42384 results about "Alternating current" patented technology

The present invention provides an apparatus and a method for producing a virtual electrode within or upon a tissue to be treated with radio frequency alternating electric current, such tissues including but not limited to brain, liver, cardiac, prostate, breast, and vascular tissues and neoplasms. An apparatus in accordance with the present invention includes a source of super-cooled fluid for selectively providing super-cooled fluid to the target tissue to cause a temporary cessation of cellular or electrical activity, a supply of conductive or electrolytic fluid to be provided to the target tissue, and alternating current generator, and a processor for creating, maintaining, and controlling the ablation process by the interstitial or surficial delivery of the fluid to a tissue and the delivery of electric power to the tissue via the virtual electrode. A method in accord with the present invention includes delivering super-cooled fluid to the target tissue to cause a temporary cessation of cellular or electrical activity, evaluating whether the temporary cessation of cellular or electrical activity is the desired cessation of cellular or electrical activity, and if so, delivering a conductive fluid to the predetermined tissue ablation site for a predetermined time period, applying a predetermined power level of radio frequency current to the tissue, monitoring at least one of several parameters, and adjusting either the applied power and / or the fluid flow in response to the measured parameters.

A portable power supply device comprises a stackable battery housing locating a plurality of batteries therein and an inverter housing locating an inverter therein which is arranged to convert the direct current from the batteries to an alternating current. The inverter housing is readily separable from the battery housing such that one or more battery housings can be readily interchangeable to provide a constant supply of power and to allow a variety of charging configurations of the batteries. First electrical connectors on the battery housing and second electrical connectors on the inverter housing automatically connect the inverter to the batteries upon stacking of the inverter housing on the battery housing. Furthermore charging terminals are mounted externally on the inverter housing for ready access to connect to a charging device in a convenient manner without requiring the housings to be opened or separated form one another.

Disclosed herein is an LED light. The LED light comprises a socket electrically connected to a receptacle, and a cooling fan for forcibly circulating air. The cooling fan is received in a main body, which has a plurality of radial partition walls formed on the outer peripheral surface thereof in such a manner as to be spaced apart from one another with a gap having a slit shape for ventilation. A plurality of LEDs is attached to the outer periphery and / or the inner leading edge of the main body. A circuit board is provided to control the light such that an alternating current supplied from the socket is rectified into a direct current, which is supplied to the cooling fan and the LED.

An electromagnetic resonance non-contact power transmission device includes a transmitter including a transmitter resonance element having a mechanism for discretely or continuously varying a resonant frequency, a transmitter excitation element coupled to the transmitter resonance element by electromagnetic induction, and an alternating current source for applying an alternating current at the same frequency as the resonant frequency to the transmitter excitation element, and a plurality of receivers each including a receiver resonance element having a specific resonant frequency, a receiver excitation element coupled to the receiver resonance element by electromagnetic induction, and an output circuit for outputting an electric current induced by the receiver excitation element. Electric power is transmitted selectively from the transmitter to any of the receivers having different specific resonant frequencies by changing the resonant frequency of the transmitter.

An electrophoretic display comprises a pair of facing substrates, at least one of which is transparent, a plurality of particles and a gas between the substrates, and means for applying an electric field to cause the particles to move and thus change the electro-optic state of the display. The electric field means is arranged to increase the impulse applied to the display with increasing time since a reference time, or with increasing number of images written on the display. In another embodiment, an alternating current pulse is applied to the display, and the duration and / or amplitude of the alternating current pulse is increased with increasing time since a reference time.

Provided is a bio-sensor system which utilizes radio frequency identification technology and which includes a remote transponder in wireless communication with an implantable on-chip transponder. A power supply collects alternating current voltage pulses from an electro-active polymer generator embedded in muscle tissue for generating power for the on-chip transponder. The power supply is specifically adapted to provide a stable and precise sensor reference voltage to a sensor assembly to enhance the accuracy of measurements of a physiological parameter of a patient. The remote transponder receives data representative of the physiological parameter such as glucose concentration levels. The data is processed and transmitted to the remote transponder by the on-chip transponder. The precision and stability of the sensor reference voltage is enhanced by the specific circuit architecture of a glucose sensor to allow for relatively accurate measurement of glucose concentration levels without the use of a microprocessor.

