Showing papers on "Electrical network published in 2000"

SPICE model of thermoelectric elements including thermal effects

Abstract: An electrical model for a Peltier cell, based on the analogy between thermal and electrical variables, is proposed. The use of thermal models allows the global performance of thermocooling circuit and signal system to be checked by using electrical circuit analysis programs such as SPICE. The maximum error in the steady state between measured and simulated temperatures are less than 0.3/spl deg/C for hot temperature and less than 0.2/spl deg/C for cold temperature with 31.7/spl deg/C of temperature change.

Energy flow and power phenomena in electrical circuits: illusions and reality

Abstract: Common opinions respective to the nature of the reactive power, energy flow and oscillations, as well as the notion of the apparent power in single- and in three-phase systems are discussed in this paper. It is shown that some interpretations of powers and energy flow in linear, single-phase circuits are often generalized for more complex situations where these interpretations are not longer valid. Consequently, power phenomena in electrical systems are often misinterpreted. This relates to the reactive power which occurs in three-phase systems without energy oscillation between the supply source and the load, as well as it occurs in time-variant systems without energy storage capability. Also, it was demonstrated in the paper that the arithmetic and geometric apparent powers, commonly used in three-phase systems, do not characterize the supply loading correctly when the load is unbalanced.

Electrical power extraction from mechanical disturbances

Abstract: A method of extracting power includes coupling a transducer that converts mechanical power to electrical power to a disturbance; coupling an electrical circuit to the transducer such that a peak voltage experienced by the transducer is greater than two times higher than any peak voltage of an open circuit transducer due to the disturbance alone; extracting power from the transducer using the electrical circuit, and storing extracted power. Power is extracted from the transducer and applied to the transducer during different intervals in the course of the disturbance. A system for extracting power includes a transducer, an electrical circuit, and a storage element for storing extracted power.

Arc fault circuit interrupter

Abstract: A system for producing a simulated ground fault when arcing is present in an electrical circuit includes a sensor which monitors the electrical circuit. An arcing fault detection circuit determines whether an arcing fault is present in response to the sensor and produces a trip signal in response to a determination that an arcing fault is present in the electrical circuit. A ground fault simulator circuit produces a simulated ground fault in response to the trip signal.

Control method comparison of doubly fed wind generators connected to the grid by asymmetric transmission lines

Abstract: A speed controller operating on a doubly-fed induction generator can be improved to compensate asymmetries on voltage waveforms feeding the machine's stator. This is particularly interesting for variable-speed wind power generators connected to an electrical network through weak transmission lines. Any asymmetry on the line causes the currents to be unbalanced, which will distort voltage waveforms at the beginning of the line, degrade the power quality injected into the network, lower the efficiency of energy transmission and increase the thermal losses in the generator. This paper presents the performance of three different compensation procedures based on the control of the waveform of a doubly fed generator's output current. A brief description of the model of the wind power system developed using reference frame theory is first introduced, followed by the description of the three different control techniques proposed to maintain balanced currents: a linear proportional and integral (PI) controller, a nonlinear fuzzy controller and a mixed scheme consisting of a fuzzy control adjusting PI parameters online. The performance of the three methods are then compared in terms of their efficiency in controlling the speed and compensating asymmetries. Simulations show that current asymmetries can be greatly decreased, by waveform control without sacrificing speed regulation.

DC-DC converter with current sensing for use with non-linear devices

Abstract: Provided is an electrical circuit that provides a boosting circuit that all in one provides a regulated step-up voltage to a non-linear device such as an array of light emitting diodes (LEDs) used in a liquid crystal display (LCD). The unique placement of the current sensing circuit within the boosting circuitry eliminates the need for a separate current regulating circuit, thus minimizing the circuitry needed to provide a constant back lighting LED array of constant luminosity.

Envelope following method for the transient analysis of electrical circuits

Abstract: An envelope following method (EFM) that allows efficient transient simulations of electrical circuits is here presented. Its mathematical and electrical bases are considered and the influence of some general properties, such as stability and truncation error of integration methods employed by EFM, are studied. Furthermore, we present a new state variable prediction algorithm that improves previously reported ones, since it better adapts to fast dynamics of the solution. A set of power switching circuits is employed as a benchmark and numerical results of our algorithm are compared to those of conventional integration and of previous EFM versions. Remarkable results are obtained in the electrothermal simulation of power converters where the efficiency gain rises up to some magnitude orders with respect to conventional integration.

