Multi-degree-of-freedom resonant excitation motor dynamic vibration test system and test method

Abstract

The invention relates to the technical field of motor fault diagnosis, and discloses a multi-degree-of-freedom resonant excitation motor dynamic vibration test system and a test method, the system injects a specific harmonic current into a motor through closed-loop control and calculation and a high-bandwidth harmonic injection driver, so that the actual vibration of the tested motor tracks a preset target vibration profile in real time. In the testing process, the cross-spectral density of multi-point vibration signals is analyzed, and a transmission path and a collection area of vibration energy in a motor structure are calculated; and meanwhile, the electromagnetic impedance and the mechanical impedance of the motor are identified and decoupled on line by superposing a broadband disturbance signal in the driving current. In combination with energy flow analysis and an impedance decoupling result, the method can accurately position a vibration abnormal position, clearly causes whether a fault source is from mechanical structure characteristic change or electromagnetic part performance change from a physical level, and realizes deep and accurate diagnosis of the dynamic characteristics of the motor.

Description

Technical Field

[0001] This invention relates to the field of motor fault diagnosis technology, specifically to a dynamic vibration testing system and method for multi-degree-of-freedom resonant excitation motors. Background Technology

[0002] As a core power equipment in industrial production, the stability and reliability of motor operation are of paramount importance. Vibration analysis is a key technical means to assess the health status of motors and implement predictive maintenance. By monitoring the vibration signals generated during motor operation, potential mechanical or electromagnetic faults can be detected, avoiding losses caused by unplanned downtime.

[0003] Existing motor vibration analysis techniques typically involve installing accelerometers at specific locations on the motor housing to collect vibration signals from the motor during its natural operation. Then, tools such as spectrum analysis are used to convert the time-domain vibration signals to the frequency domain. By observing whether there are characteristic frequencies on the spectrum related to bearing failure, rotor imbalance, or misalignment, it is possible to determine whether there are any abnormalities in the motor.

[0004] However, this traditional passive measurement and analysis method has its inherent limitations. Since it only collects the vibrations naturally generated by the motor under specific operating conditions, its diagnostic capability is limited by whether the operating conditions can fully excite the fault characteristics. For early and weak fault signals, the vibration energy generated may be completely drowned out by normal operating noise, making it impossible to detect effectively. In addition, this method cannot test the dynamic response of the motor at a specific frequency as needed and repeatably, and lacks the ability to actively excite and detect the system.

[0005] Furthermore, even if an abnormal vibration frequency is identified through spectrum analysis, existing technology only provides a superficial identification of the vibration symptoms. It can reveal what frequency the vibration is, but it cannot provide effective information about the source of the vibration energy inside the motor or the specific transmission path. This makes the fault location process like the blind men and the elephant, making it difficult to accurately pinpoint the point of convergence of vibration energy or the weak point in the structure.

[0006] More importantly, existing vibration analysis techniques have significant ambiguity in attributing the root cause of faults. Motor vibration is a typical electromechanical coupling phenomenon. A specific vibration characteristic may originate from a purely mechanical structural problem (such as bearing wear), or from an electromagnetic problem (such as electromagnetic force imbalance caused by short circuits between winding turns), or even from the combined effect of both. Traditional vibration spectrum analysis methods have difficulty in clearly decoupling and distinguishing these two completely different fault sources, leading to uncertainty in diagnostic conclusions. This may result in incorrect maintenance decisions, such as mistakenly replacing healthy mechanical parts while ignoring the fundamental electromagnetic problem. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a dynamic vibration testing system and method for multi-degree-of-freedom resonant excitation motors. This solves the problems of existing motor vibration analysis technologies, which rely on passive measurement and are unable to actively excite and identify early, subtle faults, and are unable to effectively decouple and accurately locate the root causes of electromechanical coupling faults.

[0008] The first aspect of this invention provides a dynamic vibration testing system for a multi-degree-of-freedom resonant excitation motor, comprising: A vibration sensor array is configured at a preset position on the motor under test to collect the actual vibration signal of the motor under test in real time. A high-bandwidth harmonic injection driver, electrically connected to the motor under test, is used to inject a drive current containing fundamental current and harmonic current into the motor under test. The central real-time control and analysis host is connected to the vibration sensor array and the high-bandwidth harmonic injection driver signal.

