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Today, asynchronous and synchronous generators with double-link full-power frequency converters are the main options for designing highly efficient three-phase voltage sources with an internal combustion engine (ICE) as a prime mover and a variable rotation frequency as a function of the load. It is required to develop and study the efficiency of the use of an autonomous power-supply station with a variable rotation frequency based on a low-power frequency converter in order to provide a decrease in its cost with the potentialities of saving ICE fuel through controlling the frequency depending on the load. The power station and its control system is described both at a structural and at a functional level. The characteristics of the station have been studied by means of computer simulation with the use of the Delphi software package. To assess the potential fuel efficiency of the power station, a multiparameter characteristic of the YaMZ-238 internal combustion engine has been used. A functional diagram of the power station and a block diagram of its control system without using a rotation-frequency sensor are presented. Timing diagrams for the simulation of its operation with the use of an asymmetrical load, as well as its energy characteristics, are presented. The energy characteristics and potential fuel savings of the internal combustion engine when the power station operates with a symmetrical active-inductive load under the conditions of a multiple decrease in the power of the frequency converter with respect to the nominal power of the load. It is shown that, unlike well-known analogues, the developed power station makes it possible to ensure an at least twofold effective rotation-frequency control range of the internal combustion engine while limiting the nominal converter power to 20% of the nominal load power, which provides preconditions for significant fuel savings. The use of the power-supply station in the proposed design makes it possible to reduce its cost by decreasing the power of the converter and increasing the energy efficiency thereof via controlling the ICE rotation frequency with a satisfactory maintenance of accuracy of the output voltage under the conditions of a significantly asymmetric load. The reliability of the results obtained in the course of the studies has been confirmed by means of computer simulation. [ABSTRACT FROM AUTHOR]

A generator with galvanic coupling of an external DC voltage source, windings of a voltage-boosting transformer energy storage and a high-voltage consumer of current pulses has been developed. The generator contains a switch on an IGBT transistor and two output charged capacitors, which are periodically discharged to a high-voltage consumer when the spark gap breaks. The operability of the generator with a higher output voltage and greater efficiency compared to a commutator transformer-capacitor pulse generator has been experimentally confirmed, especially when using a transformer storage with a reduced coupling coefficient of thewindings. The calculation method gives results that coincide with the experiments and can be used in the design. Generators with an average power of up to 5 kW, an output voltage of up to 10 kV and a storage mass of up to 100 kg can be used to supply high-voltage consumers with powerful current pulses with a repetition frequency of up to 10 Hz with an external source with relatively small DC voltage and power values, when this source does not require the exclusion of galvanic communication with the consumer. [ABSTRACT FROM AUTHOR]

A device for controlling a two-winding polarized electromagnet is considered, and its disadvantages are noted. A circuit for the control of a single-winding polarized electromagnet is proposed in which the disadvantages of the existing control circuit are eliminated. Transient processes of charge/discharge of a capacitor to ensure actuation and reset of a polarized electromagnet are considered. The operability of the proposed circuit based on a composite transistor has been experimentally confirmed. [ABSTRACT FROM AUTHOR]

A generator designed for pulse-frequency power supply of high-voltage technological installations is considered. The generator is connected to an external source with a relatively low constant voltage and power. The generator contains a switch constructed on an IGBT transistor and a transformer as an energy-storage device with a diode "back" connected to the secondary winding and an output capacitor. The operability of the generator model has been experimentally tested, a significant reduction in switching overvoltages and unwanted surges of currents has been obtained, which reduces the likelihood of generator equipment failure. A calculation method has been developed for single-pulse charging of the output capacitor, which makes it possible to determine the resistances, inductances, and capacitances of the generator elements and its voltages, currents, power and efficiency with the active-inductive nature of the load. The calculation method can be used in the design of generators with a power of up to 5 kW and a pulse repetition rate of up to 100 Hz with a pulse energy of up to 50 J. The reliability of the calculation method has been confirmed experimentally. [ABSTRACT FROM AUTHOR]

A method for calculating a switched inductive-capacitor generator has been developed that makes it possible to determine the voltages, currents, power, and efficiency of the generator taking into account the parameters of its elements in a pulse-frequency mode of power supply of an active-inductive load. To increase the efficiency of the generator, the voltage across the capacitor and the power of the generated current pulses in the load, it is necessary to increase the source voltage, the switching voltage of the dynistors (Shockley diodes), the switching frequency and duty cycle, the number of capacitor-charging periods, and the time constant of the inductive storage, as well as reduce the capacitance of the capacitor. A generator with a source voltage of up to 48 V and a current-pulse frequency in a load of 1 Hz can have a pulse energy of up to 12 kJ, an average power of up to 12 kW with an efficiency of up to 0.89 and a pulse power of up to 35 MW. It is possible to connect the generator to a source with an insufficient dc voltage level for charging the capacitor, with the voltage across the charged capacitor (639–3060 V) being able to be tens of times higher than the source voltage (12–48 V). [ABSTRACT FROM AUTHOR]

The method of diagnostics of turn-to-turn insulation, which is based on the model of the weakest link, i.e., an element of turn-to-turn insulation with the lowest electrical strength, has been suggested. To determine the weakest link, it is suggested to use the self-induction EMF property of inductance, in which each coil can generate voltage in the form of a pulse, the power of which can be controlled to prevent the destruction of insulation. The block diagram and algorithm of functioning of the microcontroller device that implements this method of diagnostics of the turn-to-turn insulation of an asynchronous motor have been presented. The experimental setup for studying the suggested method and the dependences of amplitude of self-induction EMF on the interrupting current for controlled inductances have been considered. [ABSTRACT FROM AUTHOR]

