Open-circuit fault diagnosis method for switch tube of open-winding SDSEM driving system

Abstract

The invention discloses an open-winding SDSEM driving system switch tube open-circuit fault diagnosis method, and relates to the field of aviation motor control, and the method comprises the steps: building a mixed logic dynamic model of p-phase armature winding current of an open-winding SDSEM based on a voltage equation of a sine-type electro-magnetic doubly salient motor, observing in real time to obtain the observation current of the p-phase armature winding, and determining the phase current of the p-phase armature winding and the current residual of the observation current of the p-phase armature winding; determining a fault switch tube pair connected with the p-phase armature winding according to positive and negative values of the current residual error; and controlling the on-off relationship of the two switch tubes in the fault switch tube pair so as to inject a diagnosis pulse by using the motor back electromotive force, and determining the switch tube with an open-circuit fault according to the response current of the p-phase armature winding after the diagnosis pulse is injected. According to the open-circuit fault diagnosis method based on combination of the hybrid logic dynamic model and diagnosis pulse self-injection, the diagnosis speed is remarkably increased while single-tube and double-tube fault positioning is achieved.

Description

Technical Field

[0001] The present application relates to the field of aviation motor control, and in particular to a method for diagnosing an open-circuit fault of a switch tube in an open-winding SDSEM drive system. Background Art

[0002] Sinusoidal Doubly Salient Electromagnetic Machine (SDSEM) is a new type of reluctance motor with the advantages of simple rotor structure, low manufacturing cost, strong high-temperature and high-speed operation capability, and timely demagnetization in case of fault. Its torque pulsation is smaller than that of traditional electrically excited doubly salient motor. It has broad application prospects in high-requirement fields such as aviation, new energy power generation, and electric vehicles.

[0003] In order to ensure the stable performance of the sinusoidal electrically excited double-pole motor, the operating performance and reliability of the motor drive system are crucial. Compared with the single-inverter motor drive system, the open-winding motor drive system of the dual inverter has a wider speed range and stronger fault-tolerant operation capability, but because the number of switch tubes has doubled, the probability of failure has also increased. In particular, the open-circuit failure of the switch tube seriously affects the performance of the motor system and even causes damage to the motor system.

[0004] Traditional fault diagnosis methods such as unipolar disturbance or actively changing the operation mode of the faulty phase bridge arm can only perform single-tube open-circuit fault diagnosis, and the positioning accuracy is not high. At present, there is no switch tube open-circuit fault diagnosis method for the open-winding motor drive system of the sinusoidal electrically excited double-pole motor. Summary of the invention

[0005] In view of the above problems and technical requirements, this application proposes a method for diagnosing open-circuit faults of switch tubes in an open-winding SDSEM drive system. The technical solution of this application is as follows:

[0006] A method for diagnosing an open-circuit fault of a switch tube in an open-winding SDSEM drive system comprises the following steps:

[0007] The main power converter in the open-winding SDSEM drive system includes two three-bridge-arm inverters. One end of the three-phase armature windings A, B, and C of the open-winding SDSEM is respectively connected to the midpoint of the three bridge arms in one three-bridge-arm inverter, and the other end of the three-phase armature windings A, B, and C is respectively connected to the midpoint of the three bridge arms in another three-bridge-arm inverter. The open-winding SDSEM drive system switch tube open circuit fault diagnosis method includes:

[0008] Based on the voltage equation of the sinusoidal electrically excited doubly salient motor, a hybrid logic dynamic model of the p-phase armature winding of the open winding SDSEM is constructed. The hybrid logic dynamic model represents the current observation value of the p-phase armature winding. The relationship between the switch states of the two bridge arms connected to the p-phase armature winding; where p = a, b, c represents the A, B, and C-phase armature windings respectively;

[0009] Based on the hybrid logic dynamic model of the p-phase armature winding, the observed current of the p-phase armature winding is obtained by real-time observation. And determine the phase current i of the p-phase armature winding p Its observed current The current residual

[0010] When the residual current of the p-phase armature winding If the error is within 0, it is determined that the switch tubes in the two bridge arms connected to the p-phase armature winding are working properly. Otherwise, according to the current residual The positive or negative value of determines the faulty switch tube pair connected to the p-phase armature winding, the faulty switch tube pair is a switch tube pair including a switch tube open circuit fault among the two switch tube pairs connected to the p-phase armature winding, each switch tube pair includes an upper bridge arm switch tube in one bridge arm connected to the p-phase armature winding and a lower bridge arm switch tube in another bridge arm;

[0011] When the motor electrical angle θ is within the conduction electrical angle range of the non-fault switch pair of the p-phase armature winding, the two switch tubes of the non-fault switch pair connected to the p-phase armature winding are kept turned off, and the on-off relationship of the two switch tubes in the faulty switch pair is controlled to utilize the motor back electromotive force to inject a diagnostic pulse, and the switch tube with an open circuit fault in the faulty switch pair is determined based on the response current of the p-phase armature winding after the diagnostic pulse is injected.

[0012] A further technical solution is that the hybrid logic dynamic model of the three-phase armature winding of the open-winding SDSEM is:

[0013]

[0014] in, Observed current of three-phase armature winding Observe the differential of the current i f is the field winding current, R p is the resistance of the p-phase armature winding, L p is the self-inductance of the p-phase armature winding, L pf is the mutual inductance between the p-phase armature winding and the field winding; δ = [δ a ,δ b ,δ c ] TIt is the discrete input quantity under the motor electrical angle θ when the open winding SDSEM drive system is working normally. δ ip It is the phase current direction of the p-phase armature winding at the real-time motor electrical angle θ when the open-winding SDSEM drive system is working normally. Indicates the ip Negate; S p1 It is the upper bridge arm switch tube T of the first bridge arm connected to the p-phase armature winding p1 The drive signal at the motor electrical angle θ, S p2 It is the lower bridge arm switch tube T of the second bridge arm connected to the p-phase armature winding p2 The drive signal at the motor electrical angle θ, S p3 It is the lower bridge arm switch tube T of the first bridge arm connected to the p-phase armature winding p3 The drive signal at the motor electrical angle θ, S p4 It is the upper bridge arm switch tube T of the second bridge arm connected to the p-phase armature winding p4 The driving signal at the motor electrical angle θ, the phase current i of the p-phase armature winding p The current flowing from the midpoint of the first bridge arm to the midpoint of the second bridge arm is regarded as the positive direction of the current, U dc is the DC bus voltage; for any parameter j∈[1,4], the drive signal S pj =1 means the switch is on, the drive signal S pj =0 means the switch is turned off. Indicates the driving signal S pj Negate, [] T Represents matrix transpose.

