RU2658636C1 - Induction generator with combined excitation and stator windings - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: invention relates to the field of electrical engineering, namely to synchronous reactive electric generators with radial excitation. Inductor generator with the combined windings contains a stator with an apparent pole core and a multiphase winding made in the form of tooth coils covering the stator poles, excitation current sources made in the form of additional turns or additional coils placed together with the spools at the poles of the stator, and an uncoated rotor with a serrated core. Coils of each phase are interconnected and form windings of phases that are connected in a triangle or polygon scheme, and each of them consistently includes diodes connected in parallel to the capacitors. Sources of excitation current through thyristors, additional diodes or series-connected additional diodes and transistor wrenches are connected to diodes included in phase windings. Output voltage of the generator is controlled by controlling these thyristors or transistor switches.

EFFECT: invention makes it possible to increase the reliability and efficiency of the inductor generator, as well as to reduce its overall dimensions and mass.

13 cl, 6 dwg

Description

The invention relates to the field of electrical engineering, namely to synchronous reactive electric generators with radial excitation, used, in particular, in transmissions of tracked and wheeled self-propelled vehicles.

A known inductor generator with combined field windings and a stator (armature), comprising a gearless winding rotor and a stator, Z ₁ teeth of which are covered by stator winding coils (armature) forming an N-phase system. The stator winding is made with a tooth pitch and consists of Z ₁ coils, and each phase consists of Z ₁ / N coils located on opposite teeth. The coils of each phase are connected to each other in series or in parallel and connected to an electronic switch, which is usually implemented on power bipolar transistors with an insulated gate (IGBT) (English IGBT - Insulated-gate bipolar transistor) and diodes connected according to the scheme of the asymmetric bridge (KR 101311378 B1, Н02Р 9/26, 09/25/2013; US 5493195 A, Н02Р 9/04, Н02Р 9/08, 02.20.1996; CN 204408232 U, Н02Р 103/20, Н02Р 9/00, 06/17/2015) .

The excitation current in this generator is formed by connecting its output voltage to the phase windings using IGBT transistors of the electronic switch, and the on and off times are synchronized with the rotation of the shaft. Accordingly, IGBT transistors have a high operating voltage, which leads to an increase in static and dynamic losses in these transistors and, accordingly, to a decrease in the generator efficiency. The high operating voltage of IGBT transistors, combined with the increased complexity of an electronic switch containing 2⋅N power switches (IGBT transistors), reduce the reliability of the generator.

Also known is a three-phase multi-pole valve inductor generator containing a gearless non-winding rotor and a stator, on the teeth of the core of which are placed three-phase winding coils connected in a triangle. Diodes are connected in series with the phases, so that the winding combines the functions of the anchor (stator) winding and the excitation winding. In this case, the excitation voltage is supplied to one of the diodes (UA 98261 C2, H02K 19/16, 04/25/2012; Lushchik VD Ventilator induction radial excitation generators with summable windings. // Electrotechnics i Electromechanics. - Kharkiv: NTU "Kharkivskyi Institute ”, 2014, No. 6. - S.47-49).

This induction generator uses a separate excitation voltage source, which receives power from an external energy source or from the output voltage of the generator itself. Its output is galvanically connected to the stator winding. This leads to the need to use a galvanically isolated source of excitation voltage, providing the necessary (full) excitation power. Such voltage sources are implemented in the form of rather complex pulse voltage converters with a transformer output having increased overall dimensions and weight and limited efficiency. In addition, the currents flowing in the components of such a source (with the exception of the output current) do not lead to an increase in the excitation flux of the inductor generator. In this multiphase generator, the excitation voltage source is connected to a diode of only one phase, which leads to an asymmetry of this generator and, accordingly, to a deterioration in its efficiency and overall dimensions.

As a result, the disadvantages of the known inductor generator include its increased complexity and, accordingly, reduced reliability, as well as relatively low efficiency, increased overall dimensions and weight.

The problem solved by the invention is to increase the reliability and efficiency of the inductor generator, as well as reducing its overall dimensions and mass.

