Aviation multi-pulse transformer rectifier single diode open-circuit fault diagnosis and positioning method

Abstract

The invention relates to a single diode open-circuit fault diagnosis and positioning method for an aviation multi-pulse transformer rectifier, which can effectively solve the problem that the early-stage single diode open-circuit fault detection methods of rectifier bridges in different types of aviation multi-pulse transformer rectifiers are not unified. Acquiring a direct-current component in primary / secondary side current of the phase-shifting transformer by using a low-pass filter, defining a direct-current component residual error of the primary side current, and judging whether a single diode open-circuit fault occurs in a rectifier bridge in the aviation multi-pulse transformer rectifier or not; if a fault occurs, comparing absolute values of direct-current components of any two phases of primary side current, and simultaneously obtaining a maximum value of absolute values of direct-current components of secondary side current so as to judge a rectifier bridge where the fault diode is located and a phase where the fault diode is located; furthermore, whether an upper bridge arm diode or a lower bridge arm diode is in an open circuit state is judged by calculating the difference between the absolute value of the maximum value and the absolute value of the minimum value of the secondary side current in one period, and finally the functions of diagnosis and positioning of the open-circuit fault of the single diode of the rectifier bridge in the aviation multi-pulse transformer rectifier can be achieved. The diagnosis and positioning method is high in universality, simple and easy to implement, the direct-current component of each current can be obtained only through the low-pass filter, early faults can be found, and safe operation of the aviation secondary power supply system can be maintained.

Description

Technical Field

[0001] This invention belongs to the field of fault diagnosis technology for aviation secondary power supply systems, specifically relating to a method for diagnosing and locating an open-circuit fault in a single diode of a rectifier bridge in an aviation multi-pulse transformer rectifier. It is a method for diagnosing and locating the faulty diode by analyzing the DC component of the primary / secondary current of the phase-shifting transformer. Background Technology

[0002] More than 30% of the onboard equipment in modern aircraft relies on DC power. Multi-pulse transformer rectifiers are typical components for converting AC to DC power in aircraft. They generally include 12-pulse, 18-pulse, or 24-pulse types, employing phase-shifting transformers with different connections to cancel specific harmonics on the AC grid side and reduce DC output voltage ripple. Typical multi-pulse transformer rectifier parallel or series structures are shown below. Figure 1 As shown, using The structure of three-phase uncontrolled rectifier bridges connected in parallel or series can achieve load "splitting" or "voltage division".

[0003] Under the influence of strong vibration, high stress, and wide temperature range in the aviation environment, the rectifier bridge of multi-pulse transformer rectifiers is prone to single diode open-circuit or short-circuit faults, accounting for more than 60% of all fault types. Short-circuit faults can cause overcurrents tens or even hundreds of times greater than normal currents, and are easily detected and isolated. After an open-circuit fault, the multi-pulse transformer rectifier can still operate for a short period, with no obvious voltage / current changes, especially under light loads, where the fault characteristics are masked, making early detection difficult. In this situation, the remaining diodes will bear greater electrical stress, exacerbating the fault risk and even leading to system-level failure. Therefore, early open-circuit diagnosis of diodes in aviation transformer rectifiers, i.e., single diode open-circuit fault diagnosis, is of significant practical importance for improving the reliability of multi-pulse transformer rectifiers and reducing component replacement costs.

[0004] Currently, intelligent diagnosis of open-circuit faults in diodes of multi-pulse transformer rectifiers mainly relies on analyzing the time / frequency domain changes of the output voltage before and after the fault, or on "black box" analysis using intelligent algorithms. These methods require certain expert knowledge, are closely related to the working principle of multi-pulse transformer rectifiers, and require a large amount of historical fault data. They also lack universality and place high demands on the engineering skills of personnel. Therefore, this patent proposes a universal method for diagnosing single open-circuit faults in aerospace transformer rectifiers, which has advantages such as strong universality, simple implementation, strong theoretical interpretability, and wide applicability. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a method for diagnosing and locating open-circuit faults in a single diode of an aviation multi-pulse transformer rectifier.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] This invention provides a method for diagnosing and locating open-circuit faults in a single diode of an aviation multi-pulse transformer rectifier, comprising the following steps:

[0008] Step 1: Determine the turns ratio N and pulse number of the multi-pulse transformer rectifier. Input voltage fundamental frequency Parameters;

[0009] Determine the primary / secondary winding connection method of the phase-shifting transformer in the multi-pulse transformer rectifier. The connection methods include star connection and delta connection. Mark the star-connected windings sequentially. ,in ; Delta connection winding marking .