[0015] Its further technical solution is to use the current residual The positive or negative value of determines the fault switch tube pair connected to the p-phase armature winding, including:

[0016] When the current residual When the error range exceeds 0 and is less than 0, it is determined that the switch tube pair consisting of the upper bridge arm switch tube of the first bridge arm and the lower bridge arm switch tube of the second bridge arm connected to the p-phase armature winding is a faulty switch tube pair;

[0017] When the current residual When the error range exceeds 0 and is greater than 0, it is determined that the switch tube pair formed by the lower bridge arm switch tube of the first bridge arm and the upper bridge arm switch tube of the second bridge arm connected to the p-phase armature winding is a faulty switch tube pair.

[0018] A further technical solution is that the switch tube having an open circuit fault in the faulty switch tube pair is determined according to the response current of the p-phase armature winding after the diagnostic pulse is injected, and includes:

[0019] The two switch tubes in the fault switch tube pair connected to the p-phase armature winding are controlled to conduct one tube at a time. When the response current of the p-phase armature winding in the process of single tube conduction reaches the threshold value i th When the faulty switch tube is detected, it is determined that the switched-off switch tube has an open circuit fault and the switched-on switch tube is operating normally;

[0020] When the response current of the p-phase armature winding during the single-tube conduction process does not reach the threshold value i th When , it is determined that both switch tubes in the faulty switch tube pair have open circuit faults.

[0021] A further technical solution is to construct a hybrid logic dynamic model of the three-phase armature winding including:

[0022] The voltage equation for determining the sinusoidal electrically excited double-pole motor is:

[0023]

[0024] Where d is the differential operator; solving the voltage equation of the sinusoidal electrically excited double-pole motor obtains the current equation of the sinusoidal electrically excited double-pole motor:

[0025]

[0026] According to the working principle of the main power converter in the open-winding SDSEM drive system, the p-phase terminal voltage U is determined when the open-winding SDSEM drive system is working normally. p1p2 Substituting the expression into the current equation of the sinusoidal electrically excited doubly salient motor, the hybrid logic dynamic model of the three-phase armature winding is obtained, and the discrete input quantity δ=[δ a ,δ b ,δ c ] T =[U a1a2 ,U b1b2 ,U c1c2 ] T and:

[0027]

[0028] A further technical solution is that the method for diagnosing an open-circuit fault of a switch tube in an open-winding SDSEM drive system further includes:

[0029] According to the working principle of the main power converter in the open-winding SDSEM drive system, the p-phase fault terminal voltage U′ of the open-winding SDSEM drive system under different switch tube open-circuit fault conditions is determined. p1p2Substitute the expression into the current equation of the sinusoidal electrically excited doubly salient pole motor to obtain the current state equation of the three-phase armature winding under the corresponding switch tube open circuit fault condition: δ′=[δ′ a ,δ′ b ,δ′ c ] T =[U′ a1a2 ,U′ b1b2 ,U′ c1c2 ] T It is the discrete input quantity of the open-winding SDSEM drive system with the motor electrical angle θ under different switch tube open-circuit fault conditions;

[0030] The hybrid logic dynamic model of the three-phase armature winding is subtracted from the current state equation of the three-phase armature winding under the corresponding switch tube open circuit fault condition to obtain the expression of the current residual under the corresponding switch tube open circuit fault condition: And determine the positive and negative value of the current residual, where: is the current residual of the p-phase armature winding.

[0031] A further technical solution is to determine the p-phase fault terminal voltage U′ when different switch tube open circuit faults occur in the first bridge arm and the second bridge arm connected to the p-phase armature winding. p1p2 The expressions include:

[0032]

[0033] Determine the expression of the current residual under different switch tube open circuit fault conditions and determine the positive and negative values ​​of the current residual, including:

[0034] Determine the upper bridge arm switch tube T of the first bridge arm connected to the p-phase armature winding p1 When a single tube fails, the current residual of the p-phase armature winding is expressed as And solve it to get Sure

[0035] Determine the lower bridge arm switch tube T of the second bridge arm connected to the p-phase armature winding p2 When a single tube fails, the current residual of the p-phase armature winding is expressed as And solve it to get Sure

[0036] Determine the upper bridge arm switch tube T of the first bridge arm connected to the p-phase armature winding p1 And the lower bridge arm switch tube T of the second bridge arm p2 When the double-tube open circuit fault occurs, the expression of the current residual of the p-phase armature winding is: And solve it to get Sure

[0037] Determine the lower bridge arm switch tube T of the first bridge arm connected to the p-phase armature winding p3 When a single tube fails, the current residual of the p-phase armature winding is expressed as And solve it to get Sure

[0038] Determine the upper bridge arm switch tube T of the second bridge arm connected to the p-phase armature winding p4 When a single tube fails, the current residual of the p-phase armature winding is expressed as And solve it to get Sure

[0039] Determine the lower bridge arm switch tube T of the first bridge arm connected to the p-phase armature winding p3 And the upper bridge arm switch tube T of the second bridge arm p4 When the double-tube open circuit fault occurs, the expression of the current residual of the p-phase armature winding is: And solve it to get Sure

[0040] The beneficial technical effects of this application are:

[0041] The present application proposes a method for diagnosing the open-circuit fault of the switch tube of an open-winding SDSEM drive system by constructing a hybrid logic dynamic model to observe the motor phase current in real time. The switch states of various open-circuit fault conditions are analyzed for the special topological structure of the open-winding SDSEM drive system, and the current residual between the motor phase current and the observed current is derived. The faulty switch tube pair is located by detecting the positive and negative values ​​of the current residual in real time. Since the motor phase current during the operation of the open-winding SDSEM drive system is observed in real time, the faulty switch tube pair can be located at the moment of the open-circuit fault, which greatly improves the speed of fault detection compared to the existing methods and effectively ensures the safety and stability of the motor operation.

