Stationary Electronic Speed Measurement Test Method for Generators

Abstract

The present invention discloses a stationary electronic speed measurement method for a generator, which uses current sensors, voltage sensors and torque sensors to collect stator current, stator voltage and torque data of the generator in real time, and performs short-time Fourier transform (STFT) processing on the rotor current signal to obtain a preliminary speed estimation value; then, based on an adaptive algorithm combined with the electromagnetic characteristics of the motor, a more accurate speed estimation value is derived; finally, an adaptive weighted fusion algorithm is adopted to automatically adjust the weights of the two speed measurement methods according to the dynamic or steady-state working conditions of the generator to generate a final speed output; the combination measurement method overcomes the problem that traditional mechanical sensors are vulnerable to interference, and improves the response speed and measurement accuracy of sensorless speed measurement under dynamic working conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of generator control and measurement, and particularly to a static electronic speed measurement test method for generators. Background Art

[0002] During the operation of a generator, accurate speed measurement is of great significance for the state monitoring, fault diagnosis, and performance optimization of the control system of the generator; however, most traditional speed measurement methods rely on mechanical sensors, such as optical encoders or Hall sensors. The installation of these sensors is complex, costly, and vulnerable to interference from external environmental factors, resulting in a decrease in measurement accuracy; in addition, mechanical sensors also require regular maintenance and calibration, increasing the maintenance cost and downtime of the equipment; on the other hand, existing sensorless speed measurement methods usually have difficulty providing sufficient measurement accuracy under dynamic operating conditions, especially in non-steady-state situations such as rapid load changes or generator startup and shutdown, where traditional methods are prone to problems such as large measurement errors or insufficient response speed.

[0003] Based on this, there is a need for a static electronic speed measurement test method for generators. Summary of the Invention

[0004] To achieve the above object, the present invention provides the following solution: A static electronic speed measurement test method for a generator, comprising the following steps:

[0005] Step 1: Real-time collect stator current , rotor current , stator voltage and torque electromagnetic parameters from the stator and rotor electrical ports of the generator through high-precision sensors. The acquisition of the electromagnetic parameters uses high-precision current sensors, voltage sensors, and torque sensors. These three sensors are all connected to an embedded control system, continuously monitor and real-time collect electromagnetic signals during the operation of the generator, perform short-time Fourier transform (STFT) processing on the collected rotor current signal to obtain the frequency spectrum diagram of the rotor current signal , and extract the main frequency component from it through frequency spectrum analysis. The main frequency component is proportional to the generator speed;

[0006] Calculate the preliminary speed estimation value of the generator according to the formula ;

[0007] Wherein, is the speed estimation value, with the unit of revolutions per minute (RPM), is the main frequency component extracted from the rotor current spectrum, is the number of pole pairs of the generator;

[0008] Step 2: On the basis of the preliminary rotational speed estimation completed in Step 1, simultaneously perform adaptive motor data acquisition, and collect the stator current of the generator in real time , stator voltage and torque data, and transmit them to the embedded control system for real-time calculation, and deduce the rotational speed using calculation;

[0009] wherein, is the adaptive rotational speed estimation value, with the unit of revolutions per minute (RPM), is the electromagnetic constant of the generator, and are the stator voltage and stator current collected in real time respectively, is the electromagnetic torque of the generator, and automatically adjusts the electromagnetic constant according to the collected stator voltage, stator current and torque data combined with the real-time operating state under different loads and working conditions;

[0010] Step 3: After calculating the sensorless rotational speed estimation value and the adaptive rotational speed estimation value in Step 1 and Step 2 respectively, according to the sensorless speed measurement calculation result and the adaptive rotational speed calculation result , adopt the adaptive weighted fusion algorithm to comprehensively process the measurement results of the two, and the adaptive weighted fusion algorithm dynamically adjusts the weights and of the two rotational speed measurement results according to the current working state of the generator, and generate the final accurate rotational speed output , and the fusion formula is: ; wherein, the weight , under the dynamic working conditions of the generator, , preferentially increase the weight of the sensorless rotational speed estimation result ; while under the steady-state working conditions, , increase the weight of the adaptive rotational speed calculation result , and the finally generated rotational speed is output as the real-time rotational speed data of the generator.

