Capacitance phase shift type double-winding single-phase excitation system

Abstract

The embodiment of the invention discloses a capacitance phase-shifting type double-winding single-phase excitation system, and relates to the technical field of aviation three-stage starting generators. In the starting stage, two phases of exciting windings of the exciter are connected in parallel, a capacitor is connected in series in one phase of winding, the value of the capacitor is matched with the resistance-inductance parameter of a stator winding of the exciter, a single-phase constant-voltage constant-frequency alternating-current power supply is connected, approximate two-phase alternating-current exciting current is obtained through the phase shifting effect of the capacitor, and an oval rotating magnetic field is formed in the exciter. In the power generation stage, the exciter is connected to the generator control unit to obtain direct-current exciting current, and two phases of windings of the exciter stator are connected in series to form a single-phase winding. According to the scheme, the advantages of starting two-phase alternating-current excitation and generating direct-current excitation can be considered at the same time, the high winding utilization rate needs to be achieved, and the excitation control difficulty can be lowered.

Description

Technical Field

[0001] The present invention relates to the technical field of aviation three-stage starter generators, and in particular to a capacitor phase-shifted double-winding single-phase excitation system. Background Art

[0002] As a crucial component of an aircraft's main power system, the three-stage motor has been widely used in aviation. This motor system primarily consists of core components such as the main generator, exciter, permanent magnet exciter, and rotating rectifier. With the rapid advancement of aviation electrification technology, the three-stage motor has achieved dual-function integration for starting and generating, enabling it to operate in an electric mode to start aircraft engines. In generating mode, the aircraft engine drives the three-stage motor. The permanent magnet exciter, through the rectifier circuit built into the generator control unit, provides adjustable DC excitation current to the exciter, which in turn excites the main generator, ultimately generating electrical energy. In starting mode, the starting controller injects current into the main generator, generating sufficient torque to start the engine. During this time, the exciter remains in generating mode, continuously providing excitation current to the main generator. However, the design of traditional three-stage motors is mainly optimized for power generation performance, and there is a technical problem of excitation difficulty under starting conditions: when the motor is stationary or running at low speed, since the exciter adopts a single-phase DC excitation winding structure, it is difficult to provide sufficient excitation power for the main generator under low speed conditions.

[0003] To address this issue, current solutions require AC excitation in starting mode, where the motor speed is relatively low. Two-phase AC excitation offers higher energy transmission efficiency than single-phase AC excitation. However, the excitation current output by the exciter in two-phase AC excitation varies significantly with speed, requiring a specialized excitation controller to adjust the excitation voltage amplitude and frequency in real time. This makes control more complex. Single-phase AC excitation, on the other hand, places lower demands on the excitation power supply, allowing for a constant voltage and frequency single-phase AC power supply. During the power generation phase, the motor operates at medium to high speeds, typically requiring traditional DC excitation, which offers simple and reliable control.

[0004] Therefore, the new design goal is to simultaneously take into account the advantages of starting two-phase AC excitation and generating DC excitation without adding a large number of new structural parts, while also achieving high winding utilization and reducing the difficulty of excitation control. How to design and improve a single-phase AC / DC excitation scheme for aviation three-stage starter generators that can simultaneously take into account the advantages of starting two-phase AC excitation and generating DC excitation, while also achieving high winding utilization and reducing the difficulty of excitation control has become a topic that requires in-depth research. Summary of the Invention

[0005] An embodiment of the present invention provides a capacitor phase-shifted dual-winding single-phase excitation system that can simultaneously take into account the advantages of starting two-phase AC excitation and generating DC excitation, while also having a high winding utilization rate and reducing the difficulty of excitation control.

[0006] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions:

[0007] A capacitor phase-shifted double-winding single-phase excitation system is used for a three-stage brushless synchronous motor. The rotor portion of the three-stage brushless synchronous motor comprises: a main motor (1), a rotating rectifier (2), an exciter (3), and a permanent magnet exciter (4).

[0008] The rotor part of the exciter (3) adopts a three-phase armature winding structure

[0009] The stator portion of the exciter (3) includes two phase excitation windings, namely, phase A (31) and phase B (32), and the two phase excitation windings are spaced apart by an electrical angle of 90°.

[0010] The A-phase (31) and B-phase (32) windings are both open winding structures, and the two ports of each phase winding are led out by wires;

[0011] The B-phase winding (32) is connected in series with the phase-shifting capacitor C (5);

[0012] The generator control unit (7) and the single-phase constant voltage constant frequency AC power supply (8) are respectively connected to a switching device in the switching switch (6);

[0013] The operating modes of the capacitor phase-shifted dual-winding single-phase excitation system include at least a starting mode and a power generation mode.

