Influence of Non-Linearity in Losses Estimation of Magnetic Components for DC-DC Converters

In this paper, the problem of estimating the core losses for inductive components is addressed. A novel methodology is applied to estimate the core losses of an inductor in a DC-DC converter in the time-domain. The methodology addresses both the non-linearity and dynamic behavior of the core magnetic material and the non-uniformity of the field distribution for the device geometry. The methodology is natively implemented using the LTSpice simulation environment and can be used to include an accurate behavioral model of the magnetic devices in a more complex lumped circuit. The methodology is compared against classic estimation techniques such as Steinmetz Equation and the improved Generalized Steinmetz Equation. The validation is performed on a practical DC-DC Buck converter, which was utilized to experimentally verify the results derived by a model suitable to estimate the inductor losses. Both simulation and experimental test confirm the accuracy of the proposed methodology. Thus, the proposed technique can be flexibly used both for direct core loss estimation and the realization of a subsystem able to simulate the realistic behavior of an inductor within a more complex lumped circuit

Rifting Kinematics Produced by Magmatic and Tectonic Stresses in the North Volcanic Zone of Iceland

In the North Volcanic Zone of Iceland, we studied with the greatest possible detail the complete structural architecture and kinematics of the whole Theistareykir Fissure Swarm (ThFS), an N-S-trending, 70 km long active rift. We made about 7500 measurements along 6124 post-Late Glacial Maximum (LGM) extension fractures and faults, and 685 pre-LGM structures. We have collected the data over the last 6 years, through extensive field surveys and with the aid of drone mapping with centimetric resolution. In the southern sector of the study area, extension fractures and faults strike mainly N10°-20°, the opening direction is about N110°, and the dilation amount is in the range 0.1–10 m. In the central sector, faults and extension fractures strike mainly N00-10°, the opening direction is N90-100°, and the dilation amount is 0.1–9 m. In the northern sector, extension fractures and faults strike N30-40°, the opening direction is about N125°, and the dilation amount is 0.1–8 m. The variations in strike are attributable to two processes: the interaction with the WNW-ESE-striking Husavik-Flatey transform fault and Grímsey Oblique Rift (Grímsey lineament), and the structural inheritance of older NNE- to NE-striking normal faults. Most extension fractures show a minor strike-slip component: a systematic right-lateral component can be accounted for by the interaction with the WNW-ESE-striking fault zones and the regional, oblique opening of the rift. We regard dyke propagation as a possible cause for the more complex strike-slip components measured at several other fractures. Cumulated dilation and fracture frequency decrease along the rift with distance away from the Theistareykir volcano, situated in the central sector of the ThFS. This is interpreted as a decrease in the number of dykes that are capable of reaching great distances after being injected from the magma chamber

A Secondary-Side Controlled Electric Vehicle Wireless Charger

In this paper, the design procedure of an electric vehicle (EV) wireless charger is presented. Unlike most of the systems available in the literature, the proposed charging system is regulated from the vehicle side. The on-board electrical circuit automatically adapts the resonant compensation to guarantee compatibility with the primary inverter characteristics and achieve high transmission efficiency without communication between sides. Moreover, the proposed control strategy, used to regulate the secondary full active rectifier (FAR), allows the supply of the the EV battery, maximizing the efficiency during the whole charging process

Short-term reproducibility of nocturnal non-dipping pattern in recently diagnosed essential hypertensives.

Objective: To investigate in a selected population of patients with a recently diagnosed essential hypertension the short-term intrasubject variability of diurnal changes in blood pressure (BP). Methods: Two hundred and eight consecutive, recently diagnosed, never treated essential hypertensives (119 men, 89 women, 46 ± 12 years) underwent 24-h ambulatory BP monitoring (ABPM) twice within 3 weeks. Dipping pattern was defined as a reduction in average systolic and diastolic BP at night greater than 10% compared to average daytime values. Results: 177 subjects (85%) showed no change in their diurnal variations in BP. Of the 159 subjects who had a dipping pattern on first ABPM, 134 (90.6%) confirmed this type of profile on the second ABPM, while 15 (9.4%) showed a non-dipping pattern. Of the 59 subjects who had a non-dipping pattern on the first ABPM, 43 (72.2%) confirmed their initial profile on the second ABPM, while 16 (28.8%) did not. Conclusion: These findings indicate that short-term reproducibility of diurnal changes in BP in early phases of untreated essential hypertension, characterized by a large prevalence of dipping pattern, is overall satisfactory. However, our study underlines that also in this particularly selected population of hypertensives the definition of non-dipping status on the basis of a single ABPM remains unreliable in about one-third of patients