[0011] Further preferably, the short-time Fourier transform (STFT) processing in Step 1 includes processing the collected rotor current The signal is subjected to multi-stage preprocessing. The high-frequency and low-frequency noises in the signal are suppressed by a digital filter to ensure the stability and continuity of the signal. A time-frequency analysis window is selected, and the window length is dynamically adjusted according to the operating speed and frequency range of the generator, enabling the accurate extraction of the main frequency component of the rotor current under different working conditions. , during the process of extracting the frequency components, for the spectrogram the main peaks are identified, and thresholds are set according to the preset frequency range, making the extracted main frequency component highly consistent with the actual generator speed.

[0012] Further preferably, the electromagnetic parameter acquisition in step 1 also includes the acquisition of the stator phase voltage and phase current of the generator. The data of the phase voltage and phase current are used to supplement the stator voltage and stator current information, improving the extraction of frequency components in sensorless speed measurement.

[0013] Further preferably, the implementation method of the adaptive motor data acquisition in step 2 includes:

[0014] The stator current and stator voltage of the generator are acquired in real time, and the electromagnetic torque data of the generator is obtained by using a torque sensor. The torque sensor adopts a dynamic measurement mode and reflects the change of torque in real time according to the load change. All the acquired electromagnetic data is used to calculate and adjust the value of the electromagnetic constant in real time through an embedded control system.

[0015] Further preferably, the acquisition of the torque is carried out by a high-precision torque sensor, and the torque sensor provides torque data in real time under different load conditions; the signal output of the torque sensor is corrected by an error compensation algorithm.

[0016] Further preferably, the adaptive weighted fusion algorithm in step 3 is realized by dynamically adjusting the weight coefficients and . The weight values are adjusted according to the load volatility and torque change rate monitored in real time. Under dynamic working conditions, the weight of the sensorless speed estimation result is preferentially increased, while under steady-state working conditions, the weight of the adaptive speed estimation result is increased.

[0017] Further preferably, when adjusting the weight coefficient, the operating environment data of the generator temperature, humidity, load status, and mechanical vibration are collected and analyzed in real time through an embedded sensor, and are fused with the electromagnetic parameters of the generator. The embedded control system dynamically adjusts the sensorless speed measurement result according to the fluctuations of the environmental parameters. and the adaptive measurement result of the weight coefficient.

[0018] Further preferably, the method continuously monitors the operating state of the generator through a monitoring module, and the monitoring module is based on the stator current 、rotor current 、stator voltage and torque to calculate the efficiency and load of the generator based on the real-time data.

[0019] According to the specific embodiments provided by the present invention, the following technical effects are disclosed:

[0020] The present invention performs spectral analysis on the electrical parameters of the generator to extract the frequency components related to the rotational speed, so as to achieve non-contact rotational speed measurement; the adaptive speed measurement dynamically derives the rotational speed by collecting the stator current, stator voltage, and electromagnetic torque data of the generator in real time, and combines the electromagnetic characteristic model, and automatically adjusts the parameters according to the operating conditions to improve the measurement accuracy. The adaptive weighted fusion algorithm automatically adjusts the weights of the two speed measurement methods according to the dynamic or steady-state conditions of the generator in the two test methods, and can provide high-precision rotational speed measurement under different load conditions;

[0021] In addition, the present invention monitors the environmental operating state of the generator through an embedded sensor, optimizes the weight adjustment process, and ensures the stability of the measurement under complex and changeable environments; the combined measurement method overcomes the problem that traditional mechanical sensors are vulnerable to interference, and improves the response speed and measurement accuracy of sensorless speed measurement under dynamic conditions. Description of the Drawings

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0023] Figure 1 is the flowchart of the steps of the present invention. Detailed Embodiments

[0024] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with 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.

[0025] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. Embodiment

[0026] As Figure 1 shown, the stationary electronic speed measurement test method for a generator in this embodiment includes the following steps:

[0027] Step 1: Use multiple high-precision sensors to measure the electromagnetic parameters of the generator. The sensors are distributed at the stator and rotor ports of the generator for collecting stator current , rotor current , stator voltage and the electromagnetic torque of the generator . The collection of stator current and stator voltage is completed through the current sensor and voltage sensor at the stator end. The sensors used for collection have extremely high sensitivity and maintain linear output in different current ranges, ensuring the accuracy and real-time nature of data collection. The measurement of rotor current requires the use of a special non-contact current sensor to avoid interfering with the rotating part of the generator, and the measurement of electromagnetic torque is completed by a high-precision torque sensor installed on the rotating shaft, which can accurately reflect the torque change of the generator under different load conditions; the sensors are connected to the embedded control system through a high-speed data acquisition module. The system monitors and collects electromagnetic signals in real time during the operation of the generator. The collection frequency is related to the operating state of the generator. When running at high speed, the collection frequency will increase accordingly to ensure a rapid response to speed changes; while during stable operation, the sampling frequency can be appropriately reduced to reduce data redundancy and improve processing efficiency. Through the arrangement of these sensors, accurate electromagnetic parameter data can be obtained in various environments. When these electromagnetic parameters are collected, especially the rotor current signal undergoes preliminary filtering processing. A digital filter is used to suppress high-frequency noise and low-frequency interference in the signal to ensure the stability and continuity of the signal. The noise mainly comes from electromagnetic interference, environmental factors, and mechanical noise during the operation of the generator. The purpose of eliminating noise is to obtain a clean and accurate current signal. After filtering processing, the rotor current The signal will be processed by Short-Time Fourier Transform (STFT). STFT is a commonly used time-frequency analysis tool. By dividing the signal into several short-time windows and performing Fourier transform on the signals within these windows respectively, the time-domain and frequency-domain information of the signal can be obtained simultaneously. In the present invention, the time-frequency analysis window of STFT will be dynamically adjusted according to the operating speed and frequency range of the generator. The higher the operating speed of the generator, the shorter the length of the analysis window, so as to obtain higher time resolution in frequency analysis; while when the operating speed of the generator is low, a longer analysis window is selected to improve the frequency resolution. When performing STFT processing, the rotor current signal is divided into multiple short-time segments, and the length of each segment is dynamically determined according to the real-time operating state of the generator. Fourier transform is performed on the signal within each segment to generate the corresponding spectrogram , and the spectrogram shows the frequency distribution of the signal in different time periods. By analyzing the spectrogram, the most prominent main frequency component can be extracted ;

[0028] After extracting the main frequency component of the rotor current , the initial speed of the generator is estimated by the following formula:

[0029]

[0030] The number of pole pairs of the generator is a known constant. By calculating the main frequency , the estimated value of the generator speed is obtained .

[0031] Step 2: In this step, the stator current and stator voltage of the generator are core electromagnetic parameters used to derive the estimated speed value . In addition, a dynamic high-precision torque sensor installed on the rotating shaft is used to monitor the torque of the generator in real time. The torque sensor uses a non-contact measurement method and does not affect the normal operation of the generator. The torque sensor can provide real-time torque data under different load conditions, reflecting the influence of the load on the generator. When the load of the generator is increasing or decreasing, the torque sensor can accurately capture the torque fluctuations and transmit the data to the embedded control system for processing; after collecting the stator current , stator voltage and torque , an adaptive speed estimation is performed in combination with the electromagnetic characteristic model of the generator. The electromagnetic characteristic model is based on electromagnetic parameters, and the estimated speed value of the generator is derived by real-time monitoring of these parameters. The estimated speed value is calculated by the following formula:

[0032]

[0033] Under static conditions, is regarded as a constant. During the actual operation process, especially when the load changes, it will change dynamically due to factors such as the operating state of the generator, temperature change, and electromagnetic field distribution. To ensure the accuracy of measurement, the electromagnetic constant must be adjusted in real time , to adapt to different loads and working conditions. By dynamically adjusting the value, it can change with the change of the operating state of the generator. The adjustment of the electromagnetic constant is automatically completed by the embedded control system. The system automatically adjusts the numerical value according to the current, voltage, and torque data collected in real time and combined with the operating state of the generator. By adjustment, it is ensured that the rotational speed value can be accurately estimated under different loads, rotational speeds, and operating environments ;

[0034] The signal output by the torque sensor is corrected through the error compensation algorithm. Since the measurement environment of the torque sensor is affected by external factors such as mechanical vibration, environmental temperature change, and electromagnetic interference, the measured value is prone to certain deviations. The embedded controller monitors the external influencing factors in real time and corrects the measured value through the preset error compensation model. For example, when the environmental temperature rises, the output of the torque sensor is affected by thermal noise, and the system can correct the sensor signal according to the real-time temperature data; similarly, when the generator is affected by electromagnetic interference, the system can eliminate the interference signal through the noise filtering algorithm. During the operation of the generator, it can reflect the fluctuation of the rotational speed in real time according to the change of the load. Especially when the load of the generator suddenly increases or decreases, it can quickly respond to this change through the adaptive rotational speed estimation. Since the electromagnetic constant is dynamically adjusted according to the real-time working conditions, by quickly correcting the value, it is ensured that the result of the rotational speed estimation is not affected by the load fluctuation.

