A Fault Diagnosis Method for H-Bridge Half-Controlled Rectifier of an Electrically Excited Doubly Salient Generator

Abstract

The present application discloses a fault diagnosis method for an H-bridge half-controlled rectifier of an electrically excited double-pole generator, which relates to the field of electrically excited double-pole generators. The method is based on an improved H-bridge half-controlled rectifier topology structure. The improved H-bridge half-controlled rectifier topology structure adds a current sensor to each phase armature winding, and the wires of the left and right bridge arms connected to each phase armature winding are wound around the current sensor by winding, so that each phase current sensor can obtain more current information. The current measured by the current sensor wound by the working two-phase armature winding in each sector can realize open circuit fault diagnosis. The method has a small amount of calculation and is easy to implement. It is not affected by changes in speed or load, nor is it affected by changes in the fault location and conduction angle. It can realize single-tube, double-tube and multi-tube fault positioning, has good diagnostic effect and a wide range of applications.

Description

Technical Field

[0001] The present application relates to the field of electrically excited doubly salient generators, and in particular to a fault diagnosis method for an H-bridge half-controlled rectifier of an electrically excited doubly salient generator. Background Art

[0002] The doubly salient electromagnetic generator (DSEG) boasts a simple structure, high reliability, and strong adaptability to high-temperature, high-speed operating environments. It also offers significant advantages in voltage regulation and fault demagnetization, and holds broad application prospects in fields such as aviation and wind power. Compared to traditional uncontrolled rectifier systems, the DSEG controlled rectifier system, based on an H-bridge semi-controlled rectifier (HBSCR), regulates armature current by varying the conduction angle of the switching tube. Because its three-phase currents are uncoupled, commutation overlap is minimized, significantly increasing motor output power, reducing losses, and optimizing motor performance. Consequently, this technology has attracted widespread attention.

[0003] However, due to its harsh operating environment, the HBSCR is the weakest link in the entire power generation system, often exhibiting short-circuit and open-circuit faults. Open-circuit faults can degrade DC voltage quality, reduce system load capacity, and reduce power generation. Short-circuit faults can cause severe overcurrent in the phase windings, severely damaging the system. Short-circuit faults are characterized by fast response and high damage, necessitating a rapid response to short-circuit faults. Currently, conventional methods convert short-circuit faults into open-circuit faults through hardware circuitry. Therefore, to improve the reliability of DSEG systems, research on diagnostic methods for open-circuit faults in HBSCR switches is crucial. Summary of the Invention

[0004] In response to the above problems and technical needs, this application proposes a fault diagnosis method for an H-bridge half-controlled rectifier of an electrically excited doubly salient generator. The technical solution of this application is as follows:

[0005] A fault diagnosis method for an H-bridge half-controlled rectifier of an electrically excited doubly salient generator is disclosed. The method comprises: a lower bridge arm conductor of a left bridge arm connected to any M-phase armature winding in the electrically excited doubly salient generator passes through an M-phase current sensor CSM from a P-pole to a N-pole and is wound one turn; an upper bridge arm conductor of a left bridge arm connected to the M-phase armature winding passes through the M-phase current sensor CSM from a N-pole to a P-pole and is wound two turns; an upper bridge arm conductor of a right bridge arm connected to the M-phase armature winding passes through the M-phase current sensor CSM from a P-pole to a N-pole and is wound two turns; and a lower bridge arm conductor of a right bridge arm connected to the M-phase armature winding passes through the M-phase current sensor CSM from a N-pole to a P-pole and is wound one turn; M=A, B, C respectively represent the three-phase armature windings in the electrically excited doubly salient generator; and the current positive direction is from the midpoint of the right bridge arm connected to any M-phase armature winding to the midpoint of the left bridge arm.

[0006] The fault diagnosis method of the H-bridge half-controlled rectifier of the electrically excited doubly salient generator includes:

[0007] Get the current i of the current sensor wound by the bridge arm connected to the forward working winding Z in the sector where the rotor position angle θ is currently located CSZ , and the current i of the current sensor wound by the bridge arm connected to the negative working winding Q in the current sector CSQ ; The positive working winding Z and the negative working winding Q are two-phase armature windings in the electrically excited doubly salient generator;

[0008] The lower bridge arm switch tube T in the left bridge arm connected to the forward working winding Z Z1 The lower bridge arm switch tube T of the right bridge arm connected to the negative working winding Q Q2 During the conduction process, when the current i CSZ In case of abnormality, determine the lower bridge arm switch tube T in the left bridge arm connected to the forward working winding Z. Z1 An open circuit fault occurs. When the current i CSQ In case of abnormality, determine the lower bridge arm switch tube T in the right bridge arm connected to the negative working winding Q Q2 An open circuit fault has occurred.

[0009] The beneficial technical effects of this application are:

[0010] This application discloses a fault diagnosis method for an H-bridge half-controlled rectifier in an electrically excited doubly salient generator. The method is based on an improved H-bridge half-controlled rectifier topology. The improved H-bridge half-controlled rectifier topology adds a current sensor to each armature winding phase. The wires connecting the left and right bridge arms of each armature winding phase are wound around the current sensor, allowing each phase current sensor to obtain more current information. Within each sector, the current provided by the current sensors wound around the two working armature windings enables open-circuit fault diagnosis. This method requires little computation and is easy to implement. Furthermore, the method is unaffected by speed or load variations, fault location, or conduction angle variations, broadening the applicability of the diagnostic method and demonstrating strong robustness. This method can locate single-, dual-, and multi-tube faults and can be extended to diagnose open-circuit faults in switch tubes in N-phase DSEG controlled rectifier systems, encompassing a wide range of diagnostic applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is the topology of the traditional HBSCR-based electrically excited doubly salient generator controlled rectifier system.

[0012] Figure 2 This is the topology of the HBSCR-based electrically excited doubly salient-pole generator controllable rectifier system of the present application.

[0013] Figure 3 It is a control strategy diagram of the HBSCR-based electrically excited doubly salient generator controlled rectifier system in one electrical angle cycle.

[0014] Figure 4 It is the current loop of the A-phase armature winding in the forward energy storage and current increasing stage in sector 1.

[0015] Figure 5 It is the current loop of the A-phase armature winding in the forward freewheeling power generation stage in sector 1.

