Products & Applications Major advances in silicon and wide-bandgap devices
Wide-bandgap was without a doubt the hot topic at PCIM Europe (May 7-9, 2019 in Nuremberg). However, manufacturers also showcased a variety of innovative power devices, ranging from transducers to converters. In this article, we'll go through some of the highlights from the fair.
Whoever fears that there will be no new advances in the silicon components’ industry in the coming years can breathe out. Infineon introduces a new 550-A/3300-V half-bridge module with IGBT4 and .XT-technology in the so-called XHP3 package. It increases power density and load cycling life for high power converters. The current carrying capacity of the module increases from 450 A to 550 A for the same footprint. In terms of footprint, this is 7,86 A/cm2.
The voltage class 3.3 kV results in a power density of 25.94 kW/cm2. Since the thermal resistance has also been improved, Infineon estimates that the output current in the motor drive can be increased by 30% to 40% using the new technology. In addition, this package offers very high reliability due to the .XT-technology with sintered chips; compared to the state of the art, the load cycle strength increases by a factor of 5.
Competition from China: CRRC Times Electric Co., Ltd/China presents an 1800-A/3300-V-E2-IGBT with TMOS+IGBT at PCIM Europe. It uses trench technology with matched non-contacted dummy trench structures as shown in Figure 2.
This technology makes it possible to significantly reduce conduction and switching losses. The switch-off capability of 6.5 times overcurrent is shown; this is a record. So far, the switch-off capability of 3 to 4 times the rated current has been demonstrated. The freewheeling diode is also optimized, its switching behavior is oscillation-free even with low currents and high DC link voltage. CRRC is, therefore, focusing on new ideas and is becoming a new player in the first league of progress in IGBTs.
Even higher power density with silicon carbide
Hitachi introduces a 3.3 kV 1000 A high-performance silicon carbide module. As shown in Fig. 3, the module has a full-bridge; the footprint of 100 mm x 140 mm is the same, only the connection configuration has changed.
Cu-sintering is used as the technology for high reliability.
A module with currently the highest power density
The module is specified to 2 x 1000 A, so it carries 14.28 A/cm2. With 3.3 kV follows a power density of 47 kW/cm2. "This is an increase of 25 percent compared to the state of the art and, as far as published so far, it is the module with the highest power density in the world," the authors write. Due to the same area, we can compare it with the module in Figure 1, which allows a comparison of Si-IGBT and SiC-MOSFET with respect to the achievable power density. In the SiC module, the inverse MOSFET diodes are used as free-wheeling diodes, in the operation of the inverse diode, the work is planned as synchronous rectifier with positive voltage at the gate. The comparison of overload capability and robustness is now highly interesting.
New developments in gallium nitride devices
Interesting new advances have also been made in GaN power semiconductors: Panasonic introduces a GIT transistor, in common lateral structure, but manufactured on a GaN substrate instead of GaN-on-Si, which is currently used. The mismatch between GaN and Si, which is now a thing of the past, improves the component properties: significantly higher blocking capability, 45% lower on-resistance, explainable by the greatly reduced density of dislocations.
Also from Panasonic is a bidirectional switch from GaN. The simplified structure is shown in Figure 4. The component is barrier and conductive in both directions and has two gates.
Products & Applications
MOSFET driver: a common cause of failure
A supporting programme rounded off the conference
At the PCIM Europe from 07.-09.05.2019 in Nuremberg both well-known industry leaders and smaller, specialized companies presented their products and components on the exhibition floor. Among other things, trade visitors expected innovations from the areas of power semiconductors and passive components, which were offered by 39% and 38% of the exhibitors respectively, as well as from the topics of thermal management (25%) and power electronic converter systems (21%). In total, more than 500 exhibiting companies presented their products and services, more than half of them from abroad.
Both at the three trade fair forums and within the framework of the application-oriented conference, PCIM Europe offered a top-class lecture programme with contributions on topics such as "The Evolution of GaN" (Power Systems Design), "EV/HEV Transformation of the Power Modules Industry" (Yole Développement) and "Thermal Resistance of Interconnect Layers in Inverter Power Stack Assembly" (Alpha Assembly Solutions). Under the motto "Meet the Speaker", all speakers will be available for questions at the technical and e-mobility forums following their presentations.
For the first time, guided tours to the stands of specialized exhibitors took place at E-Mobility, for which interested trade visitors were able to register in advance of the event. In addition to the exchange of knowledge and experience, seven user-oriented seminars and ten tutorials in exclusive group sizes with renowned experts offer insights into future technologies at PCIM Europe. Edward Shelton, University of Cambridge, gave a full-day tutorial on "WBG Devices, Circuits and Measurement".
This article was first published in German by Elektronikpraxis.
* Prof. Dr. Josef Lutz lectures at the TU Chemnitz and is an advisory member of the Board of Directors of PCIM Europe.