Abstract: A solid state power transformer is described for converting an input power signal at a first phase or voltage to an output signal of a second voltage or opposite phase by the use of bidirectional solid state switches switched at a high carrier frequency to produce a double-sideband, suppressed-carrier representation of the input power signal, which is then synchronously demodulated using further similar switches to produce the desired output. It is further disclosed that multiple instances of the above with relative phase-staggering of the switching frequency may be operated in parallel and activated or deactivated according to output current demand to provide maximum efficiency over a wide range of current and power levels.

Abstract: A number of DC-AC microinverters driven by separate photovoltaic sub-arrays are physically combined to use common components such as a common, common-mode choke. Each microinverter is controlled by a common switching controller to produce a portion of the desired output such that ripple on the combined output is minimized, and each microinverter produces a common mode signal on its associated sub-array equal in frequency to the desired AC output frequency.

Abstract: An improved residential electrical energy system is described based on the use of a smart load center or power distribution panel configured to select the use of utility power or power derived from storage batteries independently for each of a number of load circuits based on availability of utility power and battery charge state information.

Abstract: A remote-controlled photovoltaic string combiner is described that selects strings to be combined to a first photovoltaic output circuit or to a second photovoltaic output for the purpose of either controlling the charging of a battery connected to the first photovoltaic output circuit or for diverting current to a diversion load such as a grid-tie inverter. Strings are selected by energizing relays from one or other inverter such that when neither inverter is operating, all strings are deselected and both photovoltaic outpout circuits are de-energized.

Abstract: Smart Appliances are defined that assist in reducing energy comsumption or cost. The Smart Appliances communicate with Smart Energy sources via the power lines and in particular by injecting communications signals between the live plus neutral power lines on the one hand and the ground line on the other hand, the communications protocol allowing a power source to identify the electrical circuit to which an appliance is connected and thereby to route a selected type of power to the appliance on the correct electrical circuit for that appliance.

Abstract: Smart Appliances are defined that assist in reducing energy consumption or cost. The Smart Appliances communicate with Smart Energy sources via the power lines and in particular by injecting communications signals between the live plus neutral power lines on the one hand and the ground line on the other hand, the communications protocol allowing a power source to identify the electrical circuit to which an appliance is connected and thereby to route a selected type of power to the appliance on the correct electrical circuit for that appliance. An addressable electrical outlet is also disclosed as one form of Smart Appliance.

Abstract: A rheometer is disclosed that includes rheometry logic that is responsive to a material selection control, to an objective selection control, to material property storage, and to process parameter storage, and is operative to assist the user with a measurement using the rheometer. In another general aspect, a rheometer includes sample history storage operative to store a history that spans a plurality of different operations performed by the rheometer on a same sample.

Abstract: An advantageous method of converting solar energy from a photovoltaic array into alternating current for feeding into the electricity grid is described based on the use of an inventive rotary machine. The inventive rotary machine has a rotor and a set of stator coils which are excited in a first mode by a polyphase current derived from the solar array and simultaneously in a second, orthogonal mode by a polyphase voltage derived from the electricity grid.

Abstract: A wiring fault detector adapted specifically to address the requirement for arc fault protection specified in National Electrical Code (2011) article 690.11 comprises running at least one additional wire in parallel with the power conductors to be protected, thereby allowing evaluation at the location of a fault detector of an electrical parameter indicative of conductor integrity along its whole length. In one implementation, the additional conductor allows the voltage drop across the power conductor to be measured and verified to be small and/or noise-free. In another implementation, the additional conductor is a redundant power conductor connected in parallel with the main power conductor, allowing verification that the current flow in both the main and the additional power conductors is partitioned in an expected ratio indicative of wiring integrity.

Abstract: A method and circuit arrangement is described for start-up and shut-down of high power DC to AC inverters which limits inrush current for capacitor charging, reduces input and output relay contact stress and discharges internal capacitors upon shut down. A preferred inrush limiting component has a higher resistance when hot than when cold, such as an incandescent filament lamp.

Abstract: Profilometers for industrial metrology and other applications are described. A line is projected on a surface to be profiled. The line is scanned to build a three dimensional point cloud allowing the three-dimensional (3D) profile of the surface to be determined. In some embodiments, the line is projected by a laser system. In other embodiments, the line is projected by a digital micromirror device (DMD). In still further embodiments, multiple lines, or other patterns are projected.

