Rotor position estimation method under initial turn-to-turn short circuit of aviation permanent magnet starter generator

Abstract

The invention discloses a rotor position estimation method under initial turn-to-turn short circuit of an aviation permanent magnet starter generator, and the method specifically comprises the steps: obtaining a correlation formula when a permanent magnet synchronous motor is in a healthy state and a turn-to-turn short circuit fault occurs; on the basis of the turn-to-turn short circuit fault, voltage and current are obtained; inputting the three-phase current and voltage into a sliding-mode observer after the three-phase current and voltage are subjected to Click conversion to obtain back electromotive force; the back electromotive force is filtered, the positive sequence component is extracted, the fundamental wave back electromotive force is obtained, and accurate rotor position information can be estimated through a phase-locked loop. According to the method, when the aviation permanent magnet starter generator is operated in a power generation state without a position sensor, harmonic interference generated by a motor turn-to-turn short circuit fault is separated by designing a high-order generalized integrator, so that a positive sequence component in a fundamental wave back electromotive force estimated value is accurately obtained and is used for rotor position estimation after the turn short circuit fault occurs; the magnetic field orientation deviation caused by the turn short fault is eliminated, and the optimal fault feature extraction environment is ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of AC motor control, and particularly relates to a method for estimating the rotor position under the initial turn-to-turn short circuit of an aviation permanent magnet starting generator. Background Art

[0002] A permanent magnet synchronous generator (PMSG) is a high-performance AC synchronous motor. Its permanent magnet excitation design makes it have the characteristics of low pollution, high efficiency, high practicability, etc., so it is widely used in various advanced intelligent manufacturing equipment, modern industrial production, aerospace and other fields. Especially in modern aviation flight systems, the permanent magnet starting generator not only serves as a starting device to provide necessary power for the engine during the ground starting stage, but also works as a generator to supply power to the aircraft during the flight stage of the aircraft. Existing aviation permanent magnet starting power generation systems usually use mechanical position / velocity sensors to obtain the position signal or rotational speed signal of the motor. However, during the actual operation of the aircraft, the electromagnetic environment is complex and the vibration is intense, which easily causes the mechanical sensor to fail, thus triggering traction system failures. In severe cases, it may damage key components such as bearings, gears, and motors, threatening flight safety. The sensorless drive technology can fundamentally eliminate this safety hazard and has the advantages of strong anti-interference ability, high integration, and long service life.

[0003] During flight, the PMSG often faces harsh conditions such as high temperature, high humidity, and strong vibration. These factors increase the probability of turn-to-turn short circuit faults. When such a fault occurs, it is manifested as an abnormal short-circuit current formed between different wire turns in the same phase of the stator winding due to the damage of the insulating material, resulting in uneven current distribution, seriously affecting the performance and reliability of the PMSG. If not dealt with in time, the high cyclic current generates overheat, and the overheat causes the current to deteriorate and trigger a chain reaction, promoting the fault to gradually deteriorate into more serious interphase short circuit or open phase problems, and ultimately may lead to catastrophic consequences. The occurrence of turn-to-turn short circuit will directly cause three-phase asymmetry. The introduced negative sequence component will deteriorate the input current signal of the position observer, causing deviation in magnetic field orientation, resulting in deviation in rotor position estimation, and decreasing the accuracy of turn-to-turn short circuit fault diagnosis. Therefore, if the misdiagnosis caused by the magnetic field orientation deviation can be eliminated and the rotor position of the motor can be accurately estimated after the turn short fault occurs when the permanent magnet starting generator is operating in the power generation state, the reliable diagnosis of the motor turn-to-turn short circuit fault can be ensured. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for estimating the rotor position under the initial turn-to-turn short circuit of an aviation permanent magnet starting generator, suppressing the harmonic signal interference caused by the turn-to-turn short circuit fault state of the motor, and improving the accuracy of turn-to-turn short circuit fault diagnosis.

