Zero-voltage vector multi-pulse belt speed restarting method

Abstract

The invention discloses a zero-voltage vector multi-pulse belt speed restarting method, which relates to the technical field of motor control, and comprises the following steps: calculating a winding short circuit coefficient by collecting multiple parameters such as current, voltage, temperature and electric leakage charge quantity in real time, and performing three-stage processing: continuously monitoring in normal; during turn-to-turn short circuit, a self-adaptive pulse width dynamic compensation algorithm is adopted to adjust fault phase voltage, inductance symmetry is recovered, inflection points, namely evolution values, of an inductance trend model are analyzed in combination with a second derivative, and the fault upgrading risk is predicted; and the machine is stopped immediately if interphase short circuit occurs. Through the multi-parameter fusion diagnosis and dynamic compensation strategy, the belt speed restarting detection precision is improved, and the serious short circuit risk is warned in advance.

Description

Technical Field

[0001] The present invention relates to the technical field of motor control, and specifically to a speed - resuming method with zero - voltage vector multi - pulses. Background Art

[0002] The permanent - magnet synchronous motor is a type of motor with high efficiency and energy conservation, and is widely used in fields such as rail transit, electric vehicles, industrial drives, aerospace, and household appliances. By converting electrical energy into mechanical energy to drive equipment operation, its core advantages lie in high power density, small volume, high efficiency, and precise speed - control ability, and it is particularly suitable for scenarios with demanding performance and energy - efficiency requirements, such as high - speed rail traction systems, new - energy vehicle powertrains, numerical - control machine - tool servo systems, and variable - frequency air - conditioner compressors.

[0003] When the motor is in the coasting (still rotating) state due to a fault or power failure, by applying multiple short - term zero - voltage vector pulses (i.e., momentary short - circuits) to the stator windings of the motor, the real - time speed and rotor position of the motor can be quickly and accurately estimated using the variation law of the short - circuit current, thereby achieving a safe restart under the condition of no position sensor.

[0004] Both the stator and rotor of the motor are wound with coils, that is, windings. After being energized, a magnetic field is generated to drive the motor to rotate. The wires of the coils are separated by insulating materials. However, if the insulation layer of the coil is damaged, the originally isolated coils come into contact, causing a short - circuit in the winding. On this basis, the accuracy of estimating the real - time speed and real - time position of the rotor of the motor using the variation law of the short - circuit current is reduced. Summary of the Invention

[0005] Technical Problem to be Solved

[0006] Aiming at the deficiencies of the prior art, the present invention provides a speed - resuming method with zero - voltage vector multi - pulses, which solves the problem that the short - circuit of the stator and rotor windings of the motor due to the damage of the insulation layer interferes with the variation law of the short - circuit current and reduces the accuracy of estimating the real - time speed and rotor position of the motor.

[0007] Technical Solution

[0008] To achieve the above objectives, the present invention is realized through the following technical solutions: A zero-voltage vector multi-pulse belt speed re-injection method, including the following specific steps: Step 1: Real-time obtain current data, voltage data, power supply frequency data, resistance, thermal imaging, high-frequency instantaneous voltage at the leakage point, and capacitance, and perform comprehensive calculations to obtain the winding short-circuit coefficient; Step 2: Based on the winding short-circuit coefficient, three situations are judged for whether the winding is short-circuited. The first judgment is that the winding is normal, and return to Step 1 to repeat the above operations, then detect through zero-voltage vector multi-pulses to obtain the evolution value. The second judgment is inter-turn short-circuit. First, perform inductance dynamic compensation on a certain phase among the three phases through the adaptive pulse width dynamic compensation algorithm, then detect through zero-voltage vector multi-pulses, and predict the evolution of inter-turn short-circuit into phase-to-phase short-circuit, and return to Step 1 to repeat the above operations. The third judgment is phase-to-phase short-circuit, then directly stop the motor operation and issue a maintenance required prompt; Step 3: Predict whether the inter-turn short-circuit evolves into a phase-to-phase short-circuit according to the evolution value. If the predicted trend is inter-turn short-circuit, first perform dynamic compensation through the adaptive pulse width dynamic compensation algorithm, then detect through zero-voltage vector multi-pulses, and predict the evolution of inter-turn short-circuit into phase-to-phase short-circuit, and return to Step 1 to repeat the above operations. If the predicted trend is phase-to-phase short-circuit, then directly stop the motor operation and issue a maintenance required prompt.