[0009] The central real-time control and analysis host includes: A vibration state observer is used to receive the actual vibration signals collected by the vibration sensor array; The controller is used to compare the actual vibration signal received by the vibration state observer with the preset target vibration profile, and to calculate and generate control commands in real time through a closed-loop control algorithm. The harmonic calculation module is used to calculate the amplitude, frequency, and phase of the harmonic current that the high-bandwidth harmonic injection driver needs to inject into the motor under test, based on the control instructions generated by the controller. The instruction output module is used to send the harmonic current determined by the harmonic calculation module, together with the fundamental current, to the high-bandwidth harmonic injection driver, so as to control the high-bandwidth harmonic injection driver to inject the driving current containing the fundamental current and the harmonic current into the motor under test, thereby driving the actual vibration signal of the motor under test to track the target vibration profile. The diagnostic analysis module is used to generate a diagnostic report on the dynamic characteristics of the motor under test based on the actual vibration signal collected by the vibration sensor array and the harmonic current calculated by the harmonic calculation module after the test.

[0010] In one specific embodiment, the controller calculates the vibration error based on the preset target vibration profile and the actual vibration signal collected by the vibration sensor array. Furthermore, the harmonic calculation module, based on the vibration error and according to the electromagnetic mechanical transfer function model of the motor under test, calculates inversely the amplitude, frequency, and phase of the harmonic current required to compensate for the vibration error, and generates the corresponding control command.

[0011] Preferably, the central real-time control and analysis host further includes a vibration energy flow analysis module. Based on the cross-spectral density relationship between multiple actual vibration signals collected by the vibration sensor array, the vibration energy flow analysis module calculates the transmission path and distribution of vibration energy within the tested motor structure in real time. Specifically, for vibration signals X collected at any two points i and j in the vibration sensor array... i The cross-spectral density S of X(t) and X(t) is... i (f) can be calculated using the following formula: S i (f)=E[X i [(f)×X(f)]; Where f is the frequency; E is the expectation operator; X i X(f) and X(f) are respectively X i Fourier transforms of X(t) and X(t); X(f) is the Fourier transform of X(t) and X(t); i (f) conjugate; S i (f) represents the cross-spectral density. By analyzing the phase information of the cross-spectral density between points, the direction of vibrational energy transmission can be determined.

[0012] Furthermore, the harmonic calculation module is also used to adaptively adjust the phase of the harmonic current based on the calculation results of the vibration energy flow analysis module and in comparison with the preset excitation focus area, so as to realize the active control of the transmission path of the vibration energy and make the vibration energy converge in the excitation focus area.

[0013] In one specific embodiment, the central real-time control and analysis host further includes an online impedance identification module. The online impedance identification module is used to identify and decouple the electromagnetic impedance and mechanical impedance of the motor under test in real time during the execution of the closed-loop control algorithm.

[0014] Preferably, the online impedance identification module achieves identification and decoupling in the following way: controlling the high-bandwidth harmonic injection driver to inject a preset broadband disturbance current simultaneously with the driving current; and simultaneously calculating the electromagnetic impedance and mechanical impedance by analyzing the weak vibration response and electrical response caused by the broadband disturbance current in the corresponding frequency band. The mechanical impedance Z(ω) and electromagnetic impedance Z... e (ω) can be decoupled in the frequency domain ω by the following relationship: V(ω)=Z(ω)×F(ω)+T em (ω)×I(ω); U(ω)=T me (ω)×V(ω)+Z e (ω)×I(ω); Where U(ω) and I(ω) are the motor terminal voltage and current; V(ω) is the vibration velocity; F(ω) is the non-electromagnetic external force (which can be considered as 0 under pure electromagnetic excitation); T em (ω) and T me Z(ω) is the electromechanical coupling transfer function; Z(ω) is the mechanical impedance; Z e Z(ω) is the electromagnetic impedance. By injecting a broadband perturbation current with a known spectrum and measuring the resulting voltage and vibration response, this system of equations can be solved to obtain Z(ω) and Z0. e (ω).