[0005] The technical solution adopted by the present invention is a method for estimating the rotor position under the initial turn-to-turn short circuit of an aviation permanent magnet starting generator, which is specifically implemented according to the following steps: Step 1: Obtain the relevant formulas when the permanent magnet synchronous motor is in a healthy state and when a turn-to-turn short circuit fault occurs; Step 2: Based on the turn-to-turn short circuit fault, obtain the voltages and currents of the d-axis and q-axis, and use a sliding mode observer control to achieve the estimation of the rotor position under the fault condition; Step 3: Extract the three-phase voltages and three-phase currents in the natural coordinate system of the permanent magnet synchronous generator, and input the three-phase currents and three-phase voltages into the sliding mode observer after Clack transformation to obtain the back electromotive forces under the d-axis and q-axis; Step 4: Filter the back electromotive force to obtain the back electromotive forces E_d and E_q; and axis back electromotive force; Step 5: Extract the positive sequence components of the back electromotive force from E_d and E_q to obtain the fundamental wave back electromotive forces E_d1 and E_q1, and then the accurate rotor position information can be estimated through a phase-locked loop. and ; Step 6: Extract the positive sequence component of the back electromotive force from E_d and E_q to obtain the fundamental wave back electromotive force E_d1 and E_q1, and then the accurate rotor position information can be estimated through a phase-locked loop. and to obtain the fundamental back electromotive force and , and then the accurate rotor position information can be estimated through a phase-locked loop.

[0006] The characteristics of the present invention also lie in that In step 1, specifically: Step 1.1: When the permanent magnet synchronous generator is in a healthy state, the direct-axis and quadrature-axis voltage equations of the permanent magnet synchronous generator in the rotating coordinate system are shown in Equation (1), and the direct-axis and quadrature-axis flux linkage equations are shown in Equation (2): (1); (2); Substitute Equation (2) into Equation (1) to obtain the stator voltage equation, as shown in Equation (3): (3) In the formula, is the direct-axis voltage, is the quadrature-axis voltage, is the direct-axis current, is the quadrature-axis current, is the direct-axis inductance, is the quadrature-axis inductance, is the direct-axis flux linkage, is the quadrature-axis flux linkage, is the stator resistance, is the electrical angular velocity, is the permanent magnet flux linkage; Step 1.2, when one phase of the permanent magnet synchronous generator is a faulty phase and the motor has a turn-to-turn short circuit fault, the direct-axis and quadrature-axis voltage equations of the permanent magnet synchronous generator in the turn-to-turn short circuit fault state are shown in Equation (4); (4); wherein, is the direct-axis voltage of the permanent magnet synchronous generator in the turn-to-turn short circuit fault state; is the quadrature-axis voltage of the permanent magnet synchronous generator in the turn-to-turn short circuit fault state; and are the measured currents of the permanent magnet synchronous generator on the d axis and q axis in the turn-to-turn short circuit fault state, as shown in Equation (5); (5); wherein, is the ratio of the number of shorted turns to the total number of turns, is the electrical angle of the rotor of the permanent magnet synchronous motor; i f is the short-circuit current.

[0007] i f The calculation formula of (6); wherein, is the phase-a voltage, is the short-circuit resistance; is the neutral point voltage, and the calculation formula is shown in Equation (7): (7); wherein, L is the inductance.

[0008] In Step 2, specifically: Perform Park transformation on and to obtain three-phase currents, as shown in Equation (8): (8); wherein, , and are the three-phase currents when the permanent magnet synchronous generator has a turn-to-turn short circuit, is the zero-sequence component of the current; Extract the three-phase currents and three-phase voltages in the turn-to-turn short circuit state of the permanent magnet synchronous generator, and after Clark transformation, obtain axis, axis voltages and currents , making it the input of the sliding mode observer, as shown in Equations (9) and (10); (9); (10); Wherein, u a , u b , u c are the voltages of phase a, phase b, and phase c, respectively.

[0009] In Step 3, specifically: Step 3.1, perform the inverse Park coordinate transformation on Equation (1), to obtain the voltage equation of the PMSG rectifier system in the stationary coordinate system, as shown in Equation (11); (11); In the formula, is the axis back electromotive force; is the axis back electromotive force; is the axis voltage; is the axis voltage; , The calculation formulas of are as shown in Equation (12); Step 3.2, construct a sliding mode observer, input the three-phase current and three-phase voltage into the sliding mode observer after the Clack transformation, to obtain and the back electromotive forces under the The sliding mode observer is as shown in Equation (13): (13); In the formula, wherein, , is the , axis current observed values, , are the , derivatives of the , are the and axis back electromotive forces, as shown in Equation (14):; (14); In the formula,k is the sliding mode gain, and sgn is the sign function.

