Abstract: The document specifies a method for fault handling in a converter circuit for switching three voltage levels, in which the converter circuit has a converter subsystem provided for each phase (R,S,T), in which a top fault current path (A) or a bottom fault current path (B) in the converter subsystem is detected, the top fault current path (A) running through the first, second, third and sixth power semiconductor switches in the converter subsystem or through the first and fifth power semiconductor switches (S1, S5) in the converter subsystem, and the bottom fault current path (B) running through the second, third, fourth and fifth power semiconductor switches in the converter subsystem or through the fourth and sixth power semiconductor switches in the converter subsystem, and in which the power semiconductor switches are switched on the basis of a fault switching sequence.

Abstract: A breakdown precautionary system of a semiconductor equipment includes a semiconductor equipment with a coil heater, at least a voltage/current detector, and an alarm system. The voltage/current detector detects the voltage and current of the coil heater at the same time. An alarm system will send an alarm signal and initiate an interlock safety measure of the semiconductor equipment when the detected current of the coil heater is 0 ampere.

Abstract: A multi-level power converter is disclosed. The converter includes a DC power source having N (N is an Integer more than two)-level voltage potentials, and a plurality of switching legs connected in parallel to the DC power source. The switching leg has switching elements in series connection, and clamp diodes connected between intermediate DC potential terminals to middle points of the switching legs. The converter is provided with a control means for supplying gate pulses to the switching elements, and a supervising means for supervising every switching element to output a failure signal. The converter further includes a logic operating means for detecting an over-current failure of main circuit elements to output a device fault signal using the failure signals An operation of the logic operating means at least includes AND condition of at least two failure signals to output the device fault signal.

Abstract: A current inductive timer socket comprises: a principle relay circuit 1, a reed relay circuit, a plurality of diodes, a reed relay and a resistance, a counter circuit, a holding circuit, a time switch circuit and amplification circuit. When the electric appliance is in use, a signal of voltage drop produced at both ends of the rated resistance will be amplified by the operational amplifier and then transmitted to the counter circuit and an overload detecting circuit, making the counter circuit start to count automatically, and thus time operation is carried out. further, when electric appliance is overloaded or in the case of short circuit, the power source can also be cut off automatically.

Abstract: A load drive control circuit for controlling a load that includes connection terminals. The load drive control circuit includes bridge circuits respectively connected to the connection terminals of the load. Each bridge circuit includes two semiconductor elements, which are connected between a power supply and ground, and an output terminal. The semiconductor elements are each controlled to be switched between activated and deactivated states. The output terminal of each bridge circuit generates a bridge output that varies in accordance with a combination of the activated and deactivated states of the semiconductor elements in the bridge circuit. A detection circuit detects whether a short circuit is occurring in the connection terminals. A control circuit switches the bridge circuits to electrically disconnect the load from the power supply when a short circuit is occurring during a period in which the load is in a suspended state.

Abstract: The present invention is to provide a voltage detecting apparatus, which can downsize a circuit, reduce costs and detect a voltage with high accuracy, the voltage detecting apparatus to detect a voltage by using a flying capacitor. Furthermore, the voltage detecting apparatus does not halt whole functions. The first zener diode is connected to the first resistor R1, which divides a voltage stored with the capacitor as a flying capacitor into a detectable voltage at a microcomputer, in parallel. Furthermore, the voltage detecting apparatus prevents more than a zener voltage of the first zener diode from applying to the input of the microcomputer.

Abstract: A system and method for accomplishing power swing blocking and unstable power swing tripping schemes during disturbances of electrical networks is disclosed. The disclosed system and method eliminates the requirement of stability studies. The no-setting scheme utilizes the swing center voltage of the electrical network to carry out its functions.