[0009] Further, in Step 1, perform data cleaning on the current data, voltage data, and power supply frequency data. Calculate the resistance by the volt-ampere method for the current data and voltage data. Calculate the average inductance by taking the average value of the current data, voltage data, power supply frequency data, and resistance and then performing calculations through the inductance phase difference method. As time goes by, perform normalization processing on the average inductance and perform comprehensive calculations to obtain the inductance anomaly coefficient.

[0010] Further, in Step 1, perform filtering and noise reduction processing on the thermal imaging. Convert the color in the thermal imaging to RGB values through the color conversion RGB value tool. The RGB values include the red channel value, green channel value, and blue channel value. As time goes by, perform normalization processing on the RGB values and perform comprehensive calculations to obtain the temperature anomaly coefficient.

[0011] Further, in Step 1, perform data cleaning processing on the high-frequency instantaneous voltage. Calculate the charge at the leakage point by multiplying the high-frequency instantaneous voltage and the capacitance according to the capacitance energy storage formula. Perform normalization processing on the inductance anomaly coefficient, temperature anomaly coefficient, and the charge at the leakage point and perform comprehensive calculations to obtain the winding short-circuit coefficient.

[0012] Further, the specific method for obtaining the winding short-circuit coefficient is: RX = WY - DY + DH; where RX represents the winding short-circuit coefficient, WY represents the temperature anomaly coefficient, DY represents the inductance anomaly coefficient, and DH represents the charge at the leakage point.

[0013] Further, in step two, set the inter-turn short-circuit interval according to historical experimental data. If the winding short-circuit coefficient is less than the lower limit of the inter-turn short-circuit interval, it is determined that the motor is normal. If the winding short-circuit coefficient is within the range of the winding short-circuit coefficient, it is determined that there is an inter-turn short-circuit. If the winding short-circuit coefficient is greater than the upper limit of the inter-turn short-circuit interval, it is determined that there is an inter-phase short-circuit.

[0014] Further, the specific steps for dynamically compensating the real-time speed and rotor real-time position of a motor with inter-turn short-circuit through the adaptive pulse width dynamic compensation algorithm are as follows: Compare the inductances of the three phases respectively. According to the inductance phase difference method, the phase with reduced inductance is judged as the fault phase, and the voltage of this phase is increased in real time for the fault phase. Calculate the current data through the variance method to obtain the current stable value. Summarize the current data of the normal operation of the motor to obtain the current stable dynamic threshold. Compare the current stable value with the current stable dynamic threshold. If the current stable value is within the current stable dynamic threshold, stop increasing the voltage of this phase. If the current stable value is not within the current stable dynamic threshold, continue to increase the voltage of this phase until the current stable value is within the current stable dynamic threshold.

[0015] Further, the specific way to obtain the evolution value is as follows: Establish a mathematical model according to the characteristic of the accelerating decline trend of inductance to obtain the inductance trend model. Take the second derivative of the inductance trend model. When the second derivative of this model is equal to zero, obtain the evolution value.

[0016] Further, in step three, compare the current inductance with the evolution value in real time. If the current inductance is less than the evolution value, the predicted trend is inter-turn short-circuit. If the current inductance is greater than or equal to the evolution value, the predicted trend is inter-phase short-circuit.