Method and apparatus for obtaining a precision thickness in semiconductor and other wafers

Abstract: A method and apparatus for processing a wafer comprising a material selected from an electrical semiconducting material and an electrical insulating material. The wafer has opposed generally planar front and rear sides and a peripheral edge, wherein said wafer is pressed against a pad in the presence of a slurry to reduce its thickness. The thickness of the wafer is controlled by first forming a recess such as a dimple on the rear side of the wafer. A first electrical conducting strip extends from a first electrical connection means to the base surface of the recess to the second electrical connector. The first electrical conducting strip overlies the base surface of the recess. There is also a second electrical conductor with an electrical potential source between the first electrical connector and the second electrical connector to form. In combination with the first electrical conducting strip, the second electrical conductor forms a closed electrical circuit, and an electrical current flows through the closed electrical circuit. From the front side of the wafer the initial thickness of the wafer is reduced by lapping until the base surface of the recess is reached. The conductive strip is at least partially removed from the base surface to automatically stop the lapping procedure and thereby achieve the desired thickness.

Dynamic analysis of a variable speed wind turbine equipped with a voltage source AC/DC/AC converter interface and a reactive current control loop

Abstract: In this paper the analysis of the dynamic behavior of a variable speed wind turbine (VSWT) is presented. Comparison between variable speed and constant speed (CS) mode of operation is also performed. The examined wind turbine is equipped with a dual PWM voltage source converter cascade and connected to an electrical network represented by the Thevenin equivalent. Conventional scalar control is applied to the electrical generator, employing the constant V/f principle. Furthermore, the grid side inverter is assumed capable of regulating its output reactive power in order to maintain the voltage within permissible variations. The objective is to point out some of the advantages of the variable speed (VS) operation, such as the improved output power quality, the decrease of the mechanical stresses and the capability of controlling the voltage of the local grid.

Method for the distribution of information

Abstract: To be able to transmit information at high bit rate in a domestic or industrial installation, it is planned to receive information at high bit rate sent by a remote sender unit to a specialized receiver. This specialized receiver playing the role of a network master is then provided with means to transmit this information by a carrier current channel made on the electrical network of the installation. In reception, a coupler is used to pick up this information from the electrical network. It is shown that, by acting in this way, it is possible to remove the need to make a specific infrastructure for this transmission at high bit rate, and that it is thus possible to enjoy the facility of having tapping points at all places since an electrical power supply network is generally distributed extensively in a building. Furthermore, several characteristics of modulation and transmission are chosen to withstand parasites and defects of transmission inherent in this type of network. It is shown, especially, that the characteristics chosen for this occasion may also be used in a different context. In particular, it is planned that a time equalization of the channel, which is costly, is not done systematically in a sender unit and a receiver but only in one or the other, and that, furthermore, this channel time equalization can concern only certain frequencies of a total spectrum sent, namely those frequencies for which the signal-to-noise ratio is good whereas, for the others, the efficiency of the equalizer is lower.

An electrical coil module, an electrical coil comprising such modules, an actuation mechanism including such a coil and a circuit breaker comprising such an actuation mechanism

Abstract: An electrical coil module of planar type referably manufactured by means of printed circuit techniques on a generally flat substrate (21) has a first layout (20) of conducting material constituting a first electrical conductor having an input terminal (23), arranged on one side of said substrate (21). A second layout (20') of conducting material constituting a second electrical conductor having an output terminal (24), is arranged on the opposite side of said substrate. The first and second conductors are connected by means of an electrical connection (22) through the substrate (21), so that an electrical voltage connected between the input and output terminals of the coil module will drive a current from one terminal through the conductor on one side of the substrate via connection (22) through the substrate and the conductor on the other side of the substrate to the other terminal. An electrical coil comprising such modules is also described as well as an actuation mechanism including such a coil and an electrical circuit breaker comprising such an actuation mechanism.

Multi-axis connectors and electronic devices incorporating same

Abstract: Multi-axis electrical connectors for use within electronic devices such as radiotelephones are provided that may reduce the risk of electrical circuit breaks caused by impacts and/or vibrations Multi-axis electrical connectors are configured to electrically communicate with electronic modules via multi-axis electrical interfaces Electrical contact between a first set of contacts and an electrical interface along a direction can be maintained when a force is applied along a transverse direction Conversely, electrical contact between a second set of contacts and another portion of the electrical interface along another direction can be maintained when a force is applied along a transverse direction

Modeling and dynamic regulation of a wind farm

Abstract: Electrical systems endowed with variable generating units will dominate the electrical landscape in the near future. These types of generating units will bring new opportunities to utilities, companies and customers, but they will also bring new problems to electrical companies. As wind power generation is one of the most important sources, because its production is environmentally clean, it is important to achieve proper locations for new wind farms. So, to evaluate their impact on the electrical network it is necessary to develop an accurate wind farm model for the network analysis program. This paper presents the modeling and control of a wind farm exclusively made up of doubly fed induction machines.

