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Peak current ratings for diodes is usually given as a surge current rating for a specified pulse (either a 60 Hz half cycle sine wave or a 10 ms pulse). These surge current ratings can be as high as several 10's of kA for the larger devices. We have tested and found that these devices are capable of conducting much higher peak currents for short pulse durations (100's of microns's). These short pulse, peak current ratings are important for the design of power supplies that deliver high currents for short durations (as in distributed energy stores). This paper describes theoretical and experimental results obtained for diodes operated at high peak currents for short pulse durations. We explain what the peak current rating depends on for short pulses. We also describe a model to determine what the peak current rating should be for short pulses. We then describe our experimental setup and the test procedures used for obtaining V-I data. Results are given for a 100 microns long pulse at peak currents up to 200 kA for a single device.

Digital simulations were conducted to analyze the thyristor valve turn-on phenomenon while a valve arrester is conducting which gives the most severe turn-on stress for the valve. The effects of various other parameters were clarified, too. Based on this analysis, two test methods were proposed that verify a valve turn-on during arrester conduction, and their effectiveness was described. Then the non-repetitive turn-on test given in the IEC Standard Pb. 700 and IEEE Standard 857 was studied and a new test voltage level on the basis of these analyses was proposed.

Silicon carbide (SIC) process technology has made rapid progress, resulting in the realization of very promising electronic devices and sensors, enabling advanced solutions in power industry, and mobile systems. In particular, for electronics working under harsh environmental conditions, SiC devices reach unprecedented performance. Transfer to production has already started for some applications. Index Terms-High-temperature electronics, power devices, SiC devices, SiC technology, silicon carbide.

Insulated gate devices, such as metal oxide semiconductor field effect transistors (MOSFETs) or insulated gate bipolar transistors (IGBTs), are increasingly used in high-voltage power converters where a request for fast power switches is growing. Series connection of devices is a viable approach to manage voltages higher than the blocking voltage of the single device. The main problem in such an application is to guarantee the voltage balance across the devices both in steady-state and during the switching transients. In this paper a novel approach is presented, which is used to equalize the voltage sharing during the switching transients. The main advantages of the proposed method consist in avoiding the traditional use of the snubber capacitors, in the output power side, and in working on the gate side. The application of the proposed gate drive technique is firstly discussed and compared with different solutions, hence, validated by experimental tests applied to the control of series connected devices. Finally, a comparison is performed between the transient behaviors of two different configurations: a single switch with high-voltage blocking capability, and in alternative a series of two devices which together ensure the voltage blocking capability of the single switch. The better performances of the latter configuration, working with the proposed control circuit, over the former have been experimentally demonstrated. Index Terms--Active clamp, driving circuit, insulated gate bipolar transistor, MOSFET, series connection.