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 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: 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 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.

Abstract: A process for economically producing tabular acicular gypsum crystals in a continuously stirred reactor is disclosed. The process involves establishing a steady state atmospheric pressure reaction zone of about 20% to about 25% by weight solids of gypsum crystals in water at a temperature of about 50.degree. C. to about 60.degree. C. with continuous mild agitation. Calcium sulfate hemihydrate is fed to the reaction zone at a rate to maintain a low level of supersaturation, and a suspension of gypsum crystals in water containing crystals of a mean particle length at least greater than 45 microns is withdrawn.

Abstract: A tabular variety of acicular gypsum crystal filler is prepared by hydrating calcium sulfate dihydrate particles in a seeded continuously stirred reactor at a low level of super-saturation to obtain crystals having an aspect ratio of about 100:10:1 and average length in the longest dimension of about 100-450 micrometers. For the manufacture of paper, the obtained tabular crystal slurry may be directly added to the paper pulp before web formation to obtain a filled paper having high filler retention.

Abstract: A dc to three phase ac switched mode converter is described wherein a six switch bridge is provided to interconnect the dc source to a three-phase load. A plurality of dc sources are described, each of which employs an inductor/capacitor combination for energy storage, which stored energy is subsequently applied to the output load. The stored energy is delivered by connecting the capacitor across two legs of the three-phase load, while assuring that the third leg is invariably short-circuited back upon itself. As a result, three of the six switches in the bridge are closed at any instant to prevent any current interruption in the load.

Abstract: Storage stable oxidant-amylase pre-mix or additive formulations, when added to wheat floor, dough or bakery mixes, produce improved bakery products having fine grain and good cell structure and volume.

Abstract: Four square tooling plates each have an outer surface on which a plurality of workpieces are attached. The inner face of each tooling plate is precisely attached to a respective vertical surface of a rectangular block by means of a dowel extending into geometrically centered holes in the vertical face of the block and the tooling plate. Precise rotational alignment of the tooling plate with the block is achieved by a peg extending from the vertical face of the block into a timing hole in the tooling plate spaced from the center hole thereof. The block, with workpiece-loaded tooling plates thereon, is lowered onto a rotary table so that a geometric axis of the block is perfectly aligned with the rotational axis of the rotary table. Rotational alignment of the block with the rotary table is achieved by mating of keys extending from the bottom of a base plate of the block into keyways in the surface of the rotary table.

Abstract: A plow assembly for cutting a slit in the ground and simultaneously laying a cable in the slit as the propelling vehicle moves over the ground. The plow assembly has a shaker case containing a pair of counter-rotating eccentric weights for providing a vibratory action to the plow, additional weight means are located rearwardly of the plow and plow frame so as to reduce the amplitude of vibration at the rear end of the assembly, and the assembly also has elastomeric isolation mounts for the shaker case on the plow frame so that the resulting action of all the components is such that the plow blade pivots about a pivot point located rearwardly of the assembly and in a particularly efficient arcuate cutting movement.