[0042] The method of self-injection of diagnostic pulses can detect not only double-tube faults but also single-tube faults, and can accurately detect the specific switch tube with open circuit faults. It does not rely on motor parameters and the assistance of other additional hardware and equipment. It only uses the motor back electromotive force of the open-winding SDSEM drive system itself to accurately locate the faulty switch tube without determining the diagnostic pulse width. It has high reliability and is easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a topological diagram of an open-winding sinusoidal electrically excited double-pole motor drive system.

[0044] Figure 2 The present invention is a flow chart of a method for diagnosing an open-circuit fault of a switch tube in an open-winding sinusoidal electrically excited double-pole motor drive system.

[0045] Figure 3 The diagram is a conduction logic diagram and phase current waveform diagram of a sinusoidal electrically excited double-pole motor according to an embodiment.

[0046] Figure 4 This is a schematic diagram of the switch tube pair connected to the A-phase armature winding.

[0047] Figure 5 It is T P1 In case of an open circuit fault, the diagnostic pulse is injected into the current flow path.

[0048] Figure 6 It is T P2 In case of an open circuit fault, the diagnostic pulse is injected into the current flow path.

[0049] Figure 7 It is T P1 The motor back EMF and response current after the diagnostic pulse is injected during an open circuit fault.

[0050] Figure 8 It is T P2 The motor back EMF and response current after the diagnostic pulse is injected during an open circuit fault.

[0051] Fig. 9 It is T P1 and T P2 The motor back EMF and response current after the diagnostic pulse is injected during an open circuit fault.

[0052] Fig.10 It is the control block diagram of the open-winding SDSEM drive system. DETAILED DESCRIPTION

[0053] The specific implementation of the present application is further described below in conjunction with the accompanying drawings.

[0054] Compared with the star connection topology of the traditional sinusoidal electric excitation double-pole motor drive system, the open-winding SDSEM drive system of the present application opens the neutral point of the three-phase armature winding. The specific structure is as follows: Figure 1As shown in the figure, the main power converter in the open-winding SDSEM drive system includes two three-bridge-arm inverters. One end of the three-phase armature windings A, B, and C of the open-winding SDSEM is connected to the midpoint of the three bridge arms in one three-bridge-arm inverter, and the other end of the three-phase armature windings A, B, and C is connected to the midpoint of the three bridge arms in another three-bridge-arm inverter. A total of four switch tubes are connected to the two ends of each phase armature winding, and each switch tube is anti-parallel connected to a freewheeling diode. Compared with the single inverter structure of the traditional sinusoidal electromagnetic double-pole motor drive system, the open-winding SDSEM drive system has better fault tolerance and flexibility. When the switch tube of a certain inverter fails, the lower bridge arm of each phase of the inverter can be turned on, while the other inverter remains normal. At this time, the dual inverter system changes to a single inverter working state, which can achieve constant torque half-speed operation, thereby ensuring the safe operation of the system.

[0055] Based on the above open-winding SDSEM drive system structure, this application proposes a method for diagnosing open-circuit faults of switch tubes in an open-winding SDSEM drive system. Please refer to Figure 2 The flowchart shown in the figure has the following specific steps:

[0056] Step 1: Use hybrid system theory to construct a hybrid logic dynamic model of the p-phase armature winding of the open-winding SDSEM based on the voltage equation of the sinusoidal electromagnetic doubly salient motor. The hybrid logic dynamic model represents the current observation value of the p-phase armature winding. The relationship between the switch states of the two bridge arms connected to the p-phase armature winding; where p=a, b, c represents the A, B, and C-phase armature windings respectively.

[0057] The hybrid logic dynamic model of the three-phase armature winding of the open-winding SDSEM is:

[0058]

[0059] in, Observed current of three-phase armature winding Observe the differential of the current i f is the field winding current, R p is the resistance of the p-phase armature winding, L p is the self-inductance of the p-phase armature winding, L pf is the mutual inductance between the p-phase armature winding and the field winding; δ = [δ a ,δ b ,δ c ] T It is the discrete input quantity under the motor electrical angle θ when the open winding SDSEM drive system is working normally. δ ipIt is the phase current direction of the p-phase armature winding at the real-time motor electrical angle θ when the open-winding SDSEM drive system is working normally.

[0060] Indicates the ip Negate, i p is the phase current of the p-phase armature winding, i p >0 indicates that the phase current of the p-phase armature winding is conducting in the forward direction, i p <0 means the phase current of the p-phase armature winding is negatively conducting; S p1 It is the upper bridge arm switch tube T of the first bridge arm connected to the p-phase armature winding p1 The drive signal at the motor electrical angle θ, S p2 It is the lower bridge arm switch tube T of the second bridge arm connected to the p-phase armature winding p2 The drive signal at the motor electrical angle θ, S p3 It is the lower bridge arm switch tube T of the first bridge arm connected to the p-phase armature winding p3 The drive signal at the motor electrical angle θ, S p4 It is the upper bridge arm switch tube T of the second bridge arm connected to the p-phase armature winding p4 The driving signal at the motor electrical angle θ, the phase current i of the p-phase armature winding p The current flowing from the midpoint of the first bridge arm to the midpoint of the second bridge arm is regarded as the positive direction of the current, U dc is the DC bus voltage; for any parameter j∈[1,4], the drive signal S pj =1 means the switch is on, the drive signal S pj =0 means the switch is off, S pj Indicates the driving signal S pj Negate, [] T Represents matrix transpose.

