Abstract: The invention relates to a method for energy management of a process automation field device having a first module and at least a second module, wherein the field device is supplied with energy by a two conductor bus, wherein the first module, at least temporarily, consumes more energy than the two conductor bus continuously delivers, and an energy storer supplied by the two conductor bus is associated with the first module, wherein the second module is supplied continuously with energy by the two conductor bus, wherein operation of the first and second modules is so controlled that the second module has precedence over the first module and the first module is, in given cases, at least temporarily, not functional.

Abstract: The present invention relates to a method for generating a current differential protection supernode based on an electrical topology of a regional distribution network, which belongs to the fields of automation of electrical power systems and relay protection. The present invention generates several supernode differential protection elements, i.e., differential protection objects, and backup differential protection elements by circularly using a depth-first search method according to the inputted branch-node associative data table reflecting the electrical topology of the distribution network. the present invention can accurately located and quickly isolate the faults in the distribution network system, reduce the probability of power cut in the non-fault lines, reduce the coverage of power cut, quickly reconstruct and self-heal the distribution network, and solve the effect of the distributed access system on the distribution network protection.

Abstract: A transmitting and receiving electrode system, and power transmission method using the same are provided. The transmitting and receiving electrode system includes: a voltage/current detection unit measuring a voltage and a current in real time while power is being transmitted between first and second electrodes; a controller calculating a variable element value based on the voltage and current values transferred from the voltage/current detection unit; and a variable element unit converting a variable element under the control of the controller to adjust an impedance of a power source.

Abstract: There are provided a power factor correction circuit capable of transferring extra power to a ground before performing switching for a power factor correction to thereby reduce a switching loss generated in switching for a power factor correction, and a power supply device and a motor driving device having the same. The power factor correction circuit includes: a main switch switching input power to adjust a phase difference between a current and a voltage of the input power; and an auxiliary switch switched on before the main switch is switched on, to thereby form a transmission path for extra power of the main switch.

Abstract: Disclosed is a multiphase converter comprising multiple phases (11 to 16), each of which can be triggered using switching means (21 to 26), at least one phase (11) being magnetically coupled to at least three other phases (12, 14, 16) by corresponding coupling means (31, 36, 37).

Abstract: Disclosed is a multiphase converter comprising multiple electric phases (11 to 16), each of which can be triggered using switching means (21 to 26). Coupling means (31, 36, 37) are provided which magnetically couple at least one first phase (11) to at least two other phases (12, 14, 16). At least two coupling means (31, 36, 37) are provided for magnetically coupling one of the phases (11) to at least two other phases (12, 14, 16), at least one of the two coupling means (37) having less inductance than the other coupling means (31, 36).

Abstract: An active phase angle correction circuit which corrects the phase angle between voltage and current in an AC supply varies the capacitive loading of the AC mains to reduce the phase angle to near zero by detecting the phase angle, reactively and resistively loading the AC mains in steps until the phase angle is at a desired level close to zero, and then maintaining or incrementally adjusting the loading. The applied loading may be continuously switched in and out at a rate much greater than the mains supply frequency.

Abstract: A device for improving efficiency of an induction motor that soft-starts the motor by applying a voltage to the motor that is substantially less than the rated voltage then gradually increasing the voltage while monitoring changes in current drawn by the motor, thereby detecting when maximum efficiency is found. Once maximum efficiency is found, the nominal motor current is found and operating ranges are set. Now, the voltage to the motor is increased/decreased by measuring the phase angle between the voltage and the current to the motor and increasing the voltage when the phase angle is less than a minimum phase angle (determined during soft-start) and decreasing the voltage when the phase angle is greater than or equal to the minimum phase angle as long as the voltage does not fall below a minimum voltage determined during soft-start.

Abstract: Disclosed is a toroidal core current transformer comprising a primary conductor which penetrates the toroidal core and a secondary winding that is wound around the toroidal core. A measuring shunt (RSh) or a load (Zb) is provided at the secondary end. In order to compensate the phase error (f) between the primary current (IP) and the secondary current (Is), a compensation circuit (K) whose capacity (C) is measured substantially according to equation (I) or (II) is provided at the secondary end. In equation (I) or (II), C represents the capacity of the compensation circuit, ? represents the radian frequency, ? represents the phase error between the primary current and the secondary current, Rsh represents the resistance of an optional measuring shunt, and Zb represents the impedance of an optional load.