Abstract: An overcurrent detecting device for detecting an overcurrent in a load circuit for controlling ON/OFF of a load by using a semiconductor switch, includes a driver circuit that outputs a driving signal to the semiconductor switch, a reference voltage generating circuit that generates a reference voltage, a measured voltage generating circuit that generates a measured voltage corresponding to a voltage generated across the semiconductor switch, a first comparator that compares the measured voltage with the reference voltage and outputs an overcurrent determination signal when the measured voltage is greater than the reference voltage, a saturation determining circuit that determines that a differential voltage between a control voltage of the semiconductor switch and a voltage to be applied to a positive side of the semiconductor switch is greater than a predetermined voltage, and an overcurrent signal switching circuit that performs a switching operation so as to enable the overcurrent determination signal to

Abstract: Device miniaturization is made possible by building a battery protection circuit in a microcomputer. A secondary battery protection device includes a voltage detection device that detects a voltage of a power supply circuit including a secondary battery, a current detection device that detects a current of the power supply circuit, and a battery protection circuit that shuts off the power supply circuit based on a signal representing a detection made by the voltage detection device or the current detection device of an excess current that is generated in the power supply circuit. The protection circuit is built in a microcomputer.

Abstract: A pulse width modulation (PWM) circuit includes a turn on/off switch and a PWM controller. The first terminal of the turn on/off switch is coupled to a turn off voltage. The control terminal of the turn on/off switch receives a turn on/off signal to decide whether the circuit between the first terminal and the second terminal of the turn on/off switch is turned on or not. The PWM controller includes a PWM pin and a turn on/off device. The PWM pin is coupled to the second terminal of the turn on/off switch to output a PWM signal. The turn on/off device is coupled to the PWM pin to decide the turn on/off of the PWM controller according to a signal swing state of the PWM pin.

Abstract: In circuit abnormality determining apparatus and method applicable to a brake control apparatus, an abnormality determining section determines at least one of an abnormality location of the electric circuit and an abnormality kind of the electric circuit on a basis of monitoring results of a current state in the electric circuit detected by a current detection section, a voltage state of the electric circuit detected by a open circuit detection section, and a power supply voltage.

Abstract: An apparatus can include a fault condition detector configured to detect a fault condition in an electrical system, a delta d-q power value generator configured to generate a delta d-q power value temporally corresponding to the detected fault condition, and a characterizer circuit configured to characterize the fault condition relative to the apparatus responsive to the delta d-q power value. Methods can include detecting a fault condition in an electrical system and determining changes in d-q component voltage and current temporally corresponding to the detected fault condition. Such methods can further include characterizing the fault condition responsive to the determined first and second changes and controlling an apparatus based on characterizing the fault condition.

Abstract: A power semiconductor device is provided with an output transistor, a load control circuit, and a pull-up circuit. The output transistor is connected between a power supply terminal provided to receive a power supply voltage and an output terminal to be connected with a load. The load control circuit is adapted to feed the gate voltage to the gate of the output transistor. When short-circuiting of the load occurs, the load control circuit stops feeding the gate voltage to the output transistor. The pull-up circuit is connected between the power supply terminal and the gate of the output transistor. The pull-up circuit is adapted to discharge electric charges on said gate of said output transistor, when short-circuiting of the load occurs with the voltage level on the power supply terminal lowered than the power supply voltage.

Abstract: Low cost apparatus and methods of detecting arc faults for better discriminating electrical events. The arc fault detection apparatus includes a current sensor, a di/dt input sense circuit, a dv/dt input sense circuit, and a processing unit. The current sensor monitors a power line current, and provides high frequency components of the power line current to the di/dt input sense circuit. The dv/dt input sense circuit monitors a power line voltage. The di/dt and dv/dt input sense circuits generate signals carrying information relating to changes in the power line current and the power line voltage, respectively. The processing unit analyzes these changes in the power line current and the power line voltage to discriminate detected electrical arcing events from nuisance loads with increased accuracy.

Abstract: A stray voltage detection and isolation system. The stray voltage detection portion of the system includes a water delivery system electrically isolated from an electrical transmission system of an electric utility. Meters measure an electrical characteristic between a first test-point that is electrically connected to the water delivery system and a plurality of second test-points. The second test-points are at earth grounds at locations electrically connected to the first test-point. The location of a source of stray voltage can be determined by evaluating differences in the measured electrical characteristics. The stray voltage isolation portion of the system electrically isolates a water delivery system. A controller maintains an air gap between a water source and a first storage tank or between the first storage tank and a second storage tank. The second storage tank provides the electrically isolated water.

Abstract: Device miniaturization is made possible by building a battery protection circuit in a microcomputer. A secondary battery protection device includes a voltage detection device that detects a voltage of a power supply circuit including a secondary battery, a current detection device that detects a current of the power supply circuit, and a battery protection circuit that shuts off the power supply circuit based on a signal representing a detection made by the voltage detection device or the current detection device of an excess current that is generated in the power supply circuit. The protection circuit is built in a microcomputer.