[0015] Furthermore, the diagnostic analysis module is also used to perform physical root cause analysis on the changes in the dynamic characteristics of the tested motor based on the changes in electromagnetic impedance and mechanical impedance decoupled from the online impedance identification module over time or under operating conditions, so as to distinguish whether the changes are caused by changes in the performance of electromagnetic components or changes in mechanical structural characteristics.

[0016] In one specific embodiment, the electromagnetic mechanical transfer function model is an inverse transfer function model, which allows the harmonic calculation module to directly calculate the required harmonic current from the vibration error using the inverse transfer function model.

[0017] In one specific embodiment, the diagnostic report generated by the diagnostic analysis module includes at least one or more of the following: an assessment of the actual vibration response accuracy of the motor under test when tracking the target vibration profile; a spectral distribution analysis of the harmonic current required to maintain the target vibration profile; a visualization of the vibration energy accumulation region generated based on the calculation results of the vibration energy flow analysis module; and a physical root cause attribution analysis conclusion generated based on the calculation results of the online impedance identification module.

[0018] The second aspect of the present invention provides a method for dynamic vibration testing of a multi-degree-of-freedom resonant excitation motor, comprising the following steps: S1, setting the target vibration profile of the motor under test; S2. The actual vibration signal of the motor under test is acquired in real time through a vibration sensor array; S3. Compare the actual vibration signal with the target vibration profile and calculate the vibration error; S4. Based on the vibration error, the harmonic current required to compensate for the vibration error is calculated in real time using a closed-loop control algorithm. S5. Control the high-bandwidth harmonic injection driver to combine the harmonic current and the fundamental current into a driving current and inject it into the motor under test, so as to drive the actual vibration signal of the motor under test to track the target vibration profile in real time. S6. After the test, based on the cross-spectral density relationship between the actual vibration signals collected during the test, identify the vibration energy accumulation area in the structure, and perform physical root cause analysis based on the changes in the electromagnetic impedance and mechanical impedance of the tested motor identified online, and generate a diagnostic report.

[0019] In one specific embodiment, while the method is being executed in step S4, it also includes: controlling the high-bandwidth harmonic injection driver to inject a preset broadband disturbance current, and identifying and decoupling the electromagnetic impedance and mechanical impedance of the motor under test online based on the vibration response and electrical response caused by the disturbance current, so as to be used for physical root cause analysis in step S6.

[0020] This invention provides a dynamic vibration testing system and method for a multi-degree-of-freedom resonant excitation motor. It offers the following advantages: 1. This invention employs a closed-loop control algorithm to compare the actual vibration signal collected by the vibration sensor array with the preset target vibration profile in real time, and calculates the required injected harmonic current based on the difference. This scheme can drive the motor under test to accurately track and reproduce any complex target vibration mode under actual load operation, thereby simulating specific vibration fault modes or actively exciting specific structural resonance points for testing.

[0021] 2. This invention, by setting up an online impedance identification module, injects a broadband disturbance current during closed-loop control and identifies and decouples the electromagnetic impedance and mechanical impedance of the motor under test in real time. When the dynamic characteristics of the motor change, this invention can clearly distinguish the root cause of the change as either electromagnetic component performance degradation or mechanical structural characteristic change by tracking whether the change is due to electromagnetic impedance or mechanical impedance, thus providing a clear physical basis for fault diagnosis.

[0022] 3. This invention combines a vibration energy flow analysis module and an online impedance identification module. The diagnostic analysis module correlates the identified vibration energy accumulation area (transmission path and endpoint) with the conclusions of the physical root cause analysis. This allows the final diagnostic report to not only indicate the physical nature of the fault (electromagnetic or mechanical) but also associate it with the specific physical location on the motor structure, achieving precise location from the root cause of the problem to the affected area. Attached Figure Description

[0023] Figure 1 This is an overall architecture diagram of the multi-degree-of-freedom resonant excitation motor dynamic vibration testing system of the present invention; Figure 2 This is a flowchart of the dynamic vibration test method for a multi-degree-of-freedom resonant excitation motor according to the present invention. Detailed Implementation

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] See attached document Figure 1 , Figure 1 This is a structural block diagram of a dynamic vibration testing system for a multi-degree-of-freedom resonant excitation motor according to an embodiment of the present invention. The present invention provides a dynamic vibration testing system for a multi-degree-of-freedom resonant excitation motor, which may include: a vibration sensor array 10, a high-bandwidth harmonic injection driver 20, and a central real-time control and analysis host 30.

