Abstract: Implantable medical systems enter an exposure mode of operation, either manually via a down linked programming instruction or by automatic detection by the implantable system of exposure to a magnetic disturbance. A controller then determines the appropriate exposure mode by considering various pieces of information including the device type including whether the device has defibrillation capability, pre-exposure mode of therapy including which chambers have been paced, and pre-exposure cardiac activity that is either intrinsic or paced rates. Additional considerations may include determining whether a sensed rate during the exposure mode is physiologic or artificially produced by the magnetic disturbance. When the sensed rate is physiologic, then the controller uses the sensed rate to trigger pacing and otherwise uses asynchronous pacing at a fixed rate.

Abstract: In various implementations, string inverter circuit configurations are provided that allow for increased device lifetimes. In one implementation, for example, an inverter includes a pair of inverter input terminals. A ground-balancing converter module is coupled between the pair of inverter input terminals and ground. The ground is disposed between each of the pair of inverter input terminals. A plurality of converter modules is coupled to an output of the ground-balancing converter module, each of the plurality of converter modules providing an output ac phase of the inverter. In another implementation, a method of controlling an inverter is provided. The method includes controlling a voltage level of each terminal of the pair of inverter input terminals to have equal magnitudes and opposite polarities with respect to a ground voltage.

Abstract: A control architecture that overcomes limitations of conventional ac-dc converters and enables bidirectional active and reactive power processing is provided. In one implementation, for example, this may be achieved through the use of unrectified sensed ac signals in the generation of the control commands for the converter. This control architecture, in this example implementation, eliminates or at least reduces zero crossing distortions in the ac current of the converter even with relatively low bandwidth controllers. The concept can be applied to different power stage topologies.

Abstract: A photovoltaic device includes at least one photovoltaic cell and a DC/DC converter electrically coupled to the at least one photovoltaic cell. The at least one photovoltaic cell and the DC/DC converter are integrated into a photovoltaic package.

Abstract: A photovoltaic device includes at least one photovoltaic cell and a DC/DC converter electrically coupled to the at least one photovoltaic cell. The at least one photovoltaic cell and the DC/DC converter are integrated into a photovoltaic package.

Abstract: A photovoltaic device includes at least one photovoltaic cell and a DC/DC converter electrically coupled to the at least one photovoltaic cell. The at least one photovoltaic cell and the DC/DC converter are integrated into a photovoltaic package.

Abstract: A photovoltaic device includes at least one photovoltaic cell and a DC/DC converter electrically coupled to the at least one photovoltaic cell. The at least one photovoltaic cell and the DC/DC converter are integrated into a photovoltaic package.

Abstract: The present invention relates to an apparatus and processing method for drying lumber, for example two-by-four studs in an environment in a kiln in a manner to avoid warping, including crook, bow, cup and twist. The lumber pieces are stacked in a normal manner with stickers for providing air flow between courses of the lumber pieces, and the stack is dried while a horizontal force is provided to the respective courses of lumber in the stack to hold the individual pieces of lumber in edge to edge contact throughout the drying, equalizing, conditioning and cooling process for first drying of lumber, redrying of lumber or in a treatment process for removing warp from previously dried lumber. A vertical force comprising a weight or other force generating device can be also applied to the stack of lumber to augment the overall reduction in warpage if so evidenced.

Abstract: A photovoltaic device includes at least one photovoltaic cell and a DC/DC converter electrically coupled to the at least one photovoltaic cell. The at least one photovoltaic cell and the DC/DC converter are integrated into a photovoltaic package.

Abstract: A photovoltaic device including at least one photovoltaic cell and a transformerless inverter electrically coupled to the at least one photovoltaic cell. The at least one photovoltaic cell and the transformerless inverter are integrated into a photovoltaic package.

Abstract: A cutting tool for use on earth working and land clearing equipment includes a working body portion having a continuous slot formed transversely therethrough in open communication with the first end and an exterior surface thereof. A cutting insert having a V-shaped notch formed in the front cutting end thereof is positioned and rigidly secured within the slot. A mounting shank extends outwardly from and is attached to the second end of the working body portion for enabling attachment of the cutting tool to a tool holder used on such earth working and land clearing equipment.

Abstract: A cutting tool for use on earth working and land clearing equipment includes a working body portion having a cavity disposed therein which begins at a peripheral edge of a first end and extends inwardly towards a second end of such working body portion. The cavity is provided with a cutting portion disposed at an acute angle about such peripheral edge. A mounting shank extends outwardly from and is attached to the second end of the working body portion for enabling attachment of the cutting tool to a tool holder used on such earth working and land clearing equipment. At least one pin member engaging the complimentarily aligned grooves within an aperture of the tool holder and an outer surface of the shank portion is used to securely retain the cutting tool within the tool holder.