[0016] Figure 6 In sector 1, when the armature winding of phase A is connected to the lower bridge arm switch tube T of the left bridge arm A1 Waveform of phase A current during normal operation.

[0017] Figure 7 This is the system current flow diagram before 0° commutation.

[0018] Figure 8 It is the current loop of the C-phase winding formed in sector 1 when the positive C-phase current has continued to flow to 0 at 0°.

[0019] Figure 9 It is the current loop of the C-phase winding formed in sector 1 when there is a positive C-phase current at 0°.

[0020] Figure 10 In sector 1, [0°,θ c ] interval, the lower bridge arm switch tube T A1 The waveform diagram during normal operation and the lower bridge arm switch tube T A1 Current loop and waveform diagram when an open circuit fault occurs.

[0021] Figure 11 It is the current loop of the C-phase armature winding in the negative freewheeling power generation stage in sector 1.

[0022] Figure 12 In sector 1, when the armature winding of phase C is connected to the lower bridge arm switch tube T of the right bridge arm C2 Waveform of phase C current during normal operation.

[0023] Figure 13 When the end point θ1 of the forward current commutation of phase C in sector 1 is at 0°, the lower arm switch tube T C2 The waveform diagram during normal operation and the lower bridge arm switch tube T C2 Current loop and waveform diagram when an open circuit fault occurs.

[0024] Figure 14 When the forward current commutation end point of phase C in sector 1 is 0°<θ1<θ c In the case of the lower bridge arm switch tube T C2 The waveform diagram during normal operation and the lower bridge arm switch tube T C2 Current loop and waveform diagram when an open circuit fault occurs.

[0025] Figure 15 When the forward current commutation of phase C in sector 1 ends, θ1>θ c In the case of the lower bridge arm switch tube T C2 Waveform diagram during normal operation.

[0026] Figure 16 The figure is a flow chart of a method for diagnosing a fault of an H-bridge half-controlled rectifier of an electrically excited doubly salient generator in an embodiment. DETAILED DESCRIPTION

[0027] The specific implementation of this application will be further described below with reference to the accompanying drawings.

[0028] The topology of the conventional H-bridge half-controlled rectifier HBSCR-based electrically excited doubly salient generator controlled rectifier system is as follows: Figure 1As shown, the electrically excited doubly salient generator includes three-phase armature windings, which are respectively denoted as A, B, and C phases. One end of any M-phase armature winding is connected to the midpoint of the bridge arm on its left side, and the other end is connected to the midpoint of the bridge arm on its right side. M = A, B, C represent the three-phase armature windings in the electrically excited doubly salient generator, respectively. m Represents the phase current of the M-phase armature winding, m = a, b, c corresponds to the case where the M-phase armature winding is A, B, C phase armature winding respectively, and the current is in the positive direction from the midpoint of the right bridge arm connected to any M-phase armature winding to the midpoint of the left bridge arm. The structure of each bridge arm is the same. A bridge arm includes an upper bridge arm diode and a lower bridge arm switch tube. The two ends of the lower arm switch tube are also connected in anti-parallel with diodes. The anode of the upper bridge arm diode is connected to the collector of the lower arm switch tube and serves as the midpoint of the bridge arm for connecting the armature winding. The cathode of the upper bridge arm diode is connected to the output positive electrode, and the emitter of the lower arm switch tube is connected to the output negative electrode. The load R is connected between the output positive electrode and the output negative electrode to provide the output voltage u. o , a filter capacitor C is also connected between the output positive electrode and the output negative electrode. For the sake of convenience, this application will record the upper bridge arm diode in the left bridge arm connected to any M-phase armature winding as D M1 , the lower bridge arm switch is marked as T M1 , lower bridge arm switch tube T M1 The anti-parallel diode is denoted as D M2 The upper bridge arm diode in the right bridge arm connected to the M-phase armature winding is denoted as D M3 , the lower bridge arm switch is marked as T M2 , lower bridge arm switch tube T M2 The anti-parallel diode is denoted as D M4 .

[0029] This application optimizes this traditional topology, and the optimized topology is as follows: Figure 2 As shown, the topology used in this application adds a phase current sensor to each of the three-phase armature windings. The current sensor added to any M-phase armature winding is denoted as CSM. The lower bridge arm wire of the left bridge arm connected to any M-phase armature winding passes through the M-phase current sensor CSM from the P pole to the N pole and is wound one turn. The upper bridge arm wire of the left bridge arm connected to the M-phase armature winding passes through the M-phase current sensor CSM from the N pole to the P pole and is wound two turns. The upper bridge arm wire of the right bridge arm connected to the M-phase armature winding passes through the M-phase current sensor CSM from the P pole to the N pole and is wound two turns. The lower bridge arm wire of the right bridge arm connected to the M-phase armature winding passes through the M-phase current sensor CSM from the N pole to the P pole and is wound one turn. The upper bridge arm wire of each bridge arm refers to the wire between the midpoint of the bridge arm and the upper bridge arm switch tube, and the lower bridge arm wire of each bridge arm refers to the wire between the midpoint of the bridge arm and the lower bridge arm switch tube.

[0030] This topology allows each phase current sensor to obtain more current information through winding. Any M-phase current sensor CSM can obtain the lower bridge arm switch tube T in the left bridge arm connected to the M-phase armature winding. M1 The current i flowing through TM1 , the upper bridge arm diode D in the left bridge arm connected to the M-phase armature winding M1 The current i flowing through DM1 , the upper bridge arm diode D in the right bridge arm connected to the M-phase armature winding M3 The current i flowing through DM3 , the lower bridge arm switch tube T in the right bridge arm connected to the M-phase armature winding M2 The current i flowing through TM2 ,like Figure 2 As shown. The M-phase current sensor takes the positive direction of current as the P pole pointing to the N pole, so the current of the three current sensors is written as:

[0031]

[0032] That is, the current i of the current sensor CSM wound by the bridge arm connected to any M-phase armature winding CSM Written as i CSM =i TM1 -2i DM1 +2i DM3 -i TM2 .

