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This article deals with the description of the operating principle of a d.c. to d.c. converter equipped with the thyristors; the converter is designed for a voltage range between 43 and 300 v d.c. The output voltages are stabilized to within 2% and protected against both over-loads and over-voltages. The voltages and currents at the individual outputs are as follows: −48 v/1 A, −24 v/0.7 A, −12 v/2.5 A, −6 v/7.5 A, 6 v/1.5 A and 24 v/0.05 A. Ambient temperature: −25°c to 55°c.

A new instrument for time control and adjustment to be used in computer controlled multicounter experiments is presented. The proposed time-to-digital converter is a parallel unit to the ADC.

The authors have developed a new type single-phase to 3-phase electric power converter, voltano converter. With simple construction it produces fairly well-balanced 3-phase output power from a single-phase power source at high efficiency. The construction and the characteristics of the voltano converter are presented ; the characteristics show that the efficiency is more than 90 percent for a 2kVA voltano converter. The operating mechanism of the converter is explained, presenting a vector calculator, which gives, not only various circuit quantities in steady-state operation, but also an intuitive understanding of the operating mechanism.

The installation of the first 20,000-kw electronic power converter was made in December 1943 at the Edgar Thompson plant of the Carnegie-Illinois Steel Corporation to exchange power between their 25-cycle 44-kv and 60-cycle 69-kv systems, the latter being connected to a large public utility. The converter operates in parallel on both systems with normal generators. This type of converter was selected to obtain its ease and simplicity of control, low contributions to faults, light weight of indoor equipment, high efficiency, and ability to transfer a fixed value of power regardless of departure from normal frequency ratio between the two systems. The converter may have its power output controlled manually or by a power regulator or may reduce the demands for power taken from the 60-cycle utility system. Controls also may be supplied to a typical electronic converter to cause it to share the total load of the receiving system in a predetermined proportion with prime movers. Inherently transferring power in a preselected direction in relation to the departure from normal voltage ratios of the two systems, automatic phase control of grid excitation rapidly compensates for changes in this ratio. The reactive kilovolt-amperes needed for commutation, harmonics, and transformer magnetizing current of both rectifier and inverter is supplied by the synchronous machinery in the steel company's systems. Faults such as arc-backs and ``shoot-throughs'' in the electronic equipment are suppressed in a very short time period. The rectifier cannot furnish current to a fault in its supply system.

In recent years, improving of power factor and reducing harmonic distortion in electrical instruments are needed. In general, a current conduction mode boost converter is used for active PFC (Power Factor Correction). In a PFC boost converter, if a duty ratio, a load resistance and an input voltage are changed, the dynamic characteristics are varied greatly. This is the prime reason of difficulty of controlling the interleaved PFC boost converter. In this paper, a robust digital controller for suppressing the change of step response characteristics and variation of output voltage at a DC-DC buck converter load sudden change with high power factor and low harmonic is proposed. Experimental studies using a micro-processor for controller demonstrate that the proposed digital controller is effective to improve power factor and to suppress output voltage variation.

The voltage-current characteristic of solar cells that provide power for a spacecraft can vary over a wide range. For maximum power transfer from the solar cells to the battery system a power converter has to be designed that adjusts its input impedance to a value equal to the output impedance determined by the operating power characteristic of the solar cells. This paper discusses a circuit and calculations for a design to match this condition. The proposed power converter is simple, lightweight, and reliable and will be used in the Sunblazer satellite.

Worldwide research and development of the high-voltage thy- ristor converter has been actively promoted recently. In order to apply the thyristor converter to a present-day power system, it is necessary to develop a control and protective system suitable for the system and to study an operating ability when troubles develop in the converter and power system. To solve this problem, we manufactured a HVDC simulator by using a thyristor converter simulating a practical converter and we newly developed the control and protective system.

To provide supply voltages for a detector and electronic circuits is a problem which frequently arises in designing a radiation monitor. With portable assemblies, which use primary or secondary batteries, this problem must bo solved by using DC-DC converters. In general, for each supply voltage a separate DC-DC converter may be used, but in some cases a single converter can produce two or more output voltages. The DC-DC converter should have high efficiency and stable output voltage. The two principal reasons for which the output voltage might change its value are the changes of the batteries voltage and of the converter load. The converter which will be described here can stand very large variation of the batteries voltage and produces two output voltages, one for electronic circuits of the monitor, and the other for its GM counter.

