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Online Junction Temperature Extraction of SiC Power MOSFETs with Temperature Sensitive Optic Parameter (TSOP) Approach
摘要： Accurate information of the junction temperature of SiC power MOSFETs ensures safe operation and helps reliability assessment of the devices. In this paper, an online junction temperature extraction method is proposed based on the electroluminescence phenomenon of the body diode of SiC power MOSFETs. It is found that during the forward conduction interval of the body diode, visible blue light is emitted around the chip, which ascribes to the radiative recombination in the low doped region of SiC MOSFETs. Experimental results suggest the light intensity changes linearly with the variation of the temperature and behaves as a temperature sensitive optic parameter (TSOP). Further, an electro-thermal-optic model is proposed to reveal the relationship between electroluminescence intensity, forward current and junction temperature. Based on the TSOP, an online junction temperature extraction method is proposed for SiC MOSFETs and verified in a SiC MOSFET based inverter. Compared with state-of-the-art methods, the proposed junction temperature measurement method is contactless and immune from the aging of the package.
关键词： junction temperature extraction,Body diode,thermal management,electroluminescence,SiC MOSFETs
更新于2025-09-23 15:22:29
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[IEEE 2019 International Semiconductor Conference (CAS) - Sinaia, Romania (2019.10.9-2019.10.11)] 2019 International Semiconductor Conference (CAS) - Voltage Controlled Oscillator for Small-Signal Capacitance Sensing
摘要： SiC MOSFETs are applied to constitute a three-phase, 5-kW LLC series resonant dc/dc converter with isolation transformers. A switching frequency of around 200 kHz for the transistors successfully reduces the volume of these isolation transformers, whereas insulated-gate bipolar transistors (IGBTs) are not capable of achieving such a high switching speed. The high-voltage tolerance of SiC MOSFETs, 1200 V, enables increasing the input voltage up to 600 V. High-voltage tolerance, on the other hand, is not compatible with low on-resistance for Si MOSFETs. A three-phase circuit topology is used to achieve up to 5 kW of power capacity for the converter and reduce per-phase current at the same time. Current-balancing transformers among these three phases effectively suppress a maximum peak current from arising in the circuit, a technique that miniaturizes the input and output capacitances. The conversion efficiency of the converter reaches 97.6% at 5-kW operation.
关键词： SiC MOSFETs,zero-voltage switching (ZVS),Current-balancing transformers,zero-current switching (ZCS),three phase,LLC resonant converter
更新于2025-09-19 17:13:59
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[IEEE 2018 IEEE 6th Workshop on Wide Bandgap Power Devices and Applications (WiPDA) - Atlanta, GA, USA (2018.10.31-2018.11.2)] 2018 IEEE 6th Workshop on Wide Bandgap Power Devices and Applications (WiPDA) - Short Circuit Ruggedness of New Generation 1.2 kV SiC MOSFETs
摘要： New generations of silicon carbide (SiC) based MOSFETs are commercially available from manufacturers featuring smaller chip size with higher power density demonstrating performance improvement compared to their previous generation counterparts. As the size of the chip is small, the volume available to dissipate energy during short-circuit (SC) like conditions is reduced, leading to increased self-heating of the device. Therefore, the short circuit withstand time (SCWT) is reduced. As a reliability aspect, ruggedness to extreme operating conditions like SC needs to be analyzed for these devices, to improve the design or to design better detection and protection circuits for these MOSFETs when used in specific SC vulnerable applications. In this work, the new third generation 1.2 kV SiC MOSFET from Wolfspeed in a TO-247-4 pin package having a smaller chip size is measured for SC ruggedness. The causes for device failure under different DC-link voltages, gate bias voltages, SC pulse durations and self-heating behavior are analyzed based on the destructive SC tests performed. The device is measured to have an SCWT of 2 μs at a DC-link voltage of 800 V compared to SCWT of 4.5 μs for the second generation 1.2 kV devices with larger chip size and TO-247-3 pin package. The presence of the Kelvin source contact demonstrates higher peak SC currents compared to the same devices without Kelvin source.