[0033] After adjusting the topology structure, the conduction state of each lower arm switch tube in the H-bridge half-controlled rectifier of the controlled rectifier system is as follows: Figure 3 As shown, the controlled rectifier system of the electrically excited doubly salient generator takes 0° to 360° as a control cycle and is divided into sector 1 of 0° to 120°, sector 2 of 120° to 240° and sector 3 of 240° to 360°. Figure 3 In the figure, m=a, b, c represent the armature windings of phases A, B, and C respectively, and L m is the self-inductance of the M-phase armature winding, L mf is the mutual inductance between the M-phase armature winding and the excitation winding, e mf is the excitation back EMF of the M-phase armature winding, θ is the rotor position angle, θ c is the conduction angle of the switch tube in the sector, Figure 3 When the drive signal for any lower-arm switch is high, the lower-arm switch is on; otherwise, the lower-arm switch is off. Because the three sectors are symmetrical, the following analysis uses the operation within sector 1, which spans 0° to 120°, as an example. The analysis of the other two sectors can be easily derived through analogy.

[0034] 1. Working process of phase A winding in sector 1 of 0° to 120°

[0035] 1. The lower bridge arm switch tube T of the left bridge arm connected to the A-phase armature winding A1 Under normal operating conditions

[0036] In sector 1, e af >0, in order to make the current direction consistent with the polarity of the induced potential, it is necessary to turn on the lower bridge arm switch tube T of the left bridge arm connected to the A-phase armature winding. A1 To increase the current change rate, increase the armature current, and convert it into magnetic field energy for storage. c ] interval, the lower bridge arm switch tube T A1 In the on state, the current loop is: D A4 →A phase winding→T A1 →D A4 ,like Figure 4 As shown. At this time, the A-phase armature winding is in the forward energy storage and current rising stage, and it can be obtained from formula (1):

[0037] i CSA =i TA1 -i TA2 =i a -(-i a )=2i a >0 (2)

[0038] In [θ c ,120°], the lower bridge arm switch tube T A1 Turn off, in order to continue the original positive phase A current of the armature winding, the phase current passes through the diode D A4 and D A1 A freewheeling loop is formed, and the current loop is: load R→D A4 →A phase winding→D A1 →Load R, such as Figure 5 As shown. According to the current loop, the following equation can be written:

[0039] e a -i a r=u o (3)

[0040] Where, e a is the induced voltage of the armature winding of phase A, r is the internal resistance of the armature winding, and the current change rate corresponding to formula (3) is:

[0041]

[0042] Where, e ar is the magnetoresistance back electromotive force of phase A. Considering i a r compared to e af 、e ar and uo is small, so it can be ignored within the error range. Depends on af 、e ar and u o The relationship between the three is due to u o >0, so e af +e ar -u o The amplitude can be positive or negative, making In [θ c ,120°] interval, there are three situations:

[0043] (a) In this case, the phase current i of the A-phase armature winding is a like Figure 6 As shown in (a), i a ≠0, i CSA =-2i DA1 -i TA2 =-2i a -(-i a )=-i a <0.

[0044] (b) and Small, in this case the phase current i of the armature winding of phase A is a like Figure 6 As shown in (b), i a ≠0, i CSA =-2i DA1 -i TA2 =-2i a -(-i a )=-i a <0.

[0045] (c) and In this case, the phase current i of the armature winding of phase A is larger. a like Figure 6 As shown in (c), in this case [θ c ,120°] interval will appear i a After it drops to 0 and remains at 0, this is because when i a When it just drops to 0, e ar and i a r is 0, and substituting it into formula (4) we can see that e af o , that is, the excitation back EMF is less than the output voltage. Since phase A cannot provide energy to the load, i a Keep it at 0. ​

[0046] Combining the three cases, we can see that in [θ c ,120°], when the armature winding of phase A is in the forward freewheeling power generation stage, i CSA ≤0.

[0047] In summary, in sector 1 from 0° to 120°, in [0°,θ c ] interval, when the A-phase armature winding is in the forward energy storage and current rising stage, i CSA =2i a >0. In [θ c ,120°], when the A-phase armature winding is in the forward freewheeling power generation stage, i CSA =-i a ≤0.

[0048] 2. The above analysis does not take into account the phase-commutation overlap of the system. The following analysis is about the phase-commutation process near 0°. To simplify the analysis, the current change rate in this part ignores the small winding internal resistance. Before the phase-commutation at 0°, the system current flows as follows: Figure 7 As shown in Figure 2, if commutation overlap is considered, further analysis should be conducted on this basis.

[0049] Under the APC strategy, T A1 The opening will pass through loop D A4 →A phase winding→T A1 →D A4 Generates positive phase A current. If the positive phase C current has continued to flow to 0 before 0°, then T C2 will be as Figure 8 As shown by loop D C2 →C phase winding→T C2 →D C2 Generate negative C-phase current. If there is still positive C-phase current at 0°, then Figure 9 As shown by diode D C1 and D C4 Commutation, T C2 Will be D C2 Reverse clamped, in zero voltage turn-on state.

[0050] From the above analysis, it can be seen that in sector 1, the current of phase A is not affected by the commutation overlap, and the current waveform is still as Figure 6 shown.

[0051] 3. Analyze T A1 The impact of the failure.

[0052] T A1 During normal operation, [0°,θ c ]In the interval T A1 Drive signal, i a and iCSA The current waveform is as follows Figure 10 As shown in (a) in .

[0053] When T A1 In [0°,θ c ] When a fault occurs in the section, the current loop will be A4 →A phase winding→T A1 →D A4 ” is converted into “load R→D A4 →A phase winding→D A1 →Load R”, the working state of phase A is transformed from the forward energy storage and current rising state to the forward freewheeling power generation state, so that i CSA Changes from a positive value to a negative value.

[0054] When T A1 In [θ c ,360°] section when a fault occurs, T A1 It does not work in this range and has no fault characteristics. However, in the next electrical angle cycle after the fault, [0°,θ c ] interval, the voltage at the A phase terminal u a The expression is as follows:

[0055]

[0056] Among them, e aa is the self-inductance induced potential of phase A, and its value is

[0057] When θ=0°, i a is 0, and substituting it into formula (5) we can get u a =e af According to e af with u o There are two possibilities for the size relationship:

[0058] When e af >u o When , phase A generates electricity in an uncontrolled rectifier mode, such as Figure 10 As shown in (b), i a >0,i CSA Current waveform Figure 10 As shown in (c) in .