F. C. Hanker: There is some question as to the application of the machine described that I want to discuss, particularly on the basis of considerations that Mr. Shirley has outlined. He has given in his paper three considerations. If you will analyze them, you will find the first is applicable to either the synchronous unit or the type described. In the second, in the amount of inductive kv-a. returned to the system appears to be questionable whether the type described is as effective as the straight synchronous, because the induction machine must of necessity receive its magnetization from either the 25-cycle or the 60-cycle system, depending on the voltage condition. That means that you have to compensate for that excitation or magnetization from the line either through other apparatus connected to, say, the 25-cyele system, or an additional machine that would be supplied with the set. If you take existing conditions, it would net be very serious or very harmful to supply the magnetization from the 25-eycle systems but in other cases where the power factor of the 25-cycle load is much lower, then it is a handicap to the machine.

A means of assessing the relative merits of single-ended and push-pull switching converter or inverter stages is presented. The dependency of those merits upon the range of input voltage and output current is set forth. For a single-ended high-frequency converter stage, the relationships among output power, switch current and voltage ratings, input voltage range, and reset voltage reveal the criticality of transformer design. Transformer stored energy considerations for optimum output power dictate absolute control of leakage reactance as well as the shape of the magnetization curve.

By employing simultaneous-conversion coding and time-sharing techniques an analogue-to-digital converter may be constructed which is 33% faster in operation than a corresponding converter of equal representation accuracy using feedback encoding. The paper describes the design and operation of an analogue-to-digital converter capable of 9-bit, pure binary representation (with an accuracy to 0.2%) with conversion times down to 3 μsec.

1. A converter of the proposed type has a high sensitivity, as a consequence of which its output current can be measured directly by an indicating instrument without any amplification; it is simple and reliable. 2. The sensitivity of the converter increases considerably with a decrease of the maximum angle of deflection α0, and in the region encompassing the origin of the coordinates the output current of the converter varies within wide limits but the characteristics iav.l=F(α) can be considered linear. 3. To measure the output current of the converter it is best to use instruments with small internal resistance, since the sensitivity of the converter will be higher; in a certain region of values of R l the sensitivity of the converter does not depend on the load resistance and decreases with its further increase. 4. The sensitivity of the converter increases with the frequency of the supply voltage, and it is desirable to select frequencies lying in the linear part of the converter's frequency characteristic.

The error of a symmetrical converter R-2R is greater than that of an unsymmetrical converter.

The stability analysis of a buck regulator with DC and AC feedback loops has been investigated theoretically for the continuous conduction mode by applying the z-transform method. The analysis has been extended to the discontinuous conduction mode by means of an analogue computer simulation. These last results have been verified successfully on an existing breadboard. It appears that the introduction of the AC loop allows fast transients independent of the output filter parameters and improves the overall stability of the single loop regulator.

Summary form only given, as follows. There are many circuit applications involving the use of transistors where it is necessary, because of the unavoidable presence of vacuum tubes, to have a high dc voltage when only the basic transistor supply voltages are available. This high voltage can be obtained by using a transistor power converter. The power converter is an rf type power supply using a transistor to make the power conversion. Basically it is composed of a transistor oscillator. step-up transformer, dc rectification and filtering. The oscillator operates with a low supply voltage and the frequency may be set high enough so that the transformer and filter components will be small. It is often necessary to operate systems, which may include a power converter, over a wide temperature range. When a constant output voltage from the converter is needed, some form of temperature stabilization must be used to compensate for the change in the transistor parameters. Presented in this paper is a transistor power converter having temperature stabilization to reduce the output voltage variation. The converter uses a P-N-P alloy-junction power transistor to make the power conversion and delivers an output of 0.85 W. The output voltage is 655 V having a variation of ± 15 volts when using a temperature compensating network employing a thermistor. This voltage variation, over the temperature range of -40°C to + 65°C. is small compared to the uncompensated converter that changes from 440-725 V over the same range.