[0010] Step 2: Collect the three-phase current on the primary side of the phase-shifting transformer, and record it as... The primary three-phase current is obtained using a low-pass filter. The DC component in the equation is denoted as... .

[0011] Step 3: Calculate the residuals of any two-phase DC components.

[0012] ;

[0013] ;

[0014] .

[0015] Step 4: According to , , Determining if an open-circuit fault occurs in the rectifier diodes of a multi-pulse transformer rectifier:

[0016] If the residual satisfies If the condition is met, all rectifier bridges in the multi-pulse transformer rectifier are in a healthy state; otherwise, an open-circuit fault occurs in one of the rectifier diodes. It is a near-zero preset value.

[0017] Step 5: According to and , , Determine the location of the diode with an open-circuit fault in the rectifier bridge:

[0018] If satisfied and If the faulty diode that is open-circuited is located in the rectifier bridge connected to the secondary winding of the phase-shifting transformer in a star configuration;

[0019] If satisfied and If the diode that has an open-circuit fault is located in the rectifier bridge connected to the secondary winding of the phase-shifting transformer in a delta connection, then the diode that has an open-circuit fault is located in the rectifier bridge.

[0020] Furthermore, depending on the requirements, the method for diagnosing and locating open-circuit faults in a single diode of an aviation multi-pulse transformer rectifier also includes the following steps:

[0021] Step 6: Determine the position of the diode with the open-circuit fault in the rectifier bridge phase:

[0022] If an open-circuit fault occurs, the diode is located in the rectifier bridge connected to the secondary winding of the phase-shifting transformer in a star configuration. The corresponding data are collected. The three-phase input current of the rectifier bridge Low-pass filtering yields DC component sequence The maximum absolute value of the DC component The phase of the bridge in question is the location of the diode that experienced the open-circuit fault.

[0023] If the diode experiencing an open-circuit fault is located in the rectifier bridge connected to the secondary winding of the phase-shifting transformer in a delta configuration, the corresponding data should be collected. The three-phase input current of the rectifier bridge Low-pass filtering yields DC component sequence The maximum absolute value of the DC component The phase of the bridge in question is the location of the diode that experienced the open-circuit fault.

[0024] Step 7: At a certain time k, calculate the current in the phase where the open-circuit fault diode is located. or The difference between the absolute values ​​of the maximum and minimum values ​​within a period. or .

[0025] Step 8: Determine whether the open-circuit faulty diode is located in the upper or lower arm of the rectifier bridge:

[0026] If satisfied or If an open-circuit fault occurs, the diode is located in the lower bridge arm; if the following conditions are met... or If an open-circuit fault occurs, the diode is located in the upper bridge arm, where... It is a near-zero preset value.

[0027] The above criteria are summarized in the table below:

[0028]

[0029] Further, in step 4, the... The value range is 1% to 5% of the primary input current of the phase-shifting transformer.

[0030] Furthermore, in step 8, the... The value range is 1% to 5% of the amplitude of the secondary output current of the phase-shifting transformer.

[0031] This invention proposes a method for diagnosing and locating open-circuit faults in single diodes of multi-pulse transformer rectifiers for aircraft. By analyzing the impact of open-circuit faults on the DC components of the primary / secondary currents of the phase-shifting transformer in the multi-pulse transformer rectifier, a DC component residual is constructed to determine whether a fault has occurred in the multi-pulse transformer rectifier. If a fault occurs, the phase of the bridge containing the faulty diode is determined by comparing the DC components of the currents in each phase. Furthermore, the sum of the maximum and minimum values ​​of the faulty phase current within one cycle is used to determine whether the faulty diode is located in the upper or lower bridge arm, thus achieving fault diagnosis and precise location. Attached Figure Description

[0032] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below.

[0033] Figure 1 Schematic diagram of parallel / series structure of multi-pulse transformer rectifier;

[0034] Figure 2 This is a schematic diagram of a typical 12-pulse transformer rectifier series structure;

[0035] Figure 3 Waveforms of primary / secondary voltage / current of the phase-shifting transformer in a 12-pulse transformer-rectifier when it is in a healthy state;

[0036] Figure 4 Block diagram of a method for diagnosing and locating open circuits in a single diode of an aviation multi-pulse transformer rectifier;

[0037] Figure 5 Waveforms of primary / secondary voltage / current of the phase-shifting transformer in a 12-pulse transformer rectifier when D11 is open-circuited;

[0038] Figure 6 The residual DC component of the primary current of the phase-shifting transformer during the open circuit period of D11 in rectifier bridge 1 from the healthy state;

[0039] Figure 7 The absolute value of the DC component of the primary current of the phase-shifting transformer during the open circuit period of D11 in rectifier bridge 1 from the healthy state;

