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As a consequence of the growing demand for mobility and the requirements for reduced environmental pollution, railway traction systems are receiving increasing interest. Researches are analyzing new technologies and managing solutions to increase energy efficiency in the railway infrastructures. Many studies proposed the oppor-tunity to introduce the technology of energy storage systems (e.g., Wayside Energy Storage Systems - WESS) in traction infrastructures. WESS can be able to: i) reduce voltage drops; ii) save braking energy; iii) support Traction Power Substations in supplying traction power peaks. A relevant topic in using WESSs in railway infrastructure is to verify their impact in case of faults. Studies on short circuit analyses are required to verify the correct rating of the protection devices and the opportunity to use new protection devices and mode of operating, when the new technology is integrated. In this paper, the typical Italian DC railway power system is investigated. Specifically, the contribution of WESS to the short circuit currents is assessed by examining transient and steady-state conditions.

The scientific literature is paying particular attention to Ultra-Fast Charging Stations (UFCSs) that can make charging times of Electric Vehicles (EVs) comparable with the refuelling time of internal combustion engine vehicles. In this context, scheduling charging algorithms to manage the available resources deserve significant attention. This paper proposes an online scheduling algorithm for UFCSs equipped with Battery Energy Storage Systems. The charging profile is obtained by considering the power and energetic constraints related to both infrastructure and EVs. The constraints are assessed according to the efficiency of the infrastructure, for which a power losses estimation approach was proposed and then detailed for the UFCS realized at our department. Even, the dependence of the maximum EV charging rate on the State of Charge (SoC) is considered. These aspects are usually neglected. Thus, starting from the measurements of the maximum charging rate for two commercial EVs, numerical simulations were performed using the proposed algorithm according to two different scheduling policies, i.e., the not-preemptive ‘First Come Best Served’ and the preemptive ‘Round Robin SoC’. The numerical results highlight the difference between the two policies regarding the allocation of resources among vehicles and how the SoC of the BESS affects the overall charging profiles.

Light rail vehicles with onboard energy storage systems have gained increasing interest due to higher efficiency and lower or null local emissions in catenary-less operation. Their traction circuit conventionally employs inverters to drive the traction motors and DC/DC converters to manage the onboard sources. Recently, the concept of multi-source inverter (MSI) was introduced for single-stage integration of AC loads and multiple DC sources without. This paper evaluates the feasibility and attractiveness of the MSI for single-stage integration of batteries and supercapacitors to the traction motors in a catenary-less tramway vehicle. The configuration of the MSI-based hybrid energy storage system is detailed. Numerical simulations are carried out to assess its performance over a typical driving cycle. Furthermore, the proposed architecture is compared to a standard configuration employing a DC/DC converter to control the supercapacitors, with focus on power losses and volumes of the converters and DC sources.

The number of Plug-in Electric Vehicles (PEVs) available on the car market is continuously growing. The electrification of the mobility is definitely related to the diffusion of the charging infrastructures widely distributed on the territory. Indeed, PEV owners request for charging stations able to offer features adequate to the expectations. They are expected to be able to recharge vehicle's on-board battery in a ten of minutes. In this paper, Ultra Fast Charging Stations (UFCSs) are investigated. The stations are discussed in terms of electric schemes and modalities of control. There is a focus on components, systems, state variable and security level. Moreover, the UFCS realized at the University of Naples Federico II is highlighted. The lab prototype is discussed in terms of configuration and rated values. The results of some numerical tests are carried out. They point out both the main features of the charging slots and the requirements of load emulators for UFCS.

The paper deals with the power control of a delta connected Cascaded H-Bridge (CHB) converter equipped with photovoltaic (PV) modules. A hierarchical architecture of energy management is proposed: A 'Module level' controller performs a Maximum Power Point Tracking (MPPT) algorithm to achieve the optimal utilization of each PV module; a 'Leg level' controller manages the power flow control within the modules of a single CHB phase leg, and a 'System' level controller manages the active power flow between the three CHB phases and the reactive power generation towards the grid. The active power control is aimed at the compensation of the mismatches between the different PV-powered modules, which may come from partial shadowing phenomena. A power unbalance compensation between cascaded modules is implemented through the Pulse Width Modulation (PWM) algorithm, while the unbalance compensation between the phases is implemented through the phase currents control. To compensate the active power unbalance due to PV module mismatches, the obtained effect is equivalent to the injection of a zero sequence current. A reactive power control has been implemented to perform a power factor (PF) correction, too. A set of numerical simulations validate the effectiveness of the algorithm, which can simultaneously achieve the desired active power generation from all the PV panels and the desired PF control towards the grid.

