In this work, the authors present their investigations of the benefits of combining the latest silicon carbide MOSFETs with novel packages for electronic ballasts of inductively coupled plasmas. Such plasmas require MHz inverters with output powers above 2 kW. Additionally, for a breakthrough of the technology efficiencies >90% have to be realised. It has been shown that a combination is achievable with SiC FETs. Nevertheless, even though the transistors have undergone significant development in recent years, one limiting factor has mostly remained untouched. The common TO‐247 package does not fit to the requirements of a fast switching application. Within the latest launch of the new generations of SiC MOSFETs, some are available in novel packages with kelvin source connection, like 4pin TO‐247 and 7pin D2Pak. The authors compare three versions of the latest generation in a resonant full‐bridge inverter and in application‐oriented test. Thereby, the 7pin D2Pak and one of the 4pin TO‐247 transistors were 65 mΩ devices and the second 4pin TO‐247 FET was a 45 mΩ device. For the investigations, the authors made simulations, built three MHz inverters, and conducted measurements. Consequently, efficiencies of 93.9% could be achieved at a switching frequency of 2.5 MHz and an output power of P _out =2.6 kW.

Wide band-gap resonant converters operating with zero voltage switching (ZVS) recently proved the conversion of up to $25 \,\mathrm{k}\mathrm{W}$ at $3 \,\mathrm{M}\mathrm{Hz}$ with an efficiency of $\approx$$94 \%$. This is of special interest for any application where power in middle frequency range is required since typically achieved efficiencies for those frequencies are in the range of $60\% \hbox{--}70\%$. Inductively coupled plasma (ICP) based applications would significantly benefit from this fact, but they entail special driving challenges. ICP loads exhibit strong impedance variations during ignition and operation, which means a high limitation factor when driving them with resonant converters. This article offers a deeper look into this topic through the example of a $10 \,\mathrm{Pa}$ Xenon lamp. The ignition transient is measured and analyzed while driving the system with a Silicon Carbide (SiC)-based resonant converter. An FEM simulation modeling the electromagnetic, thermal, mechanical, and plasma properties is also performed. The results are contrasted with the corresponding measurements showing as well the simulation usefulness as a design tool. Theoretical calculations of the intrinsic limits for ZVS resonant power conversion are also offered. This provides an insight into which analysis and control methods would make ICP loads compatible with these converters and, therefore, able to benefit completely from their efficiency and power density benefits.

In this work we present results of investigations on the usability of ISOPLUS SMPD SiC-MOSFET phase-leg modules for medium-frequency resonant inverters. These modules combine excellent thermal performance, very low parasitic inductances and good switching performance with the benefits of surface-mountable packages. In the first step, a SPICE and a thermal simulation of a half-bridge inverter using the SMPD module and one using discrete SiC-MOSFETs in TO-247 package was performed. Here, the semiconductor losses of the discrete devices were 2.5 times higher than the one of the SMPD module. In the second step, a modular prototype of a resonant MHz half-bridge inverter with the SMPD module was built. A short circuit test and efficiency measurements with an ohmic load showed an excellent switching performance of the SMPD SiC-MOSFET phase-leg module in the MHZ range. With the inverter prototype, an efficiency of > 95% was measured, at a switching frequency of 2.01 MHz and an output power of 5.6 kW delivered to the load resistor.

In this paper, an efficient inductively coupled medium pressure source for ultraviolet radiation (UV-source) is demonstrated. The lamp was operated with powers up to 3 kW while the radiation and the coldest point temperature were measured. In addition, different coil geometries were investigated. Here a symmetrical and asymmetrical winding density were compared. Also the operation pressures and DC to radiation efficiencies are presented. In this work, an operation pressure of one atmosphere and an UV-efficiency (200–380 nm) of 15.5% was achieved. This is comparable to conventional medium pressure Hg-lamp technology. The main advantage of the presented inductive lamp is the electrodeless operation and therefore the longer service life, since an electrode failure is eliminated.

This paper introduces a control algorithm for soft-switching series LC converters. The conventional voltage-to-voltage controller is split into a master and a slave controller. The master controller implements constant current, constant voltage (CCCV) control, required for demanding applications, for example, lithium battery charging or laboratory power supplies. It defines the set-current for the open-loop current slave controller, which generates the pulse width modulation (PWM) parameters. The power supply achieves fast large-signal responses, e.g., from 5 $\mathrm{V}$ to 24 $\mathrm{V}$ , where 95% of the target value is reached in less than 400 $\mathrm{s}$ . The design is evaluated extensively in simulation and on a prototype. A match between simulation and measurement is achieved.

Inductive plasma discharge has been a part of continuous investigations since it was discovered. Especially the E- to H-mode transition and the hysteresis behavior have been topics of research in the last few decades. In this paper, we demonstrate a way to reduce the hysteresis behavior by the usage of a microwave ignition system. With this system, a significant decrease of the needed coil current for the ignition of the inductive driven plasma is realized. For the microwave generation, a magnetron as in a conventional microwave oven is used, which offers a relatively inexpensive way for microwave ignition aid. At the measured pressure of 7.5 Pa, it was possible to reduce the needed coil current for the inductive mode transition by a factor of 3.75 compared to the mode transition current without the ignition aid. This was achieved by initiating the transition by a few seconds of microwave coupling. The performed simulations suggested that the factor can be further increased at higher pressures. That is especially interesting for plasmas that are hard to ignite or for RF-sources that cannot deliver high enough currents or frequencies for the ignition.