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关键词： SiC MOSFET   power semiconductor   junction temperature smoothing control   electric vehicle motor drive inverter   body diode   conduction loss  

摘要： In a converter of actual working condition, the change in the current and voltage of the power device will cause the junction temperature to fluctuate greatly. This device is subjected to high thermal stress due to the change in the junction temperature. Therefore, it is necessary to adopt junction temperature control to reduce or smooth the junction temperature fluctuation, so as to realize the junction temperature control and improve the reliability of the device. At present, the methods for the junction temperature control of power devices have certain limitations and there are few active thermal management methods proposed for SiC device characteristics. In this paper, a method for realizing the smooth control of the junction temperature of a SiC device based on the conduction loss adjustment of the body diode for the SiC device has been proposed, considering that the conduction loss of the body diode is greater than the conduction loss of the SiC MOSFET. The conduction time of SiC MOSFET body diode was adjusted. By adjusting the conduction loss of the SiC MOSFET device, the fluctuation range of the junction temperature of the SiC MOSFET device was controlled, the smooth control of the junction temperature of the SiC device was realized, and the thermal stress of the device was reduced.

关键词： Logic gates   MOSFET   Silicon carbide   Junctions   Temperature measurement   Temperature   Immune system   Body diode   double-pulse test   high temperature   medium voltage (MV)   reverse recovery   silicon carbide (SiC) MOSFET  

摘要： This letter presents the impact of 6.5-kV silicon carbide (SiC) planar mosfet negative gate bias to their reverse-recovery behavior at room temperature to 175 degrees C. The difference between low- and medium-voltage (MV) SiC device third-quadrant characteristics under different gate bias is introduced. The impact of negative gate bias on conductivity modulation and reverse recovery is discussed. A custom clamped-inductive load switching test setup is developed to evaluate the MV SiC device's body diode performance. Results show that the reverse recovery worsens under negative gate bias at increasingly higher temperatures. The negative gate bias leads to an increase in reverse-recovery charge and energy.

关键词： FD-SOI   SCE   Heat-sink   Energy barrier   Hafnium oxide  

摘要： This paper aims to present a novel method to mitigate the undesirable issues associated with short-channel-effects (SCEs) and the critical lattice temperature of a fully depleted silicon-on-insulator (FD-SOI) MOSFET in the nanoscale regime. The proposed approach is based on simultaneously merging the energy barrier and heat-sink engineering simultaneously. Hafnium oxide as a high-k dielectric inside the channel region around the drain region is embedded to redistribute the band energy resulting in the enhancement of the energy barrier. This reformation of the band profile reduces variations in the channel depletion charge volume percentage caused by the drain voltage, thereby mitigating short-channel effects (SCEs). In order to promote effective thermal conduction, a portion of the buried oxide is replaced by doped P-type silicon which acts as an effective heat-sink. The devices under the investigation have been simulated using SILVACO software, considering the comprehensive physical models. Drain-Induced Barrier Lowering (DIBL), leakage current, I-on to I-off ratio, subthreshold swing, hot carrier effect and lattice temperature as the essential parameters have been successfully improved for the proposed device in comparison to the conventional device.

关键词： Current measurement   gallium nitride   half-bridge   Rogowski coil   silicon carbide   gallium nitride   half-bridge   Rogowski coil   silicon carbide  

摘要： This article quantitatively investigates the design considerations for a planar Rogowski coil. Within one printed circuit board (PCB), the Rogowski coil is placed between the overlapping dc-bus traces, the dc-link capacitor, and the half-bridge. This integration allows for measuring both dc-bus currents with one Rogowski coil, hence enabling the Silicon Carbide (SiC) mosfet switch transient current measurement of both half-bridge mosfets with one coil. A parametric mutual inductance equation and the Rogowski coil transfer function are proposed to simplify the design process of a planar Rogowski coil. Design considerations are evaluated. In additionally, the induced measurement error due to current crowding within the dc bus is investigated, and the impact of Rogowski coil windings exceeding the dc-bus trace width as a measure to reduce the mutual inductance error is explored and experimentally validated. A 106 mm(2) small planar Rogowski coil current sensor with a maximum bandwidth of 185 MHz is built. The prototype is evaluated for its parasitic parameters. Its current measurement performance is compared to that of a commercial Rogowski coil. Measurement results compare well between the planar Rogowski coil and the commercial Rogowski coil. In addition, measurements show that the mutual inductance of the proposed Rogowski coil is insusceptible to current crowding within the dc bus.

关键词： MOSFET   Silicon carbide   Inverters   Insulated gate bipolar transistors   Switches   Silicon   Control systems   Adaptive multipattern control strategy   full life cycle   hybrid switches (HySs)   safe operating range of the inverter   thermal reliability  

摘要： The Si/SiC hybrid switch (HyS) composed of Si IGBT and SiC MOSFET in parallel provides a low-cost and high-efficiency solution useful for inverters. The switching mode selection of HySs under various working intervals is important for ensuring good electrothermal performance of the inverter. In existing studies, switching strategies do not consider the effect of device fatigue aging, and the long-term operation reliability of the inverter may be severely limited. To avoid reliability degradation, an adaptive multipattern control strategy based on the aging state of HySs is proposed. The loss characteristics of HySs in a single-phase inverter is first analyzed. Considering the loss model and thermal impedance model, the influence of device fatigue aging on the maximum safe operating current of the inverter is investigated. A process for describing the safe operating range of the inverter considering the full life cycle is designed. Finally, based on the characterization results of the safe operating range, the mode-switching threshold current is dynamically adjusted for various aging levels of the HyS. The experimental results reveal that the Si/SiC-hybrid-switch-based single-phase inverter with an adaptive multipattern switching strategy can handle approximately 10% higher power capacity than the conventional fixed-threshold current switching strategy.

