The failure detection device detects failure in switches that are selectively switched between conduction and non-conduction in a current path, and includes: two or more temperature sensors in which a resistance value between terminals changes in accordance with temperature changes, the two or more temperatures sensors being provided near two or more of the switches connected to each other in parallel, and the two or more temperatures sensors being electrically connected in series to each other; a detection unit that detects the combined resistance value of the two or more temperature sensors; and a determination unit that determines, based on a combined resistance value, that one or more of the two or more switches has failed.

The invention concerns a method for monitoring a cable strand containing multiple electrical lines, such that the cable strand is designed to conduct electrical energy generated by a generator in a wind turbine involving the steps: measuring the temperature of at least two of the electrical lines, comparing the temperatures of said lines, and determining whether the two temperatures deviate from one another by more than a predefined threshold.

The present disclosure relates to an apparatus for detecting malfunction of a relay, which includes a temperature determination unit configured to determine whether or not a relay resistor is overheated based on a resistance temperature of the relay resistor being connected to a relay; a charging voltage determination unit configured to determine whether or not a variation value of a charging voltage of a direct current (DC) link capacitor according to an operation start of an inverter system exceeds a reference variation value; and a relay malfunction determination unit configured to determine whether or not the relay is malfunctioned based on one or more the determination results whether or not the relay resistor is overheated and whether or not the variation value exceeds the reference variation value.

An electronic circuit arrangement for monitoring temperatures includes an electronic temperature-determining circuit with a temperature sensor for measuring an ambient temperature in the surroundings of the temperature sensor, configured to generate a comparator input signal depending on the temperature measured by the temperature sensor, an electronic reference circuit including a secondary temperature sensor for measuring an ambient temperature of the electronic circuit arrangement which is configured to generate a secondary comparator input signal that is dependent on the temperature measured by the secondary temperature sensor, an electronic comparator circuit which compares the primary and the secondary comparator input signal and generates a comparator output signal dependent on the two input signals. The temperature-determining circuit, the reference circuit and the comparator circuit are configured such that the comparator circuit generates a trigger signal as the comparator output signal if the temperature measured by the temperature sensor exceeds a temperature reference value.

A thermal protection circuit which relates to the field of electronic technologies can detect temperature of multiple locations simultaneously and adjust a preset threshold flexibly, thereby improving system reliability. The thermal protection circuit includes: at least one temperature sensor, a detection circuit, an execution circuit, a self-locking and triggering circuit, a protective temperature regulation circuit, and a power supply circuit. The at least one temperature sensor converts a temperature signal into an electrical signal and sends the electrical signal to the detection circuit; the detection circuit detects whether temperature reaches the preset threshold, and sends a turn-off signal to the execution circuit if the temperature reaches the preset threshold; the execution circuit cuts off power supply to the system; and the self-locking and triggering circuit maintains, a power-off state of the system until a power switch is triggered.

Systems and methods are provided for providing thermal protection to a power backplane printed circuit board. A distributed hotspot detection grid is included in the printed circuit board, the distributed hotspot detection grid comprising a plurality of passive temperature sensors spread across the printed circuit board to measure temperature increases. The plurality of passive temperature sensors are connected to a detection circuit for comparing signals from the passive temperature sensors to a reference signal. If the temperature increases on the PCB, electrical characteristics of at least one passive temperature sensor will change, resulting in a change of the input signal to the detection circuit. When the threshold is exceeded (indicating a potential short circuit or hotspot), the detection circuit outputs a shut down signal to the one or more power supplies connected to the of the backplane printed circuit board, to avoid catastrophic damage to the printed circuit board.

Circuits for providing overcurrent protection are disclosed herein. The circuits feature depletion mode MOSFETs connected to resistive elements, preferably, Positive Temperature Coefficient (PTC) devices, configured in such a way so that the voltage across the PTC device is the same as the gate-to-source voltage of the MOSFET. The circuit may further be configured using a TVS diode, for clamping the drain-to-source voltage of the MOSFET during the overcurrent events. Heat transfer between the MOSFET and the PTC device facilitates overcurrent protection. A two-terminal device including a depletion mode MOSFET, a PTC device, and a TVS diode may provide overcurrent protection to other circuits. A bidirectional circuit c including two MOSFETS disposed on either side of a PTC is also contemplated for AC voltage overcurrent protection.

A method for protecting an electrical grid against short circuits by controlling a temperature of terminal connections is disclosed, it can be used in industrial and consumer equipment to prevent fire hazardous situations. The technical result consists in the possibility of obtaining prompt and reliable information about a thermal state of terminal connections in an electrical circuit by avoiding an electrical connection between temperature sensors and a terminal connection. The metal device is used as a base for a temperature sensor. By using a triggering circuit, a voltage whose value depends on the temperature change is measured or compared or controlled with a predetermined voltage. If the temperature rises to a predetermined value or becomes higher than the predetermined value, the electrical circuit is opened or interrupted. After the temperature drops below the predetermined value, the electrical circuit is closed or restored.

An improved electric circuit structure for short circuit protection is applicable to examining a device under test, comprising a circuit breaking element, a thermistor, a filtering and rectifying module and a capacitor. A first end of the circuit breaking element is connected to a power source. The filtering and rectifying module is connected to a second end of the circuit breaking element, a ground, a first end of the thermistor and a first end of the capacitor. A second end of the capacitor is connected to a second end of the thermistor. The capacitor is connected in parallel with the device under test. The circuit breaking element disclosed in the present invention is a ceramic tube fuse and forms an open circuit when the device under test forms a short circuit. Meanwhile, the ceramic tube fuse withstands voltage between its first and second end without generating any physical damage.

Circuits for providing overcurrent protection are disclosed herein. The circuits feature depletion mode MOSFETs connected to resistive elements, preferably, Positive Temperature Coefficient (PTC) devices, configured in such a way so that the voltage across the PTC device is the same as the gate-to-source voltage of the MOSFET. The circuit may further be configured using a TVS diode, for clamping the drain-to-source voltage of the MOSFET during the overcurrent events. Heat transfer between the MOSFET and the PTC device facilitates overcurrent protection. A two-terminal device including a depletion mode MOSFET, a PTC device, and a TVS diode may provide overcurrent protection to other circuits. A bidirectional circuit c including two MOSFETS disposed on either side of a PTC is also contemplated for AC voltage overcurrent protection.