118 results about "Series impedance" patented technology

A battery charger and method for a rechargeable battery pack which includes various elements in series with the cells to be charged, including but not limited to current control FETs, a fuse, current sense resistor, and internal series impedance of the series connected cells to be charged. The charging current Ichg flowing through these series elements reduces the voltage applied to the cells, thus lengthening charging time. A compensation voltage Vcomp, which when added to the nominal charging voltage for the series connected cells overcomes these voltage drops, facilitates more efficient charging while avoiding over-voltage damage to the cells. Three voltages representing substantially all of the voltage drops reducing the charging voltage on the cells, are summed, and the result is a compensation voltage which is utilized to change the nominal charge voltage for the battery to overcome these voltage drops.

An arrangement for obtaining measurable voltage signals in a utility meter includes a first connection to a phase of a power line, a second connection to a reference of a power line, a voltage divider circuit, and a series inductor. The voltage divider circuit is disposed on a circuit board and is coupled between a first node and the second connection. The voltage divider circuit has an output configured to provide measurable voltage signals to a circuit operable to generate voltage measurement information. The series inductor is disposed apart from the circuit board and is configured for current limiting. The series impedance element is coupled between the first connection and the first node.

Systems and methods for implementing line overload control via providing distributed series impedance are disclosed. One system, amongst others, comprises at least one distributed series reactor (DSR). Each DSR comprises a single turn transformer (SST) comprising two split-core sections (132), a winding (120), and an air-gap (138), the air-gap designed such that a magnetizing inductance is produced when the two split-core sections (132) are clamped around a conductor (108). Each DSR further comprises a contact switch (122) that short circuits the winding when the contact switch (122) is in a closed condition, a power supply (128) that derives power from conductor line current, and a controller (130) configured to open the contact switch when the conductor line current reaches a predetermined value, thus causing insertion of the magnetizing inductance into the conductor. The controller (130) may be further configured to close the contact switch (122) when the conductor line current drops below the predetermined value.

A multiple-stage digitally-switched impedance has one “type B” stage and at least two “type A” stages. The type A stages are cascaded between high and low reference nodes and the type B stage. Each stage comprises a string of series-connected impedances and a switch network. A decoder responds to an digital input signal by controlling the switch networks to switch selectable portions of the strings in the type A stages into a series connection with the type B stage's string, and to control the type B stage's switch network to tap its string at a location to provide a impedance corresponding to the n-bit digital input signal between the final output node and at least one of the high and low reference nodes. Each stage provides a portion of the impedance's n-bit resolution, and the sum of the bits of resolution provided by each stage equals the total n-bit resolution.

Systems and methods for providing generated power to a power grid subject to reactive power requirements. A reactive follower includes a reactive power generator coupled to a distributed power plant via a series impedance such as a step-up transformer. A reactive follower controller controls the reactive power generator on the basis of an estimated reactive power commanded by a reactive power management system and includes multi-variable control logic to determine when to increase reactive power produced by the reactive power generator based on the reactive power commanded by the distributed reactive power management system and point-of-interconnection measurements of power, reactive power, and voltage.

The invention discloses an inductive coupling type electric energy transmission device, which is formed by connecting an inverter in series with a separable transformer or weak coupling transformer. One ends of the primary side and secondary side of the separable transformer or weak coupling transformer are respectively connected in series with a resonance capacitor to enable the primary side and the secondary side of the separable transformer or weak coupling transformer to be subjected to the resonance, wherein Lk1 and Lk2 respectively express leakage inductance quantities of the primary side and the secondary side of the separable transformer or weak coupling transformer, and Cr2 and Cr2 respectively express capacitor values of resonance capacitors of the primary side and the secondary side of the separable transformer or weak coupling transformer. By adding the resonance capacitors, the invention ensures that the leakage inductances of the primary side and the secondary side and the series impedances of the resonance capacitors are zero when carrying out the frequency resonance, therefore, non-contact electric energy transmission efficiency is high. The invention also has the advantages of simple structure, convenient realization and easy popularization.

