A Fault Diagnosis Method for Open - Circuit Fault of Switching Devices in an Open - Winding SDSEM Drive System

Abstract

This application discloses a method for diagnosing open-circuit faults of switch tubes in an open-winding SDSEM drive system, relating to the field of aviation motor control. The method comprises: constructing a hybrid logic dynamic model of the p-phase armature winding current of the open-winding SDSEM based on the voltage equation of a sinusoidal, electrically excited, doubly salient-pole motor; observing the observed current of the p-phase armature winding in real time and determining the phase current of the p-phase armature winding and the current residual of the observed current; determining the faulty switch tube pair connected to the p-phase armature winding based on the positive or negative value of the current residual; controlling the on-off relationship of the two switch tubes in the faulty switch tube pair to inject a diagnostic pulse using the motor's back electromotive force, and determining the switch tube with the open-circuit fault based on the response current of the p-phase armature winding after the diagnostic pulse injection. This application utilizes an open-circuit fault diagnosis method that combines a hybrid logic dynamic model with diagnostic pulse self-injection to achieve single-tube and dual-tube fault location while significantly improving diagnostic speed.

Description

Technical Field

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

[0002] The 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 the event of a fault. In addition, the torque ripple is smaller than that of the traditional doubly salient electromagnetic machine. It has broad application prospects in high-demand fields such as aviation, new energy power generation, and electric vehicles.

[0003] To ensure stable performance of sinusoidal, electrically excited, doubly salient-pole motors, the operational performance and reliability of the motor drive system are crucial. Compared to single-inverter motor drive systems, dual-inverter open-winding motor drive systems offer a wider speed range and greater fault tolerance. However, since the number of switches doubles, the probability of failure also increases. In particular, open-circuit failures of switches can severely impact motor system performance and even damage the system.

[0004] Traditional fault diagnosis methods such as unipolar disturbance or active change of the fault phase arm operation mode can only perform single-tube open-circuit fault diagnosis, and the positioning accuracy is not high. In addition, there is currently no method for diagnosing the open-circuit fault of the switch tube in the open-winding motor drive system of the sinusoidal electromagnetic double-pole motor. Summary of the Invention

[0005] In response to the above-mentioned 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-leg inverters. One end of the A, B, and C three-phase armature windings of the open-winding SDSEM is connected to the midpoint of the three bridge arms of one three-leg inverter, and the other end of the A, B, and C three-phase armature windings is connected to the midpoint of the three bridge arms of the other three-leg 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-phase, B-phase, 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 and its observed current The current residual

[0010] When the residual current of the p-phase armature winding When 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 the other 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 inject a diagnostic pulse using the motor back electromotive force, 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 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 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 driving 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 driving 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 driving 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 considered to be in the positive direction, U dc is the DC bus voltage; for any parameter j∈[1,4], the drive signal S pj =1 means the switch is on, and the driving 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 of 0 is exceeded and is greater than 0, it is determined that the switch tube pair consisting of 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 based on the response current of the p-phase armature winding after the diagnostic pulse is injected, including:

[0019] The two switching tubes in the fault switching 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 does not reach the threshold value i during the single-tube conduction process 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 doubly salient motor is:

[0023]

[0024] Where d is the differential operator. Solving the voltage equation of the sinusoidal electrically excited doubly salient motor yields the current equation of the sinusoidal electrically excited doubly salient 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 The expression is substituted into the current equation of the sinusoidal electric excitation doubly salient pole motor to obtain the hybrid logic dynamic model of the three-phase armature winding, 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. p1p2Substituting the expression into the current equation of the sinusoidal electrically excited doubly salient motor, the current state equation of the three-phase armature winding under the corresponding switch open circuit fault is obtained. 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 under different switch tube open-circuit fault conditions along with the motor electrical angle θ;

[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] This application proposes a method for diagnosing open-circuit faults in switch tubes in an open-winding SDSEM drive system. By constructing a hybrid logic dynamic model to observe motor phase currents in real time, the method analyzes the switching states of various open-circuit faults for the unique topology of the open-winding SDSEM drive system and derives the current residual between the motor phase current and the observed current. The faulty switch tube pair is then located by detecting the positive or negative value of the current residual in real time. Because the motor phase currents are observed in real time during operation of the open-winding SDSEM drive system, the faulty switch tube pair can be located at the moment an open-circuit fault occurs. This significantly improves the speed of fault detection compared to existing methods, effectively ensuring the safety and stability of 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 an open circuit fault. It does not rely on motor parameters and the assistance of other additional hardware and equipment. It can accurately locate the faulty switch tube by only using the motor back electromotive force of the open-winding SDSEM drive system itself, and there is no need to determine the diagnostic pulse width. It is highly reliable and easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is the topological structure diagram of the 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 diagram showing the conduction logic and phase current waveforms of a sinusoidal electrically excited double-pole motor according to an embodiment.