[0014] The main motor (1) is an electrically excited synchronous motor, the exciter (3) is a rotating armature electrically excited synchronous generator, and the permanent magnet exciter (4) is a permanent magnet synchronous generator. Brushless excitation of the main motor (1) is achieved through the exciter (3) and the rotating rectifier (2).

[0015] In the starting mode, the contact 66 and the contact 69 of the switching switch (6) are closed, and the contact 67 and the contact 611 are closed, thereby connecting to the single-phase AC power supply. The contact 64 and the contact 61 of the switching switch (6) are closed, and the contact 65 and the contact 63 are closed, so that the phase-shifting capacitor C (5) is connected in series with the B-phase winding (32). The phase-shifting capacitor C (5) causes the current of the B-phase winding (32) to have a phase difference in time, thereby obtaining a two-phase AC excitation current. At this time, an elliptical rotating magnetic field is formed inside the exciter (3); when the main motor (1) reaches the disconnecting speed and completes the starting, the switching device in the switching switch (6) is disconnected from the output end of the single-phase AC power supply (8) and the phase-shifting capacitor C (5).

[0016] In a preferred embodiment, the single-phase constant voltage and constant frequency AC power source (8) is a 115V / 400Hz AC power source.

[0017] In the power generation mode, the contact 66 and the contact 68 in the switching switch (6) are closed, the contact 67 and the contact 610 are closed, and the contact 65 and the contact 63 are closed, so that the two windings of the A phase (31) and the B phase (32) are connected in series to form a single-phase winding structure, and are connected to the generator control unit (8) to obtain a DC excitation current; the exciter (3) provides the excitation current to the rotor of the main motor (1) in both the starting mode and the power generation stage.

[0018] In the power generation mode, the three-phase AC current generated by the permanent magnet exciter (4) is input to the generator control unit (7), and is rectified by the generator control unit (7), thereby inputting a DC excitation current to the exciter (3);

[0019] In the power generation mode, the contact 64 is disconnected from the contact 61, the contact 65 is closed to the contact 63, and the two-phase windings of phase A (31) and phase B (32) are connected in series to form a single-phase winding structure;

[0020] The composite magnetic field formed inside the exciter (3) after the two-phase windings of phase A (31) and phase B (32) are connected in series causes the exciter (3) to generate direct current excitation.

[0021] Specifically, the value of the phase-shifting capacitor C(5) is R The relationship with the parameters of the stator excitation winding of the exciter (3) includes:

[0022]

[0023] Among them, L s_2D represents the self-inductance of the stator excitation winding of the exciter (3), L s_end represents the end leakage inductance of the stator excitation winding of the exciter (3), and ω1 is the angular frequency of the excitation power supply.

[0024] In the preferred solution, L s_2D =9.53mH, L s_end =1.40mH, ω1=2πf1=800π, C can be calculated R ≈15μF.

[0025] The capacitor phase-shifted dual-winding single-phase excitation system provided in an embodiment of the present invention can meet the excitation requirements of an aviation three-stage starter generator in two different working modes: starting and generating. In the starting stage, the two-phase excitation windings of the exciter are connected in parallel, and a capacitor is connected in series in one of the phase windings. The capacitor value matches the resistance-inductance parameters of the stator winding of the exciter. A single-phase constant voltage and constant frequency AC power supply is connected. Through the phase-shifting effect of the capacitor, an approximate two-phase AC excitation current is obtained, and an elliptical rotating magnetic field is formed inside the exciter. When the motor reaches the disengagement speed and completes starting, the AC source and the capacitor are cut off. In the generating stage, the exciter is connected to the generator control unit to obtain the DC excitation current, and the two-phase windings of the exciter stator are connected in series to form a single-phase winding. Compared to traditional single-phase AC excitation systems, this invention offers the advantages of higher output power and efficiency. Compared to three-phase and two-phase AC excitation systems, the exciter itself can maintain a substantially constant output current, resulting in simple implementation and the elimination of complex excitation control strategies. Furthermore, the invention can switch between AC and DC excitation modes, employing single-phase AC excitation during the startup phase and DC excitation during the power generation phase. This allows for the simultaneous utilization of both two-phase AC excitation for startup and DC excitation for power generation, resulting in high winding utilization and reduced excitation control complexity. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 A schematic diagram of the principle of a capacitor phase-shifted dual-winding single-phase excitation system provided by an embodiment of the present invention;