[0026] The vibration sensor array 10 is configured on the housing of the motor under test or other preset positions to collect the actual vibration signals of the motor under test in multiple degrees of freedom in real time and transmit the signals to the central real-time control and analysis host 30. The high-bandwidth harmonic injection driver 20 has its output terminal electrically connected to the stator winding of the motor under test and its control input terminal connected to the central real-time control and analysis host 30 to generate and inject drive current into the motor under test according to the instructions sent by the host.

[0027] The central real-time control and analysis host 30 is the core control and calculation unit for executing the test method of the present invention. In a specific embodiment, the host may include: a vibration state observer 31, a controller 32, a harmonic calculation module 33, an instruction output module 34, and a diagnostic analysis module 35.

[0028] During system operation, the vibration state observer 31 receives multiple actual vibration signals from the vibration sensor array 10. The controller 32 receives the actual vibration signals from the vibration state observer 31 and compares them in real time with a preset target vibration profile. Using a closed-loop control algorithm, it calculates the vibration error between the two. The harmonic calculation module 33 receives control commands from the controller 32, which contain vibration error information. Based on this vibration error, the harmonic calculation module 33 calculates the specific parameters of one or more sets of harmonic currents required to compensate for the error, including the amplitude, frequency, and phase of each harmonic.

[0029] The instruction output module 34 integrates the harmonic current parameters calculated by the harmonic calculation module 33 and combines them with the fundamental current parameters used to maintain the normal operation of the motor under test to generate the final drive current command, and sends it to the high-bandwidth harmonic injection driver 20.

[0030] The high-bandwidth harmonic injection driver 20 synthesizes the total drive current i based on the received drive current command. total (t), and inject it into the motor under test. The total drive current consists of the fundamental current i base (t) and harmonic current i h It is composed of superpositions of (t), and its mathematical form can be expressed as: i total (t)=i base (t)+i h (t); Among them, i base (t) is the sinusoidal fundamental current used to maintain the motor at a specific speed and load; i total (t) represents the total drive current; i h (t) represents the harmonic current. The harmonic current i h (t) is dynamically calculated and generated to track the vibration profile of the target. It can be a superposition of multiple sine waves with different frequencies and phases, and its general form is: Where A, ω and These are the amplitude, angular frequency, and phase of the k-th injected harmonic, respectively, and these parameters are determined in real time by the harmonic calculation module 33; i h (t) represents the harmonic current; t represents time. By precisely controlling this harmonic current, the system can drive the actual vibration signal of the motor under test to track the preset target vibration profile in real time; ∑ represents the sum of all sinusoidal components on the right (from k=1 to n).

[0031] After the test, the diagnostic analysis module 35 performs offline analysis based on the actual vibration signal data recorded by the host during the entire closed-loop control process and the harmonic current data calculated and output by the harmonic calculation module 33, and generates a diagnostic report on the dynamic characteristics of the motor under test.

[0032] See attached document Figure 1 , Figure 1 This is a schematic diagram of the internal functional modules of a central real-time control and analysis host 30 according to an embodiment of the present invention. The modules within the host 30 work together to achieve closed-loop tracking control of the dynamic vibration of the motor under test.

[0033] The vibration state observer 31 receives and processes the raw vibration signals from the vibration sensor array 10. In one specific embodiment, this module integrates a signal conditioning circuit and a multi-channel high-speed analog-to-digital converter. It receives multiple analog vibration signals, which are first filtered by an anti-aliasing filter and then converted into a digital signal sequence by the analog-to-digital converter. To ensure time alignment of the multiple signals, the module also includes a data buffer and a timestamp generation unit, which appends a unified timestamp to each set of synchronously acquired data points, ultimately outputting an actual vibration state vector V composed of multi-dimensional time series data that accurately reflects the current vibration state of the tested motor. actual (t), and transmit it to controller 32.

