Marcelo Schupbach

High Switching Performance of 1700-V, 50-A SiC Power MOSFET Over Si IGBT/BiMOSFET for Advanced Power Conversion Applications

Due to wider band gap of silicon carbide (SiC) compared to silicon (Si), MOSFET made in SiC has considerably lower drift region resistance, which is a significant resistive component in high-voltage power devices. With low on-state resistance and its inherently low switching loss, SiC MOSFETs can offer much improved efficiency and compact size for the converter compared to those using Si devices. In this paper, we report switching performance of a new 1700-V, 50-A SiC MOSFET designed and developed by Cree, Inc. Hard-switching losses of the SiC MOSFETs with different circuit parameters and operating conditions are measured and compared with the 1700-V Si BiMOSFET and 1700-V Si IGBT, using same test set-up. Based on switching and conduction losses, the operating boundary of output power and switching frequency of these devices are found out in a dc-dc boost converter and compared. The switching dv/dts and di/dts of SiC MOSFET are captured and discussed in the perspective of converter design. To validate the continuous operation, three dc-dc boost converters using these devices, are designed and tested at 10 kW of power with 1 kV of output voltage and 10 kHz of switching frequency. 1700V SiC Schottky diode is used as the blocking diode in each case. Corresponding converter efficiencies are evaluated and the junction temperature of each device is estimated. To demonstrate high switching frequency operation, the SiC MOSFET is switched upto 150 kHz within permissible junction temperature rise. A switch combination of the 1700-V SiC MOSFET and 1700-V SiC Schottky diode connected in series is also evaluated for zero voltage switching turn-ON behavior and compared with those of bipolar Si devices. Results show substantial power loss saving with the use of SiC MOSFET.

Dynamic and static behavior of packaged silicon carbide MOSFETs in paralleled applications

There is little work done to study the nuances related to paralleling the higher speed SiC Mosfet devices when compared to Si devices. This paper deals with the parallel operation of packaged silicon carbide (SiC) MOSFETs. The parameters that affect the static and dynamic current sharing behavior of the devices have been studied. We also investigate the sensitivity of those parameters to the junction temperature of the devices. The case temperature difference for paralleled MOSFETs has been experimentally measured on a SEPIC converter for different gate driver resistance and different switching frequency, the results show the current and temperature can be well balanced for the latest generation of SiC MOSFETs with low gate driver resistance.

Static and dynamic performance characterization and comparison of 15 kV SiC MOSFET and 15 kV SiC n-IGBTs

This paper presents the static and dynamic performance of 15 kV SiC IGBTs with 2 um and 5 um field-stop buffer layer thicknesses respectively and compares them with 15 kV SiC MOSFET in term of loss and switching capability. Their switching energy for different gate resistors and temperature have been reported and compared. A 5 kHz 10.5 kW 8 kV boost converter has been built and tested using these three devices respectively. The MOSFET based boost converter has the highest efficiency 99.39% which is the highest reported efficiency for a high voltage SiC device based converter. PLECS loss models can be developed for these devices based on the characterization data to simplify the simulation of a variety circuits or applications which potentially utilize these devices.

High switching performance of 1.7kV, 50A SiC power MOSFET over Si IGBT for advanced power conversion applications

Silicon Carbide (SiC) has wider band gap compared to Silicon (Si) and hence MOSFET made in SiC has considerably lower drift region resistance, which is a significant resistive component in high-voltage power devices. Due to low on-state resistance combined with its inherently low switching loss, SiC MOSFET is an excellent candidate for high power converter design. With its lower power loss and operation capability at higher switching frequency, power converters based on SiC MOSFETs can offer much improved efficiency and compact size compared to those using Si IGBTs. In this paper, we report switching performance of a new 1.7kV, 50A SiC MOSFET; designed and developed by Cree, Inc. Hard-switching losses of the SiC MOSFETs with different circuit parameters and operating conditions are measured and compared with the 1.7kV, 50A Si IGBTs, using the same test setup. Switching performance of the 1.7kV SiC MOSFET and 1.7kV SiC Schottky diode connected in series are also evaluated under a zero current switching (ZCS) condition and important findings are reported.