The paper deals with mathematical modelling and the control system for UltraFast Charging Stations (UFCS) based on DC micro-grid concept and Energy Storage System Integration to feed new Electrical Vehicles (EVs) at 800V DC in order to reach the EVs power requirement for charge-time less than 10 min. The UFCS integrates a battery energy storage system (BESS) to reduce the peak power of AC main grid, decoupling the dynamics of the DC charging station from the AC grid by means of its dedicated control system. Designing procedure and Control Strategy, based on Load Levelling power management, are dealt with numerical simulation results in Matlab-Simulink software, presented in order to verify UFCS performance and the charging station’s dynamics.

Wayside Energy Storage Systems (WESSs) are studied for energy saving of railway system. To maximize the energy saving effect of WESSs, a power control strategy which realize higher charge/discharge power is necessary. Currently, Current Based Control, which regulates current of ESDs, and Voltage Based Control, which regulates DC input voltage are generally applied. However, the difference of the dynamic characteristics between Voltage Based Control and Current Based Control has not discussed before. The aim of this paper is to compare the dynamic characteristics of Voltage Based Control and Current Based Control. First of all, a theoretical analysis on dynamic characteristics of both control strategies is carried out. This analysis revealed the maximum limitation of a control gain, which has an impact on the energy saving, for each control strategy. Utilizing these maximum control gain, an analysis on the static characteristics is performed to verify the energy saving effect for each control strategy. As a result, an advantage of Voltage Based Control is verified from the viewpoint of contribution to energy saving in DC-electrified railway system.

Storage technologies devices are very interesting solutions for improving energy saving and guaranteeing contemporaneously to enhance the electrical characteristics of Light Rail Transit (LRT) systems. Onboard Energy Storage System based on Lithium Ion Capacitor (LiC) devices represent a viable engineering solution for energy saving optimization. The authors suggest a multi-objective design optimization procedure based on catenary and storage power losses minimization. A test characterization of ESS has been presented in order to use the better appropriate modeling of LiC for the examined case study. The numerical simulation allows to confirm the feasibility of the proposed design procedure.

Worldwide expectancy of larger fleets of PEVs requires an increasing number of available fast and ultra-fast charging stations. In order to reduce the impact on the distribution grid of the power demand of large fleets of PEVs, the coordination of charging in stations equipped with multiple charging slots is mandatory. The paper suggests a smart charging profile of electrical vehicles based on an optimization problem in order to minimize the charging time. Constraints in term of limits on the power supplied by DSO, the available state of charge (SOC) of the BESS and the energy requested by the PEVs are taken into account. Some simulations are presented to validate the suggested charging strategy.

In this paper an enhanced distributed maximum power point tracking (DMPPT) algorithm, along with an improved hybrid modulation method for a photovoltaic (PV) module-level Cascaded H­Bridge (CHB) inverter, is proposed. The advantages and drawbacks of the CHB topology in distributed PV generation systems are highlighted. The main benefits are related to the higher granularity of the PV power control, which mitigates mismatch effects, thus increasing the power harvesting. Nevertheless, heavy unbalanced configurations need to be properly addressed by means of dedicated control action. The proposed control strategy allows to overcome the operating limits of PV CHB inverter, by integrating in the MPPT algorithm a limitation of the individual cell modulation index. Experimental tests carried out on a laboratory prototype of a single­phase seven­level PV CHB inverter, evidence the effectiveness of the proposed control and modulation approach in terms of extended operating range and MPPT efficiency.

This work reports a study on a tidal current system named GEMSTAR, composed of two hydrokinetic turbines supported by a floating submerged structure. A flexible mooring cable links the floating support to the seabed allowing the free rotation of the system and its alignment to changing current direction. The work is mainly focused on the design of the turbine blade with two objectives: keeping a constant power output above the rated power condition and limiting the thrust increase between rated and maximum operating speed. A fixed pitch blade was considered, in order to reduce the costs associated to a complex pitch control mechanism. An analytical procedure for blade design is proposed and validated by comparison to other numerical methods. Above the rated current speed, the power is held constant while the rotational speed of the turbine and of the generator increases, assuming an over-speeding control strategy. The adopted design configuration relies on the possibility of the generator to operate in de-fluxing working conditions. As reported in the last part of this study, a numerical model of the generator has also been developed and applied to a test case in order to analyse the electric behaviour of the system.

