RU2636053C2 - Method of generation of ac voltages of two different frequencies in three-phase current turbo-generator - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: additional set of three-phase windings is introduced into the turbo-generator, one of the windings is located in the common grooves of the stator, and the other - on the additional part of the non-salient pole rotor. The latter through the contact rings and brushes is connected to an adjustable reversible frequency converter, which provides an asynchronous mode with a negative slip frequency in the turbo-generator. In order to exclude the mutual electromagnetic influence of the main and additional three-phase windings located both in the stator grooves and on both parts of the rotor, their numbers of pairs of poles are selected under the condition p₁>p₂. Generation in an additional winding of the electrical power of three-phase current of industrial frequency (50 Hz) at a turbo-generator's rotation frequency n₁=6000 rpm simultaneously with generation of three-phase current of increased frequency (200 Hz) in the main winding of the stator of the turbo-generator.

EFFECT: generation of voltages of two different frequencies.

2 cl, 1 dwg

Description

1.1. The field of technology.

The invention relates to the field of electrical engineering, in particular, to electric synchronous generators of alternating three-phase current with electromagnetic excitation and with additional windings on the stator and on the rotor to generate voltages of two different frequencies.

1.2. The level of technology.

A known method of generating an alternating voltage used in a synchronous turbogenerator with electromagnetic excitation, consisting of a charged magnetic core (stator) with a cylindrical bore and grooves on its inner surface, in which a distributed winding of an alternating three-phase current is placed, and a ferromagnetic rotor located inside the stator bore and mounted on the shaft, resting its ends on bearings, one of the ends of which is connected to a drive motor (turbine) [1].

In the grooves of the ferromagnetic rotor of an implicit design, a direct current excitation winding is placed, which in turn is electrically connected to a rotating rectifier of a brushless excitation device [2], rigidly fixed to the shaft end. The DC excitation winding is powered by the electric power of the brushless excitation device when the rotor rotates from the drive motor.

In the indicated turbogenerator, when the rotor rotates as a result of the interaction of the magnetic field of the rotating direct current excitation winding with the stator winding, an alternating three-phase electromotive force (emf) is induced in it, which should later be synchronized in magnitude, frequency and phase when connected to an external network with external voltage.

The magnitude of the first (main) harmonic of the emf with E ₁ and its frequency in the general case is determined by the formulas:

Where:

- W is the number of turns in the phase of the stator winding;

- F ₁ - the first harmonic flux linkage phase of the stator winding, WB;

- k _{vol. 1} - winding coefficient;

- k _{c. 1} is the bevel coefficient of the grooves;

- частота переменной э.д.с, Гц;-

- frequency of the variable emf, Hz;

- p ₁ - the number of pairs of poles of the stator winding and rotor;

- n ₁ - rotor speed, rpm

In accordance with formula (2), to obtain an alternating three-phase voltage of an industrial frequency of 50 Hz, the maximum possible rotational speed of the rotor n _{1 of a} synchronous turbogenerator with p ₁ = 1 is n ₁ = 3000 rpm [1].

It is known that steam (gas) turbines, which are the driving engines for the turbogenerator, have the best technical and economic indicators (efficiency, specific power, etc.) at higher rotational speeds n≥6000 rpm [3].

The disadvantage of this technical solution of a turbogenerator of alternating voltage of an industrial frequency of 50 Hz is that an intermediate mechanical gearbox is used for its drive [3], which leads to an increase in the mass, dimensions and cost of the entire turbine unit as a whole.

A known method of generating alternating voltages, implemented by the technical solution described in [4], according to which the three-phase current of increased frequency (200 Hz and more) is generated by the main turbogenerator as part of the ship’s electric power system (EPS), the rotation of which is performed directly from the turbine at a frequency rotation n≥6000 rpm (analog).

The disadvantage of this technical solution of the main turbogenerator of increased frequency is that for supplying general ship consumers as part of the EPS [4] with a three-phase current of industrial frequency of 50 Hz, the necessary converting devices with a capacity equal to the sum of the total capacities of the said consumers taking into account their possible overloads are used.

Another close in technical essence to the claimed method is a method used in an electric machine frequency converter with a phase rotor [1], in which when the rotor rotates from a drive motor, incl. at a higher rotational speed, and when a three-phase voltage of one frequency is applied from the rotor side, a three-phase voltage of another frequency can be obtained from the stator side, incl. industrial frequency 50 Hz.

