RU2725412C1 - Method of direct current transformation - Google Patents

Abstract

FIELD: electrical engineering.SUBSTANCE: method of direct current transformation relates to electrical engineering and can be used for operation with low-voltage direct current sources and is used to provide DC power to a wide range of industrial, transportation and domestic consumers. According to the invention, the low voltage of the primary DC source is converted into a high voltage which is generated on the set of DC-series capacitors which form the output circuit of the transformer, each of which is powered from the primary DC source, wherein output circuit capacitors are fed in turn by interconnection of said capacitors to primary direct current source. Method is environmentally safe.EFFECT: technical result is increase in efficiency and simplification of DC transformation process.3 cl, 2 dwg

Description

The invention relates to electrical engineering, in particular, to methods for converting electricity and can be used to work with low-voltage direct current sources and is used to provide direct current electricity to a wide range of industrial, transport and domestic consumers.

Widely known are various methods for producing electrical energy that convert one type of energy into electrical energy: electrochemical, thermoelectric, magnetoelectric, piezoelectric, photoelectric, using nuclear energy, and others (see. "Great Soviet Encyclopedia". -M .: Publishing House "Soviet Encyclopedia ", 1978, T. 10. S. 580-581). However, not all sources of electricity can be directly used to power consumers. A separate urgent task is the coordination of the output parameters of current sources with the requirements of consumers. For example, chemical sources, thermionic and thermionic energy converters, unipolar generators such as a Faraday machine and several others require the conversion of a low output DC voltage to a higher one. In particular, there are problems of adaptive conversion of a substantially unstable output voltage of a direct current source, for example, when using supercapacitors (ionistors) to power electric motors in vehicles and other devices designed for a certain input voltage.

Most often, two methods are used to convert low DC voltage to constant high and ultra-high voltage: using electrostatic generators with a mechanical charge conveyor such as a Van de Graaff generator and using various devices including step-up transformers and AC rectifiers. The scope of electrostatic generators is limited by their relatively low power and low efficiency of the installation. In the second case, to obtain a high DC voltage, one or another combination of intermediate DC to AC converters, step-up transformers and rectifiers, called cascade generators, is used. Common problems for them are the low efficiency of power conversion, the complexity and unreliability of the device.

At the same time, direct capacitive (capacitor) methods for increasing DC voltage are known. So, in the high-voltage technique, an Arkadyev-Marx pulsed high-voltage generator is used, the principle of which is based on charging electric capacitors connected in parallel, which after charging are connected in series using various switching devices (for example, gas arresters or thyratrons). Thus, the output voltage increases in proportion to the number of connected capacitors (see Sirotinsky LI (ed.) High Voltage Techniques. 4.1. -M: SEI, 1952. p. 264-282; MT Pichugina High-voltage electrical engineering. - Tomsk: TPU Publishing House, 2011.p. 4-14).

Arkadyev-Marx generators make it possible to obtain pulsed voltages from tens of kilovolts to several millions to tens of millions of volts. The pulse energy of these generators varies widely and can start from values in tenths of a joule and reach values of tens of megajoules.

The main disadvantage of the Arkadyev-Marx generator is that to obtain high voltage it must contain 5-8 stages, with the same number of spark switches, which is associated with a deterioration in specific energy and mass-dimensional parameters and a decrease in efficiency. In the discharge mode of the Arkadyev-Marx generator, losses are the sum of losses in capacitors and spark gaps. To reduce losses, they strive to reduce the resistance of spark generator switches, for example, by placing them in an electrically strong gas under pressure, use capacitors with high quality factor, optimize breakdown initiation to achieve minimum breakdown gradients, etc. In addition, this Generator does not provide continuous operation.

The closest in technical essence to the present invention is a capacitive dc transformer of electrostatic type selected as a prototype with a rotating cylindrical dielectric rotor and brush current collectors, in which the contact brush assemblies in the input circuit are connected in parallel and serve to apply electric charges to the rotor, and in output in series and are used to remove high voltage, moreover, the contact-brush devices of the input and output circuits are arranged alternately one after another to feed the secondary circuit at each last stage (see. "DC capacitive transformer", AS USSR RF No. 156598 , IPC H02n, Class 21d ¹ , 13, 1962). In this invention, the input DC current is continuously converted to a direct current of an increased voltage that exceeds the input by the number of stages in the secondary circuit.

The disadvantage of the method used in this invention is the low energy conversion efficiency associated with losses when using a rotating rotor and brush current collectors, as well as low output power and non-adaptability to changes in the current consumption of the payload and the parameters of the primary supply voltage.

The objective of the invention is to increase the efficiency and simplify the process of transformation of direct electric current.

The problem is achieved by converting the low voltage of the primary DC source to high voltage, which is created on the aggregate of series-connected capacitors forming the output circuit of the DC transformer, each of which is fed from the primary DC source, moreover, the output circuit capacitors are fed alternately by periodic connecting each of them to the primary source of direct current.

The essence of the invention consists in replacing a complex electrostatic method for converting DC voltage to a method based on the known methods of capacitor transformations of electricity carried out in a continuous mode.