Abstract: There is provided an inverter device capable of simplifying the circuit structure, lowering the cast, and downsizing of the device. The inverter device detects a switching change of an inverter by a pulse and is equipped with a pulse signal detector capable of detecting a motor residual voltage or a phase and a detector for detecting a residual voltage or a phase. The inverter device includes a voltage detector, a circuit for detecting a pulse signal based on a comparison between a phase voltage detection value per one phase output from the voltage detector and a first reference voltage value, a circuit for detecting a line residual voltage based on phase voltage detection values of two phases output from the voltage detector, and a circuit for detecting a line phase based on a comparison between the line residual voltage and a second reference voltage value.

Abstract: An induction motor control device includes an inverter circuit for driving an induction motor by outputting a command voltage, a current detector for detecting an output current, a magnetic flux estimation observer for generating an estimated magnetic flux, an estimated current, and a phase command for the motor using the command voltage and the output current, a primary angular speed estimator for estimating a primary angular speed using the estimated magnetic flux, a slip compensator for calculating a slip angular frequency using the output current, a first angular speed estimator for estimating a first angular speed using the primary angular speed and the output current, a second angular speed estimator for estimating a second angular speed using the output current, the estimated magnetic flux, and the estimated current, and a resistance estimator for estimating a secondary resistance value of the motor using the first and second angular speeds.

Abstract: A phase shift control method for a boost converter and circuit implementation comprises a master phase and at least one slave phase. A master-phase inductor current flowing through the master phase has a master-phase charge time interval and a master-phase discharge time interval; a slave-phase inductor current flowing through the slave phase has a slave-phase charge time interval and a slave-phase discharge time interval. The method comprises: calculating an ideal switching timing whereat the slave-phase inductor current descends to a zero-current judgment value; obtaining a physical switching timing whereat the slave-phase charge time interval starts; calculating a conduction timing error between the physical switching timing and the ideal switching timing; determining the time length of the slave-phase charge time interval in the same cycle according to the conduction timing error and the master-phase charge time interval.

Abstract: A power switching control apparatus for acquiring pieces of making operation time information of individual phase switches more precisely according to loads and making instants. Making operation time information detecting means outputs the making operation time information of at least one of individual phase switches on the basis of the motion of the movable contact of the phase switch, and outputs the making operation time information of at least another of the individual phase switches on the basis of the phase current of the phase switch. Moreover, the making operation time information detecting means outputs the making operation time information ITA, ITB and ITC of an A-phase switch, a B-phase switch and a C-phase switch individually on the basis of either the detected output of a contact operation sensor and the detected output of a phase current sensor.

Abstract: Provided is a voltage regulator that is excellent in transient response characteristics even if a resistance of a resistor in a phase compensation circuit is large. In the voltage regulator, the resistor of the phase compensation circuit is so configured as to change the resistance thereof according to a voltage across both ends of the resistor. In a transient state in which an output voltage of an error amplifier circuit changes, the resistance of the resistor in the phase compensation circuit is decreased, to thereby improve the transient response characteristics of the voltage regulator.

Abstract: A circuit for controlling two switches assembled in anti-parallel, comprising in series between two terminals of the anti-parallel assembly, two identical control stages respectively dedicated to each switch and between which is interposed a common impedance setting a phase angle for the turning-on of the switches, each stage comprising: a controllable current source for providing a current to a control electrode of the concerned switch; a capacitor for storing a supply voltage of at least the current source; an element of activation/deactivation of a the current source according to the voltage across the stage capacitor; and an assembly for discharging the capacitor.

Abstract: A method for dimmable control of a multiple output EL lamp driver is disclosed. The multiple output EL lamp driver has a power converter. A plurality of EL lamps are provided wherein one terminal of each EL lamp is coupled to a single common terminal. A plurality of half bridge circuits are provided wherein each circuit has an output impedance. One half bridge circuit is coupled to the single common terminal and each remaining terminal of each EL lamp is coupled to a separate individual half bridge circuit. A logic circuit is coupled to each of the half bridge. An oscillator is coupled to the logic circuit. The method comprises: minimizing the output impedance of the half bridge circuit coupled to the single common terminal to prevent to brightness crosstalk between EL lamps; selecting output impedances of remaining half bridge circuits to produce rounded waveforms across terminals of the EL lamps; and manipulating a drive waveform of one of the plurality of EL lamps to control brightness.

Abstract: Switched power converter with hold-up time and harmonics reduction connected to an AC power mains through a first rectifier means (13) and connected to conversion means (19) supplying a regulated voltage. An energy storage means (16) connected in parallel with the rectifier means (13), absorbs or supplies current to the conversion means (19), by adapting the conducting periods of two switching devices in such a way that determines the voltage level on the storage means (16) and assures a sinusoidal current at input terminals (11, 12). The two switching devices are switched in a complementary manner by means of a first control means included in the energy storage means (16).