Abstract: This invention relates to a power supply circuit protecting method and a power supply circuit protecting apparatus. The apparatus is provided with a power supply circuit for converting a voltage from a three-phase alternating current inputting power supply into a predetermined voltage, and an output operation circuit for performing a predetermined operation by adopting an output voltage from the power supply circuit as input. In the apparatus, based on a current value on the input side or the output side of the power supply circuit, abnormality of the supply voltage is judged, and when there is an abnormality, the output operation circuit is controlled.

Abstract: A test device is provided for testing stability of a computer when the computer is started up or shut down. The test device includes a monolithic chip and a switch module. The monolithic chip includes an input port and an output port. The input port receives a high level or a low level signal from the computer. A test control module is disposed in the monolithic chip. The switch module includes an input pin coupled to the output port of the monolithic chip and a pair of output pins corresponding to the input pin. The pair of output pins is connected to the computer, for controlling the computer to be started up or shut down. The input port of the monolithic chip is connected to the computer for detecting a state of the computer.

Abstract: A power converter includes a steady-state controller for outputting a first voltage command such that a detected power value matches a power command, a transient controller for outputting a second voltage command such that a voltage detected before the occurrence of a fault is maintained when the fault occurs, and a voltage command selector for switching the voltage command in such a way that the first voltage command is output when no power fault is detected and the sum of the first and second voltage commands is output when any power fault is detected.

Abstract: The application of electric power from a power source to a load is controlled by detecting the magnitude of electric current flowing to the load and producing a first signal level that is indicative of that magnitude. The first signal level is compared to a reference signal level which comparison produces an output signal. Either the first signal level or the reference signal level is altered in response to variation of voltage applied to the load. This results in the output signal indicating when electric power consumed by the load exceeds a threshold level. The flow of electric current from the power source to the load then is controlled in response to the output signal.

Abstract: A metering device of a power substation and method are provided for operating on a secondary analog waveform output by a transformer assembly receiving a primary waveform. The method includes stepping down the secondary waveform and generating a corresponding output signal; operating on the corresponding output signal for generating a corresponding first digital signal having a value proportional to the corresponding output signal and within a first range; and operating on the corresponding output signal for generating a corresponding second digital signal having a value proportional to the corresponding output signal and within a second range. The method further includes processing the first digital signal and outputting a corresponding first output signal; processing the second digital signal and outputting a corresponding second output signal; processing the first and second output signals; and generating output corresponding to the processing of the first and second output signals.

Abstract: A switching regulator type power supply apparatus that converts an input voltage and then feeds the voltage thus converted to a smoothing circuit, and that operates in such a way that an output from the smoothing circuit becomes equal to a predetermined output voltage includes a control circuit for generating a control signal by a PWM scheme so that the output becomes equal to the predetermined output voltage, and a switching element that is switched by the control signal so as to convert the input voltage and feed the voltage thus converted to the smoothing circuit. Here, based on an external signal for turning on/off an output of the output voltage, a supply path for supplying an operating power to elements constituting the control circuit is switched between a conducting state and a non-conducting state.

Abstract: A time-synchronized trip implementation for a motor circuit protector (MCP) having a reconfigurable microcontroller. The microcontroller causes a power supply to, be charged for an initial time period during a charging mode. An onboard comparator is configured for a predetermined self-protection level of the MCP, and fault currents that exceed the comparator's threshold will directly drive a solenoid to trip the MCP. The microcontroller reconfigures the comparator's threshold to both measure and charge the power supply toward a stored energy trip voltage, which will charge quickly when high fault currents are present. As a result, self-protection is not compromised. After the trip voltage is reached, the microcontroller reconfigures the onboard comparator's threshold for self-protection trip levels. When a trip event occurs in this mode, stored energy trip activation occurs.

Abstract: A status indicator indicates an operating state, including an electrical malfunction, of an electrical load that is located and controlled from locations remote from a monitoring location.

Abstract: An electrical control apparatus comprises a current sensor and a current inhibiting circuit that inhibits current flow between first and second terminals of a bicycle dynamo when current sensed by the current sensor is below a selected value.

