RU2310253C2 - Method for direct conversion of heat into three-phase electrical energy - Google Patents

Abstract

FIELD: heat energy direct conversion into electricity for power supply to buildings in metallurgy and transport where frequency-regulated electric drives are required.

SUBSTANCE: proposed method intended for direct conversion of heat energy into three-phase electricity, for instance, to generate electrical energy by evaporation of electrons in vacuum due to heat of gases produced in fuel combustion is characterized in that phase shift, frequency, and waveform of output voltage of thermionic generator incorporating thermionic elements disposed in the form of multi-deck battery washed by coolant flowing over spiral path are specified by control pulses distinguished by amplitude whose length equals that of intervals. Thermionic elements are periodically thrown in operation by pulses; they are grouped in compliance with number of phases and connected in parallel networks within each group; even number of minimum four networks in one phase is specified, half of them being differentially connected. Part of networks of one direction are differentially connected affording connection of other part of networks.

EFFECT: enhanced effectiveness of heat conversion into adjustable-frequency three-phase power whose output voltage waveform is close to sine wave.

1 cl, 5 dwg

Description

The claimed invention relates to the field of energy, and specifically to the direct production of electrical energy from the heat of combustion of fuel by thermionic emission, and can be used to supply electrical energy to industrial and domestic facilities, as well as for a frequency-controlled electric drive of alternating three-phase current.

A known method of converting thermal energy into electrical energy, consisting in the following. In a vacuum chamber containing a cathode thermally connected to a heat source, a current-collecting electrode of a mesh structure is arranged, and the anode is placed outside the vacuum chamber, above the current-collecting electrode. The collector electrode is periodically connected using a switch with a capacitor that accumulates the electrical energy of the converter. In the pauses between the current collection cycles, the capacitor through the same switch is connected to the winding of the output transformer, which converts direct voltage to alternating voltage. In the same pauses, positive high voltage pulses from the rectifier, which is connected to the transformer, are supplied to the anode. Positive pulses periodically suck out the opposite charge from the cathode and increase its emission activity, while the payload is connected to one of the transformer windings [RU patent No. 2087990, IPC 6 H01J 45/00, 1997].

The conversion of thermal energy into electrical energy by a known method is carried out by heating the cathode located in the vacuum chamber of the Converter, the flow of coolant supplied from the outside of the heater chamber from a heat source. Useful work in the external circuit is accomplished by electrons leaving the heated cathode and accumulating on the electrode of the mesh structure in the form of a negative charge.

In the known method, the method of obtaining intermittent motion of a stream of electrons of thermal emission is used with the conversion of motion into alternating current in a load. The disadvantages of this method are as follows. The Converter, built according to the known method, has a low efficiency of converting thermal energy into electrical energy, the efficiency (efficiency) of the converter does not exceed 10%. This is due, first of all, to the irrational use of heat energy from the heat carrier flow. In the converter, only a small part of the heat input is converted to electrical energy. The bulk of the heat flux passing through the converter is diverted from the mesh electrode and the anode to the environment where it is scattered. The form of the load voltage obtained from the transformation of unipolar discontinuous pulses is far from the required sinusoidal shape, it contains high-frequency harmonic components that overload the electric network, being a source of additional losses of electric energy.

A known method of direct conversion of thermal energy into electrical energy and a thermionic generator for its implementation, the closest in its physical essence to the claimed method is a prototype. In the known method, the conversion of thermal energy into electrical energy is carried out through the flow of a moving heat carrier, which is supplied to the thermionic elements. They are placed in a sealed enclosure of a thermionic emission generator in the form of a multi-storey battery with the possibility of forming a spiral trajectory of the flow of coolant along the floors of the battery, which are separated from each other by channels. The coolant flow is passed through the first channel, heating the emitters of thermionic elements of the first floor, at least to the temperature of thermal emission of electrons. At the outlet of the channel, the coolant flow through the bypass line channel is fed to the input of the next channel in the same direction as the coolant flow of the previous channel. At the same time, the same coolant flow is simultaneously used to heat emitters of the next floor and as a cooling agent for collectors of thermionic elements of the previous floor. The duty cycle is repeated until the temperature of the waste stream drops below the temperature of the thermal emission of electrons.

Thermionic elements are interconnected in a single electrical circuit.

In the known thermionic emission generator, each of the thermionic elements contains a flat emitter and a collector, which are placed with an interelectrode gap inside a flat sealed casing, and an electron transfer mechanism through the interelectrode gap (RF Patent No. 2144241, IPC Н01J 45/00, 2000).

