A current detection method and system for excitation of main motor of aviation three-stage generator

Abstract

The embodiment of the present invention discloses a current detection method and system for the excitation of the main motor of an aviation three-stage generator, and relates to the field of aviation three-stage generators. The present invention adds a set of detection coils on the stator side of the exciter, and generates an induced potential E in the detection coil through the harmonic component of the rotor armature magnetic potential. The armature magnetic potential has a low harmonic content, the magnetic circuit is not saturated, and the induced potential in the detection coil is proportional to the main motor excitation current, I F = k·E. The main motor excitation current I can be realized by measuring the induced potential E of the detection coil F The actual proportionality factor k needs to be determined experimentally. The three-stage generator can be installed on a separate platform on the ground for testing. This measurement method is simple and reliable, and basically does not change the structure of the motor and has no effect on the normal operation of the motor.

Description

Technical Field

[0001] The present invention relates to the field of aviation three-stage generators, and in particular to a current detection method and system for excitation of a main motor of an aviation three-stage generator. Background Art

[0002] Early aviation power sources were brushed generators, but the carbon brush structure was prone to sparks during the commutation process, and the air at high altitudes was thin, making commutation difficult. Brushed generators had poor reliability and maintainability. As aircraft power capacity grew, brushed generators were gradually phased out. The three-stage generator has been made brushless, and its reliability and maintainability have been greatly improved. It has been widely used in the aviation field as the main power source for aircraft.

[0003] In traditional three-stage generators, although the exciter and rotating rectifier realize brushless excitation of the main motor, sensors cannot be installed on the high-speed rotating rotor. The brushless structure also makes it impossible to directly measure the signals on the three-stage generator rotor, especially the main motor excitation current, which is an important parameter for voltage regulation and operating status monitoring of the three-stage generator and cannot be directly measured.

[0004] Therefore, how to detect the excitation current of the main motor and facilitate the voltage regulation control and status detection of the three-stage generator has become a topic that needs to be studied. Summary of the invention

[0005] The embodiment of the present invention provides a current detection method and system for the excitation of the main motor of an aviation three-stage generator. The main motor excitation current is measured by adding a detection coil on the stator of the exciter. The method is easy to implement and the means are simple and reliable. At the same time, the original structure of the motor does not need to be changed, and the original normal operation of the motor is not affected.

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

[0007] In a first aspect, an embodiment of the present invention provides a method, which is used for an aviation three-stage generator, wherein the main components of the aviation three-stage generator include: a main motor (1), an exciter (3), a permanent magnet exciter (4) and a motor shaft (5), wherein the main motor (1), the exciter (3) and the permanent magnet exciter (4) are coaxially installed using a three-stage motor, and a rotating rectifier (2) is installed on the rotor yoke of the exciter (3); the main motor (1) is an electrically excited synchronous generator, which is the main body for outputting electric energy; the exciter (3) is a rotating armature electrically excited synchronous generator, and the exciter (3) provides a DC excitation current to the excitation winding on the rotor of the main motor (1) through the rotating rectifier (2), thereby realizing brushless excitation; the permanent magnet exciter (4) is a permanent magnet synchronous generator, which supplies power to the voltage control unit and the exciter (3) of the aviation three-stage generator, so that the three-stage generator can work independently without relying on an external power supply. The exciter (3) comprises: an exciter stator core (31), an exciter winding (32), an exciter rotor core (33) and an exciter armature winding (34); a detection coil (36) is arranged on the stator side of the exciter (3);

[0008] The method comprises:

[0009] S1, measuring the induced electromotive force E in the detection coil (36);

[0010] S2. Determine the main motor excitation current I according to the induced electromotive force E in the detection coil (36). F For example, by measuring the induced electromotive force E in the detection coil (36), the main motor excitation current I can be indirectly measured. F . Among them, the excitation winding of the exciter adopts a single-phase DC excitation method, which generates a static constant magnetic field during stable operation and has no effect on the detection coil (36). The armature current of the exciter is a three-phase alternating current and contains a certain harmonic component. The generated harmonic magnetic field rotates in space. The generated harmonic magnetic field generates an induced electromotive force E in the detection coil (36), and the magnetic field intensity of the harmonic magnetic field is low, and the magnetic circuit is not saturated. The magnitude of the induced electromotive force E is related to the current I in the armature winding (34) of the exciter. ex The magnitude is proportional to the induced potential E and the main motor excitation current I F Proportional to I F = k·E. By measuring the induced electromotive force E in the detection coil (36), the main motor excitation current I can be indirectly measured. F It should be noted that due to the main motor excitation current I F The armature current I ex After being rectified by the rotating rectifier (2), the main motor DC excitation current I F The effective value of the exciter phase current I ex There is a proportional relationship between them.

