Secondary Fault Diagnosis Method for Rotating Rectifier of Multi-stage Generator

Abstract

The present invention relates to a method for diagnosing secondary faults of a rotating rectifier of a multi-stage starting generator. If a single diode open circuit fault occurs in the rotating rectifier when the multi-stage starting generator is in the power generation stage, the system can be derated and run "with the fault". However, a single diode open circuit will cause the three bridge arms of the rotating rectifier to no longer be balanced, thereby increasing the risk of secondary faults. The method proposed in the present invention performs secondary fault diagnosis of the rotating rectifier based on the maximum point distribution characteristics of the voltage waveform at the idle winding end of the stator of the exciter. The proposed method makes full use of the idle excitation winding of the exciter when the system is in the power generation stage. The algorithm is simple and can diagnose the secondary faults of the rotating rectifier online in real time.

Description

Technical Field

[0001] The invention belongs to the technical field of motor system fault diagnosis, and in particular relates to a secondary fault diagnosis method for a rotating rectifier of a multi-stage starter generator. Background Art

[0002] The vision of green aviation has put forward higher requirements for the development of more electric / all electric aircraft. Large capacity, high efficiency and high reliability of integrated starting / generating technology is one of the key technologies in the field of more electric / all electric aircraft. Multi-stage brushless synchronous motor has become one of the important research objects in this field due to its mature power generation technology and controllable excitation. Figure 1 As shown, the multi-stage generator is composed of coaxially mounted auxiliary exciter, exciter, rotating rectifier and main motor.

[0003] In the starting and generating stages of the multi-stage starter generator, the exciter provides DC excitation current to the main motor through the rotating rectifier. Therefore, the normal operation of the rotating rectifier is an important guarantee for the safe operation of the entire starting and generating system. However, since the rotating rectifier is located on the rotor side and operates under harsh conditions such as high-speed rotation, vibration, and high temperature for a long time, the failure rate of the rotating rectifier is much higher than that of other components. Therefore, in order to ensure the safe operation of the system, it is of great significance to perform fault diagnosis on the rotating rectifier. The rotating rectifier is a three-phase full-bridge rectifier circuit composed of 6 diodes. In practical applications, if a single diode open circuit fault occurs in the rotating rectifier when the multi-stage starter / generator is in the generating stage, the system can be derated and operated "with disease" by adjusting the excitation and other methods. However, since a single diode open circuit will cause the three bridge arms to no longer be balanced, the risk of the rotating rectifier failing again is increased. Therefore, the present invention is mainly aimed at the secondary fault diagnosis of the rotating rectifier of the multi-stage starter generator, including the distinction between open circuit and short circuit fault types and the positioning of the faulty diode under open circuit fault.

[0004] The present application is different from the prior art as follows:

[0005] Technical comparison with the public patent CN 118465529 A "A method for online diagnosis of secondary faults of rotating rectifiers of multi-stage starter generators";

[0006] Patent CN 118465529 A estimates the exciter rotor current by measuring the exciter stator voltage, current and rotor position, and then uses the estimated rotor current for fault diagnosis, while this patent directly uses the idle winding terminal voltage on the stator side of the exciter for fault diagnosis. There is an essential difference between the two in terms of technical thinking.

[0007] Patent CN 118465529 A diagnoses secondary faults of rotating rectifiers by using the average value characteristics of the estimated rotor three-phase current, while this patent diagnoses secondary faults by using the maximum value distribution characteristics of the idle winding terminal voltage on the stator side of the exciter. There is an essential difference between the two in terms of algorithm. Summary of the invention

[0008] With regard to the fault diagnosis of a rotating rectifier of a multi-stage starting generator, the present invention proposes a secondary fault diagnosis method for a rotating rectifier of a multi-stage starting generator. After an open-circuit fault occurs in a single diode of the rotating rectifier of the multi-stage starting generator and the generator is operated at a reduced rating with the fault, online diagnosis of the secondary fault of the rotating rectifier is achieved, including the distinction between open-circuit and short-circuit fault types and the location of the faulty diode under an open-circuit fault.

[0009] To achieve the above object, the technical solution adopted by the present invention is:

[0010] A secondary fault diagnosis method for a multi-stage generator rotating rectifier comprises the following steps:

[0011] Step 1: Online obtain the first characteristic voltage value of the idle winding terminal voltage of the exciter within one cycle, and calculate the second characteristic voltage value by voltage sequence recombination:

[0012] Step 2: Set the voltage sequence Further reconstruct into three new voltage sequences and calculate the maximum values ​​of these three voltage sequences respectively:

[0013] Step 3: Calculate the voltage ratio and obtain the fault characteristic value:

[0014] Step 4: Combine the characteristic voltage ratio R and the fault characteristic value Q to diagnose the secondary fault type of the rotating rectifier.