High-pass filter

Abstract: The invention relates to an electric filter for filtering low frequencies in order to protect an electronic circuit from ESD. A high-pass filter (1) for filtering low frequencies is used in the signal path between an antenna connector (2) and an electrical circuit (3) in a communication unit. Via the antenna connector different antennas may be connected. The high-pass filter (1) for filtering low frequencies is erected with a capacitance (C1) in the serial path and an inductance (L1) in the parallel path. The high-pass filter (1) allows the protection of the following electrical circuit (3). As a further aspect the high-pass filter has a cutoff frequency lower than the lowest cutoff frequency of a radio frequency separator in the electrical circuit (3).

Power law fluctuation generator based on analog electrical circuit

Abstract: We constructed an analog circuit generating fluctuations of which a probability density function has power law tails. In the circuit, fluctuations with an arbitrary exponent of the power law can be obtained by tuning the resistance. A theory of a differential equation with both multiplicative and additive noises which describes the circuit is introduced. The circuit is composed of a noise generator, an analog multiplier and an integration circuit. Sequential outputs of the circuit are observed and their probability density function and autocorrelation coefficients are shown. It is found that correlation time of the autocorrelation coefficient is dependent on the power law exponent.

Automobile onboard electrical network has self-holding undervoltage relay for switching safety relevant electrical loads across from onboard network battery to emergency battery

Abstract: The onboard electrical network (1) has at least one onboard network battery (2) and an emergency battery (8) used for emergency supply of safety relevant electrical loads (10-14) upon uncoupling from the normal supply network, via a self-holding undervoltage relay (5). A diode (7) can be coupled between the onboard network battery and the emergency battery.

A fluorescent lamp model for high-frequency electronic ballasts

Abstract: An electrical circuit model of the fluorescent lamp for high-frequency operation is presented. The circuit model is represented by a power and temperature dependent resistance. A test system is set up to obtain the lamp arc voltage equation for a given lamp from few test data, and then the arc current and the equivalent resistance can be derived. By these lamp equations, the electrical behavior of the lamp can be described. The circuit model can be used for predicting the operating characteristics of the dimmable electronic ballast-lamp circuits with considerations on the effects of the operating power and temperature. The verification of the proposed lamp model is illustrated by implementation examples.

Effects of supply voltage non-idealities on the behavior of an active power conditioner for cogeneration systems

Abstract: The use of a power conditioning system (PCS) connecting a cogeneration plant to the electrical network, makes it possible to employ high-speed turbines directly coupled to permanent magnet synchronous generators. This solution leads to a very compact arrangement, characterized by high reliability and efficiency. Furthermore, the PCS is able to deliver not only the rated active power to the mains, but reactive power and current harmonics as well. In this way, the PCS can operate as active filter when nonlinear loads are connected to the same network. Nevertheless, undesired behavior may occur when the supply voltages are nonideal, such as in presence of unbalance, harmonics, flicker, or when the line impedance is not negligible. This paper presents a new control strategy that allows good performance to be achieved under ideal and nonideal supply voltages. The stability and the dynamic behavior of the overall system has been analyzed by introducing suitable transfer functions. The analytical developments have been confirmed by performing numerical simulations an a realistic circuit model implemented with PSpice.

Electric power system state estimation : The technology of power system competition

Abstract: This paper discusses the state of the art in electric power system state estimation. Within energy management systems, state estimation is a key function for building a network real-time model. A real-time model is a quasi-static mathematical representation of the current conditions in an interconnected power network. This model is extracted at intervals from snapshots of real-time measurements (both analog and status). The new modeling needs associated with the introduction of new control devices and the changes induced by emerging energy markets are making state estimation and its related functions more important than ever.

Combination circuit board and segmented conductive bus substrate

Abstract: A combination circuit board ( 12 ) and segmented bus structure ( 54 ) defines a composite circuit board/bus assembly ( 52 ) upon which an electrical circuit may be assembled. The various segments ( 54 a -54 f ) of bus structure ( 54 ) may be variously configured to achieve one or more assembly, performance, testing, and/or reliability goals. For example, one bus segment configuration provides integral connector tabs ( 54 a and 54 e ) for mechanical and/or electrical connection to interconnecting wires or electrical terminals of one or more external devices. Another bus segment configuration ( 54 d ) provides for mechanical and high current electrical interconnections between one or more bus segments ( 54 a -54 f ) and one or more electrical components ( 16, 18, 20 ) and/or conductive film patterns( 64 ) formed on top surface ( 12 b ) of the circuit board ( 12 ). Still another bus segment configuration provides integral tabs ( 54 b and 54 c ) for electrical connection to and mechanical attachment of electrical components ( 16, 18, 20 ) from one or more of such tabs ( 54 b and 54 c ) extending through the circuit board ( 12 ) to other such tabs ( 54 b and 54 c ) or other circuit structures. Yet another bus structure ( 54 f ) provides for highly efficient heat sinking capability and/or electrical connection for electrical components ( 18 ) mounted either directly to one or more bus segments ( 54 f ) and for electrical components ( 18 ) mounted to a substrate ( 68 ) that is itself mounted directly to one or more bus segments ( 54 f ).