[0059] When e af o When , the A-phase winding cannot provide energy to the load, such as Figure 10 As shown in (d), i a Keep it at 0, i CSA The waveform is shown in (e) in FIG10 .

[0060] Therefore, it can be determined that when T​A1 When a fault occurs, the c ]Interval detected i CSA ≤0.

[0061] 2. Working process of C phase winding in sector 1 of 0° to 120°

[0062] In sector 1, e cf <0, similar to the forward energy storage current rising stage, in order to make the current direction consistent with the induced potential polarity, it is necessary to turn on the lower bridge arm switch tube T of the right bridge arm connected to the C phase armature winding. C2 To increase the current change rate, increase the armature current, and convert it into magnetic field energy for storage. c ] interval, the lower bridge arm switch tube T C2 In the on state, the current loop is: D C2 →C phase winding→T C2 →D C2 ,like Figure 8 As shown, at this time, the C-phase armature winding is in the negative energy storage and current rising stage. According to formula (1), we can get i CSC =i TC1 -i TC2 =-(-i c )-(-i c )=2i c <0.

[0063] In [θ c ,120°], the lower bridge arm switch tube T C2 Turn off, in order to continue the original positive C phase current of the armature winding, the phase current passes through the diode D C3 and D C2 A freewheeling loop is formed, and the current loop is: load R→D C2 →C phase winding→D C3 →Load R, such as Figure 11 As shown. At this time, the C-phase armature winding is in the negative freewheeling power generation stage. According to the current loop, the following equation can be written:

[0064] e c -i c r=-u o (6)

[0065] Where, e c is the induced voltage of the C-phase armature winding, r is the internal resistance of the armature winding, and the current change rate corresponding to formula (6) is shown as follows:

[0066]

[0067] Where, e cr is the C phase magnetoresistance back electromotive force. Considering ic r compared to e cf 、e cr and u o is small, so it can be ignored within the error range. Depends on cf 、e cr and u o The relationship between the three is due to

[0068] u o >0, so e cf +e cr -u o The amplitude can be positive or negative, making In [θ c ,120°] interval, there are three situations:

[0069] (a) In this case, the phase current i of the C-phase armature winding is c like Figure 12 As shown in (a), i c ≠0, i CSC =i TC1 +2i DC3 =-(-i c )+2(-i c )=-i c >0.

[0070] (b) and Small, in this case the phase current i of the C-phase armature winding c like Figure 12 As shown in (b), i c ≠0, i CSC =i TC1 +2i DC3 =-(-i c )+2(-i c )=-i c >0.

[0071] (c) and In this case, the phase current i of the C-phase armature winding is larger. c like Figure 12 As shown in (c), in this case [θ c ,120°] interval will appear i c After rising to 0 and remaining at 0, this is because when i c When it just rises to 0, e cr and i c r is 0, and we can get it by substituting it into formula (6).cf o , that is, the amplitude of the excitation back electromotive force is less than u o , so phase C cannot provide energy to the load, i c Keep it at 0.

[0072] From the above three cases, we can see that in [θ c ,120°], when the C-phase armature winding is in the negative freewheeling power generation stage, i CSC ≥0.

[0073] 2. Similar to the A-phase winding, the above analysis does not take into account the system's commutation overlap. Figures 7 to 9 Partial analysis shows that when considering commutation overlap, the current waveform of phase C is related to the end point θ1 of the forward current commutation of phase C in sector 1, and the conduction angle θ c The relationship with θ1 will also have an impact, so in sector 1 [0°, θ c ] interval i c There are three current situations:

[0074] (1) When θ1 = 0°, T C2 Normally, [0°,θ c ]T in the interval C2 Drive signal, i c and i CSC The current waveform is as follows Figure 13 As shown in (a) in .

[0075] (2) When 0°<θ1<θ c When T C2 Normally, [0°,θ c ]T in the interval C2 Drive signal, i c and i CSC The current waveform is as follows Figure 14 As shown in (a) in .

[0076] (3) When θ c When <θ1<120°, T C2 Normally, [0°,θ c ]T in the interval C2 Drive signal, i c and i CSC The current waveform is as follows Figure 15 shown.

[0077] 3. The following analyzes T in the above three cases in turn C2 The impact of open circuit fault.

[0078] (1) In Figure 13 In the case of θ1 = 0° shown​

[0079] When T C2 In [0°,θ c ] When a fault occurs in the section, the current loop will be C2 →C phase winding→T C2 →D C2 ” becomes “Load R→D C2 →C phase winding→D C3 →Load R”, the working state of phase C changes from negative energy storage and current boost to negative freewheeling power generation, i CSC From negative to positive.

[0080] When T C2 In [θ c ,360°] when a fault occurs, due to the interval T C2 Not working, so there is no fault feature. But at T C2 The next electrical angle cycle after the fault occurs [0°,θ c ] interval, the C phase terminal voltage u c The expression is as follows:

[0081]

[0082] Where, e cc is the self-inductance induced potential of phase C, and its value is When θ=0°, i c is 0, and substituting it into formula (8) we can get u c =e cf According to e cf with u o There are two possibilities for the size relationship:

[0083] when|e cf |>u o When , phase C generates electricity in an uncontrolled rectifier mode, such as Figure 13 As shown in (b), i c <0.

[0084] when|e cf | o When , the C-phase winding cannot provide energy to the load, such as Figure 13 As shown in (c), i c Keep it at 0.

[0085] Therefore, in this case, when T C2 When a fault occurs, c ] The fault feature i can be extracted from the interval CSC ≥0.

[0086] (2) In Figure 14 0°<θ1<θ shown​c In the case of

[0087] When T C2 A fault occurs in the interval [0°,θ1]. Considering that the current of phase C is in commutation, the current loop is “load R→D C4 →C phase winding→D C1 →Load R", such as Figure 14 As shown in (b). CSC =-i c <0, it can be found that T C2 D C4 Reverse clamp, so T C2 The fault does not affect the current loop in this section. When θ=θ1, i c =0, from formula (8) we can get u c =e cf According to e cf with u o There are two possibilities for the relationship between the size of |e cf |>u o When the C phase generates electricity in an uncontrolled rectifier mode, i c <0, then Figure 14 As shown in (c), at this time i CSC >0. when|e cf | o When the C phase winding cannot provide energy to the load, i c Keep it at 0, then Figure 14 As shown in (d), at this time i CSC = 0. Therefore, combining the above two possibilities, there is a fault feature i CSC ≥0.

