RU2735021C1 - Sinusoidal voltage generator based on nuclear power plant - Google Patents

Abstract

FIELD: electrical engineering; nuclear power engineering.

SUBSTANCE: invention relates to electrical engineering and nuclear power engineering and is intended for generation of variable sinusoidal electromotive force by modules with series-parallel connection of electric generating elements (EGE), converting heat energy of nuclear power plant of spacecraft (SC) into direct current electric current. Frequency of generated voltage is set by clock generator of control unit and can be changed during operation of generator. Device can be divided into following functional units: control unit, which provides cyclic, with given period T alternate supply of control pulses, which control opening of electronic switches located in switching unit; switching unit, which provides connection to output terminals of switching unit of DC voltage sources generated by unit of power supply modules (ME); ME unit for n = 8, consisting of four power modules ME1…ME4 connected in series. Modules mid connection point is connected to generator output terminal. Remaining outputs of the modules are connected to controlled switches of the switching unit. Each ME module consists of series-parallel EGE connection.

EFFECT: technical result, which is achieved by claimed invention, consists in development of alternating voltage generator for supply of SC devices without using inverters and storage batteries or electric converters.

1 cl, 6 dwg, 3 tbl

Description

I. Field of the invention to which the invention relates

The invention relates to the field of electrical engineering and nuclear energy. The device is designed to generate a sinusoidal voltage using modules from power generating elements (EGE). Thermoelectric, thermoemission or thermoelectrochemical converters can be used as EGE, with the help of which the thermal energy generated by the nuclear power plant (NPP) is converted into electrical energy. In the described generator, obtaining a sinusoidal function of the output voltage of the device is based on the approximation of a sinusoidal function by a sequence of impulse functions, as described in [1].

II. State of the art

II.1 Comparison with prior art

In the power supply systems of spacecraft (SC), converters (inverters), including step-up transformers, or electric machine generators, are currently used to obtain high-voltage direct or alternating voltage. The high-voltage consumers of the spacecraft include electric propulsion engines (ERE). Table 1 shows the typical values of voltages and currents of various types of electric propulsion engines.

It follows from the table that the voltages required for the operation of the ERE can be tens of thousands of volts. The mass-dimensional characteristics of devices containing a step-up transformer on a ferromagnetic core or electric machine generators are large and range from γ = (3 ... 5) kg / kW to γ = 30 kg / kW. The characteristics of the step-up transformer used in the spacecraft power supply system are given in [2]. To convert thermal energy generated by a nuclear reactor into electrical energy, thermoelectric, thermo-electrochemical (TECG) and thermoemission converters are used. In such converters, electrical energy is generated by separate power generating elements (EGE). Each EGE generates DC electrical energy of a small voltage value, of the order of 1 V. To obtain the voltage and current of the required value, a series-parallel connection of the EGE is used. To obtain the required voltage value, a serial EGE connection is used, to obtain the required current value, a parallel EGE connection is used. To obtain the required voltage and current, individual EGEs are combined into modules. To obtain the required current value of the EGE module, they are connected in parallel; to obtain the required voltage value, individual EGEs, or groups with a parallel EGE connection, are connected in series. This is shown in FIG. 1. In the figure of FIG. 1 shows a parallel-serial connection of the EGE. A group of k parallel-connected EGEs with a current Ie provides the module current Im = k⋅Ie, a series connection of p such groups provides the module voltage Um = p⋅Ue. As a result, the module will have the parameters Um and Im.

Figure 1. Serial-parallel connection of EGE

The parameters of one TECG are given in Table 2, according to the data published in [1].

In total, in the thermo-electrochemical generator described in [1], 1344 EGE were required to obtain an electric power of 30 kW (or 90 kW at an increased frequency). Using the transformer described in [1], the voltage was increased from 120 V to 3000 V.

To improve the mass-dimensional characteristics of the spacecraft power supply system, it is advisable to obtain a high AC voltage using the proposed semiconductor generator. The generator described below makes it possible to obtain a high AC voltage as a result of combining individual EGEs into modules and switching modules to obtain the required values of alternating voltages and currents.