Abstract: A remote-controlled photovoltaic string combiner is described that selects strings to be combined to a first photovoltaic output circuit or to a second photovoltaic output for the purpose of either controlling the charging of a battery connected to the first photovoltaic output circuit or for diverting current to a diversion load such as a grid-tie inverter. Strings are selected by energizing relays from one or other inverter such that when neither inverter is operating, all strings are deselected and both photovoltaic outpout circuits are de-energized.

Abstract: An improved residential electrical energy system is described based on the use of a smart load center or power distribution panel configured to select the use of utility power or power derived from storage batteries independently for each of a number of load circuits based on availability of utility power and battery charge state information.

Abstract: In one aspect of the invention, an improved messaging service is described comprising a server for receiving messages from a first subscriber addressed to one or more second subscribers and storing them in a scrambled form on the server along with security tokens specific to each message and recipient subscriber to facilitate unscrambling only by the intended recipient subscribers. In a second aspect of the invention, a subscriber terminal is described for precalculating security tokens corresponding to each of a number of yet-to-be received messages and transmitting the security tokens to a server for scrambling said messages even when the receiving subscriber terminal is offline. A new-message originating terminal also receives from the server a precalculated and prestored security token for each of a number of intended recipients of the new message and combines them with a locally generated security token to form header information included with the new message.

Abstract: The present disclosure relates to a mixing chamber for mixing exhaust gas with intake air in an engine. The mixing chamber has an intake air inlet, an exhaust gas inlet and a mixing post. The mixing post is located downstream of the charge air inlet and upstream of a point where the flow of exhaust gas meets the flow of intake air, said mixing post extending across the mixing chamber. The mixing post has a longitudinal axis which is oriented perpendicular to a longitudinal axis of the mixing chamber.

Abstract: A valve suitable for use as an exhaust gas recirculation valve in an engine includes a valve housing defining an interior space, a valve stem and a valve member, which may be a poppet, mounted on said valve stem. The valve member is arranged to move between open and closed positions. The valve further includes a mounting member, which may be a bush, located in the interior space, with said valve stem supported within the mounting member. The valve member includes a deflector to direct fluid away from the mounting member when the valve member is in an open position.

Abstract: A wiring fault detector adapted specifically to address the requirement for arc fault protection specified in National Electrical Code (2011) article 690.11 comprises running at least one additional wire in parallel with the power conductors to be protected, thereby allowing evaluation at the location of a fault detector of an electrical parameter indicative of conductor integrity along its whole length. In one implementation, the additional conductor allows the voltage drop across the power conductor to be measured and verified to be small and/or noise-free. In another implementation, the additional conductor is a redundant power conductor connected in parallel with the main power conductor, allowing verification that the current flow in both the main and the additional power conductors is partitioned in an expected ratio indicative of wiring integrity.

Abstract: A 1, 2 or 3-phase DC to AC converter system for reducing the cost of solar energy installations achieves cost reduction by eliminating low-frequency power transformers. One DC input polarity is selectively switched to an output terminal when the instantaneous AC output from a second output terminal is desired to be of the opposite polarity, while the other DC input polarity is used to form an approximation to a segment of a sine wave of the desired polarity at the second output terminal. A common-mode AC signal is thereby created on the balanced DC input lines at a frequency which is a multiple of 1, 2 or 3 times the AC output frequency and which is useful for detecting ground faults in the DC circuit.

Abstract: An acoustic noise canceling microphone arrangement and processor that uses a principal microphone and other microphones that may be incidentally or deliberately located in the vicinity of the principal microphone in order to derive an audio signal of enhanced signal-to-background noise ratio. In one implementation, the principal and incidental microphones comprise the microphone built into a mobile phone and the microphone built into a Bluetooth headset.

Abstract: A wiring fault detector adapted specifically to address the requirement for arc fault protection specified in National Electrical Code (2011) article 690.11 comprises running at least one additional wire in parallel with the power conductors to be protected, thereby allowing evaluation at the location of a fault detector of an electrical parameter indicative of conductor integrity along its whole length. In one implementation, the additional conductor allows the voltage drop across the power conductor to be measured and verified to be small and/or noise-free. In another implementation, the additional conductor is a redundant power conductor connected in parallel with the main power conductor, allowing verification that the current flow in both the main and the additional power conductors is partitioned in an expected ratio indicative of wiring integrity.