Industrial processes which use induction and dielectric heating are still relying on resonant converters based on vacuum tubes. New emerging medium-voltage silicon carbide (SiC) semiconductor power devices have a potential to replace vacuum tubes and allow for more efficient and compact converters in the high-frequency range. High-voltage packages have been proposed in the literature that are suitable for the 10 kV SiC metal-oxide-semiconductor field-effect transistors (MOSFETS), and its fast voltage switching capabilities in hard-switched applications have been demonstrated. However, no packaging is presented which allows the high-frequency operation of a 10 kV SiC MOSFET die. This study proposes the design of a power module for MHz resonant operation of a 10 kV SiC MOSFET. At high switching frequencies, the gate losses become substantial, thus the gate driver is included inside the power module package to ensure a low inductive and high thermally conductive design as seen from the gate driver. The inductance of the proposed power module layout structure is evaluated using ANSYS Q3D Extractor. The thermal performance of the integrated gate-driver circuitry is experimentally verified. Finally, the resonant operation of a medium-voltage SiC MOSFET power module is demonstrated experimentally at 1 MHz.

Results on structural, compositional, optical and electrical characterization of MOVPE grown AlGaN/GaN heterostructures with focus on understanding how the AlN buffer synthesis affects the top films are reported. The study demonstrates very good correlation between different methods providing a platform for reliable estimation of crystalline quality of the AlGaN/GaN structures and related to that electrical performance which is found to be significantly affected by threading dislocations (TD): higher TD density reduces the electron mobility while the charge carrier concentration is found to be largely unchanged. The attempt to vary the ammonia flow during the AlN synthesis is found not to affect the film composition and dislocation densities in the following heterostructures. An unusual phenomenon of considerable diffusion of Ga from the GaN film into the AlN buffer is found in all samples under the study. The obtained results are an important step in optimization of AlGaN/GaN growth towards the formation of good quality HEMT structures on sapphire and transfer of technology to Si substrates by providing clear understanding of the role of synthesis parameter on structure and composition of the films.

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High frequency industrial induction heating processes typically employ resonant inverters to reach high efficiency at high power levels. Advancements in wide band gap (WBG) device technology has made it feasible to push the possible frequency of these processes into the MHz regime using solid state technology. Several topologies can be applied, each with advantages and drawbacks. This paper presents a current source resonant inverter (CSRI) employing a custom designed power module utilizing 1700V SiC MOSFETs for MHz operation of a high‐Q resonant tank for induction heating, which presents new challenges in the inverter module design. An integrated gate driver structure is demonstrated driving four MOSFETs in parallel in MHz operation. Theoretical analysis predicts substantial parasitic influence on inverter operation, and thus an inverter is constructed to provide experimental verification of MHz operation, while the challenges associated with high frequency CSRI operation are discussed. In the experimental inverter setup, the fabricated power module achieves >90% efficiency for a calculated reactive power of 170 kVA and 2.3 kW output power during unloaded operation, validating the inverter design for extension to higher power loaded operation.

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