This technical result is achieved due to the fact that the inductor generator with combined field windings and the stator contains a fixed stator with an explicit pole core and a multiphase winding made in the form of gear coils covering the stator poles, at least one excitation current source made in the form of additional turns placed in the tooth coils, or in the form of one or more additional coils placed together with the tooth coils at the poles of the stator and interconnected by exploratory and / or parallel, a rotating windingless rotor with a toothed core fixed to its shaft, the stator and rotor cores being made in the form of packets drawn from insulated sheets of electrical steel, the stator poles and the rotor core teeth facing each other and separated by an air gap, and the gear coils of each phase are connected together in series and / or in parallel and form phase windings. In addition, the generator contains at least one diode connected in series in at least one of the phase windings, which are connected according to a triangle or polygon circuit, at least one capacitor, each source of excitation current through an additional diode, or through an additional diode connected in series the diode and the key, either through a thyristor is connected to the diode, and the capacitor is connected either parallel to this diode, or between the point of its connection with the phase winding and the point of connection of the key with an additional diode.

The implementation of the distinctive features of the independent claim provides the achievement of these technical results.

In particular, the implementation of the excitation current sources in the form of additional stator coils, or additional turns in these coils, and their connection via thyristors, an additional diode, or an additional diode and a key connected in series to a diode and capacitor connected in series in the phase windings, provides, in comparison with the prototype, increasing the efficiency of the inductor generator by eliminating energy losses in the switching power supply and its output transformer, providing galvanic isolation of the source the excitation voltage from the phase windings, and also due to the fact that the current in the additional windings, which serve as the excitation current source, is directed in the same direction as the excitation current in the generator phases. The use of capacitors in the excitation circuits, which create phase magnetic windings with an additional magnetic flux in the necessary positions of the stator poles (teeth) relative to the rotor teeth, leads to an additional increase in efficiency.

Thanks to these distinguishing features, it is also possible to increase the reliability of the inductor generator by simplifying the excitation voltage (current) source, including by eliminating the need for high-voltage devices for galvanic isolation of the excitation current source and phase windings, as well as by eliminating the connecting wires between the excitation current source and generator.

At the same time, due to the elimination of the need to use a separate pulsed excitation voltage source with galvanic isolation, including its transformer having large overall dimensions and mass, a decrease in overall dimensions and mass of the inductor generator is achieved.

In FIG. 1, an example is a three-phase inductor generator with combined field and stator windings having 12 stator poles and 8 rotor teeth. In FIG. 2 shows a five-phase version of an inductor generator. In FIG. 3, 4, 5 and 6 show one phase of the generator with various options for connecting the excitation current source to a diode connected in series in this phase.

In this case, an induction generator means a synchronous generator, in which the fixed stator acts as an armature and inductor, and the process of converting the mechanical energy of a rotating rotor into electrical energy is caused by pulsations of magnetic induction due to the gearing of the rotor.

This generator can also be called an inductor reactive generator, an inductor generator with radial excitation, an inductor bipolar generator, a valve inductor generator, etc., and in the English literature it can be called a generator with variable magnetic resistance: Switched Reluctance Generator (SRG).

An inductor generator with combined field and stator windings (hereinafter referred to as “generator” or “inductor generator”) contains a housing (bed) and bearing shields (not shown conditionally in the drawings). A stationary stator with a clearly polar core and an N-phase winding, made in the form of gear coils 1, covering each pole of the stator, as well as a rotating windingless rotor 2 with a toothed core 3, mounted on its shaft 4, are placed inside the housing (bed).

The stator and rotor cores are made in the form of packets drawn from insulated sheets of electrical steel. The stator poles and the teeth of the rotor core 3 are facing each other and are separated by an air gap.

In the induction generator, designed to work with low rotor speeds, the tooth zone of the pole zone, in order to increase efficiency and improve the overall dimensions of the generator, can be made comb.

On one, on two opposite, on all poles of the stator, related to each phase, or on all poles of the stator (Z ₁ ) there are additional coils 5, which are used as one or several (from one to N) sources of N-phase excitation current inductor generator.

Instead of additional coils, additional coils located in or next to the stator tooth coils can also be used.

The excitation current source may contain two additional coils (turns) 5. In this case, these coils (turns) are placed at opposite poles of the stator and are connected to each other in series or in parallel (Fig. 1). If the generator contains Z ₁ / N or Z ₁ additional coils (turns) used as one or more (≤N) sources of excitation current, then they are also connected to each other in series and / or in parallel. For example, if N = 3, Z ₁ = 12, then four additional coils (Z ₁ / N = 4) located at the poles of the stator, or additional turns placed in these coils related to the same phase, can be interconnected in series or in parallel, or two additional coils in series, and the resulting pairs in parallel.