[0011] In a second aspect, an embodiment of the present invention provides a system, the system comprising: the aviation three-stage generator, a computer device and an external sensor;

[0012] The main components of the aviation three-stage generator include: a main motor (1), an exciter (3), a permanent magnet exciter (4) and a motor shaft (5), wherein the exciter (3) includes: an exciter stator core (31), an exciter winding (32), an exciter rotor core (33) and an exciter armature winding (34), and a detection coil (36) is arranged on the stator side of the exciter (3);

[0013] The external sensor is used to measure the induced electromotive force in the detection coil (36);

[0014] The computer device is used to calculate the main motor excitation current according to the induced electromotive force in the detection coil (36) and record it in real time.

[0015] The three-stage generator has a brushless structure, but the brushless structure also makes it impossible to directly measure the signal on the rotor of the three-stage generator, especially the main motor excitation current I F , as an important parameter for voltage regulation and operation status monitoring of three-stage generators, cannot be measured directly. The current detection method and system for the excitation of the main motor of the aviation three-stage generator provided in the embodiment of the present invention realizes the measurement of the excitation current of the main motor by adding a detection coil on the stator of the exciter. Compared with the method of adding a sensor, the method of adding a detection coil is easy to implement and the means are simple and reliable. At the same time, the original structure of the motor does not need to be changed, and it has no effect on the original normal operation of the motor. The measured main motor excitation current I F It can be used as a feedback signal for the generator controller, a fault detection signal for the armature winding of the exciter, etc., and can be used in subsequent detection links or subsequent control links, which is conducive to real-time monitoring of the system operation status. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. 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 creative work.

[0017] Figure 1 A schematic diagram of the principle of a three-stage generator provided by an embodiment of the present invention;

[0018] Figure 2 A schematic diagram of the actual structure of a three-stage generator provided by an embodiment of the present invention;

[0019] Figure 3 A cross-sectional view of the exciter structure provided by an embodiment of the present invention;

[0020] Figure 4 A schematic diagram of a ground three-stage motor discrete platform provided by an embodiment of the present invention;

[0021] Figure 5 A schematic diagram of the simulation relationship between the main motor excitation current IF output by the exciter and the exciter armature current Iex provided in an embodiment of the present invention;

[0022] Figure 6 A schematic diagram of the simulation relationship between the detection coil induced potential E and the exciter armature current Iex provided in an embodiment of the present invention;

[0023] Figure 7 A schematic diagram of the corresponding relationship between the detection coil induced potential E and the main motor excitation current IF provided in an embodiment of the present invention;

[0024] Figure 8 A schematic structural diagram of a three-phase exciter provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is 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, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be interpreted as limiting the present invention. It can be understood by those skilled in the art that, unless specifically stated, the singular forms "one", "one", "said" and "the" used herein may also include plural forms. It should be further understood that the term "including" used in the specification of the present invention refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or their groups. It should be understood that when we say that an element is "connected" or "coupled" to another element, it can be directly connected or coupled to other elements, or there may also be intermediate elements. In addition, the "connection" or "coupling" used here may include wireless connection or coupling. The term "and / or" used herein includes any unit 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 terms and scientific terms) used herein have the same meaning as generally understood by those of ordinary skill in the art to which the present invention belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless defined as herein.

[0026] The embodiment of the present invention provides a current detection method for the excitation of the main motor of an aviation three-stage generator, and the method is used for an aviation three-stage generator, such as Figure 1-3 As shown, the main components of the aviation three-stage generator include: a main motor (1), an exciter (3), a permanent magnet exciter (4) and a motor shaft (5). Specifically, the main motor (1), the exciter (3) and the permanent magnet exciter (4) are coaxially installed using a three-stage motor, and the rotating rectifier (2) is installed on the rotor yoke of the exciter (3); the main motor (1) is an electrically excited synchronous generator, which is the main body of outputting electric energy; the exciter (3) is a rotating armature type electrically excited synchronous generator, and the exciter (3) provides a DC excitation current to the excitation winding on the rotor of the main motor (1) through the rotating rectifier (2), thereby realizing brushless excitation; the permanent magnet exciter (4) is a permanent magnet synchronous generator, which supplies power to the voltage control unit and the exciter (3) of the aviation three-stage generator, so that the three-stage generator can work independently without relying on an external power supply.