[0088] When T C2 In [θ1,θ c ] If a fault occurs in the interval, the current loop will be “D C2 →C phase winding→T C2 →D C2 ” becomes “Load R→D C2 →C phase winding→D C3 →Load R", such as Figure 14 As shown in (e), the working state of phase C changes from negative energy storage to negative continuous flow power generation, i CSC From negative to positive, such as Figure 14 As shown in (f) in the figure. At this time, there is also a fault feature i CSC ≥0.

[0089] When T C2 In [θ c ,360°] When a fault occurs, due to T C2 ​It does not work in this range, so it will be in the next electrical angle cycle [0°,θ c ] and make the diagnosis according to the above method.

[0090] In summary, in this case, when T C2 When a fault occurs, c ] The fault feature i can be extracted from the interval CSC ≥0.

[0091] (3) In Figure 15 The θ shown c In the case of <θ1<120°

[0092] When T C2 In [0°,θ c ]When a fault occurs in the section, Figure 15 As shown in [0°,θ c ]In the interval i c ≥0, we know that T C2 is clamped, so similar to the above analysis, the fault cannot be detected in this interval.

[0093] When T C2 In [θ c ,360°] When a fault occurs, due to T C2 It does not work in this range, so it will be in the next electrical angle cycle [0°,θ c ] for diagnosis, and from the above we can see that this situation is [0°,θ c ]In the interval T C2 will be clamped, making T C2 The fault will not be affected by the system.

[0094] Therefore, in this case, T C2 The fault has no impact on the system and can be ignored.

[0095] Combining the above three situations, we can know that when 0°≤θ1<θ c In the case of T C2 Faults will have an impact on the system and can occur in [0°,θ c ]Fault feature i is extracted within the interval CSC ≥0.

[0096] Based on the above, T in sector 1 A1 and T C2 The failure analysis can be summarized as follows:

[0097] When T A1 During normal operation, the armature winding of phase A is in [0°,θ c ] is in the positive energy storage and flow increasing stage, i CSA =2ia >0. Phase A armature winding is [θ c ,120°] is in the forward freewheeling power generation stage, i CSA =-i a ≤0. When T A1 When an open circuit fault occurs, the c ] detected in the interval i CSA ≤0.

[0098] When T C2 During normal operation, the C-phase armature winding is in the range [0°,θ c ] is in the negative energy storage flow rising stage, i CSC =2i c <0. The armature winding of phase C is [θ c ,120°] is in the negative freewheeling power generation stage, i CSC =-i c ≥0. And when T C2 When an open circuit fault occurs, the c ] detected in the interval i CSC ≥0.

[0099] For sector 2, T B1 and T A2 The fault analysis of T in sector 3 is similar. C1 and T B2 The fault analysis of the three sectors is similar, so the fault analysis of the three sectors can be summarized as follows:

[0100] Any sector has its corresponding positive working winding Z and negative working winding Q. In the electrical angle interval [θ s ,θ e ], the forward working winding Z is connected to the lower bridge arm switch tube T in the left bridge arm Z1 And the lower bridge arm switch tube T in the right bridge arm connected to the negative working winding Q Q2 Will be in [θ s ,θ s +θ c ] interval, and [θ s +θ c ,θ e ] interval. The positive working winding Z and the negative working winding Q are the two-phase armature windings in the electrically excited double-pole generator:

[0101] For sector 1, the electrical angle range it covers is 0° to 120°. The positive working winding Z of this sector is the A-phase winding, the negative working winding Q is the C-phase winding, and T Z1 =T A1 , T Q2 =TC2 .

[0102] For sector 2, the electrical angle range it covers is 120° to 240°. The positive working winding Z is the B-phase winding, the negative working winding Q is the A-phase winding, and T Z1 =T B1 , T Q2 =T A2 .

[0103] For sector 3, the electrical angle range it covers is 240° to 360°. The positive working winding Z is the C-phase winding, the negative working winding Q is the B-phase winding, and T Z1 =T C1 , T Q2 =T B2 .

[0104] Through the above analysis, it can be determined that the forward working winding Z in each sector is connected to the lower bridge arm switch tube T in the left bridge arm Z1 The lower bridge arm switch tube T of the right bridge arm connected to the negative working winding Q Q2 At the same time, during the conduction process, the current i of the current sensor wound by the bridge arm connected to the forward working winding Z is obtained. CSZ It can detect the lower bridge arm switch tube T in the left bridge arm connected to the forward working winding Z. Z1 Whether an open circuit fault occurs, and the current i of the current sensor wound by the bridge arm connected to the negative working winding Q obtained CSQ It can detect the lower bridge arm switch tube T in the right bridge arm connected to the negative working winding Q Q2 Is there an open circuit fault? Specific information:

[0105] When the lower bridge arm switch tube T in the current sector Z1 And the lower bridge arm switch tube T Q2 At the same time, during the conduction interval, the current i of the current sensor wound by the bridge arm connected to the forward working winding Z is detected. CSZ >0, the lower bridge arm switch tube T Z1 Normal operation. When the current i CSZ When ≤0, the current i can be determined CSZ Abnormal, thus determining the lower bridge arm switch tube T Z1 An open circuit fault has occurred.

[0106] When the lower bridge arm switch tube T in the current sector Z1 And the lower bridge arm switch tube T Q2 At the same time, during the conduction interval, the current i of the current sensor wound around the bridge arm connected to the negative working winding Q is detected. CSQ <0, determine the lower bridge arm switch tube T Q2Normal operation. When the current i CSQ ≥0, the current i can be determined CSQ Abnormal, confirm the lower bridge arm switch tube T Q2 An open circuit fault has occurred.

[0107] However, considering that the current sensor has measurement errors in practice, which makes it impossible to sample zero current, in one embodiment, the current i is not directly CSZ and current i CSQ Instead of comparing with zero current, a positive parameter ε is introduced as the current threshold. In one embodiment, i th <ε no ,i th is the maximum measurement error of the current sensor when the phase current is 0, i no It is the current amplitude of the electrically excited doubly salient generator during no-load operation.