[0061] In one embodiment, the specific process of constructing the hybrid logic dynamic model of the three-phase armature winding is as follows:

[0062] (1) Determine the voltage equation of the sinusoidal electrically excited doubly salient pole motor. The specific expression of the voltage equation is:

[0063]

[0064] Among them, d is the differential operator, i f is the field winding current, R p is the resistance of the p-phase armature winding, L p is the self-inductance of the p-phase armature winding, L pf is the mutual inductance between the p-phase armature winding and the field winding, U p1p2 is the p-phase terminal voltage.

[0065] (2) Solving the voltage equation of the sinusoidal electrically excited double-pole motor to obtain the current equation of the sinusoidal electrically excited double-pole motor is:

[0066]

[0067] (3) According to the working principle of the main power converter in the open-winding SDSEM drive system, the p-phase terminal voltage U is determined when the open-winding SDSEM drive system is working normally. p1p2 Substituting the expression into the current equation of the sinusoidal electrically excited doubly salient pole motor, the hybrid logic dynamic model of the three-phase armature winding is obtained.

[0068] First, the operation mode of the main power converter and motor of the open-winding SDSEM drive system structure is analyzed to establish the relationship between the terminal voltage, the inverter switch state, and the phase current flow direction. The conduction logic and phase current waveform of the sinusoidal electric excitation double-pole motor under vector control are shown in Figure 2. Figure 3 As shown. Figure 3 Taking the conduction mode shown in the figure as an example, the current changes of the switch tube of the open-winding SDSEM drive system under different states are analyzed.

[0069] The p-phase terminal voltage of the open-winding SDSEM drive system when it is working normally under the action of the drive signal can be expressed as follows:

[0070] If i p >0,δ ip =1, S p1 =1,S p2 =1, then U a1a2 =U dc ;

[0071] If i p >0,δ ip =1, S p1 =0,S p2 =0, then U a1a2 =-U dc ;

[0072] If i p >0,δ ip =1, S p1 =1,S p2 =0, then U a1a2 =0;

[0073] If i p >0,δ ip =1, S p1 =0,S p2 =1, then U a1a2 =0;

[0074] If ip <0,δ ip =0, S p3 =1,S p4 =1, then U a1a2 =-U dc ;

[0075] If i p <0,δ ip =0, S p3 =0,S p4 =0, then U a1a2 =U dc ;

[0076] If i p <0,δ ip =0, S p3 =1,S p4 =0, then U a1a2 =0;

[0077] If i p <0,δ ip =0, S p3 =0,S p4 =1, then U a1a2 =0.

[0078] Among them, δ ip It is the phase current direction of the p-phase armature winding at the real-time motor electrical angle θ when the open-winding SDSEM drive system is working normally. i p >0 indicates that the phase current of the p-phase armature winding is conducting in the forward direction, i p <0 means the phase current of the p-phase armature winding is negatively conducting, U dc is the DC bus voltage.

[0079] Based on the above analysis results, the three-phase terminal voltage of the open-winding SDSEM drive system when it is working normally under the action of the drive signal is expressed as:

[0080]

[0081] Phase current i of open winding SDSEM drive system during normal operation p Equal to the observed current Substituting formula (4) into formula (3), the expression of the current differential equation of the three-phase armature winding is obtained as follows:

[0082]

[0083] The hybrid logic dynamic model of the three-phase armature winding is obtained by simplifying formula (5), and the discrete input quantity δ=[δ a ,δb ,δ c ] T =[U a1a2 ,U b1b2 ,U c1c2 ] T , [] T Represents matrix transpose.

[0084] Step 2: Based on the hybrid logic dynamic model of the p-phase armature winding, real-time observation is performed to obtain the observed current of the p-phase armature winding. And determine the phase current i of the p-phase armature winding obtained in real time p Its observed current The current residual

[0085] Step 3: Due to the influence of sampling error, the current residual between the actual phase current and the observed current fluctuates around 0. Therefore, when the current residual of the p-phase armature winding If the error is within 0, it is determined that the switch tubes in the two bridge arms connected to the p-phase armature winding are working properly. Otherwise, according to the current residual The positive or negative value of determines the faulty switch tube pair connected to the p-phase armature winding. The faulty switch tube pair is a switch tube pair including a switch tube open circuit fault in the two switch tube pairs connected to the p-phase armature winding. Each switch tube pair includes an upper bridge arm switch tube in one bridge arm connected to the p-phase armature winding and a lower bridge arm switch tube in another bridge arm. The switch tube pair connected to the A-phase armature winding is as follows: Figure 4 shown.

[0086] In one embodiment, by analyzing the p-phase fault terminal voltage U′ under different switch tube open circuit fault conditions p1p2 To determine the positive and negative value of the current residual, the specific process is as follows:

[0087] According to the working principle of the main power converter in the open-winding SDSEM drive system, the p-phase fault terminal voltage U′ of the open-winding SDSEM drive system under different switch tube open-circuit fault conditions is determined. p1p2 expression.

[0088] By analyzing the current variation of the open-winding SDSEM drive system under different switch tube open-circuit fault conditions, it is found that the p-phase fault terminal voltage of the open-winding SDSEM drive system when an open-circuit fault occurs under the action of the drive signal can be expressed as follows:

[0089] T p1 Single tube open circuit fault:

[0090] If i p >0,δ ip =1, S p1 =1,Sp2 =1, then U a1a2 =0;

[0091] If i p >0,δ ip =1, S p1 =0,S p2 =0, then U a1a2 =-U dc ;

[0092] If i p >0,δ ip =1, S p1 =1,S p2 =0, then U a1a2 =-U dc ;

[0093] If i p >0,δ ip =1, S p1 =0,S p2 =1, then U a1a2 =0;

[0094] T p2 Single tube open circuit fault:

[0095] If i p >0,δ ip =1, S p1 =1,S p2 =1, then U a1a2 =0;

[0096] If i p >0,δ ip =1, S p1 =0,S p2 =0, then U a1a2 =-U dc ;

[0097] If i p >0,δ ip =1, S p1 =1,S p2 =0, then U a1a2 =0;

