the FHA method. Input impedance, voltage gain and efficiency are derived and discussed for the various topologies. Merits and limitations of the topologies are also addressed.

The paper deals with the dynamic charging of the electric vehicles by an inductive power transfer (IPT) system with a segmented track. The reflexive properties of the IPT system is studied by evaluating the reactance of a transmitting coil when coupled with a pick-up with respect to uncoupled conditions. Different topologies for the pick-up circuit are evaluated, some of them introduced in this paper, with the aim of finding out the topology that offers the best reflexive properties. The impact of the different topologies on the IPT system efficiency performance is also argued.

Five-phase PM BLDC drives are a viable solution for safety-critical applications in road traction and aeronautics sectors. A common supply technique for these drives consists in the injection of square-wave currents into the motor phases, synchronized with the flat-top portion of the back-emf to produce both constant torque and maximum torque per ampere. In practice, the currents deviate from the ideal shape during the phase commutations, which further affects the torque characteristics of the drives. This paper analyzes the current behavior during the phase commutations for the five-phase PM BLDC drives as they exhibit some differences with respect to the three-phase counterpart. Then it uses the outcomes of the current analysis to derive the effective torque developed and the torque ripple exhibited by the drive as a function of the motor speed. The base speed of the drive is also determined. Throughout the paper, the differences from the well-known operation of the three-phase PM BLDC drives are pointed out.

The paper deals with the use of resonant converters for the power supply of electric equipment. After exploring the advantages of using the resonant conversion, an analysis of the three main resonant topologies, namely i) series-resonant, ii) parallel-resonant, and iii) a combination of them, is carried out and a series resonant converter is implemented. Considerations on the design of the resonant converter as well as on the selection of their components, including the HF transformer, are presented. Performance of the implemented series resonant converter is investigated in terms of dynamic behavior through experimental results.

The paper investigates the behavior of permanent magnet (PM) brushless DC (BLDC) drives in the stationary plane. The vectors of the phase currents and back-emfs are first drawn under ideal square-wave current supply. Development of a constant torque from the motor is explicated with the help of the vector representation. Trajectories of the tips of the motor current and voltage vectors are then traced for various motor speeds taking into account the phase commutations. Torque developed by the motor and its ripple are determined from the vector tip trajectories. Theoretical findings are supported by simulation results obtained by using the data of a PM BLDC drive designed for the propulsion of electric vehicles.

Stringent demands must be fulfilled when designing power supplies (PSs) for particle accelerators, such as stability, efficiency, accuracy, and electromagnetic compatibility. In this context, the paper analyzes the basic requirements to be considered when designing a PS for such applications. After reviewing the main circuitry topologies used in PSs, the electrical specifications and functional modes necessary to set up high-performance PSs are addressed. Problems concerning the fulfillment of the electrical specifications are discussed, followed by an overview of the common PS control methods. Finally, the impact of some of the discussed design considerations is evaluated for the PS of the magnets of particle accelerators.

PM brushless DC (BLDC) motors should be fed by square-wave currents synchronized with the back emfs to develop a constant torque with the required value. In practice, phase inductances and limited source voltage produce non ideal square-wave currents and unbalanced phase currents during commutations. Such phenomena affect the torque developed by the PM BLDC drives by deviating its value from the requested one and by giving rise to torque ripple. In this paper, an analytical study of the torque characteristics, namely motor torque and torque ripple, of PM BLDC drives is carried out as a function of the motor speed and is supported by experimental data. Torque characteristics are expressed in terms of a quantity distinctive of the motor, thus giving a generalized formulation to the results.

This paper presents two light electric vehicles (LEVs) with a electric propulsion system developed at an academic laboratory. One LEV is an electric city scooter powered by a lithium-ion battery pack and propelled by a wheel motor drive. The other LEV is an electric bicycle powered by a fuel cell system with the assistance of a supercapacitor bank. Power and energy design of the electric propulsion systems of the two LEVs as well as characterization of the energetic devices are illustrated.

This paper is concerned with the issue of protecting CAN networks against the consequences of babbling-idiot faults such as unscheduled traffic generated by a faulty node that denies any other communication. A full solution of the problem would greatly enhance the dependability of the CAN networks, making them applicable to safety-critical systems. After explaining the weakness of the native CAN protocol in tolerating the babbling-idiot faults, this paper shows how the FlexCAN architecture is suitable to tolerate them effectively. To this aim, a simple bus guardian is proposed and tested. The results of the test are given in this paper.

The paper gives an overview of the communication architectures adopted in the industrial automation for the electrical drives, ensuring a fast data exchange and high performance control. An attempt is made at defining real-time operation for this application field, at reviewing the standardization work done to unify the electrical drive interfaces, and at encompassing the recently accepted solutions, including those based on the industrial Ethernet.