[0027] The exciter (3) comprises: an exciter stator core (31), an exciter winding (32), an exciter rotor core (33) and an exciter armature winding (34); a detection coil (36) is arranged on the stator side of the exciter (3);

[0028] The detection coil (36) is wound on the detection pole (35), and the detection pole (35) is made of non-magnetic conductive material. Figure 3 , a set of detection coils (36) is added on the stator side of the exciter (3), and the detection coils (36) are wound on the detection poles (35). The detection poles (35) are made of non-magnetic conductive materials and will not affect the magnetic circuit distribution of the exciter, and only play the role of installing and fixing the detection coils (36). Among them, the detection coils (36) are wound on the detection poles (35), and the detection poles (35) are arranged between two adjacent magnetic poles of the stator core (31) of the exciter. The detection poles (35) are fixed to the stator core (31) of the exciter by bolts or other means. The detection poles (35) are made of non-magnetic conductive materials and will not affect the main magnetic circuit of the exciter. The specific number of turns of the detection coil (36) depends on the free space between adjacent magnetic poles. In order to improve the detection accuracy, the number of turns is preferably more. The terminals of the detection coils (36) need to be led out.

[0029] The method comprises:

[0030] S1, measuring the induced electromotive force E in the detection coil (36);

[0031] S2. Determine the main motor excitation current I according to the induced electromotive force E in the detection coil (36). F .

[0032] In this embodiment, the main motor excitation current I can be indirectly measured by measuring the induced electromotive force E in the detection coil (36). F . Among them, the excitation winding of the exciter adopts a single-phase DC excitation method, which generates a static constant magnetic field during stable operation and has no effect on the detection coil (36). The armature current of the exciter is a three-phase alternating current and contains a certain harmonic component. The generated harmonic magnetic field rotates in space. The generated harmonic magnetic field generates an induced electromotive force E in the detection coil (36), and the magnetic field intensity of the harmonic magnetic field is low, and the magnetic circuit is not saturated. The magnitude of the induced electromotive force E is related to the current I in the armature winding (34) of the exciter. ex The magnitude is proportional to the induced potential E and the main motor excitation current I F Proportional to I F = k·E. By measuring the induced electromotive force E in the detection coil (36), the main motor excitation current I can be indirectly measured. F It should be noted that due to the main motor excitation current I F The armature current I exAfter being rectified by the rotating rectifier (2), the main motor DC excitation current I F The effective value of the exciter phase current I ex There is a proportional relationship between them.

[0033] In this embodiment, the determination of the main motor excitation current according to the induced electromotive force E in the detection coil (36) includes: determining the induced electromotive force E and the main motor excitation current I F The corresponding relationship between: I F = k·E, and the main motor excitation current is calculated according to the corresponding relationship, where k represents the proportionality coefficient. k = 0.7396. Specifically, Figure 3 As shown. Finite element simulation is used to verify the scheme. The excitation current I ef Parameterize and obtain the effective value of armature current I of different exciters ex The average value of the main motor excitation current I F , detect the effective value E of the induced potential of the coil, such as Figure 5 and Figure 6 As shown in the figure, the armature current of the exciter varies in the range of 0 to 33A during normal operation. It can be seen from the figure that within this range, the magnitude of the induced potential E is proportional to the current I in the armature winding of the exciter. ex is proportional to the size of E = k1·I ex =1.7760I ex ; Main motor excitation current I F The armature current I of the exciter ex Also proportional to I F =k2·I ex =1.3136I ex From this, we can get the induced potential E in the detection coil and the main motor excitation current I F There is also a linear correspondence between them, such as Figure 7 As shown. According to the simulation results, the specific linear quantitative relationship can be calculated as I F =k·E=k2 / k1·E=0.7396E.

[0034] Optionally, in this embodiment, the aviation three-stage generator can be installed on a ground-based discrete platform, and the main motor (1), the exciter (3) and the permanent magnet exciter (4) are coaxially installed using a three-stage motor; the main motor (1) is an electrically excited synchronous generator; the exciter (3) is a rotating armature electrically excited synchronous generator; the permanent magnet exciter (4) is a permanent magnet synchronous generator, which supplies power to the voltage control unit and the exciter (3) of the aviation three-stage generator; and a carbon brush slip ring (6) and a ground static rectifier (7) are also installed in the aviation three-stage generator.