The possibility of using equivalent circuits of well-known morphology for simulation of structures with distributed parameters in the frequency and time domains is considered. Special attention is paid to the Π-circuit and to the class of circuits intended for ultrabroadband simulation. The parameters of the circuits were obtained based on the measurements of frequency responses of the structures with further approximation of the measuring results. It is noted that all known equivalent circuits except the Π-circuit are oriented for simulation in the frequency domain. The error of simulation using the Π-section was studied, and it was revealed that using it for ultrabroadband simulation is inadvisable. However, in the time domain, the Π-section provides exact (by Elmore) simulation of the delay time and a negligible error of simulation of the rise time; in particular, when simulating a conductor (a microstrip line) loaded with its characteristic impedance, the Π-section exactly (by Elmore) simulates both the delay time and the rise time; i.e., the relative error of rise time simulation equals zero both for noninductive lines (resistors) and for lines without resistance loss. [ABSTRACT FROM AUTHOR]

Application of parametric control in a dc voltage stabilizing system is considered. Under parametric control, the resistance of items connected in series with a load resistor changes. The resistance control is carried out by changing the relative shunting duration of the resistor with switch contacts occurring with a high frequency. A filter consisting of a choke and capacitor connected between the resistor and the load makes it possible to smooth the voltage ripples at the load up to a permissible level. A limiting continuous model of a voltage stabilizer with an integral controller is constructed. The stationary mode is determined, and the condition of its asymptotic stability is obtained by the linearized equation of perturbed motion. It is revealed that, when secondary power supply sources are used, the parametric control stabilizer has certain advantages relative to a stabilizer with a pulse down-converter. The studies of designed stabilizer by a mathematical model revealed the good coincidence of experimental and designed results. [ABSTRACT FROM AUTHOR]

This article gives a brief overview of current developments in the application of hydrogen sources as part of the autonomous power systems of ships and trains. The variants of the block diagrams of autonomous electric power systems with diesel generators or turbine generators and hydrogen energy sources in which a hydrogen source works in parallel with a synchronous generator for the total load from the inverter of current and inverter of voltage have been considered. The energy performance indicators and features of management processes have been analyzed on the basis of a consideration of equivalent circuits with fundamental harmonics on stationary processes when the synchronous generator works in parallel with a hydrogen energy source supported by means of a current or voltage inverter for an active-inductive energy consumer. Comparative analysis of the advantages and disadvantages of the considered structural variants of autonomous power systems has been provided. [ABSTRACT FROM AUTHOR]

The design of a control system performing the minimization of power losses and temperature checking of a traction electric drive is considered. The transistors and diodes conduction and switching losses and induction motor copper and iron losses are used as losses leading to overheating. It is suggested to use the transistor switching frequency and stator winding current as variables limited by the thermal conditions and power losses. The structures and mathematical description of control system main units are presented. The use of numerical methods for determination of the optimal operating mode is proposed. It is shown that, as a result of use of the proposed system, the reduction in power losses may be increased up to 15% relative to a classical vector control system. [ABSTRACT FROM AUTHOR]

The parameters of an ideal process of suppression of a synchronous generator field are analyzed. The criteria of ensuring a minimal field suppression time are determined. Schematic diagrams of a thyristor field-suppression device are examined. Results of experimental tests of one such device are detailed. [ABSTRACT FROM AUTHOR]

A soft-start method for induction and synchronous motors is considered. The method is based on pulse switching of the motor stator to the supply network at the moments at which the stator- and rotor-flux linkage vectors produce positive electromagnetic torque. A wiring diagram of the experimental soft-start device, its operation algorithm, and experimental outcomes are presented. [ABSTRACT FROM AUTHOR]

A mathematical model of electric ignition for methane-air mixture from a source of sustained power is applied to develop a reliable calculation method for determination of the intrinsic safety of electrical circuits of explosion-proof electrical equipment. A method for rapid calculating of the intrinsic safety for explosion-proof electrical equipment is developed that is suitable for evaluation of a wide class of circuits, including systems with reduced discharge time, based on regression relationships obtained by the preliminary pattern of thermal explosion field. The possibility of using the proposed method is shown by the example of determination of the intrinsic safety of electrical circuits of a dc power supply with high load capacity, which responds to the excess of the modulus for the rate of change of load current strength. [ABSTRACT FROM AUTHOR]

This paper presents a new thyristor-capacitor voltage regulator for a high-voltage pulse generator used in electrophysical installations based on different high-power vacuum electron devices. A thyristor-capacitor voltage regulator enables one to reduce the power intensity of storage capacitors that enter it. Expressions for calculating the parameters of components of the power supply are developed and results of simulation models of the power supply are reported. [ABSTRACT FROM AUTHOR]

A simplified transducer-free realization of electromagnetic gate-inductor electric drives with openloop control systems is proposed with prospective applications for the majority of rotary-, linear-, and alternatemotion-type industrial mechanisms. A functional scheme of the control system for the electric drive under consideration is given. A simplified calculation of the basic parameters of the rotary motion electric drive is presented. The advantages of reducer-free electric drive constructions are shown. [ABSTRACT FROM AUTHOR]