Abstract: A monitoring device for monitoring a screw joint of an object includes a base plate to be attached to the object and a top plate to be attached to one part of the screw joint, wherein the base plate and the top plate are positioned parallel to and on top of each other and wherein both plates each includes at least one electrode that capacitively interact with each other. The monitoring device is characterized in that the electrodes are shaped and positioned such that at least one electrode of one of the plates interacts with at least two different electrodes of the other one of the plates depending on the rotational position of the plates relative to each other. A monitoring arrangement having at least one monitoring device of this kind and a monitoring method are also provided.

Abstract: The invention is a device and method for eliminating core excitation losses in a distribution transformer when the transformer is not supplying power to loads. The invention consists of sensors, a control circuit, a user interface and a power contactor. The power contactor is connected on the line side of a transformer and is opened or closed automatically based on preprogrammed time or load criteria determined by the control circuit. In one operational mode and when the transformer is disconnected from the line, the control board generates low power pulses at the transformer load connection points in order to “search” for loads. If a load is detected, the transformer is reconnected by way of contactor closure. If the transformer load drops to zero, for a predetermined amount of time, the transformer is again disconnected and the pulsed load search is reestablished.

Abstract: A combiner circuit and voltage protection circuit is disclosed. A plurality of photovoltaic sources is provided. A set of fuses, each having one side coupled to one of the plurality of photovoltaic sources is provided. A set of contacts, each having one side coupled to the other side of one of the fuses is provided. The other side of the contacts are coupled together to combine the output of the photovoltaic sources to an output interface, the output interface being coupled to the load. A set of diodes are each coupled to each of the set of fuses and form a current path around the set of contacts. A transistor is coupled to each of the diodes and the load interface. The transistor has an on state completing the flow of current through the diodes around the set of contacts to the load interface.

Abstract: A combiner circuit and voltage protection circuit is disclosed. A plurality of photovoltaic sources is provided. A set of fuses, each having one side coupled to one of the plurality of photovoltaic sources is provided. A set of contacts, each having one side coupled to the other side of one of the fuses is provided. The other side of the contacts are coupled together to combine the output of the photovoltaic sources to an output interface, the output interface being coupled to the load. A set of diodes are each coupled to each of the set of fuses and form a current path around the set of contacts. A transistor is coupled to each of the diodes and the load interface. The transistor has an on state completing the flow of current through the diodes around the set of contacts to the load interface.

Abstract: The invention is a device and method for eliminating core excitation losses in a distribution transformer when the transformer is not supplying power to loads. The invention consists of sensors, a control circuit, a user interface and a power contactor. The power contactor is connected on the line side of a transformer and is opened or closed automatically based on preprogrammed time or load criteria determined by the control circuit. In one operational mode and when the transformer is disconnected from the line, the control board generates low power pulses at the transformer load connection points in order to “search” for loads. If a load is detected, the transformer is reconnected by way of contactor closure. If the transformer load drops to zero, for a predetermined amount of time, the transformer is again disconnected and the pulsed load search is reestablished.

Abstract: An electronic business and information card device having sound recording means and sound producing means operably connected to sound storing means, all disposed within a business-card sized housing. The device is battery powered and features three-button operation. Sound information may be pre-recorded. The device has a lockout means to prevent inadvertent erasure of pre-recorded information and to selectively permit recording of new sound information over previous sound information. The surfaces of the housing are provided with identifying information such as names, logos and contact information. Alternatively, the surfaces of the housing may be left blank for customization by intermediate- or end-users.

Abstract: The invention is a device and method for eliminating core excitation losses in a distribution transformer when the transformer is not supplying power to loads. The invention consists of sensors, a control circuit, a user interface and a power contactor. The power contactor is connected on the line side of a transformer and is opened or closed automatically based on preprogrammed time or load criteria determined by the control circuit. In one operational mode and when the transformer is disconnected from the line, the control board generates low power pulses at the transformer load connection points in order to “search” for loads. If a load is detected, the transformer is reconnected by way of contactor closure. If the transformer load drops to zero, for a predetermined amount of time, the transformer is again disconnected and the pulsed load search is reestablished.

Abstract: An electrical DC-to-AC power conversion apparatus is disclosed that is primarily intended for use with solar photovoltaic sources in electric utility grid-interactive applications. The invention improves the conversion efficiency and lowers the cost of DC-to-AC inverters. The enabling technology is a novel inverter circuit topology, where the bulk of the throughput power, from DC source to AC utility, is processed only once. The inverter does not require an isolation transformer and can be connected directly to a 480/277 Vac utility grid. The invention also allows the power converter to start into photovoltaic array having higher open circuit voltages. The invention also uses active ripple current cancellation to substantially reduce the cost, size and weight of the main filter inductors.

