Current source inverter short-circuit fault diagnosis method based on phase current and average absolute value hybrid error thereof

Abstract

The invention relates to a current source inverter short circuit fault diagnosis method based on phase current and average absolute value mixed error thereof. The invention relates to the technical field of motor control, and the method comprises the steps: collecting the A, B and C three-phase current of a permanent magnet synchronous motor in real time in a process that a current source inverter drives the permanent magnet synchronous motor to operate, and carrying out the filtering and noise reduction of the A, B and C three-phase current; a Park vector module value is obtained through Park transformation, and the three-phase current is divided by the Park vector module value to carry out normalization processing on the phase current; generating a hybrid diagnosis variable and an auxiliary diagnosis variable based on the reference current and actual current error and the average absolute value and average value error of the normalized current; and in combination with a preset threshold value and variable combinational logic, precise positioning of single-tube short circuit, same-side out-of-phase double-tube short circuit and different-side out-of-phase double-tube short circuit is realized.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of motor control and is a current source inverter short-circuit fault diagnosis method based on phase current and average absolute value hybrid error. BACKGROUND

[0002] With the wide deployment of current source inverters in various industrial application scenarios, the safety and reliability of the current source inverters have attracted increasing attention, and the short-circuit fault diagnosis, which has a significant impact on motor systems, is particularly crucial. The operating environment of the inverter is usually complex, and long-term operation may be affected by overcurrent, overvoltage, short circuit, electromagnetic interference and the like, resulting in system failure. The CSI uses a direct current source as input, usually uses a large inductance for energy storage, and adjusts the output power through current control, and for the CSI, the short-circuit fault has a great impact, mainly because the inductive energy storage feature causes a short-circuit current impact, the direct current side of the CSI is a large inductance, when a short circuit occurs, the inductive energy storage will be released through a low-impedance path, causing a high-amplitude impact current, which may burn the device or cause more serious system damage. Therefore, efficient and accurate fault diagnosis of the current source inverter is crucial, which can reduce equipment damage, improve operating efficiency and reduce maintenance costs. SUMMARY

[0003] The current source inverter short-circuit fault diagnosis method based on phase current and average absolute value hybrid error of the application normalizes the three-phase current by dividing the three-phase current by the Park vector modulus value, generates hybrid diagnosis variables and auxiliary variables based on the reference current and actual current error and the average absolute value and average value error of the normalized current, and realizes accurate positioning of single-pipe short circuit, same-side different-phase double-pipe short circuit and different-side different-phase double-pipe short circuit by combining a preset threshold value and variable combination logic. The application does not require an additional voltage sensor, and significantly improves the robustness and multi-type fault compatibility of fault diagnosis.

[0004] The application provides the following technical solutions: A current source inverter driving permanent magnet synchronous motor system based on phase current and average absolute value hybrid error, characterized by comprising: a voltage source, a DC-DC converter and an inductor L dc a switch tube S1, a switch tube S2, a switch tube S3, a switch tube S4, a switch tube S5, a switch tube S6, a diode D1, a diode D2, a diode D3, a diode D4, a diode D5, a diode D6 and a capacitor C f and a permanent magnet synchronous motor PMSM The voltage source is connected to the DC-DC converter, one end of the DC-DC converter is connected to the inductor L dc one end of the inductorL dc The other end of the switch tube S1, the switch tube S3 and the switch tube S5 is connected, the other end of the switch tube S1 is connected to one end of the diode D1, the other end of the switch tube S3 is connected to one end of the diode D3, and the other end of the switch tube S5 is connected to one end of the diode D5; The other end of the diode D1 is connected to one end of the switch tube S4, the other end of the diode D3 is connected to one end of the switch tube S6, and the other end of the diode D5 is connected to one end of the switch tube S2; the switch tube S4, the switch tube S6 and the switch tube S2 are connected to the ABC three-phase of the permanent magnet synchronous motor PMSM, and the connection is connected to the capacitor C f ; The other end of the switch tube S4 is connected to one end of the diode D4, the other end of the switch tube S6 is connected to one end of the diode D6, and the other end of the switch tube S2 is connected to one end of the diode D2. The other end of the DC-DC converter is connected to the other end of the diode D4, the diode D6 and the diode D2.

