Showing papers on "Converters published in 1983"

Small signal analysis of resonant converters

Abstract: It is known that the dc-to-dc conversion ratio of resonant converters can be controlled by changing the ratio of switching frequency to resonant frequency. In this work the small signal response of resonant converters to small signal perturbations in the switching frequency and input voltage is determined.

Synthesis of switched-mode converters

Abstract: An analytical synthesis method is described which is capable of generating the complete set of switching converters which possess given attributes. This leads to a number of useful new converter topologies, as well as to a more fundamental understanding of switched-mode conversion. Two examples are considered. It is found that the class of single-inductor two-topology converters contains seven basic members. In addition, a class of converters with nonpulsating input and output currents also contains seven members. Zero input or output current ripple may be obtained in three of these converters.

Self-calibration technique for A/D converters

Abstract: Linearity errors of weighted capacitor digital-to-analog converters (DAC's) can be corrected using a simple digital algorithm. The additional circuitry required is approximately 350 digital gates plus 10 bytes of memory space.

Noise Source Equivalent Circuit Model for Off-Line Converters and its use in Input Filter Design

Abstract: As a s t e p toward d e s ig n in g a f am ily o f power l i n e i n t e r f e r e n c e f i l t e r s d e d i c a t e d f o r o f f l i n e sw i t c h in g mode power s u p p l i e s , an e q u i v a l e n t c i r ­ c u i t was developed t o d e s c r i b e t h e t y p i c a l c h a r ­ a c t e r i s t i c s of t h e n o i s e source e x i s t i n g a t th e AC t e r m i n a l s of t h e s e s u p p l i e s . The model uses l i n e a r e l em en ts t o p r e d i c t t o a f i r s t o rd e r th e behav io r o f RFI f i l t e r s as a p p l i e d t o sw i t c h in g mode power s u p p l i e s . C o n s o l i d a t i n g b a s i c f i l t e r and matching c i r c u i t a n a l y s i s with t h e e q u i v a l e n t n o i s e s ou rce c i r c u i t f a c i l i t a t e s t h e development o f an optimum RFI f i l t e r f o r sw i t ch in g mode power s u p p l i e s .

Line Harmonics of Converters with DC-Motor Loads

Abstract: The line current and voltage harmonics generated by thyristor dc-motor drives, in particular with 3-phase 6-pulse dc converters, are analyzed. As industry continues to raise the power level of the converters, it is becoming more and more important to find techniques for calculating the current and voltage harmonics that avoid making the often unrealistic assumptions of the procedures used in the past. Yet these techniques must maintain, in as simple a form as possible, all the necessary curves and expressions for predicting them under the required conditions. A more accurate model of the line- current waveform is analyzed allowing for both the overlap angle and dc-current ripple, and the results are presented as a convenient set of graphs and also as a set of mathematical expressions for use on a programmable calculator. The calculated current harmonics are then used to derive the corresponding voltage harmonics toegther with their phase relationship. These voltage harmonics are then reconstructed into the relevant voltage waveform on a plotter.

Class-E resonant regulated DC/DC power converters: analysis of operation, and experimental results at 1.5 MHZ

Abstract: We present analytical results, design considerations and experimental results at 1.5 MHZ, for a novel, resonant, high-frequency de/de converter. The circuit works virtually without dynamic losses at several-MHz switching frequency. The analysis gives the permissible area of the equivalent load impedance for lossless operation, presents a model for regulation by narrow-band frequency control, and characterizes the output full-wave rectifier. Experimental data from a 1.5-MHz, 40-W converter verify the results of the theoretical analysis. The measured efficiency was 85%.

Ceramic honeycomb catalytic converters having high thermal shock resistance

Abstract: A heat resistant and thermal shock resistant ceramic honeycomb catalytic converter for purifying automotive exhaust gas and the like is constructed by arranging at least one ceramic honeycomb structural body, having a dimension of 0.10≦L/D≦0.40 wherein L and D are respectively a length and a diameter of the ceramic honeycomb structural body, upstream of and adjacent to another ceramic honeycomb structural body in a metal casing.

