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This paper analyzes two different design procedures for a series-parallel compensated WPT battery charger, based on different definitions of the operating resonant frequency in the condition of maximum link efficiency. The behaviour of the voltage gain magnitude and the input impedance angle of the resulting WPT links is studied for different loads and coupling coefficients. The design algorithms are supported by analytical formulas derived from an exact circuit analysis of the WPT link, avoiding approximations as far as possible. To support the theoretical approach a case study is proposed, in which both design procedures are implemented considering specifications in line with the actual automotive standards. To conclude, a characterization of the efficiency in both cases is derived.

Receiver position sensing is investigated in a dynamic wireless power transfer (DWPT) system for electric vehicle (EV) charging. Exploiting the peculiar behaviour of the resonator arrays input impedance, it is possible to identify the position of the receiver coil by exciting the first array resonator with a signal at a proper frequency and measuring the resulting current. An analytical expression of the input impedance of the resonator array coupled with the EV receiver coil placed in a generic position is provided; its sensitivity to different circuit parameters is also analysed. The outline of a simple and effective algorithm for the localization of the EV is proposed and applied to a test case.

The possibility of increasing the transmission efficiency in mid-range wireless power transfer (WPT) applications can be achieved by inserting resonant relay coils between the transmitting and receiving sides of the device, forming an array of magnetically coupled resonant circuits, over which a receiver can be placed. This is a very cheap solution for improving the performance of the WPT apparatus, even if the complexity of the system increases, requiring a complete and detailed investigation for a smart design and control of the apparatus. The presented study investigates the current distribution in the coils of the array, which revealed strong peaks in magnitude depending on the load and receiver position. The analysis is carried out with the transmission line (TL) theory and it is performed for different positions of the receiver, as well as for different load conditions. Furthermore, a real application is considered and discussed, which includes the presence of a power converter as power supply and a battery charging system as load. Each resonant circuit resonates at 150 kHz and the whole apparatus is capable to transmit power up to 1 kW with an efficiency around 70%. The theoretical results have been validated with experimental measurements.

Power converters for wireless power transfer (WPT) and, in general, for electrical vehicle charging are evolving in terms of nominal power and performance, bringing along non negligible emissions in the supraharmonic range (2 kHz to 150 kHz). The large installed power and the high concentration with a relatively short separation distance can be addressed by feeding the converters through a DC grid for better dynamic response and lower impedance. The prediction of conducted emissions in real supply conditions requires carrying out measurements with low impedance values, lower than those available in line impedance stabilization networks (LISNs) for AC grids. This work proposes an approach to extrapolate converter emissions in an ideal 0 Ω condition, that together with the input impedance curve (determined by a least mean square approach) form a Norton equivalent circuit of the converter. The interaction of the converters with the DC grid and superposition of emissions can be then thoroughly evaluated by means of a general ladder grid scheme to which the Norton equivalents are connected. Such a grid model is suitable for Monte Carlo simulation aimed at assessing the degree of compensation between sources of emissions and the overall network distortion. Results using a Simulink model are provided considering emissions aggregation and compensation under random phase conditions for the following cases: close-by and separated sources (5 m and 100 m cable separation, respectively); increased number of sources studying scenarios with 3 and 10 sources; and using different resolution bandwidth values (200 Hz and 500 Hz) against a random change of the frequency of the emission components.

In modern inductive power transfer (IPT) systems, especially if devoted to electric vehicle (EV) charging, the alignment between the transmitter and receiver coils still represents one of the most relevant issues. Besides a well-known drop in the efficiency and transferred power, operating in a misalignment condition also affects the conducted emissions towards the grid, that increase as the coupling between the transmitter and receiver weakens. This paper investigates the conducted emissions of an IPT system for different alignment conditions. The system is supplied by a full-bridge inverter and feeds an equivalent load of 5 Ω through a full-bridge diode rectifier. The inductive coupling is realized with two identical square coils, that resonate with lumped capacitors connected in series at the resonant frequency of 147 kHz. A simple model has been used for the prediction of the differential-mode conducted emissions and the results have been compared with experiments. The measurements have been performed with the general setup for conducted emissions described in IEC standards and the disturbance voltages have been processed to assess the highest emission level which defines the worst case scenario for electromagnetic compatibility.

This paper presents a study of the magnetic near field produced by an inductive power transfer (IPT) system composed of an array of magnetically coupled resonators that may be embedded in a table for powering desktop electronic devices. The analysis is performed considering different positions of the receiver circuit, namely different structures of the system, that lead to very different behaviour in terms of the generated magnetic field. Significant peaks of the magnetic field have been detected in correspondence of certain resonators of the array for different positions of the receiver, thereby making shield actions necessary. An estimation of the shielding effectiveness of a shield used to reduce human exposure to the generated magnetic field is carried out. The theoretical results have been validated with experimental measurements.

A numerical methodology is proposed for the calculation of transient electromagnetic interference induced by overhead high-voltage power lines in metallic structures buried in soil—pipelines for oil or gas transportation. A series of 2D finite element simulations was employed to sample the harmonic response of a given geometry section. The numerical inverse Laplace transform of the results allowed obtaining the time domain evolution of the induced voltages and currents in the buried conductors, for any given condition of the power line.

Phaeodactylum tricornutum is considered a promising source of polyunsaturated fatty acids (PUFAs), in particular eicosapentaenoic acid (EPA). In this study, P. tricornutum cultivation using waste products from anaerobic digestion (i.e. liquid digestate and CO2) was tested and scaled-up in closed and open prototype systems. The chemical composition of algal biomass was evaluated to optimize the lipid content. Algal productivity and composition, especially in terms of PUFAs, were not modified by the use of waste CO2. Digestate led to a lower protein (24%) content than medium (36–37%), without affecting lipid amount (about 37%). Algal and EPA productivity were nearly two-fold higher by using photobioreactors (0.075 g biomass L−1 day−1 and 1.62 mg EPA g−1 day−1) than open ponds, which are more influenced by environmental conditions. This study highlights that economic and environmental benefits could be achieved by using waste CO2 and liquid digestate from anaerobic digestion for microalgae cultivation.