[0098] If i p >0,δ ip =1, S p1 =0,S p2 =1, then U a1a2 =-U dc ;

[0099] T p1 and T p2 Double tube open circuit fault:

[0100] Young p >0,δ ip = 1, S p1 = 1, S p2 = 1, Rule U a1a2 =-U dc ;

[0101] Young p >0,δ ip = 1, S p1 = 0, S p2 = 0, Rule U a1a2 =-U dc ;

[0102] Young p >0,δ ip = 1, S p1 = 1, S p2 = 0, Rule U a1a2 =-U dc ;

[0103] Young p >0,δ ip = 1, S p1 = 0, S p2 = 1, Rule U a1a2 =-U dc ;

[0104] T p3 South pipe failure:

[0105] Young p <0,δ ip = 0, S p3 = 1, S p4 = 1, Rule U a1a2 = 0;

[0106] Young p <0,δ ip = 0, S p3 = 0, S p4 = 0, Rule U a1a2 = U dc ;

[0107] Young p <0,δ ip = 0, S p3 = 1, S p4 = 0, Rule U a1a2 = U dc ;

[0108] Young p <0,δ ip = 0, S p3 = 0, S p4=1, then U a1a2 =0;

[0109] T p4 Single tube open circuit fault:

[0110] If i p <0,δ ip =0, S p3 =1,S p4 =1, then U a1a2 =0;

[0111] If i p <0,δ ip =0, S p3 =0,S p4 =0, then U a1a2 =U dc ;

[0112] If i p <0,δ ip =0, S p3 =1,S p4 =0, then U a1a2 =0;

[0113] If i p <0,δ ip =0, S p3 =0,S p4 =1, then U a1a2 =U dc ;

[0114] T p3 and T p4 Double tube open circuit fault:

[0115] If i p <0,δ ip =0, S p3 =1,S p4 =1, then U a1a2 =U dc ;

[0116] If i p <0,δ ip =0, S p3 =0,S p4 =0, then U a1a2 =U dc ;

[0117] If i p <0,δ ip =0, S p3 =1,S p4 =0, then U a1a2 =U dc ;

[0118] If i p <0,δ ip =0, S p3 =0,S p4 =1, then U a1a2 =U dc ;

[0119] Based on the above analysis results, the three-phase fault terminal voltage of the open-winding SDSEM drive system when an open-circuit fault occurs under the action of the drive signal is expressed as:

[0120]

[0121] Substituting formula (6) into the current equation of the sinusoidal electrically excited doubly salient pole motor (3), the current state equation of the three-phase armature winding under the corresponding switch tube open circuit fault is obtained: δ′ is the discrete input quantity of the open-winding SDSEM drive system under different switch tube open-circuit fault conditions with the motor electrical angle θ and δ′=[δ′ a ,δ′ b ,δ′ c ] T =[U′ a1a2 ,U′ b1b2 ,U′ c1c2 ] T .

[0122] The hybrid logic dynamic model of the three-phase armature winding is subtracted from the current state equation of the three-phase armature winding under the corresponding switch tube open circuit fault condition to obtain the expression of the current residual under the corresponding switch tube open circuit fault condition: And determine the positive and negative value of the current residual, where: is the current residual of the p-phase armature winding, i is the phase current of the three-phase armature winding and i=[i a ,i b ,i c ] T , is the observed current of the three-phase armature winding and

[0123] Specifically, determining the expression of the current residual under different switch tube open circuit fault conditions and determining whether the current residual is positive or negative includes:

[0124] Determine the upper bridge arm switch tube T of the first bridge arm connected to the p-phase armature winding p1 When a single-tube open-circuit fault occurs, the expression for the current residual of the p-phase armature winding is:

[0125]

[0126] Solving the differential equation of formula (7) yields:

[0127]

[0128] Normally, when t=0, set δ′ is equal to δ, and the current residual is also zero accordingly; when t>0, due to T p1 When a single tube fails p >0,δ ip =1, so in formula (8) From this we can infer Since the current residual cannot be equal to 0 in the event of a fault, T p1 Current residual error when single tube open circuit fault

[0129] Determine the lower bridge arm switch tube T of the second bridge arm connected to the p-phase armature winding p2 When a single-tube open-circuit fault occurs, the expression for the current residual of the p-phase armature winding is:

[0130]

[0131] Solving the differential equation of formula (9) yields:

[0132]

[0133] Under normal circumstances, when t=0, When t>0, due to T p2 When a single tube fails p >0,δ ip =1, so in formula (10) and From this we can infer Since the current residual cannot be equal to 0 in the event of a fault, T p2 Current residual error when single tube open circuit fault

[0134] Determine the upper bridge arm switch tube T of the first bridge arm connected to the p-phase armature winding p1 And the lower bridge arm switch tube T of the second bridge arm p2 When the double-tube open circuit fault occurs, the expression of the current residual of the p-phase armature winding is:

[0135]

[0136] Solving the differential equation of formula (11) yields:

[0137]

[0138] Under normal circumstances, when t=0, When t>0, due to T p1 and T p2 Double tube open circuit fault p >0,δ ip =1, so in formula (12) and From this we can infer Since the current residual cannot be equal to 0 in the event of a fault, T p1 and T p2 Current residual error when double tube open circuit fault occurs

[0139] Determine the lower bridge arm switch tube T of the first bridge arm connected to the p-phase armature winding p3 When a single-tube open-circuit fault occurs, the expression for the current residual of the p-phase armature winding is:

[0140]

[0141] Solving the differential equation of formula (13) yields:

[0142]

[0143] Under normal circumstances, when t=0, When t>0, due to T p3 When a single tube fails p <0,δ ip =0, so in formula (14) and From this we can infer Since the current residual cannot be equal to 0 in the event of a fault, T p3 Current residual error when single tube open circuit fault

[0144] Determine the upper bridge arm switch tube T of the second bridge arm connected to the p-phase armature winding p4 When a single-tube open-circuit fault occurs, the expression for the current residual of the p-phase armature winding is:

[0145]

[0146] Solving the differential equation of formula (15) yields:

[0147]

[0148] Under normal circumstances, when t=0, When t>0, due to T p4 When a single tube fails p <0,δ ip=0, so in formula (16) and From this we can infer Since the current residual cannot be equal to 0 in the event of a fault, T p4 Current residual error when single tube open circuit fault

[0149] Determine the lower bridge arm switch tube T of the first bridge arm connected to the p-phase armature winding p3 And the upper bridge arm switch tube T of the second bridge arm p4 When the double-tube open circuit fault occurs, the expression of the current residual of the p-phase armature winding is:

[0150]

[0151] Solving the differential equation of formula (17) yields

[0152]

[0153] Under normal circumstances, when t=0, When t>0, due to T p3 and T p4 Double tube open circuit fault p <0,δ ip =0, so in formula (18) and From this we can infer Since the current residual cannot be equal to 0 in the event of a fault, T p3 and T p4 Current residual error when double tube open circuit fault occurs

[0154] Based on the above derivation process, according to the current residual The positive or negative value of determines the fault switch tube pair connected to the p-phase armature winding: When the error range exceeds 0 and is less than 0, it is determined that the switch pair consisting of the upper bridge arm switch of the first bridge arm and the lower bridge arm switch of the second bridge arm connected to the p-phase armature winding is a faulty switch pair; when the current residual When the error range exceeds 0 and is greater than 0, it is determined that the switch tube pair formed by the lower bridge arm switch tube of the first bridge arm and the upper bridge arm switch tube of the second bridge arm connected to the p-phase armature winding is a faulty switch tube pair.

[0155] Step 4, when the motor electrical angle θ is within the conduction electrical angle interval of the non-fault switch pair of the p-phase armature winding, keep the two switch tubes of the non-fault switch pair connected to the p-phase armature winding turned off, control the on-off relationship of the two switch tubes in the faulty switch pair to utilize the motor back electromotive force to inject a diagnostic pulse, and determine the switch tube with an open circuit fault in the faulty switch pair based on the response current of the p-phase armature winding after the diagnostic pulse is injected.

[0156] Since the same switch tube in the same switch tube pair has the same current residual characteristics when an open circuit fault occurs, it is necessary to further accurately locate the faulty switch tube. Therefore, the present application uses the method of diagnostic pulse injection using the motor back electromotive force to locate the specific faulty switch tube. When one of the switch tubes in the switch tube pair connected to the p-phase armature winding in the forward current loop fails, the power supply can no longer provide forward energy to the faulty phase, so the phase current lacks a positive half cycle. However, thanks to the strong fault-tolerant operation capability of the open-winding SDSEM drive system, the other two non-fault phases can still maintain motor operation, and the faulty phase is converted from electric mode to power generation mode.

[0157] In one electrical angle cycle, the conduction electrical angle interval of the faulty switch pair and the non-faulty switch pair of the faulty phase each occupies half of the electrical angle cycle, and the motor back EMF generated by the conduction of the faulty switch pair is opposite to the motor back EMF generated by the conduction of the non-faulty switch pair. In addition, since the switch tube is anti-parallel with the freewheeling diode, the motor back EMF generated by the non-faulty switch pair in the conduction electrical angle interval can be used to inject diagnostic pulses through the loop formed by the anti-parallel freewheeling diode of the non-faulty switch tube and the faulty switch tube. In the case where the faulty switch tube pair is in a forward current loop, it is only necessary to provide a forward loop that satisfies the operation of any one of the switch tubes alone, and the motor back EMF generated by the non-faulty switch tube pair in the conduction electrical angle interval can be used to inject diagnostic pulses, and then observe whether a forward response current is generated, so as to locate the faulty switch tube. On the contrary, in the case where the faulty switch tube pair is in a negative current loop, it is only necessary to provide a negative loop that satisfies the operation of any one of the switch tubes alone. The motor back electromotive force generated by the non-faulty switch tube pair within the conduction electrical angle range can be used to inject diagnostic pulses, and then observe whether a negative response current is generated to locate the faulty switch tube.

[0158] In one embodiment, determining the switch tube having an open circuit fault in the faulty switch tube pair according to the response current of the p-phase armature winding after the diagnostic pulse is injected includes:

[0159] The two switch tubes in the fault switch tube pair connected to the p-phase armature winding are controlled to conduct one tube at a time. When the response current of the p-phase armature winding in the process of single tube conduction reaches the threshold value i thWhen the faulty switch tube is detected, it is determined that the switched-off switch tube has an open circuit fault and the switched-on switch tube is operating normally;

[0160] When the response current of the p-phase armature winding during the single-tube conduction process does not reach the threshold value i th When , it is determined that both switch tubes in the faulty switch tube pair have open circuit faults.

[0161] Taking phase A as an example, when T a1 When an open circuit fault occurs, the forward current flows along the path Figure 5 As shown, due to T a3 The anti-parallel freewheeling diode D2 can be connected with T a2 To form a forward loop, you only need to open T a2 The diagnostic pulse self-injection can be realized, thereby generating a positive response current. a2 When an open circuit fault occurs, the forward current flows along the path Figure 6 As shown, at this time, you only need to open T a1 The diagnostic pulse self-injection can be realized, thereby generating a positive response current. a1 and T a2 When an open circuit fault occurs, it cannot provide the T a1 or T a2 For the forward loop operating alone, there is no response current after the diagnostic pulse is injected.

[0162] In order to prevent the non-faulty switch from a3 and T a4 The negative current generated by the conduction voltage source affects the flow of the positive current generated by the reverse electromotive force. a1 and T a2 After the faulty switch pair is found, the non-faulty switch pair is immediately turned off T a3 and T a4 In the non-faulty switch pair T a3 and T a4 Within the conduction electrical angle range of T a1 and T a2 The single transistors are turned on in sequence to inject the diagnostic pulse. In one embodiment, the fault switch pair T a1 and T a2 The specific fault location process is as follows:

[0163] (1) When the motor electrical angle θ is in the range (0, θ1), only T is turned on. a2 If the response current reaches the threshold value i th When T a2 And judged as the faulty switch pair T a1 and T a2 Middle upper bridge arm switch tube T a1An open circuit fault occurs. The back EMF and response current of the diagnostic pulse injection process are as follows Figure 7 shown.