The paper suggests a battery wireless charging control for e-bike sharing service implemented at University ‘Federico II’ of Naples. The wireless battery charging system is based on Series-Series Resonant Converter (SS-RIPT) tracking of battery Constant Voltage (CV)/Constant Current (CC) mode. State of charge identification has been implemented using primary transformer current measurement. A Fourier frequency domain methodology has been implemented in order to identify the secondary coil current of resonant transformer and the battery voltage. Numerical results have been carried out in order to validate the identification procedure.

This paper presents a design optimization for an electrical kart that will be used in sport racing competitions. This work is carried out within the project "E-Kart", sponsored by University of Naples Federico II, that consists in developing integrated high-tech devices for the design and implementation of electrical drive using high density of Lithium Ion Batteries Technology. The aim of paper is the preliminary sizing of the main components of electrical drives for satisfying the performance requirements in terms of minimizing time lap, considering constraints like maximum speed for lap, maximum weight of battery systems and dynamic force of racetrack (e.g. curve and straight). The paper shows the optimal design procedure on basis of fixed racetrack identifying the speed profile, output mechanical power to the wheel and kWh of Energy Storage Device.

The present work reports a study on a tidal current system named GEMSTAR, composed by two hydrokinetic turbines supported by a floating submerged structure. A flexible mooring cable links the floating support to the seabed allowing the free rotation of the system and its alignment to changing current direction. The work is mainly focused on the design of the turbine blade with two objectives: keeping a constant power output above the rated power condition and limiting the thrust increase between rated and maximum operating speed. A fixed pitch blade was considered, in order to reduce the costs associated to a complex pitch control mechanism. An analytical procedure for blade design is proposed and validated by comparison to other numerical methods. Above the rated current speed, the power is held constant while the rotational speed of the turbine and of the generator increases, assuming an over-speeding control strategy. The adopted design configuration relies on the possibility of the generator to operate in defluxing working conditions. As reported in the last part of the paper, a numerical model of the generator has also been developed and applied to a test case in order to analyse the electric behaviour of the system.

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.

As one of the solution for energy saving in DC-electrified railway system, wayside energy storage systems (WESSs) are recently studied. In the previous study, current based control, which regulates current of ESSs, and voltage based control, which regulates the filter capacitor (FC) voltage, have been proposed as a power control method for WESSs. However, the difference between these two power control methods has not discussed before. In this paper, a theoretical comparison between voltage based power control method and current based power control method is carried out focusing on each static characteristic. Furthermore, an influence of distance between a WESS and a rail vehicle on characteristics of each control is also considered. Though the study in this paper, theoretical comparison between both control methods is carried out. Results of this paper contribute to establish a method to design WESSs which realize maximum energy saving effect with minimum energy capacity of energy storage devices.

This paper is aimed to present an experimental criterion that allows researchers and designers to evaluate the performance of DC micro-grids dedicated to charging operations of full EV. The laboratory methodology is explained through tests on a demonstrator of power architecture, specifically designed as simplified case study of a DC charging station for fully-electrified low-power two-wheeler, such as: electric scooters and bikes. This experimental prototype is composed by a 20 kW AC/DC bidirectional grid-tied converter, which realizes the DC conversion stage, and two DC/DC power converters, interconnected with the micro-grid through a DC bus. The power architecture provides on one hand the charging operations of electric two-wheeler battery packs and on the other hand the integration of the micro-grid with an ES buffer, which has the main function of supporting the main grid while an electric vehicle is on charge. The performance of the considered architecture is characterized and analyzed in different operative conditions, through a specific management of the energy fluxes. The laboratory tests evaluate efficiency, charging times and impact on the main grid, with specific reference to the DC charging operations of electric scooters. The obtained experimental results show the advantages of adopting the DC buffer architecture, compared with an AC commercial battery charger, considered as reference in this work. Finally, the numerical data of this paper, related to the single power components and to the experimental results evaluated for the whole demonstrator, effectively support the lack of knowledge in the literature about charging stations for EVs. In fact, these pieces of information, based on experimental tests, are expected to support the building of simulation models and the identification of the best energy management and control strategies to be adopted in a smart-grid scenario, characterized by distributed generation systems including renewable energy sources.