A method, device, and plurality of circuit enhancements for a rectifier system that enable reduction in lower order and higher order harmonics, without substantially reducing the rectifier's direct current output voltage. The rectifier system comprises a phase shifting primary transformer subsystem and a multi-pulse rectifier. At least one series impedance path is coupled to one of three input terminals/leads of the transformer subsystem and conducts one phase of three phase currents from a power supply to the transformer subsystem. The series impedance path provides low impedance to the 1^st harmonic and substantially higher, inductive impedance to higher harmonics of the power supply frequency. The impedance of the series impedance path at a selected frequency above a third harmonic of the power supply's fundamental frequency divided by the impedance at the fundamental frequency of the three phase power supply is substantially greater than the selected frequency divided by the fundamental frequency of the power supply.

A superconducting electrical cable system is configured to be included within a utility power grid having a known fault current level. The superconducting electrical cable system includes a non-superconducting electrical path interconnected between a first node and a second node of the utility power grid. A superconducting electrical path is interconnected between the first node and the second node of the utility power grid. The superconducting electrical path and the non-superconducting electrical path are electrically connected in parallel, and the superconducting electrical path has a lower series impedance than the non-superconducting electrical path when the superconducting electrical path is operated below a critical current level and a critical temperature. The superconducting electrical path is configured to have a series impedance that is at least N times the series impedance of the non-superconducting electrical path when the superconducting electrical path is operated at or above one or more of the critical current level and the superconductor critical temperature. N is greater than 1 and is selected to attenuate, in conjunction with an impedance of the non-superconducting electrical path, the known fault current level by at least 10%.

Systems and methods are configured for detecting and locating simultaneous faults in a distribution network having primary and secondary buses connected with two-terminal sections. The measured three-phase voltages and currents from the primary buses are received via a communication network, and the series impedances and shunt admittances and the pre-fault connectivity topology are retrieved from the storage. Simultaneous faults are determined to occur by verifying at least one phase of at least three buses having phase current mismatches determined as the differences between the measured values and calculated values using normal topology and phase voltages that are greater than a threshold. A location for each fault is determined individually if the faults are occurring at non-adjacent sections in the distribution network, or jointly if the faults are occurring at adjacent sections in the distribution network. Faulted line sections are isolated by activating switching operations for connected switches to the faulted line sections that communicatively linked to distribution system grid via communication network.

An operational amplifier arrangement having a non-linear amplifier and a linear amplifier, both having a pair of input terminals one of which is coupled to an arrangement input terminal, and both having an output terminal that is coupled to an arrangement output terminal. The output terminal of the non-linear amplifier is further coupled to the output terminal of the linear amplifier via a series impedance. The output terminal of the linear amplifier is coupled to the arrangement output terminal via a terminating impedance. The arrangement includes an active back termination arrangement coupled between the arrangement output terminal and either one of the pair of input terminals of the linear amplifier. Preferably, the linear amplifier is receiving a supply voltage that exceeds the supply voltage received by the non-linear amplifier.

A transmission tower structure for suspending from an arched crossarm a three phased circuit arranged in a compact delta configuration that improves the surge impedance loading (SIL) of a transmission line, reduces its series impedance, lowers both resistive and corona losses, and moderates electromagnetic fields and audible noise effects at the ground level—all achieved in a cost effective manner. The structure further has a low overall height and aesthetic appearance enhancing the public acceptance of the embodiments.

A supervisory method and apparatus provide for detection of “partial fault” conditions such as a relatively high series impedance in the wiring, or a relatively low parallel impedance across the wiring. A non-linear element, such as a semiconductor diode, can be used as an end of line element. The element functions as a current controlled dynamic impedance such that currents through the element can be used to detect low parallel leakage currents. Higher currents through the element can be used to detect partial open circuits.