[0164] (2) When the motor electrical angle θ is in the interval (θ1, θ2), only T is turned on. a1 If the response current reaches the threshold value i th When T a1 And judged as the faulty switch pair T a1 and T a2 Middle and lower bridge arm switch tube T a2 An open circuit fault occurs. The back EMF and response current of the diagnostic pulse injection process are as follows Figure 8 shown.

[0165] (3) When the motor electrical angle θ = θ2, T a1 and T a2 All are turned off. If the response current is detected to be less than the threshold value i in the interval (0,θ2) th , it is determined that the faulty switch pair T a1 and T a2 Medium T a1 and T a2 The double tube has an open circuit fault. The back electromotive force and response current of the diagnostic pulse injection process are as follows Fig. 9 shown.

[0166] It should be noted that it is OK to open the upper arm switch tube or the lower arm switch tube of the faulty switch tube first, and it is only necessary to ensure that the two switch tubes are turned on separately in sequence. In this example, the diagnostic pulse uses the negative back electromotive force, and the motor electrical angle θ is in the non-fault switch tube pair T a3 and T a4 In the conduction angle interval (0,π), θ1 and θ2 must satisfy (0<θ1<θ2≤π). Similarly, when the switch tube is on T a3 and T a4 When an open circuit fault occurs, the forward reverse electromotive force is used to inject the diagnostic pulse. At this time, the motor electrical angle θ is in the non-fault switch pair T a1 and T a2 Within the conduction electrical angle interval (π, 2π), θ1 and θ2 must satisfy (π<θ1<θ2≤2π). The values ​​of θ1 and θ2 can be determined based on the minimum diagnostic pulse injection interval required for the generated response current to reach the threshold.

[0167] The system control process of the open-winding SDSEM drive system switch tube open circuit fault diagnosis method proposed in this application is as follows: Fig.10As shown. The open-winding SDSEM is driven by a speed and current dual closed-loop vector control strategy, and the excitation converter is controlled by an asymmetric half-bridge. The hybrid logic dynamic model-based fault detection unit collects the phase current and the main power converter switch tube drive signal and uses the hybrid logic dynamic model for real-time observation to detect the faulty switch tube and pass the detection result to the diagnostic pulse self-injection fault location unit. The diagnostic pulse self-injection fault location unit controls the diagnostic pulse injection according to the position information to locate the faulty switch tube and pass the location result to the SVPWM modulation unit so as to replace the control strategy in time to deal with the fault situation, avoid affecting the motor operation, and prevent damage to the motor.

[0168] The above 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 changes directly derived or associated 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 protection scope of the present application.

Claims

1. A method for diagnosing open-circuit faults of switch tubes in an open-winding SDSEM drive system, characterized in that: The main power converter in the open-winding SDSEM drive system includes two three-bridge-arm inverters, one end of the three-phase armature windings A, B, and C of the open-winding SDSEM is respectively connected to the midpoint of the three bridge arms in one three-bridge-arm inverter, and the other end of the three-phase armature windings A, B, and C is respectively connected to the midpoint of the three bridge arms in another three-bridge-arm inverter. The open-winding SDSEM drive system switch tube open circuit fault diagnosis method includes: Based on the voltage equation of the sinusoidal electrically excited doubly salient motor, a hybrid logic dynamic model of the p-phase armature winding of the open winding SDSEM is constructed. The hybrid logic dynamic model represents the current observation value of the p-phase armature winding. The relationship between the switch states of the two bridge arms connected to the p-phase armature winding; where p = a, b, c represents the A, B, and C-phase armature windings respectively; Based on the hybrid logic dynamic model of the p-phase armature winding, the observed current of the p-phase armature winding is obtained by real-time observation. And determine the phase current i of the p-phase armature winding p Its observed current The current residual When the residual current of the p-phase armature winding If the error is within 0, it is determined that the switch tubes in the two bridge arms connected to the p-phase armature winding are working properly. Otherwise, according to the current residual The positive or negative value of determines the faulty switch tube pair connected to the p-phase armature winding, the faulty switch tube pair is a switch tube pair including a switch tube open circuit fault among the two switch tube pairs connected to the p-phase armature winding, each switch tube pair includes an upper bridge arm switch tube in one bridge arm connected to the p-phase armature winding and a lower bridge arm switch tube in another bridge arm; When the motor electrical angle θ is within the conduction electrical angle range of the non-fault switch pair of the p-phase armature winding, the two switch tubes of the non-fault switch pair connected to the p-phase armature winding are kept turned off, and the on-off relationship of the two switch tubes in the faulty switch pair is controlled to utilize the motor back electromotive force to inject a diagnostic pulse, and the switch tube with an open circuit fault in the faulty switch pair is determined based on the response current of the p-phase armature winding after the diagnostic pulse is injected.

2. The method for diagnosing a switch tube open circuit fault according to claim 1, characterized in that: The hybrid logic dynamic model of the three-phase armature winding of the open-winding SDSEM is: in, Observed current of three-phase armature winding Observe the differential of the current i f is the field winding current, R p is the resistance of the p-phase armature winding, L p is the self-inductance of the p-phase armature winding, L pf is the mutual inductance between the p-phase armature winding and the field winding; δ = [δ a ,δ b ,δ c ] T It is the discrete input quantity under the motor electrical angle θ when the open winding SDSEM drive system is working normally. δ ip It is the phase current direction of the p-phase armature winding at the real-time motor electrical angle θ when the open-winding SDSEM drive system is working normally. Indicates the ip Negate; S p1 It is the upper bridge arm switch tube T of the first bridge arm connected to the p-phase armature winding p1 The drive signal at the motor electrical angle θ, S p2 It is the lower bridge arm switch tube T of the second bridge arm connected to the p-phase armature winding p2 The drive signal at the motor electrical angle θ, S p3 It is the lower bridge arm switch tube T of the first bridge arm connected to the p-phase armature winding p3 The drive signal at the motor electrical angle θ, S p4 It is the upper bridge arm switch tube T of the second bridge arm connected to the p-phase armature winding p4 The driving signal at the motor electrical angle θ, the phase current i of the p-phase armature winding p The current flowing from the midpoint of the first bridge arm to the midpoint of the second bridge arm is regarded as the positive direction of the current, U dc is the DC bus voltage; for any parameter j∈[1,4], the drive signal S pj =1 means the switch is on, the drive signal S pj =0 means the switch is turned off. Indicates the driving signal S pj Negate, [] T Represents matrix transpose.