[0015] As a further improvement of the present invention, step 1 is specifically as follows:

[0016] 1.1 Based on the fundamental frequency calculated from the exciter speed, the voltage sensor is used to measure and collect the voltage at the idle winding end of the exciter within one cycle using a sliding window method. , forming a voltage sequence , where N is the number of sampling points in one cycle;

[0017] 1.2 Calculate the maximum value of the idle winding terminal voltage within a cycle , recorded as the first characteristic voltage value, and recorded The position in the voltage series is denoted as M;

[0018] 1.3 Divide the idle winding terminal voltage sequence in one cycle into two groups, denoted as and ,sequence The number of data is , The number of data is , for The rounded integer is based on the number of data in the sequence and At position M in sequence U, then:

[0019] ;

[0020] like ,but ;like ,but ;in ;

[0021] 1.4 Calculation of voltage series The maximum value is recorded as the second characteristic voltage value .

[0022] As a further improvement of the present invention, step 2 is specifically as follows:

[0023] 2.1 Further reconstructed into three new voltage sequences, denoted as , and ,sequence and The number of data is , The number of data is , for The integer after rounding;

[0024] 2.2 According to the number of data in the sequence, then;

[0025] ;

[0026] like ,but ;like ,but ;in ;

[0027] 2.3 Calculate the sequence separately , and The maximum value of , and .

[0028] As a further improvement of the present invention, step 3 is specifically as follows:

[0029] 3.1 Define the ratio of the first characteristic voltage value to the second characteristic voltage value as the characteristic voltage ratio R, and use the formula Calculate and obtain; define the first characteristic voltage value and , , The ratios are the voltage ratios R1, R2 and R3, and are respectively calculated by the formula , and Calculate acquisition;

[0030] 3.2 Define the fault characteristic value Q, whose value is the value of R1, R2 and R3 within the set threshold range By comparing the values ​​of R1, R2 and R3 with the set threshold range Compare and obtain Q.

[0031] As a further improvement of the present invention, step 4 is specifically as follows:

[0032] 4.1 Comparison of R value with set threshold and :like This indicates that the secondary fault of the rotating rectifier is an open circuit fault of another diode in the same bridge arm as the faulty diode; if This indicates that the secondary fault of the rotating rectifier is a short-circuit fault;

[0033] 4.2 If , further combined with the fault characteristic quantity Q for diagnosis: if Q=1, it indicates that another diode in a different bridge arm and on the same side as the faulty diode has an open circuit fault; if Q=2, it indicates that a diode in a different bridge arm and on the opposite side as the faulty diode has an open circuit fault; if Q=3, it indicates that no secondary fault has occurred in the rotating rectifier;

[0034] Said The value of is 0.9~1.2, which is determined according to the actual application object;

[0035] Said The value is 7.0~8.0, which is determined according to the actual application object.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] The present invention proposes a method for secondary fault diagnosis of rotating rectifier of multi-stage starting generator by using the terminal voltage of idle winding of exciter in power generation state. The method has the following advantages: 1) secondary fault diagnosis of rotating rectifier in "defective" operation state (single diode open circuit fault has occurred) can be realized, including fault type judgment and diode location under open circuit fault; 2) idle excitation winding of exciter is fully utilized when the system is in power generation state; 3) data processing process and algorithm are concise and easy to realize online operation. The proposed method is helpful to improve the reliability of multi-stage starting system and avoid fault propagation. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 : Schematic diagram of the multi-stage generator structure;

[0039] Figure 2 : Block diagram of the secondary fault diagnosis method for a rotating rectifier according to the present invention;

[0040] Figure 3 : Schematic diagram of equivalent circuit of rotor part of multi-stage generator;

[0041] Figure 4 : The first characteristic voltage value and the second characteristic voltage value of the idle winding terminal voltage of the exciter;

[0042] Figure 5 : Schematic diagram of idle winding terminal voltage and terminal voltage grouping when D3 is open circuit fault;

[0043] Figure 6 : Recombination voltage sequence , and The maximum value of

[0044] Figure 7 : Characteristic voltage ratio of the idle winding terminal voltage of the exciter. DETAILED DESCRIPTION

[0045] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments:

[0046] The present invention is further described in conjunction with the embodiments and drawings, and the present invention includes but is not limited to the following embodiments. In this embodiment, the exciter of the multi-stage generator is a three-phase excitation winding structure, and the motor running speed is 10000r / min. Figure 2 The figure shows a block diagram of the secondary fault diagnosis method of the rotating rectifier proposed in the present invention. Figure 3 As a premise, an open circuit fault occurs in the diode D3 (or D5), and an open circuit fault occurs in the diode D3 (or D5) as an example to illustrate the proposed fault diagnosis method. The specific steps included in the embodiment are as follows:

[0047] Step 1: Online obtain the first characteristic voltage value of the idle winding terminal voltage of the exciter within one cycle, and calculate the second characteristic voltage value by voltage sequence recombination, as follows:

[0048] 1.1 The fundamental frequency calculated based on the exciter speed of 10000r / min is 500Hz, and the sampling frequency is 100kHz. Then the number of sampling points N of the idle winding terminal voltage of the exciter in one cycle is 200. The voltage sensor is used to measure and collect the idle winding terminal voltage of the exciter in one cycle in a sliding window manner. , forming a voltage sequence .