Solar power systems and structures are mountable to a power distribution structure, e.g. a power pole or tower, which supports alternating current (AC) power transmission lines. An exemplary power generation structure is fixedly attached to and extends from the power distribution structure, and comprises a mounting rack. A solar array, comprising at least one solar panel, is affixed to the mounting rack. A DC to AC invertor is connected between the DC outputs of the solar array and the AC power transmission lines. The length of the solar array is generally in alignment with the power distribution structure, and the width of the solar array is greater than half the is circumference of the power distribution structure. The mounting rack and solar array may preferably be rotatable, such as based on any of location, time of day, or available light.

A method and apparatus for switching AC appliances and lights of residences and other automation systems through SPDT or DPDT relays connected in electrical circuit with SPDT or DPDT switch including a current sensor and / or a status sensor. The operating key of the relay and the key lever of the electric switch can each be used for operating a dedicated appliance or light, a group of appliance and lights and all appliance and / or lights including scenarios setup via the many well known two way, three way or four way light switches, by operating the switch lever or key in multi steps. The SPDT or DPDT relays are operated via RF, IR and fiber optic communicating two way signal for operating the lights and reporting statuses.

An AC LED package and circuits are disclosed along with an AC LED driver. The AC LED circuit may include as few as one LED or an array of anti-parallel LEDs driven with AC power sources and AC LED drivers at various voltages and frequencies. The AC LEDs are pre-packaged in various forms and materials and designed for mains or high frequency coupling in various forms to AC power sources, inverter type drivers or packages. The AC LED driver is a fixed frequency driver that provides a relatively constant voltage output to different size loads within the wattage limitation of the driver and in some cases is a direct mains power source.

A charging apparatus includes an antenna, a receiver, and a battery. The battery is charged by a harvester, which converts wireless energy sent by antenna to direct current and charges the battery. The harvester includes a sensor coil, a rectifier and voltage regulating filter. The wireless energy is converted by the sensor coil to alternating current (AC). The rectifier is electrically connected to the sensor coil for converting AC to direct current (DC). The voltage regulating filter is electrically connected to the rectifier to regulate DC. The battery can be charged by the wireless charge apparatus.

A modular apparatus for and method of alternating current photovoltaic power generation comprising via a photovoltaic module, generating power in the form of direct current; and converting direct current to alternating current and exporting power via one or more power conversion and transfer units attached to the module, each unit comprising a unitary housing extending a length or width of the module, which housing comprises: contact means for receiving direct current from the module; one or more direct current-to-alternating current inverters; an alternating current bus; and contact means for receiving alternating current from the one or more inverters.

An active rectifier and a wireless power reception apparatus using the same are disclosed herein. The active rectifier includes first and fourth switches, second and third switches, and a synchronization control unit. The first and fourth switches are turned on while the voltage of an alternating current (AC) input is negative, and apply the current of the AC input to a rectifying capacitor. The second and third switches are turned on while a voltage of the AC input is positive, and apply the current of the AC input to the rectifying capacitor. The synchronization control unit compensates for the delay time of the comparator for detecting zero-crossing of the AC input so as to switch the first to fourth switches.

Provided is a transmitter in a wireless power transmission system, the transmitter including a Transmission (Tx) power converter for converting a Direct Current (DC) voltage into a first Alternating Current (AC) voltage, and converting the converted first AC voltage into a second AC voltage by amplifying the converted first AC voltage, a Tx matching circuit for matching an impedance thereof with that of a receiver for receiving the second AC voltage to transmit the second AC voltage, a Tx resonator for resonating the second AC voltage into resonant waves to transmit the second AC voltage to the receiver, and a Tx controller for determining an amplification rate of the first AC voltage and controlling the Tx power converter to convert the first AC voltage into the second AC voltage according to the determined amplification rate.

A grid-connected power system includes a primary power source, a back-up power source, a DC / AC inverter and a DC / DC converter. Direct current from the primary power source is supplied to the DC / AC inverter to obtain an alternating current output supplied to a utility grid when power from the utility grid is available to power a load. The output of the inverter is supplied to a selected portion of the load when power from the utility grid is unavailable to the load. Direct current from the back-up power source is supplied to the inverter through a DC / DC converter when power from the utility grid is unavailable to the load. The DC / DC converter converts the voltage of direct current from the back-up power source to direct current having a voltage compatible with the voltage of the primary power source and the inverter. The back-up power source may be charged by the primary power source or by the utility grid. Methods of providing back-up power include converting the voltage of direct current from a back-up power source to direct current of converted voltage and supplying the direct current of converted voltage to a DC / AC inverter.