Phase windings (phase windings) of the generator can be formed using similar options for the connections of its gear coils. For example, every two coils located on opposite poles (teeth) of each phase are connected in series in the opposite direction, and the pair of coils formed in parallel. It is also possible the formation of phase windings by parallel connection of all coils of one phase (Fig. 1).

These windings are simultaneously used as field windings, i.e. combined with field windings. For this, the generator magnetic circuit is designed in such a way that the field coil and the coil of the armature winding (it is also a stator) can be placed on the same stator teeth. In addition, the field winding is matched with the N-phase winding of the armature (stator).

To be able to pass the excitation current through the stator winding (armature), its phase windings are connected according to a triangle (Fig. 1, outputs of phases A, B, C) or a polygon (Fig. 2, outputs of phases A, B, C, D, E), and diode 6 is connected in series with one of the phase windings of the phases, or such diodes are connected in series with the windings of all phase windings.

The current of the excitation source is supplied to at least one diode 6 in one phase winding. This current, due to the indicated connection of the phase windings, flows through all these windings (along the entire contour of the N-gon).

In order to improve the characteristics of the generator, including to reduce the ripple of its output voltage, a symmetric scheme of its excitation can be applied. In this case, N excitation current sources are used, which are connected to the N main diodes 6 connected in series with the windings of all N phases, as shown in FIG. 1 and 2.

In parallel to the diodes 6, capacitors 7 are connected, which generate the reactive energy necessary for the operation of the inductor generator in the excitation mode from its own current sources - from additional windings (turns) 5, i.e. when it is operating in self-excitation mode.

Since a constant or unipolar pulse current is required to excite the generator, additional coils 5, used as one or several sources of excitation current, are connected directly to the diodes 6 and capacitors 7, but via additional diodes 8, if the generator does not provide for regulation of its output voltage (Fig. 3). If such regulation is provided, then the excitation current sources are connected to the diodes 6 through thyristors 9 (Fig. 2, 4) or through additional diodes 8 and switches 10 connected in series, made, for example, in the form of one or a group of parallel connected field-effect transistors with an insulated gate 11 (MOS - metal-oxide-semiconductor or MIS - metal-dielectric-semiconductor), and in English terminology - MOS, MOSFET or MOSFET (from the abbreviation of phrases: "Metal-Oxide-Semiconductor" (metal-oxide-semiconductor) and " Field-Effect-Transistors "(Transization OP controlled by an electric field) and their transcription (FIGS. 5, 6), or insulated-gate bipolar transistors (IGBT) (IGBT - Insulated-gate bipolar transistor), or bipolar transistors (BT) (BJT - Bipolar Junction Transistor.) Their crystals are housed in separate housings or combined into transistor modules.

Capacitors 7 can be of any type. It is advisable to use ceramic or film capacitors, which allows to increase the reliability of the generator and to improve its weight and size characteristics due to the higher specific capacitance of these types of capacitors.

These capacitors can be connected both parallel to the diodes 6, and between the connection points of the phase windings with the diodes 6 and the connection points of the additional diodes 8 with the keys 10 (transistors 11), as shown in FIG. 7.

In the modes of initial start-up and maximum output power of the generator, when the key 10 (transistor or transistor module 11) is constantly on (open), differences in the connection of capacitors 7 (Fig. 5 or 6) do not affect the operation of the generator.

The connection sequence of the additional diode 8 and the key 10 (transistor or transistor module 11) can be any. The polarity of inclusion of all diodes 6, additional diodes 8, thyristors 9 and transistors 11 can be reversed without disrupting the operability of the generator and its characteristics, provided that the polarity of inclusion of all these elements of the electric circuit of the generator is simultaneously changed.

When the generator is operating, the maximum reverse voltage on the diodes 6 and on the additional diodes 8 is relatively small - significantly less than the generator output voltage U _OUT . Due to this, in order to increase the generator efficiency, diodes with a Schottky barrier can be used as diodes 6 and additional diodes 8.