[0040] Figure 8The absolute value of the DC component of the secondary current of the phase-shifting transformer connected in star configuration during the open circuit period from the health point to D11 in rectifier bridge 1;

[0041] Figure 9 The waveform represents the fault phase current, maximum / minimum current, and the difference between the absolute values ​​of maximum / minimum current during the period from the healthy state to the open circuit of D11 in rectifier bridge 1. Detailed Implementation

[0042] The exemplary embodiments of this application are described below with reference to the accompanying drawings, including various details of the embodiments to aid understanding, and should be considered merely exemplary. Those skilled in the art will recognize that modifications can be made to the embodiments described herein without departing from the scope and spirit of this application. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.

[0043] Aviation multi-pulse transformer rectifiers can be classified into two types according to their connection method with the load: parallel and series. Figure 1 As shown. When connected in parallel, each rectifier bridge shares the load current equally, achieving "current sharing operation," which allows for flexible capacity expansion and is suitable for modular development; when connected in series, the sum of the output voltages of each rectifier bridge is the voltage across the load, achieving "voltage sharing operation," which is suitable for high-voltage DC output, effectively avoiding insufficient voltage withstand capability of a single device, and improving device reliability.

[0044] like Figure 2 The typical 12-pulse transformer rectifier series structure shown corresponds to j Current , , The phase-shifting transformer is connected via a star-connected winding. The secondary winding of the phase-shifting transformer uses a Yy0d11 connection, meaning the secondary winding of the phase-shifting transformer connected to rectifier bridge 1 uses a star connection with the same phase, while the secondary winding of the phase-shifting transformer connected to rectifier bridge 2 uses a delta connection with a 30° lead. The two sets of secondary currents are respectively... , , and , , The rectifier bridge supplies current to the load. Assume the input voltage of phase a is expressed as... The initial phase is , effective value , , The voltages of phases b and c lag behind and lead phase a by 120°, respectively.

[0045] Under healthy conditions, the primary / secondary voltage / current waveforms of the phase-shifting transformer are as follows: Figure 3 As shown, the load current In a star-connected configuration, the secondary current is in phase with the primary current. In a delta connection, the secondary current leads the primary current by 30°. DC component of primary current in phase-shifting transformer Both are close to 0, and the residuals of any two phases are expressed as:

[0046]

[0047] This indicates that all rectifier bridges in the multi-pulse transformer rectifier are in good condition.

[0048] Figure 4 The diagram illustrates the method for diagnosing and locating open circuits in a single diode of an aerospace multi-pulse transformer rectifier according to the present invention, using a diode... Taking an open-circuit fault as an example, the voltage / current waveforms of the primary / secondary sides of the phase-shifting transformer are as follows: Figure 5 As shown, compared to the healthy state, the primary current... The waveform phase remains unchanged, but the amplitude exhibits varying degrees of distortion. Ignoring switching losses and magnetic saturation effects, the theoretical value of the DC component of the primary current is derived as follows:

[0049]

[0050] Where N is the phase-shifting transformer turns ratio. Multi-pulse transformer rectifier from healthy to... The residual waveforms of the DC components of the primary currents of any two phases of the phase-shifting transformer during the open-circuit period, such as... Figure 6 As shown, it satisfies

[0051]

[0052] This indicates that an open-circuit fault has occurred in a diode within the multi-pulse transformer rectifier. Simultaneously, the waveform of the absolute value of the DC component of the primary current in the phase-shifting transformer is as follows: Figure 7 As shown, the absolute value of the DC component of the primary current in phase a is approximately twice that of phases b and c, satisfying... Therefore, the diode that experiences an open-circuit fault in the multi-pulse transformer rectifier is located in rectifier bridge 1, which is connected to the secondary winding of the phase-shifting transformer in a star configuration.

[0053] At this time, the input voltage / current waveform of rectifier bridge 1, which is connected to the secondary winding of the phase-shifting transformer in a star configuration, is as follows: Figure 5 As shown. Input current The waveform amplitude remains basically unchanged. Only the negative half-axis waveform is present. and The conduction range of the positive half-axis waveform increases. The input current of rectifier bridge 2... , , The waveform remains unchanged. Ignoring switching losses and magnetic saturation effects, the theoretical value of the DC component of the input current of rectifier bridge 1 is derived as follows:

[0054]

[0055] Therefore, the absolute value waveform of the DC component of the secondary current of the phase-shifting transformer during the period from health to D11 open circuit is obtained as follows: Figure 8 As shown, the maximum absolute value is The diode that caused the open-circuit fault is located in phase a1 of rectifier bridge 1.

