In this paper, a behavioral static model of GaN HEMT is proposed. Different mathematical formulas have been tested to find the best for emulating the static behaviour of a 650V GaN HEMT prototype manufactured by STMicroelectronics. In literature, almost all the proposed formulas did not satisfy the target characteristics. The study of the new mathematical formulas, proposed in this paper, starts from the analysis of the models present in the literature that are rewritten and adapted for this model. Furthermore, these new equations are temperature dependent. The simulated curves of the static characteristics have been compared with those extracted by means of laboratory measurements. The model has been developed exploiting some features of STMicroelectronics models of SiC power MOSFETs.

This paper accurately estimates the dependency of the efficiency of multi-output Flyback converters from different designing parameters. This task has been accomplished by proposing a dedicated simulation circuitry that accurately models the MOSFET and the passive components. Through a dedicated parametric script, an automatic set of simulations has been performed aiming at providing a powerful tool to identify the optimum value of each designing parameter to maximize efficiency. A prototype of a double-output Flyback converter has been used to prove the effectiveness of the proposed model by comparing the bench measurements with the simulation results.

The super-junction MOSFETs enhanced with an additional source, called Kelvin pin (4-lead), are faster than traditional three-terminal MOSFETs (3-lead). Moreover, the former presents a lower increment in the turn-on power losses as the load increases. This paper investigates the phenomenon and explains this behavior. The drain-source voltage waveform of the 3-lead device usually presents a plateau due to the voltage drop across the parasitic inductances during the current rising and to the clamp imposed by the diode until it conducts. The higher current speed of 4-lead involves that the plateau should occur at a lower value of the drain-source voltage, then this voltage takes longer to reach this lockout value. On the other hand, the higher current speed involves a reduced time necessary for the 4-lead device to reach the boost inductor current, thus unclamping earlier the diode. Consequently, the plateau does not occur thus achieving reduced turn-on losses. The plateau extension is small in the 3-lead MOSFET at low current and it increases as the current increases, thus the advantage increases as the current increases. The formulation and argumentation supporting the understanding of this phenomenon can be applied also to faster power devices like the SiC MOSFET and the GaN HEMT.

Nowadays, there is a great research effort in the field of electric vehicles. In such a context, SiC power modules play a key role for their effective and widespread diffusion especially due to their ability at improving the performance of the traction inverter. The advantages and issues related to SiC traction modules are analysed in this work giving also guidelines for viable solutions. More specifically, electrical and thermal problems, safety and reliability issues, challenges from device paralleling and module layout as well as power efficiency, have been investigated. The aim of this work is to collect all these aspects that must be carefully considered at the SiC power modules design stage. The main merit of this overview is their analysis performed by means of on field experience, in terms of experimental tests, finite element analysis, and circuit simulations.

The Si devices have achieved their theoretical limits with the increasing of the switching frequency. The innovative GaN power switches present many advantages in power conversion systems, especially in terms of efficiency and size. The use of GaN transistors will be strongly exploited in the automotive applications due to these features. Indeed, the socalled point of loads require an increasing attention, in particular for the 48V-12V electric system architectures. In this paper the reduction of the energy losses achievable thanks to commercial GaN devices is analyzed by a simple circuit model. The effectiveness of the model is validated by experimental measurements in a synchronous buck converter. The results confirm that a remarkable efficiency improvement with the current GaN technology may be already reached.

Nowadays, the light-emitting diode (LED) bulb is one of the preferred choice in lighting system design. Electrical models of the LED lamps have to consider their nonlinear behavior involving current distortion on the mains. With this purpose, an equivalent electrical circuit emulating the current drawn by a LED Bulbs is carried out. In this work, different lamps have been tested under variable supply voltage. The comparison between the simulations performed by means of PSpice and the experimental measurements has highlighted that linear interpolation for the amplitude of each harmonic current, as function of the voltage on the main, provides a good estimation of the total current waveform.

Super junction (SJ) MOSFET is a well-established device in high-density and high frequency power conversion. Soft-switching techniques are usually adopted at high frequency to reduce the power losses into the power devices. However, new challenging issues appear always when the paradigm changes. In fact, unexpected heating and efficiency reduction due to Coss related phenomena are key issues to be faced when SJ MOSFETs are adopted in high-frequency soft-switching applications. The phenomenon appears when large voltage transients are applied to the drain-source terminals as in the case of soft-switching applications. This paper provides analysis of the electrical hysteresis, and proposes an equivalent circuit that may model such a behavior in case of SJ MOSFETs. The loss model of Coss has been validated by comparing the measurements with the simulation runs performed by means of the Simulink package.