[0035] Step 3: In this step, through the comprehensive processing of sensorless rotational speed estimation and adaptive rotational speed estimation based on the built-in data of the motor , high-precision rotational speed measurement under complex working conditions is realized. The present invention adopts an adaptive weighted fusion algorithm to dynamically adjust the weight coefficients of the sensorless rotational speed estimation value and the adaptive rotational speed estimation value and , so that the final rotational speed estimation value can not only quickly respond to the change of the working condition, but also provide accurate measurement results under stable operating conditions;

[0036] Sensorless Speed Estimation The speed is derived by analyzing the current frequency components of the generator and has the ability to respond quickly under dynamic conditions such as generator acceleration, deceleration, or load fluctuations. Under these dynamic conditions, in order to be able to promptly capture the rapid changes in the generator speed, the sensorless speed estimation value will be preferentially increased of the weight , at this time the weighted fusion algorithm automatically adjusts to make it dominant and ensure that the speed measurement can promptly respond to the changes in the generator operating conditions; the formula is as follows:

[0037]

[0038] Among them, , when the generator operating conditions change drastically, the weight increases, correspondingly decreases, in order to improve the dynamic response ability. Under steady-state operating conditions, the load and operating environment of the generator are relatively stable, and it will rely more on the adaptive speed estimation , because the adaptive speed estimation calculates the results through the motor stator current , stator voltage , and torque data, and the calculated results have high measurement accuracy. Therefore, under the condition that the generator is running relatively smoothly, the adaptive algorithm can provide extremely accurate speed estimation values. At this time, the weight occupies a larger proportion in the fusion algorithm to ensure that the system obtains high-precision speed measurement results under steady-state operating conditions. By using an embedded sensor to monitor the environmental operating state of the generator and collect external parameters such as temperature, humidity, load fluctuations, and mechanical vibration, since the environmental data will affect the electromagnetic characteristics and operating efficiency of the generator, the system combines these environmental factors to dynamically adjust the weights and of speed estimation;

[0039] For example, when the temperature or load suddenly changes, the system will temporarily increase the weight of the sensorless speed estimation to ensure that it can still quickly respond to the generator state when the environmental conditions change; while when the temperature and load are stable, it will increase the weight of the adaptive speed estimation to improve the measurement accuracy. The fusion result is the final speed output, which is output to the local display device for the operator to monitor in real time. In addition, the system also transmits this data to the remote monitoring platform through the remote communication interface. The remote monitoring system can analyze the operating state of the generator based on the received real-time speed data.

[0040] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0041] In this article, specific examples are used to elaborate on the principles and implementation manners of the present invention. The descriptions of the above embodiments are only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A static electronic speed measurement test method for a generator, characterized in that: The following steps are involved: Step 1: Use high-precision sensors to collect the stator current I from the stator and rotor electrical ports of the generator in real time s , rotor current I r , stator voltage V s The electromagnetic parameters of the electromagnetic parameters are collected by using high-precision current sensors, voltage sensors and torque sensors. These three sensors are connected to the embedded control system to continuously monitor and collect electromagnetic signals in real time during the operation of the generator. r The signal is processed by short-time Fourier transform (STFT) to obtain the spectrum of the rotor current signal F(I r ,t,f), and extract the main frequency component f through spectrum analysis r , the main frequency component f r Proportional to the generator speed; According to the formula Calculate the initial estimated value n1 of the generator speed; Where n1 is the initial speed estimate in revolutions per minute (RPM), and f r is the main frequency component f extracted by short-time Fourier transform STFT r , p is the number of pole pairs of the generator. The number of pole pairs p of the generator is a known constant. By calculating the main frequency component f r Obtain a preliminary estimated value n1 of the generator speed; Step 2: Based on the preliminary speed estimation completed in step 1, adaptive motor data acquisition is performed simultaneously to collect the stator current I of the generator in real time. s , stator voltage V s The torque T data is transmitted to the embedded control system for real-time calculation, and the adaptive speed estimation value n2 is derived through the electromagnetic characteristic model of the generator. Calculate the adaptive speed estimate n2; Among them, K is the electromagnetic constant of the generator, V S and I s are the stator voltage and stator current collected in real time, T is the electromagnetic torque of the generator. According to the collected stator voltage, stator current and torque data combined with the real-time operating status, the electromagnetic constant K is automatically adjusted under different loads and working conditions; Step 3: After calculating the sensorless preliminary speed estimation value n1 and the adaptive speed estimation value n2 in step 1 and step 2 respectively, the measurement results of the two are comprehensively processed using an adaptive weighted fusion algorithm. The adaptive weighted fusion algorithm dynamically adjusts the weights w1 and w2 of the two speed measurement results according to the current working state of the generator to generate the final generated speed n fin , the fusion formula is: n fin =w1·n1+w2·n2; where weight w1+w2=1; Under the dynamic condition of the generator, the weight w1 of the sensorless preliminary speed estimate n1 is increased first, while under the steady-state condition, the weight w2 of the adaptive speed estimate n2 is increased. The final generated speed n fin As the real-time speed data output of the generator.