[0005] A current source inverter short circuit fault diagnosis method based on phase current and average absolute value mixed error, the method is based on a current source inverter driving permanent magnet synchronous motor system based on phase current and average absolute value mixed error, the method comprises the following steps: Step 1: real-time acquisition of ABC three-phase current of permanent magnet synchronous motor in the process of current source inverter driving permanent magnet synchronous motor i a , i b , i c , and filtering and denoising processing is carried out; Step 2: calculate i d and i q , and then obtain the park vector module value, and normalize the three-phase current by dividing the park vector module value; Step 3: based on the reference current and the actual current error and the average absolute value and average value error of the normalized current, generate mixed diagnosis variable e and auxiliary diagnosis variable M ; Step 4: combining the preset threshold value and variable combination logic, realizing the accurate positioning of single tube short circuit, same side and different phase double tube short circuit and different side and different phase double tube short circuit.

[0006] Preferably, the step 2 is performed by dividing the motor phase current by the park vector module, and the normalized motor phase current obtained is given by the following formula:

[0007]

[0008] The auxiliary diagnosis variable in step 3 is preferably M The reaction is the average feature of each phase current cycle when the tube has a short circuit fault, and the variable e, M The formula is as follows:

[0009]

[0010] Wherein, α, β are weight coefficients, α = 0.3, β = 0.7 by default, I is the reference current, I is the actual current, The average absolute value of the motor phase current is represented; The average value of the phase current cycle is represented; L represents the average value of the phase current cycle is negative; H represents the average value of the phase current cycle is positive.

[0011] Preferably, M n The reaction is the average feature of each phase current cycle when the tube has a short circuit fault, wherein L represents the average value of the phase current cycle is negative, and H represents the average value of the phase current cycle is positive.

[0012] Preferably, S is used to distinguish the same side and different phase double tube fault S = 3, and the different side and different phase double tube fault S = 2; the auxiliary variable E n N in the auxiliary variable represents that the tube is in a normal working state; P represents a single tube fault; Q represents a same side and different phase double tube fault; D represents a different side and different phase double tube fault, k 1, k 2 is a determined threshold value; E n Only a fault in a certain phase can be determined, and accurate positioning to the upper bridge arm or the lower bridge arm cannot be determined, and finally the auxiliary variable M n is needed to locate the specific position of the abnormal tube.

[0013] Preferably, when the inverter appears the following situations: e a k 1, e b k 1, e c k 1; ( M a ,​​​M b , M c )=(1,-1,-1), by e a < k 1 knows that the inverter occurs single tube fault, and the fault phase is A phase, and according to M a , M b , M c )=(1,-1,-1) judges that A phase is H, which is the upper tube short circuit, so the tube that appears short circuit fault is T1.

[0014] Preferably, when the inverter appears the following situations: e a > k 2, e b > k 2, e c < k 2; ( M a , M b , M c )=(1,1,-1); S=3, by e a > k 2, e b > k 2, e c < k 2, S=3 knows E n =Q, that is, in the same side and different phase double tube fault, k 2 e n The corresponding two phases are the fault phases, according to M a , M b , M c )=(1,1,-1) judges that A and B phases are H, which is the upper tube abnormal, so the tube that appears short circuit fault is T1 and T3.

[0015] A computer readable storage medium, having stored thereon a computer program, which is executed by a processor to implement a current source inverter short circuit fault diagnosis method based on phase current and its average absolute value hybrid error.

[0016] A computer device comprises a memory and a processor, the memory stores a computer program, and the processor implements a current source inverter short-circuit fault diagnosis method based on phase current and average absolute value mixed error of the phase current when executing the computer program.

[0017] The present application has the following beneficial effects: The present application is a current source inverter short-circuit fault diagnosis method based on phase current and average absolute value mixed error, which normalizes three-phase current by dividing by the Parker vector module value, generates mixed diagnosis variables and auxiliary diagnosis variables based on reference current and actual current error and average absolute value and average value error of the normalized current, and realizes accurate positioning of single tube short circuit, same side and different phase double tube short circuit and different side and different phase double tube short circuit by combining preset threshold and variable combination logic. The present application combines reference current error and normalized current error, enhances load independence and fault sensitivity, solves the problem of single error quantity being sensitive to transient load fluctuation, does not require additional voltage sensors, and significantly improves the robustness and multi-type fault compatibility of fault diagnosis. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the specific embodiments or prior art of the present application, the drawings needed in the specific embodiments or prior art description will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without creative labor.

