Showing papers on "Power module published in 1976"

Three-Phase AC Power Control Using Power Transistors

Abstract: A three-phase ac power control circuit using power transistors which operate in a high-frequency chopping mode is described. The circuit is capable of handling several kilowatts of power at any lagging load power factor angle and the output voltage can be smoothly controlled from zero to full supply voltage. The circuit has inherently fast response and the high-frequency ripple at the output is easily filtered. The development, study, and experimental evaluation of the circuit with resistive and induction motor loads is described.

Portable data-gathering apparatus formed by modular components having operate-standby modes

Abstract: A hand-held data-gathering unit is formed by removably connected control and power modules: The control module contains a keyboard, a display device, a data input probe, and a microprocessor. The power module contains a rechargeable battery with a converter and associated power logic, and a memory system with associated memory control logic. The hand-held unit has a normal low-power standby mode which is maintained during the absence of input data from either the keyboard or the data probe, and an operation mode which is initiated by the arrival of input data. During the operation mode, input data enters the control module and is forwarded to the memory in the power module. As data is gathered during portable operation, the memory may reach capacity or the battery voltage may drop, or both. The power module may be removed from the control module and replaced by a fresh power module with a fully charged battery and an empty memory. The expired power module is inserted into a service module for charging the battery or transmitting the data to a remote terminal, or both. The control module may also be inserted into the sevice module where it is activated by a stationary power supply and interfaced with the memory in the power module for stationary operation. In addition to transmitting the contents of the memory, the service module may receive data from the remote terminal and for storage in the memory. This received data may then be accessed and displayed through the control module.

Aircraft electrical systems

Abstract: Preface 1. Direct Current Power Supplies 2. Alternating Current Power Supplies 3. Power Conversion Equipment 4. External and Auxiliary Power supplies 5. Power Distribution 6. Circuit Controlling Devices 7. Circuit Protection Devices and Systems 8. Measuring Instruments and Warning Indication Systems 9. Power Utilization - Motors 10. Power Utilization - Systems 11. Electrical Diagrams and Identification Schemes Appendices 1. Electrical and Magnetic Quantities, Definitions and Units 2. Ohm's Law 3. Power in A.C. Circuits 4. Connection of Capacitors and Inductors 5. Fundamental A.C. Circuits and Formulae 6. Conversion Factors 7. Power Generation System Applications 8. Electrical Diagram Symbols 9. Representative Aircraft Ice and Rain Protection Systems 10. Abbreviations and Acronyms associated with Electrical Systems. 11. Logic Gates and Truth Tables Exercises Solutions to Exercises Index

Plug in regulating power supply

Abstract: A plug in power supply incorporating a ferro resonant transformer mounted on a pair of opposite "E" laminations to provide a low profile magnetic circuit and windings thereon combined with an electronic voltage regulator in which the regulation required therefrom because of the transformer regulation is relatively low and the electronic power component thereof will therefore not be required to dissipate a large amount of power. This enables packaging in a sealed container with a heat sink mounting the power transistor to uniformly distribute the heat thereon and provide a safe plug in power supply.

Low-power monolithic COS/MOS dual-slope 11-bit A/D converter

Abstract: A single-chip, auto-zeroing, dual-polarity, single power supply A/D converter will be discussed, citing CMOS amplifier techniques used and performance results.

Measurements of power transistor thermal instabilities, stable hot-spots, and second-breakdown

Abstract: The relationships of thermal instability, stable hot spots, and second breakdown in power transistors are discussed. A rationale is also given for using thermal instability as opposed to second breakdown as the specified limit of safe operation for power transistors. It is shown that the limit of thermal instability can be accurately predicted and the simple device measurements required to do this are described. A rapid, easy, nondestructive test is also described for experimentally determining this limit.