[0034] Controller 32 is the core execution unit of the closed-loop control algorithm. It receives the actual vibration state vector V from vibration state observer 31. actual (t), and read the preset target vibration profile V from a storage unit. target (t). The target vibration profile is a vector composed of multidimensional time-series data, defining the vibration pattern of the motor under test at each sensor measurement point during the test. The controller 32 calculates the vibration error vector V in real time by performing vector subtraction. error (t)=V target (t)-V actual (t). Subsequently, the controller 32 will use the vibration error vector V error (t) is used as input, and one or more proportional-integral-derivative control algorithms are used to calculate the control action required to eliminate this error, and a correction instruction containing the control action information is generated and sent to the harmonic calculation module 33.

[0035] The function of the harmonic calculation module 33 is to calculate, in reverse, the specific parameters of the electromagnetic excitation, i.e., the harmonic current, required to achieve the correction amount, based on the correction command issued by the controller 32. This module internally stores or constructs in real-time an inverse model H of the electromagnetic-mechanical transfer function of the motor under test. -1 The inverse model of the electromagnetic mechanical transfer function describes the mathematical relationship between vibration on the motor surface and harmonic current in the stator windings. When the vibration error vector V is received... error (t) After that, the harmonic calculation module 33 uses the inverse model of the electromagnetic mechanical transfer function to perform calculations, I h (t)=H -1 (V error (t)) thus directly calculates the amplitude A, frequency ω, and phase of one or more sets of harmonic currents required to compensate for this vibration error. The calculation results are organized into a structured set of harmonic parameters.

[0036] The function of the command output module 34 is to synthesize the complete current command required for the final driver. This module receives the harmonic parameter set from the harmonic calculation module 33 and obtains the fundamental current parameters (fundamental amplitude and frequency) required for the current motor operation from an operating condition setting unit. Based on all received parameters, the command output module 34 generates the fundamental current i through numerical calculation. base (t) and total harmonic current i h The module then superimposes these two digital waveforms to form the digital waveform i of the total drive current. total (t), and convert it into a control signal format that the high-bandwidth harmonic injection driver 20 can receive, such as a pulse width modulation signal sequence, and continuously output it to the driver 20.

[0037] The diagnostic analysis module 35 is used for recording and preliminary analysis of test data. Throughout the closed-loop control test, this module synchronously records the actual vibration state vector V output by the vibration state observer 31. actual The data includes a (t) sequence and a harmonic parameter set sequence generated by the harmonic calculation module 33. After the test, this module can process the recorded data, for example, by calculating the vibration error vector V. error The overall accuracy of vibration tracking can be assessed by the root mean square value of (t), or by performing spectral analysis on the injected harmonic current to identify the frequency points where continuous energy injection is required to maintain the target vibration profile. These frequency points typically correspond to the mechanical resonant frequencies of the system.

[0038] To achieve in-depth diagnosis of the dynamic characteristics of the tested motor, in a preferred embodiment of the present invention, referring to the attached... Figure 1 The central real-time control and analysis host 30 further includes a vibration energy flow analysis module 36 and an online impedance identification module 37.

[0039] The vibration energy flow analysis module 36 is used to determine the transmission path and distribution of vibration energy within the structure of the motor under test. The input to this module is a sequence of multiple digital vibration signals, time-synchronized and provided by the vibration state observer 31. Its core calculations are based on the vibration signals X acquired at any two points i and j. i Cross-spectral density analysis was performed on X(t) and X(t). First, Fourier transform was performed on each signal to obtain its frequency domain representation X. i (f). Subsequently, the cross-spectral density function S between the two signals is calculated. i (f): S i (f)=E[X i [(f)×X(f)]; Where f is the frequency; E is the expectation operator; Xi X(f) and X(f) are respectively X i Fourier transforms of X(t) and X(t); X(f) is the Fourier transform of X(t) and X(t); i The complex conjugate of (f).

[0040] Cross-spectral density function S i (f) is a complex function with a phase angle θ i (f) directly reflects the phase difference between the two vibrations at frequency f. Based on this phase angle, the propagation delay τ of the vibration wave between the two points can be calculated. i (f): Where, τ i (f) represents the time delay of the vibration wave propagating between the two points; θ i (f) represents the phase angle; f represents the frequency.

