A method for a power system is disclosed. The method includes receiving signals, activating switches to pass a current from a power source to an apparatus. The method also includes deactivating switches and bypassing the power source. The power source may be a photovoltaic power source. The signals may be power line communication (PLC) signals.

A protection apparatus and method for an insulated gate bipolar transistor. The protection apparatus includes: a collection circuit, configured to collect a driving signal of an IGBT, perform delay processing in a case where the driving signal is a first level for switching on the IGBT or is a first level that is converted from a second level for switching off the IGBT and is used for switching on the IGBT, and output a first signal according to a signal after the delay processing and the driving signal; a detection circuit, configured to detect a voltage between a collector electrode and an emitter electrode of the IGBT, and output a second signal according to the voltage and a preset threshold value; and a determination circuit, configured to output an alarm signal or a protection signal in a case where both the first signal and the second signal are valid. Thereby, delay processing is performed with a simple structure without affecting driving signals, the performance of an IGBT is improved, the cost for circuit protection is reduced, and easy adjustment of the control on the IGBT is improved.

A photovoltaic array of photovoltaic solar cells; a smart dynamic programmable circuit breaker for electrically providing a pulsed 100 microseconds duration short circuit to the photovoltaic array electrical outputs, wherein a response time for the smart dynamic programmable circuit breaker is more than 1 millisecond when responding to a short circuit; a computer program comprising instructions that when executed by the processor perform functions that control the smart dynamic programmable circuit breaker, the computer program comprising: instructions to command the smart dynamic programmable circuit breaker to initiate the 100 microsecond pulsed short circuit; instructions to measure a current magnitude and current rise time of the smart photovoltaic system outputs during the 100 microsecond pulsed short circuit; and instructions to select a behavior curve from a plurality of smart dynamic programmable circuit breaker behavior curves 10% above the current magnitude and current rise time during the pulsed short circuit.

The invention relates to a transmitter for transmitting a process variable to a programmable logic controller. In a current mode a 4-20 milliamp current is fed into a burden and in a voltage mode 0-10 Volt signals are generated. The transmitter includes a process value input, a current stage, a voltage stage and a U/I output for the current or the voltage signal, and a U/I control input for switching between the two modes. The transmitter is configured to feed a current which is dependent on the voltage across the burden into the current stage via a resistor and thus to compensate for a current loss at the voltage stage which is dependent on the voltage across the burden.

A photovoltaic array of photovoltaic solar cells; a smart dynamic programmable circuit breaker for electrically providing a pulsed 100 microseconds duration short circuit to the photovoltaic array electrical outputs, wherein a response time for the smart dynamic programmable circuit breaker is more than 1 millisecond when responding to a short circuit; a computer program comprising instructions that when executed by the processor perform functions that control the smart dynamic programmable circuit breaker, the computer program comprising: instructions to command the smart dynamic programmable circuit breaker to initiate the 100 microsecond pulsed short circuit; instructions to measure a current magnitude and current rise time of the smart photovoltaic system outputs during the 100 microsecond pulsed short circuit; and instructions to select a behavior curve from a plurality of smart dynamic programmable circuit breaker behavior curves 10% above the current magnitude and current rise time during the pulsed short circuit.

An integrated circuit includes a signal pad, an output buffer having an output coupled to the signal pad and having an enable input, an input buffer having an input coupled to the signal pad and having an enable input, a counter, and a gating circuit. The counter is enabled to start counting down a predetermined count value when a voltage on the signal pad is both higher than a predetermined low threshold voltage and lower than a predetermined high threshold voltage, wherein the predetermined low threshold voltage corresponds to a threshold below which a voltage corresponds to a logic level zero and the predetermined high threshold voltage corresponds to a threshold above which a voltage corresponds to a logic level one. The gating circuit is configured to, in response to the counter expiring, disable the input buffer and the output buffer.

In order both to accommodate instantaneous current as well as overcurrent protection in accordance with the load, an overcurrent protection circuit has: a threshold value generation unit that, in accordance with a threshold value control signal, switches between setting an overcurrent detection threshold value to a first set value (∝ Iref) and a second set value (∝ Iset) lower than the first set value; an overcurrent detection unit that compares a sense signal in accordance with the current being monitored and the overcurrent detection value and generates an overcurrent protection signal; a reference value generation unit that generates a reference value (∝ Iset) in accordance with the seconds set value; a comparison unit that compares the sense signal and the reference value, and generates a comparison signal; and a threshold value control unit that monitors the comparison signal, and generates a threshold value control signal.

In a short circuit protection circuit, a first gate resistor is connected between a first output node of a gate driver and a first gate terminal. A first real-time control circuit operates to decrease a potential of the first gate terminal when the first real-time control circuit detects that a short circuit current passes through a first semiconductor switching element. The operation monitoring circuit includes a differential voltage circuit configured to output a potential difference between a potential proportional to a potential difference across the first gate resistor and the potential of a first power supply. The operation monitoring circuit monitors, based on an output of the differential voltage circuit, whether the first real-time control circuit is in operation.

A method for a power system having a string of a plurality of power sources connected across a power device includes connecting a plurality of safe voltage units having safety switches connected respectively across each of the power sources. The method includes sensing a plurality of parameters of the power sources, and monitoring for a signal transmitted from the power device. Each of the safety switches is activated to be OFF responsive to detecting the signal within a predetermined time period. Upon not detecting the signal from the power device within the predetermined time period, a safe mode of operation of the power system is entered in which the voltages of each of the power sources is reduced to a voltage level less than a predetermined voltage level by turning the safety switches ON.

A circuit breaker includes: at least one switching path of a first terminal of the circuit breaker to a second terminal of the circuit breaker; at least one semiconductor switch arranged in the switching path; a semiconductor version switch for predefinably interrupting the switching path upon actuation by a release of the circuit breaker; a characteristic variable unit connected to the release; and a current measuring arrangement for ascertaining a current profile through the at least one semiconductor switch, the current measuring arrangement being connected with the characteristic variable unit. The characteristic variable unit correlates a characteristic variable with a junction temperature of the at least one semiconductor switch that is ascertained from the current profile through the at least one semiconductor switch.