[0010] sgn is expressed as Equation (15): (15).

[0011] In step 4, specifically: the back electromotive force of the axis component is processed and the axis back electromotive force signal and the lagging back electromotive force signal are output; at the same time, the back electromotive force of the axis component is processed by using the high-order generalized integrator HOGI and the axis component back electromotive force signal and the back electromotive force signal lagging by 90° are output, as shown in Equation (16): (16); where and are respectively the axis back electromotive force signal estimated by HOGI and the back electromotive force lagging ; and are respectively the axis back electromotive force signal estimated by HOGI and the back electromotive force lagging ; is the Laplace operator, K 1 and K 2 are the gain coefficients of HOGI, is the fundamental wave frequency input to the high-order generalized integrator.

[0012] In step 5, specifically: the positive sequence components and of the fundamental back electromotive force are extracted after filtering by HOGI, as shown in Equation (17): (17) where and are respectively the axis back electromotive force signal estimated by HOGI and the back electromotive force lagging ; and are respectively the axis back electromotive force signal estimated by HOGI and the back electromotive force lagging ; after obtaining its back electromotive force, the rotor position information is extracted from the back electromotive force by using a phase-locked loop.

[0013] The beneficial effects of the present invention are as follows: In the method of the present invention, when the aviation permanent magnet starting generator operates in the power generation state without a position sensor, the high-order generalized integrator (HOGI) is designed to separate the harmonic interference generated by the inter-turn short circuit fault of the motor, so as to accurately obtain the positive sequence component in the fundamental back electromotive force estimation value, which is used for the rotor position estimation after the inter-turn short circuit fault occurs, eliminate the magnetic field orientation deviation caused by the inter-turn short circuit fault, and ensure the optimal environment for fault feature extraction. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is the principle block diagram of the rotor position estimation method for the initial inter-turn short circuit of the aviation permanent magnet starting generator of the present invention; Figure 2 is the schematic diagram of the principle of the high-order generalized integrator (HOGI) of the present invention; Figure 3 is the schematic diagram of the extraction principle of the positive sequence component of the present invention; Figure 4 is the comparison diagram of the three-phase current waveforms before and after the inter-turn short circuit occurs; Figure 5 is the FFT analysis diagram of the fundamental back electromotive force extracted by the high-order generalized integrator under the healthy state of the permanent magnet synchronous generator; Figure 6 is the FFT analysis diagram of the fundamental back electromotive force extracted by the traditional sliding mode observer under the healthy state of the permanent magnet synchronous generator; Figure 7 is the FFT analysis diagram of the fundamental back electromotive force extracted by the high-order generalized integrator after the inter-turn short circuit fault occurs in the permanent magnet synchronous generator; Figure 8 is the FFT analysis diagram of the fundamental back electromotive force extracted by the traditional sliding mode observer after the inter-turn short circuit fault occurs in the permanent magnet synchronous generator; Figure 9 is the comparison diagram of the true rotor position and the estimated rotor position after the high-order generalized integrator when the inter-turn short circuit fault occurs; Figure 10 is the comparison diagram of the true rotor position and the estimated rotor position after the traditional sliding mode observer when the inter-turn short circuit fault occurs; Figure 11 is the rotor position estimation angle error diagram generated by the high-order generalized integrator when the inter-turn short circuit fault occurs; Figure 12 is the rotor position estimation angle error diagram generated by the traditional sliding mode observer when the inter-turn short circuit fault occurs. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0015] The present invention will be described in detail below in conjunction with the specific embodiments and the drawings.