An assembly for protecting biological tissue from the effects of heating. The assembly contains a conductor in contact with the biological tissue and forming an electrical circuit comprising the biological tissue. The assembly contains a device for modifying the impedance of the electrical circuit such that, at a frequency of from about 10 megahertz to about 150 megahertz, such impedance is at least about 0.5 ohms per centimeter of length of said conductor. The assembly also contains a device for limiting the flow of current through the biological tissue such that, when the assembly is exposed to an alternating current electromagnetic field at a frequency of 64 megahertz and a magnetic field strength of 1.5 Tesla for 15 minutes, the temperature of the biological tissue does not exceed 42 degrees Celsius.

A heater system may include an alternating current supply and an electrical conductor. Alternating current may be applied to one or more electrical conductors at a frequency between about 100 Hz and about 1000 Hz. The electrical conductors may be located in a formation. The electrical conductors may resistively heat upon application of the alternating electrical current. At least one of the electrical conductors may include an electrically resistive ferromagnetic material. The electrical conductor may provide a reduced amount of heat above or near a selected temperature. Heat may transfer from the electrical conductor to a part of formation.

An apparatus and method of control for converting DC (direct current) power from a solar photovoltaic source to AC (alternating current) power. A novel DC-to-AC power converter topology and a novel control method are disclosed. This combination of topology and control are very well suited for photovoltaic microinverter applications. Also, a novel variant of this control method is illustrated with a number of known photovoltaic DC-to-AC power converter topologies. The primary function of both control methods is to seek the maximum power point (MPP) of the photovoltaic source with novel, iterative, perturb and observe control algorithms. The control portion of this invention discloses two related control methods, both an improvement over prior art by having greatly improved stability, dynamic response and accuracy.

A method to convert direct current (DC) power generated by a photovoltaic (PV) arrays to alternating current (AC) power using a PV inverter, the method includes: applying the DC power generated the PV array to the PV inverter; boosting the DC power from the PV array from a predetermined voltage level to a predetermine DC link voltage, wherein the PV array is regulated by the boosting to output a voltage at the predetermined voltage level; converting the boosted DC power to AC power, and disabling the boost of the power generated by the PV array after the array has a predetermined voltage level at least as great as the DC link voltage.

An apparatus for converting Direct Current (DC) to Alternating Current (AC), comprising a plurality of inverters, each inverter having a separate DC input adapted to be coupled to at least one solar cell defining an area of a solar panel.

A direct current arc fault circuit interrupter includes separable contacts and a trip circuit to trip open the contacts. The trip circuit includes a number of alternating current sensors structured to sense a current flowing through the separable contacts, a number of filter circuits cooperating with the AC current sensors to output a number of AC signals, a number of peak detectors cooperating with the filter circuits to output a number of peak current signals, and a processor cooperating with at least the peak detectors. The processor inputs the number of peak current signals as a plurality of peak current signals or inputs the number of peak current signals and determines the plurality of peak current signals. The processor also determines if the peak current signals exceed corresponding predetermined thresholds for a predetermined time, and responsively causes the contacts to trip open.

Control means is provided, in which the whole of the phase difference of a power waveform of each phase is matched to a value dividing a cycle of the power waveform into n-equal portions, and at the same time, the whole of the power value of each phase is controlled to be identical, so that the power conversion unit having a n-alternating current output (n is an integer numeral serving as n≧2) connected to the direct current power source and smoothing means provided between the direct current power source and the power conversion unit are made small in capacity.

A method of manufacturing a bit body, other drilling-related component, or other article of manufacture, including fabricating a particulate-based matrix and infiltrating the particulate-based matrix with a binder that includes cobalt or iron. The binder may be a cobalt alloy or an iron alloy. The particulate-based matrix may be disposed within a non-graphite mold. The particulate-based matrix and binder are placed within an induction coil and an alternating current is applied to the induction coil in order to directly heat the binder, permitting the binder to infiltrate or otherwise bind the particles of the matrix together. The molten binder may then be directionally cooled by forming a cooling zone around an end portion of the bit body and increasing the size of the cooling zone relative to the bit body. The invention also includes a bit body, other drilling-related component, or other article of manufacture which includes a particulate-based matrix that is bound together with a binder that includes iron or cobalt.