[0035] For example: Main motor excitation current IF The actual proportionality coefficient k between the induced potential E needs to be determined experimentally. The three-stage generator is installed on a ground-based discrete platform for testing. The ground-based discrete platform cancels the rotating rectifier (2) and installs a carbon brush slip ring (6). The signals on the exciter rotor and the main motor rotor are led out, and the function of the rotating rectifier (2) is replaced by the ground-based static rectifier (7). The main motor excitation current I can be directly measured. F In practical applications, the main motor excitation current I F The actual proportionality coefficient k between the induced potential E can be determined experimentally. The three-stage generator is installed on a separate platform ( Figure 4 ) is tested on a ground station. The main motor (1), exciter (3) and permanent magnet exciter (4) are still coaxially installed. The difference in structure from the actual three-stage generator is that the rotating rectifier (2) is eliminated and a carbon brush slip ring (6) is installed to lead out the signals on the exciter rotor and the main motor rotor. The function of the rotating rectifier (2) is replaced by a ground stationary rectifier (7), so that the main motor excitation current I can be directly measured. F .

[0036] The towing motor drags the three-stage generator installed on the separate platform to the generating speed, and adjusts the input excitation current I of the exciter (3). ef ’ , so that the main motor excitation current I F ’ The effective value E of the induced potential in the detection coil (36) is measured by an instrument within the range required for actual operation. ’ and the main motor excitation current I F ’ , collect test data, and obtain the proportionality coefficient k = I F ’ / E ’ .

[0037] Optionally, this embodiment also provides an alternative solution to the above embodiment. The method for detecting the excitation current of the main motor of the three-stage generator is basically the same as the above embodiment, except that the exciter in the above embodiment is a single-phase exciter (3), and the excitation winding is a single-phase concentrated winding (32), while in the alternative solution of this embodiment, the exciter replaces the three-phase exciter, for example Figure 8As shown, the excitation winding is a three-phase distributed winding (82), the excitation machine rotor core (83), and the excitation machine armature winding (84) are the same as the excitation machine rotor core (33) and the excitation machine armature winding (34) of the excitation machine (3). The three-phase excitation machine uses two phases of the three-phase excitation winding to be series-connected for excitation during power generation. One phase does not work during power generation, and the inactive phase winding can be directly used as a detection coil without the need to add an additional detection coil. Therefore, the induced potential of the idle phase winding can be measured to indirectly measure the main motor excitation current.

[0038] This embodiment also provides a current detection system for the excitation of the main motor of an aviation three-stage generator, the system comprising: the aviation three-stage generator, a computer device and an external sensor;

[0039] The main components of the aviation three-stage generator include: a main motor (1), an exciter (3), a permanent magnet exciter (4) and a motor shaft (5), wherein the exciter (3) includes: an exciter stator core (31), an exciter winding (32), an exciter rotor core (33) and an exciter armature winding (34), and a detection coil (36) is arranged on the stator side of the exciter (3);

[0040] The external sensor is used to measure the induced electromotive force in the detection coil (36);

[0041] The computer device is used to calculate the main motor excitation current according to the induced electromotive force in the detection coil (36) and record it in real time.

[0042] The computer device is specifically used to determine the induced electromotive force E and the main motor excitation current I F The corresponding relationship between: I F =k·E, and the main motor excitation current is calculated according to the corresponding relationship, wherein k represents the proportional coefficient.

[0043] The three-stage generator has a brushless structure, but the brushless structure also makes it impossible to directly measure the signal on the rotor of the three-stage generator, especially the main motor excitation current I F , as an important parameter for voltage regulation and operation status monitoring of three-stage generators, cannot be measured directly. In this embodiment, a set of detection coils is added on the stator side of the exciter to generate an induced potential E in the detection coil through the harmonic component of the rotor armature magnetic potential. The armature magnetic potential has a low harmonic content, the magnetic circuit is not saturated, and the induced potential in the detection coil is proportional to the main motor excitation current, I F = k·E. The main motor excitation current I can be realized by measuring the induced potential E of the detection coil FThe actual proportionality factor k needs to be determined experimentally. The three-stage generator can be installed on a separate platform on the ground for testing. This measurement method is simple and reliable, and basically does not change the structure of the motor and has no effect on the normal operation of the motor.

