This article details the conception of an inverter leg with vertical interconnection and integrated shielding based on silicon MOSFET. Shields with constant voltage bias are used to shield semiconductors in order to minimize values of common mode capacitor. It allows to reduce common mode coupling. Shielded and unshielded inverter legs are compared and a reduction of the common mode current was observed up to -10dB with a shielded packaging. Printed circuit boards (PCBs) are used as dielectric substrates and electrical conductors. A discussion on the relevance of this structure for vertical WBG power components is presented.

Current sensing plays an important role in power electronics, for both protection and control of power electronic converters. This paper proposes an approach for detecting short-circuit (SC) events through the measurement of the magnetic field radiated by power converters. Two magnetic field sensor technologies (AMR sensor and induction coil) were evaluated. The induction coil system achieves a frequency bandwidth of 20 MHz with simple signal conditioning, whereas the AMR system is limited to about 1 MHz and requires more complex electronic conditioning. Magnetic field mapping over the printed circuit board (PCB) was performed to identify favorable positions for SC detection. Contactless current sensing was then evaluated on an EPC evaluation board based on GaN transistors. The results demonstrate that induction coil is a promising solution, not only for SC event detection but also for contactless current measurement in power converters. This work contributes to the development of integrated contactless current sensors for power converters or for intelligent gate drivers with SC or overcurrent protection integrated, especially dedicated to wide-bandgap devices such as GaN and SiC transistors, which often exhibit lower SC robustness compared to silicon devices.

This article presents a method for evaluating the initiation of delamination at a corner of a solder joint in a 3D power electronics assembly of SiC MOSFETs on a PCB (printed circuit board) substrate. This development is part of an effort to assess the robustness of technological choices for a new model of wide bandgap component assembly. These assemblies consist of a PCB substrate (layers of copper, epoxy, and glass fibers) and a soldered copper block corresponding to the heat-sink base-plate. However, conventional methods do not effectively meet the need for detecting the initiation of solder delamination for the assembly design. The method relies on potential measurements that exhibit greater sensitivity to detect the onset of solder delamination than conventional method. Finite element simulations are carried out to evaluate of the method’s sensitivity and discriminating factors such as geometry and materials involved. Based on the numerical results, dedicated prototypes of the assembly are manufactured with control of delamination initiated at a corner of the solder joint. Confrontation of experimental results and numerical studies offers good perspective as a complementary method to detect the delamination initiation propagation of joining technologies.

The accurate estimate of power losses is of the first importance for power electronic design. This paper presents a test bench based on the opposition method and the calorimetric method used to characterize the losses of SiC MOSFET modules. Electronic instrumentation is implemented to accurately measure the differential temperature, the flow rate, the water pressure and the current. To minimize the stray inductance, the power circuit is designed in the form of busbars. The first experimental tests will focus on the calibration of the new measurement system and try to estimate the various factors that influence the accuracy of the power losses measurements.

Power cycling test is the major reliability test method of conventional power modules due to temperature stress. In recent years new packaging technologies based on embedding active dies on the Printed Circuit Boards (PCB) are proposed. However, the reliability of these new technologies must be assessed. In this paper, experimental investigations on the already proposed solderless packaging in which connections are made using a pressed metal foam are presented. To assess the later packaging reliability, the devices have been subjected to power cycling conditions. Failure analysis have been made revealing degradations in the PCB interfaces.

The fourth-generation corrector electromagnets of the SOLEIL synchrotron require compact switch mode power supplies (SMPS) with high dynamics in the transition phases, low residual output ripple of few ppm, good EMC performance and good efficiency. To achieve this, the study of a low-power bipolar DC-DC converter with a high switching frequency is in progress. A technological comparison between GaN HEMT and Si MOSFET based SMPS is proposed on the different criteria of the specifications.

Electroactive polymers show promising characteristics, such as lightness, compactness, flexibility, and large displacements, making them a candidate for application in cardiac assist devices. This revives the need for quasi-square wave voltage supply switching between 0 and several kilovolts, that must be efficient, to limit the heat dissipation, and compact in order to be implanted. The high- access resistance, associated with compliant electrodes, represents an additional difficulty. Here, a solid-state Marx modulator is adapted to cope with electroactive polymer characteristics, taking advantage of an efficient energy transfer over a sequential multistep charge/discharge process. To ensure compactness, efficiency, as well as the needs of an implanted device, a wireless magnetic field-based communication and power transfer system has been implemented. This work demonstrates the benefit of this design through simulations and experimental validation on a cardiac assist device. At a voltage of 7 kV, an efficiency of up to 88% has been achieved over a complete charge/discharge cycle.