[0017] Beneficial effects

[0018] Compared with the prior art, the embodiments of the present invention have at least the following advantages or beneficial effects:

[0019] 1. By real-time monitoring multi-dimensional parameters such as current, voltage, temperature, and leakage charge amount, calculating the winding short-circuit coefficient, and combining with the adaptive pulse width dynamic compensation algorithm, the inductances of the fault phase and the normal phase are made symmetric again, eliminating the interference of current fluctuations on the multi-pulse detection of the zero voltage vector, and improving the estimation accuracy of the real-time speed and rotor position of the motor.

[0020] 2. Based on the characteristic of the accelerating decline trend of inductance, establish a convex-concave function model that monotonically decreases, take the second derivative of the inductance trend model, and predict whether the inter-turn short-circuit will evolve into an inter-phase short-circuit, which helps workers repair the motor in advance, avoid serious damage to the motor, reduce the repair cost and lower the safety risk.

[0021] Of course, it is not necessary for any product implementing the present invention to simultaneously achieve all the advantages described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 For the present invention: a flowchart of a belt speed re-injection method with zero voltage vector multi-pulses. DETAILED DESCRIPTION OF THE INVENTION

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0024] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variation thereof are intended to cover a non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or device.

[0025] As Figure 1 shown, the embodiments of the present invention provide a belt speed re-injection method with zero voltage vector multi-pulses, which includes the following specific steps:

[0026] Step 1: Real-time obtain current data through a current sensor, real-time obtain voltage data through a voltage sensor, and real-time obtain power supply frequency data through a frequency meter. Clean the current data, voltage data, and power supply frequency data to remove redundant information in the current data, voltage data, and power supply frequency data, improve the accuracy of the data. Calculate the current data and voltage data by the voltammetry method, quantify the resistance through the linear relationship between the voltage data and the current data to obtain the resistance. Since the industrial motor has three phase differences, the current data, voltage data, power supply frequency data, and resistance of each phase are independent. Therefore, take the average value of the current data, voltage data, power supply frequency data, and resistance by the inductance phase difference method and then calculate. Utilize the characteristic that there is a phase difference between the voltage and the current in alternating current, and combine the power supply frequency data and the resistance for quantification to obtain the average inductance. Due to the damage of the coil insulation layer, resulting in inter-turn short circuit, the number of turns decreases, and thus the average inductance decreases. Over time, normalize the average inductance and perform comprehensive calculations to obtain the inductance anomaly coefficient;

[0027]

[0028] Among them, DY represents the inductance anomaly coefficient, reflecting whether the average inductance decreases. t represents time, and DG t+1 represents the average inductance at the (t + 1)-th moment, and DG t represents the average inductance at the t-th moment. If the average inductance decreases, the inductance anomaly coefficient is negative and gradually decreases.

[0029] Thermal imaging is obtained in real time through a thermal imager, and filtering and noise reduction processing are performed on the thermal imaging, which helps to improve the quality of the thermal imaging. The colors in the filtered and noise-reduced thermal imaging are converted into RGB values through a color conversion RGB value tool. The RGB values include red channel values, green channel values, and blue channel values, and the range of each channel value is from 0 to 255. Since winding short circuits will cause the resistance to decrease and the current to surge, according to the Joule heating effect, the square of the current is proportional to the heat. Therefore, winding short circuits will cause the temperature to gradually increase, resulting in an increasing proportion of red in the thermal imaging and an increase in the red channel value. As time goes by, the RGB values are normalized and comprehensively calculated to obtain the temperature anomaly coefficient;

[0030]

[0031] Among them, WY represents the temperature anomaly coefficient, reflecting whether the temperature is abnormal. t represents time, and HT t+1 represents the red channel value at the (t + 1)-th moment, VT t+1 represents the green channel value at the (t + 1)-th moment, LT t+1 represents the blue channel value at the (t + 1)-th moment, HT t represents the red channel value at the t-th moment, VT t represents the green channel value at the t-th moment, LT t represents the blue channel value at the t-th moment. Since the red channel value gradually increases over time, the ratio of the red channel value at the (t + 1)-th moment to the red, green, and blue channel values is larger than the ratio of the red channel value at the t-th moment to the red, green, and blue channel values. Therefore, is greater than 1, so the temperature anomaly coefficient is greater than zero and gradually increases.

