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| Number | Title | Issue Date |
| 7986132 | Static var compensator apparatus A one-phase static var compensator apparatus includes a compensator string consisting of a first static var compensator connected serially to a thyristor valve. The compensator string is arranged to be connected on its first end to one phase of a transmission grid o... | 07/26/2011 |
| 7919951 | System stabilization control system In a system stabilizing control system of controlling reactive power by a reactive power compensating device according to a voltage variation of an electric power system in which a capacitor is connected to a bus through a breaker, when the bus voltage drops, the ca... | 04/05/2011 |
| 7804280 | Method and system for providing power factor correction in a power distribution system A device for providing power factor correction of a low voltage subnet that includes a low voltage feeder line that is connected to one or more low voltage power supply lines that supply power to one or more customer premises is provided. In one embodiment, the devi... | 09/28/2010 |
| 7786710 | Electric power flow control An apparatus for reactive power compensation in an ac medium voltage power network. The apparatus includes a common connection; a first branch including a first switch, and a first capacitor; and a second branch including a second switch and a second capacitor. ... | 08/31/2010 |
| 7755333 | Power system control apparatus and power system control method A SVC control section detects a bus voltage from an instrument transformer, and adjusts reactive power generated by a SVC according to the detected bus voltage. A cooperative control section generates a control command for controlling the interconnection and paralle... | 07/13/2010 |
| 7692415 | Reactive power control apparatus for AC power system A reactive power control apparatus for an AC power system includes a reactive power compensation device, a compensation capacitor device and a compensation capacitor control device. The compensation capacitor control device includes a detection voltage output circui... | 04/06/2010 |
| 7688043 | Reactive-power control apparatus and reactive-power compensator using the same In a conventional reactive-power compensator using a static reactive-power compensator (SVC), there are many cases in which the SVC is operating in a state in which it generates an amount of reactive power equivalent to a large part of its capacity. When an unforese... | 03/30/2010 |
| 7683589 | Reactive power compensator and control device therefor A reactive power compensator includes a control block with a limiter and a primary delay-control block with a limiter that set, based on an output of a voltage sensor, reactive power produced by an SVC to a predetermined value. A reactive power controller sets the r... | 03/23/2010 |
| 7638986 | Control system for static VAR compensator In a control system for a static var compensator that performs phase control of a current of a reactor for each phase by a thyristor and thus controls reactive power, a detecting unit that detects a tertiary harmonic current flowing through each phase of the static ... | 12/29/2009 |
| 7382112 | Methods and devices for input waveform control in switching power supplies The invention recognizes that filter size can be reduced substantially as power factor is permitted to deviate below unity in systematic ways. Preferred methods of the invention provide specific, computable waveforms that permit use of a minimum filter size given a ... | 06/03/2008 |
| 7368891 | Charge control method of capacitor in thyristor converter Charging time of a capacitor is shortened while avoiding erroneous firing due to distortion of a power supply voltage and sustaining an inrush current at a constant level. In the charge control method of a capacitor in a thyristor converter comprising a thyristor fo... | 05/06/2008 |
| 7352597 | Comprehensive power quality controller for substation in power system This invention disclosed is a comprehensive power quality controller for substation in the electric power system and includes a Thyristor Controlled Reactor (TCR), pure tuned passive filter Zf, additional inductor L active power filter (APF), and a coupli... | 04/01/2008 |
| 7353122 | Power converters with limited operation to conserve power and with adjustments that overcome ringing To conserve power when regulating the output voltage (Vo) of a power converter, no adjustment is made to the converter's pulse width modulation times (Tp, Ts) even if the output voltage is off target (Vtar), provided that the output voltage does not change or is mov... | 04/01/2008 |
| 7317301 | Auxiliary power supply An auxiliary power supply equipment for a high voltage installation includes a power source at ground potential, a load circuit at high potential, and a transmission link for coupling the power source to the load circuit. The power source includes a high frequency v... | 01/08/2008 |
| 7265521 | Reactive power compensation to minimize step voltage changes and transients The invention features a system and approach for minimizing the step voltage change as seen by the utility customer as well minimizing transients imposed on the fundamental waveform of a normal voltage carried on a utility power network when a reactive power source ... | 09/04/2007 |
| 7242170 | Control circuit having error amplifier for DC-DC converter and control method therefor A control circuit for DC-DC converters and a control method therefor wherein unstable operation in which output voltage fluctuates can be detected and the unstable operation be prevented from continuing are provided. The control circuit includes: an error amplifier ... | 07/10/2007 |
| 7235900 | Switching apparatus and method for varying a phase line impedance of an electric power transport line section The switching apparatus and method are provided for varying the impedance of a phase line of a segment of an electrical power line. The phase line includes n conductors electrically insulated from each other and short-circuited among each other at two ends of the se... | 06/26/2007 |
| 7196917 | PFC pre-regulator frequency dithering circuit A circuit and method of dithering the switching frequency of an off-line power factor corrected (PFC) pre-regulator. The circuitry used to dither the frequency is advantageously accomplished by taking advantage of the PWM's internal timing circuitry. This invention ... | 03/27/2007 |
| 7183752 | Connection method for a static VAR compensator A static VAR compensator has several parallel compensation components (K1–K3). To connect the static VAR compensator to an operating voltage (U) the compensation components (K1–K3) are first successively connected to the operating vol... | 02/27/2007 |
| 7148649 | Hybrid-electric vehicle having a matched reactance machine A hybrid-electric vehicle including a matched reactance machine power generation system (MRMPGS). The MRMPGS comprises a permanent magnet rotor type machine having a selected back electromotive force (BEMF) voltage value and a selected machine inductance value. The ... | 12/12/2006 |