Abstract: There is provided a method of testing an electrical switchgear system. A node in the electrical switchgear system monitors a power line signal and controls a breaker based on the power line signal. The method includes applying an analog signal to the node, and receiving data representing a status of the breaker. The analog signal simulates the power line signal.

Abstract: A reliable uninterruptible DC power supply device. The DC backup power supply device includes an AC/DC converter, a DC/DC converter, voltage step-up/down choppers and a battery connected to a DC path of a main circuit connected with a load via a switch, and a microcomputer. In the device, under control of the microcomputer, the voltage step-up/down choppers are first operated under a condition that the MOS FET was turned OFF for self diagnosis of the backup power supply device. Next, the switch is turned ON to execute the remaining self diagnosis. The DC backup power supply device can execute its self diagnosis with a reduced likelihood of danger of exerting an adverse effect on the main circuit and also can exhibit a reliable uninterruptible power supply function.

Abstract: A switch in an inductive circuit is prevented from avalanche operation when the switch is turned off. By preventing avalanche, the associated EMI is reduced or eliminated. Switch avalanche can be prevented using an active component, such as a transistor, or a passive component, such as a resistor, coupled to the switch gate to control current in the switch gate. By controlling current in the switch gate during turn-off, avalanche operation can be prevented without a significant increase in turn-off energy.

Abstract: Apparatus for detecting failure of an isolation device includes a current sensor to sense current through the isolation device and a circuit responsive to the current sensor output signal and to an enable signal that controls the isolation device for providing an Early Failure Warning (EFW) signal indicative of whether the isolation device has failed. The enable signal is at a first logic level when the isolation device is on and is brought to a second logic level to disable and test the isolation device. Also described is a method of detecting a failure of an isolation device including disabling the isolation device, sensing a current through the isolation device, and providing an EFW signal indicating that the isolation device has failed if the current through the isolation device is greater than a predetermined level when the isolation device is disabled.

Abstract: An unbalanced current detection circuit determines when a multi-phase, normally-balanced load is unbalanced. The detection circuit of the present invention includes a plurality of current-squaring circuits, each squaring a sensed current of one of the phases. A summing circuit produces a sum of the squares of the currents. If the load is balanced, this sum should be relatively constant, perhaps changing only slowly over time, with little or no ripple from that relatively constant value. In an unbalanced current condition, the sum of the current squares would consist of an average (dc) component plus a ripple (ac) component. If the amplitude of the ripple current exceeds a threshold, it is determined that the currents are unbalanced.

Abstract: There is provided an electronic apparatus including a first interface to which a first device is connectable, a second interface to which a second device is connectable, and a power supply control circuit that controls a current to be supplied to the first and second interfaces. With the above arrangement, the power supply can efficiently be controlled for a plurality of interfaces without increasing the number of power supply control circuits.

Abstract: A power source monitor and method to monitor various operating line conditions of an electrical power outlet comprising measuring line voltage and frequency, analyzing wiring conditions, displaying the line conditions and generating an alarm when any of the line conditions are not within a corresponding predetermined range.

Abstract: A method and circuit for providing a regulated current to a load stabilized with respect to the load current, a load voltage, and a circuit temperature. The circuit includes a power pass device, a current sense device, a voltage sense amplifier, a reference device, a temperature sense device, and a current control device. In one embodiment, the current control device receives a first signal based on the sensed load current, a second signal based on the sensed load voltage, a third signal based on the circuit temperature, and a reference signal. A lesser of the second, third, and reference signals is selected and differentially combined with the first signal. A control signal is derived from the combination to control a regulation of the load current. In a further embodiment, an external signal may be provided to the current control device for stabilization with respect to an external parameter.

Abstract: Subscriber line interface circuitry includes an integrated circuit having sense inputs for a sensed tip signal and a sensed ring signal of a subscriber loop. The integrated circuit generates a subscriber loop linefeed driver control signal in response to the sensed signals. The linefeed driver does not reside with the integrated circuit. A method for monitoring power dissipation of the linefeed driver components includes the step of sampling at least one of the tip and ring signals to determine a line voltage and a line current of a selected linefeed driver component. Instantaneous power dissipation of the linefeed component is estimated and then filtered to generate an estimated junction temperature of the linefeed component. In one embodiment, the linefeed driver includes a tip fuse series-coupled to the tip line and a ring fuse series-coupled to the ring line.