[0019] Figure 1 A structure diagram of a permanent magnet synchronous motor system powered by a current source inverter of the present application is shown; Figure 2 A flow chart of the present application is shown; Figure 3 A fault type phase current characteristic table of the present application is shown. DETAILED DESCRIPTION

[0020] The technical solutions of the present application will be described in detail below with reference to the drawings. Obviously, the described embodiments are some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0021] The present application is described in detail below in combination with specific embodiments. Embodiment one: According to Figures 1 to 3The application is a current source inverter short-circuit fault diagnosis method based on phase current and mixed error of average absolute value thereof.

[0023] The application provides a current source inverter drive permanent magnet synchronous motor system based on phase current and mixed error of average absolute value thereof. Voltage source, DC-DC converter, inductor L dc Switching tube S1, switching tube S2, switching tube S3, switching tube S4, switching tube S5, switching tube S6, diode D1, diode D2, diode D3, diode D4, diode D5, diode D6, capacitor C f and permanent magnet synchronous motor PMSM The voltage source is connected with the DC-DC converter at both sides, one end of the DC-DC converter is connected with the inductor L dc The other end of the inductor L dc is connected with one end of switching tube S1, switching tube S3 and switching tube S5, the other end of switching tube S1 is connected with one end of diode D1, the other end of switching tube S3 is connected with one end of diode D3, and the other end of switching tube S5 is connected with one end of diode D5. The other end of diode D1 is connected with one end of switching tube S4, the other end of diode D3 is connected with one end of switching tube S6, and the other end of diode D5 is connected with one end of switching tube S2; switching tube S4, switching tube S6 and switching tube S2 are respectively connected with ABC three phases of permanent magnet synchronous motor PMSM, and the connection places are respectively connected with capacitor C f . The other end of switching tube S4 is connected with one end of diode D4, the other end of switching tube S6 is connected with one end of diode D6, the other end of switching tube S2 is connected with one end of diode D2, and the other end of DC-DC converter is connected with the other end of diode D4, diode D6 and diode D2.

[0024] The application is to provide a current source inverter short-circuit fault diagnosis method based on phase current and mixed error of average absolute value thereof, the three-phase current is divided by the park vector module value for normalization processing, based on the reference current and actual current error and the average absolute value and average value error of the normalized current, the mixed diagnosis variable and auxiliary variable are generated, the preset threshold and variable combination logic are combined, the accurate positioning of single tube short circuit, same side and different phase double tube short circuit and different side and different phase double tube short circuit is realized. The application does not need additional voltage sensor, and the robustness and multi-type fault compatibility of fault diagnosis are significantly improved. Specific embodiment two The present invention provides a current source inverter short circuit fault diagnosis method based on phase current and its mean absolute value mixed error. The method is implemented based on a current source inverter driven permanent magnet synchronous motor system based on phase current and its mean absolute value mixed error. The method includes the following steps: Step 1: Real-time acquisition of the ABC three-phase current of the permanent magnet synchronous motor during the operation of the current source inverter-driven permanent magnet synchronous motor i a , i b , i c , and filter and reduce noise on it; Step 2: Calculate by Park transform i d and i q , and then obtain the Park vector modulus value, divide the three-phase current by the Park vector modulus value to normalize the phase current ; Step 3: Generate a hybrid diagnostic variable based on the reference current, actual current error, and the mean absolute and mean errors of the normalized current. e and auxiliary diagnostic variables M ; Step 4: Combine the preset threshold and variable combination logic to achieve accurate positioning of single-tube short circuit, same-side out-of-phase double-tube short circuit, and opposite-side out-of-phase double-tube short circuit.

[0026] The present invention is a current source inverter short-circuit fault diagnosis method based on a mixed error of phase currents and their average absolute values. The method normalizes the three-phase currents by dividing them by the Park vector modulus. Based on the reference current, actual current errors, and the average absolute value and average value errors of the normalized currents, mixed diagnostic variables and auxiliary diagnostic variables are generated. Combined with preset thresholds and variable combination logic, the method accurately locates single-transistor short circuits, same-side out-of-phase dual-transistor short circuits, and opposite-side out-of-phase dual-transistor short circuits. By combining the reference current error with the normalized current error, the present invention enhances load independence and fault sensitivity, addressing the problem of a single error quantity being sensitive to transient load fluctuations. It eliminates the need for additional voltage sensors and significantly improves the robustness of fault diagnosis and compatibility with multiple types of faults. Specific embodiment three: The only difference between the third embodiment of the present application and the second embodiment is that: In step 2, normalization is performed by dividing the motor phase current by the Park vector modulus. The normalized motor phase current obtained is given by the following formula:

[0028] Specific embodiment four: The difference between the embodiment four and the embodiment three of the present application is only that: The auxiliary diagnosis variable in step 3 M The reaction is the average characteristic in each phase current cycle when the pipe has a short circuit fault, and the variable e, M The formula is as follows:

[0030]

[0031] Wherein, α, β are weight coefficients, and by default, α = 0.3 and β = 0.7, is a reference current, is an actual current, represents the average absolute value of the motor phase current; represents the average value in the phase current cycle; L represents that the average value in the phase current cycle is negative; and H represents that the average value in the phase current cycle is positive. Embodiment five: The difference between the embodiment five and the embodiment four of the present application is only that: M n The reaction is the average characteristic in each phase current cycle when the pipe has a short circuit fault, wherein L represents that the average value in the phase current cycle is negative, and H represents that the average value in the phase current cycle is positive. Embodiment six: The difference between the embodiment six and the embodiment five of the present application is only that: S is used to distinguish the same side and different phase double pipe fault S = 3, and the different side and different phase double pipe fault S = 2; the auxiliary variable E n N in the auxiliary variable represents that the pipe is in a normal working state; P represents a single pipe fault; Q represents a same side and different phase double pipe fault; and D represents a different side and different phase double pipe fault, k 1, k 2 are determined threshold values; E n Only a fault existing in a certain phase can be determined, and the specific position of the upper bridge arm or the lower bridge arm cannot be accurately positioned, and finally the auxiliary variable M n is still needed to combine to locate the specific position of the abnormal pipe. Embodiment seven: The difference between the embodiment seven and the embodiment six of the present application is only that: When the inverter appears the following situations: e a k 1, e b k 1,​​e c > k 1; ( M a , M b , M c )=(1,-1,-1), by e a < k 1 Knowing that a single-tube fault has occurred in the inverter, and the fault phase is phase A, and according to ( M a , M b , M c )=(1,-1,-1) It is judged that phase A is H, which means the upper tube is short-circuited, so the tube with short-circuit fault is T1. Specific embodiment eight: The only difference between the eighth embodiment of the present invention and the seventh embodiment is that: When the inverter has the following conditions: e a > k 2, e b > k 2, e c < k 2; ( M a , M b , M c )=(1,1,-1); S=3, by e a > k 2, e b > k 2, e c < k 2. S=3 E n =Q, that is, there is a double-tube fault on the same side with different phases, k 2< e n The corresponding two phases are the fault phases. M a , M b , M c )=(1,1,-1) It is judged that the phases A and B are H, which means that the upper tube is abnormal, so the tubes with short circuit fault are T1 and T3. Embodiment nine: The difference between the embodiment nine and the embodiment eight is only that: The application provides a computer readable storage medium, which stores a computer program, and the program is executed by a processor to realize a current source inverter short-circuit fault diagnosis method based on phase current and average absolute value mixed error of the phase current.

[0037] The method comprises the following steps: Step 1: collecting ABC three-phase currents of the permanent magnet synchronous motor in real time during driving the permanent magnet synchronous motor to run by the current source inverter i a , i b , i c and filtering and denoising the currents; Step 2: calculating i d and i q , and then obtaining a Park vector module value, and normalizing the three-phase currents by dividing the three-phase currents by the Park vector module value ; Step 3: generating a mixed diagnosis variable based on a reference current and actual current error and average absolute value and average value error of the normalized current e and an auxiliary diagnosis variable M ; Step 4: combining a preset threshold and variable combination logic to realize accurate positioning of single tube short circuit, same side and different phase double tube short circuit and different side and different phase double tube short circuit. Embodiment ten: The difference between the embodiment ten and the embodiment nine is only that: The application provides a computer device, which comprises a memory and a processor, the memory stores a computer program, and the processor realizes a current source inverter short-circuit fault diagnosis method based on phase current and average absolute value mixed error of the phase current when executing the computer program.

