Showing papers on "Maximum power transfer theorem published in 1984"

Tuning arrangement for interfacing credit card-like device to a reader system

Abstract: A circuit for maximizing power transfer from a station to an interactive memory card via a capacitive interface. A reader system in the station generates an ac signal which provides operating power that is transferred to the card through the capacitive interface formed when the card is placed against a window on the station. The ac signal from the station is directed through a series resonant circuit to the card. The capacitive interface between the station and card make up the capacitive element of the resonance circuit while the series combination of the secondary of a transformer and an electrically variable inductor form the inductive element. Use of the variable inductor allows the station to tune the circuit to resonance and cancel the capacitive element, thereby maintaining maximum power transfer to the card.

Contactless power transfer--An exercise in topology

Abstract: Previous attempts at different forms of contactless power transfer systems associated mainly with high speed ground transportation and magnetic levitation are reviewed. Two different types of contactless power transfer systems are proposed as replacements for the brush-and-conductor, trailing cable, or reeling drum, where these options were inappropriate or would suffer excessive wear or other degradation in the stringent applications encountered in the nuclear or mining industries. The first system uses busbars as longitudinal members along which an output transformer can move. The second system uses magnetic material as the longitudinal members, can be formed into a robust composite structure, and can be arranged to provide a surface wiping geometry for the moving output core: this system is essentially the magnetic dual of a conductor rall and contacting brushgear. Examination of the systems' topologies allows longitudinal, curved or circular systems to be developed, and non-nuclear applications which include, for example, contactless power transfer for robotic Joints are envisaged.

Power transfer of direct current with inductive couplings

Abstract: A source of DC electrical power (A) provides DC electrical power to a power transmission cable (B) which extends to a remote location, such as a subsea module (D). The power transmission cable is connected with a pair of rectifiers (20a, 20b), each allowing only power of a selected polarity to be passed thereby. A pair of DC to AC inverters (24a, 24b) convert the received electrical power to high frequency square waves which are applied across primary windings (32a, 32b) of inductive couplers (30a, 30b). Secondary windings (38a, 38b) of the inductive couplers convey the AC electrical power to remote module rectifiers (40a, 40a) for providing DC electrical power to the subsea module. In this manner, DC electrical power is transmitted along the power transmission cable to reduce interference and crosstalk, yet the electric power is transmitted across an inductive coupler to facilitate safe separation of the remote module from the power transmission cable.

Transformer utilizing selectively loaded reactance to control power transfer

Abstract: Apparatus for controlling power transfer in an electrical induction device uses a controlled reactance to regulate the power transferred from an alternating current power source to a load without distorting or degrading the transferred power waveshape. The apparatus includes a power transformer having a power core and a primary coil and a secondary coil each encircling the power core. A number of control cores, separate from the power core, have associated control coils which are selectively short-circuited to provide the controlled reactance. The primary coil is arranged to encircle the control cores and coils and the secondary coil so that the primary coil is subject to the controlled reactance of the control cores.

DC to AC series-resonant converter system with high internal frequency generating synthesized waveforms for multikilowatt power levels

Abstract: A new method of power pulse modulation with internal frequencies of tens of kHz and suited for multikilowatt power levels is applied to a series-resonant converter system for generating synthesized unipolar and bipolar waveforms. The high pulse frequency allows the principle of modulation and demodulation to be applied for fast system response, output waveforms with low distortion and prevents excessive stresses on components. Natural current commutation of the thyristors is obtained by the use of a series-resonant circuit for power transfer and control. Test results of a 4 kW thyristor converter system generating sinusoidal and non-sinusoidal waveforms independently of the load characteristics demonstrate the significane aspects for this class of power conversion. The material presented indicates the capability of the system to avoid excessive component stresses as well as the possibilities for fast acting four-quadrant dc to dc, single-phase or polyphase dc to ac and ac to ac converter systems.

Impedance matching in radio-frequency discharge excited waveguide lasers

Abstract: The problem of matching the impedance of a radio-frequency power generator to a gas laser discharge tube is analysed in terms of the 'split inductance' matching network Representing the laser structure and discharge by an electrical equivalent circuit, expressions are derived for the fractional power transfer to the discharge and the voltage gain provided by the matching circuit in terms of the generator frequency and discharge conditions In addition, the design criteria are discussed for the selection of the coil inductances and laser head characteristics for optimum power transfer

High voltage-high power components for large space power distribution systems

Abstract: Space power components including a family of bipolar power switching transistors, fast switching power diodes, heat pipe cooled high frequency transformers and inductors, high frequency conduction cooled transformers, high power-high frequency capacitors, remote power controllers and rotary power transfer devices were developed. Many of these components such as the power switching transistors, power diodes and the high frequency capacitor are commercially available. All the other components were developed to the prototype level. The dc/dc series resonant converters were built to the 25 kW level.

Measuring apparatus of power transfer loss of gear box

Abstract: PURPOSE:To enable the accurate measurement of a power transfer loss in a short time, by providing a loss computing circuit which computes said transfer loss from a detection value of the state of each section of a gear box and prescribed correlation data CONSTITUTION:A gear box power transfer loss computing circuit 62 is supplied with a detected value 106 of a rotation speed, a detected value 110 of an oil quantity, detected values 112, 114 and 116 of oil temperatures and a detected value 118 of temperature from a group of detectors detecting the state values of the sections of a gear box 22 respectively, namely a pickup 34, an oil-quantity detector 36, and temperature detectors 38, 40, 42 and 44, and further it is supplied with a detected torque value 120 from a load cell 30 In the computing circuit 62, a power transfer loss of the gear box 22 is computed accurately from said output values and the correlation data of the state value of each section of the gear box 22 indicated beforehand and the powe transfer loss Thus, the power transfer loss can be measured accurately in a short time

Maximum power transfer in non‐linear source‐load systems

Abstract: This paper is concerned with the conceptual design and realization of matching networks for the continuous transfer of maximum power from a non-linear source with randomly varying characteristics to a load. Such sources are commonly encountered in the use of photovoltaic arrays or wind energy conversion systems for the production of electric power. Experimental studies as well as computer simulation results verify the validity of the design and point to methods for its practical implementation.

The Use Of Power Transfer Matrices In Predicting System Loss: Theory And Experiment

Abstract: The phase space diagram for parabolic and step index fibers leads to a graphic representation of the bound, leaky, and refracted rays of ray theory. This concept is used to predict the attenuation of typical components of local area networks. The technique uses power transfer matrices to track the evolution of power distribution in ray packets. In particular, we predict and then measure the power transfer of two ray packets for a step index fiber. The comparison is encouraging.

Design of a Power Conditioning Unit for Nonlinear Source-Load Systems

Abstract: This paper describes the development, design, and operation of an electronic device which performs dynamic matching between electric energy sources and their respective loads. This matching is achieved by monitoring the output power of the energy source and modulating a control signal which, in turn, regulates appropriately the operation of a source-load interface device. This device is characterized by a simple structure and an ability to continuously match the characteristics of the source to those of the load, for maximum power transfer, even when these characteristics are randomly time-varying. The device may be used with existing energy systems, without significant changes, and operates effectively even when the utility grid substitutes for the load. Its operation is described in terms of a configuration involving renewable energy sources, such as wind electric conversion systems and photovoltaic arrays, as the primary energy generators. The latter are attracting the growing interest of many investigators recently.