Magnetic conductance modulation type excitation generator containing main motor rotor position information

Abstract

The invention discloses a magnetic conductance modulation type excitation generator containing position information of a main motor rotor, a rotor of the excitation generator is designed to be of an unequal-pole salient-pole magnetic conductance modulation structure, when the motor runs at a low-speed section, the unequal-pole magnetic conductance modulation type rotor structure is in a rotating state, magnetic conductance change of a magnetic circuit can be caused, and the magnetic conductance of the magnetic circuit can be changed. And therefore, the amplitude of the excitation current in the parallel branch at the stator side of the excitation generator is periodically changed, and the amplitude change is consistent with the number of salient pole structures of the rotor in a mechanical period. Through an amplitude demodulation method, an envelope line formed by amplitude change of excitation current can be utilized to demodulate rotor position angle information of the excitation generator contained in the envelope line. Furthermore, according to a three-stage starter / generator mechanical structure in which a main motor and a main exciter are coaxially installed, corresponding rotor position information of the main motor can be directly detected, and then the information is fed back to a control link, so that the motor is smoothly started, the signal extraction time is shortened, and the rotor position detection precision is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of aviation three-stage starting / generating systems, and in particular to a magnetic permeability modulation excitation generator including main motor rotor position information. Background Art

[0002] Since the concept of all-electric aircraft was proposed, the electrification of aircraft has developed more and more significantly. The proportion of onboard electrical loads has increased significantly, and the power supply capacity has increased to 1450kVA. The aviation three-stage starter / generator (hereinafter referred to as "TSSG") consists of an auxiliary exciter, a main excitation generator, a rotating rectifier and a main motor. It is widely used in aircraft starting systems due to its advantages of brushless and high reliability. However, accurate main motor rotor position information is the primary condition for starting, and traditional mechanical position sensors will occupy additional aviation power system volume and weight, and are susceptible to electromagnetic interference, reducing the reliability of the aviation power system. On the other hand, the rotor position detection method based on the back-EMF model commonly used in general motors will cause the back-EMF signal containing the rotor position information to be weak due to the low speed, which has a great impact on the detection accuracy.

[0003] The existing TSSG rotor position detection usually utilizes the multi-stage structure characteristics, adopts the method of injecting signals from the stator side of the excitation generator / main motor, and extracting signals from the stator side of the corresponding main motor / main excitation generator. However, the rotor position signals transmitted based on the forward / reverse signal transmission mechanism will be affected by the rotor speed, nonlinear rotating rectifier and main motor damping winding, resulting in unstable signal transmission, low sensitivity and other problems that affect the detection accuracy; among them, the detection method using the harmonic signal generated by the motor itself will increase the rotor position estimation error due to the attenuation of the extracted harmonic signal and the mutual interference with the harmonics of the main generator starting controller. Furthermore, the power of the general three-stage aviation starter / generator is relatively large, and the high-frequency voltage signal amplitude that needs to be injected at the necessary signal-to-noise ratio is high, which is easy to cause large starting output torque pulsation.

[0004] Therefore, the prior art still needs to be improved and enhanced. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a magnetic permeability modulated excitation generator that contains the main motor rotor position information, aiming to solve the problems in the prior art of weak back-electromotive force signal of rotor position detection in the low-speed section of aviation three-stage starter / generator and signal attenuation and complex extraction by signal injection method.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] In a first aspect, a permeability modulation excitation generator including main motor rotor position information is provided, wherein the excitation generator is a rotating armature structure, and the rotor in the excitation generator is a hidden pole slot structure, and a three-phase symmetrical armature winding is placed in the slot; the armature winding of the excitation generator is connected to a rotating rectifier to provide pulsating direct current to the main motor, and the two (excitation generator and main motor) are coaxially connected and have the same mechanical rotation speed;

[0008] The rotor profile of the excitation generator adopts an eccentric circle to construct a salient pole permeability modulation structure, with p Λ The stator and rotor have salient poles to form an uneven air gap between them.