[0041] If τ i If (f) > 0, it means that at frequency f, the vibration phase of measuring point i leads that of measuring point j, and energy is transferred from point i to point j. Conversely, if τ i If (f) < 0, then energy is transferred from point j to point i. By performing calculations across all measuring points within the area covered by the vibration sensor array 10, this module can construct a vector field characterizing the flow of vibration energy at a specific frequency. The output of this vector field can be visualized as a vibration energy transfer path map, where the direction of the vectors indicates the direction of energy flow, and the length or color of the vectors represents the intensity of the energy flow. The diagnostic analysis module 35 receives this map and, by analyzing the convergence points of the vector field, can identify the vibration energy convergence area.

[0042] The online impedance identification module 37 is used to identify and decouple the electromagnetic impedance and mechanical impedance of the motor under test in real time while the system performs closed-loop vibration control. To this end, the command output module 34, when generating the total drive current command, includes the fundamental current i... base (t) and the harmonic current i used to track the target vibration h In addition to (t), a preset broadband disturbance current i with a low energy amplitude is also injected. pert (t). The spectrum of this disturbance current covers the frequency range where impedance identification is required, and can be generated, for example, using a pseudo-random binary sequence signal. Therefore, the total current injected into the driver is: i total (t)=i base (t)+i h (t)+i pert (t); Among them, i total (t) represents the total drive current; i h(t) represents the harmonic current; i base (t) is the sinusoidal fundamental current used to maintain the motor at a specific speed and load; i pert (t) represents a preset broadband disturbance current with a low energy amplitude.

[0043] The online impedance identification module 37 synchronously acquires the minute change ΔU(t) in the terminal voltage of the motor under test caused by the disturbance current and the minute change ΔV(t) in the vibration velocity measured by the vibration sensor array 10. In the frequency domain, the electromagnetic-mechanical coupling characteristics of the motor under test can be described by the following set of equations: U(ω)=Z e (ω)×I(ω)+T me (ω)×V(ω); F(ω)=-T em (ω)×I(ω)+Z(ω)×V(ω); Where ω is the angular frequency; U(ω) and I(ω) are the phasors of the motor terminal voltage and injected current, respectively; V(ω) is the phasor of the vibration velocity at a specific position of the motor; F(ω) is the phasor of the external mechanical excitation force acting at that position, which can be considered as 0 in this system; Ze(ω) is the electromagnetic impedance of the motor; Z(ω) is the mechanical impedance of the motor; T me (ω) and T em (ω) is the electromechanical coupling transfer function.

[0044] Because i pert Given an excitation ΔU(t) and its corresponding responses ΔV(t), the resulting signals can be precisely measured. By performing Fourier transforms on these disturbance and response signals and substituting them into the aforementioned equations, Z can be solved within the frequency band covered by the disturbance current. e The values ​​of Z(ω) and Z(ω) are obtained. The diagnostic analysis module 35 periodically acquires and records Z. e The curves of Z(ω) and Z(ω). By comparing the changes in impedance curves at different times or under different operating conditions, the physical root cause can be attributed. For example, a change in the frequency or amplitude of a resonance peak on the Z(ω) curve indicates a change in the characteristics of the motor's mechanical structure (such as bearings or housing); while Z... e The change in the (ω) curve indicates a change in the performance of the electromagnetic components of the motor (such as windings and magnets).

[0045] See attached document Figure 2 , Figure 2 This is a flowchart of a dynamic vibration testing method for a multi-degree-of-freedom resonant excitation motor according to an embodiment of the present invention. The method details the execution process of performing a complete test using the system of the present invention.

[0046] The method begins with step S1. In step S1, initialization settings are performed before the test. The operator sets or loads a preset target vibration profile V through the user interface of the central real-time control and analysis host 30. target (t). The target vibration profile is a multidimensional vector time series, the dimensions of which correspond to the number of measurement points in the vibration sensor array 10. It defines the time function of the vibration displacement, velocity, or acceleration that is expected to be present at each measurement point of the motor under test during the test. Simultaneously, the test operating parameters, such as the target speed and load of the motor, are set. These parameters are used to determine the fundamental current i. base The amplitude and frequency of (t).