Waste energy source utilization circuit and method

Abstract: A switching circuit, typically a thyristor bridge, is connected to a source of waste energy. The source can be waste energy occurring as a by-product of man's activities such as waste heat energy, stored water, or the potential mechanical energy of elevated objects. The source provides d.c. power either directly or through conversion. The switching circuit is also connected to an a.c. load and across a.c. power mains energizing the load. The switching circuit is operable to periodically connect the waste energy source to the a.c. load in a power supplying manner. The a.c. mains impart suitable voltage and frequency characteristics to the electrical power so supplied. In the event the supplied power exceeds the power required by the a.c. load, the difference is taken by the a.c. power mains.

Review of the technology for wave power conversion

Abstract: Presented is a review of the technology of wave power conversion. Hundreds of patents have been issued on wave power conversion; these include propulsion schemes, buoy power supply devices, offshore power plants and shore-based power stations. Energy densification is a requirement before conversion, and schemes used for it have been resonance, accumulation with time and wave height amplification by converging channels or refraction. Variability of the mean power with time, presence of tide and the possibility of occasional onslaught by very high waves pose challenging problems.

Short circuit protected electronic control system

Abstract: To protect power transistors and similar electronic electronic control elements which have their main current paths serially connected to loads, one terminal of which is grounded, against short circuits within the loads and without substantial power loss in series sensing resistors, a resistor is connected in shunt with the main current path of the power electronic component, for example the emitter-collector path of a power resistor and a diode connected between this shunt-connected resistor, effectively at the junction of the load and the power semiconductor to the base of a driver transistor which controls the power semiconductor to apply the operating voltage at the junction to the base of the driver transistor so that the power transistor is controlled thereby to blocked condition if the voltage at the junction should drop from operating voltage, the diode, under normal operating condition, being blocked.

Power factor of active filtering systems

Abstract: Solid state power conditioners have historically presented poor power factors to single phase supplies. An analysis technique is presented, while several typical input currents are discussed and waveform bounds presented which allow high (0.9) power factors.

Inverters for commercial fuel cell power generation

Abstract: This paper describes the results of work accomplished in developing low cost, high efficiency dc to ac power conversion equipment for fuel cell powerplants to be used in two different commercial applications. The first is for on-site power generation in the range of 10 to 500 kW and the second is for dispersed electric utility power generation in substations at a 26 MW power level. Performance data is presented on single-phase and three-phase prototype inverters in the first category. Work currently in progress on the 26 MW inverter is described including operational tests on a 500 kW unit delivering power into the lines of the Connecticut Light and Power Company. To accomplish the desired results, fast switching thyristors with low forward drop and high dv/dt are used.

Apparatus for regulating the voltage of an electric source

Abstract: 1447527 Automatic voltage regulation ATELIERS DE CONSTRUCTIONS ELECTRIQUES DE CHARLEROI 19 Oct 1973 [20 Oct 1972 19 March 1973(2)] 48935/73 Heading G3R A power source comprises a number of cells producing current from incident radiation and grouped into modules which are connected in parallel to a common distribution conductor. The conductor voltage is regulated by comparison with a reference to form an error signal which can effect coarse regulation by connecting or disconnecting one of the modules, or fine regulation by actuating a circuit connected to the conductor. As shown in Fig. 1, solar cells are grouped in modules M1-8 supplying a satellite power conductor B through diodes D1-8. The conductors voltage is compared with a Zener diode reference in a differential amplifier AD which supplies an input signal to a conventional A-D converter C. Binary outputs C2-8 control transistors T2-8 which, when turned on, short-circuit respective power modules to provide coarse regulation, and further binary outputs b1-5 control transistors t1-5 which can connect shunt resistors W1-5 to the conductor B to provide fine regulation. In another embodiment, Fig. 5 (not shown), that part of the error signal corresponding to fine regulation is used in analogue form to control the conduction of a transistor connected in series with a single shunt resistor. A similar arrangement, Fig. 7 (not shown), may be used to control a buck-boost circuit connected to the conductor B and supplies by additional solar cell modules and by an auxiliary battery.

Simulation Of Alternator Rectifier Excitation System Using Micromachine And Power Transistor Amplifiers

Abstract: This paper describes the modeling of an alternator with rectifier excitation system on a micro alternator using a novel scheme of control with power transistor amplifiers. The theory of simulation is explained and the salient features of the scheme are outlined. Tests performed on the system have shown the accuracy and reliability of the scheme.