Abstract: An amplitude and phase cancellation circuit for modifying or reducing the phase and amplitude of a signal includes a quadrature hybrid having four ports. A first port receives an input signal and a fourth port outputs an output signal derived from the input signal. The remaining two ports are connected to circuit sections having tuneable and adjustable components for selectively varying the phase and amplitude of the output signal. When the output signal is combined or mixed with an external signal, the circuit allows for selective adjustment or cancellation of components of the external signal by generating an output signal having a phase angle opposite to and amplitude equal to the external signal components for which cancellation is desired.

Abstract: A control circuit for an electrical appliance having an inductive load includes a signal conditioning element, a control element, a power conditioning element, a power adjustment element, and a switching element. The control circuit is sensitive to input received from a sensor which in turn is sensitive to a touch on an outside of a conductive casing of the appliance or a sharp sound. A separate touch pad is used if the appliance has a non-conductive casing. The load is typically a motor for driving a fan unit. The fan unit may be used either independently or as part of an appliance such as a humidifier, dehumidifier, heater, or air purifier.

Abstract: A local signal of preset frequency is supplied to an input terminal of a signal input section. The local signal is supplied to a control input terminal of a variable current source, a current corresponding to the local signal is output from the variable current source, and the current is supplied to a phase shifting section. The phase shifting section includes an integrator constructed by a capacitor and a resistor connected in series and a differentiator constructed by a resistor and a capacitor connected in parallel. As parallely connecting the phase shifting circuit with a linear element of which the signal input section consists, the phase shifting section outputs first and second output signals which has the same frequency as the local signal and whose phases are different from each other by 90.degree.. The output signals of the phase shifting section are output to the next stage via an orthogonal signal output section constructed by current source and transistors.

Abstract: During operation, DC arc furnaces (8) produce undesired reactive load fluctuations which are compensated by means of a power factor compensator (31). An AC power controller (28) of the power factor compensator (31) is controlled as a function of a stabilization striking angle signal (.alpha..sub.st) which is controlled in accordance with the reactive power of filter branches (4, 4') by a function generator (26) as a function of a desired reactive power signal (Q.sub.des8), of a reactive power actual value signal (Q.sub.8) of the arc furnace (8) and of a filter reactive power signal (Q.sub.F). The desired reactive power signal (Q.sub.des8) is formed by means of a phase-angle controller (35) as a function of a total current intensity (i.sub.33) which, in addition to the current actual value (i.sub.act) of the arc furnace (8) also comprises the current of the filter branches (4, 4') and that of any auxiliaries.

Abstract: A circuit for inputting an ac signal to a digital processor includes a capacitor connected to the input and ground. A rectifier, preferably a transient voltage suppression device, permits the capacitor and also the stray capacitance which couples false signals to the input lead, to charge to one polarity only. A shunt resistor discharges the capacitor on half cycles of opposite polarity, but there is no discharge path for the stray capacitance which therefore charges up to block steady state false ac signals. Series resistors between the rectifier and the input determine, together with the shunt resistor, the minimum input signal level and increase the over surface breakdown voltage to protect the input from transient voltage conditions. A resistor connected between the series resistors and the rectifier, and to ground determines the charging rate of the stray capacitance. The TVS device provides high transient voltage withstand and breaks down without damage in the event of large transients.

Abstract: In a method for monitoring and/or control of a plant component (4A, 4B, 4C, 4D) connected to an electric power network (N1, N2), for example a tunable filter for harmonic filtering or a capacitor bank for generating reactive power in a converter plant for high-voltage direct current, products of, respectively, a voltage (U.sub.A, U.sub.B, U.sub.C, U.sub.D) occurring in the plant component and of a current (I.sub.A, I.sub.B, I.sub.C, I.sub.D, I.sub.AC) flowing therethrough are formed, and sine and cosine signals, the frequencies of which are equal to the product of the ordinal number of a selected tone and a fundamental frequency associated with the power network, the products are integrated and the phase difference (.phi..sub.un -.phi..sub.In) and/or the amplitude value (SUn, SIn, respectively) between/for the components of the voltage and the current of the selected tone are formed by quotient generation, multiplication, and summation of the integrated products.