[0056] Furthermore, the phase current of rectifier bridge 1 (a1 phase) is obtained from the period from the healthy state to the open circuit of D11. Its maximum and minimum values ​​are calculated for each cycle, and the difference between the absolute values ​​of the corresponding maximum and minimum values ​​is calculated. The waveform is shown below. Figure 9 As shown. When diode D11 is open, The diode that caused the open-circuit fault is located in the upper bridge arm.

[0057] Based on the above analysis, it was finally determined that the upper bridge arm diode of phase a1 in rectifier bridge 1, which is connected to the secondary winding of the phase-shifting transformer in a star configuration, had an open-circuit fault, consistent with the assumptions in the embodiment.

[0058] It should be noted that this method is also applicable to embodiments with inductive / capacitive loads under different operating conditions. Furthermore, the present invention has different variations in other structural aero-engine transformer rectifiers, all of which remain within the scope of the present invention.

[0059] The specific embodiments described above do not constitute a limitation on the scope of protection of this application. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for diagnosing and locating open-circuit faults in a single diode of an aviation multi-pulse transformer rectifier, characterized in that... The steps are as follows: Step 1: Determine the turns ratio N and pulse number of the aircraft multi-pulse transformer rectifier. Input voltage fundamental frequency Parameters; Determine the connection method of the primary / secondary windings of the phase-shifting transformer in the aviation multi-pulse transformer rectifier. The connection methods include star connection and delta connection. Mark the star-connected windings sequentially. ,in ; Delta connection winding marking ; Step 2: Collect the three-phase current on the primary side of the phase-shifting transformer, and record it as... The primary three-phase current is obtained using a low-pass filter. The DC component in the equation is denoted as... ; Step 3: Calculate the residuals of any two-phase DC components. ， ， ； Step 4: According to , , Determining if an open-circuit fault occurs in the rectifier diodes of an aviation multi-pulse transformer rectifier: If the residual satisfies If all rectifier bridges in the multi-pulse transformer rectifier are in good condition, then all rectifier bridges in the multi-pulse transformer rectifier are in good condition; otherwise, some rectifier diodes in the multi-pulse transformer rectifier have an open-circuit fault. It is a near-zero preset value; Step 5: According to and , , Determine the location of the diode with an open-circuit fault in the rectifier bridge: If satisfied and If the diode that has an open-circuit fault is located in the rectifier bridge connected to the secondary winding of the phase-shifting transformer in a star configuration, then the diode that has an open-circuit fault is located in the rectifier bridge. If satisfied and If the diode that has an open-circuit fault is located in the rectifier bridge connected to the secondary winding of the phase-shifting transformer in a delta connection, then the diode that has an open-circuit fault is located in the rectifier bridge.

2. The method for diagnosing and locating open-circuit faults in a single diode of an aviation multi-pulse transformer rectifier according to claim 1, characterized in that, Also includes: Step 6: Determine the position of the diode with the open-circuit fault in the rectifier bridge phase: If the open-circuit diode is located in the rectifier bridge connected to the secondary winding of the phase-shifting transformer in a star configuration, the corresponding data will be collected. The three-phase input current of the rectifier bridge Low-pass filtering yields DC component sequence The maximum absolute value of the DC component The phase of the bridge in which the open-circuit fault occurs is the location of the diode. If the open-circuit diode is located in the rectifier bridge connected to the secondary winding of the phase-shifting transformer in a delta configuration, the corresponding data will be collected. The three-phase input current of the rectifier bridge Low-pass filtering yields DC component sequence The maximum absolute value of the DC component The phase of the bridge in which the open-circuit fault occurs is the location of the diode. Step 7: At a certain time k, calculate the current in the phase containing the faulty diode. or The difference between the absolute values ​​of the maximum and minimum values ​​within a period. or ; Step 8: Determine whether the open-circuit faulty diode is located in the upper or lower arm of the rectifier bridge: If satisfied or If an open-circuit fault occurs, the diode is located in the lower arm of the rectifier bridge. If satisfied or If the open-circuit fault occurs, the diode is located in the upper arm of the rectifier bridge, where... It is a near-zero preset value.

3. The method for diagnosing and locating open-circuit faults in a single diode of an aviation multi-pulse transformer rectifier according to claim 1, characterized in that, In step 4 The value range is 1% to 5% of the primary input current of the phase-shifting transformer.

4. The method for diagnosing and locating open-circuit faults in a single diode of an aviation multi-pulse transformer rectifier according to claim 1, characterized in that, In step 8, the The value range is 1% to 5% of the amplitude of the secondary output current of the phase-shifting transformer.

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