Switched-capacitor second-order noise-shaping coder

Abstract: The rapid development of digital processing in the fields of instrumentation, control and communications has generated a good deal of research into simple, easily integrable, high-resolution A/D converters. Given the significant promise such converters offer for future application, a switched-capacitor version of a second-order noise-shaping coder intended for high-resolution conversion has been realised. This coder has been used successfully to produce a PCM signal.

Current Fed and Voltage Fed Switching DC/DC Converters - Steady State and Dynamic Models their Applications in Space Technology

Abstract: This paper is a contribution in the developments. of the steady state equations and dynamic representation of current fed switching structures (buck, boost) in continuous mode. The basic principle for the mathematical modelling is the first order expansion of the transition matrices. A comparison with classical voltage fed power cells shows an higher degree in the system transmittances as the consequence of the introduction of a new system variable the input capacitance voltage. Validations are realised on a breadboard PWM shunt regulator.

A new flyback DC-to -three-phase converter with sinusoidal outputs

Abstract: Systematic extension of any dc-to-dc converter leads to its dc-to-three-phase equivalent characterized by sinusoidal output voltages and fast dynamic responses. This genralization principle is illustrated for the special case of the flyback topology. State-space averaging has modeled with a high degree of accuracy the performance of dc-to-dc converters. Here it is combined with the stationary-to-rotating coordinate transformation, customarily used in plyphase ac systems, to results in an effective analysis method for switched-mode dc-to-polyphase converters.

Design Considerations in Multi-Output DC-DC Converter with Magnetic Amplifiers

Abstract: Multiple output dc-dc converters, that take advantage of cross-regulation, are useful power supplies for electronic equipment which require several regulated voltages with good isolation. However, since regulation errors are contained in the cross-regulated outputs, they should be stabilized to obtain a precisely regulated output. Magnetic amplifiers are suitable for this purpose, but no quantitative design method has yet been fully established. This paper proposes utilization of magnetic amplifiers to compensate for cross-regulation errors in the multi-output dc-dc converter, and describes SR optimum design conditions presenting a suitable cross-sectional area and number of turns for the SR. Further, it is also clarified that SR core can be reduced in size by utilizing an amorphous core and increasing the operating frequency.

A Microprocessor-Based Synchronization Scheme for Digitally Controlled Three-Phase Thyristor Power Converters

Abstract: This paper presents a microprocessor-based scheme that generates the necessary synchronization logical signals for three-phase static power converter control systems. The problem of detecting the phase-to-phase voltage zero-crossing in presence of noise generated by thyristor commutations in constant and in variable frequency supplies is discussed, and a microcomputer software solution is proposed.

Ferroresonant converters with high-frequency drive

Abstract: Ferroresonant type dc-to-dc converters driven by 500kHz are presented. Means to reduce the switching loss in the transistor inverter and to reduce the dissipation in the regulation circuit are discussed.

A New Fast-Response Current Control Scheme for Line-Controlled Converters

Abstract: The drawbacks of closed-loop current control for line- controlled converters are eliminated by generating close to optimal firing pulses in a feedforward channel The steady-state and dynamic nonlinearities of the converter and the dc motor load are compensated A standby closed-loopcurrent controller is activated only in the presence of disturbances Experimental results show excellent dynamic performance at all operating points of a noncirculating current four quandrant drive

Synthesis of Optimum Gain Functions for Static Power Converters

Abstract: The optimization of transfer characteristics of static power converters has been largely based on converter definition in terms of its circuit configuration. Since converter circuits lack mathematical definition, this approach has failed to produce a comprehensive optimization procedure. Instead, it has led to several unwieldy optimization schemes with limited range of application. A different approach, which employs a more effective converter definition, is discussed. With this, approach, the converter is defined in terms of its ideal gain function, which has an exact mathematical definition. An optimization procedure transforms the ideal gain function into an " optimum" gain function compatible with the switching characteristics of static converters. This procedure is subsequently employed with various classes of static converters to obtain their respective optimum gain functions. A thorough analysis of the resulting converter characteristics demonstrates the effectiveness of the proposed optimization approach. In particular, converters with optimum gain functions are clearly shown to generate the minimum possible (for switching converters) harmonic distortion.