The application of the method allows the use of heat that has passed through each thermionic element in subsequent thermionic elements, which ensures high efficiency of the conversion of thermal energy into electrical energy, increases the efficiency of the thermionic generator to 60%. The disadvantage of this method is that the thermionic generator made by the known method does not produce alternating current.

The objective of the invention is to provide high conversion efficiency in a thermionic generator of thermal energy to electrical energy of an alternating multiphase electric current and to improve the shape of the output voltage.

The problem is solved in that in a thermionic emission generator with thermionic elements placed in the form of a multi-storey battery, according to the claimed method, the phase shift, frequency and shape of the output voltage are set by a control circuit that generates discrete pulses with varying amplitude and duration equal to the duration of the interval between pulses . Pulses periodically include in the work of thermionic elements. In this case, the thermionic elements are combined into groups according to the number of phases, in each group the thermionic elements are connected in parallel chains, in one phase there is an even number and at least four, the chains in the phase are turned on in pairs.

In the pulsed operation of thermionic elements, the maximum effect of the conversion of heat into electrical energy is achieved (see, for example, Prince L.N.Dobretsov, M.V. Gomoyunova. "Emission Electronics", publishing house "Nauka", M., 1966, on page .205, in table 4 the last line).

Comparison of the proposed method with the known one allows us to conclude that the proposed method meets the criterion of "novelty", as a new method of organizing the flow of electric energy in a thermionic generator is proposed, in which direct high-efficiency conversion of heat into electrical energy of multiphase alternating current is carried out. The output voltage has a strictly sinusoidal shape. The shape of the output voltage is formed by the original continuous filling with high-frequency pulses of different amplitude. It becomes possible to widely vary the frequency of the output voltage.

In the known sources of information, no data were found on the popularity of the claimed method of controlling the thermionic emission elements for forming a sinusoidal envelope of the output voltage with the possibility of frequency regulation. All of the above allows us to conclude that the proposed solution meets the criterion of "Inventive step".

The inventive method can be applied at any power plant, as well as where it is necessary to control the frequency of the supply voltage without reducing the generated power during the consumption of electric energy, for example, in electric drives in transport.

The inventive method of direct conversion of heat into electrical energy of three-phase alternating current is illustrated by the following drawings.

Figure 1, a presents a diagram of the motion of the coolant flow through thermionic elements of a thermionic generator.

Figure 1, b shows a fragment of the device of a flat thermionic element.

Figure 2, a shows a block diagram of a thermionic generator, which implements the method.

Figure 2, b is a schematic diagram of the electrical connections of the thermionic generator, as an example of a specific implementation of the method.

Figure 2, in the form of the control and output voltages in the nodes of the thermionic generator.

The thermionic generator used to demonstrate the method (Fig. 1, a) consists of flat thermionic elements 2 placed on the floors in the housing 1. Each of the thermionic elements contains an emitter 3 and a collector 4 with an interelectrode gap and is placed inside a sealed enclosure.

Block 5, containing bypass channels, which serves to transfer the flow of coolant 6 (the path of the coolant is indicated by a solid line with arrows) from floor to floor, directly comes to housing 1. The coolant is hot gas (smoke) from burning fuel in the furnace of the thermionic emission generator (in Fig. 1, but the furnace is not shown). An intermittent line with arrows indicates the air flow 5, which is used to cool the collectors of the last floor (in Fig. 1, and the bottom).

Figure 1, b shows the placement of the emitter 3 and collector 4 in the thermionic element. Near the collector in the interelectrode space of the thermionic element there are wires 8 of the control grid with heat-resistant electrical insulation 9.

The block diagram of figure 2, and includes four sections. In section 1 (driver of control signals), electrical control signals are generated that provide phase shift, frequency and shape of the output voltage of the thermionic generator. In section 2, the continuous-waveform signals are converted to pulsed and the power of the pulsed signals is matched with the powers required to power the control grids of the thermionic elements of section 3. Section 3 (power) is used to generate electrical energy from thermal energy. Each thermionic element produces electric energy only during the period when a voltage pulse is applied to its grid from section 2. In section 4 (load), electricity is consumed.

The claimed effect in a thermionic generator is achieved through the methods of switching thermionic elements into a single electric circuit and the targeted influence of control pulse signals on the control grid of thermionic elements.

In the diagram of figure 2, b thickened lines show the connections of the elements of the power part of the thermionic generator, thin lines indicate the connections of the elements of the control circuits.

Thermionic elements (TE1, ..., TE4), as shown in the diagram of FIG. 2, b (section 3), are divided into three equal groups according to the number of phases required for feeding a load, which consumes a three-phase alternating current.