Sump pump assembly

Abstract: A modular sump pump assembly is disclosed that consists of three components--a base module, a power module and a switch module. The base module includes the pump casing and is adapted to be connected to the piping that is utilized for discharging the liquid from the sump. The power module, which comprises the pump impeller, the motor, the connecting drive shaft and related parts can be inserted at the pump impeller end into and removed from the base module by means of a bayonet-type joint so that servicing of the power module can be performed merely by twisting the power module relative to the base module to disconnect the bayonet-type joint, after which the power module can be lifted from the sump. The switch module is connected to the power module so that it also can be serviced merely by removal of the power module from the base module and then, if desired, disconnected from the power module.

Discussion of "Generator and power system performance with the GENERREX excitation system"

Abstract: Increasing pressures to limit transmission facilities while increasing the utilization of remote coal reserves and generating station sites is proving a challenge to the nation's utilities. Delays in obtaining construction permits, intervener actions, and difficulties in obtaining the required capital for financing have added to the challenge. The generator excitation controls can play an important role in achieving the goal of high service reliability under conditions which tend to reduce stability margins. High initial response excitation systems with high ceiling voltage capabilities can produce significant performance improvements, particularly in conjunction with power system stabilizer controls. A new concept featuring a high initial response excitation system has been developed which combines the excitation system power supply as an integral part of the generator design, utilizing common parts and cooling systems. Analytical prediction of the on-line performance of this new excitation concept is a vital requirement for both detailed design of the equipment and confirmation of power system design. Correlation of analytical results with factory test data on the prototype unit, The Montana Power Company Colstrip No. 1, establishes a measure of confidence in the ability to predict performance of this new equipment.

Large tokamak power supplies a survey of problems and solutions

Abstract: The Tokamak load characteristics are far from ideal for a power system. Schemes to adjust the load profile and the peak power loading on the power system, to ease the impact on the network are described.

Direct Coupling of Solar Cell Arrays to Electric Power Networks

Abstract: Results of the investigation of the performance of solar cells when directly coupled to a conventional three-phase power network are presented. This approach dissociates the electricity production problem from the electric energy storage problem. Extensive studies of the required power inverter are performed. Preliminary simulation results indicate that ac power outputs of better than 90 percent of the optimum cell power output can be easily achieved by means of a suitably controlled inverter, thereby justify

High Power Density MHD Generators.

Abstract: : Operating parameters were calculated for MHD generators operating at power densities in the channel of 500 MW/cu m and with power outputs of 30 - 35 MW (nominal). Liquid-fueled generators, using hydrocarbon fuels such as JP-4 or RP-1 and oxygen, and solid fuel generators were investigated. Designs of both liquid and solid fuel generators are described, and estimates of their weights and sizes are given. Operation of generators at power densities of 1000 MW/cu m was investigated. Assessments of feasibility and risks involved in achieving high power density operation are made. A development plan for construction of flightweight high power density MHD generator power supplies is presented. (Author)

Millimeter Impatt Amplifier Optimization for Telecommunication Systems

Abstract: High and moderate power Ka-Band (33-40 GHz) Impatt diode amplifiers for use especially in telecommunication systems have been investigated. We point out the means of obtaining optimal conditions (for SDR or DDR diode parameters and operating conditions) for the principal amplifier characteristics : gain-bandwidth product, output power levels, group delay variations, AM-PM conversion rates. The theoretical results achieved, corroborated by the experimental ones, show the excellent behaviour of these Impatt amplifiers operating in telecommunication systems.

Low cost data communications equipment for use on the electric power distribution system

Abstract: 3. When a map, drawing or chart, etc., was part of the material being photographed the photographer followed a definite method in "sectioning" the material. It is customary to begin photoing at the upper left hand corner of a iarge sheet and to continue photoing from left to right in equal sections with a small overlap. If necessary, sectioning is continued again — beginning below the first row and continuing on until complete.