Diagnostic apparatus for digital-to-analog converters

Abstract: An apparatus for diagnosing a plurality of digital-to-analog converters simultaneously is provided. Digital signal generation means applies digital signals to the plurality of digital-to-analog converters, and the digital signals are changed in sequence so that the analog outputs from the converters are changed symmetrically with respect to a first predetermined value. The analog outputs from the converters are combined by a resistor network, and the combined output is compared with a second predetermined value by a comparator. If the comparator's output is kept to a predetermined level regardless of changing the digital signals, the digital-to-analog converters are judged that they operate properly.

Pressure transmitting device

Abstract: PURPOSE:To switch the range of measurement quickly and automatically, by selecting automatically a pressure converter which is used together with a pressure converter for full range of measurement anc corresponds to a part of the range of measurement. CONSTITUTION:The output of a pressure converter 11 for full range of measurement is applied to a logical arithmetic circuit 22 via an A/D converter 21 and stored in a storage circuit 23. At the same time, the circuit 22 gives compensation to the digital pressure data with reference to the compensating data stored in the circuit 23. Based on this compensated data, the working range is read out for pressure converters 12-14 which divide equally the full measuring range stored in the circuit 23, and the converters 12-14 corresponding to the range of measurement are selected via a multiplexer 19. Then the electric power is supplied to the selected converters 12-14, and the outputs of these converters are delivered via a converter 21, the circuit 22 and a D/A converter 24. In such a way, the range of measurement is automatically switched in a short time, and the highly accurate pressure is converted into the electric quantity to be transmitted.

Control Methods for Reducing the Inductance in the DC Link of Current Source Inverters

Abstract: With regard to less expenditure, fewer losses, and less weight, the dc choke in the link of current source converters must be kept small. The performance of the dc link and special control methods for minimizing the link inductance are investigated. The converter is connected on the first side to a three-phase ac machine. On the second side, different types of line-side converters can be chosen for-operating at a dc supply as well as at a single- and a three-phase ac supply. According to the different performances in the dc link depending on the line-side converter, different control methods are presented to minimize the inductance. Thus considerable improvements can be achieved. Results of measurements of the test drives are given.

Photovoltaic conversion of laser to electrical power

Abstract: Transmission of power in space using lasers will require devices for converting the laser power to electrical power. One such type of device for accomplishing this is the photovoltaic converter. This paper reviews photovoltaic converters and their application for conversion of monochromatic laser power to electrical power. Laser power densities greater than 1000 W/sq cm are considered. For a converter operated at 300 K a lower bandgap limit of 0.67 eV (1.80 micron) is defined. For ideal conditions, an efficiency of 47.8 percent is calculated for Nd/Liquid laser radiation incident on an Si converter. Several types of photovoltaic converters are discussed. Series resistance is identified as a major problem. Vertical multijunction converters are the most promising photovoltaic devices for use as laser to electric power converters.

Circuit arrangement for telecommunication installations, especially for telephone exchange installations, with direct voltage converters

Abstract: Cuk converter with input inductance (L1; L3, L4; H1, H2) and output inductor (L2, L4, L6, H3, H4, H5, H6, H7, H8), and this connective storage capacitor (C1; C5; K1, K4, K7) is (with an inserted in the current feedback path further storage capacitor C2; C6; K2, K5, K8) equipped, which has a direct-voltage potential separation between the load (a1 / a2; a3 / a4; a5 / a6, a7 / a9, a9 / a0) (e1 / e2, e3 / e4; e5 / e6) and DC voltage source accomplished.