The closest in technical essence is the method of controlling an autonomous asynchronous generator [5] (prototype), in the circuit of a three-phase winding of the rotor of which an adjustable frequency converter is used. When changing, for example, with an increase in the speed of the drive motor, the frequency and amplitude of the induced emf remain constant in a three-phase stator winding, they are supported by appropriate regulation of the frequency and amplitude of the three-phase current at the output of said frequency converter.

However, in this prototype there is no possibility of generating alternating voltages of two different frequencies.

The objective of the proposed technical solution is to expand the functionality of a three-phase current turbogenerator.

The technical result of the proposed technical solution consists in the fact that when using the proposed method in a three-phase current turbogenerator at a higher rotation speed n ₁ = 6000 rpm, along with the generation of electric power of a three-phase current of an increased frequency of 200 Hz, a three-phase current of industrial frequency 50 is generated simultaneously Hz

основной волны намагничивающей силы трехфазной обмотки возбуждения, размещенной в пазах дополнительной части ротора, поддерживают в противоположном направлении всегда ниже угловой частоты вращения

ротора, что позволяет при более высокой частоте вращения расширить функциональные возможности турбогенератора трехфазного тока.The specified technical result is achieved by the fact that in the inventive method of generating alternating voltages of two different frequencies in a three-phase current turbogenerator containing a ferromagnetic charged stator with a cylindrical bore, on the inner surface of which two distributed three-phase windings are placed - the main and additional - with the number of pole pairs, respectively p ₁ and p _2, and a rotating ferromagnetic rotor (main part) neyavnopolyusnoy cylindrical structure disposed within the stator bore, and the outer surface of which in the grooves placed DC field winding with the number of pairs of poles p _1, connected to the output device of the brushless excitation provides the following differences - in neyavnopolyusnuyu structure ferromagnetic rotor administered additional part with located in its slots of a three-phase excitation winding with a number of pairs of poles p ₂ connected through contact rings and brushes to a three-phase output of a reversible frequency converter, and the number of pairs of poles of both windings placed as on stat the nut, and on the rotor, are selected subject to the conditions p ₁ > p ₂ , as well as the angular frequency of rotation

the main wave of the magnetizing force of the three-phase field winding, located in the grooves of the additional part of the rotor, is supported in the opposite direction always below the angular frequency of rotation

the rotor, which allows for a higher rotational speed to expand the functionality of a three-phase current turbogenerator.

1.3. A brief description of the drawings.

The proposed method is illustrated in the drawing, which shows a block diagram (Fig. 1) of the construction of a three-phase current turbogenerator that implements the proposed method for generating alternating voltages of two different frequencies.

In the presented block diagram (Fig. 1), the following notation is used:

1 - stator;

1.1 - the main three-phase winding;

1.2 - additional three-phase winding;

2 - transformer;

3 - switch;

4 - reversible frequency converter;

4.1 - three-phase input;

4.2 - three-phase output;

5 - switch;

6 - external network of increased frequency;

7 - switch

8 - external network of industrial frequency;

9 - the main part of the rotor;

10 - an additional part of the rotor;

11 - drive engine (turbine);

12 - field winding;

13 - three-phase field winding;

14 - brushless excitation device.

1.4. Disclosure of the invention.

The proposed method consists in the fact that in the implicit pole design of the ferromagnetic rotor located inside the stator bore, an additional part is introduced with a three-phase field winding located in its grooves, and an additional three-phase winding on the stator is introduced, the number of pole pairs of which differs from the number of pole pairs of the main windings located on the stator and on the main part of the rotor. Moreover, a reversible frequency converter (HRE) is connected to a three-phase winding circuit located on an additional part of the rotor.

The three-phase current turbogenerator has a ferromagnetic laminating stator 1 with a cylindrical bore and grooves on its inner surface, in which, along with the main three-phase winding 1.1 of increased frequency voltage, an additional three-phase winding 1.2 of industrial frequency voltage is distributed in the common grooves (Fig. 1).

и имеющую число пар полюсов р₁=2, соединяют через согласующий трансформатор 2 и выключатель 3 с трехфазным входом 4.1 обратимого преобразователя частоты 4, а также через выключатель 5 соединяют с внешней сетью 6 повышенной частоты.The main winding 1.1, designed to generate an alternating three-phase voltage, including high voltage, high frequency

and having a pole pair number p 2 = _1, is connected through a matching transformer 2 and the switch 3 with three-phase input 4.1 reversible frequency converter 4 as well as through the switch 5 is connected to the external network 6 increased frequency.