[0039] The method comprises the following steps: Step 1: collecting ABC three-phase currents of the permanent magnet synchronous motor in real time during driving the permanent magnet synchronous motor to run by the current source inverter i a , i b , i c and filtering and denoising the currents; Step 2: calculating i d and iq , and then the three-phase current is divided by the Park vector modulus value to normalize the three-phase current ; Step 3: Based on the reference current and actual current error and the average absolute value and average value error of the normalized current, a mixed diagnostic variable and an auxiliary diagnostic variable are generated e ; M ; Step 4: Combined with a preset threshold and variable combination logic, the precise positioning of single tube short circuit, same side and different phase double tube short circuit, and different side and different phase double tube short circuit is realized. Eleventh embodiment: The difference between the eleventh embodiment of the application and the tenth embodiment is only that: Step 1: Real-time acquisition of ABC three-phase current of the permanent magnet synchronous motor during driving the permanent magnet synchronous motor to run by the current source inverter i a , i b , i c , and filtering and noise reduction processing is performed.

[0041] Step 2: Park transformation is calculated i d and i q , and then the Park vector modulus value is obtained, and then the three-phase current is divided by the Park vector modulus value to normalize the three-phase current.

[0042]

[0043]

[0044] wherein is the Park vector modulus value, is the normalized phase current.

[0045] Step 3: Based on the reference current and actual current error and the average absolute value and average value error of the normalized current, a mixed diagnostic variable and an auxiliary diagnostic variable are generated e . The mixed diagnostic variable M is obtained by subtracting the reference current and the actual current and the average absolute value of the normalized motor phase current under normal operating conditions e minus the average absolute value of the normalized motor phase current after failure. The auxiliary diagnostic variable reflects the average value characteristics of each phase current in a period when the tube has a short circuit fault. The variable M The formula of e, M is as follows:

[0046]

[0047] where a, b are weight coefficients, a = 0.3, b = 0.7 by default, which can be dynamically adjusted according to the load. is the reference current, is the actual current, represents the average absolute value of the motor phase current; represents the average value in the phase current cycle; L represents the average value in the phase current cycle is negative; H represents the average value in the phase current cycle is positive.

[0048] Step four, combining the preset threshold and variable combination logic, the precise positioning of single tube short circuit, same side and different phase double tube short circuit, and different side and different phase double tube short circuit is realized.

[0049] Specifically, the fault types that may occur in the running process of the inverter mainly include the following types: single tube fault, double tube fault (same side and different phase double tube fault, different side and different phase double tube fault), three tube fault, and phase current characteristics such as Figure 3 .

[0050] The measured motor phase current is standardized using the Park vector module, which is defined as:

[0051]

[0052] where, i d and i q are the Park vector components, i a , i b and i c are the motor output three-phase currents. The Park vector module is given by:

[0053] Normalization is performed by dividing the motor phase current by the Park vector module. The obtained normalized motor phase current is given by:

[0054] where n = a , b , c . Therefore, assuming that the motor is powered by a healthy inverter, which generates a perfectly balanced three-phase sinusoidal current system:

[0055] where I m is the maximum amplitude of the current, ω s is the frequency of the motor current, φ is the initial phase angle, it can be proved that the Park vector modulus can be given by:

[0056] As a result of this normalization process, the normalized motor phase current will always take values in the range ± 2 / 3, independently of the measured motor phase current amplitude, because:

[0057] As a result of this normalization process, the normalized phase current will always take values in the range ± The average value of the motor phase current and the average absolute value can be given by:

[0058]

[0059] where N is the number of current samples during each fundamental period and k is the sampling instant. In one period, when N tends to infinity, it can be expressed in integral form:

[0060]

[0061] Finally, the hybrid diagnostic variable e n is given by:

[0062] where α, β are weight coefficients, by default α = 0.3 and β = 0.7, which can be dynamically adjusted according to the load. is the reference current, is the actual current, represents the average absolute value of the motor phase current, is a constant value, the normalized average absolute value of the motor phase current under normal operating conditions, i.e.:

[0063] For the mixed diagnostic variable, which reflects the error between the normalized reference current and the actual current and the difference between the average absolute value and the average value of the normalized current under normal operation of the motor, under normal circumstances, the mixed diagnostic variable should be close to 0, and when the motor has a short-circuit fault, the actual phase current and the average absolute value corresponding to a certain item will deviate, so that the diagnostic variable deviates from 0 and becomes a positive value, so the mixed diagnostic variable e n can be used to detect abnormal inverters. On the other hand, these variables cannot perform complete inverter diagnosis, because they only carry information about the affected phase, and the comprehensive fault diagnosis type is mainly divided into single tube fault, same side and different phase double tube fault, and different side and different phase double tube fault (when three switches are short-circuited at the same time, it means that there is a faulty switch in each phase. The output current waveform after failure of the three switch tubes is similar to that of two upper switch tubes or two lower switch tubes. Therefore, the detection method based on the output current can only locate two switches. In actual application, when one or two switches are short-circuited, after the detection algorithm detects the switch, the system either stops running or switches to a fault-tolerant bridge arm to continue running). The faulty tube can be determined according to the following judgment flow:

[0064]

[0065]

[0066] wherein the auxiliary variable M n can be used in combination with S, E n to locate the faulty tube. M n reflects the average value characteristics of each phase current in a period when the tube has a short-circuit fault, wherein L represents that the average value of the phase current in a period is negative, and H represents that the average value of the phase current in a period is positive. S can distinguish between same side and different phase double tube fault (S=3) and different side and different phase double tube fault (S=2) when double tube fault occurs. The auxiliary variable E n N in the auxiliary variable k 1, k 2 is a determined threshold value.

[0067] only E n can determine that there is a fault in a certain phase, but cannot accurately locate the upper bridge arm or the lower bridge arm, and finally needs to be combined with the auxiliary variable M n to locate the specific position of the abnormal tube.

[0068] For example, when the inverter has the following conditions: e a k 1, e b k 1, e c k 1); ( M a M b M c =(1,-1,-1). Then it can be known that e a k 1Firstly, it is known that the inverter has a single tube fault, and the fault phase is phase A. Then according to M a M b M c =(1,-1,-1), it is judged that phase A is H, which is an upper tube short circuit, and thus the tube with short circuit is T1. If the inverter has the following conditions: e a k 2, e b k 2, e c k 2); ( M a M b M c =(1,1,-1); S=3. Then it can be known firstly that e a k 2, e b k 2, e c k 2), S=3 E n =Q, which is a same side and different phase double tube fault, k 2 e n The corresponding two phases are fault phases. Then according to M a M b M ​​​​​​​​​​​​​​​​​​c )=(1,1,-1) can judge that A, B phase is H, which is an abnormal pipe, so the pipe with short circuit fault is T1, T3. Table 1 is a fault detection rule table.

[0069] Table 1 Fault detection rule table

[0070] The application is a current source inverter short circuit fault diagnosis method based on phase current and average absolute value mixed error. The three-phase current is divided by the Park vector module value for normalization processing. Based on the reference current and actual current error and the average absolute value and average value error of the normalized current, a mixed diagnosis variable and an auxiliary diagnosis variable are generated. Combined with the preset threshold and variable combination logic, the single pipe short circuit, same side and different phase double pipe short circuit and different side and different phase double pipe short circuit are accurately positioned. The application combines the reference current error with the normalized current error, enhances the load independence and fault sensitivity, solves the problem of single error quantity sensitive to transient load fluctuation, does not need additional voltage sensor, and significantly improves the robustness and multi-type fault compatibility of fault diagnosis.

[0071] The above is only a preferred embodiment of the current source inverter short circuit fault diagnosis method based on phase current and average absolute value mixed error. The protection scope of the current source inverter short circuit fault diagnosis method based on phase current and average absolute value mixed error is not limited to the above-mentioned embodiments. Any technical solution under the same idea belongs to the protection scope of the application. It should be noted that for those skilled in the art, some improvements and changes without departing from the principles of the application should also be considered as the protection scope of the application.