关键词： Analytical model   blanking time   dead time   silicon-carbide (SiC)  

摘要： This article presents an analytical derivation of the volt-second error caused by converter nonlinearities such as dead time and the finite switching speeds of the emerging medium voltage silicon-carbide MOSFETs. The analytical model considers the transient behavior of the MOSFETs, the gate-driving circuitry, and the intrinsic parasitic capacitances of the MOSFETs and the power module. The importance of compensating converter nonlinearities has been revived with the utilization of wide bandgap semiconductor devices as the increased switching frequency penalizes the relative impact of dead time squared in motor drive applications. The first-order analytical model is validated with experimental and simulated results of switching events of a 10 kV silicon-carbide MOSFET power module. In addition, the analytical model is utilized to map out the individual contributions from each time period of the switching event.

关键词： Mathematical models   Transient analysis   Integrated circuit modeling   Switches   Numerical models   Solid modeling   Semiconductor device modeling   Electromagnetic (EM) field   fully coupled model   switching transient   time domain  

摘要： For power electronics systems, the switching transient is critical for efficient and reliable energy conversion. While the electromagnetic (EM) field simulation is instrumental in analyzing switching transients, the simulation is complicated due to the voltage and current's complex distribution and their rapid changes. This article proposes a space partition and time domain decoupling method to model and simulate the 3-D fully coupled EM fields on the time domain for the switching transient, specifically simulating a SiC MOSFET turn-off transient. The space is partitioned into four modules based on different dominant feature in different materials, enhancing the model's numerical stability. Then the time domain decoupling strategy implements staged solving from independent modules to the fully coupled model, effectively coping with the challenges caused by complex coupling relations. We design the spatial fast-changing EM field measurement experiment to validate the model and method's accuracy. The proposed model reveals EM field dynamics during the transient and holds promise for facilitating practical power electronics design, such as the design of EM compatibility (EMC).

关键词： Temperature sensors   Temperature measurement   Monitoring   Logic gates   Junctions   Silicon carbide   MOSFET   Junction temperature monitor   miller plateau voltage   SiC MOSFET  

摘要： Online junction temperature monitoring of SiC MOSFET based on turn-off Miller plateau voltage (V-MP,V-off) has been explored in this article. As the junction temperature rises, V-MP,V-off experiences a decline while extending its duration, thereby enhancing the precision of sampling V-MP,V-off with a diminutive turn-off resistance (R-g,R-off). A novel extraction approach for V-MP,V-off is introduced, involving the continuous sampling of gate voltage via a network of resistances and an analog-to-digital converter (ADC). V-MP,V-off is ascertained through the discrepancy between two consecutive output points of the ADC. Validation of this monitoring technique is conducted through double pulse tests and a buck converter under varying temperatures. Empirical findings demonstrate a commendable linear relationship between V-MP,V-off and junction temperature. In the quest for a balance among thermal sensitivity accuracy, turn-off delay, and turn-off loss, a recommended value for R-g,R-off of SCT3040KR stands at approximately 15 ohm. Employing a 15 Omega R-g,R-off, the temperature sensitivity of V-MP,V-off for SCT3040KR and SCT3105KR hovers around -11.3 mV/degrees C and -9.1 mV/degrees C, respectively. With calibrations of aging and threshold voltages in advance, the proposed methodology exhibits promising potential in the realm of SiC MOSFET junction temperature monitoring.

关键词： Logic gates   Electric fields   MOSFET   Electron traps   Steady-state   Gate drive   metal-oxide-semiconductor field-effect transistor (MOSFET) devices   silicon carbide (SiC)   threshold voltage   silicon carbide (SiC)   threshold voltage  

摘要： The issue of dynamic threshold voltage drift in silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs) exacerbates their on-state resistance and conduction losses, thereby constraining their broader application. The dynamic threshold voltage drift in SiC MOSFETs occurs only under bipolar gate voltage stress, while it is not significant under unipolar gate voltage stress. Therefore, there exists the possibility of using a multilevel gate drive that divides the bipolar switching process of SiC MOSFETs into two stages of unipolar switching processes to suppress dynamic threshold voltage drift. Consequently, in this article, the effectiveness of multilevel gate drive is analyzed based on the previously reported local electric field enhancement model. In addition, a set of arbitrary level generator and a single-phase inverter experimental platform were designed for experimental validation. The findings reveal an inhibitory effect of multilevel gate drive on the dynamic threshold voltage drift of SiC MOSFETs. The research presented in this article holds reference significance for reducing the threshold voltage drift in SiC MOSFETs and improving device reliability and lifespan.

关键词： Logic gates   Wires   Stress   Silicon carbide   MOSFET   Voltage measurement   Thermomechanical processes   Failure detection   gate open-circuit failure   internal gate state   internal gate state   gate open-circuit failure   internal gate state   SiC MOSFETs   Logic gates   Wires   Stress   Silicon carbide   MOSFET   Voltage measurement   Thermomechanical processes  

摘要： Gate open-circuit failure caused by cracking and liftoff of gate bond wires has been demonstrated to be a new failure mode of silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors (mosfets), which can cause serious consequences such as shoot-through fault and gate-oxide breakdown. To enhance the reliability and robustness of SiC mosfets, a fast and accurate detection scheme for such failure is required. This article proposes a gate open-circuit failure detection method based on the extraction of the internal gate state. Although this state is unavailable externally, it can be extracted from gate current pulses. The gate open-circuit failures are then detected by checking the inconsistency between the drive signal and the internal gate state. Experimental results validate that the proposed method can accurately detect all types of gate open-circuit failures within 55 ns.