So, from the course of general physics it is known that when n capacitors are connected in series with voltages Ui, a circuit with a common voltage U _Σ equal to the sum of the voltages of individual capacitors is obtained (see Landsberg G.S. (ed.) Elementary textbook of physics. T2. 13 -th ed. -M.: Fizmatlit, 2008.p. 83-85):

It is also known that the discharge process of a capacitor of capacitance C at an ohmic load R is dynamic, described by an exponential law (see I. Savelyev, General Physics Course. T2. -M.: Lan, 2008. S. 242-243):

where, Un is the initial voltage across the capacitor.

Thus, if we connect n capacitors in series with some average voltage Ucp, and ensure that this average voltage level of individual capacitors is maintained from the primary current source with voltage Uo, we obtain a capacitive DC transformer operating in continuous mode with an output voltage Uout:

At the same time, it is possible to feed the individual capacitors in turn, periodically connecting them to the primary current source. It is obvious that the condition for the normal functioning of such a current transformer, following from the energy conservation law, is a significant excess of the current value of the primary current source I ₀ over the value of the output current of the transformer I o:

The ways of implementing the inventive method for transforming direct current will be considered using an example of the operation of a possible design of a transformer shown in the figures of FIG. 1 and FIG. 2.

The capacitive DC transformer contains capacitors 1, Ci (i = 1 ... n) of the output circuit, from which the output voltage Uout is determined, determined according to expression (3). These capacitors are fed from the primary current source 2 through the ballast resistance Rb, limiting the charge current of the capacitors passing through the contact groups 3, Ki-1,2 (i = 1 ... n) of the switching devices 4, Ki (i = 1 ... n). Switching devices 4 are switched alternately by a ring pulse counter 5, receiving a pulse signal from the pulse generator 6.

The operation of a capacitive DC transformer is as follows.

When the load is connected to the transformer, a joint discharge of each capacitor occurs in its output circuit, as shown in FIG. 2. After a period of T, in turn, each of the capacitors 1 of the output circuit is connected to the primary current source 2 for a time interval ΔT = T / n, during which the charge of the connected capacitor and voltage are restored to the original Uo. Thus, by periodically recharging the capacitors 1, the required average charge level is maintained with a voltage Ucp.

The device of the transformer allows you to adaptively adapt to changing operating conditions. In particular, the increase in the current consumption of the load is counterbalanced by a proportional increase in the frequency of charging the capacitors of the output circuit by increasing the frequency of the pulses of the pulse generator 6 with a corresponding reduction in the period T. The decrease in the voltage of the primary current source 2, for example, when using supercapacitors (ionizers) as such, can be compensated inversely by an increase in the number n of capacitors 1 of the output circuit of the transformer.

The transformer device is reversible and allows you to lower the voltage. In this case, the input and output voltage are interchanged.

Using the proposed method for transforming DC gives, in comparison with existing methods, the following technical result:

allows you to simplify the design of devices that increase the DC voltage;

provides consumers with high voltage in a continuous mode without fundamental power limitations;

more economical in comparison with existing methods, has a higher efficiency;

is an environmentally friendly way to convert electricity.

Comparative analysis with the prototype shows that the proposed method for transforming DC currents is characterized by a different, simpler and more economical technology, implemented by converting the low voltage of the primary DC source to high voltage, which is created on the aggregate of the series-connected capacitors forming the output circuit of the DC transformer, each of which is fed from the primary source of direct current, moreover, the feeding of the capacitors of the output circuit is carried out in turn, by periodically connecting each of them to the primary source of direct current. The method does not use any moving mechanical units and contact-brush current collectors, does not have fundamental power limitations.

Thus, the present invention meets the criteria of "novelty" and "inventive step".

The prospects for the industrial application of the invention do not cause difficulties, since the proposed method consists of the combined action of the capacitive energy conversion and switching electrical circuits known and widely used in electrical and radio electronics technologies, and also does not require the use of any means, materials or elements unknown to the modern industry.

In particular, it is advisable to use solid-state power switch designs based on field-effect transistors with an insulated gate, having high speed, the ability to work with high currents and voltages with minimal control costs (see Gusev V.G., Gusev Yu.M. Electronics and microprocessor technology. -6th ed., Sr. - M.: KNORUS, 2013.S. 570-583, 677-681).

Claims (3)

1. A method of direct current transformation, including the creation of a high voltage on a set of capacitors connected to the payload of the DC transformer output circuit of series-connected capacitors, each of which is alternately energized by periodically connecting to the primary DC source, characterized in that the output circuit capacitors are recharged from the primary DC source is carried out at intervals that provide the desired value of the supply voltage of the payload. 2. The method according to p. 1, characterized in that the frequency of feeding the capacitors of the output circuit is reduced with increasing power consumption of the payload of the transformer and, accordingly, is increased with its decrease. 3. The method according to PP. 1, 2, characterized in that the number of capacitors of the output circuit is increased or decreased inversely with the change in voltage of the primary DC source.

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