[0009] Furthermore, the number of the salient pole permeability modulation structures of the excitation generator is not equal to the number of poles of the excitation generator.

[0010] Furthermore, the excitation generator rotor is coaxially mounted with the main motor rotor, the main motor is an electrically excited salient pole synchronous motor, and the salient pole permeance modulation structure number p of the excitation generator rotor is Λ The number of poles of the main motor is p m Half of the rotor position information can be demodulated by extracting the stator current response of the excitation generator.

[0011] Furthermore, the stator of the excitation generator is a salient pole structure, and two symmetrical concentrated windings α phase and β phase are embedded in the slots, and the phase difference between the two (α phase and β phase) in the axis space is 90° electrical angle;.

[0012] 5. The permeability modulation excitation generator containing the main motor rotor position information according to claim 4 is characterized in that each phase of the two symmetrical excitation windings is connected in parallel using multiple branches. When the number of parallel branches is 4 times the number of pole pairs of the exciter, the permeability change of the magnetic circuit caused by the rotor salient pole permeability modulation structure is reflected in the current signal on the stator side of the excitation generator.

[0013] In a second aspect, a rotor position information mediation method of a magnetic permeability modulation excitation generator including main motor rotor position information comprises:

[0014] Step 1, extracting the excitation current of a branch of the permeability modulation excitation generator containing the main motor rotor position information, and using an amplitude demodulation method to demodulate an envelope containing the rotor position information;

[0015] Step 2: Use the inverse transformation of trigonometric functions to obtain the position angle of the magnetic permeability modulation structure of the excitation generator rotor, and calculate the main motor rotor position information.

[0016] Furthermore, the step 1 comprises:

[0017] The air gap length corresponding to the salient pole profile of the excitation generator rotor can be expressed as:

[0018]

[0019] Among them, R s ——radius of the inner surface of the stator;

[0020] H——eccentricity;

[0021] R p ——radius of eccentric circle;

[0022] θ Λ ——Angular position of a point A on the rotor surface in the polar coordinate system

[0023] r——The radius of a point A on the rotor surface in the polar coordinate system;

[0024] When AC voltage is applied to the excitation winding of the excitation generator, an excitation current will be induced in the excitation winding. Taking a branch current can reflect the current response of the change in magnetic permeance. The excitation voltage of the given α-phase winding is expressed as

[0025]

[0026] Among them, U rms ——effective value of excitation voltage;

[0027] ω exf ——excitation angular frequency of the excitation generator;

[0028] t——time;

[0029] Since the excitation frequency is high enough, the reactance of the excitation generator is much larger than the excitation resistance, that is, ω exf L f >>R f , the excitation resistance part can be ignored in the current response expression, so the excitation response current i of one branch of the excitation winding is α1 It can be expressed as

[0030]

[0031] Among them, u α ——excitation voltage of α-phase winding;

[0032] X f ——high frequency excitation reactance;

[0033] L f ——magnetizing inductance;

[0034] Since the excitation winding inductance of the excitation generator can be expressed as

[0035]

[0036] Among them, N f ——Number of turns of excitation winding of exciter;

[0037] Λ f ——Magnetic permeability of the magnetic circuit of the excitation generator;

[0038] Therefore, it can be explained that the larger the permeance, the smaller the excitation inductance, which in turn explains that the excitation current response amplitude is smaller, so the excitation current response amplitude will change with the change of permeance;

[0039] The magnetic permeance of the magnetic circuit can be expressed as

[0040] Λ f =μ / δ(θ Λ )

[0041] Among them, μ is the magnetic permeability, which is a constant;

[0042] It can be shown that the magnetic circuit permeance is negatively correlated with the air gap length. Substituting this formula into the current response expression can show the direct relationship between the current response and the rotor position angle of the excitation generator;

[0043]

[0044] The above formula can be simplified to

[0045]

[0046] Among them, k h ——Amplitude of excitation current.