II. 2 Purpose of the invention.

The aim of the invention is to develop a device for generating sinusoidal alternating voltage using modules containing a series-parallel connection of EGE. In this case, the primary source of energy is the nuclear power plant. With the help of EGE, the thermal energy of the nuclear power plant is converted into electrical energy of constant voltage, which is then converted into electrical energy of alternating voltage. The conversion is carried out using pulse technology and switches on semiconductor devices. Due to the use of impulse technology and semiconductor switches, the mass-dimensional characteristics of the device increase.

II. 3. Inventive level.

The proposed device for generating alternating high-voltage sinusoidal voltage using nuclear power plant energy differs from devices in which alternating high-voltage sinusoidal voltage is obtained as a result of using inverters and step-up transformers, or with the help of electric machine generators [3, 4] in that:

- sinusoidal voltage is generated as a result of approximation of the sinusoidal function of the output voltage by a sequence of impulse functions;

- voltage pulse functions are generated by modules, each of which contains a series-parallel connection of EGE to obtain the required voltage and current of the module. Module voltage and current are equal to Um and Im;

- the number of impulse functions during the period of the sinusoidal function is set by the control unit. The voltage at the generator output is formed by a set of rectangular voltage pulses of a given value and the same duration TI, which are repeated at a given frequency. The number of pulses in the period T is equal to n = T / TI. The voltage value of each pulse is a multiple of the voltage value of one power supply (module);

- the amplitude values of the pulses are multiples of the module voltage. For example, if the voltage of the module is Um, then the amplitude of the first pulse is taken equal to E1 = Um, the amplitude of the second pulse is taken to be E2 = 2E1, E3 = -E1, E4 = -E2. Multiple values of pulse voltages are obtained as a result of serial connection of modules;

- series connection of sources of positive polarity and series connection of sources of negative polarity makes it possible to obtain multiple values of voltages of positive and negative polarity with respect to the voltage of one source, which are necessary for approximating sinusoidal voltage functions by a sequence of impulse functions;

- the number of power supplies (modules) is n / 2. Here n is the number of time intervals on the period of the sinusoidal function T, which approximate the sinusoidal function;

- the number of series-connected sources of positive polarity and the number of series-connected sources of negative polarity is equal to n / 4;

- For switching pulses, a switching unit is used, with the help of which pulse voltages of the required magnitude are connected to the output of the device in the sequence specified by the control unit.

III. Disclosure of the essence of the invention

III. 1 Approximation of a sinusoidal function by a sequence of impulse functions

In the figure of FIG. 2 shows the approximation of a sinusoidal function by a sequence of impulse functions, when the number of impulse functions on the period of the sinusoidal function T is equal to n = 8.

FIG. 2 Approximation of a sinusoidal function by a sequence of impulse functions for n = 8

FIG. 2 shows a segment of a sinusoidal function with an amplitude E _m in the interval 0..2π. The sinusoidal function in this interval is approximated by a sequence of n = 8 pulse functions with multiples of the pulse amplitudes. For the device shown in FIG. 2 approximations E1 = Um, E2 = 2E1, where E1 is the amplitude value of the first pulse, E2 is the amplitude value of the second pulse, Um is the voltage of one power generating module. To approximate the negative half-wave of a sinusoid, the amplitude is E3 = -E1, the amplitude is E4 = -E2.

Establishing the values of the pulse amplitudes for the case n = 8

In Table 3, in accordance with the figure in FIG. 2 recorded the values of the pulse amplitudes for each of 1 ... 8 intervals of approximation.

The values of the amplitudes of the pulses E ₁ , E ₂ , E3 and E4 are shown in the figure of FIG. 2.

III. 2. Block diagram of the device

The block diagram of the device is shown in Fig. 3.

Figure 3 Block diagram of the device

In the figure of FIG. 3 shows the following device blocks:

1. Control unit. Provides cyclic, with a given period T, alternate supply of control pulses that control the opening of electronic keys located in the switching unit;

2. The switching unit provides connection to the output terminals of the switching unit of voltage sources generated by the EGE module block.

3. Block of EGE modules. The block generates constant voltages of a given value of positive and negative polarity. The voltages of the sources are connected by keys located in the switching unit to the output terminals of the switching unit. Distinctive for the proposed device is that the voltages of positive and negative polarity are formed as a result of a series connection of the same voltage sources. EGE modules are used as power sources.