[0049] 1.2 Calculate the maximum value of the idle winding terminal voltage within a cycle, which is the first characteristic voltage value. ,like Figure 4 As shown. Simultaneous recording Position M in the voltage sequence, where M=130.

[0050] 1.3 Divide the idle winding terminal voltage sequence in one cycle into two groups, denoted as and , where the sequence and The number of data is 100. Figure 5 As shown, according to the number of sequence data and At position M in sequence U, then

[0051] ;

[0052] 1.4 Calculate and obtain voltage sequence The maximum value is the second characteristic voltage value ,like Figure 4 shown.

[0053] Step 2: Set the voltage sequence Further reconstruct into three new voltage sequences and calculate the maximum values ​​of these three voltage sequences respectively, as follows:

[0054] 2.1 Further reconstructed into three new voltage sequences, denoted as , and ,sequence The number of data is 33. The number of data is 33. The number of data is 34, such as Figure 5 shown.

[0055] 2.2 According to the number of data in the sequence, then;

[0056] ;

[0057] 2.3 As Figure 6 As shown, , and The maximum value of , , ;

[0058] Step 3: Calculate the voltage ratio and fault characteristic value in real time, as follows:

[0059] 3.1 Calculation of characteristic voltage ratio ,like Figure 7 As shown. At the same time, the voltage ratio is calculated , and , between The number of intervals is 1, so Q=1.

[0060] Step 4: Combine the voltage ratio and fault characteristic value Q to determine and locate the secondary fault type of the rotating rectifier, as follows:

[0061] 4.1 Combined with the secondary fault diagnosis criteria in Table 1, due to exist The value is within the range and Q=1, indicating that the secondary fault is an open circuit fault of diode D3 (or D5).

[0062] Table 1

[0063] ;

[0064] The above description is only a preferred embodiment of the present invention and does not constitute any other form of limitation to the present invention. Any modification or equivalent change made based on the technical essence of the present invention still falls within the scope of protection required by the present invention.

Claims

1. A secondary fault diagnosis method for a multi-stage generator rotating rectifier, characterized in that: The steps include: Step 1: online obtaining a first characteristic voltage value of the idle winding terminal voltage of the exciter within one cycle, and calculating a second characteristic voltage value by voltage sequence recombination; Step 1 is as follows: 1.1 Based on the fundamental frequency calculated from the exciter speed, the voltage sensor is used to measure and collect the voltage at the idle winding end of the exciter within one cycle using a sliding window method. , forming a voltage sequence , where N is the number of sampling points in one cycle; 1.2 Calculate the maximum value of the idle winding terminal voltage within a cycle , recorded as the first characteristic voltage value, and recorded The position in the voltage series is denoted as M; 1.3 Divide the idle winding terminal voltage sequence in one cycle into two groups, denoted as and ,sequence The number of data is , The number of data is , for The rounded integer is based on the number of data in the sequence and At position M in sequence U, then: ； like ,but ;like ,but ;in ; 1.4 Calculation of voltage series The maximum value is recorded as the second characteristic voltage value ; Step 2: Set the voltage sequence Further reconstruct into three new voltage sequences and calculate the maximum values ​​of the three voltage sequences respectively; Step 2 is as follows: 2.1 Further reconstructed into three new voltage sequences, denoted as , and ,sequence and The number of data is , The number of data is , for The integer after rounding; 2.2 According to the number of data in the sequence, then; ； like ,but ;like ,but ;in ; 2.3 Calculate the sequence separately , and The maximum value of , and ; Step 3: Calculate the voltage ratio and obtain the fault characteristic value; Step 3 is as follows: 3.1 Define the ratio of the first characteristic voltage value to the second characteristic voltage value as the characteristic voltage ratio R, and use the formula Calculate and obtain; define the first characteristic voltage value and , , The ratios are the voltage ratios R1, R2 and R3, and are respectively calculated by the formula , and Calculate acquisition; 3.2 Define the fault characteristic value Q, whose value is the value of R1, R2 and R3 within the set threshold range By comparing the values ​​of R1, R2 and R3 with the set threshold range Compare and obtain Q; Step 4: diagnose the secondary fault type of the rotating rectifier by combining the characteristic voltage ratio R and the fault characteristic value Q; Step 4 is as follows: 4.1 Comparison of R value with set threshold and :like This indicates that the secondary fault of the rotating rectifier is an open circuit fault of another diode in the same bridge arm as the faulty diode; if This indicates that the secondary fault of the rotating rectifier is a short-circuit fault; 4.2 If , further combined with the fault characteristic quantity Q for diagnosis: if Q=1, it indicates that another diode in a different bridge arm and on the same side as the faulty diode has an open circuit fault; if Q=2, it indicates that a diode in a different bridge arm and on the opposite side as the faulty diode has an open circuit fault; if Q=3, it indicates that no secondary fault has occurred in the rotating rectifier; Said The value of is 0.9~1.2, which is determined according to the actual application object; Said The value is 7.0~8.0, which is determined according to the actual application object.

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