[0047] Subsequently, the method proceeds to step S2, initiating real-time closed-loop tracking control. This step is a continuous cyclic process. In each step of this cycle, the vibration sensor array 10 acquires the actual vibration signals at each measuring point of the motor under test in real time and transmits them to the vibration state observer 31. The vibration state observer 31 processes the signals and converts them into a digitized actual vibration state vector V. actual (t). Controller 32 receives V actual (t) and preset V target (t), the vibration error vector V at the current moment is calculated by vector subtraction. error (t)=V target (t)-V actual (t). Harmonic calculation module 33 receives this V error (t), and using the inverse model of the internal electromagnetic mechanical transfer function, the set of harmonic current parameters required to compensate for this error is calculated.

[0048] In a preferred embodiment, step S3, namely the synchronous identification of online impedance, is executed in parallel with step S2. In this step, the instruction output module 34 integrates the harmonic current i calculated by the harmonic calculation module 33. h (t) and the fundamental current i set under operating conditions base (t) is superimposed with a broadband perturbation current i, which has low energy but a wide spectrum and is generated by an internal signal source. pert (t). These three factors are combined to form the digital waveform of the total drive current. The online impedance identification module 37 synchronously acquires data from i pert (t) The weak response of the motor terminal voltage and structural vibration caused by the excitation, and the electromagnetic impedance Z of the motor under test is continuously calculated. e (ω) and mechanical impedance Z(ω).

[0049] In step S4, current injection and vibration drive are performed. The command output module 34 converts the synthesized total drive current digital waveform into a drive signal and sends it to the high-bandwidth harmonic injection driver 20. According to this command, the driver 20 precisely injects the physical total drive current i into the motor under test. total (t). The current interacts with the motor's magnetic field, generating an electromagnetic excitation force superimposed on the main torque. This excitation force drives a change in the structural vibration of the motor under test. This changed vibration state is immediately captured by the vibration sensor array 10 in step S2, thus forming a high-response closed-loop control that continuously drives the actual vibration signal to track the target vibration profile.

[0050] In step S5, the closed-loop control process stops when the test reaches a preset duration or a certain termination condition is met. The central real-time control and analysis host 30 archives and saves all data recorded during the test. This data includes, but is not limited to: the complete actual vibration state vector V. actual (t) Time series, target vibration profile V target (t), vibration error vector V error (t) Time series, injected harmonic current parameter set The time series, and the electromagnetic impedance Z calculated by the online impedance identification module 37. e The curves or time sequence of the mechanical impedance Z(ω) before and after the test.

[0051] Finally, in step S6, post-test data analysis and diagnostic report generation are performed. The diagnostic analysis module 35 is activated and calls other analysis modules to process the saved data. For example, it calls the vibration energy flow analysis module 36 to process the saved V... actual (t) Cross-spectral density analysis is performed on the time series to calculate and plot the transmission path spectrum of vibration energy in the motor structure and identify energy accumulation areas. Subsequently, the diagnostic analysis module 35 integrates all analysis results, including vibration tracking accuracy assessment, spectral characteristics of the required harmonic current, energy flow spectrum, and changing trends of electromagnetic / mechanical impedance, and performs correlation analysis according to preset logical rules to finally generate a diagnostic report containing multi-dimensional diagnostic information and physical root cause attribution conclusions.

[0052] See attached document Figure 1 After the test, the diagnostic analysis module 35 is responsible for integrating and analyzing the various data recorded during the test to generate a diagnostic report containing multi-dimensional information about the dynamic characteristics of the tested motor. The specific generation process of this module is as follows: First, the diagnostic analysis module 35 quantitatively evaluates the actual vibration response accuracy of the tested motor when tracking the target vibration profile. This module retrieves the complete actual vibration state vector V from the storage unit. actual (t) and target vibration profile V target (t) is the time series data. For each measurement point i in the vibration sensor array 10, the module quantifies the tracking accuracy by calculating its root mean square error (RMSE) over the entire test duration T: Among them, V target,i (t) and V actual,i (t) represents the target vibration and actual vibration time functions at measurement point i, respectively; T is the test duration. This indicates the calculation of the average value over the entire time period T; RMSE i This represents the root mean square error (RMSE) of the i-th measurement point. The calculated RMSE for each measurement point... i The value is written into the report as a result of the response accuracy assessment; ∫ represents the integral over time t.