In the figure of FIG. 3 shows the block diagram of the device with the indication of the external poles of the blocks, with the help of which the blocks are connected and the device is controlled, and also the block numbering is shown in accordance with the general schematic diagram:

- B1 - control unit;

- B2 - switching unit;

- B3 - block of ME power supply modules;

In the figure of FIG. 3 shows the poles with which the interaction of the blocks is carried out and the poles 6 and 13, with the help of which the device is controlled. Pole numbers are indicated in accordance with the general circuit diagram of the device. The signal for starting the device is entered using pole 6. The number of time intervals n, into which the period of the sinusoidal function T is divided, is entered using pole 13. Using poles 8 ₁ ... 8 _n, the control unit and the switching unit are connected using poles 11 ₁ … 11 _{n / 2} the power supply is connected to the switching unit, using poles 10 ₁ … 10 ₂ an external load is connected to the device.

III. 3 Control unit

The control unit B1 is designed to generate control pulses as a result of creating a sequence of rectangular pulses of a given duration TI and supplying these signals to the control electrodes of the controlled keys 9 ₁ ... 9 ₄ located in the switching unit. The block forms a sequence of pulses cyclical with a period T. The value of T is equal to the period of the sinusoidal function. The number of pulses in the period T is equal to n, the duration of one pulse is TI. The values of n and TI are selected based on considerations of ensuring the required approximation error of a sinusoidal function by a sequence of rectangular impulse functions and the cost of implementing the device. With increasing n and decreasing TI, the error decreases and the cost increases.

With the help of electronic keys located in the switching unit, the EMF sources generated by the ME1 ... ME4 power supply module unit are connected at the times specified by the control unit in accordance with a given algorithm to the output poles of the switching unit. Switching is carried out in the open state of the key. The duration of the open state of each key is TI. The amplitudes of the EMF pulses for n = 8 are given in Table 3.

A schematic diagram of the control unit is shown in Fig. 5. The block is implemented on elements 1-7. It contains a clock pulse generator (GTI) 1, a logical element AND 2, a counter 3 of the number of pulses at a period T of a periodic function, a comparison circuit 4, a register 5, a decoder 7 with a number of outputs equal to n- the number of pulse functions at a period T. Starting work The device is supplied with a signal at input 6. At input 13, the code of the number of time intervals n is recorded.

The GTI output 1 is connected to the first input of the AND element 2, the second input of which is connected to the first input 6 of the device, and the output to the first input of the counter 3, the output of which is connected to the input of the decoder 7 and to the first input of the comparison circuit 4, the second input of which is connected to the output of register 5, and the output to the second input of the counter 3, the input of the register 5 is connected to the input 13 of the device, the outputs of the decoder 7 are connected to the inputs 8 ₁ ..8 _n , with the help of which the control unit is connected to the switching unit.

III. 4 Switching unit

Using the B2 switching unit, the voltage sources coming from the ME ₁ ME ₄ power supply modules are connected at the appropriate time intervals

(k-1) TI≤t≤kTI, k = 1, 2, ... n

to the output poles of the unit 10 ₁ ... 10 ₀ . In the written expression TI is the duration of the time interval of one voltage pulse, n is the number of time intervals in the period T. Switching is carried out using controlled electronic keys 9 ₁ ... 9 ₄ . The pulses that control the open state of each electronic key come from the control unit via poles 8 ₁ ... 8 _n . The first pulse from the control unit is supplied to the control electrode of the key 9 ₁ from the pole 8 ₁ through the diode D ₁ . The same control electrode receives a control pulse from pole 8 ₄ through diode D ₂ during the fourth control pulse. The control of switching on the remaining keys 9 ₂ … 9 _{4 is} carried out in the same way.