To control thyristors 9 or switches 10 (transistors 11), the generator includes a regulator of its output voltage 12. It generates control currents by one or all thyristors I _UPR (Fig. 4) or control voltage on the gates of one or all transistors U _UPR (Fig. 5, 6) from the condition of increasing or decreasing the excitation current of the generator, respectively, with a decrease or increase in its output voltage U _OUT relative to a predetermined value.

This controller can be made, in particular, in the form of an electronic on-off switch with a hysteresis loop, for example, based on an inverting Schmitt trigger, or in the form of a pulse modulator, for example, pulse-width or pulse-frequency. It is preferable to use a controller with the number of output control channels equal to the number of phases N of the generator, which, as a rule, coincides with the number of thyristors 9 or keys 10 (transistors 11).

Each channel of the generator output voltage regulator has an optoelectronic or transformer galvanic isolation between this regulator 12 and the corresponding thyristor 9 or key 10 (transistor 11). The electric power supply of this regulator can be carried out, in particular, from a separate low-power power source or from a low-voltage power supply of an electromechanical transmission in which a generator is used.

In order to reduce the overall dimensions and mass of the generator, its diodes 6, capacitors 7, as well as additional diodes 8 and thyristors 9 or keys 10 can be placed in the case, on the case or on the generator shield, which are used as coolers for these generator components. This technical solution is preferable to implementation in the case of liquid cooling of the generator.

The N-phase generator payload can be connected directly to its phase windings. In this case, the feedback signal necessary for the operation of the output voltage regulator of the generator 12 is generated using an additional low-power rectifier (not shown conventionally in the drawings).

The generator can also operate on an external or built-in multiphase (N-phase) half-wave rectifier 13, which is either made as a separate device or placed on a bearing shield or on the generator housing. This load R _H 14 enters a constant output voltage U _OUT. To smooth the ripple of this voltage parallel to the load (output terminals of the generator), a capacitive filter C _H 15 can be connected.

The generator operates as follows.

After the start of rotation of the rotor 2, its residual magnetization causes the emergence of an EMF in the additional stator windings (turns) 5. This EMF through an additional diode 8 and an open thyristor 9 or key 10 enters the diode 6. As a result, the initial excitation current begins to flow through the phase windings (along the contour of the triangle or polygon), which forms a stationary magnetic field of excitation. If necessary, the initial excitation current of the generator is generated using an additional low-power current source connected to one of the diodes 6 (not shown conditionally in the drawings).

When the excitation current flows along the tooth coils, the stator teeth (poles) acquire the opposite polarity. The magnetic fluxes of the poles (teeth) of the stator depend not only on the magnetomotive force (MDS), but also on their position relative to the teeth of the rotor. When the rotor rotates, the relationship of the magnetic flux with the stator tooth coils changes in time with a frequency f, which depends on the rotation speed n and the number of teeth of the rotor Z ₂ , f = n ⋅ Z ₂ .

As a result, symmetrical multiphase EMF is induced in the tooth coils and, accordingly, in the phase windings. Since the EMF of the individual phases of the generator are offset from each other by an angle of 120 ° (at N = 3), the total EMF, which is applied to the sources of the excitation currents (to diodes 6), is zero.

At the same time, in the additional coils (turns) 5 that form the source of the excitation current, an EMF occurs. It is rectified by an additional diode 8 or thyristor 9 and directly or through a key 10 (transistor 11) is supplied to the diode 6, increasing the field current of the field winding and, accordingly, creating an additional MDS field.

EMF from phase windings through a half-wave rectifier 13 is supplied to a load R _H 14, in parallel with which a capacitive filter C _H 15 can be connected.

In this case, half-wave load currents flow in phase windings, whose MDS in the stator teeth coincides with the MDS of the excitation current, i.e. load current increases the flow of excitation. This leads to improved efficiency and overall dimensions of the generator. At the same time, the presence of the indicated internal positive coupling in the load current helps to compensate for the armature reaction, which leads to an increase in the rigidity of the external characteristics of the generator.

