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Distributed energy resources (DERs) are becoming integral components of electric power distribution systems. In most cases, an isolated dc-dc converter forms part of the interface required to connect the DER output to the distribution system. Operation of the converter at high switching frequencies results in size reduction of passive components at the expense of increased switching losses. However, silicon carbide (SiC) power devices have the potential of operating at high switching frequencies without significant loss penalty because of their fast switching times and ability to work at high temperatures when compared to similar Si devices. SiC diodes have already displayed the ability to offer more ideal diode behavior than Si diodes. Engineering samples of SiC MOSFETs are depicting lower switching losses and conduction losses over Si MOSFETs. This display is making SiC devices attractive for dc-dc converters used to connect DERs to the distribution system. This paper particularly deals with the design of a 300-W 100-kHz dc-dc full-bridge converter using zero-voltage zero-current switching for comparison of SiC MOSFETs and diodes against Si MOSFETs and diodes. Index Terms--DC-DC converters, distributed energy resources (DERs), full bridge, silicon carbide (SIC) MOSFET, zero-current zero-voltage switching.

Silicon carbide (SIC) power devices are expected to have an impact on power converter efficiency, weight, volume, and reliability. Currently, only SiC Schottky diodes are commercially available at relatively low current ratings. Oak Ridge National Laboratory has collaborated with Cree and Semikron to build a Si insulated-gate bipolar transistor-SiC Schottky diode hybrid 55-kW inverter by replacing the Si p-n diodes in Semikron's automotive inverter with Cree's made-to-order higher current SiC Schottky diodes. This paper presents the developed models of these diodes for circuit simulators, shows inverter test results, and compares the results with those of a similar all-Si inverter. Index Terms--DC-AC conversion, hybrid electric vehicle, insulated-gate bipolar transistors (IGBTs), inverter, Schottky diode, silicon carbide (SIC).

This paper evaluates the capability of SiC power semiconductor devices, in particular JFET and Schottky barrier diodes (SBD) for application in high-temperature power electronics. SiC JFETs and SBDs were packaged in high temperature packages to measure the dc characteristics of these SiC devices at ambient temperatures ranging from 25 [degrees]C (room temperature) up to 450 [degrees]C. The results show that both devices can operate at 450 [degrees]C, which is impossible for conventional Si devices, at the expense of significant derating. The current capability of the SiC SBD does not change with temperature, but as expected the JFET current decreases with rising temperatures. A 100V, 25W dc-dc converter is used as an example of a high-temperature power-electronics circuit because of circuit simplicity. The converter is designed and built in accordance with the static characteristics of the SiC devices measured under extremely high ambient temperatures, and then tested up to an ambient temperature of 400 [degrees]C. The conduction loss of the SiC JFET increases slightly with increasing temperatures, as predicted from its dc characteristics, but its switching characteristics hardly change. Thus, SiC devices are well suited for operation in harsh temperature environments like aerospace and automotive applications. Index Terms--dc-dc converter circuit, device characterization, high temperature operation, packaging, silicon carbide (SIC) device.

A compact circuit simulator model is used to describe the performance of a 2-kV, 5-A 4-H silicon carbide (SiC) power DiMOSFET and to perform a detailed comparison with the performance of a widely used 400-V, 5-A Si power MOSFET. The model's channel current expressions are unique in that they include the channel regions at the corners of the square or hexagonal cells that turn on at lower gate voltages and the enhanced linear region transconductance due to diffusion in the nonuniformly doped channel. It is shown that the model accurately describes the static and dynamic performance of both the Si and SiC devices and that the diffusion-enhanced channel conductance is essential to describe the SiC DiMOSFET on-state characteristics. The detailed device comparisons reveal that both the on-state performance and switching performance at 25 [degrees]C are similar between the 400-V Si and 2-kV SiC MOSFETs, with the exception that the SiC device requires twice the gate drive voltage. The main difference between the devices is that the SiC has a five times higher voltage rating without an increase in the specific on-resistance. At higher temperatures (above 100 [degrees]C), the Si device has a severe reduction in conduction capability, whereas the SiC on-resistance is only minimally affected. Index Terms--DiMOSFET, silicon carbide (SIC).

Dynamic electrothermal circuit simulator models are developed for silicon carbide power diodes. The models accurately describe the temperature dependence of on-state characteristics and reverse-recovery switching waveforms. The models are verified for the temperature dependence of the on-state characteristics, and the di/dt, dv/dt, and temperature dependence of the reverse-recovery characteristics. The model results are presented for 1500 V SiC Merged PiN Schottky (MPS) diodes, 600 V Schottky diodes, and 5000 V SiC PiN diodes. The devices studied have current ratings from 0.25 A to 5 A and have different lifetimes resulting in different switching energy versus on-state voltage trade-offs. The devices are characterized using a previously reported test system specifically designed to emulate a wide range of application conditions by independently controlling the applied diode voltage, forward diode current, di/dt, and dv/dt at turn-off. A behavioral model of the test system is implemented to simulate and validate the models. The models are validated for a wide range of application conditions for which the diode could be used. Index Terms--Circuit simulation, diode model, merged PiN Schottky, PiN, power diode, reverse recovery, Schottky, SiC.

A new commercially available diode model is described. This unified model is capable of simulating the widest range of diode technologies of any presently available. The emphasis of this paper is on describing the model's extensive features and flexibility in the different domains of operation and is of particular interest in power applications. Index Terms - Diode, modeling, simulation.

A recently developed electrothermal network simulation methodology is used to analyze the behavior of a full-bridge, pulse-width-modulated (PWM), voltage-source inverter, which uses insulated gate bipolar transistors (IGBT's) as the switching devices. The electrothermal simulations are performed using the Saber circuit simulator and include control logic circuitry, IGBT gate drivers, the physics-based IGBT electrothermal model, and thermal network component models for the power-device silicon chips, packages, and heat sinks. It is shown that the thermal response of the silicon chip determines the IGBT temperature rise during the device switching cycle. The thermal response of the device TO247 package and silicon chip determines the device temperature rise during a single phase of the 60-Hz sinusoidal output. Also, the thermal response of the heat sink determines the device temperature rise during the system startup and after load-impedance changes. It is also shown that the full electrothermal analysis is required to accurately describe the power losses and circuit efficiency. Index Terms - Electrothermal, IGBT, inverter, modeling, pulse-width modulation, simulation.

The power MOSFET model performance required for accurate waveform simulation is evaluated for most converter circuits. Three models are thoroughly evaluated through CV plots, gate charge plots, and converter data. A procedure is given for evaluating any proprietary model using data book information with three simple simulations.

This paper presents a physics-based model of metal-oxide-semiconductor (MOS) controlled thyristor (MCT) using the lumped-charge modeling technique. As a relatively new power semiconductor device, little effort has been made thus far in creating an accurate model for simulation use. The only MCT model available to date is that using two bipolar transistors--a behavioral subcircuit model. This model works well for static operation, but has limitations in predicting the dynamic behavior of the device due to the omission of the internal device physics. The use of the lumped-charge modeling technique facilitates the inclusion of internal physical processes and the structural geometry of the device into the model. As a result, this technique provides a more realistic and accurate one-dimensional (1-D) model than any other presently available. This paper presents the successful implementation of the lumped-charge approach on hybrid bipolar-MOS power devices such as the MCT. Most importantly, this model is capable of predicting some dynamic soft-switching behavior of the device, which was never realizable by any SPICE-based simulators. The developed model is thoroughly verified through Saber simulation and experimentation. Index Terms--Hard- and soft-switching, lumped-charge models, MOS controlled thyristor-MCT, power device modeling, Saber simulation.