[0016] Example 1 The rotor position estimation method of the aviation permanent magnet starting generator of the present invention under the initial turn - to - turn short - circuit is as follows Figure 1 shown, and is specifically implemented according to the following steps: Step 1: Based on the permanent magnet synchronous generator model, analyze the fault principle of turn - to - turn short - circuit of the permanent magnet synchronous motor to obtain the relevant formulas for turn - to - turn short - circuit faults; specifically: Step 1.1: When the permanent magnet synchronous generator is in a healthy state, the direct - axis and quadrature - axis voltage equations of the permanent magnet synchronous generator in the rotating coordinate system are as shown in Equation (1), and the direct - axis and quadrature - axis flux - linkage equations are as shown in Equation (2): (1); (2); Substitute Equation (2) into Equation (1) to obtain the stator voltage equation, as shown in Equation (3): (3) In the formula, is the direct - axis voltage, is the quadrature - axis voltage, is the direct - axis current, is the quadrature - axis current, is the direct - axis inductance, is the quadrature - axis inductance, is the direct - axis flux - linkage, is the quadrature - axis flux - linkage, is the stator resistance, is the electrical angular velocity, is the permanent - magnet flux - linkage.

[0017] Step 1.2: When one phase of the permanent magnet synchronous generator is a fault phase and the motor has a turn - to - turn short - circuit fault, the direct - axis and quadrature - axis voltage equations of the permanent magnet synchronous generator in the turn - to - turn short - circuit fault state are as shown in Equation (4); (4); In the formula, is the direct - axis voltage of the permanent magnet synchronous generator in the turn - to - turn short - circuit fault state; is the quadrature - axis voltage of the permanent magnet synchronous generator in the turn - to - turn short - circuit fault state; and are the measured currents of the permanent magnet synchronous generator on the d axis and q axis in the turn - to - turn short - circuit fault state, as shown in Equation (5); (5); In the formula, is the ratio of the short - circuited turns to the total turns, is the electrical angle of the rotor of the permanent magnet synchronous motor, if is the short - circuit current.

[0018] i f The calculation formula of is as shown in Equation (6): (6); In the formula, is the phase - a voltage, is the short - circuit resistance; is the neutral - point voltage, and its calculation formula is as shown in Equation (7): (7); In the formula, L is the inductance; When a turn - to - turn short - circuit fault occurs, it can be deduced from Equations (4) and (5) that the turn - to - turn short - circuit fault will affect the stator voltage and current of the permanent - magnet synchronous generator, resulting in asymmetry of the three - phase stator windings of the permanent - magnet generator; Step 2, on the basis of the turn - to - turn short - circuit fault, obtain the voltage and current of the axis and the axis, and use sliding - mode observer control to realize the rotor - position estimation under fault conditions; specifically: and are subjected to Park transformation to obtain the three - phase current, as shown in Equation (8): (8); Among them, , and are the three - phase currents of the permanent - magnet synchronous generator when a turn - to - turn short - circuit occurs, is the zero - sequence component of the current; Extract the three - phase current and three - phase voltage of the permanent - magnet synchronous generator under the turn - to - turn short - circuit state. After Clark transformation, obtain the voltage and current under the axis and the (9); (10); Among them, u a , u b , u c are the voltages of phase - a, phase - b, and phase - c respectively; Step 3: Extract the three-phase voltage and three-phase current in the natural coordinate system of the permanent magnet synchronous generator. After the three-phase current and three-phase voltage are subjected to the Clack transformation, they are input into the sliding mode observer to obtain and the back electromotive force under the axis; specifically: (11); In the formula, is the axis back electromotive force, with the unit of V; is the axis back electromotive force, with the unit of V; is the axis voltage; is the axis voltage; , The calculation formulas of are shown in formula (12); (12); It can be seen from the above formula that accurately estimating the components of the back electromotive force on the , axis can extract the rotor position information.

[0019] Step 3.2: Construct a sliding mode observer. After the three-phase current and three-phase voltage are subjected to the Clack transformation, they are input into the sliding mode observer to obtain and the back electromotive force under the axis; The sliding mode observer is shown in formula (13): (13); In the formula, where , is the , axis current observation value, , are the , axis current derivatives with respect to time; , are the and axis back electromotive forces, as shown in formula (14):; (14); In the formula, k is the sliding mode gain, and sgn is the sign function, expressed as formula (15): (15); Step 4: Design a high-order generalized integral (HOGI) to filter the back electromotive force obtained in Step 3 to obtain the back electromotive force and ; After the system stabilizes, the estimated back electromotive force component is obtained according to Equation (14). However, due to the non-linear characteristic of the sign function, the system will chatter near the sliding mode surface s = 0, resulting in high-order harmonics in the estimated back electromotive force.

