## 1 Introduction  
Power converters are key players toward decarbonation of our modern societies contributing, for example, to the effective usage of electrical energy in most motor drive applications such as mobility, air conditioning, home appliances... For many years, research and developments are focused on increasing the efficiency, power density and reliability of power converters, working on materials, components, topologies and control strategies. Nowadays, most power converters have reached excellent efficiency levels such as in PV applications with converter efficiency ranging from 96 to 98% [1; 2; 3]. Also, converters with very high-power densities are available. For example, three-phase Voltage Source Inverters (VSI) have power densities above 30 kW/ L [4]. Nonetheless, the quest to improve further the tradeoff between efficiency and power density remains a specification driver for the domain. It is well admitted that the power density of power converters is mostly impacted by cooling needs as well as energy storage needs. On one side, cooling is required to remove the generated heat produced by the power converter under operation. The higher the efficiency and/or the maximum operating temperature of components, the smaller the cooling needs. The recent great progress on active devices, with the introduction of Wide-Band Gap (WBG) materials and components, has introduced a shift toward higher Figure Of Merits (FOM) and higher maximum operating temperature, opening the door for drastic cooling needs reduction, even at higher switching frequencies [5; 6]. On the other side, energy storage in power converters is necessary to smooth and filter the voltage and current waveforms chopped by the switching cells to pattern the power flow. Regardingpassive components, if significant progress has been reached toward better design, materials and manufacturing technologies, a disruptive shift has still not been identified since the introduction of ferrite materials. It is well known that a key driver to increasing power density is to increase the apparent switching frequencies of power converters. This can be obtained thanks to multicell interleaved converters such as in [7; 8]. Or it can be obtained more classically by increasing the switching frequency of the power converter. If, with the introduction of WBG devices, the increase in switching frequency can be performed at no cost in terms of extra switching losses, on the passive components side, the quest for increasing the switching frequency is not always a success in terms of efficiency. This is mostly due to skin effects that increase Joules losses as well as extra core/iron losses as described in Section 3 of [9]. The impact of the frequency on the extra losses to be produced remains a difficult issue to be precisely estimated during the design process. Indeed, the design methodologies have a limited ability to estimate precisely the impact of switching frequency increase on passive component losses. For power electronics (PE) converter designers, optimizing the switching frequency with respect to efficiency remains a difficult task since no accurate data or model, made available from the component manufacturers, is able to deliver a representative estimate of the magnetic device losses with respect to the actual signal shape and frequency applied to the component. As a consequence, many designers are reluctant to increase switching frequency and/or the ripple voltage and current applied to passive components because their high-frequency behaviour is not easy to forecast. In buck-derived converters such as the chopper or the voltage source inverter (VSI) illustrated in Figure 1, this may lead to a large value and size for the output inductor(s). This paper is investigating the relevance to consider the design procedure only from existing parts, trying to develop a full set of data and models directly from experiments and characterization.