и имеющую число пар полюсов р₂=1, соединяют через выключатель 7 с внешней сетью 8 промышленной частоты 50 Гц.An additional three-phase winding 1.2, designed to generate an alternating three-phase voltage of industrial frequency

and having the number of pole pairs p ₂ = 1, connect through a switch 7 with an external network 8 of industrial frequency 50 Hz.

Inside the stator bore 1, there is a cylindrical rotor made of ferromagnetic material, consisting of the main 9 and an additional 10 parts of the rotor of an implicit pole mounted on a common shaft, resting its ends on bearings (not shown in the figure), one of the ends of which is connected directly to the drive motor (turbine) 11.

On the outer surface of each part of the rotor there are grooves. In the grooves of the main part of the rotor 9 of the implicit pole design, a distributed DC excitation winding 12 with the number of pole pairs p ₁ = 2 is placed, and in the grooves of the additional part of the rotor 10 of the (charged) implicit pole design, the distributed three-phase excitation winding 13 with the number of pole pairs p ₂ = 1 is placed .

The DC winding 12 is electrically connected to the output of the brushless excitation device 14 located at one end of the shaft. The three-phase field winding 13 is electrically connected to three contact rings located and rigidly fixed at the other end of the shaft (not shown in the figure).

выходного тока.The contact rings by means of three fixed electric brushes (not shown in the figure) are phase-connected to the three-phase output 4.2 of a reversible frequency converter 4, with the ability to control the amplitude and frequency

output current.

The three-phase current turbogenerator according to the proposed method for generating alternating voltages of two different frequencies works as follows.

и осуществляют подключение цепи электропитания обмотки возбуждения 12 постоянного тока к устройству бесщеточного возбуждения 14.Pre-driven engine (turbine) 11 start and accelerate the turbogenerator to a speed

and connect the power supply circuit of the excitation winding 12 direct current to the brushless excitation device 14.

которое через согласующий трансформатор 2 и выключатель 3 поступает на трехфазный вход 4.1 обратимого преобразователя частоты 4.As a result of the interaction of the magnetic field of the rotating direct current winding 12 of the direct current with the main winding 1.1 of the stator 1, the latter produces an alternating three-phase voltage of increased frequency

which through the matching transformer 2 and the switch 3 enters the three-phase input 4.1 of a reversible frequency converter 4.

в трехфазное напряжение промышленной частоты

которое при плавном увеличении его амплитуды и частоты от нуля до номинального значения

через трехфазный выход 4.2, электрические щетки и контактные кольца поступает в трехфазную обмотку возбуждения 13 дополнительной части ротора 10.Reversible frequency converter 4 converts an alternating three-phase voltage of high frequency

into three-phase voltage of industrial frequency

which, with a smooth increase in its amplitude and frequency from zero to a nominal value

through a three-phase output 4.2, electric brushes and slip rings enters the three-phase field winding 13 of the additional part of the rotor 10.

основной волны намагничивающих сил направлена в противоположную сторону относительно направления вращения ротора

по формуле (2).Next, the magnetizing currents arising in the three-phase excitation winding 13 create a spatial main wave (harmonic) of the magnetizing forces on the surface of the additional part of the rotor 10. Moreover, the phase sequence in the three-phase excitation winding 13 is chosen the same as in the prototype method, i.e. . such that the angular speed

the main wave of magnetizing forces is directed in the opposite direction relative to the direction of rotation of the rotor

by the formula (2).

скольжения, при котором угловую частоту вращения

основной волны намагничивающих сил трехфазной обмотки возбуждения 13 поддерживают всегда ниже угловой частоты вращения

ротора.Moreover, in the claimed technical solution, in contrast to the prototype, use the asynchronous mode of the turbogenerator with a negative frequency

slip at which the angular frequency of rotation

the main wave of the magnetizing forces of the three-phase field winding 13 is always kept below the angular frequency of rotation

rotor.

In order to exclude mutual electromagnetic influence caused by the action in the common ferromagnetic stator 1 of the main waves of the magnetizing forces of both windings 1.1; 1.2, located both on the stator and on both parts of the rotor 12; 13, select their number of pole pairs in compliance with the condition p ₁ > p ₂ . Thus, the resulting inductive three-phase emfs mutual induction in each of the windings from the action of three-phase currents of another winding located either on a common ferromagnetic stator 1, or on the main 9 or additional 10 part of the rotor, are equal to zero.