[0047] The technical solution adopted by the present invention has the following beneficial effects:

[0048] 1. Compared with the multi-stage motor low-speed section position-free control method that requires signal transmission, the magnetic permeability modulation excitation generator structure that contains the main motor rotor position information is designed, and at the same time, the structural characteristics of the three-stage synchronous motor are utilized. The rotor position detection is performed by extracting the modulation wave of the stator excitation current of the excitation generator after the magnetic permeability modulation of the salient pole rotor structure. The response speed is fast, the harmonic interference is small, and the signal extraction is convenient.

[0049] 2. The present invention enables the starting process of the aviation three-stage starter / generator to have good position estimation accuracy in the low-speed section, can meet the starting requirements of the main motor, and provides a new method for the aviation three-stage starter / generator position-free control technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 It is a schematic diagram of the structure of the magnetic permeability modulation excitation generator containing the main motor rotor position information of the present invention;

[0051] Figure 2It is a simplified structural schematic diagram of the non-uniform air gap of the permeability modulation excitation generator containing the main motor rotor position information of the present invention;

[0052] Figure 3 This is the simulated waveform of the stator current of phase A1 of the exciter obtained at a speed of 600r / min;

[0053] Figure 4 It is a simulation waveform diagram of the rotor position demodulation result based on the rotor structure of the magnetic permeability modulation excitation generator which contains the main motor rotor position information.

[0054] 1. α-phase excitation winding; 2. β-phase excitation winding; 3. Stator; 4. Three-phase armature winding; 5. Rotor; 6. Maximum air gap; 7. Minimum air gap; 8. Inner diameter R of excitation generator stator s ; 9. Excitation generator rotor outer diameter R r ; 10. Eccentricity H of rotor salient pole structure; 11. Angle θ corresponding to any point A of the salient pole profile of the excitation generator rotor Λ ; 12. Radius of rotor eccentric circle R p ; 13. The radius r corresponding to any point A on the salient pole contour of the excitation generator rotor. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0056] In order to solve the difficulty of detecting the rotor position of a three-stage starter / generator at a low speed and improve the detection accuracy of the rotor position of a three-stage starter / generator at a low speed, the present invention proposes a magnetic permeability modulation excitation generator including direct rotor position information of the main motor.

[0057] A permeability modulation excitation generator containing the main motor rotor position information, the excitation generator is a rotating armature structure, its rotor is a hidden pole slot structure, and a three-phase symmetrical armature winding is placed in the slot. The armature winding of the excitation generator is connected to the rotating rectifier to provide pulsating direct current to the main motor. The two are coaxially connected and have the same mechanical speed. The rotor profile of the permeability modulation excitation generator containing the main motor rotor position information adopts an eccentric circle to construct a salient pole permeability modulation structure, with p Λ There are salient poles, which form an uneven air gap between the stator and the rotor. Since the radial expansion diagram of the rotor outer surface is a periodic full-wave function, it can cause periodic changes in spatial magnetic permeability.

[0058] In this embodiment, the number of salient pole permeability modulation structures of the permeability modulation excitation generator containing the main motor rotor position information is inconsistent with the number of exciter poles, which will not cause average torque, etc., and damage the motor output performance.

[0059] In the embodiment of the present invention, the magnetic permeability modulation excitation generator rotor containing the main motor rotor position information is coaxially installed with the main motor rotor, and the excitation generator rotor must be able to reflect the rotor position characteristics of the main motor. The main motor is generally a traditional electrically excited salient pole synchronous motor, and the number of salient pole magnetic permeability modulation structures of the excitation generator rotor is p. Λ The number of poles of the main motor is p m to realize the polarity judgment of the main motor.