High voltage, high power density bi-directional multi-level converters utilizing silicon and silicon carbide (SiC) switches

This paper presents a bi-directional ac-dc isolated converter designed to be utilized within the US Navys Integrated Fight Through Power (IFTP) concept. To demonstrate the proposed approach the authors have designed, fabricated, and tested a 20 kW power conversion module (PCM) prototype. The fabricated PCM module was used to demonstrate the proposed overall electrical design approach, high-frequency isolation, bi-directional power flow and soft-switching operation of the quasi-resonant topologies. Moreover, the 20-kW prototype allowed the verification of control methodologies as well as magnetic and thermal designs, and provides a test bed for future, higher power work.

High performance, large-area, 1600 V / 150 A, 4H-SiC DMOSFET for robust high-power and high-temperature applications

In this paper, we report our recently developed 2^nd Generation, large-area (56 mm² with an active conducting area of 40 mm²) 4H-SiC DMOSFET, which can reliably block 1600 V with very low leakage current under a gate-bias (V_G) of 0 V at temperatures up to 200°C. The device also exhibits a low on-resistance (R_ON) of 12.4 mΩ at 150 A and V_G of 20 V. DC and dynamic switching characteristics of the SiC DMOSFET have also been compared with a commercially available 1200 V/ 200 A rated Si trench gate IGBT. The switching energy of the SiC DMOSFET at 600 V input voltage bus is > 4X lower than that of the Si IGBT at room-temperature and > 7X lower at 150°C. A comprehensive study on intrinsic reliability of this 2^nd generation SiC MOSFET has been performed to build consumer confidence and to achieve broad market adoption of this disruptive power switch technology.

SiC intelligent multi module DC/DC converter system for space applications

Power electronic converters are essential in every mission vehicle, with use in critical systems ranging from electric power management applications, to power distribution, to on-board servo motor/actuator drivers. Power converter systems are restricted by their maximum operating voltage and current (and hence power) levels at both their inputs and outputs. Scalability to a higher voltage, current or power level means a complete redesign of the power converter system—an expensive, time consuming process. Increasing power density and efficiency, reducing size and weight, and introducing standardization of electronics systems are all goals of the aerospace industry. The modular converter concept is an ideal solution to diminish time and expenses associated with the implementation of typical converters. However, true modular operation of DC/DC converters presents a set of inherent power sharing problems derived from their intrinsic topology behavior and closed loop control characteristic. An advanced silicon carbide (SiC) based intelligent multi module DC/DC converter system has been designed, built, and tested.

Initial development of a solid-state fault current limiter for naval power systems protection

For the protection of electric ship distribution systems, it is desired that a system be developed which can limit fault currents to reasonable values and which can act more quickly, more reliably, and with a smaller form factor than conventional approaches. Arkansas power electronics International, Inc. (APEI) is currently collaborating with researchers at the University of Arkansas (UA) to develop a solid state fault current limiter/interrupter (SSFCL) which is believed to be capable of outperforming conventional approaches. This paper summarizes the current status and objectives of this work at the time of submission.

High Temperature Silicon Carbide Power Modules for High Performance Systems

The demands of modern high-performance power electronics systems are rapidly surpassing the power density, efficiency, and reliability limitations defined by the intrinsic properties of silicon-based semiconductors. The advantages of silicon carbide (SiC) are well known, including high temperature operation, high voltage blocking capability, high speed switching, and high energy efficiency. In this discussion, APEI, Inc. presents two newly developed high performance SiC power modules for extreme environment systems and applications. These power modules are rated to 1200V, are operational at currents greater than 100A, can perform at temperatures in excess of 250 °C, and are designed to house various SiC devices, including MOSFETs, JFETs, or BJTs.

Characterization of SiC JFETs and its Application in Extreme Temperature (over 450°C) Circuit Design

In order to facilitate the circuit design and simulation at extreme temperatures, APEI, Inc. fully characterized a custom-built SiC VJFET transistor at temperatures up to 525 °C and built a Spice model based on the characterization data. The temperature effects were also formulized in this Spice model to ensure its uniform applicability over the entire temperature range. Test circuits of a differential amplifier and a multivibrator were built and tested from room temperature up to 450 °C to validate the proposed SiC JFET model, which could be widely applied in Spice based circuit simulation packages.