| 7142997 | Automatic power factor corrector A computer controlled solid-state switching power factor corrector, which senses the phase angle of each phase of the current as well as the voltage and automatically aligns the current phase angle to the voltage phase angle. This power factor correction is designed... | 11/28/2006 |
| 7102343 | Methods and systems having multiple cooperating transformers Disclosed are methods, systems, and devices that include a power source having a first voltage having a first frequency, a power-consuming load(s), and a first transformer set comprising a delta-delta transformer and a first voltage controller coupled in series ther... | 09/05/2006 |
| 7095597 | Distributed static var compensation (DSVC) system for wind and water turbine applications A power generating system wherein a variable speed turbine is mounted on top of a tower or tethered underwater. The reactive component of turbine generated electrical power is corrected automatically through electronic switched power-factor capacitor banks that are ... | 08/22/2006 |
| 7091872 | Controlled power source for underground line location A transmitter for a line locator system that controls the electrical current, voltage or power applied to the target line is disclosed. Control of the electrical output of the transmitter can be achieved passively or by means of a feedback control system. A transmit... | 08/15/2006 |
| 7091703 | Dynamic reactive compensation system and method The invention features a system for connection to a utility power network. The system includes a reactive power compensation device coupled to the network and configured to transfer reactive power between the utility power network and the reactive power compensation... | 08/15/2006 |
| 7067011 | Apparatus and method for discharge surface treatment An apparatus has a green compact electrode including a material of a coating formed on a workpiece by a discharge, a power source for supplying a first voltage, a voltage detector for detecting a voltage between the workpiece and the electrode, and a pulse current g... | 06/27/2006 |
| 7053503 | Cross current compensation control system for a power system Across current compensation control system includes a cross current detection compensator having an input terminal to which a cross connection line that cross-connects the secondary sides of auxiliary current transformers (CTs) are connected, and an output terminal ... | 05/30/2006 |
| 7046016 | Potential fixing device, potential fixing method, and capacitance measuring instrument An electric potential fixing apparatus is provided that can prevent the combined total amount of electricity of a connection line between the first capacitance and the second capacitance from changing even when the electric potential of the connection line between t... | 05/16/2006 |
| 7015624 | Non-uniform thickness electroactive device An electroactive device comprises at least two layers of material, wherein at least one layer is an electroactive material and wherein at least one layer is of non-uniform thickness. The device can be produced in various sizes, ranging from large structural actuator... | 03/21/2006 |
| 7005867 | Power supply circuit and testing device A power supply circuit is provided that supplies a voltage to a load. The power supply circuit includes a power supply for generating a predetermined voltage; an electrical path for electrically connecting the power supply and the load to each other; a current draw ... | 02/28/2006 |
| 6975524 | Power factor control device A power factor correction device comprising a rectifier (10) operable to receive an AC input voltage (100) and output a rectified voltage (110), and a first analog module (20) connected to the rectifier (10) so as to receive the re... | 12/13/2005 |
| 6956305 | Voltage fluctuation compensating apparatus Voltage compensation circuits connect DC voltages accumulated in capacitors having respectively different charging voltages which are 2K (where K=0, 1, 2, . . . ) times the minimum voltage into AC voltages. The voltage compensation circuits are... | 10/18/2005 |
| 6954046 | Method and apparatus to control input to AC induction motors One embodiment of the present invention is a method to control input to an alternating current (AC) induction motor from a power supply that includes steps of: (a) determining a measure of reactive power (VAR) in two input lines to the motor during a time period; an... | 10/11/2005 |
| 6950764 | Arrangements to detect and respond to disturbances in electrical power systems A control arrangement and method is provided for detecting and responding to disturbances in electrical power systems. In a preferred arrangement, an integration is initiated that is based on a comparison of actual voltage of a source and a reference voltage. When t... | 09/27/2005 |
| 6940341 | Current control method and apparatus for active power filters An active filtering method and apparatus for controlling a current generator that sources/sinks an APF current for compensating polluting harmonics on a power line connecting a power source and a load. A feedback loop regulates the APF current by sensing the current... | 09/06/2005 |
| 6941233 | Arrangements to detect and respond to disturbances in electrical power systems A control arrangement and method is provided for detecting and responding to disturbances in electrical power systems. In a preferred arrangement, an integration is initiated that is based on a comparison of actual voltage of a source and a reference voltage. When t... | 09/06/2005 |
| 6927959 | Method for operating an electromagnetic switching device and electromagnetic switching device Switching contacts of a switching device are provided to ensure optimum service life. An optimum switching point, in terms of the load of one of the switching contacts, is determined depending on a current path that is measured during the switching process and the s... | 08/09/2005 |
| 6924627 | Method of reactive power regulation and aparatus for producing electrical energy in an electrical network A method of reactive power regulation in an electrical network in which electrical power is produced by an electrical generator preferably driven by the rotor of a wind power installation and suitably modulated by means of a compensation device between the generator... | 08/02/2005 |
| 6919712 | Excitation control device and excitation control method A reference voltage of an output terminal of a synchronous machine is set according to a reactive current output from the synchronous machine, a reference voltage of the high voltage side of a transformer, and a phase compensation transfer function to quicken attenu... | 07/19/2005 |
| 6906434 | Electric utility system with superconducting magnetic energy storage a voltage recovery device is configured to provide real and reactive power to a utility power network at a sufficient level and for a sufficient duration to recover the voltage on the utility power network within a predetermined proportion of the nominal voltage, fo... | 06/14/2005 |