[0028] Figure 2 A schematic diagram of a system connection method when AC excitation is used during the startup phase provided by an embodiment of the present invention;

[0029] Figure 3 A schematic diagram of a system connection method when DC excitation is used in the power generation stage according to an embodiment of the present invention;

[0030] Figure 4 A vector diagram of excitation voltage and excitation current when single-phase AC excitation is used during the starting phase provided by an embodiment of the present invention;

[0031] Figure 5 A schematic diagram of the excitation rotating magnetic potential when single-phase AC excitation is used during the starting phase provided by an embodiment of the present invention;

[0032] Figure 6A schematic diagram of a finite element model of an exciter (3) provided in an embodiment of the present invention;

[0033] Figure 7 A schematic diagram of a field-circuit coupling simulation model of an exciter (3) provided in an embodiment of the present invention;

[0034] Figure 8 Schematic diagram of output characteristics of a single-phase exciter and a two-phase exciter under DC excitation mode provided by an embodiment of the present invention;

[0035] Figure 9 A schematic diagram of current waveforms of two-phase excitation windings of an exciter when a single-phase AC power supply is used during the starting phase, provided by an embodiment of the present invention;

[0036] Figure 10 A schematic diagram comparing the effective value of the excitation current of a 115V / 400Hz excitation power supply + 15μF phase-shifting capacitor (5) double-winding single-phase excitation system provided by an embodiment of the present invention with that of a conventional single-phase AC excitation method under the same excitation conditions;

[0037] Figure 11 A schematic diagram comparing the output current average value of a 115V / 400Hz excitation power supply + 15μF phase-shifting capacitor (5) dual-winding single-phase excitation system provided by an embodiment of the present invention with that of a conventional single-phase AC excitation method under the same excitation conditions;

[0038] Figure 12 A schematic diagram comparing the excitation efficiency of a 115V / 400Hz excitation power supply + 15μF phase-shifting capacitor (5) double-winding single-phase excitation system provided by an embodiment of the present invention with that of a conventional single-phase AC excitation method under the same excitation conditions;

[0039] Figure 13 A schematic diagram showing a comparison of the stator-side power factor of the exciter using a 115V / 400Hz excitation power supply + 15μF phase-shifting capacitor (5) dual-winding single-phase excitation system provided by an embodiment of the present invention and a conventional single-phase AC excitation method under the same excitation conditions. DETAILED DESCRIPTION

[0040] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. The embodiments of the present invention will be described in detail below, with examples of the embodiments illustrated in the accompanying drawings. Throughout, identical or similar reference numerals represent identical or similar elements or elements having identical or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and intended only to explain the present invention and are not to be construed as limiting the present invention. Those skilled in the art will appreciate that, unless otherwise stated, the singular forms "a," "an," "said," and "the" used herein may also include the plural forms. It should be further understood that the term "comprising" as used in the description of the present invention refers to the presence of the stated features, integers, steps, operations, elements, and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when an element is referred to as being "connected" or "coupled" to another element, it may be directly connected or coupled to the other element, or intervening elements may be present. Furthermore, "connected" or "coupled" as used herein may include wireless connections or couplings. The term "and / or" as used herein includes any and all combinations of one or more associated listed items. It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with their meanings in the context of the prior art, and will not be interpreted in an idealized or overly formal sense unless defined as such herein.

[0041] An embodiment of the present invention provides a capacitor phase-shifted dual-winding single-phase excitation system that can simultaneously take into account the advantages of starting two-phase AC excitation and generating DC excitation, while also having a high winding utilization rate and reducing the difficulty of excitation control.

[0042] The basic structure of a traditional three-stage motor includes: a main motor (1), a rotating rectifier (2), an exciter (3), a permanent magnet exciter (4) and an external generator control unit (7).

[0043] The main motor (1) is an electrically excited synchronous motor, the exciter (3) is a rotating armature electrically excited synchronous generator, and the permanent magnet exciter (4) is a permanent magnet synchronous generator. The exciter (3) and the rotating rectifier (2) realize brushless excitation of the main motor (1).

[0044] The embodiment of the present invention provides a capacitor phase-shifted double-winding single-phase excitation method for an aviation three-stage starter generator, such as Figure 1As shown, it includes: a main motor (1), a rotating rectifier (2), an exciter (3), a permanent magnet exciter (4), a phase-shifting capacitor (5), a switch (6), a generator control unit (7) and a single-phase constant voltage and constant frequency AC power supply (8);

[0045] The rotor part of the exciter (3) is a three-phase armature winding, and the stator part of the exciter (3) includes two-phase excitation windings, namely, phase A (31) and phase B (32). The two-phase excitation windings are 90 degrees apart in electrical angle in space. The phase A (31) and phase B (32) windings are both open winding structures, and the two ports of each phase winding are led out by wires.