Abstract: An over-power protection apparatus with programmable over-current threshold for a power converter is provided. The over-power protection apparatus further provides an over-temperature threshold for protection purposes. The over-power protection apparatus is able to achieve over-power and over-temperature protection in response to the level of the driving signal of the power converter. In addition, the programmable over-current threshold of the present invention can be adjusted in response to various load conditions.

Abstract: The remaining capacity of a battery obtained by integrating current and that obtained from the estimated open circuit voltage of the battery are weighted with a weight which varies depending on the operating conditions of the battery as needed and the weighted remaining capacities are combined into the final remaining capacity. Thus, the disadvantages of the remaining capacity based on current integration and those of the remaining capacity based on the estimated open circuit voltage cancel each other out and the advantages of the respective remaining capacities can be fully utilized. The uniform calculation accuracy can be ensured and the final remaining capacity can always be obtained with accuracy.

Abstract: In an electronic control apparatus having a one-chip microcomputer and a power output circuit, a voltage abnormality detecting circuit is provided to detect whether an output voltage of each power output circuit is set to a voltage in a predetermined range. A current abnormality detecting circuit is also provided to detect that a current flowing into each power output circuit is in an excessive current condition or in a low current condition. The microcomputer is reset when the detected output voltage or the detected current is abnormal.

Abstract: A monitoring or watchdog unit (UWE) for a current or voltage supply system, wherein a supply voltage is taken across at least one cut-out safeguard to two or more outputs, the at-least one cut-out safeguard device configured as a controlled switch device and the watchdog unit providing a cut-out signal to the at-least one controlled switch device upon changes in a voltage or current exceeding a predetermined tolerance value.

Abstract: Device miniaturization is made possible by building a battery protection circuit in a microcomputer. A secondary battery protection device comprises a voltage detection means 7 that detects a voltage of a power supply circuit 6 including a secondary battery 1, a current detection means 8 that detects a current of the power supply circuit, and a battery protection circuit 10 that shuts off the power supply circuit 6 based on a signal representing a detection made by the voltage detection means 7 or the current detection means 8 of an excess current that is generated in the power supply circuit 6, wherein the protection circuit 10 is built in a microcomputer 13.

Abstract: An apparatus, system, and method for detecting high impedance faults in electrical power lines using a composite high impedance fault detection system having a voter logic that samples the logical outputs from a plurality of independent high impedance detection systems and determines a high impedance fault if any two of the plurality of independent high impedance detection systems indicates a high impedance fault. Preferably, the plurality of high impedance detection systems include a wavelet based high impedance fault detection system having a first logical output, a higher order statistics based high impedance fault detection system having a second logical output, and a neural net based high impedance fault detection system having a third logical output. Preferably, each of the plurality of high impedance fault detection systems includes an independent high impedance fault detection application that independently detects a high impedance fault on the electrical power line.

Abstract: A discharge lamp starter includes a discharge lamp that is lit at a luminance corresponding to power supplied, and a discharge lamp start control unit. The discharge lamp start control unit, receiving a signal indicating an on state only from a first switch, causes the discharge lamp to perform daytime running light by supplying first power to the discharge lamp to start lighting, followed by supplying second power smaller than the first power to the discharge lamp to maintain lighting. Receiving a signal indicating an on state only from a second switch, the discharge lamp start control unit causes the discharge lamp to perform nighttime running light by supplying third power greater than the first power to the discharge lamp to start lighting, followed by supplying fourth power smaller than the third power and greater than the second power to the discharge lamp to maintain lighting.

Abstract: An arc fault protection device protects a branch circuit portion of an electrical distribution system. The branch circuit is connected to a load. A first sensor detects fluctuations in load current, while a second sensor detects fluctuations in line voltage. The polarities of the fluctuations are compared, and the comparison indicates whether an arc signature, potentially indicative of an arc fault, is located in the branch circuit portion or located in a remainder of the electrical distribution system.