The diagram shows the connection of FCs of only one phase A, the connections of phases B and C are similar, therefore their images are not shown. Fuel cells in one phase are divided into 4 chains. The TE compound in each chain is sequential. All four chains are connected in parallel and counter-pairwise so that only one direction can follow through chains 1, 2, and in the opposite direction through chains 3, 4.

This method of connection in phases is due to the properties of TE. A fuel cell is a source of electricity; it converts heat to electricity. A fuel cell can only generate current in one direction. The voltage value of the FC is proportional to the voltage on the control grid, and the FC only works effectively when an intermittent unipolar voltage is applied to the grid, which has a positive polarity with respect to the emitter. When the control signal is zero or the signal of the opposite sign in the fuel cell does not generate electrical energy.

In each TE circuit, the control grids are interconnected and connected to the outputs of the power matching amplifiers UM1, ..., UM4, section 2. The load Z (section 4) is connected to the star at the output of the power circuit of the thermionic generator, it can also be connected to a triangle, if required. The system for generating control signals (sections 1 and 2) can be implemented on electromechanical elements or integrated circuits. A variant of the system of figure 2, b is made on electromechanical elements. The DC micromotor M is powered by a stabilized source B, which can be recharged from the power circuits of section 3 (in Fig. 2, b, the charging circuit is not shown). The potentiometer R controls the voltage of the micromotor M. The micromotor M rotates the microgenerator G, on the rotor of which a bipolar magnet rotates. On the stator G placed windings. Their spatial arrangement provides a constant phase shift of the emf induced in them. When the magnet rotates in the windings, an emf of a sinusoidal shape is induced. The frequency of the EMF is determined by the rotational speed of the rotor G. The revolutions of the micromotor M are proportional to the magnitude of the input voltage. When moving the potentiometer engine R, the revolutions of the micromotor M and, consequently, the frequency of the emf generated by the microgenerator G. will change. Thus, the control voltage signals of section 1 have a sinusoidal shape, a phase shift and a given frequency. By changing the magnitude of the recharge of permanent magnets in the generator G with a change in the speed of rotation of its rotor, stability of the amplitude of the output voltage of the generator is achieved. The recharge scheme of the magnets in figure 2, b is not shown. In the converting-matching device (section 2), a continuous signal is converted into pulses, and the pulse durations and gaps are the same, and the envelope amplitude of the pulses repeats the shape of the signals generated in section 1. In this case, the analog keys are used on the MOS transistors ( see book Tetelbaum IM, Schneider Yu.R. “Practice of analog modeling of dynamical systems.” Reference manual - M .: Energoatomizdat, 1987, p.241). Alternately, pulses appear on each of the two outputs of the TR trigger and open transistors VT1 and VT3 or VT2 and VT4. Opening transistors is accompanied by shorting the amplifiers 1 and 2 or 3 and 4, in this position the amplifiers do not pass the signals generated in section 1, and there will be a voltage of zero at their outputs. During the operation of the TR at the outputs of the amplifiers UM1, ..., UM4, discontinuous signals are formed in the form of a series of pulses with the appearance frequency set on the TR and amplitudes forming an envelope that repeats the waveform of section 1.

As follows from the voltage graphs U1 and U2, their shapes complement one another and, when superimposed, they form a continuous sinusoidal dependence. Their outputs UM1 and UM2 are connected to the grids of two different chains of thermionic elements TE1 and TE2. The control grids of the chains are under pulsed voltage, and therefore there is an intensive conversion of heat into electrical energy in these two chains. The maximum effect of the conversion is achieved by adjusting the frequency of the trigger TR. The voltage on the chain of TE1 and TE2 will not be pulsed, but filled due to the effect of pulsed signals alternately on each chain. This chain is “open” for current in one direction. When the sign of the signal changes, this chain closes, and the chain containing the thermionic elements TE3 and TE4 works. Amplifier P serves to reverse the sign of the signal. The dashes in FIG. 2, c indicate the pulses of the signals during the periods when they lock the chains. thermionic elements.

Claims (1)

A method for directly converting thermal energy into electrical energy by transferring heat to thermionic elements placed in a sealed housing of a thermionic generator in the form of a multistory battery through a flow of a heat carrier moving along a spiral path, characterized in that thermionic elements are combined into groups according to the number of phases, in each group thermionic elements are connected in parallel chains, at least four chains are set in one group, half of the chains are turned in the opposite direction, and the shift of phases, the frequency and shape of the output voltage of the thermionic generator is set by control pulses, which are supplied to the control grids of thermionic elements, the pulses have durations equal to the durations of the gaps, but differ in amplitudes, and pulses shifted in time by the value of the gap are supplied to the part of the chains of the same direction in relation to the pulses arriving at the grids of another part.

Images