[0032] Due to the damage of the insulation layer, leakage occurs at the damaged part. The high-frequency instantaneous voltage at the leakage part is obtained in real time through a high-frequency voltage pulse sensor, and data cleaning processing is performed on the high-frequency instantaneous voltage, which helps to remove the redundancy in the high-frequency instantaneous voltage. The capacitance is obtained from the motor specifications, and the product of the high-frequency instantaneous voltage and the capacitance is calculated according to the capacitance energy storage formula to obtain the charge amount at the leakage part. The more serious the damage of the insulation layer, the greater the charge amount at the leakage part.

[0033] Normalize and comprehensively calculate the inductance anomaly coefficient, temperature anomaly coefficient, and the charge quantity at the leakage point to obtain the winding short - circuit coefficient;

[0034] RX = WY - DY+DH;

[0035] Among them, RX represents the winding short - circuit coefficient, which reflects whether the winding of the motor is short - circuited and the severity of the insulation layer damage. WY represents the temperature anomaly coefficient, which reflects whether the temperature is abnormal. DY represents the inductance anomaly coefficient, which reflects whether the average inductance decreases. Since the inductance anomaly coefficient is negative, the negative sign is taken as positive. DH represents the charge quantity at the leakage point.

[0036] Step 2: Judge whether the winding is short - circuited according to the winding short - circuit coefficient. Winding short - circuit includes turn - to - turn short - circuit and phase - to - phase short - circuit. Turn - to - turn short - circuit means that part of the winding is short - circuited, which reduces the operating performance of the motor and increases the probability of evolving into phase - to - phase short - circuit over time. Phase - to - phase short - circuit means a short - circuit across phases. That is, an industrial motor is a three - phase motor, and the voltages with three phase differences make the motor rotor rotate by itself without an additional starting device. Phase - to - phase short - circuit will cause an instant open - circuit, and its severity is much greater than that of turn - to - turn short - circuit. Therefore, set the turn - to - turn short - circuit interval according to historical experimental data. If the winding short - circuit coefficient is less than the lower limit of the turn - to - turn short - circuit interval, it is judged that the motor is normal. Subsequently, detect the real - time speed and rotor real - time position of the motor through zero - voltage vector multi - pulse and return to Step 1 to repeat the above operations. If the winding short - circuit coefficient is within the range of the winding short - circuit coefficient, it is judged as turn - to - turn short - circuit. Dynamically compensate the real - time speed and rotor real - time position of the motor with turn - to - turn short - circuit through the adaptive pulse - width dynamic compensation algorithm. Subsequently, detect the real - time speed and rotor real - time position of the motor through zero - voltage vector multi - pulse and predict the severity of the turn - to - turn short - circuit to obtain an evolution value, and return to Step 1 to repeat the above operations. After the motor has a turn - to - turn short - circuit and has to operate, avoid the turn - to - turn short - circuit evolving into a phase - to - phase short - circuit. If the winding short - circuit coefficient is greater than the upper limit of the turn - to - turn short - circuit interval, it is judged as phase - to - phase short - circuit, and directly stop the motor operation and issue a maintenance - required prompt.

[0037] The specific steps of dynamically compensating the real - time speed and rotor real - time position of the motor with turn - to - turn short - circuit through the adaptive pulse - width dynamic compensation algorithm are as follows:

[0038] Due to the turn - to - turn short - circuit, the number of turns decreases, and then a faulty phase appears, that is, the phase that fails among the three phases, resulting in a decrease in the average inductance, causing asymmetry in the inductance between the faulty phase and the normal phase among the three phases. Furthermore, it causes the current in the motor to be unstable. The fluctuation of the current superimposed on the noise increases the error in detecting the real - time speed and rotor real - time position of the motor through the zero - voltage vector multi - pulse. Compare the inductances of the three phases respectively. According to the inductance phase - difference method, the phase with reduced inductance is judged as the faulty phase, and the voltage of this phase is increased in real - time for the faulty phase to increase the inductance of this phase. Calculate the current stability value through the variance method for the current data. Summarize the current data of the normal operation of the motor to obtain the current stability dynamic threshold. Compare the current stability value with the current stability dynamic threshold. If the current stability value is within the current stability dynamic threshold, stop increasing the voltage of this phase. If the current stability value is not within the current stability dynamic threshold, continue to increase the voltage of this phase until the current stability value is within the current stability dynamic threshold. This helps to improve the accuracy of increasing the voltage of the faulty phase, make the inductance between the faulty phase and the normal phase among the three phases symmetric, and further avoid the reduction in the accuracy of detecting the real - time speed and rotor real - time position of the motor through the zero - voltage vector multi - pulse.

[0039] The specific way to obtain the evolution value is as follows:

[0040] Since the turn - to - turn short - circuit has a probability of evolving into an inter - phase short - circuit over time. If the turn - to - turn short - circuit evolves into an inter - phase short - circuit, the severity of the winding short - circuit increases, and the trend of inductance decrease accelerates. That is, according to this characteristic, a mathematical model is established. This mathematical model is monotonically decreasing, and from slow to fast, the slow part is convex and the fast part is concave, obtaining an inductance trend model. Therefore, the second - order derivative of the inductance trend model is calculated. When the second - order derivative of this model is equal to zero, this inductance is the inflection point, that is, the evolution value.

[0041] Step 3: Judge whether the turn - to - turn short - circuit evolves into an inter - phase short - circuit over time according to the evolution value. Compare the current inductance with the evolution value in real - time. If the current inductance is less than the evolution value, it is judged as a turn - to - turn short - circuit, that is, the winding short - circuit coefficient is within the range of the winding short - circuit coefficient. According to the adaptive pulse - width dynamic compensation algorithm in Step 2, dynamically compensate the real - time speed and rotor real - time position of the motor with turn - to - turn short - circuit. Subsequently, detect the real - time speed and rotor real - time position of the motor through the zero - voltage vector multi - pulse and return to Step 1 to repeat the above operations. If the current inductance is greater than or equal to the evolution value, it is judged as an inter - phase short - circuit. Stop the motor operation directly and issue a maintenance - required prompt according to Step 2. Predicting that the motor evolves from a turn - to - turn short - circuit to an inter - phase short - circuit helps workers repair the motor in advance, avoid serious damage to the motor, reduce the repair cost and lower the safety risk.

[0042] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and variations can be made according to the content of this specification. These embodiments are selected and specifically described in this specification in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A zero voltage vector multi-pulse belt speed re-throwing method, characterized in that: The specific steps include: Step 1: Obtain current data, voltage data, power frequency data, resistance, thermal imaging, high-frequency instantaneous voltage at the leakage point, and capacitance in real time and perform comprehensive calculations to obtain the winding short-circuit coefficient; Step 2: According to the winding short-circuit coefficient, three situations are judged to determine whether the winding is short-circuited. The first situation is that the winding is normal, and the above operation is repeated in step 1. Then, the zero voltage vector multi-pulse is used for detection to obtain the evolution value. The second situation is that it is a turn-to-turn short circuit. The inductance dynamic compensation algorithm is firstly used to dynamically compensate for one of the three phases, and then the zero voltage vector multi-pulse is used for detection. The evolution of the turn-to-turn short circuit into the phase-to-phase short circuit is predicted, and the above operation is repeated in step 1. The third situation is that it is a phase-to-phase short circuit, and the motor is directly stopped and a prompt for maintenance is issued; Step 3: Predict whether the turn-to-turn short circuit will evolve into a phase-to-phase short circuit based on the evolution value. If the predicted trend is a turn-to-turn short circuit, first perform dynamic compensation through the adaptive pulse width dynamic compensation algorithm, then detect through zero voltage vector multi-pulses, and predict whether the turn-to-turn short circuit will evolve into a phase-to-phase short circuit, and return to step 1 to repeat the above operations. If the predicted trend is a phase-to-phase short circuit, stop the motor directly and issue a maintenance prompt.