Abstract: A circuit for detecting an overcurrent in an element in which an A.C. supply current flows, including a first comparator, assigned to the halfwaves of a first sign of the A.C. power supply, receiving on a reference input a first reference voltage setting a first one of the thresholds, a second comparator, assigned to the halfwaves of a second sign of the A.C. power supply, receiving on a reference input a second reference voltage setting a second one of the thresholds, and an input stage providing, to respective interconnected read inputs of the comparators, a voltage proportional to the voltage across the element, the stage including at least one first resistive element introducing a voltage drop between a first one of the terminals of the element and the read inputs.

Abstract: The current mirror configuration includes four branches, a biasing branch, a first comparator branch, a second comparator branch and a measurement branch. The measurement branch is connected to a pad of the IC device and a measurement current is charged on to the pad. The measurement current is mirrored from the current of the biasing branch and the measurement current is mirrored to the second comparator branch. The biasing branch is mirrored to the first comparator branch using a scale that the current of the first comparator branch is smaller than the current of the biasing branch. In case of a short-circuit, the current of the measurement branch is larger than the current of the first comparator branch.

Abstract: A control method and arrangement that monitors the condition and operating parameters of a power electronic system having power electronic devices and responds to various detected abnormalities to optimize operation of the power electronic system. The arrangement increases reliability of operation and optimizes the continuous supply of power to a load. The arrangement also includes the capability for diagnosing the parameters of the power electronic switches including drive current, drive voltage and operating temperature and for communicating the status information in a coordinated fashion.

Abstract: Adaptively controlled circuits are provided that can include an output buffer circuit, a sensing circuit, and a current conversion circuit. The output buffer circuit can include, for example, inputs, outputs and a bias control input. The sensing circuit can also include inputs and outputs. Two or more sensing circuit outputs can simultaneously turn to lower or higher level than a predetermined threshold level. The current conversion circuit can be composed of one or more set of cascaded transistors. Inputs of the cascaded transistors can be connected to outputs of the sensing circuit. The output of the cascaded transistors can be connected to foresaid bias control input of the output buffer. An output current of the current conversion circuit increases when signal level of the inputs of the sensing circuit become equal or close to each other.

Abstract: A semiconductor component has interface functions between the controller and the power components of power converters, suitable for gating semiconductor switches. In particular, the semiconductor component serves to gate IGBT and MOSFET power switches in low and medium performance three-phase bridge circuits and integrates signal processing (12), level conversion (16) and amplification (gate driver) (17), error recognition, such as short-circuit monitoring by means of VCE detection (19) and operating voltage monitoring (21) as well as error processing (15) for several power semiconductor switches. The advantages of this gating IC in comparison with hybrid or discrete solutions consist of the high integration density of various digital, analogue and driver functions which result in a reduction in the number of discrete components, which means a lower failure rate of the system and lower costs. Another important consideration is the improvement of switching characteristics thanks to monolithic integration.

Abstract: The apparatus detects an out-of-step condition following the clearing of an external multi-phase fault in a protective relay. The apparatus includes a circuit which detects the presence of an external multi-phase fault on the power line and a timing circuit for readying an out-of-step logic detection circuit in the protective relay if the external fault remains for a pre-selected period of time. An out-of-step condition is declared and a signal blocking operation of selected distance elements in the protective relay is produced if the positive sequence impedance on the line remains inside an outer protection zone boundary in the impedance plane for a selected period of time, wherein the out-of-step blocking signal continues as long as the positive sequence impedance remains inside the second boundary.

Abstract: An apparatus for detecting currents in a three-phase power transmission system includes a first detection circuit electrically coupled to a first phase of the three-phase transmission system, a second detection circuit electrically coupled to a second phase of the three-phase transmission system different than the first phase, and an event output switch electrically coupled to the first detection circuit and the second detection circuit and configured to actuate when a subsynchronous current at least one of the first phase and the second phase exceeds a pre-selected subsynchronous current setpoint.

Abstract: A method and apparatus including indicators and a Ground Fault Current Interrupter (GFCI) are provided to test the marina's power and the boats electrical system load to make sure that both are proper and safe to be inter-connected. A low voltage high impedance ground current path including an oppositely connected pair of typically four silicon diodes in series in each of the pairs, sufficient to raise the voltage to a safe level encompassing the typical combined AC ground fault and DC galvanic currents in a Marina is incorporated. This protects against low level AC ground faults present in the marina, as well as DC current due to the harbor safety ground interconnect between boats in the harbor.