[0020] As Figure 2 shown, the back electromotive force of the axis component is processed by a high-order generalized integrator (HOGI) and then outputs the axis back electromotive force signal and the back electromotive force signal lagging . At the same time, the back electromotive force of the axis component is processed by a high-order generalized integrator (HOGI) and then outputs the axis component back electromotive force signal and the back electromotive force signal lagging . By utilizing the multiple feedback filtering characteristic of the high-order generalized integrator (HOGI), the performance of the observer is further improved, as shown in Equation (16): (16); Wherein, and are respectively the axis back electromotive force signal estimated by HOGI and the back electromotive force lagging , and are respectively the axis back electromotive force signal estimated by HOGI and the back electromotive force lagging , is the Laplace operator, K 1 and K 2 are the gain coefficients of HOGI, is the fundamental wave frequency input to the high-order generalized integrator.

[0021] Step 5: Extract the positive sequence component of the back electromotive force from and to obtain the fundamental wave back electromotive force and . The accurate rotor position information can be estimated by using the fundamental wave back electromotive force information through a phase-locked loop.

[0022] Example 2 Furthermore, in Step 5, specifically: AsFigure 3 As shown, the positive sequence component of the fundamental back electromotive force is extracted after HOGI filtering and , as shown in Equation (17): (17) where and are respectively the axis back electromotive force signal estimated by HOGI and the back electromotive force lagging behind ; and are respectively the axis back electromotive force signal estimated by HOGI and the back electromotive force lagging behind ; After obtaining its back electromotive force, a phase locked loop (PLL) is used to extract the rotor position information from the back electromotive force.

[0023] Example 3 There is an error between the actual rotor position and the estimated rotor position, and the expression of its angular error is as shown in Equation (18): (18) In the formula, is the estimated rotor position. The method of the present invention uses HOGI to improve the rotor position estimation accuracy when an inter-turn short circuit occurs in a permanent magnet synchronous generator, suppresses the harmonic signal interference caused by the inter-turn short circuit fault state of the motor, and helps to improve the accuracy of inter-turn short circuit fault diagnosis.

[0024] Example 4 When the permanent magnet starting generator is in the power generation state, the voltage is 270V, the motor speed is 1800r / min, and the number of pole pairs is 4, so when the fundamental frequency is 120Hz, an inter-turn short circuit fault occurs in phase A of the permanent magnet synchronous generator, and the short circuit turn ratio is 15%, and phases B and C are in a healthy state. Before and after the motor has an inter-turn short circuit fault, as Figure 4 shown, from 0.95 to 1s and from 0 to 1s, the motor is in a healthy state and the amplitudes of the three-phase currents are equal. From 1 to 1.15s, an inter-turn short circuit fault occurs in phase A, a short circuit loop appears in phase A, making the amplitude of phase A increase significantly, but its influence on the currents of phases B and C is small, resulting in unequal amplitudes of the ABC three-phase currents.

[0025] Example 5 Before the motor has an inter-turn short circuit fault, Figure 5 and Figure 6It is a comparison chart of the FFT harmonic analysis of the fundamental back electromotive force extracted by HOGI and the FFT harmonic analysis of the fundamental back electromotive force extracted based on the traditional sliding mode observer. When an inter-turn short circuit fault occurs in the motor, Figure 7 and Figure 8 It is a comparison chart of the FFT harmonic analysis of the fundamental back electromotive force extracted by HOGI and the FFT harmonic analysis of the fundamental back electromotive force extracted based on the traditional sliding mode observer. When an inter-turn short circuit fault occurs in a permanent magnet synchronous generator, the asymmetric current distribution in the stator winding will cause the distortion of the air-gap magnetic field, which in turn significantly enhances the 3rd and 5th harmonic components in the back electromotive force. Through the FFT analysis of the fault back electromotive force signal extracted by the sliding mode observer (SMO), the abnormal increase in the amplitudes of the 3rd and 5th harmonics can be clearly observed, as Figure 8 shown. Due to its inherent high-frequency chattering characteristics and insufficient harmonic suppression ability, the traditional SMO is difficult to accurately separate the fundamental component from the fault harmonics, which may affect the reliability of fault feature extraction. Therefore, the proposed harmonic suppression strategy based on the high-order generalized integrator (HOGI) is adopted, as Figure 7 shown. In the same fault scenario, the amplitudes of the 3rd and 5th harmonics in the back electromotive force spectrum output by HOGI are significantly reduced.