Analysis and Steady-State Behavior of an Optimized AC Converter Machine

Abstract: AC machines presently designed to operate from a solid state power converter retain a sinusoidal winding distribution even though such machines were originally intended only for operation with sinusoidal rather than rectangular power supplies. This paper describes a unique type of concentrated winding machine in which the winding distribution is intentionally rectangular to better accomodate the rectangular waveforms of conventional six pulse converters. Equations which define steady state are derived and compared with tested results on an actual prototype. Both generating and motoring modes are investigated and conditions are identified for optimal operation of this new machine.

Three phase a.c. to d.c. voltage converter with improved power line harmonic current reduction

Abstract: A three phase a.c. to d.c. voltage converter is disclosed. First, second and third rectifier circuits rectify respective phases of a three phase a.c. source into respective varying d.c. voltages. First, second and third converters connected to the output of the first, second and third rectifier circuits, respectively, each converting the varying d.c. input generated by its associated rectifier circuit into a substantial d.c. voltage. Each of the converters also generate at least one isolated d.c. voltage. At least one of the isolated d.c. voltages is applied to the input of each of the converters to reduce the harmonic currents fed back into the a.c. line.

Circuit arrangement for fail-safe power supply

Abstract: The invention relates to a fail-safe power supply for data processing channels, in which a plurality of equal-power DC converters covering the rated load plus at least one further equal-power DC converter are provided to supply power to each data processing channel, which converters are connected on the input side and on the output side, via a coupling unit to the supply voltage and feed the data processing channel.

Modified Sequence-Control Technique for Improving the Performance of Regenerative Bridge Converters

Abstract: A modified sequence-control technique for series-connected regenerative bridge converters, for improving the performance at line and load terminals, is described. The reactive power is minimized by operating the fully controlled converters with the half-controlled characteristic, grading the input voltages to the bridge converters, and adopting the control strategies such that the converter with minimum input voltage operates over the full range of thyristor firing angles, whereas the firing angles of other converters are restricted to values corresponding to their ratings. Two control strategies are described. The comparative evaluation of the proposed technique with the existing techniques is also presented.

An adaptive start-up control law for DC-TO-DC converters powered from a current-limited source

Abstract: This paper introduces an adaptive start-up control law for dc-to-dc converters powered from a current-limited source. This control law permits the static turn-on characteristics of the converter to be easily and accurately designed. The controller then adapts the dynamic characteristics of the converter to stay within the capabilities of the source. As a result, this adaptive control law ensures a successful system start up over a wide range of source and load conditions. In addition, the output voltage is guaranteed to increase monotonically with time. These performance features are particularly useful in distributed powering systems, because they permit a single design to serve the needs of many different applications. The expressions derived in this paper to predict the static and dynamic start-up performance of a dc-to-dc converter are shown to be in good agreement with experimental measurements. Finally, a comparison of this control law to other popular start-up techniques demonstrates the usefulness of its adaptive features.

A/d converting circuit

Abstract: PURPOSE:To reduce correlative errors, by inputting outputs of sample holding circuits of one or two systems to plural latch type A/D converters connected in parallel and processing these outputs CONSTITUTION:A high-band analog signal ea from a terminal 20 is inputted to a sample holding circuit 22 through a buffer 21 and becomes a sample voltage eSH in the circuit 22, and this voltage eSH is supplied to latch type A/D converters 24a-24d through an amplifier 23 Converters 24a-24d quantitize the voltage eSH by four-phase clock signals phi1-phi4, and the quantitized amplitude value is encoded by an encoder before the next clock signal is inputted, and code signals D1-D4 are held in a latch circuit in time division Signals D1-D4 become a digital signal D corresponding to the signal ea by a parallel-serial signal converter 25 Since the circuit 22 and the amplifier 23 are formed in one phase, the same sample voltage is applied to converters 24a-24d, and analog signals of the same level are not converter to different codes