3. The method for diagnosing open-circuit fault of a switch tube in an open-winding SDSEM drive system according to claim 2, characterized in that: According to the current residual The positive or negative value of determines the fault switch tube pair connected to the p-phase armature winding, including: When the current residual When the error range exceeds 0 and is less than 0, it is determined that the switch tube pair consisting of the upper bridge arm switch tube of the first bridge arm and the lower bridge arm switch tube of the second bridge arm connected to the p-phase armature winding is a faulty switch tube pair; When the current residual When the error range exceeds 0 and is greater than 0, it is determined that the switch tube pair formed by the lower bridge arm switch tube of the first bridge arm and the upper bridge arm switch tube of the second bridge arm connected to the p-phase armature winding is a faulty switch tube pair.

4. The method for diagnosing open-circuit fault of a switch tube in an open-winding SDSEM drive system according to claim 1, characterized in that: The method of determining the switch tube having an open circuit fault in the faulty switch tube pair according to the response current of the p-phase armature winding after the diagnostic pulse is injected comprises: The two switch tubes in the fault switch tube pair connected to the p-phase armature winding are controlled to conduct one tube at a time. When the response current of the p-phase armature winding in the process of single tube conduction reaches the threshold value i th When the faulty switch tube is detected, it is determined that the switched-off switch tube has an open circuit fault and the switched-on switch tube is operating normally; When the response current of the p-phase armature winding during the single-tube conduction process does not reach the threshold value i th When , it is determined that both switch tubes in the faulty switch tube pair have open circuit faults.

5. The method for diagnosing open-circuit fault of a switch tube in an open-winding SDSEM drive system according to claim 3, characterized in that: The hybrid logic dynamic model of the three-phase armature winding is constructed by: The voltage equation for determining the sinusoidal electrically excited double-pole motor is: Wherein, d is a differential operator; solving the voltage equation of the sinusoidal electrically excited double-pole motor to obtain the current equation of the sinusoidal electrically excited double-pole motor is: According to the working principle of the main power converter in the open-winding SDSEM drive system, the p-phase terminal voltage U is determined when the open-winding SDSEM drive system is working normally. p1p2 Substituting the expression into the current equation of the sinusoidal electrically excited doubly salient motor, the hybrid logic dynamic model of the three-phase armature winding is obtained, and the discrete input quantity δ=[δ a ,δ b ,δ c ] T =[U a1a2 ,U b1b2 ,U c1c2 ] T and:

6. The method for diagnosing open-circuit fault of a switch tube in an open-winding SDSEM drive system according to claim 5, characterized in that: The open-winding SDSEM drive system switch tube open circuit fault diagnosis method further includes: According to the working principle of the main power converter in the open-winding SDSEM drive system, the p-phase fault terminal voltage U of the open-winding SDSEM drive system under different switch tube open-circuit fault conditions is determined. p ' 1p2 Substitute the expression into the current equation of the sinusoidal electrically excited doubly salient pole motor to obtain the current state equation of the three-phase armature winding under the corresponding switch tube open circuit fault condition: δ′=[δ a ′,δ b ′,δ c ′] T =[U a ' 1a2 ,U b ' 1b2 ,U c ' 1c2 ] T It is the discrete input quantity of the open-winding SDSEM drive system with the motor electrical angle θ under different switch tube open-circuit fault conditions; The hybrid logic dynamic model of the three-phase armature winding is subtracted from the current state equation of the three-phase armature winding under the corresponding switch tube open circuit fault condition to obtain the expression of the current residual under the corresponding switch tube open circuit fault condition: And determine the positive and negative value of the current residual, where: is the current residual of the p-phase armature winding.

7. The method for diagnosing open-circuit fault of a switch tube in an open-winding SDSEM drive system according to claim 6, characterized in that: Determine the p-phase fault terminal voltage U when different switch tube open circuit faults occur in the first bridge arm and the second bridge arm connected to the p-phase armature winding p ' 1p2 The expressions include: Determine the expression of the current residual under different switch tube open circuit fault conditions and determine the positive and negative values ​​of the current residual, including: Determine the upper bridge arm switch tube T of the first bridge arm connected to the p-phase armature winding p1 When a single tube fails, the current residual of the p-phase armature winding is expressed as And solve it to get Sure Determine the lower bridge arm switch tube T of the second bridge arm connected to the p-phase armature winding p2 When a single tube fails, the current residual of the p-phase armature winding is expressed as And solve it to get Sure Determine the upper bridge arm switch tube T of the first bridge arm connected to the p-phase armature winding p1 And the lower bridge arm switch tube T of the second bridge arm p2 When the double-tube open circuit fault occurs, the expression of the current residual of the p-phase armature winding is: And solve it to get Sure Determine the lower bridge arm switch tube T of the first bridge arm connected to the p-phase armature winding p3 When a single tube fails, the current residual of the p-phase armature winding is expressed as And solve it to get Sure Determine the upper bridge arm switch tube T of the second bridge arm connected to the p-phase armature winding p4 When a single tube fails, the current residual of the p-phase armature winding is expressed as And solve it to get Sure Determine the lower bridge arm switch tube T of the first bridge arm connected to the p-phase armature winding p3 And the upper bridge arm switch tube T of the second bridge arm p4 When the double-tube open circuit fault occurs, the expression of the current residual of the p-phase armature winding is: And solve it to get Sure

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