The invention relates to a device for generating low-voltage dips in an electrical power generator (2), particularly an aerogenerator, consisting of: a circuit which is disposed between the control cabinet (4) of the generator and the output transformer (3) to the network (30), comprising a transformer (31) and a plurality of in-series impedances (11, 14, 17; 12, 15, 18; 13, 16, 19) for each phase, having switches (24, 25, 26; 20, 21, 22; 27) associated therewith; and short-circuit generator means, selectively actuating the switches as a function of the type of voltage dip required.

The invention discloses a full-bridge rectification-DC push-pull inverter AC-DC converter in the technical field of power electronic conversion, which includes a step-down circuit and a rectifier circuit connected in series in sequence, and the step-down circuit converts the high voltage through a single-phase full-control rectification circuit The power frequency AC voltage is converted into high-voltage DC voltage, and then converted into high-voltage and high-frequency pulsed AC voltage through a push-pull converter, and the voltage is stepped down by a transformer to obtain low-voltage and high-frequency pulsed AC voltage; the rectifier circuit rectifies the low-voltage and high-frequency pulsed AC voltage, The low-voltage DC voltage is obtained, and then filtered by the output filter capacitor to obtain a stable DC output. The latter stage of the circuit can be connected in series with an impedance conversion circuit to obtain a linear input impedance, and after reflection to the high-voltage AC power grid, the linear input impedance and unit input power factor of the grid side can be obtained. The invention realizes the conversion of high-voltage AC voltage to low-voltage DC voltage through a step-down circuit and a rectifier circuit, and has the advantages of fewer power devices, simple overall structure and more perfect overall performance.

The present invention is a low series impedance directional power detector, which may be used to measure either forward or reverse power in a radio frequency (RF) circuit. The directional power detector includes current detection circuitry to directionally measure current, voltage detection circuitry to measure voltage, and combining circuitry to combine the directional RF current measurements and the RF voltage measurements into a combined RF measurement, which is indicative of directional power. The current detection circuitry and voltage detection circuitry apply any phase-shifts that are needed to detect power in the direction of interest and ignore power in the opposite direction when the directional power detector is presented with a complex load.

The invention provides a stator series impedance-based double-fed wind generation set high/low voltage ride through system and method. The system comprises a DFIG stator loop connected with a power grid, wherein the DFIG stator loop comprises a filter inductor, a network side converter, a rotor side converter and a double-fed wind generation set, which are connected in sequence; a serial impedanceprotection circuit is arranged between the double-fed wind generation set and the filter inductor; the serial impedance protection circuit comprises a rapid switch and an impedance branch, which areconnected in parallel; the impedance branch comprises an impedance inductor and an impedance resistor, which are connected in series. According to the system and method, power grid comprehensive faultride through comprising high/low-voltage faults of DFIG is solved, complete compensation of DFIG stator voltage during faults is realized, the DFIG is enabled to satisfy rated working conditions, andtotal-power stator reactive support problem caused to power grids by DFIG during high/low-voltage faults is solved.

The application discloses a power transmission line parameter estimation method and system and an electric power system. The method comprises the following steps: via a multi-period PMU, voltages and currents of two ends of a power transmission line are collected, and a corresponding phasor quantity and a corresponding current phasor quantity are obtained; via the voltage phasor quantity, an actual measured value of a voltage magnitude phase angle vector is correspondingly determined; via the current phasor quantity and a pre-estimated object coefficient matrix, a mathematical estimated value of the voltage magnitude phase angle vector is calculated; a residual absolute value between the actual measured value and the mathematic estimated value is calculated; when the residual absolute value is smaller than or equal to a preset residual threshold value, the object coefficient matrix is determined as an optimal coefficient matrix; via the optimal coefficient matrix, series impedance and parallel admittance on the power transmission line are estimated. According to the power transmission line parameter estimation method and system and the electric power system, the preset residual threshold value which is obtained based on the voltage magnitude phase angle vector cannot be affected by heavy loads and light loads of the power transmission line, and therefore power transmission line parameter estimation error is reduced.