Abstract: A transmission line power flow control system and method selectively reverses power flow direction and controls power flow level over a transmission line. A capacitor having a variable capacitive impedance is selectively inserted in series with the line. The capacitor has a maximum capacitive impedance magnitude which exceeds the magnitude of the inductive impedance of the transmission line. A switching device in parallel with the capacitor inserts and removes the capacitor from the line. The capacitor maybe inserted and removed in a stepwise fashion using several modules, or in a gradual fashion by using inductors in series with the modular switching devices. In response to measurements of power flow parameters, such as line current and line to ground voltages, a controller controls the switching device(s) to selectively vary the net impedance of the transmission line to control the direction and magnitude of power flow therethrough.

Abstract: A compensating circuit arrangement for a power transmission system for rapidly inserting capacitance into a transmission line for desired portions of cycles of the operating frequency of the system, has first anti-parallel connected thyristors in series with a capacitance and second anti-parallel connected thyristors in parallel with the series connected first thyristors and the capacitance. A control responsive to a variable in the system, and related to system reactance, switches desired thyristors on at desired times during a cycle of operating frequency to introduce controlled amounts of capacitance into the power transmission system.

Abstract: A subsynchronous resonance mitigation system, including a method and apparatus, for damping undesirable subsynchronous resonance oscillations in a generator, which, if left unchecked, may damage the shafts of a turbine-generator set. A remote coupling apparatus, such as a thyristor controlled series capacitor (TCSC) system, a sourced inverter device, or a static phase shifter, is coupled to the generator by a transmission line. In response to a firing command, the coupling apparatus introduces subsynchronous resonance mitigating currents into the transmission line. Sensors monitor power line parameters and/or the generator speed, and in response thereto, a higher-level controller generates a voltage command. A vernier controller responds to the monitored power line parameters and the voltage command to provide the firing command to the coupling apparatus.

Abstract: A faster, more controllable phase-shifting transformer system is provided, along with a method of retrofitting and upgrading a preexisting system for faster operation, and a method of applying a desired phase shift to the voltage on a polyphase transmission line. A phase-shifting transformer set has series and regulating transformers coupled together by a switching network, An optional modulator modulates the phase shift voltage about a nominal level established by the switching network. The modulator may be a variable susceptance switched inductor or a switched capacitor, or a variable source device, such as a voltage source inverter device or a synchronous condenser. A thyristor augmented switching network may have a pair of thyristor valves augmenting a reversing switch, or a thyristor augmented load tap changer for varying the phase shift discreet step magnitude.

Abstract: Phase shifter to which are applied two signals in a phase opposition (v, -v) is constituted by a first series circuit of a resistor and a capacitor (R.sub.1, C.sub.1), and a second series circuit of a resistor and a capacitor (R.sub.2, C.sub.2). So that neither the relative amplitudes nor the relative phases of all the signals used at the outputs (5, 6, 7, 8) are degraded by the impedance of the stages that follow, the phase shifter includes a first network of a resistor and a capacitor connected in parallel (C.sub.3, R.sub.3), and a second network of a resistor and a capacitor connected in parallel (C.sub.4, R.sub.4). Both the four resistors and the four capacitors of the phase shifter are each substantially equal in value.

Abstract: A variable dual phase shifter for simultaneously varying the phase shifts in two signal paths by equal and opposite amounts comprises two 90.degree. hybrids in the respective signal paths, and a pair of substantially identical transmission lines connecting output ports of one hybrid to output ports of the other. A number of variable-impedance radio-frequency devices, which are preferably p-i-n diodes, are connected to the transmission lines at positions spaced apart along the length of the lines, the positions on one line corresponding to those on the other line. The impedances of the devices are controlled to create a reflective termination at a selected position on one line and a reflective termination at the corresponding position on the other line, so that the phase shift applied to each signal is determined by the distance of the reflective termination from the respective hybrid. The devices may be arranged in pairs, each device of a pair being coupled to a respective one of the transmission lines.

Abstract: A phase shifter includes first and second series-connected resistor circuits each including first and second resistors and each interposed between each one of two input terminals and each one of two output terminals, and includes capacitors each interposed between each one of medium points of the series-connected circuits and each one of two output terminals. The phase shifter also establishes a relationship of RgRl=R.sup.2 where the value of the first resistor is Rg/2, the value of the second resistor is R, and the output resistance between the two output terminals is Rl.

Abstract: In a hybrid switched-capacitor controlled-reactor static VAR compensator including a fixed-capacitor, hysteresis on switching-OFF a switchable capacitor of the capacitance bank is performed with a minimal fixed-hysteresis at the entrance of the standby region and with a temporary and variable-hysteresis in relation to any operating point in the standby region whenever maintaining the capacitor OFF is required. Since the fixed-hysteresis operates most often to prevent switching-OFF of the capacitor while the variable-hysteresis will operate less often, the losses at standby are minimized during thyristor-switched capacitor operation through most of this.