[0108] Then, when the lower bridge arm switch tube in the left bridge arm connected to the positive working winding Z and the lower bridge arm switch tube in the right bridge arm connected to the negative working winding Q are turned on at the same time:

[0109] When the lower bridge arm switch tube T in the current sector Z1 And the lower bridge arm switch tube T Q2 At the same time, the current i is detected in the conduction interval CSZ <ε to determine the current i CSZ Abnormal, thus determining the lower bridge arm switch tube T in the left bridge arm connected to the forward working winding Z in the current sector Z1 An open circuit fault has occurred.

[0110] When the lower bridge arm switch tube T in the current sector Z1 And the lower bridge arm switch tube T Q2 At the same time, the current i is detected in the conduction interval CSQ >-ε to determine the current i CSQ Abnormal, thus determining the lower bridge arm switch tube T in the right bridge arm connected to the negative working winding Q in the current sector Q2 An open circuit fault has occurred.

[0111] For further information, please refer to Figure 10 In sector 1, as shown in (a), when T A1 Normal working time a The current waveform is given by Figure 10 It can be seen that in T A1 During normal operation, CSA The current waveform starts from 0 and gradually increases. Assuming i CSA The time it takes to rise from 0 to ε is t1, and -ε will appear during this period. CSA <ε, this characteristic is consistent with T​​A1 When an open circuit fault occurs, CSA <ε partly coincides, that is, in T A1 Normal work may result in misjudgment. Figure 14 0°<θ1<θ shown c The t2 period and Figure 13 In the case of θ1 = 0°, misjudgment also occurs during the time period t3.

[0112] In order to solve the above misjudgment problem, the lower bridge arm switch tube T is introduced. Z1 The open circuit fault detection time threshold δ1 and the lower bridge arm switch tube T Q2 The open circuit fault detection time threshold δ2 is used, and the optimized fault diagnosis strategy is to switch the lower bridge arm switch T in the left bridge arm connected to the forward working winding Z. Z1 The lower bridge arm switch tube T of the right bridge arm connected to the negative working winding Q Q2 During the conduction process:

[0113] When the current i CSZ <-ε, or, the detected current -ε≤i CSZ <εThe duration t reaches the time threshold δ1 to determine the current i CSZ Abnormal, thus determining the lower bridge arm switch tube T in the left bridge arm connected to the forward working winding Z in the current sector Z1 An open circuit fault has occurred.

[0114] When the current i CSQ >ε, or, current -ε is detected CSQ When the duration t of ≤ε reaches the time threshold δ2, the current i is determined CSQ Abnormal, thus determining the lower bridge arm switch tube T in the right bridge arm connected to the negative working winding Q in the current sector Q2 An open circuit fault has occurred.

[0115] From this we can define the lower bridge arm switch tube T Z1 Fault flag F Z1 And the lower bridge arm switch tube T Q2 Fault flag F Q2 for:

[0116]

[0117] Moreover, since the three phases of the DSEG controlled rectifier system based on HBSCR operate independently, the multi-tube fault can be regarded as the superposition of the single-tube open circuit fault, that is, the multi-tube fault characteristics are the superposition of the single-tube open circuit fault characteristics. Z1 And the lower bridge arm switch tube T Q2 ​The diagnostic results can be superimposed, and the final diagnostic result can be: the lower bridge arm switch tube T in the left bridge arm connected to the forward working winding Z Z1 An open circuit fault occurs, or the negative working winding Q is connected to the lower bridge arm switch tube T of the right bridge arm Q2 An open circuit fault occurs and the switch is in a single-tube fault state. Alternatively, the lower bridge arm switch tube T in the left bridge arm connected to the forward working winding Z Z1 An open circuit fault occurs, and the negative working winding Q is connected to the lower bridge arm switch tube T of the right bridge arm Q2 An open circuit fault occurs and the device is in a double-tube fault state. The diagnostic logic is as follows: Figure 16 shown.

[0118] Next, the lower bridge arm switch tube T Z1 The open circuit fault detection time threshold δ1 and the lower bridge arm switch tube T Q2 The method for determining the value of the open circuit fault detection time threshold δ2 is as follows:

[0119] (1) Lower arm switch tube T Z1 The open circuit fault detection time threshold δ1

[0120] As can be seen from the above analysis, in sector 1, the main CSA The process of the current waveform gradually rising from 0 to ε will generate a A1 Therefore, for any sector, in order to avoid misdiagnosis, it is sufficient to ensure that the time threshold δ1>t1, where t1 is the time when the H-bridge half-controlled rectifier is in normal operation [θ s ,θ s +θ c ]Interval current i CSZ The time it takes to rise from 0 to ε.

[0121] The following methods are used to calculate the time t1:

[0122] Taking sector 1 as an example, the current loop of phase A in the time period t1 is "D A4 →A phase winding→T A1 →D A4 According to Kirchhoff's voltage law (KVL), we can get i a The rates of change are as follows:

[0123]

[0124] Considering that i a Very small, so and i a The amplitude of r is very small and can be ignored within the error range. In addition, due to the excitation self-inductance L f is large and t1 is short, so if Considered unchanged, that is It can be taken as 0 within the error range. Finally, formula (11) is simplified to:

[0125]

[0126] Since t1 is very short, equation (12) can be further discretized as follows:

[0127]

[0128] The same is true for other sectors. Therefore, for the forward working winding Z in any sector, the phase current i of the forward working winding Z can be determined according to Kirchhoff's voltage law. z The change rate of the H-bridge half-controlled rectifier under normal operating conditions is discretized and obtained as follows:

[0129]

[0130] Among them, z=a, b, c respectively represent the cases where the forward working winding Z is the A, B, and C phase armature winding. L zf is the mutual inductance between the forward working winding Z and the excitation winding, L z is the self-inductance of the forward working winding Z, i f is the excitation current, and ω is the rotor electrical angular velocity.

[0131] Then Δt=t1、Δi z =Δi CSZ Substituting / 2=ε / 2 into formula (14) we can obtain:

[0132]

[0133] (2) Lower arm switch tube T Q2 The open circuit fault detection time threshold δ2

[0134] As can be seen from the above analysis, in sector 1, if Figure 13 and Figure 14 The situation will cause the lower bridge arm switch tube T C2 Therefore, the value of the time threshold δ2 needs to take both situations into consideration to ensure that both misdiagnosis situations are excluded. Therefore, the time threshold δ2>max(t2,t3).