The schematic diagram of the switching unit is shown in Fig. 6. On the schematic diagram, the input poles, from which the control pulses to open the electronic keys are received, are poles 8 ₁ ... 8 ₈ . Poles 11 ₁ ... 11 _{4 are used} to connect voltage sources E ₁ ... E ₄ to the switching unit. In this case, the value of E ₁ is determined by the voltage of one power source (module ME1). As shown in FIG. 1, EMF of modules ME ₁ … ME ₄ are equal to voltage Um. In accordance with the diagram of FIG. 6 voltages taken from poles 11 ₁ ... 11 ₄ are equal

E ₁ = E = Um, E ₂ = 2E ₁ , E ₃ = -E ₁ , E ₄ = -E ₂ . Switching is carried out using controlled electronic keys. The schematic diagram shows keys 9 ₁ … 9 ₄ . The output poles are 10 ₁ and 10 ₂ .

III. 5 Block of power supply modules ME

The block of power supply modules (ME), block B3, is designed to power an alternating high-voltage voltage generator from modules consisting of series-parallel connected EGE power supply elements, as shown in the figure of FIG. 1. Each module is characterized by module voltage Um and module current Im. The power supply unit consists of four modules ME1 ... ME4, connected in series. The midpoint of the connection, located between the modules ME1 and ME3, is common for the entire device and is marked with a "ground" symbol. This pole is connected to the negative pole of the ME1 element and the positive pole of the ME3 element. The positive pole 11 _{1 of} the ME1 module has a voltage E1 equal to the voltage of the E1 module = Um. It is connected to the negative pole of the ME2 module. The positive pole of this module 11 ₂ will have a voltage with respect to "ground" E2 = 2E1 = 2 Um. The negative pole 11 ₃ of the ME3 element is connected to the positive pole of the ME4 element. It has a voltage of E3 = -E1 = -Um. The negative pole 11 ₄ of the ME4 element has a voltage relative to the "ground" equal to E4 = -2 Um. Poles 11 ₁ ... 11 _{4 the} power supply module is connected to the corresponding poles of the switching unit B2. The earth pole of the BZ block is connected to the 10 ₂ pole _of the B2 block.

IV. Brief Description of Drawings

FIG. 1 Series-parallel connection of EGE

FIG. 2 Approximation of a sinusoidal function by a sequence of impulse functions for n = 8

FIG. 3 Block diagram of the generator

FIG. 4 Schematic diagram of the control unit

FIG. 5 Schematic diagram of the switching unit for i = 8

FIG. 6 Schematic diagram of the ME block

V. Implementation of the invention

Description of device operation. In the initial state, the code of the number of time intervals n is written on register 5 at input 13. The period of the sinusoidal function T is divided into this number of intervals when the sinusoidal function is approximated by a sequence of impulse functions. Counter 3 stores a zero code (the reset input to zero on counter 3 is not shown in Fig. 5). The operation of the device begins after a start signal is applied to the input 6 of the logical element AND 2. After the start signal is supplied, the pulses from the output of the clock pulse generator 1 through the open element And 2 begin to enter the input of the counter 3. The code from the output of the counter 3 enters the input of the decoder 7. the output of the decoder appears a single signal only at one of its n outputs. A single signal at the i-th (i = 1 ... n) output of the decoder 7 is fed to the input of the switching unit through one of the poles 8 _i , i = 1 ... n, which is connected to the control electrodes of the controlled keys 9 ₁ ... 9 ₄ . The inputs of the controlled keys are connected by poles 11 _i , i = 1..n / 2, to the voltage sources E ₁ ..E _n / 2, and the outputs of the keys are connected to the output poles of the switching unit 10 ₁ ..10 ₂ . In each time slot to each output pole switching unit 10 ₁ ..10 ₂ connects only one source of DC voltage of a set E ₁ ..E _{n / 2.} The source voltage values are equal to E ₁ = E = Um, E ₂ = 2E, E ₃ = -E ₁ , E ₄ = -2E. 5 shows the switching for the EMF generator, when the number of time intervals in the period T is equal to n = 8. According to the table. 3, in the first and fourth time intervals, the EMF source E ₁ = E is connected to the pole 10 ₁ , the pole 10 _{2 is} connected to the "earth" pole. In the second and third time intervals, the EMF source E ₂ = 2E is connected to the pole 10 ₁ , the EMF source E ₂ = 2E, in the fifth and eighth time intervals, the EMF source E ₃ = -E is connected to the pole 10 ₁ , in the sixth and seventh time intervals to to pole 10 ₁ an EMF source is connected E ₄ = -2E,