[0026] Example 6 When an inter-turn short circuit fault occurs in a permanent magnet synchronous generator, the local magnetic field distortion in the stator winding will cause a sharp increase in the harmonic components of the back electromotive force, resulting in significant fluctuations in the rotor position estimation results based on the sliding mode observer (SMO). As Figure 10 shown, the rotor position estimation error of the traditional SMO reaches its peak in the fault transient stage. The root cause is the sensitivity of the SMO to the 3rd and 5th harmonic components in the back electromotive force, which further affects the magnetic field orientation accuracy and even leads to the instability of the closed-loop control. The rotor position observation strategy is improved by using the high-order generalized integrator (HOGI), and a multi-band harmonic suppression channel is designed. HOGI can dynamically separate the fundamental back electromotive force from the fault harmonic components, significantly reducing the rotor position estimation fluctuations at the moment of the turn-to-turn short circuit fault, as Figure 9 shown; as Figure 11 and Figure 12 shown, in the same inter-turn short circuit condition, the rotor position estimation error of the SMO fluctuates significantly and the error is large. The error between the estimated rotor position after being processed by HOGI and the true rotor position is significantly reduced.

Claims

1. A method for estimating the rotor position of an aviation permanent magnet starter generator under initial turn-to-turn short circuit, characterized in that: Follow the steps below to implement it: Step 1, obtaining relevant formulas when the permanent magnet synchronous motor is in a healthy state and when a turn-to-turn short circuit fault occurs; Step 2: Based on the turn-to-turn short-circuit fault, we get axis, The voltage and current of the shaft are controlled by a sliding mode observer to achieve rotor position estimation under fault conditions; Step 3: extract the three-phase voltage and three-phase current of the permanent magnet synchronous generator in the natural coordinate system, and input the three-phase current and three-phase voltage into the sliding mode observer after Clack transformation to obtain and Back EMF under the shaft; Step 4: Filter the back EMF to obtain the back EMF and ; Step 5: Convert the positive sequence component of the back EMF from and Extract it and get the fundamental back EMF and , and then the accurate rotor position information can be estimated through the phase-locked loop.

2. The method for estimating rotor position of an aviation permanent magnet starter generator under initial turn-to-turn short circuit as claimed in claim 1, characterized in that: In the step 1, specifically: Step 1.1, when the permanent magnet synchronous generator is in a healthy state, the direct-axis and quadrature-axis voltage equations of the permanent magnet synchronous generator in the rotating coordinate system are shown in formula (1), and the direct-axis and quadrature-axis flux equations are shown in formula (2): （1）； （2）； Substituting equation (2) into equation (1), we can get the stator voltage equation, as shown in equation (3): （3） In the formula, is the direct axis voltage, is the quadrature axis voltage, is the direct axis current, is the quadrature axis current, is the direct-axis inductance, is the quadrature-axis inductance, is the direct axis flux, is the cross-axis flux, is the stator resistance, is the electrical angular velocity, is the permanent magnetic flux; Step 1.2, when one phase of the permanent magnet synchronous generator is a faulty phase, a turn-to-turn short circuit fault occurs in the motor. Then, the direct-axis and quadrature-axis voltage equations of the permanent magnet synchronous generator under the turn-to-turn short circuit fault state are as shown in equation (4); （4）； In the formula, is the direct-axis voltage of the permanent magnet synchronous generator under the inter-turn short-circuit fault state; is the quadrature axis voltage of the permanent magnet synchronous generator under the turn-to-turn short-circuit fault state; and It is a permanent magnet synchronous generator under the condition of inter-turn short circuit fault. d Axis and q The measured current of the shaft is shown in equation (5); （5）； In the formula, is the ratio of short-circuit turns to total turns, is the electrical angle of the permanent magnet synchronous motor rotor; i f is the short circuit current.