[0135] (a) t2 is the end point of the positive current commutation of the negative working winding Q. θ1 is located at T Z1 and T Q2 In the case of the conduction process, when the H-bridge half-controlled rectifier is in normal operation [θ s ,θ s +θc ]Interval current i CSQ The total time taken to rise from -ε to 0 at the end point of forward current commutation θ1 and then fall back to -ε. c It is the conduction angle of the lower bridge arm switch tube of the right bridge arm connected to the negative working winding Q in the current sector.

[0136] Combine Figure 14 The situation is analyzed by taking the C phase winding in sector 1 as an example. Figure 14 It can be seen that t2=t 21 +t 22 ,in:

[0137] t 21 The current loop of phase C during the time period is: load R→D C4 →C phase winding→D C1 →Load R, according to Kirchhoff's voltage law (KVL), we can get i c The rates of change are as follows:

[0138]

[0139] Similar to the above analysis of phase A, within the error range, equation (16) can be simplified to:

[0140]

[0141] Further discretization of (17) yields:

[0142]

[0143] The same is true for other sectors. Therefore, for the negative working winding Q in any sector, the phase current i of the negative working winding Q can be determined according to Kirchhoff's voltage law. q The rate of change before the end point θ1 of the forward current commutation is discretized to obtain:

[0144]

[0145] Among them, q=a, b, c corresponds to the case where the negative working winding Q is the A, B, and C phase armature winding respectively. L qf is the mutual inductance between the negative working winding Q and the excitation winding, L q is the self-inductance of the negative working winding Q, i f is the excitation current, ω is the rotor electrical angular velocity, u o is the output voltage.

[0146] Then Δt=t 21 , Δi q =-Δi CSQ=-εSubstituting into formula (19) we can get:

[0147]

[0148] Similar to the above analysis, according to Kirchhoff's voltage law, the phase current i of the negative working winding Q is determined under the normal operating state of the H-bridge half-controlled rectifier. q The rate of change after the forward current commutation end point θ1 is discretized to obtain:

[0149]

[0150] Set Δt=t 22 , Δi q =-Δi CSQ =-εSubstituting into formula (21) we can get the current i CSQ The time it takes to decrease from 0 at the end point of forward current commutation θ1 to -ε is:

[0151]

[0152] Finally, the time taken can be determined

[0153] (b) t3 is the time when the positive current commutation end point θ1 of the negative working winding Q is at the beginning of the sector, and the H-bridge half-controlled rectifier is in normal operation [θ s ,θ s +θ c ]Interval current i CSQ The time it takes to decrease from 0 to -ε.

[0154] contrast Figure 13 and Figure 14 It can be seen that the current loop in the t3 period is consistent with the above t 22 The same as in the time period, so the phase current i of the negative working winding Q is determined according to Kirchhoff's voltage law. q The change rate of the H-bridge half-controlled rectifier under normal operating conditions is discretized to obtain the form shown in the above formula (21), and then Δt=t3, Δi q =-Δi CSQ =-εSubstituting into the equation, we get:

[0155]

[0156] It can be seen that t3 is consistent with the above t 22 are the same.

[0157] Based on the above calculations, considering that t1, t2, and t3 are very short and all near 0°, we can set:

[0158]

[0159] Among them, L min is the minimum value of the three-phase armature winding self-inductance, L max It is the maximum value of the three-phase armature winding self-inductance.

[0160] The above description is only a preferred embodiment of the present application, and the present application is not limited to the above embodiments. It is understood that other improvements and variations directly derived or imagined by those skilled in the art without departing from the spirit and concept of the present application should be considered to be included in the scope of protection of the present application.

Claims

1. A fault diagnosis method for an H-bridge half-controlled rectifier of an electrically excited doubly salient generator, characterized in that: The lower bridge arm conductor of the left bridge arm connected to any M-phase armature winding in the electrically excited doubly salient generator passes through the M-phase current sensor CSM from the P pole to the N pole and is wound one turn. The upper bridge arm conductor of the left bridge arm connected to the M-phase armature winding passes through the M-phase current sensor CSM from the N pole to the P pole and is wound two turns. The upper bridge arm conductor of the right bridge arm connected to the M-phase armature winding passes through the M-phase current sensor CSM from the P pole to the N pole and is wound two turns. The lower bridge arm conductor of the right bridge arm connected to the M-phase armature winding passes through the M-phase current sensor CSM from the N pole to the P pole and is wound one turn. M=A, B, C represent the three-phase armature windings in the electrically excited doubly salient generator respectively. The positive direction of current is from the midpoint of the right bridge arm connected to any M-phase armature winding to the midpoint of the left bridge arm. The fault diagnosis method for an H-bridge half-controlled rectifier of an electrically excited doubly salient generator comprises: Get the current i of the current sensor wound by the bridge arm connected to the forward working winding Z in the sector where the rotor position angle θ is currently located CSZ , and the current i of the current sensor wound by the bridge arm connected to the negative working winding Q in the current sector CSQ ; The positive working winding Z and the negative working winding Q are two-phase armature windings in the electrically excited doubly salient generator; The lower bridge arm switch tube T in the left bridge arm connected to the forward working winding Z Z1 The lower bridge arm switch tube T of the right bridge arm connected to the negative working winding Q Q2 During the conduction process, when the current i CSZ In case of abnormality, determine the lower bridge arm switch tube T in the left bridge arm connected to the forward working winding Z. Z1 An open circuit fault occurs. When the current i CSQ In case of abnormality, determine the lower bridge arm switch tube T in the right bridge arm connected to the negative working winding Q Q2 An open circuit fault has occurred.

2. The fault diagnosis method for an H-bridge half-controlled rectifier of an electrically excited doubly salient generator according to claim 1, characterized in that: The M-phase current sensor takes the P pole pointing to the N pole as the positive direction of current. The current i of the current sensor wound by the bridge arm connected to any M-phase armature winding is CSM =i TM1 -2i DM1 +2i DM3 -i TM2 , where i TM1 Indicates the lower bridge arm switch tube T in the left bridge arm connected to the M-phase armature winding M1 The current flowing through, i DM1 Indicates the upper bridge arm diode D in the left bridge arm connected to the M-phase armature winding M1 The current flowing through, i DM3 The upper bridge arm diode D in the right bridge arm connected to the M-phase armature winding is shown. M3 The current flowing through, i TM2 Indicates the lower bridge arm switch tube T in the right bridge arm connected to the M-phase armature winding M2 The current flowing through Detection current i CSZ and current i CSQ Whether abnormalities include: When the lower bridge arm switch tube T in the current sector Z1 And the lower bridge arm switch tube T Q2 At the same time, the current i is detected in the conduction interval CSZ <ε to determine the current i CSZ Abnormal, current i detected CSQ >-ε to determine the current i CSQ Exception; where ε is a positive parameter.

