The present invention concerns a method and a system for increasing the lifetime of at least two power dies or power modules. The invention: senses the temperature of the power dies or the power modules, identifies, for each power die or power module, temperature cycles from the sensed temperatures, determines, for each power die or power module, reliability parameters from the identified temperature cycles, determines, for each power die or power module, reference temperatures, subtracts, for each power die or power module, the sensed temperature of the power die or power module from the determined reference temperature of N the power die or power module, adjusts the duration of the conducting time and/or the switching delay of at least one power die or power module according to the sign of the output of the subtraction.

A method of detecting a failure of an antiparallel thyristor, wherein the antiparallel thyristor includes a first thyristor and a second thyristor connected in parallel and in opposite directions, and is configured to control power supplied from an alternating current power supply to a load, the method including: detecting, as a first detection value, a voltage or a current supplied to the load when ceasing an output command for the second thyristor and issuing an output command for the first thyristor; detecting, as a second detection value, the voltage or the current supplied to the load when ceasing the output command for the first thyristor and issuing the output command for the second thyristor; and determining the failure of the antiparallel thyristor based on a difference between the first detection value and the second detection value.

A welding system includes a power supply coupled to a power source and configured to receive a power signal. The power supply includes power conversion circuitry having one or more silicon-controlled rectifiers (SCRs) and configured to rectify the power signal to generate a DC signal for use in providing welding power. The welding system also includes an SCR detection system configured to receive a signal indicative of an inductor current of the DC signal and a signal indicative of a voltage of the DC signal. The SCR detection system is further configured detect a non-firing, open, or shorted SCR in the one or more SCRs based on the inductor current and the welding voltage of the DC signal.

A system for measuring soft starter current includes a current monitoring system having a controller and a current transfer device that includes a first solid state switching device. A first current sensor is coupled to the first solid state switching device and the controller to sense off-state current of the first solid state switching device. The controller is configured to determine an operational status of the first solid state switching device.

A probe device includes a measurement stage and an output connection. The measurement stage has a circuit configured to be connected with a power device under measurement, to measure one or more of a voltage or a current of the power device under measurement. The measurement stage is configured for at least one of a power supply rail or a reference of the measurement stage to be coupled to an electrode of the power device when the one or more of the voltage or the current is measured. The output connection is configured to communicate one or more of the voltage or the current of the power device under measurement that is measured or a derived parameter to a digital processing device or an external computer acquisition system.

A method analyzes an operation of a power semiconductor device. The method includes: providing a set of reference voltages of the device and a set of corresponding reference currents; measuring, within a predetermined time-interval, Nframe on-state voltages and Nframe corresponding on-state currents of the device to obtain Nframe measurement points, Nframe being an integer number equal to or greater than 2; adapting the set of reference voltages by carrying out a least squares fit to the Nframe measurement points; and using the adapted set of reference voltages to analyze the operation of the power semiconductor device.

Provided is an electric circuit that may be part of a power converter and which includes a plurality of electrically connected thyristors. Each thyristor has a gate terminal electrically connected to a gate drive unit adapted to generate gate pulses for triggering the thyristor. At least one of the plurality of gate drive units is adapted to measure the gate voltage of the respective thyristor after one or more gate pulses have been applied to the respective thyristor. The measured gate voltage may be used to determine if a thyristor has not been triggered by the gate pulse(s) e.g., if the gate voltage is below a voltage threshold.