Abstract: In a VSC-converter for converting direct voltage to alternating voltage and conversely at least one phase leg (2) is arranged according to a NPC-connection. At least two of the four current valves (3-6) and the clamping rectifying members (10, 11) thereof are arranged close to each other and so that commutation currents generated on commutation of the converter therein will flow in substantially opposite directions.

Abstract: A Schottky diode of SiC has a substrate layer, a drift layer and emitter layer regions formed in the drift layer. A metal layer makes an ohmic contact to the emitter layer regions and Schottky contact to the drift layer. A depletion of the drift layer region between two adjacent emitter layer regions is allowed in the blocking state of the diode making the two adjacent p-type emitter layer regions form a continuous depleted region therebetween in this state.

Abstract: A semiconductor device of SiC is adapted to hold high voltages in the blocking state thereof. The device comprises two parts (1, 2) each comprising one or more semiconductor layers of SiC and connected in series between two opposite terminals of the device, namely a sub-semiconductor device (1) able to withstand only low voltages in the blocking state thereof and a voltage-limiting part (2) able to withstand high voltages in the blocking state of the device and adapted to protect said sub-semiconductor device by taking a major part of the voltage over the device in the blocking state thereof.

Abstract: A method and a device for controlling a switching operation consisting of a turn on or a turn off operation in a voltage controlled power transistor is provided. At least one current source is arranged at the control electrode of the power transistor. The at least one current source controls the recharging of at least one of the capacitances which occurs between the control electrode of the power transistor and the main electrode of the power transistor to determine the time rate of change of at least one of the voltage and current.

Abstract: In a method and apparatus used for detecting and handling a short circuit in a circuit having a plurality of power semiconductors connected in series the voltage is divided across the electrodes and each power semiconductor and the magnitude of a small proportion of the voltage is measured. The magnitude of the voltage is compared to a reference voltage at least from when the power semiconductor is turned on. The reference voltage is higher than the maximum voltage across the power semiconductor during normal operation. A short circuit is detected when the magnitude of the measured voltage exceeds the reference voltage.

Abstract: A semiconductor component, which comprises a pn junction, where both the p-conducting and the n-conducting layers of the pn junction constitute doped silicon carbide layers and where the edge of at least one of the conducting layers of the pn junction, exhibits a stepwise or uniformly decreasing total charge or effective surface charge density from the initial value at the defined working junction to a zero or almost zero total charge at the outermost edge of the junction following a radial direction from the central part of the junction towards the outermost edge.

Abstract: A semiconductor component comprises a pn junction in which both the p-conducting and the n-conducting layers of the pn junction are doped silicon carbide layers and the edge of at least one of the conducting layers of the pn junction exhibits a stepwise or uniformly decreasing total charge or effective surface charge density from the initial value at the defined working junction to a zero or almost zero total charge at the outermost edge of the junction following a radial direction from the central part of the junction towards its outermost edge.

Abstract: A semiconductor assembly with overvoltage protection is provided. The semiconductor assembly comprises at least two series connected power semiconductors, each of which is protected by at least one overvoltage protection device. The overvoltage protection device is activated at a predetermined voltage. The overvoltage protection device may be coupled in parallel across the emitter and collector of the power semiconductor or between the collector and gate of the power semiconductor. The overvoltage protection device includes a capacitor and a rectifier connected in series with the capacitor. The rectifier prevents the capacitor from discharging when the power semiconductor is in a conducting state. A voltage controller is connected to the capacitor and determines the voltage level to which the capacitor is discharged after an activation of the overvoltage protection device.

Abstract: A power supply apparatus for a drive unit in a high voltage converter circuit, the circuit has a plurality of power semiconductors connected in series. Each power semiconductor is connected to a drive unit for turning the power semiconductor on and off. The power supply apparatus consists of a capacitor and a regulator connected in parallel with the power semiconductor. The capacitor is connected to the drive unit and stores sufficient energy for power supply of the drive unit. The regulator regulates the voltage across the capacitor.

Abstract: A method and a device for control of a switching operation consisting of a turn-on or turn-off operation in a voltage-controlled power transistor (T1), wherein at least one current source (S1, S2) is arranged at the control electrode (G) of the power transistor for controlling the recharging of at least one of the capacitances which occurs between the control electrode (G) of the power transistor and the main electrodes (C, E) of the power transistor and thus to determine the time rate of change of at least one of the quantities voltage and current.

Abstract: In a method for producing a channel region layer in a SiC-layer for providing a voltage-controlled semiconductor device a layer of silicon being one of a) polycrystalline and b) amorphous is applied on top of the SiC-layer, an aperture is etched in the silicon layer extending to the SiC-layer, a surface layer of a certain thickness of the silicon layer is oxidized, and the lateral extension of the channel region layer is determined by removing the oxidized layer and carrying out a further implantation into the area exposed by the so formed enlarged aperture.

Abstract: A converter circuit has at least one switching device and a SiC diode arranged to be conducting when the device is turned off and reverse-biased when the device is turned on.

Abstract: The temperature-measuring transducer of a temperature-measuring system that includes a device for emitting energizing radiation, a temperature-measuring transducer which, upon excitation by the energizing radiation, will emit luminescent light, a detector for detecting the luminescent light emitted by the temperature-measuring transducer, and at least one optical fiber interconnecting the various elements is made of a crystalline sensor material which contains luminescent ions, at least some of these luminescent ions being so located in the crystal lattice of the sensor material that for each of said at least some luminescent ions each immediately adjacent anion substantially shows inversion symmetry in relation to that luminescent ion.