[0060] In this embodiment, two symmetrical concentrated windings α and β are embedded in the stator slots of the permeability modulation excitation generator containing the main motor rotor position information, and the phase difference between the two axial spaces is 90° electrical angle. Each phase of the two symmetrical excitation windings can be completely connected in series or multiple branches can be connected in parallel. However, when the windings of each branch of the two phases are connected in parallel, and the number of parallel branches is 4 times the number of exciter pole pairs, the permeability change of the magnetic circuit caused by the rotor salient pole permeability modulation structure can be reflected in the current signal on the stator side of the permeability modulation excitation generator containing the main motor rotor position information, and at the same time, it can meet the excitation requirements of the main motor for power generation and starting.

[0061] Among them, as the rotor of the permeability modulation excitation generator containing the main motor rotor position information rotates relative to the stator, the spatial permeability will change periodically due to the salient pole characteristics of the rotor. Every time the rotor rotates one tooth pitch, the spatial permeability completes a cycle of changes, causing the flux in the stator winding of the excitation generator to also change periodically, thereby inducing a periodic current related to the rotor position in the excitation winding. When the rotor completes one rotation, the stator-side excitation current will undergo a periodic change equal to the number of rotor salient poles, so it includes the salient pole rotor position of the excitation generator, and can then reflect the main motor rotor position.

[0062] In this embodiment, a rotor position information mediation method of a permeability modulation excitation generator containing the main motor rotor position information is provided: the excitation current of a branch of the permeability modulation excitation generator containing the main motor rotor position information is extracted, an amplitude demodulation method is used to demodulate an envelope containing the rotor position information, and a trigonometric function inverse transformation is used to obtain the position angle of the permeability modulation structure of the excitation generator rotor, so as to directly calculate the main motor rotor position angle.

[0063] The present invention is further explained below in conjunction with the accompanying drawings and specific examples:

[0064] according to Figure 2The simplified structural diagram of the non-uniform air gap of the excitation generator is shown in FIG. The air gap length corresponding to the salient pole profile of the excitation generator rotor can be expressed as:

[0065]

[0066] Among them, R s ——radius of the inner surface of the stator;

[0067] H——eccentricity;

[0068] R p ——radius of eccentric circle;

[0069] θ Λ ——Angular position of a point A on the rotor surface in the polar coordinate system

[0070] r is the radius of a point A on the rotor surface in the polar coordinate system.

[0071] When an AC voltage is applied to the excitation winding of the excitation generator, an excitation current will be induced in the excitation winding. Taking a branch current can reflect the current response of the change in magnetic permeability. The excitation voltage of the given α-phase winding is expressed as

[0072]

[0073] Among them, U rms ——effective value of excitation voltage;

[0074] ω ex f——excitation angular frequency of the excitation generator;

[0075] t——time.

[0076] Since the excitation frequency is high enough, the reactance of the excitation generator is much larger than the excitation resistance, that is, ω exf L f >>R f , the excitation resistance part can be ignored in the current response expression, so the excitation response current i of one branch of the excitation winding is α1 It can be expressed as

[0077]

[0078] Among them, u α ——excitation voltage of α-phase winding;

[0079] X f ——high frequency excitation reactance;

[0080] L f ——Magnetic inductance.

[0081] Since the excitation winding inductance of the excitation generator can be expressed as

[0082]

[0083] Among them, N f ——Number of turns of excitation winding of exciter;

[0084] Λ f ——Magnetic permeability of the magnetic circuit of the excitation generator;

[0085] Therefore, it can be explained that the larger the magnetic permeability, the smaller the excitation inductance, which further explains that the excitation current response amplitude is smaller, so the excitation current response amplitude will change with the change of magnetic permeability.

[0086] The magnetic permeance of the magnetic circuit can be expressed as

[0087] Λ f =μ / δ(θ Λ )

[0088] Among them, μ is the magnetic permeability, which is a constant;

[0089] It can be shown that the magnetic circuit permeability is negatively correlated with the air gap length. Substituting this formula into the current response expression can show the direct relationship between the current response and the rotor position angle of the excitation generator.