As a result of the interaction of the total magnetic field from two rotating field windings 12 and 13 with the main 1.1 and additional 1.2 stator windings 1, three-phase variable emfs are induced in them rotation:

- в основной обмотке 1.1;- with frequency

- in the main winding 1.1;

- в дополнительной обмотке 1.2 (знак - минус характеризует передачу энергии в сеть).- with slip frequency

- in an additional winding 1.2 (a minus sign characterizes the transfer of energy to the network).

через выключатели 5; 7 после их синхронизации по частоте и напряжению поступает во внешние сети 6; 8 переменного напряжения соответствующей частоты.Then, the generated electricity in said windings 1.1; 1.2 stator 1 in the form of three-phase currents of two different frequencies

through switches 5; 7 after their synchronization in frequency and voltage enters the external network 6; 8 AC voltage of the corresponding frequency.

скольжения в трехфазной обмотке возбуждения 13, расположенной на дополнительной части ротора 10, индуктируется переменная противо-э.д.с. с частотой

Под действием этой противо-э.д.с. электроэнергия трехфазных токов через контактные кольца и щетки поступает на трехфазный выход 4.2 обратимого преобразователя частоты 4.In addition, during the start-up and acceleration of the turbogenerator to the angular frequency of rotation ω ₁ and after putting it into asynchronous mode with a negative frequency

slip in the three-phase field winding 13, located on the additional part of the rotor 10, a variable counter-emf is induced. with frequency

Under the influence of this counter-emf. the electric power of three-phase currents through the contact rings and brushes is supplied to the three-phase output 4.2 of a reversible frequency converter 4.

поступает на трехфазный вход 4.1 ОПЧ 4 и через выключатель 3, согласующий трансформатор 2 и выключатель 5 после синхронизации по частоте и напряжению передается во внешнюю сеть 6 повышенной частоты

The specified electricity after the reverse conversion into a three-phase current with a frequency

enters the three-phase input 4.1 HRE 4 and through the switch 3, the matching transformer 2 and the switch 5 after synchronization in frequency and voltage is transmitted to the external network 6 high frequency

- в основной обмотке статора и генерацию трехфазных напряжений промышленной частоты

- в дополнительной обмотке статора.Thus, the proposed method for generating alternating voltages of two different frequencies in a three-phase current turbogenerator provides at the rotor speed n ₁ = 6000 rpm the claimed technical result, namely: generating three-phase voltages of increased frequency

- in the main stator winding and the generation of three-phase voltages of industrial frequency

- in the additional stator winding.

Literature.

1. Voldek A.I. Electric cars. M .: Energy, 1978, - p. from. 366; 375; 593; 430; 619.

2. Yakovlev G.S. Ship electric power systems. L .: Shipbuilding, 1987, - p. 61.

3. Block turbogenerators of the TG type. Products of OJSC Kaluga Turbine Plant; internet: www.oaoktz.ru.

4. Ship electric power system of alternating voltage of increased frequency with an electric propulsion system and matrix frequency converters. Aleksandrov V.P., Skvortsov B.A., Hamster V.A. RF patent No. RU 2510781 C2, class. H02J 3/34 dated July 17, 2012.

5. A method for controlling an autonomous asynchronous generator. Meshcheryakov V.N., Ivanov A.B., Kulikov A.I. RF patent 2213409, cl. Н02Р 9/00 dated 04/26/2001.

Claims (2)

1. A three-phase current turbogenerator of two different frequencies, containing a ferromagnetic charge stator with a cylindrical bore, on the inner surface of which two distributed three-phase windings are placed in the grooves - the main and additional with the number of pole pairs, respectively, p ₁ and p ₂ , and a rotating ferromagnetic rotor (main part ) of a cylindrical implicit pole design located inside the stator bore, on the outer surface of which a DC current winding with the number of pole pairs is placed in the grooves _1, connected to the output driving device, characterized in that the applied brushless excitation device; an additional part is introduced into the implicit pole design of the ferromagnetic rotor with a three-phase field winding located in its grooves with the number of pole pairs p ₂ connected through contact rings and brushes to the three-phase output of the reversible frequency converter, the number of pole pairs of both windings placed both on the stator and on the rotor, selected subject to the condition p ₁ > p ₂ . 2. A three-phase current turbogenerator of two different frequencies according to claim 1, characterized in that the angular frequency of rotation ω ₂ = 2πƒ ₂ / p _{2 of the} main wave of the magnetizing force of the three-phase field winding, located in the grooves of the additional part of the rotor, is always kept in the opposite direction below the angular rotational speeds ω ₁ = 2πƒ ₁ / p _{1 of the} rotor.

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