关键词： short-circuit ruggedness,SiC MOSFETs,Kelvin source contact,self-heating,failure analysis
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE 6th Workshop on Wide Bandgap Power Devices and Applications (WiPDA) - Atlanta, GA, USA (2018.10.31-2018.11.2)] 2018 IEEE 6th Workshop on Wide Bandgap Power Devices and Applications (WiPDA) - Power Cycling of Commercial SiC MOSFETs
摘要： The robustness under power cycling of three comparable silicon carbide MOSFETs in TO-247 packages from three different manufacturers is investigated, with silicon IGBTs serving as reference. The power cycling method, especially the junction temperature measurement and best practices to ensure its accuracy, is described. The results give insight into reliability and variability as well as aging behavior and failure modes. We ?nd a large variability between samples, both in initial characteristics and measured cycling lifetime, as well as signs of semiconductor device degradation. There is a signi?cant spread in the extent of the variability, in the average and minimum observed lifetime, as well as in the failure mode. Some samples fail quickly due to bond wire defects, some due to semiconductor degradation, while others show very long lifetimes.
关键词： power cycling,SiC MOSFETs,variability,reliability,aging behavior,failure modes
更新于2025-09-04 15:30:14
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99 % Efficient 10 kV SiC-Based 7 kV/400 V DC-Transformer for Future Data Centers
摘要： The power supply chain of data centers from the medium voltage (MV) utility grid down to the chip level voltage consists of many series connected power conversion stages and accordingly shows a relatively low ef?ciency. Solid-State Transformers (SSTs) could improve the ef?ciency by substantially reducing the number of power conversion stages and/or directly interfacing the MV AC grid to a 400 V DC bus, from where tens of server racks with a power consumption of several kilowatts could be supplied by individual SSTs. The recent development of SiC MOSFETs with a blocking voltage of 10 kV enables the realization of a simple and hence highly reliable two-stage SST topology, consisting of an AC/DC PFC recti?er and a subsequent isolated DC/DC converter. In this context, an isolated 25 kW, 48 kHz, 7 kV to 400 V series resonant DC/DC converter based on 10 kV SiC MOSFETs is realized and tested in this paper. To achieve zero voltage switching (ZVS) of all MOSFETs, a special modulation scheme to actively control the amount of the switched magnetizing current on the MV and LV side is implemented. Furthermore, the design of all main components and especially the electrical insulation of the employed medium frequency (MF) transformer is discussed in detail. Calorimetric ef?ciency measurements show that a full-load ef?ciency of 99.0 % is achieved, while the power density reaches 3.8 kW/L (63 W/in3).
关键词： ZVS,isolated DC/DC,medium-voltage transformer,10kV SiC MOSFETs,soft-switching,Medium-voltage,calorimetric measurement
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE 6th Workshop on Wide Bandgap Power Devices and Applications (WiPDA) - Atlanta, GA, USA (2018.10.31-2018.11.2)] 2018 IEEE 6th Workshop on Wide Bandgap Power Devices and Applications (WiPDA) - A Voltage-Edge-Rate-Limiting Soft-Switching Inverter for Wide-Bandgap Devices
摘要： Wide-bandgap (WBG) switches can achieve switching times on the order of several nanoseconds. However, faster switches generate larger inverter output dv/dt. Various deleterious effects attributed to large inverter dv/dt have been observed in various applications, especially in motor drive systems. The effects include false turn-on of WBG switches due to cross-talk, transient over-voltages at motor terminals, electromagnetic interference, and motor bearing failures due to micro arcs. A common approach for limiting peak inverter dv/dt involves the insertion of a dv/dt filter. However, the dv/dt filter introduces extra power losses and increases the size/weight of the heat sink. Soft-switching circuits can reduce inverter dv/dt and switching losses, but using soft-switching to accurately control dv/dt has not been fully explored. A new soft-switching circuit, entitled the auxiliary resonant soft-edge pole (ARSEP), is set forth. The ARSEP improves the available soft-switching circuits so that the dv/dt can be accurately controlled through circuit parameter design. An ARSEP inverter prototype based on SiC MOSFETs was designed, simulated, built, and tested to verify its performance and benefits. Compared to a conventional hard-switched inverter with a dv/dt filter, the ARSEP inverter results in a significant reduction in overall power loss, inductor volume, and weight.
关键词： SiC MOSFETs,soft-switching circuits,auxiliary resonant soft-edge pole (ARSEP),inverter output dv/dt,Wide-bandgap (WBG) switches
更新于2025-09-04 15:30:14