Method of reactive power regulation and aparatus for producing electrical energy in an electrical network

Abstract: A method of reactive power regulation in an electrical network in which electrical power is produced by an electrical generator preferably driven by the rotor of a wind power installation and suitably modulated by means of a compensation device between the generator and the network for the compensation of reactive power, and an apparatus for producing electrical energy in an electrical network, preferably an electrical generator driven by the rotor of a wind power installation and a compensation device between the generator and the network for the compensation of reactive power. The compensation device is so regulated that the electrical power delivered to the consumer has a reactive power component which is adapted in respect of its phase, amplitude and/or frequency to the consumer in such a way as to compensate for the reactive power in the consumer.

FEM solution of time-harmonic electromagnetic fields by an equivalent electrical network

Abstract: A new circuit-oriented, full-wave method is presented to analyze electromagnetic fields by an equivalent electrical network. By the FEM the vector wave equation problem is transformed in an algebraical system, which is solved by equivalent circuits. In the paper the original method is theoretically formulated and is applied in test configurations, where a comparison is made with the classical FEM solution.

Structure for decorative lighting string

Abstract: The present invention is related to a kind of decorative lighting string structure comprising multiple lamp bulbs, multiple lamp bases or lamp holders and multiple electrical conductors, receptacles, flasher control and non-electrical connector, being connected in series, parallel or series and parallel to form a complete electrical circuit, said non-electrical connector and the electrical conductor of electrical circuit to be wound into twister, said bulb or lamp base or lamp holder being trapped into a proper place of twister formed between electrical conductor or non-electrical connector and fixed in the connecting place of lamp base and electrical conductor, said bulb and lamp base or lamp holder to be limited to a proper interval to combine into regular or irregular patterns of triangular, rhombic, rectangular or square units, said units being connected and arranged into a certain appearance, design or words and to obtain a decorative effect.

Automobile onboard electrical network system has power diode and series switch element across DC/DC converter between electrical supply network and partial network containing safety relevant loads

Abstract: The electrical network system has an electrical supply network and at least one partial network containing safety relevant electrical loads, both networks operated at the same voltage level with a DC/DC converter (23) between them. The DC/DC converter is bridged by a power diode (21) in series with a switch element (22), with at least one further switch element (24,25) in series with the parallel circuit. An Independent claim for a monitoring method for an onboard electrical network system is also included.

Quantum control techniques for switched electrical networks

Abstract: We illustrate two techniques for specifying piecewise constant controls for a switched electrical network used in converting power in a DC-DC converter. Both procedures make use of decompositions of SU(2) to obtain controls that satisfy pulse area constraints. One of the methods depends intrinsically on the network and we show that ideal controls can be obtained with this technique. The other approach is general, but requires more computational effort. The systems being studied are single input systems with drift. In this paper no approximations or other artifices are used to remove the drift. Instead, the drift is important in the determination of the controls. Piecewise content controls, such as the ones obtained in this work, are closer to physical reality than other types of controls. We also show how to obtain controls with values of either 0 or 1 which represent the position of the switch.

Adaptive tolerance reference inspection system

Abstract: Method and apparatus for automatically optically inspecting electrical circuits by matching portions of an electrical circuit being inspected to corresponding portions in a reference, wherein an adaptive spatial tolerance representing a permissible deviation in the location of corresponding portions is applied to a portion. The spatial tolerances for each portion is in part a function of a characteristic of the portion, for example one or more of: the proximity of the portion to other portions of predetermined type, a spatial location of the portion in an electrical circuit, a material from which the portion is formed, the color of the portion and the intensity of light reflected by the portion. Non-defective matching portions an electrical circuit being inspected and in a reference must be separated by a distance which is less than the adaptive spatial tolerance.

Electrical circuit with a testing device for testing the quality of electronic connections in the electrical circuit

Abstract: Given the inventive electrical circuit with a device for testing connections in electrical circuits, the change of a test signal (27) due to the effect of a long line is used for determining the quality of an electrical connection (e.g., of a pin). In particular, a determination about the terminating impedance and, thus, about the quality of the connection, is made by defining a maximum value of the test signal (28) reflected at the line end. An existing boundary scan test implementation with appropriate expansions can thereby be used, including a test controller. Standard digital signals can be employed as test signal when their propagation time is lengthened by a delay element.