Abstract:
A boost type power supply circuit for providing a DC output voltage comprising first and second semiconductor switches coupled between respective input lines and a common connection, an AC input voltage from an AC source being supplied across the input lines; first and second diodes coupled in series with respective ones of the switches; third and fourth diodes coupled across respective ones of the switches in a free-wheeling relationship with the switches, an inductance coupled in at least one of the input lines; a controller for controlling the conduction times of the switches by providing a pulse width and phase modulated control signal to each of the switches; whereby the controller turns on at least one of the switches during a positive half cycle of the AC voltage to allow energy storage in the inductance and turns off the at least one switch to allow the energy stored in the inductance to be supplied to an attached load through one of the first and second diodes and one of the third or fourth diodes; and the controller turns on at least one of the switches during a negative half cycle of the AC voltage to allow energy storage in the inductance and turns off the at least one switch to allow the energy stored in the inductance to be supplied to the attached load through one of the first and second diodes and one of the third and fourth diodes; and wherein the controller determines an on-time and an off-time of a pulse of the pulse width modulated control signal during each half cycle of the AC voltage based on at least one input without requiring sensing of the input current from the AC source; the on-time and off-time of the pulse being controlled to regulate said output voltage and to provide power factor correction of said AC input voltage.
Abstract:
A boost type power supply circuit for providing a DC output voltage comprising first and second semiconductor switches coupled between respective input lines and a common connection; an AC input voltage from an AC source being supplied across the input lines; first and second diodes coupled in series with respective ones of the switches; third and fourth diodes coupled across respective ones of the switches in a free-wheeling relationship with the switches; an inductance coupled in at least one of the input lines; a controller for controlling the conduction times of the switches by providing a pulse width control signal to each of the switches; wherein the controller turns on at least one of the switches during a positive half cycle of the AC voltage to allow energy storage in the inductance and turns off the at least one switch to allow the energy stored in the inductance to be supplied to an attached load through one of the first and second diodes and one of the third or fourth diodes; and the controller turns on at least one of the switches during a negative half cycle of the AC voltage to allow energy storage in the inductance and turns off at least one switch to allow the energy stored in the inductance to be supplied to the attached load through one of the first and second diodes and one of the third and fourth diodes. The controller determines an on-time and an off-time of a pulse of the pulse width modulated control signal during each half cycle of the AC voltage, the on-time and off-time of the pulse being controlled to regulate said output voltage and to provide power factor correction of said AC input voltage, based on either voltage sensing or current sensing.
Abstract:
The present invention provides a high-performance and small sized helical antenna element and array thereof for use in an aircraft communication system or the like, where stringent spatial restrictions and gain requirements generally apply. The performance of the array is enhanced by increasing the lateral distances between the antenna elements over a portion of the elements where the windings thereof have high current amplitude. The sweeping envelope of the array is maintained small by recovering the initial distancing over a portion of the elements where the windings thereof have low current amplitude.
Abstract:
A tubular portion apparatus (10; 100; 300; 400) to be secured and sealed to another tubular (36) is described as is a method of securing and sealing a tubular portion (10; 100; 300; 400) to an existing downhole tubular (36) such as a casing string (36). The tubular portion (10; 100; 300; 400) comprises a central portion (14), an upper (16) and a lower (18) portion adjacent to the central portion (14) along a longitudinal axis of the tubular portion (10; 100; 300; 400). The tubular portion (10; 100; 300; 400) is formed from a main material and an additional material to strengthen the upper (16) and the lower (18) portion of the tubular portion (10; 100; 300; 400).
Abstract:
Systems and methods according to the present invention provide a user interface for television control functionality. Control elements overlaid on video, DVR user interfaces and playlist creation tools, interacting with users via a pointing device, are described.
Abstract:
A method of connecting a first tubular member to a second tubular member located in a wellbore, the second tubular member including an upper end portion which has a greater diameter than the diameter of the first tubular member, the method comprising: lowering the first tubular member into the wellbore until the first tubular member is located at least within the bore of the upper end portion of the second tubular member; and expanding the first tubular member until the first tubular member is sealingly connected to the second tubular member.
Abstract:
A compression sealing apparatus for efficiently repairing leaks in pipes and storage/containment structures. The apparatus includes an externa! compression member, an internal compression member, and a compression mechanism that is operative to draw the compression members towards each other to clamp the wall containing the leak between the compression members. Sealing can be enhanced by injecting sealant material through the apparatus to sea! a cavity formed by the apparatus. The compression seal apparatus can also include an expandable insert plug that is installed in a hole in the wall of the pipe or storage/containment structure.
Abstract:
A tubular assemblyis disclosed for use in a wellbore of an oil, gas or water well, typically for landing a downhole device in the wellbore. The assembly has a sleeve adapted to receive the body of the downhole device. The sleeve is deployed into a conduit in the wellbore and expanded, so that the outer circumferential surface of the sleeve is radially expanded against the inner surface of the conduit. The sleeve has a bore with an inner circumferential surface comprising an inwardly facing formation adapted to engage with an outwardly facing formation on the body of the downhole device when the body of the downhole device is disposed in the bore of the sleeve. The sleeve is typically deployed in the wellbore at the desired location and is radially expanded by an expander device that is deployed within the bore of the sleeve. The expanded sleeve plastically deforms and retains its expanded configuration after the radial expansion force is removed from the sleeve. The sleeve provides a modular anchoring or landing point in the wellbore that can be retrospectively set in the conduit at different locations, and various downhole devices can then be deployed into the sleeves at predictable depths and a reliable connection can be made with the sleeve. The assembly can typically pass through a smaller diameter before being morphed to seal and anchor in a larger diameter.
Abstract:
A receiver device comprising: a frequency hopping radio receiver for operation according to a frequency hopping radio protocol and arranged to detect the presence of interference characteristic of a predetermined other radio protocol; and a user-alerting unit responsive to the receiver; the receiver device being configurable to actuate the user-alerting unit for alerting a user in response to the detection of interference characteristic of the other radio protocol.
Abstract:
Sulphided ion exchange resins containing primary or secondary amino groups. They may be obtained by passing a non-aqueous liquid, e.g. a hydrocarbon, feedstock containing elemental sulphur or organic, or inorganic, di-or poly-sulphides through a bed of an ion exchange resin containing primary or secondary amino groups, and so unsulphided ion exchange resins containing primary or secondary amine groups may be used to remove such elemental sulphur or sulphur compounds from liquid, e.g. hydrocarbon, feedstocks. The sulphided ion exchange resins may be used to remove elemental mercury or organic mercury compounds from liquid, e.g. hydrocarbon, streams.