3. The method for estimating rotor position of an aviation permanent magnet starter generator under initial turn-to-turn short circuit as claimed in claim 2, characterized in that: i f The calculation formula is shown in formula (6): （6）； In the formula, is the voltage of phase a, is the short-circuit resistance; is the neutral point voltage, and the calculation formula is shown in formula (7): （7）； In the formula, L It's an inductor.

4. The method for estimating rotor position of an aviation permanent magnet starter generator under initial turn-to-turn short circuit as claimed in claim 2, characterized in that: In the step 2, specifically: Will and Perform Park transformation and get The three-phase current is shown in formula (8): （8）； in, , and is the three-phase current when the permanent magnet synchronous generator has a turn-to-turn short circuit, is the zero-sequence component of the current; The three-phase current and three-phase voltage of the permanent magnet synchronous generator under the inter-turn short-circuit state are extracted and obtained through Clark transformation. axis, Shaft voltage and current , so that it can be used as the input of the sliding mode observer, as shown in Equation (9) and Equation (10); （9）； （10）； in, u a , u b , u c They are the voltages of phase a, phase b, and phase c respectively.

5. The method for estimating rotor position of an aviation permanent magnet starter generator under initial turn-to-turn short circuit as claimed in claim 4, characterized in that: In the step 3, specifically: Step 3.1, perform inverse Park coordinate transformation on formula (1) to obtain the voltage equation of the PMSG rectifier system in the stationary coordinate system, as shown in formula (11); （11）； In the formula, for Shaft back EMF; for Shaft back EMF; for Shaft voltage; for Shaft voltage; , The calculation formula is shown in formula (12); （12）； Step 3.2, construct a sliding mode observer, input the three-phase current and three-phase voltage into the sliding mode observer after Clack transformation, and obtain and Back EMF under the shaft; The sliding mode observer is shown in formula (13): （13）； In the formula, , for , Observed shaft current, , for , The time derivative of the shaft current; , for and The back electromotive force under the shaft is shown in equation (14): （14）； In the formula, k is the sliding mode gain, and sgn is the sign function.

6. The method for estimating rotor position of an aviation permanent magnet starter generator under initial turn-to-turn short circuit as claimed in claim 5, characterized in that: sgn is expressed as formula (15): （15）。 7. The method for estimating the rotor position of an aviation permanent magnet starter generator under an initial turn-to-turn short circuit as claimed in claim 5, wherein in step 4, the method comprises: using a high-order generalized integrator HOGI to calculate The back electromotive force of the shaft component is processed and output Axis Back EMF Signal and Hysteresis The back electromotive force signal is obtained by using a high-order generalized integrator HOGI. The back electromotive force of the shaft component is processed and output The shaft component back electromotive force signal and the back electromotive force signal with a 90° lag are shown in equation (16): （16）； in, and They are estimated by HOGI Axis Back EMF Signal and Hysteresis The back electromotive force, and They are estimated by HOGI Axis Back EMF Signal and Hysteresis The back electromotive force, is the Laplace operator, K 1 and K 2 is the gain coefficient of HOGI, is the fundamental frequency of the high-order generalized integrator input.

8. The method for estimating the rotor position of an aviation permanent magnet starter generator under an initial turn-to-turn short circuit as claimed in claim 7, wherein the step 5 comprises: Extract the positive sequence component of the fundamental back EMF after HOGI filtering and , as shown in formula (17): （17） in, and They are estimated by HOGI Axis Back EMF Signal and Hysteresis The back electromotive force; and They are estimated by HOGI Axis Back EMF Signal and Hysteresis The back electromotive force; After obtaining its back electromotive force, a phase-locked loop is used to extract the rotor position information from the back electromotive force.

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