In this paper, an advanced control strategy for grid­tied photovoltaic (PV) cascaded H­bridge (CHB) inverter is proposed. The circuit topology consists of a proper number of power cells (H­bridge configuration) connected in series and supplied by individual PV modules. The adopted control method is a mixed staircase­PWM technique performed by means of a sorting algorithm to determine cells' switching state. The cells' state is related to the need of charging or discharging a particular cell much more than the others by calculating the voltage error at each dc­link (e.g., by considering the difference between the maximum power point tracking (MPPT) reference and the measured quantity). A dedicated PO thus, increasing the power extraction even in mismatched conditions. In order to prove the effectiveness and feasibility of the proposed approach, a set of experiments are performed on a laboratory prototype of a single­phase five­level PV CHB. The control section is implemented on FPGA by using a dSPACE real­time hardware platform; thus, obtaining fully dedicated digital circuits. Experimental results show good performance in terms of MPPT efficiency, total harmonic distortion, and power factor in both normal operation and mismatch conditions.

This paper presents a control strategy for the power flow management of a wayside energy storage system based on a supercapacitor technology installed in a tramway network. The control is based on the management in real time of voltage levels at catenary point connections in order to optimize the energy flow among the running tramcars and substations with the goals of improving the energy saving and reducing the voltage drops in the supply network. The suggested control algorithm was experimentally validated using a laboratory-scale model to verify the effectiveness of the strategy. A lithium-ion capacitor module with 72 series-connected laminated cells of the JSR Micro ULTIMO type was used. Thus, an emulation of a real tramway network in the city of Naples (ANM) was implemented to evaluate the potential impact in terms of costs/benefits of the next installation on the ANM network.

In this paper a suitable digital controller of a RIFT system for e-bike clever mobility is proposed and experimentally validated. Specifically, it is provided a detailed mathematical continuous-time nonlinear model of the system composed of a transformer, a bridge with characteristics of the ideal and real diodes, a filter and a battery, valid for any behavior of the supply voltage. Then, it is provided a suitable discrete-time model of the continuous model to design a digital controller. Finally, it is proposed and experimentally validated a robust discrete-time controller, which allows to charge the battery with a fixed behavior of the current.

Objective:This paper analyses the Modular Multilevel Converter (MMC) topology, where each individual Sub Module (SM), in half bridge configuration, is directly fed by an elementary electrochemical cell.Methods:The aim is to investigate how the reference voltages influence the cells currents waveforms, determining how the active powers and the losses are distributed among the cells. Considering a 2-level Voltage Source Inverter (VSI) topology working in the same conditions, the ratio between the MMC total cells losses and VSI total cells losses is calculated. After showing the system architecture and mathematical model, the cells current waveform investigation is presented and detailed both for triangular and sinusoidal voltage reference waveform.Results:Finally, the results are critically discussed with particular focus on the comparison between the MMC and the VSI topologies.

This paper focuses on three alternative railway systems (i.e., railway, urban metro and city tram). An approach to assess the size of an on-board energy storage unit is proposed. The unit is designed to supply the three trains along a catenary-free track. The equations of motion are formulated in a common case. The approach solves the system of equations by means of an optimization procedure where a set of constraints on the representative variables is assigned. Service duty cycle and energy requirements are characteristics of the three alternative systems. The results of the numerical simulations focus on the design of a battery-based storage unit to be equipped in the rolling stock vehicles. Specifically, the performance required to the storage units in the three alternative configurations are investigated and compared. Some final notes pointed out the impact of the design constraints on the unit sizing.