Abstract: The present invention provides a method for producing a controlled output voltage for a switching power converter under current control using pulse width modulation, the switching power converter including a predictive digital current-mode controller and a digital pulse width modulator. The current control results in an unstable output voltage, and the pulse width modulation method is selected to eliminate the instability of the output voltage.

Abstract: An apparatus for cutting and clearing brush, trees and land debris includes a housing adapted for mounting to a carrier and a rotor assembly with a predetermined plurality of cutting tools mounted for rotation within the housing and driven by a gearbox and a motor combination. A tubular frame mounted to the housing above the rotor guides pushes the material for contact with the cutting tools mounted on the rotor. A movable front flange provides directional control for processed material discharge. A plurality of cutting tools are attached to a bottom portion of the housing for decreasing the size of the processed material. A plurality of a plate like members are attached to the bottom portion of the housing for limiting a size of the unprocessed material and for guiding the material into the housing for contact with stationary and rotating cutting tools. At least one deflector within the housing reduces the speed of the processed material for increased contact with the cutting tools.

Abstract: A technique for end-grain creation is employed for obtaining rapid and uniform drying of lumber while simultaneously reducing warp. The stability-kerfing responsible for the improved drying of the lumber decreases the edgewise bending strength by less than ten percent, a loss readily recovered due to the ability of stability-kerfing to achieve lower and more uniform moisture contents than those realized in the contemporary drying of lumber. This overall improvement in moisture content greatly increases the edgewise bending strength for stability-kerfed construction lumber by comparison to that for contemporary construction lumber. Its improved moisture condition at the time of entry into the marketing stream also fosters future dimensional stability compared to that for contemporary lumber. The required stability-kerfing is easily accomplished by the specialized implementation of existing saw equipment and associated technology into the contemporary processing lines.

Abstract: A system and method for efficiently capturing electrical energy from a variable-speed generator are disclosed. The system includes a matrix converter using full-bridge, multilevel switch cells, in which semiconductor devices are clamped to a known constant DC voltage of a capacitor. The multilevel matrix converter is capable of generating multilevel voltage wave waveform of arbitrary magnitude and frequencies. The matrix converter can be controlled by using space vector modulation.

Abstract: A system and method for efficiently capturing electrical energy from a variable-speed generator are disclosed. The system includes a matrix converter using full-bridge, multilevel switch cells, in which semiconductor devices are clamped to a known constant DC voltage of a capacitor. The multilevel matrix converter is capable of generating multilevel voltage wave waveform of arbitrary magnitude and frequencies. The matrix converter can be controlled by using space vector modulation.

Abstract: This patent disclosure describes new non-linear carrier-pulse-width modulators for control of high power-factor boost rectifiers. In the new modulators, the switch duty ratio is determined by comparing a signal derived from the main switch current with a periodic, nonlinear carrier signal .nu..sub.c (t, .nu..sub.m). The shape of the carrier is selected so that the resulting input current follows the input voltage, as required for unity-power-factor rectification. A slowly-varying modulating input .nu..sub.m can be used to adjust the power level and to regulate the output dc voltage. The controller based on the new non-linear-carrier modulator has a number of advantageous properties: sensing of the input line voltage is eliminated; for current shaping, only sensing of the power switch current is needed; current shaping does not require an error amplifier with feedback loop compensation; the multiplier in the voltage feedback loop is eliminated; and the converter operates in the continuous conduction mode.

Abstract: A hollow light weight pole like structure suitable for use as a utility pole, column or log building member is made of a plurality of wood strips glued edge to edge forming a hollow interior core, with at least one layer of high strength veneer material glued to the exterior of the wood strips with the veneer grain running parallel to the length. The layer of veneer increases the strength, distributes bending stresses uniformly, provides greater decay resistance than ordinary glued hollow poles, and increases the service life. The veneer can be made in several layers forming a continuous overwrap without longitudinally extending gaps that expose the interior wood strips to weather or splitting.

Abstract: A power supply for providing a single level dc output voltage, with input power factor correction, from a wide range of ac input voltages commonly available worldwide. The power supply rectifier circuit can be configured as a full wave bridge for high line voltage inputs and as a voltage doubler for low voltage inputs. Output voltage regulation and power factor correction are accomplished by a high frequency boost circuit having two inductors connected in parallel for the low input voltage configuration and in series for the high input voltage configuration. The high frequency switching semiconductor components are connected in a series circuit which limits their voltage requirement to one-half the output voltage.