[0090]

[0091] The above formula can be simplified to

[0092]

[0093] Among them, k h ——Excitation current amplitude

[0094] Therefore, it can be seen from the above formula that the excitation current of one branch of the exciter can be extracted, the envelope containing the rotor position information can be demodulated using the amplitude demodulation method, the position angle of the excitation generator rotor magnetic permeability modulation structure can be obtained using the inverse transformation of trigonometric functions, and then the main motor rotor position angle can be calculated.

[0095] Figure 1 It is a structural schematic diagram of a magnetic permeability modulation excitation generator containing main motor rotor position information, which includes an α-phase excitation winding 1, a β-phase excitation winding 2, a stator 3, a three-phase armature winding 4, a rotor 5, a maximum air gap 6, and a minimum air gap 7.

[0096] The excitation generator is a rotating armature motor, and the α-phase excitation winding 1 and the β-phase excitation winding 2 are embedded in the slots of the stator 3, and each phase is connected in parallel. When the excitation power supply provides two-phase orthogonal excitation voltage, a circular rotating magnetic field is formed, and at this time, the three-phase armature winding 4 embedded in the slots of the rotor 5 outputs three-phase alternating current. The non-uniform air gap formed based on the maximum air gap 6 and the minimum air gap 7 will cause the magnetic permeance of the magnetic circuit of the excitation generator to change, thereby causing the current amplitude in the α-phase excitation winding 1 and the β-phase excitation winding 2 to change.

[0097] Figure 2 The present invention includes a simplified structural diagram of a non-uniform air gap of a magnetic permeability modulation excitation generator containing the main motor rotor position information, which includes 8 excitation generator stator inner diameter R s , 9 Excitation generator rotor outer diameter R r , 10 Eccentricity H of rotor salient pole structure, 11 Angle θ corresponding to any point A of the salient pole profile of the excitation generator rotor Λ , 12 rotor eccentric circle radius R p , 13 The radius r corresponding to any point A on the salient pole contour of the excitation generator rotor.

[0098] Figure 3 The simulated waveform of the stator current of phase A1 of the excitation generator obtained at a speed of 600r / min. It can be seen from the figure that in one mechanical cycle of the excitation generator, the rotor salient pole structure will cause the magnetic permeability of the excitation generator magnetic circuit to change, which will in turn cause the envelope amplitude of the excitation current response of a single branch of the stator excitation winding of the excitation generator to change. The number of envelope cycles is related to the number of rotor salient poles p. Λ The amplitude demodulation method is used to demodulate the rotor position information of its positive envelope, and the rotor position of the main motor can be detected according to the corresponding relationship between the coaxially installed rotors of the main motor and the excitation generator.

[0099] Figure 4 It is a simulated waveform diagram of the rotor position demodulation result of the magnetic permeability modulation excitation generator rotor structure containing the main motor rotor position information. It can be seen that when the motor speed is given to be 600r / min, the method proposed by the present invention makes the average value of the rotor position error close to zero, with only a small pulsation, and the estimated effect number, and the error is stable within 0.03rad. According to the indicator that the rotor position estimation error of a general three-stage generator must be within 0.175rad for the successful completion of load starting, the method proposed by the present invention can achieve the smooth load starting of the main motor.

[0100] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the schemes disclosed herein. The present invention is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed in this disclosure. The description and examples are to be considered exemplary only, and the true scope and spirit of the present invention are indicated by the claims.

Claims

1. A permeability modulation excitation generator including main motor rotor position information, characterized in that: The excitation generator is a rotating armature structure, and the rotor in the excitation generator is a hidden pole slot structure, with three-phase symmetrical armature windings placed in the slots; the armature winding of the excitation generator is connected to the rotating rectifier to provide pulsating DC power to the main motor. The excitation generator and the main motor are coaxially connected, and the mechanical speed is consistent; The rotor profile of the excitation generator adopts an eccentric circle to construct a salient pole permeability modulation structure, with p Λ The stator and rotor have salient poles to form an uneven air gap between them.