Connection of power supplies with voltages E ₁ ..E _{n / 2} to the output poles of the switching unit 10 ₁ ..10 is carried out using controlled electronic keys 9 ₁ ... 9 ₄ .. Signals that control the open state of the key at the time TI = T / n , come from the output of the decoder of the control unit by means of poles 8 ₁ ..8 _n . The control unit sets the sequence of the control pulses. The control pulse from the pulse shaper 8 _j , j = 1..n is followed by the control pulse from the pulse shaper 8 _{j + 1} until j + 1 becomes equal to n. After the end of the pulse from output 8 _n, pulse 8 _{1 is} turned _on . In this case, the current value of the counter of the number of pulses 3 coincides with the number n set by input 13, the counter is reset to zero and the process is repeated.

Vi. Literature

1. Gavrilov L.P. Generator of a polyphase EMF system for mobile devices Patent 2671539 dated 01.11.2018

2. Sinyavsky V.V. Scientific and technical groundwork for the nuclear electric missile MB "HERCULES" // SPACE EQUIPMENT AND TECHNOLOGIES №3 / 2013

3. Smirnov I.A., Morozov V.I., Deryagin Yu.A., Serednikov M.N., Dubovitsky A.V. Space power plant with machine energy conversion Patent RU 586797 C1 Published: 2016.06.10

4. Morozov V.I., Serednikov M.N., Negretsky B.F. Power plant with machine energy conversion Patent RU 2716766 Published: 2020.03.16

Claims (1)

A sinusoidal voltage generator based on a nuclear power plant (NPP), containing a control unit (B1), which consists of a clock pulse generator (GTI) (1), element I (2), counter (3), comparison circuit (4), register (5), start buttons (6), decoder (7), device input (13), GTI output (1) is connected to the first input of the I element (2), the start button (6) is connected to the second input of the I element (2) , the output of the AND element (2) is connected to the first input of the counter (3), the output of which is connected to the input of the decoder (7) and to the first input of the comparison circuit (4), the output of the comparison circuit (4) is connected to the second input of the counter (3), a register (5) is connected to the second input of the comparison circuit (4), at the input (13) of which the number of time intervals n is entered in the period T, the i-th output (i = 1, ..., n) of the decoder (7) is connected to i- th input (8i) (i = 1, ..., n), characterized in that the switching unit (B2) is connected to the control unit (B1) by the poles 8 ₁ ..8 _n , generated by the control unit rectangle pulses from the poles (8 ₁ ..8 _n ) are fed to the control electrodes of the semiconductor switches (9 ₁ ... 9 ₄ ) of the switching unit by means of diodes (D1… D8), by the poles (11 ₁ … 11 ₄ ) the switching unit is connected to the unit (B3 ), consisting of power supply modules (ME1 ... ME4), the voltage source (E ₁ ) of the B3 unit for the duration of the pulse TI is connected via the pole (11 ₁ ) to the controlled key (9 ₁ ), and when the key is open, the source voltage (E ₁ ) is transmitted to the pole (10 ₁ ), which is the output for the entire device, the voltage source (E ₂ ) through the pole (11 ₂ ) is connected to the controlled key (9 ₂ ), and when the key is open, the voltage is transmitted to the pole (10 ₁ ), the voltage source (E ₃ ) is connected to the controlled key (9 ₃ ), and when the key is open, the voltage is transmitted to the pole (10 ₁ ), the voltage source (E ₄ ) is connected to the controlled key (9 ₄ ), and when the key is open, the voltage is transmitted to pole (10 ₁ ), pole "earth" of the block ( B3) is connected to the pole (10 ₂ ) of the switching unit (B2), this pole is the output for the entire device, the sequence of pulses formed by the switching unit (B2) approximates the sinusoidal function of the output voltage, while the sequence of pulses is set by the control unit, voltages E1, E2, E3, E4, forming a sinusoidal function, are created by the unit (B3) as a result of using the voltages of the modules ME1, ME2, ME3, ME4, the voltages of which are formed from the voltage of power generating elements as a result of the transformation of thermal energy of the nuclear power plant into electrical energy by these elements.

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