As a result of the connection of capacitors 7 to the diodes 6, a capacitive current arises in the phase windings, ahead of the excitation source current by an angle of 90 °. This capacitive current creates a magnetic flux, which, while the rotor teeth are under the stator teeth, increases the magnetic flux of excitation, and when the stator teeth are opposite the rotor grooves, it reduces the main magnetic flux, thereby increasing the magnitude of the change in the magnetic flux in the stator poles (teeth). Therefore, the use of capacitors 7 also leads to an increase in efficiency and an improvement in the overall dimensions of the generator.

If it is necessary to regulate the output voltage of the generator, it additionally contains thyristors 9 or keys 10 (transistors 11), as well as an output voltage regulator of the generator 12, which controls these thyristors or keys, regulating the excitation current of the generator and, accordingly, maintaining its output voltage at a given level.

Other features of the proposed inductor generator do not require explanation, since they are clear from the drawings and scientific and technical literature.

For specialists in the art it is also clear that in addition to the described variants of the inductor generator, other options for its implementation are also possible based on the features set forth in the claims.

Claims (13)

1. An inductor generator with combined field windings and a stator, comprising a fixed stator with an explicit pole core and a multiphase winding made in the form of gear coils spanning the stator poles, additional coils located in at least one gear coil, or one or more additional coils, placed at the poles of the stator together with the gear coils, with additional turns or additional coils connected together in series and / or in parallel and form at least m there is one excitation current source, a rotating windingless rotor with a toothed core fixed to its shaft, the stator and rotor cores being made in the form of packets drawn from insulated sheets of electrical steel, the stator poles and the teeth of the rotor core are facing each other and are separated by an air gap, the tooth coils of each phase are connected together in series and / or in parallel and form phase windings, at least one diode connected in series to at least one of the phase windings, which connected by a triangle or polygon, at least one capacitor, as well as at least one additional diode, or an additional diode and a key, or a thyristor connected in series, with at least one excitation current source through an additional diode, or through a series connected an additional diode and a key, either connected to a diode through a thyristor, and at least one capacitor is connected in parallel with the diode or between the connection point of the diode with the phase winding and the connection point diode and ceiling elements key. 2. The inductor generator according to claim 1, characterized in that the diodes in series with which the capacitors are connected in parallel are connected in series to the windings of all phases. 3. The inductor generator according to claim 1, characterized in that it contains excitation current sources, the number of which is equal to the number of its phases, each source being made in the form of additional turns located in the gear coils, or in the form of additional coils placed together with the gear coils on two opposite or at all poles of the stator related to each phase, while additional turns or coils of each phase are connected together in series and / or in parallel and through additional diodes, or through atelno connected diodes and additional keys, or through the thyristors connected to the parallel connected diodes and a capacitor connected in series with each phase winding. 4. The inductor generator according to claim 1, characterized in that the keys are based on field-effect transistors with an insulated gate, or bipolar transistors with an insulated gate, or bipolar transistors combined into transistor modules. 5. The inductor generator according to claim 1, characterized in that it comprises an output voltage regulator of the inductor generator, adapted to control at least one thyristor or key. 6. The inductor generator according to claim 5, characterized in that the output voltage regulator of the inductor generator is configured to generate control signals of at least one thyristor or key from the condition of increasing or decreasing the excitation current of the inductor generator, respectively, when decreasing or increasing its output voltage relative to a preset value. 7. The inductor generator according to claim 6, characterized in that the output voltage regulator of the inductor generator is made in the form of an electronic on-off switch with a hysteresis loop or a pulse modulator. 8. The inductor generator according to claim 6, characterized in that the regulator of the output voltage of the inductor generator is made with a number of channels equal to the number of thyristors, or keys, or phases of the inductor generator, and these channels are galvanically isolated between the thyristors or keys and the regulator of the output voltage of the inductor generator. 9. The inductor generator according to claim 1, characterized in that the capacitors are made of ceramic or film. 10. The inductor generator according to claim 1, characterized in that the diodes and / or additional diodes are diodes with a Schottky barrier. 11. The inductor generator according to claim 1, characterized in that the diodes, capacitors, as well as additional diodes and switches or thyristors, are placed in the housing, or on the housing, or on the shield of the inductor generator. 12. The inductor generator according to claim 1, characterized in that it further comprises an integrated multiphase half-wave rectifier, which is located on the bearing shield, or in the housing, or on the housing of the inductor generator. 13. The inductor generator according to claim 1, characterized in that its serrated pole zone is made comb-shaped.

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