Standardized.control and interface circuits were applied to the three most commonly used dc to dc converters: the buck-boost converter, the seriesswitching buck regulator, and the pulse-modulated paral1el inverter. The two-loop ASDTIC regulation control concept was implemented by using a common Analog Control Signal Processor (ACSP) and a novel Digital Control Signal Processor (DCSP). This resulted in control circuit standardization and superior static and dynamic performance of the three dc to dc converters. Power components stress control, through active peak current limiting and recovery of switching losses, was applied to enhance reliability and converter efficiency.

The local dynamic stability of a PWM buck regulator has been investigated theoretically for the continuous conducting mode and with the aid of an analogue computer simulation for the discontinuous one. A parametric study of the main factors influencing the design and the stability of the control loop has been performed. The discontinuous conducting mode appears to be the most promising.

The power handling portion of most regulated dc-to-dc electronic power conditioning circuits using a single self inductor for energy storage and transfer can usually be represented by one of three basic or canonical circuit forms. The circuit elements, consisting of an inductor, a transistor switch, a diode, and a filter capacitor may be arranged with appropriate topology to yield a voltage step-up converter, a current step-up converter, or a voltage step-up/current step-up converter. The design of a power converter requires making a number of decisions relating to the parameters of the circuit, including choice of semiconductor elements, filter capacitor, magnetic core material, magnetic path configuration and winding wire size. In the past, converter designs generally have required that several trial combinations of core size and permeability be tested by hand calculations. Experience and intuition were relied on to narrow the range of core size and permeability before starting the trial design computations. Recently, several computer-aided procedures have been described for use in the design . of the inductor for a single type of converter) This paper presents the results of the development of a series of nine programs which may be used to design the inductor in each of three basic converter forms in which the transistor switch is cont rolled by a regulator employing a constant frequency, constant on-time, or constant off-time pulse-width modulator. These nine programs, which contain the design algorithms and evaluation segments, are augmented by three additional programs which generate displays on a storage oscilloscope driven by the computer. These displays have proved to be extremely useful in evaluating the characteristics of the various converter-regulator combinations from an overall or global point of view.

Spacecraft power systems utilizing radioisotope thermoelectric generators CRTGs) as primary power sources present an uncommon set of require ments and limitations for interfacing dc-to-dc converters. A converter configuration is presented that complements these RTG characteristics. The circuit is a variation of the basic flyback regulator modified to provide input regulation. The converter has two isolated outputs. One output provides power directly to the spacecraft equipment, while the second is used for battery charging. Design problems addressed are noise generation in long cable lengths between the RTG source and the converter, regulation of the converter input to obtain maximum power transfer from the RTG to the equipment, and provision for two converter outputs while maintaining high efficiency with a simple design implementation. The design of a converter and battery charger used on the Viking Lander Capsule* is presented as an illustration.

A THERMAL CONVERTER, used as a primary element in the telemetering or totalizing of large power loads, is a measuring instrument which generates a direct voltage accurately proportional to the power of the a-c circuit measured. The output voltages of two or more converters may be connected in series and the algebraic sum of the loads so totalized may be recorded or indicated, remotely if desired, by a potentiometer. In principle, the thermal converter comprises an a-c circuit such that the difference in power generated in two heaters is proportional to the measured load; and the temperature difference thus produced is measured by thermocouples. In addition to power the thermal converter may be adapted to measure reactive power, power factor, current, or voltage.

Electrical equipment often requires power supplies which can furnish several regulated d.c. voltages of the same or opposite polarity. This generally implies a multi-winding power transformer with separate rectifiers and regulators for each voltage. This paper describes a novel d.c.-to-d.c. power converter which provides two independently controlled output voltages, of the same or opposite polarity, from a single power handling switching transistor and a single input voltage. The converter can operate with high efficiency. Circuit complexity and cost are significantly reduced as compared to conventional solutions. The dual-output power converter is an interesting example of a relay system with two input and two output variables. A state-space method is developed for the analysis of this system class, and a theoretical and experimental investigation of the converter circuit is undertaken.