Abstract: Power conditioning apparatus exhibiting enhanced stability with respect to lagging phase angle conditions incurred in conjunction with load derived transients. The apparatus employs a synthesizer network structured having a regulator which is fashioned as a non-linear saturable transformer in parallel with a capacitor bank and which is supplied from a utility line source through input inductors. The saturable transformer components and associated capacitors form a ferroresonant circuit wherein the reactive components operate beyond the knee of a conventional magnetization curve. To develop the stiffness to suddenly lagging phase angle otherwise encountered with such synthesizers, a induction or synchronous motor is employed at the output of the regulators which operates in essentially no load fashion to create a stable output in the presence of load transient phenomena. An odd harmonic trap arrangement is provided to assure stability under severe operational conditions such as single phasing.

Abstract: A coordinate reader comprises first and second conductor loops each having an electrical conductor so that electrical conductors of the respective conductor loops are juxtaposed on an electrically insulating board, a cosine function generator connected to one of the first and second conductor loops, a sine function generator connected to the other of the first and second conductor loops, a cursor incorporating a magnetic flux detecting coil for detecting magnetic fluxes generated in the conductor loops excited by the cosine and sine function generators, and a processor. The processor processes and controls operations of the aforementioned components to detect coordinates of the cursor.

Abstract: An automatically variable all-pass circuit includes a variable impedance circuit for changing the shape of the phase characteristic of the output signal of the all-pass circuit as a function of the amplitude of the output signal of the circuit.

Abstract: Phase shifters are used in meshed, multi-phase power supply systems for improving their transmission stability and for load-flow regulating purposes. In order to be able to use a less costly exciter transformer of lower rating or the tertiary or compensation winding of a system coupling transformer for generating intermediate-circuit voltages as a function of system input voltages, a resonant circuit is provided between the exciter transformer and an auxiliary transformer. In this resonant circuit consisting of series-connected capacitors and inductive resistances which are connected to taps between these capacitors and can be switched in and out by means of alternating-current switches, tap voltages are generated which are supplied to the primary windings of the auxiliary transformer. At the secondary windings, connected in series with phase conductors of the auxiliary transformer, auxiliary voltages occur which are superimposed on the system input voltages and effect the desired phase shifts.

Abstract: A two dimensional digitizing system comprises two systems at right angles to each other, comprising two conducting grid structures each having three terminals A, B, and C, with the grid conductors running parallel to the X axis in one system and the Y axis in the other, and a cursor coil. When the cursor coil is excited with an alternating current, voltages e.sub.ab, e.sub.bc and e.sub.ca are induced between the terminal pairs AB, BC and CA respectively, whose amplitudes are functions of the position of the cursor coil relative to a cartesian co-ordinate system defined by said X and Y axes.The voltages e.sub.ab, e.sub.bc and e.sub.ca from each system are phase shifted and summed to provide two single signals e.sub.x and e.sub.y whose phase shift from a reference signal derived from the cursor coil excitation is a linear function of cursor coil displacement along the X and Y axis respectively.The phase shifting is accomplished by a passive network connected to the three grid winding terminals.

Abstract: A polyphase line voltage regulator which uses polyphase pulse saturable ferroresonant reactors in series with three separate and equal input chokes. The line voltage regulator is particularly suitable for computer operations which impose a variable current demand on the power source. The input chokes are directly coupled with an unregulated a.c. source and are provided with controlled non-linearity. LC tuned circuits inhibit the second and third harmonics from the regulated a.c. voltage. An isolation transformer is connected across the polyphase pulse saturable ferroresonant reactors and delivers a voltage regulated a.c. output voltage to a load.

Abstract: The delivery of alternating current from a source to a load, especially a sistance heater, is accurately controlled as a function of temperature through the employment of a bidirectional solid state switch. A full-wave power control for the solid state switch includes a temperature probe comprising one or a combination of voltage and temperature sensitive devices.

Abstract: This reference source provides a current which is of relatively high magnitude and which leads the voltage by substantially 90.degree.. It includes a reference capacitor which is highly stable and pure but of low capacitance, and a power capacitor which has a high capacitance. The capacitors are connected together at one end for coupling to a voltage source. A current comparator compares the currents flowing through the reference capacitor and the power capacitor, and provides a difference signal. A circuit generates a current in response to the difference signal and adds the generated current to the current through the power capacitor resulting in a current having a waveform and phase substantially identical to the reference capacitor current which leads the voltage source voltage by substantially 90.degree..