[0046] The B-phase winding (32) is connected in series with the phase-shifting capacitor C (5).

[0047] In start mode, if Figure 2 As shown, the switch (6) is connected to the single-phase constant voltage and constant frequency AC power supply (8), and the phase shift capacitor C (5) is connected in series with the B-phase winding (32). The phase shift capacitor C (5) causes the current of the B-phase winding (32) to have a phase difference in time, thereby obtaining a two-phase AC excitation current and forming an elliptical rotating magnetic field inside the exciter (3). When the motor reaches the disconnecting speed and completes the start, the single-phase constant voltage and constant frequency AC power supply (8) and the phase shift capacitor (5) are cut off. Figure 4 、 5 ;

[0048] In power generation mode, Figure 3 As shown, the exciter (3) is connected to the generator control unit (7) to obtain DC excitation current, and the two-phase windings of the stator of the exciter (3) are connected in series to form a single-phase winding. The exciter (3) provides excitation current to the rotor of the main motor (1) during the starting stage and the power generation stage of the aviation three-stage starter generator.

[0049] This embodiment can use finite element + external circuit joint simulation to verify the solution, such as Figure 6 、 7 As shown, a finite element simulation model of the exciter was built in Ansys Maxwell software. During the simulation, the excitation power supply was set to a 115V / 400Hz constant voltage and constant frequency single-phase AC power supply (8). The phase-shifting capacitor C (5) was calculated using the following formula:

[0050]

[0051] Among them, the self-inductance of the excitation machine stator excitation winding L s_2D and terminal leakage inductance L s_end It can be obtained by finite element simulation calculation, ω1 is the angular frequency of the excitation power supply.

[0052] In this embodiment, L s_2D =9.53mH, L s_end=1.40mH, ω1=2πf1=800π, C can be calculated R ≈15μF.

[0053] In order to compare the output characteristics of the two-phase exciter of the embodiment of the present invention with the original single-phase exciter, only the stator slot shape and the stator excitation winding configuration are changed. Under the DC excitation mode, the newly designed two-phase exciter has basically the same input and output characteristics as the original single-phase exciter. Figure 8 shown.

[0054] like Figure 10 、 11 , 12, 13. In the starting mode, the stator of the exciter (3) is input with a 115V / 400Hz single-phase AC power supply. The output characteristics of the newly designed two-phase exciter and the original single-phase exciter are compared. The results show that the excitation performance of this capacitor phase-shifted dual-winding single-phase AC excitation method is better than that of the traditional single-phase excitation method.

[0055] This embodiment can meet the excitation requirements of an aviation three-stage starter generator in both starting and generating modes. During the starting phase, the exciter's two-phase excitation windings are connected in parallel, with one phase winding connected in series with a capacitor whose value matches the resistance and inductance parameters of the exciter's stator winding. A single-phase constant-voltage, constant-frequency AC power source is connected. The capacitor's phase shifting effect produces a near-two-phase AC excitation current, forming an elliptical rotating magnetic field within the exciter. Once the motor reaches the disconnect speed and completes starting, the AC source and capacitor are disconnected. During the generating phase, the exciter connects to the generator control unit to obtain DC excitation current, and the two-phase stator windings of the exciter are connected in series to form a single-phase winding. Compared to traditional single-phase AC excitation systems, this invention offers the advantages of higher output power and efficiency. Compared to three-phase and two-phase AC excitation systems, the exciter itself can maintain a substantially constant output current, resulting in simple implementation and the elimination of complex excitation control strategies. Furthermore, it can switch between AC and DC excitation modes, using single-phase AC excitation during the starting phase and DC excitation during the generating phase.

[0056] The main advantages of this embodiment are:

[0057] 1. Compared with the traditional single-phase AC excitation system, this embodiment has the advantages of higher output current, excitation efficiency and power factor;

[0058] 2. Compared with three-phase and two-phase AC excitation systems, the exciter of this embodiment can maintain a substantially constant output current by itself, thereby having the advantages of simple implementation and no need for complex excitation control strategies;

[0059] 3. This embodiment can realize the switching of AC / DC excitation mode, and can adopt single-phase AC excitation mode in the starting stage and DC excitation mode in the power generation stage;

[0060] 4. The two-phase windings of the stator of the exciter (3) of this embodiment can be fully reused in both AC and DC excitation modes, and the winding utilization rate is high.