In this paper, a photovoltaic (PV) module-level Cascaded H­Bridge (CHB) inverter with an integrated Battery Energy Storage System (BESS) is proposed. The advantages and drawbacks of the CHB circuit architecture in distributed PV generation systems are highlighted. The main benefits are related to the higher granularity of the PV power control, which mitigates mismatch effects, thus increasing the power harvesting. Nevertheless, heavy unbalanced configurations due to the intermittent nature of PV sources need to be properly addressed. In order to smooth the PV fluctuations, a Battery Energy Storage System is used to provide both an energy buffer and coordination of power supply and demand to obtain a flat profile of the output power. In particular, by exploiting the inherent modularity of the conversion circuit, a distributed storage system is also implemented by splitting the battery into smaller units each of which represents the backup module of a single power cell of the PV CHB. The proposed design and control strategy allows overcoming the operating limits of PV CHB inverter. Simulation results, carried out on a single­phase nineteen­level PV CHB inverter, evidence the effectiveness of the proposed design and control approach to minimize the adverse impact of deep mismatch conditions, thus enabling continuous power output by compensating PV power fluctuations.

In this paper the control of a grid-tied PV (Photovoltaic) Cascaded H-bridge inverter is discussed. The operation principle of the considered circuit is analyzed and a particular attention is paid to the different modulation techniques well-suited for this configuration. Moreover, some critical implementation issues are addressed, while a fair comparison between the proposed modulation scheme and the Phase Shifted PWM (Pulse Width Modulation) is carried out. The adopted control strategy is based upon a sorting algorithm in order to modulate only one power cell (i.e. H-bridge) per sorting cycle while the others are in fixed state. This technique allows to reduce power switching losses, thus increasing overall system efficiency. The numerical results reported in the paper permit to confirm the feasibility of the proposed modulation strategy and the better performance with respect to PS-PWM in terms of power efficiency.

The paper presents the state of the art and the future trend of the Energy Management. The “Energy Management” term is often used to indicate one or more techniques adopted in the new more electric aircraft, to avoid the generator overload. The designer can use four different approaches, or a combination of them to reduce the over sizing of the generators. The first method regulate the energy exchanged between sources in order to share the power between them. The second method uses storage elements (battery or supercap) to limit the peak power. This elements are connected to the power bus through DC/DC converters that are in charge of the power flux regulation and work like active filters. The third method regulate the loads, or switch them ON/OFF limiting the generator overload. The last method works with the fast reconfigurable network and distribute loads between sources in order to charge each generator within its capability. Some example of experimental works are also provided in the work.

This paper is focused on the evaluation of theoretical and experimental aspects related to the different operation modes of a laboratory power architecture, which realizes a micro grid for the charging of road electric and plug-in hybrid vehicles. The analyzed power configuration is based on a {DC} bus architecture, which presents the main advantage of an easy integration of renewable energy sources and buffered storage systems. A first phase of simulations is aimed to evaluate the main energy fluxes within the studied architecture and to identify the energy management strategies, which optimize simultaneously the power requirements from the main grid and charging times of different electric vehicles. A second phase is based on the experimental characterization of the analyzed power architecture, implementing the control strategies evaluated in the simulation environment, through a laboratory acquisition and control system. Then the experimental results coming from the laboratory prototype are compared with the simulation results, in order to achieve a better parameter setting of the simulation model for the analyzed structure. This preliminary analysis makes possible other simulations to be carried out on more complex architecture of micro-grids, taking into account the integration of renewable energy sources and high power buffer storage systems. Particular attention is also given to the analysis of ultra-fast charging operations and the related performance in terms of total efficiency, charging times, total power factor and power requirements from the main grid. This study represents a further step toward the new concept of smart grid scenario for electric vehicles.

The paper suggests an energy management control strategy of wayside Li-ion capacitor (LiC) based energy storage for light railway vehicles (LRV). The installation of wayside supercapacitor (SC) storage devices, as widely recognized, allows the recovery of the braking energy for increasing the system efficiency as well as a better pantograph voltage profile. A new type of SC, LiC, interfaced with dc-interleaved converter has been presented. This technology has an energy density comparable to batteries and power density much higher than the batteries. The authors propose a control strategy based on the maximum kinetic energy recovery throughout braking operations of the running vehicles. The stored energy comes back to the vehicles during the accelerations. The strategy stays on the knowledge of the state of charge of LiC device and the actual vehicle speeds. In particular, the control algorithm evaluates, in real time, the actual value of LiC voltage and current references on the basis of the vehicles inertial forces and acceleration estimations, taking into account the power losses of the system. Experimental tests made on electromechanical simulator, equipped with a 136-V, 30.5-F LiC module, fully confirm the validity of the suggested control. Finally, experimental characterization of LiC module has been achieved.