2. The permeability modulated excitation generator containing the main motor rotor position information according to claim 1, characterized in that: The number of the salient pole permeability modulation structures of the excitation generator is not equal to the number of poles of the excitation generator.

3. The permeability modulation excitation generator containing the main motor rotor position information according to claim 1, characterized in that: The excitation generator rotor is coaxially mounted with the main motor rotor. The main motor is an electrically excited salient pole synchronous motor. The salient pole permeability modulation structure number p of the excitation generator rotor is Λ The number of poles of the main motor is p m Half of the rotor position information can be demodulated by extracting the stator current response of the excitation generator.

4. The permeability modulation excitation generator containing the main motor rotor position information according to claim 1, characterized in that: The stator of the excitation generator is a salient pole structure, and two symmetrical concentrated windings of phase α and phase β are embedded in the slots. The phase difference between the α and β phases in the axis space is 90° electrical angle.

5. The permeability modulation excitation generator containing the main motor rotor position information according to claim 4, characterized in that: Each phase of the two symmetrical excitation windings is connected in parallel using multiple branches. When the number of parallel branches is 4 times the number of pole pairs of the exciter, the change in magnetic circuit permeability caused by the rotor salient pole permeability modulation structure is reflected in the current signal on the stator side of the excitation generator.

6. A rotor position information mediation method for a permeability modulation excitation generator including main motor rotor position information as claimed in claim 1, characterized in that: include: Step 1, extracting the excitation current of a branch of the permeability modulation excitation generator containing the main motor rotor position information, and using an amplitude demodulation method to demodulate an envelope containing the rotor position information; Step 2: Use the inverse transformation of trigonometric functions to obtain the position angle of the magnetic permeability modulation structure of the excitation generator rotor, and calculate the main motor rotor position information.

7. The rotor position information mediation method of the permeability modulation excitation generator containing the main motor rotor position information according to claim 6, characterized in that: The step 1 comprises: The air gap length corresponding to the salient pole profile of the excitation generator rotor can be expressed as: Among them, R s ——radius of the inner surface of the stator; H——eccentricity; R p ——radius of eccentric circle; θ Λ ——Angular position of a point A on the rotor surface in the polar coordinate system r——The radius of a point A on the rotor surface in the polar coordinate system; When AC voltage is applied to the excitation winding of the excitation generator, an excitation current will be induced in the excitation winding. Taking a branch current can reflect the current response of the change in magnetic permeance. The excitation voltage of the given α-phase winding is expressed as Among them, U rms ——effective value of excitation voltage; ω exf ——excitation angular frequency of the excitation generator; t——time; Since the excitation frequency is high enough, the reactance of the excitation generator is much larger than the excitation resistance, that is, ω exf L f >>R f , the excitation resistance part can be ignored in the current response expression, so the excitation response current i of one branch of the excitation winding is α1 It can be expressed as Among them, u α ——excitation voltage of α-phase winding; X f ——high frequency excitation reactance; L f ——magnetizing inductance; Since the excitation winding inductance of the excitation generator can be expressed as Among them, N f ——Number of turns of excitation winding of exciter; Λ f ——Magnetic permeability of the magnetic circuit of the excitation generator; Therefore, it can be explained that the larger the permeance, the smaller the excitation inductance, which in turn explains that the excitation current response amplitude is smaller, so the excitation current response amplitude will change with the change of permeance; The magnetic permeance of the magnetic circuit can be expressed as L f =μ / δ(θ Λ ) Among them, μ is the magnetic permeability, which is a constant; It can be shown that the magnetic circuit permeance is negatively correlated with the air gap length. Substituting this formula into the current response expression can show the direct relationship between the current response and the rotor position angle of the excitation generator; The above formula can be simplified to Among them, k h ——Amplitude of excitation current.

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