3. The fault diagnosis method for an H-bridge half-controlled rectifier of an electrically excited doubly salient generator according to claim 2, characterized in that: Detection current i CSZ and current i CSQ Whether it is abnormal also includes: When the lower bridge arm switch tube T in the current sector Z1 And the lower bridge arm switch tube T Q2 At the same time, the current i is detected in the conduction interval CSZ <-ε, or, the detected current -ε≤i CSZ <εWhen the duration reaches the time threshold δ1, the current i is determined CSZ abnormal; When the lower bridge arm switch tube T in the current sector Z1 And the lower bridge arm switch tube T Q2 At the same time, the current i is detected in the conduction interval CSQ >ε, or, current -ε is detected CSQ When the duration of ≤ε reaches the time threshold δ2, the current i is determined CSQ abnormal.​ 4. The fault diagnosis method for an H-bridge half-controlled rectifier of an electrically excited doubly salient generator according to claim 3, characterized in that: The time threshold δ1>t1, t1 is the current i under the normal operating state of the H-bridge half-controlled rectifier CSZ The time it takes to rise from 0 to ε.

5. The fault diagnosis method for an H-bridge half-controlled rectifier of an electrically excited doubly salient generator according to claim 4, characterized in that: Methods for determining the time t1 include: According to Kirchhoff's voltage law, the phase current i of the forward working winding Z is determined z The change rate of the H-bridge half-controlled rectifier under normal operating conditions is obtained by discretization. Let Δt=t1、Δi z =Δi CSZ / 2=ε / 2Substituting it into in, z=a, b, c respectively represent the case where the forward working winding Z is the A, B, C phase armature winding, L zf is the mutual inductance between the forward working winding Z and the excitation winding, L z is the self-inductance of the forward working winding Z, i f is the excitation current, and ω is the rotor electrical angular velocity.

6. The fault diagnosis method for an H-bridge half-controlled rectifier of an electrically excited doubly salient generator according to claim 3, characterized in that: Time threshold δ2>max(t2,t3), where: t2 is the end point of the positive current commutation of the negative working winding Q. θ1 is located at T Z1 and T Q2 In the case of the conduction process, the H-bridge half-controlled rectifier is in normal operation when the current i CSQ The total time taken to rise from -ε to 0 at the end point of forward current commutation θ1 and then fall back to -ε; where θ c It is the lower bridge arm switch tube T of the right bridge arm connected to the negative working winding Q Q2 The conduction angle of the switch in the current sector; t3 is the current i in the normal operation state of the H-bridge half-controlled rectifier when the positive current commutation end point θ1 of the negative working winding Q is at the beginning of the sector. CSQ The time it takes to decrease from 0 to -ε.

7. The fault diagnosis method for an H-bridge half-controlled rectifier of an electrically excited doubly salient generator according to claim 6, characterized in that: Methods for determining the time t2 include: According to Kirchhoff's voltage law, the phase current i of the negative working winding Q is determined under the normal operating state of the H-bridge half-controlled rectifier. q The rate of change before the forward current commutation end point θ1 is discretized to obtain Set Δt=t 21 , Δi q =-Δi CSQ =-εSubstitute to get the current i CSQ The time taken to rise from -ε to 0 at the end point of forward current commutation θ1 According to Kirchhoff's voltage law, the phase current i of the negative working winding Q is determined under the normal operating state of the H-bridge half-controlled rectifier. q The rate of change after the forward current commutation end point θ1 is discretized to obtain Set Δt=t 22 , Δi q =-Δi CSQ =-εSubstitute to get the current i CSQ The time it takes to decrease from 0 at the end point of forward current commutation θ1 to -ε Determine the time Among them, q=a, b, c respectively represent the negative working winding Q is the A, B, C phase armature winding, L qf is the mutual inductance between the negative working winding Q and the excitation winding, L q is the self-inductance of the negative working winding Q, i f is the excitation current, ω is the rotor electrical angular velocity, u o is the output voltage.

8. The fault diagnosis method for an H-bridge half-controlled rectifier of an electrically excited doubly salient generator according to claim 6, characterized in that: Methods for determining the time t3 include: According to Kirchhoff's voltage law, the phase current i of the negative working winding Q is determined q The change rate of the H-bridge half-controlled rectifier under normal operating conditions is obtained by discretization. Set Δt=t3, Δi q =-Δi CSQ =-εSubstitute into the equation to get Among them, q=a, b, c respectively represent the negative working winding Q is the A, B, C phase armature winding, L qf is the mutual inductance between the negative working winding Q and the excitation winding, L q is the self-inductance of the negative working winding Q, i f is the excitation current, and ω is the rotor electrical angular velocity.

9. The fault diagnosis method for an H-bridge half-controlled rectifier of an electrically excited doubly salient generator according to claim 2, characterized in that: i th <ε no ,i th is the maximum measurement error of the current sensor when the phase current is 0, i no It is the current amplitude of the electrically excited doubly salient generator during no-load operation.​ 10. The fault diagnosis method for an H-bridge half-controlled rectifier of an electrically excited doubly salient generator according to claim 1, characterized in that: In the sector where the rotor position angle θ is currently located: The forward working winding Z is connected to the lower bridge arm switch tube T in the left bridge arm Z1 An open circuit fault occurs, or The negative working winding Q is connected to the lower bridge arm switch tube T of the right bridge arm. Q2 An open circuit fault occurs and the device is in a single-tube fault state; Alternatively, the forward working winding Z is connected to the lower bridge arm switch tube T in the left bridge arm Z1 An open circuit fault occurs, and the negative working winding Q is connected to the lower bridge arm switch tube T of the right bridge arm Q2 An open circuit fault occurs and the circuit is in a double-tube fault state.

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