[0044] Advantages of this embodiment: 1. The present invention adds a set of detection coils on the stator of the exciter, and the measurement method is simple, reliable, and easy to implement, and the structure of the motor is basically not changed, and the normal operation of the motor is not affected; 2. The measured main motor excitation current I F It can be used as feedback signal of generator controller, fault detection signal of exciter armature winding, etc., which is beneficial to real-time monitoring of system operation status.

[0045] 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 implementation method of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or replacements that can be easily thought of by any technician familiar with the 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 current detection method for the excitation of the main motor of an aviation three-stage generator, characterized in that: The method is used for an aviation three-stage generator, the main components of which include: a main motor (1), an exciter (3), a permanent magnet exciter (4) and a motor shaft (5), wherein the exciter (3) includes: an exciter stator core (31), an exciter winding (32), an exciter rotor core (33) and an exciter armature winding (34), and a detection coil (36) is arranged on the stator side of the exciter (3); The method comprises: S1, measuring the induced electromotive force E in the detection coil (36); S2. Determine the main motor excitation current I according to the induced electromotive force E in the detection coil (36). F ; Induced potential E The magnitude of the current in the armature winding of the exciter I ex is proportional to the size of E = k 1 •I ex =1.7760 I ex ; Main motor excitation current I F The armature current of the exciter I ex Also proportional I F = k 2 ·I ex =1.3136 I ex ; E and I F The corresponding relationship between them: I F = k·E , I F = k·E = k 2 / k 1 ·E =0.7396 E , k represents the proportionality coefficient, and the main motor excitation current is calculated according to the corresponding relationship; The aviation three-stage generator is installed on a ground-based discrete platform to perform an experimental determination of the proportional coefficient k, and the main motor (1), the exciter (3) and the permanent magnet exciter (4) are coaxially installed using a three-stage motor; The exciter (3) is a three-phase exciter. The excitation winding of the exciter (3) is a three-phase distributed winding (82). When the three-phase exciter is in power generation operation, two phases of the three-phase excitation winding are connected in series for excitation. One phase does not work during power generation, and the inactive phase winding is directly used as a detection coil.

2. The method according to claim 1, characterized in that The main motor (1) is an electrically excited synchronous generator; the exciter (3) is a rotating armature type electrically excited synchronous generator; and the permanent magnet exciter (4) is a permanent magnet synchronous generator, which supplies power to the voltage control unit and the exciter (3) of the aviation three-stage generator.

3. The method according to claim 2, characterized in that The ground-mounted discrete platform is equipped with a carbon brush slip ring (6) and a ground-mounted static rectifier (7).

4. A current detection system for the excitation of the main motor of an aviation three-stage generator, characterized in that: The system includes: the aviation three-stage generator, computer equipment and external sensors; The main components of the aviation three-stage generator include: a main motor (1), an exciter (3), a permanent magnet exciter (4) and a motor shaft (5), wherein the exciter (3) includes: an exciter stator core (31), an exciter winding (32), an exciter rotor core (33) and an exciter armature winding (34), and a detection coil (36) is arranged on the stator side of the exciter (3); The external sensor is used to measure the induced electromotive force in the detection coil (36); The computer device is used to calculate the main motor excitation current based on the induced electromotive force in the detection coil (36) and record it in real time; The computer device is specifically used to determine the induced electromotive force E and the main motor excitation current I F Correspondence between: Induced potential E The magnitude of the current in the armature winding of the exciter I ex is proportional to the size of E = k 1 •I ex =1.7760 I ex ; Main motor excitation current I F The armature current of the exciter I ex Also proportional I F = k 2 ·I ex =1.3136 I ex ; E and I F The corresponding relationship between them: I F = k·E , I F = k·E = k 2 / k 1 ·E =0.7396 E , k represents the proportionality coefficient, and the main motor excitation current is calculated according to the corresponding relationship; The aviation three-stage generator is installed on a ground-based discrete platform to perform an experimental determination of the proportional coefficient k, and the main motor (1), the exciter (3) and the permanent magnet exciter (4) are coaxially installed using a three-stage motor; The exciter (3) is a three-phase exciter. The excitation winding of the exciter (3) is a three-phase distributed winding (82). When the three-phase exciter is in power generation operation, two phases of the three-phase excitation winding are connected in series for excitation. One phase does not work during power generation, and the inactive phase winding is directly used as a detection coil.

Images