Microgrids can offer various benefits to electricity consumers, but these benefits must be compared with the corresponding investment cost for ensuring financial feasibility. This paper is focused on the problem of optimally sizing, from an economic perspective, the Distributed Energy Resources included in a DC Microgrid, determining the optimal mix of Distributed Generators and Energy Storage Systems, taking also into account the opportunities of Load Management. The proposed procedure is based on Mixed Integer Linear Programming and allows to determine the optimal sizes of Distributed Energy Resources which minimize the Microgrid Total Cost of Ownership, given location and load characteristics. The procedure is formulated as a quite general method that can be used for different microgrid architectures and different generation and storage technologies, although in this paper it is applied to a grid-connected DC microgrid with PV generation and storage system. Results of numerical applications to a case study demonstrate the effectiveness of the proposed sizing procedure.

In this paper, a detailed model of a RIPT system, to design and control a power charging station for e-bike clever mobility, is proposed. Specifically, it is provided a detailed mathematical nonlinear model of the system composed of an oscillator transformer and a bridge with characteristics of the ideal and real diodes, valid for any behavior of the supply voltage. This model is used to both theoretically and via simulation analyze the RIPT system powered with square wave voltage for different values of the duty-cycle, frequency and of the parameters of the battery. Moreover, it is proposed a discrete–time detailed model and the related simulator to design and realize a simple and robust discrete–time control system, which allows to charge the battery with a fixed behavior of the current. The proposed model has been validated with significant experimental tests.

Storage systems are recognized as a viable mean for improving the performances of electrified transportation systems. The recent literature highlighted some significant solutions to design problems thanks to procedures-based upon optimization theory. More specifically, an analytical solution can be deduced based on the formulation of an isoperimetric problem. This formulation exhibits the intrinsic ability to determine the optimal storage size, once the train power absorption has been fixed. Unfortunately, the analytical expression is not very advantageous to the control because it includes terms that require both real-time traction load estimation and its prediction over the whole traction cycle. The originality of this paper lies in the suitable simplification of the control structure, avoiding both traction load estimation and the heavy computations linked to predictive analysis. The storage device control law is reduced to an appropriate constant voltage over the whole traction cycle. The traction load prediction is performed offline, and the robustness of the consequent control law is tested against random variations in significant traction parameters. Some comparisons are made using other control strategies proposed in the technical literature. Finally, numerical and experimental results confirm the validity of the affected assumptions.

The installation of stationary ultracapacitor storage devices, as widely recognized, allows the recovery of the braking energy for increasing the energy efficiency as well as a better pantograph voltage profile. In the paper a new methodological mean is proposed for determining the fundamental characteristics of this kind of storage device, characterized by high power density, interfaced with the railroad by a bidirectional dc–dc converter. More specifically, the parameters of the storage system can be determined by employing an optimization technique which in a quite general way is able to take contemporaneously into account several aspects in an integrated manner. Some considerations are performed for properly taking into account the stochastic aspects of the design procedure. Numerical simulations with respect to a case study are presented, pointing out the potentiality of the tailored technique. Experimental results are also reported, with reference to an electromechanical simulator, in order to put in evidence the effectiveness and the actual implementation of the proposed optimization technique.

This paper presents the design and the experimental tests of an E-bike 300-W battery charger for a cyclo-station based on wireless power technology. In particular, a series resonant inductive power converter with an E-geometry magnetic core topology is proposed. A mathematical model is developed and a performance analysis is conducted to determine the voltage transfer function, maximum power transfer capability, efficiency for different air-gaps (1–3 cm), and misalignments (0.5–1.5 cm). Also, it is performed analytical and experimental investigations of the minimum and maximum relative frequency points of active input power and efficiency in order to determine how these points changed as the resistance load varied. The results of the analyses indicated that the maximum frequency points of active input power are different from the maximum frequency points of efficiency and the zero-frequency points of reactive input power. This means that maximum power transfer and efficiency conversion are not obtained in correspondence with the resonant frequency. For this purpose, it is conducted a wide frequency characterization of 30–50 kHz around the designed resonant frequency of 40 kHz. An iterative electrical and magnetic design procedure is proposed based on 3D finite element analysis. Simulation and experimental results are presented for a full-sized prototype. The design of the E-bike battery charger is validated in terms of rated input voltage and output power for different air-gap configurations.