2. A zero voltage vector multi-pulse belt speed re-throwing method according to claim 1, characterized in that: In step one, the current data, voltage data and power supply frequency data are cleaned, the current data and voltage data are calculated by the volt-ampere method to obtain the resistance, the current data, voltage data, power supply frequency data and resistance are averaged and then calculated by the inductance phase difference method to obtain the average inductance, and the average inductance is normalized and comprehensively calculated over time to obtain the inductance abnormality coefficient.

3. A zero voltage vector multi-pulse belt speed re-casting method according to claim 1, characterized in that: In step one, the thermal image is filtered and denoised, and the color in the thermal image is converted to RGB value using a color conversion RGB value tool. The RGB value includes a red channel value, a green channel value, and a blue channel value. The RGB value is normalized and comprehensively calculated over time to obtain a temperature anomaly coefficient.

4. A zero voltage vector multi-pulse belt speed re-casting method according to claim 1, characterized in that: In step one, the high-frequency instantaneous voltage is cleaned and processed, and the product of the high-frequency instantaneous voltage and the capacitance is calculated according to the capacitor energy storage formula to obtain the charge at the leakage point, and the inductance anomaly coefficient, temperature anomaly coefficient and charge at the leakage point are normalized and comprehensively calculated to obtain the winding short-circuit coefficient.

5. A zero voltage vector multi-pulse belt speed re-casting method according to claim 4, characterized in that: The specific method for obtaining the winding short-circuit coefficient is: RX = WY - DY + DH; Among them, RX represents the winding short-circuit coefficient, WY represents the temperature anomaly coefficient, DY represents the inductance anomaly coefficient, and DH represents the charge at the leakage point.

6. A zero voltage vector multi-pulse belt speed re-throwing method according to claim 1, characterized in that: In step 2, the turn-to-turn short-circuit interval is set according to historical experimental data. If the winding short-circuit coefficient is less than the lower limit of the turn-to-turn short-circuit interval, the motor is judged to be normal. If the winding short-circuit coefficient is within the range of the winding short-circuit coefficient, it is judged to be a turn-to-turn short-circuit. If the winding short-circuit coefficient is greater than the upper limit of the turn-to-turn short-circuit interval, it is judged to be a phase-to-phase short-circuit.

7. A zero voltage vector multi-pulse belt speed re-throwing method according to claim 1, characterized in that: The specific steps of dynamically compensating the real-time speed and real-time position of the motor with turn-to-turn short circuit by using the adaptive pulse width dynamic compensation algorithm are as follows: The inductances of the three phases are compared respectively, and the phase with reduced inductance is judged as the fault phase according to the inductance phase difference method, and the voltage of this phase is increased in real time for the faulty phase. The current data is calculated by the variance method to obtain the current stability value, and the current data of the normal operation of the motor is summarized to obtain the current stability dynamic threshold. The current stability value is compared with the current stability dynamic threshold. If the current stability value is within the current stability dynamic threshold, stop increasing the voltage of this phase. If the current stability value is not within the current stability dynamic threshold, continue to increase the voltage of this phase until the current stability value is within the current stability dynamic threshold.

8. A zero voltage vector multi-pulse belt speed re-casting method according to claim 1, characterized in that: The specific method of obtaining the evolution value is as follows: Mathematical modeling is performed according to the characteristic of the accelerated decreasing trend of inductance to obtain an inductance trend model. The second-order derivative of the inductance trend model is taken. When the second-order derivative of the model is equal to zero, the evolution value is obtained.

9. A zero voltage vector multi-pulse belt speed re-casting method according to claim 1, characterized in that: In step three, a real-time comparison is made between the current inductance and the evolution value. If the current inductance is less than the evolution value, the predicted trend is turn-to-turn short circuit. If the current inductance is greater than or equal to the evolution value, the predicted trend is phase-to-phase short circuit.

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