Vol 90, No 3 (2019)

The development of digital technologies that are widely used in industry and agriculture imposes increased requirements on the reference voltage sources for a variety of parameters, each of which is important. However, further enhancement of the resolution of analog–digital and digital–analog converters and, hence, the digital signal processing as a whole, is impossible without improving such the noise level quality index of reference voltage sources. This work describes a method and circuit design for constructing a low-noise source of stable dc voltage on the basis of typical microelectronic circuits of voltage stabilizers. The developed circuit design provides a reduction in the output noise level of the reference voltage sources made based on such microelectronic circuits of voltage stabilizers up to the level of intrinsic noise of the operational amplifiers used in the developed device. The developed source of stable dc voltage is characterized by inversion of the output voltage polarity relative to the output voltage polarity of the microelectronic circuit of the voltage stabilizer that is used.

The problems of providing thermal stability of the power semiconductors under the effect of dramatic dynamic current overloading were considered. A new method was proposed of intelligent thermal protection of power semiconductors that is based on the application of the equivalent thermal time constant of the power device physical structure determined by the transition function of the thermosensitive parameter.

The use of Pareto optimization for autonomous power supply systems is proposed as a method of distinguishing a set of dominant solutions. The fields of application of such approach are considered. A mathematical treatment of a search for the set of alternatives based on the preference and ordering relation is presented. Processing of information is based on the known rules of the logical induction, and the logical formulas act as a finished product. The predicate calculus is recommended applying as a mathematical base. The concept of one system dominating over another is defined on the basis of the binary relation approach. An algorithm for obtaining a set of dominant solutions is developed. The drawbacks inherent in this approach are noted.

The article presents the results of scientific research on solving the problem of reducing the starting currents of induction motors with a squirrel-cage rotor. Theoretical and technical aspects of the solution are discussed. The possibilities of solving the problem on sets of parametrically homogeneous cells and parametrically inhomogeneous cells are analyzed. The use of a parametrically inhomogeneous cell allows for the start-up period to generate additional spectra of the harmonics of the current and cell fields, thus replenishing the field of differential scattering of the rotor. Inductive resistance corresponding to additional scattering is designed to limit the starting current and practically disappear in operating conditions. Analysis of the question shows that the possibilities of a homogeneous cell in this respect are very limited and are represented only by one basic spectrum of harmonics. The results of simulation of currents in a cell with different distribution of inhomogeneous elements are presented. The results of simulation of current displacement in the region of inhomogeneity are also presented. The resulted results testify that the problem of decrease in a starting current of asynchronous electric motors is solved theoretically and technically.

The use of advanced structural concepts for development of electric power equipment of dc traction power supply systems allows one to triple the power density per unit volume. An armored rod radial–cylindrical magnetic system with massive nonlaminated design elements, which is split into sections by nonmagnetic gaps, allows one to provide high mechanical strength without using additional fasteners and pressing elements. This design also provides an admissible level of hysteresis and eddy current losses, as well as meeting the requirements for unconditional linearization of a magnetic flux in the range of working currents. The latter is caused by the performance of smoothing reactors as parts of high-power rectifiers that feed rolling stock.

A new concept for constructing a control system of power electromagnetic devices (PEDs) is considered. The system is based on using additional high-frequency (HF) electrodynamic processes in a PED magnetic conductor. To implement the proposed principle, the PED is equipped with units of dipole C‑antennas covering the magnetic conductor of a PED and made in the form of a detachable spatial capacitor on the outer surface of the carrier dielectric base of which multisection spatially distributed plates are located. An external HF low-voltage source is connected to these plates. When operating the PED in its magnetic conductor, there are two independent electrodynamic processes: a low-frequency (LF) process, which is defined by the operating current of the PED, and the HF process, which is excited by C-antennas. In addition, the PED acts as an electromagnetic sensor recording the desired parameters of HF electrodynamic processes, which determine both the state of the magnetic conductor of the PED and the current state of the PED itself. Based on the Maxwell’s equations and the Umov–Poynting theorem, mathematical models describing the physical processes occurring in the electromagnetic system under consideration were derived that take into account the structural features of the PED and the unit of dipole C-antennas. A variant of circuit design of the control system of the PED under consideration is proposed, which makes it possible to record different informative parameters directly related to the current state of the PED. The proposed notion of constructing the control system is universal; in fact, it has no limitations when applying to different types of PEDs and can be widely used in the relevant industries to the control of parameters of electromagnetic couplings and brakes, solenoid valves, linear positioners, locking devices, etc.

To feed a pulse modulator with quickly changing pulse duration, it is necessary to have a power supply source that will ensure voltage stability at uneven energy consumption due to rapid changes in pulse duration. A pulse modulator is an electrical device designed to convert the energy of mains-frequency voltage to the energy of high-voltage pulses. The power supply source wiring diagram compliant with energy-saving requirements consists of an adjustable mains rectifier, a primary energy storage adjusted by pulse-width modulation (PWM), a high-frequency (HF) bridge inverter, a stepup transformer, a high-voltage (HV) rectifier, and an intermediate secondary storage running in the saturation mode of a time-adjustable HV HF compensatory voltage stabilizer based on a hard-controlled switch, e.g., an electron beam valve or an assembly of HV transistors that provide cutoff of the charging current of the output storage capacitor of the resonant charging circuit of formative lines upon reaching the rated voltage value. The power supply source will have a servo system of charge voltage control and an efficiency of at least 95%. Computerized modeling allows optimizing the design parameters of electrical elements of the power supply source circuit and types of component parts of the circuit’s electrical elements so as to achieve the minimum prime cost and maximum reliability. The best kind of modeling is in EWB and Multisim.

Asynchronous electric drive with vector control is described by a system of nonlinear differential equations. The analysis of vector control uses a model of an ideal asynchronous machine (with a sinusoidal distribution of magnetic induction in the air gap), where the coefficients of mutual magnetic communication between the windings are calculated by means of the cos(θ) function. Simulation in MATLAB has shown that the processes significantly depend on the type of windings. The type of windings is taken into account in coefficients of the magnetic coupling between the windings k_MA(θ). If the function of cos(θ) is replaced with the product of cos(θ)KAa(θ) = k_MA(θ) in the equations of the model of an ideal asynchronous machine, then the type of windings of the asynchronous machine will be considered by a correction function KAa(θ). The coefficients of the magnetic coupling between the windings (the ratio of the magnetic flux connections of the windings) were calculated by a modified method of conducting the gear contours. Dimensionless correction functions allowed specifying the vector transformation of Clarke and Park.

The periodic growth in megacities has incremented the power consumption in the name of modernized techniques and hustle-free lifestyles. In the state of Tamil Nadu, the voltage and power regulation has created a drastic decrements in the efficiency for the tail end consumers. Thus, resulting in shortage of voltage and vehemently opposing the performance factors of home appliances, micro-industries and minute gadgets used on a day-to-day basis. In this paper, a solution is provided to magnificently ameliorate by catering a high voltage distribution system, simulating its results for serving, good to the Tamil Nadu Electricity Board having fed by the Electrical Transient Analysis Program Software. Therefore, in reference to the contingent PSO algorithm enabling to convert Low Voltage Distribution System to High Voltage Distribution Systems, sufficiently acquiring a redemption for utmost performance usage of the transformer. The relational composition of the supply in the LVDS and HDVS magnitudes demonstrate the necessary output demands. The line losses vividly broadcast the allocated transformer and the HDVS holds good in showcasing power loss in advanced tail and voltage prescriptions.