2. The static electronic speed measurement test method for a generator according to claim 1, characterized in that: The short-time Fourier transform (STFT) processing in step 1 includes the acquisition of the rotor current I r (t) Preprocess the signal and suppress the high-frequency and low-frequency noise in the signal through digital filters to ensure the stability and continuity of the signal; select the time-frequency analysis window, and the window length is dynamically adjusted according to the operating speed and frequency range of the generator to accurately extract the main frequency component f of the rotor current under different working conditions. r , in extracting the main frequency component f r In the process of r ,t,f), and set the threshold according to the preset frequency range so that the extracted main frequency component f r It is highly consistent with the actual generator speed.

3. The static electronic speed measurement test method for a generator according to claim 1, characterized in that: The electromagnetic parameter collection in step 1 also includes the collection of the stator phase voltage and phase current of the generator, and the data of the phase voltage and phase current are used to supplement the stator voltage V s and stator current I s Information, improve the main frequency component f in sensorless speed measurement r Extraction.

4. The static electronic speed measurement test method for a generator according to claim 1, characterized in that: The adaptive motor data acquisition in step 2 is implemented by: Real-time acquisition of the generator's stator current I s and stator voltage V s The torque sensor is used to obtain the electromagnetic torque T data of the generator. The torque sensor adopts a dynamic measurement mode to reflect the change of torque in real time according to the load change. All the collected electromagnetic data are calculated in real time by the embedded control system to adjust the value of the electromagnetic constant K.

5. The static electronic speed measurement test method for a generator according to claim 1, characterized in that: The torque T is collected by a high-precision torque sensor, which provides torque data in real time under different load conditions; the signal output of the torque sensor is corrected by an error compensation algorithm.

6. The static electronic speed measurement test method for a generator according to claim 1, characterized in that: The adaptive weighted fusion algorithm in step 3 is implemented by dynamically adjusting the weight coefficient w1 and the weight coefficient w2. The weight value is adjusted according to the load fluctuation rate and torque change rate monitored in real time. Under dynamic conditions, the weight coefficient w1 of the sensorless preliminary speed estimate n1 is increased preferentially, while under steady-state conditions, the weight coefficient w2 of the adaptive speed estimate n2 is increased.

7. The static electronic speed measurement test method for a generator according to claim 1, characterized in that: When adjusting the weight coefficient w1 and the weight coefficient w2, the operating environment data of the generator temperature, humidity, load status and mechanical vibration are collected and analyzed in real time through embedded sensors, and fused with the electromagnetic parameters of the generator. The embedded control system dynamically adjusts the weight coefficient w1 and the weight coefficient w2 of the sensorless preliminary speed estimation value n1 and the adaptive speed estimation value n2 according to the fluctuations of the environmental parameters.

8. The static electronic speed measurement test method for a generator according to claim 1, characterized in that: The method continuously monitors the operating state of the generator through a monitoring module, and the monitoring module is based on the stator current I s , rotor current I r , stator voltage V s Real-time data of torque T is used to calculate the efficiency and load of the generator.

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