[0061] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited to this. Any changes or replacements that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A capacitor phase-shifted dual-winding single-phase excitation system, characterized in that: Used for a three-stage brushless synchronous motor, the rotor part of the three-stage brushless synchronous motor comprises: a main motor (1), a rotating rectifier (2), an exciter (3) and a permanent magnet exciter (4); The rotor part of the exciter (3) adopts a three-phase armature winding structure; The stator portion of the exciter (3) includes two phase excitation windings, namely, phase A (31) and phase B (32), and the two phase excitation windings are spaced apart by an electrical angle of 90°. The A-phase (31) and B-phase (32) windings are both open winding structures, and the two ports of each phase winding are led out by wires; The B-phase winding (32) is connected in series with the phase-shifting capacitor C (5); The generator control unit (7) and the single-phase constant voltage constant frequency AC power supply (8) are respectively connected to a switching device in the switching switch (6); The operating modes of the capacitor phase-shifted dual-winding single-phase excitation system include at least a starting mode and a power generation mode.

2. The capacitor phase-shifted dual-winding single-phase excitation system according to claim 1, characterized in that: The main motor (1) is an electrically excited synchronous motor, the exciter (3) is a rotating armature electrically excited synchronous generator, and the permanent magnet exciter (4) is a permanent magnet synchronous generator.

3. The capacitor phase-shifted dual-winding single-phase excitation system according to claim 1, characterized in that: In the starting mode, the contact 66 and the contact 69 of the switching switch (6) are closed, and the contact 67 and the contact 611 are closed, thereby connecting to the single-phase AC power supply. The contact 64 and the contact 61 of the switching switch (6) are closed, and the contact 65 and the contact 63 are closed, thereby connecting the phase-shifting capacitor C (5) in series with the B-phase winding (32). The phase-shifting capacitor C (5) causes the current of the B-phase winding (32) to have a phase difference in time, thereby obtaining a two-phase AC excitation current. At this time, an elliptical rotating magnetic field is formed inside the exciter (3); When the main motor (1) reaches the disconnecting speed and completes starting, the switching device in the switch (6) is disconnected from the output end of the single-phase AC power supply (8) and the phase-shifting capacitor C (5).

4. The capacitor phase-shifted dual-winding single-phase excitation system according to claim 1, characterized in that: The single-phase constant voltage constant frequency AC power supply (8) is a 115V / 400Hz AC power supply.

5. The capacitor phase-shifted dual-winding single-phase excitation system according to claim 1, characterized in that: In the power generation mode, the contact 66 and the contact 68 in the switching switch (6) are closed, the contact 67 and the contact 610 are closed, and the contact 65 and the contact 63 are closed, so that the two windings of the A phase (31) and the B phase (32) are connected in series to form a single-phase winding structure, and are connected to the generator control unit (8) to obtain a DC excitation current.

6. The capacitor phase-shifted dual-winding single-phase excitation system according to claim 5, characterized in that: In the power generation mode, the three-phase AC current generated by the permanent magnet exciter (4) is input to the generator control unit (7), and is rectified by the generator control unit (7), thereby inputting a DC excitation current to the exciter (3); The exciter (3) provides excitation current to the rotor of the main motor (1) in both the starting mode and the power generation stage.

7. The capacitor phase-shifted dual-winding single-phase excitation system according to claim 1 or 4, characterized in that: In the power generation mode, the contact 64 is disconnected from the contact 61, the contact 65 is closed to the contact 63, and the two-phase windings of the A phase (31) and the B phase (32) are connected in series to form a single-phase winding structure; The composite magnetic field formed inside the exciter (3) after the two-phase windings of phase A (31) and phase B (32) are connected in series causes the exciter (3) to generate direct current excitation.

8. The capacitor phase-shifted dual-winding single-phase excitation system according to claim 1, characterized in that: The value of the phase shift capacitor C(5) is R The relationship between the parameters of the stator excitation winding of the exciter (3) is as follows: include: Among them, L s_2D represents the self-inductance of the stator excitation winding of the exciter (3), L s_end represents the end leakage inductance of the stator excitation winding of the exciter (3), and ω1 is the angular frequency of the excitation power supply.

9. The capacitor phase-shifted dual-winding single-phase excitation system according to claim 1, characterized in that: L s_2D =9.53mH,L s_end = 1.40mH, ω1 = 2πf1 = 800π.

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