Abstract: An electronic business and information card device having sound recording means and sound producing means operably connected to sound storing means, all disposed within a business-card sized housing. The device is battery powered and features three-button operation. Sound information may be pre-recorded. The device has a lockout means to prevent inadvertent erasure of pre-recorded information and to selectively permit recording of new sound information over previous sound information. The surfaces of the housing are provided with identifying information such as names, logos and contact information. Alternatively, the surfaces of the housing may be left blank for customization by intermediate- or end-users.

Abstract: The invention is a device and method for eliminating core excitation losses in a distribution transformer when the transformer is not supplying power to loads. The invention consists of sensors, a control circuit, a user interface and a power contactor. The power contactor is connected on the line side of a transformer and is opened or closed automatically based on preprogrammed time or load criteria determined by the control circuit. In one operational mode and when the transformer is disconnected from the line, the control board generates low power pulses at the transformer load connection points in order to “search” for loads. If a load is detected, the transformer is reconnected by way of contactor closure. If the transformer load drops to zero, for a predetermined amount of time, the transformer is again disconnected and the pulsed load search is reestablished.

Abstract: 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.

Abstract: An electrical DC-to-AC power conversion apparatus is disclosed that is primarily intended for use with solar photovoltaic sources in electric utility grid-interactive applications. The invention improves the conversion efficiency and lowers the cost of DC-to-AC inverters. The enabling technology is a novel inverter circuit topology, where throughput power, from DC source to AC utility, is processed a maximum of 1½ times instead of 2 times as in prior-art inverters. The AC inverter output configuration can be either single-phase, split-phase or poly-phase.

Abstract: 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.

Abstract: An electrical DC-to-AC power conversion apparatus is disclosed that is primarily intended for use with solar photovoltaic sources in electric utility grid-interactive applications. The invention improves the conversion efficiency and lowers the cost of DC-to-AC inverters. The enabling technology is a novel inverter circuit topology, where throughput power, from DC source to AC utility, is processed a maximum of 1½ times instead of 2 times as in prior-art inverters. The AC inverter output configuration can be either single-phase, split-phase or poly-phase.

Abstract: 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.

Abstract: An electrical DC-to-AC power conversion apparatus is disclosed that is primarily intended for use with solar photovoltaic sources in electric utility grid-interactive applications. The invention improves the conversion efficiency and lowers the cost of DC-to-AC inverters. The enabling technology is a novel inverter circuit topology, where the bulk of the throughput power, from DC source to AC utility, is processed only once. The inverter does not require an isolation transformer and can be connected directly to a 480/277 Vac utility grid. The invention also allows the power converter to start into photovoltaic array having higher open circuit voltages. The invention also uses active ripple current cancellation to substantially reduce the cost, size and weight of the main filter inductors.

Abstract: The invention is a method and apparatus for supplying both positive and negative gate drive power supply potentials to the top switch, in a typical half-bridge semiconductor power topology, from the bottom switch gate drive power supplies and without the use of transformer, capacitive or optical isolation. A known method of providing the positive top switch gate drive supply is enhanced and used in conjunction with a new and novel method for providing the negative top switch gate drive supply. The negative top switch gate drive supply is provided by an additional, lower power semiconductor switch, which is substantially synchronized with the bottom semiconductor switch, except for a slight turn-on delay. When this additional switch is gated “on” and conducting, the negative bottom switch gate drive power is connected to the negative top switch gate drive supply energy storage capacitors.

Abstract: 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.

Abstract: This invention is a multi-port power converter where all ports are coupled through different windings of a high frequency transformer. Two or more, and typically all, ports have synchronized switching elements to allow the use of a high frequency transformer. This concept and type of converter is known. This invention mitigates a number of limitations in the present art and adds new capabilities that will allow applications to be served that would otherwise not have been practical. A novel circuit topology for a four-quadrant AC port is disclosed. A novel circuit topology for a unidirectional DC port with voltage boost capabilities is disclosed. A novel circuit topology for a unidirectional DC port with voltage buck capabilities is disclosed. A novel circuit for a high efficiency, high frequency, bi-directional, AC semiconductor switch is also disclosed.

Abstract: The invention is an electromechanical packaging method for high power, high reliability, high frequency, switch mode power converters where high power density is required. An Insulated Metal Substrate (IMS) Printed Circuit Board (PCB) assembly, with a plurality of surface mount semiconductor power devices, is interfaced to a heatsink. Low profile bus bars are used between the IMS PCB and a fiberglass PCB. The fiberglass PCB has a laminated DC bus structure and a plurality of filter capacitors electrically connected across the DC bus structure. Clamp bars, substantially following the footprint of the bus bars, are installed on top of the fiberglass PCB and are used to pull the heatsink-IMS-bus bar-fiberglass PCB-clamp bar sandwich together. The clamping action provides low contact resistance between the bus bars and the two printed circuit boards. The clamping action also supplies the pressure needed between the IMS substrate and the heatsink for good heat transfer across this interface.