Claims

1. A permanent magnet synchronous motor system driven by a current source inverter based on a mixed error of phase current and its mean absolute value, characterized by: The system comprises: Voltage source, DC-DC converter, inductor L dc , switch tube S1, switch tube S2, switch tube S3, switch tube S4, switch tube S5, switch tube S6, diode D1, diode D2, diode D3, diode D4, diode D5, diode D6, capacitor C f and permanent magnet synchronous motors (PMSM); The two sides of the voltage source are connected to the DC-DC converter, and one end of the DC-DC converter is connected to the inductor L dc One end of the inductor L dc The other end of the switch is connected to one end of the switch tube S1, the switch tube S3 and the switch tube S5, the other end of the switch tube S1 is connected to one end of the diode D1, the other end of the switch tube S3 is connected to one end of the diode D3, and the other end of the switch tube S5 is connected to one end of the diode D5; The other end of diode D1 is connected to one end of switch tube S4, the other end of diode D3 is connected to one end of switch tube S6, and the other end of diode D5 is connected to one end of switch tube S2; switch tubes S4, S6 and S2 are connected to the ABC three phases of permanent magnet synchronous motor PMSM respectively, and the connection points are connected to capacitors C f ; The other end of the switch tube S4 is connected to one end of the diode D4, the other end of the switch tube S6 is connected to one end of the diode D6, the other end of the switch tube S2 is connected to one end of the diode D2, and the other end of the DC-DC converter is connected to the diode D4, the diode D6 and the other end of the diode D2.

2. A method for diagnosing short-circuit faults in a current source inverter based on a mixed error of phase current and its mean absolute value, the method being implemented based on the system of claim 1, and characterized by: The method comprises the following steps: Step 1: Real-time acquisition of the ABC three-phase current of the permanent magnet synchronous motor during the operation of the current source inverter-driven permanent magnet synchronous motor i a , i b , i c , and filter and reduce noise on it; Step 2: Calculate by Park transform i d and i q , and then obtain the Park vector modulus value, divide the three-phase current by the Park vector modulus value to normalize the phase current ; Step 3: Generate a hybrid diagnostic variable based on the reference current, actual current error, and the mean absolute and mean errors of the normalized current. e and auxiliary diagnostic variables M ; Step 4: Combine the preset threshold and variable combination logic to achieve accurate positioning of single-tube short circuit, same-side out-of-phase double-tube short circuit, and opposite-side out-of-phase double-tube short circuit.

3. The method according to claim 2, wherein: In step 2, normalization is performed by dividing the motor phase current by the Park vector modulus. The normalized motor phase current obtained is given by the following formula:

4. The method according to claim 3, wherein: Auxiliary diagnostic variables in step 3 M It reflects the mean value characteristics of each phase current cycle when a short circuit occurs in the tube. e、M The formula is as follows: Among them, α and β are weight coefficients, the default α=0.3, β=0.7, is the reference current, is the actual current, Represents the average absolute value of the motor phase current; Represents the mean value within the phase current cycle; L represents that the mean value within the phase current cycle is negative; H represents that the mean value within the phase current cycle is positive.

5. The method according to claim 4, wherein: M n It reflects the mean characteristics of each phase current cycle when a short circuit fault occurs in the tube, where L represents a negative mean value in the phase current cycle, and H represents a positive mean value in the phase current cycle.

6. The method according to claim 5, wherein: S To distinguish between double-tube faults, S=3 for double-tube faults on the same side with different phases, S=2 for double-tube faults on different sides with different phases; auxiliary variables E n N in the code indicates that the tube is in normal working condition; P indicates a single tube failure. Q represents a double-tube fault on the same side with different phases; D represents a double-tube fault on different sides and in different phases. k 1, k 2 is the determined threshold; E n It can only be determined that there is a fault in a certain phase, but it cannot be accurately located in the upper bridge arm or the lower bridge arm. Finally, it is necessary to combine auxiliary variables M n Locate the specific location of the abnormal pipe.

7. The method according to claim 6, wherein: When the inverter has the following conditions: e a < k 1, e b > k 1, e c > k 1; ( M a , M b , M c )=(1,-1,-1), by e a < k 1 Knowing that a single-tube fault has occurred in the inverter, and the fault phase is phase A, and according to ( M a , M b , M c )=(1,-1,-1) It is judged that phase A is H, which means the upper tube is short-circuited, so the tube with short-circuit fault is T1.

8. The method according to claim 6, wherein: When the inverter has the following conditions: e a > k 2, e b > k 2, e c < k 2; ( M a , M b , M c )=(1,1,-1); S=3, by e a > k 2, e b > k 2, e c < k 2. S=3 E n =Q, that is, there is a double-tube fault on the same side with different phases, k 2< e n The corresponding two phases are the fault phases. M a , M b , M c )=(1,1,-1) It is judged that the phases A and B are H, which means that the upper tube is abnormal, so the tubes with short circuit fault are T1 and T3.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: The program is executed by a processor to implement the method according to claims 2 to 8.

10. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the method of claims 2 to 8 is implemented.

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