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

[0047] Figure 5 It's T P1 The current flow path after the diagnostic pulse is injected during an open circuit fault.

[0048] Figure 6 It's T P2 The current flow path after the diagnostic pulse is injected during an open circuit fault.

[0049] Figure 7 It's T P1 Motor back EMF and response current after diagnostic pulse injection during open circuit fault.

[0050] Figure 8 It's T P2 Motor back EMF and response current after diagnostic pulse injection during open circuit fault.

[0051] Figure 9 It's T P1 and T P2 Motor back EMF and response current after diagnostic pulse injection during open circuit fault.

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

[0053] The specific implementation of this application will be further described below with reference to 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 this application opens the neutral point of the three-phase armature winding. The specific structure is as follows: Figure 1As shown, the main power converter in the open-winding SDSEM drive system consists of two three-leg inverters. One end of the three-phase armature windings (A, B, and C) of the open-winding SDSEM is connected to the midpoints of the three arms of one three-leg inverter, while the other end of the three-phase armature windings (A, B, and C) is connected to the midpoints of the three arms of the other three-leg inverter. Four switching transistors are connected to each armature winding at both ends, each connected in antiparallel with a freewheeling diode. Compared to the single-inverter structure of traditional sinusoidal, electrically excited, doubly salient motor drive systems, the open-winding SDSEM drive system offers improved fault tolerance and flexibility. If a switching transistor in one inverter fails, the lower legs of that inverter can be switched on while the other inverter remains operational. The dual-inverter system then operates as a single inverter, achieving constant torque and half-speed operation, thus ensuring safe system operation.

[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 specific steps in the flowchart are as follows:

[0056] Step 1: Using hybrid system theory and the voltage equation of the sinusoidal 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-phase, B-phase, 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 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 ipThe 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 means 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 conductive; 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 driving 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 driving 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 driving 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 considered to be in the positive direction, U dc is the DC bus voltage; for any parameter j∈[1,4], the drive signal S pj =1 means the switch is on, and the driving 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 operating normally. p1p2 The expression is substituted into the current equation of the sinusoidal electrically excited doubly salient motor to obtain the hybrid logic dynamic model of the three-phase armature winding.

[0068] First, the operating modes of the main power converter and motor of the open-winding SDSEM drive system are analyzed to establish the relationship between the terminal voltage, the inverter switch state, and the phase current flow. The conduction logic and phase current waveform of the sinusoidal electromagnetic doubly salient motor under vector control are shown in the figure. 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 in different states are analyzed.

[0069] The p-phase terminal voltage of the open-winding SDSEM drive system when it is operating 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 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 means 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 conductive, 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 under the action of the drive signal when it is working normally is expressed as:

[0080]

[0081] Phase current i during normal operation of the open-winding SDSEM drive system p Equal to the observed current Substituting formula (4) into formula (3), 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 and 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 is When 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 pair connected to the p-phase armature winding. The faulty switch pair is the switch pair with an open-circuit fault in the two switch pairs connected to the p-phase armature winding. Each switch pair includes an upper-arm switch in one bridge arm connected to the p-phase armature winding and a lower-arm switch in the other bridge arm. The switch 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 or 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 when the open-winding SDSEM drive system has an open-circuit fault 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 when an open-circuit fault occurs in the open-winding SDSEM drive system under the action of the drive signal is expressed as:

[0120]

[0121] Substituting formula (6) into the current equation of the sinusoidal electromagnetic doubly salient 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 along 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 value 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] Under normal circumstances, when t=0, set δ′ is equal to δ, and the current residual is also equal to zero; when t>0, due to T p1 When a single tube open circuit fault occurs 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 a single tube open circuit fault occurs

[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 open circuit fault occurs 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 a single tube open circuit fault occurs

[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 during double-tube open circuit fault

[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 open circuit fault occurs 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 a single tube open circuit fault occurs

[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 open circuit fault occurs 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 a single tube open circuit fault occurs

[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 during double-tube open circuit fault

[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 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 of 0 is exceeded and is greater than 0, it is determined that the switch tube pair consisting of 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 range 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 inject a diagnostic pulse using the motor back electromotive force, 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 current residual characteristics exist when the switch tubes in the same switch tube pair have an open circuit fault, 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 a switch tube 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 loses the 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 now converted from electric mode to power generation mode.

