A circuit arrangement for switching an electrical load comprising an electrical switching element with a control input and an output; a control unit connected to the control input to drive the electrical switching element, in a first switching state, to generate a first output signal forming a switch-on signal for the load and, in a second switching state, to generate a second output signal, smaller than the first output signal, forming a switch-off signal for the electrical load; a safety output connected electrically to the electrical switching element output and to which the electrical load is connected; a decoupling apparatus arranged between the electrical switching element output and the safety output; a first output signal detecting apparatus connected to the electrical switching element output; and a second output signal detecting apparatus arranged in a circuit path between the decoupling apparatus and the safety output.

A method operates an electrical treatment device having a user-operable operating switch, and a motor electronics system with a motor control and an electric drive motor. The switch electrically connects to a drive voltage source and the motor electronics system. The motor electronics system electrically connects to the drive motor on an output side via the motor control. The method monitors whether an input voltage at the motor electronics system meets a closed criterion or an open criterion, wherein the closed criterion is characteristic of a closed switching state of the operating switch, and wherein the open criterion is characteristic of an open switching state of the operating switch, and when the open criterion is met, operates the motor control in a state from an open state set that includes a voltage control state for limiting an increase in the input voltage caused by the running-down electric drive motor.

A solid state switch (SSS) monitoring system of an electronic device includes a SSS sensing component that is electrically coupled to a solid state switch. The SSS sensing component generates a switch state signal to indicate a corresponding one of an actuated and an unactuated state of the solid state switch. A controller is communicatively coupled to the SSS sensing component. The controller restarts the SSS sensing component in response to determining that the SSS sensing component is in an inoperative state.

There is provided a semiconductor module capable of determining a semiconductor chip in which a short-circuit failure has occurred without being disassembled. A semiconductor module includes IGBT provided in each of semiconductor chips connected in parallel, switching of which being controlled by a gate voltage based on a gate signal; two external terminals input with the gate signal; a first connection route group having a first connection route and a third connection route connecting the external terminal and the IGBTs provided in the semiconductor chips respectively; and a second connection route group having a second connection route and a fourth connection route connecting the external terminal and the IGBTs provided in the semiconductor chips respectively.

Passive monitoring the integrity of current sensing devices and associated circuitry in GFCI and AFCI protective devices is provided. A protection circuit interrupter employs a capacitively coupled noise signal obtained by an arrangement of one or both of line side arms relative to a Rogowski coil. The noise signal is monitored while the line and load sides of a protective circuit interrupter are disconnected, and the connection of the line and load sides disabled if the noise signal fails to correlate sufficiently to a reference noise cycle. When the line and load sides are connected, the RMS value of the observed current signal is monitored such that the line and load sides are disconnected if the observed current signal fails to meet an RMS threshold. The observed current signal is compensated by subtracting the reference noise cycle prior to monitoring for the fault condition applicable to the protective device.

A fault detection method is used to determine whether a power switch coupled to a DC bus of a power conversion circuit is faulted. The method includes: detecting a bus voltage to provide a voltage signal and acquiring at least one detection value according to the voltage signal; providing control signals sequentially to turn off or turn on the power switch; determining that the power switch is a short-circuit fault if a first detection value is greater than or equal to a first threshold value when the power switch is turned off; determining that the power switch is an open-circuit fault if a second detection value is less than a second threshold value when the power switch is turned on; and providing an alarm signal or a disable signal when the power switch is the short-circuit fault or the open-circuit fault.

A front-end device for monitoring operation of an associated electric power device with semiconductor power switches generating a power output, e.g. a three-phase power output. The front-end device has input terminals arranged for connection to the electric phase(s) of the power output of the associated electric power device, and an electric circuit connected to the input terminals and connected to at set of output terminals. The electric circuit has a passive interconnection comprising electric semiconductor switches and diodes. The electric circuit serves to electrically block any high voltage component from the input terminals from reaching the output terminals, while allowing an on-state voltage of at least one semiconductor power switch in the associated electric power device to pass to the at least two output terminals. The front-end allows low voltage equipment to be connected to its output terminals for determining an on-state voltage of switches of the electric power device. Especially, embodiments with self-powered reference voltage circuits provided by zener diodes allow compact low cost versions for use in e.g. portable test equipment or as part of permanently installed health condition monitoring of power devices. The front-end device can be used as a simple and low cost solution for non-invasive health condition monitoring of power devices, e.g. power converters in such as power electric generation system or electric vehicles. Such monitoring allows predictive maintenance to be performed to avoid any faults in the power device that may cause permanent damages.

A switch identification circuit is provided. The switch identification circuit includes a detecting unit, a control unit, a connection unit, a first connection terminal, and a second connection terminal. The detecting unit is coupled with the first connection terminal and the second connection terminal, and configured to detect voltages at the two connection terminals to output a detection signal. The connection unit is electrically coupled with a power-supply device configured to provide a driving voltage to the two connection terminals. The control unit is coupled with the detecting unit and the connection unit, and configured to determine whether the first connection terminal and the second connection terminal are short-circuited according to the detection signal. If the two connection terminals are short-circuited, the control unit is configured to output a connection-enabling signal to the connection unit, to make the connection unit control the power-supply device to stop supplying the driving voltage.

An embodiment relates to a switchgear for a single-phase motor and a three-phase motor, the switchgear including a processing unit and a first, second and third current path, the first and third current path each including a current transformer. The processing unit is adapted to detect the current I.sub.1 of the first current path and the current I.sub.3 of the third current path. To provide a cost-effective switchgear for a one-phase motor and a three-phase motor which is adapted to identify the failure of every single phase in the three-phase operation and a phase failure in the one-phase operation, the processing unit is designed such as to detect the currents I.sub.1, I.sub.3 of the first and third current path and to determine, based on the phase shift between the detected currents I.sub.1, I.sub.3 of the first and third current path in which operating mode the switchgear is operated.

A diagnostic system for a DC-DC voltage converter is provided. The diagnostic system includes a first temperature sensor generating a first output voltage indicating a temperature level of a high voltage bi-directional MOSFET switch. The diagnostic system includes a microcontroller that samples the first output voltage at a first sampling rate utilizing a first channel in a first bank of channels to obtain a first predetermined number of voltage samples. The microcontroller determines a first number of voltage samples in the first predetermined number of voltage samples in which the first output voltage is greater than a first threshold voltage. The microcontroller sets a first temperature diagnostic flag equal to a first fault value if the first number of voltage samples is greater than a first threshold number of voltage samples indicating the high voltage bi-directional MOSFET switch has an over-temperature condition.