This article presents local shielding techniques applied to a half-bridge inverter leg with the aim to reduce the common-mode (CM) current noise at converter’s dc input. The research study is conducted for 650-V enhancement mode Gallium Nitride power transistor switches. Main contributors of parasitic capacitances referred to the inverter-leg middle point node are identified. Then, shielding solutions are proposed to reduce the CM current emission by these capacitances. Respecting the precautions concerning the isolation of CM currents of the half-bridge inverter leg, the electromagnetic compatibility measurement setup is developed. Experimental step-by-step addition of local shielding copper layers to different contributors of middle point capacitance shows progressive attenuation of CM noise spectra.

This work is based on an innovative converter structure for an automotive application. A major constraint is the cooling. A nondimensionalization and an analytical resolution of a thermal problem applied to power electronics are proposed. A study of the influence of the geometrical parameters on thermal resistance is carried out to understand the underlying phenomena. Two sizing methods are proposed, based on charts calculated from the proposed resolution. An example of an application based on the initial problem is presented and compared to a finite element simulation.

This paper deals with the design of the magnetic component of an isolated bidirectional multiportconverter. This converter is intended to be embedded in an autonomous surface marine vehicle with a power rating in the kilowatt range and is intended to exchange power between photovoltaic panels, a lithium battery and the propulsion system in which the motors can also be operated as a tidal turbine. This magnetic component is a three-port symmetrical three-phase transformer that allows to interface three three-phase inverters with a six-step control. The converter is galvanically isolated and can operate in a fully bi-directional way. Phase shifting of the inverters allows the power flow between them to be adjusted.

In the perspective of upgrading the SOLEIL synchrotron accelerators, new electromagnet power supplies utilized for the control of the electron beam trajectory are being studied. For those implemented in the fastest beam orbit feedback loop, a new generation of low voltage, high frequency DC-DC converters based on Gallium Nitride (GaN) High Electron Mobility Transistors (HEMTs) is envisaged. One of the crucial points of their design concerns the routing of the switching cells, which is critical with respect to Electromagnetic Compatibility (EMC) and surge voltages, thus requiring a preliminary investigation. For this purpose, a routing model using the Ansys Q3D software is studied in this paper. The data from the Q3D simulation are compared to the experimental results for the prediction of the EMC performance of the DC-DC full-bridge converter. The EMC model resulting from this study allows analyzing the influence of the inter-cell parasitic inductances on the levels of the disturbances conducted in common and differential mode.

This paper investigates how the optimized volume of an EMC filter is affected if the levels of standards are modified. Firstly, an algorithm for designing passive EMC filters with optimized volume has been developed. Then, based on this algorithm several filters have been designed. The filter’s volume variations against the variations of standard level are then discussed.

This paper presents a study and comparison in terms of magnetic circuit sizing for two magnetic coupling topologies for interleaved multilevel inverters: the cyclic cascade and the secondary loop. This comparison includes modeling of both topologies and simulation analysis of the sizing of each of them. The interleaved multilevel inverter is then simulated with the sized magnetic components for the system operating point for both topologies. Then, a secondary loop improvement study is developed and simulated to minimize the sizing current for this topology. Finally, an experimental test bench is presented to test and analyze the experimental results for both topologies for a measurement power point of 10 kW.

This paper presents an original methodology and a test bench for active power cycling and on-line junction temperature measurement during power cycling of power devices embedded in PCB. This method is based on the use of the ratio between forward voltage and forward current variations (∆VF,∆IF) during conduction period to estimate the thermal voltage UT and thus the junction temperature in real time. The objective of this study is to estimate the junction temperature even for high frequency of power cycling tests. First, the measurement method is presented, and then the test bench is described.

This study proposes a comprehensive analytical model of the magnetism, electrostatics, and loss mechanisms of a simple and economical structure with a printed circuit board-embedded magnetic component (coil, high leakage transformer, or resonator) for electric power conversion in the range 1 W-100 W. The predictions of this model are compared to finite element simulations. A good match is obtained over a wide bandwidth (up to at least 10 MHz). The model is adapted to predict the electrical characteristics of the device used as a monolithic series-LC tank, with a resonant frequency in the MHz range. A prototype is built to prove the applicability of the model, which is intended for the design and optimisation of power electronics converters. (C) 2020 International Association for Mathematics and Computers in Simulation (IMACS). Published by Elsevier B.V. All rights reserved.