[0157] Within one electrical angle cycle, the conduction electrical angle intervals of the faulty switching tube pair and the non-faulty switching tube pair of the faulty phase each occupy half an electrical angle cycle, and the motor back EMF generated by the conduction of the faulty switching tube pair is opposite in direction to the motor back EMF generated by the conduction of the non-faulty switching tube pair. Moreover, since the switching tubes are anti-parallel with the freewheeling diode, the motor back EMF generated by the non-faulty switching tube pair within the conduction electrical angle interval can be used to inject diagnostic pulses through the circuit formed by the anti-parallel freewheeling diode of the non-faulty switching tube and the faulty switching tube. For the case where the faulty switching 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 switching tubes alone. The motor back EMF generated by the non-faulty switching tube pair within the conduction electrical angle interval can be used to inject diagnostic pulses, and then observe whether a forward response current is generated to locate the faulty switching tube. On the contrary, in the case where the faulty switch 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 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 based on the response current of the p-phase armature winding after the diagnostic pulse is injected includes:

[0159] The two switching tubes in the fault switching 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 does not reach the threshold value i during the single-tube conduction process 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 flow path is as follows 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. Similarly, when T a2 When an open circuit fault occurs, the forward current flow path is as follows Figure 6 As shown, at this time, you only need to open T a1 The diagnostic pulse can be injected by itself, thus generating a positive response current. a1 and T a2 When an open circuit fault occurs, it cannot provide the a1 or T a2 In 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 forward current generated by the back electromotive force. When T a1 and T a2 After the faulty switch pair is detected, the non-faulty switch pair T is immediately turned off. 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 In one embodiment, the fault switch pair T a1 and T a2 The specific fault locating 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 determine that the faulty switch pair T a1 and T a2 Middle upper arm switch tube T a1An open circuit fault occurs. The back electromotive force 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 determine that 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 electromotive force 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 If the response current does not reach the threshold value i in the interval (0,θ2) th , it is determined that the faulty switch pair T a1 and T a2 Middle T a1 and T a2 The double tubes have an open circuit fault. The back electromotive force and response current of the diagnostic pulse injection process are as follows Figure 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, as long as the two switches 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-faulty switch tube pair T a3 and T a4 In the conduction angle range (0,π), θ1 and θ2 must satisfy (0<θ1<θ2≤π). Similarly, when the switch tube is connected to T a3 and T a4 When an open circuit fault occurs, the forward back electromotive force is used to inject a diagnostic pulse. At this time, the motor electrical angle θ is in the non-faulty switch pair T a1 and T a2 Within the conduction electrical angle range (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-circuit fault diagnosis method of the open-winding SDSEM drive system proposed in this application is as follows: Figure 10As shown in the figure, the open-winding SDSEM is driven using a dual closed-loop vector control strategy for speed and current, and the excitation converter is controlled using an asymmetric half-bridge. A hybrid logic dynamic model-based fault detection unit collects phase currents and the main power converter switch drive signals and uses the hybrid logic dynamic model for real-time observation to detect faulty switches. The detection results are then transmitted to a diagnostic pulse self-injection fault location unit. This unit controls the injection of diagnostic pulses based on position information to locate the faulty switch and transmits the location results to the SVPWM modulation unit, enabling timely control strategy changes to address the fault, preventing impacts on motor operation and damage to the motor.

[0168] 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 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-leg 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-leg 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-leg 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 observed current 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-phase, B-phase, 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 and its observed current The current residual When the residual current of the p-phase armature winding When 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 the other 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 inject a diagnostic pulse using the motor back electromotive force, 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, wherein: 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 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 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 driving 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 driving 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 driving 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 considered to be in the positive direction, U dc is the DC bus voltage; for any parameter j∈[1,4], the drive signal S pj =1 means the switch is on, and the driving 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 an 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 of 0 is exceeded and is greater than 0, it is determined that the switch tube pair consisting of 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 an 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 switching tubes in the fault switching 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 does not reach the threshold value i during the single-tube conduction process 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 faults of switch tubes in an open-winding SDSEM drive system according to claim 3, characterized in that: Constructing a hybrid logic dynamic model of a three-phase armature winding includes: The voltage equation for determining the sinusoidal electrically excited doubly salient motor is: Wherein, d is a differential operator; solving the voltage equation of the sinusoidal electrically excited doubly salient pole motor to obtain the current equation of the sinusoidal electrically excited doubly salient 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 The expression is substituted into the current equation of the sinusoidal electric excitation doubly salient pole motor to obtain the hybrid logic dynamic model of the three-phase armature winding, 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 an 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 is determined under different switch tube open circuit fault conditions. p ' 1p2 Substituting the expression into the current equation of the sinusoidal electrically excited doubly salient motor, the current state equation of the three-phase armature winding under the condition of the corresponding switch tube open circuit fault is obtained. 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 under different switch tube open-circuit fault conditions along with the motor electrical angle θ; 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 an 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 p1p2 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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