Search

This article presents the analysis and management of differential mode conducted EMI in modular converters made from associations of standard conversion cells. Two main configurations, inputs in series—outputs in parallel and inputs in parallel—outputs in series are studied with the objective to define a generic EMI management technique, independent from the number of conversion standard cells implemented. First, analysis is carried out from a theoretical point of view based on simplified models. Second, filtering solutions are introduced and compared. Especially, centralized versus distributed filtering techniques are compared with the objective to find generic solutions. The results are compared and validated with practical characterizations. [ABSTRACT FROM AUTHOR]

In a resonant dc/dc converter, the major part of the volume is filled by passive components. Moreover, all these components have to support all the power flow. On the one hand, this leads to losses in these components and their connections and on the other hand to an important cost of the converter. Concept of integrated passive component, called inductor-capacitor-transformer (L-C-T), is now well known [1], [3], [4], [6], [8] and this paper will present a new prototype which permits to integrate in an unique part an inductor, a capacitor and a transformer. Because it uses only one core with three windings, this component will reduce the volume of the passive part of the converter. By reducing the number of connections it will, also, have a positive effect on losses. After a presentation of L-C-T components, this paper describes a design of this device, using new windings disposition. The proposed structure permits to adjust separately L and C values. Then, to validate the approach, a characterization is carried out, leading to a new model, including dielectric, iron and copper losses. [ABSTRACT FROM AUTHOR]

This paper deals with the design and the implementation of an isolated and highly integrated low voltage, low power microconverter. A dual active-bridge topology is considered as a good candidate for reducing the number of passive elements. The design of a “power die” integrating power inverter legs and their driver circuits is carried out in order to benefit from the high level of integration and to reduce the amount of active components and the volume of the converter. Thus, a microconverter is built for 10 W power supply (5 V/2 A) and is operating at 1 MHz switching frequency. The measured efficiency of the converter is 88% for 6.5 W transferred power and 86% for 8.5 W transferred power without taking into account its control unit. The converter is operating in natural convection, and no cooling system is implemented. Therefore, a power density of 9.9 kW/L is achieved, which is beyond the state of the art of the conventional isolated converters whose power densities are around 1–2 kW/L at the same power level. [ABSTRACT FROM AUTHOR]

This letter introduces a self-oscillating very high-frequency (VHF) class $\phi$ 2 inverter based on a free-running oscillator. The class $\phi$ 2 is a low-voltage semiconductor stress, fast-transient, single-transistor inverter topology suitable for VHF applications. With new advancements in GaN technology, the tendency to increase the switching frequency in power converters is on the rise. Switching at VHF (VHF: 30–300 MHz) allows for smaller passive components and more compact power converters. However, although GaN components are able to switch at 100 MHz and beyond, gate drivers available in the market struggle to provide the adequate switching signal at VHF. Hence, there is a need for an alternative to VHF converters using those gate drivers—self-oscillating topologies. To that end, a self-oscillating class $\phi$ 2 inverter switching at 30 MHz is presented and a design methodology is provided. A 30 MHz prototype with 30 V input voltage using a GaN Systems GS61004B is also built and tested, showing good matching between the simulation and experimental results. [ABSTRACT FROM AUTHOR]