[0053] Secondly, the diagnostic analysis module 35 performs a spectral distribution analysis on the harmonic current injected to maintain the target vibration profile. This module retrieves the set of harmonic current parameters recorded by the harmonic calculation module 33 throughout the test. Or directly retrieve the synthesized total harmonic current waveform I h (t). By performing a Fast Fourier Transform on the harmonic current data, this module can obtain its frequency domain distribution spectrum. If significant amplitude peaks appear at one or more specific frequency points in this spectrum, it indicates that the structure of the tested motor has mechanical resonance at these frequency points, and the system needs to continuously inject energy at the corresponding frequency to maintain the target vibration. These frequency points and their corresponding harmonic current amplitudes are recorded as key indicators of the dynamic characteristics of the motor structure.

[0054] Then, the diagnostic analysis module 35 integrates and presents the results calculated by the vibration energy flow analysis module 36. This module receives vector field data characterizing the vibration energy flow from the vibration energy flow analysis module 36 and overlays it onto a two-dimensional or three-dimensional structural schematic diagram of the motor under test, generating a visual map of the vibration energy accumulation region. In this map, the direction and length of the vector arrows clearly indicate the main transmission path and intensity distribution of vibration energy within the motor structure at a specific excitation frequency. The image processing algorithm within the module automatically identifies regions in the vector field where flux converges significantly and highlights them as vibration energy accumulation regions.

[0055] Next, the diagnostic analysis module 35, based on the output of the online impedance identification module 37, forms a conclusion of physical root cause analysis. This module retrieves the electromagnetic impedance Z recorded during the test. e The module calculates the frequency response curves of impedance Z(ω) and mechanical impedance Z(ω) and compares them with stored reference impedance curves (e.g., impedance data of the motor at the time of manufacture or under healthy conditions). Through differential calculation, the module identifies the frequency bands and shapes where the impedance curves change significantly. Based on a preset expert rule base, the module makes logical judgments: if the change mainly occurs on the Z(ω) curve, such as a shift in the frequency of a resonant peak or a change in the peak height, the attribution is a change in mechanical structure characteristics; if the change mainly occurs on the Z(ω) curve... e If the curve is on the (ω) curve, the attribution conclusion is that the performance of the electromagnetic components has changed.

[0056] Finally, the diagnostic analysis module 35 correlates and synthesizes all the above analysis results to generate a final diagnostic report. This report not only independently lists the vibration tracking accuracy, key harmonic frequencies, energy accumulation area map, and physical root cause attribution conclusions, but also cross-references them. For example, the report correlates the conclusions of the physical root cause attribution analysis (such as "decreased mechanical stiffness") with the specific physical locations in the visualization map of the vibration energy accumulation area (such as "the connection between the front cover and the bearing housing"), thus providing a complete diagnostic chain from "fault nature" to "fault location".

Claims

1. A multi-degree of freedom resonant excitation motor dynamic vibration testing system, characterized in that, The method comprises the following steps: a vibration sensor array is arranged at a predetermined position of a motor under test, and is used to collect real-time vibration signals of the motor under test; a high-bandwidth harmonic injection driver is electrically connected to the motor under test, and is used to inject a driving current containing a fundamental current and a harmonic current into the motor under test; a central real-time control and analysis host comprises: a vibration state observer, which is used to receive the real-time vibration signals collected by the vibration sensor array; a controller, which is used to compare the real-time vibration signals received by the vibration state observer with a preset target vibration profile, and to calculate and generate control instructions in real time through a closed-loop control algorithm; a harmonic calculation module, which is used to calculate the amplitude, frequency and phase of the harmonic current required by the high-bandwidth harmonic injection driver to inject into the motor under test according to the control instructions generated by the controller; an instruction output module, which is used to send the harmonic current determined by the harmonic calculation module to the high-bandwidth harmonic injection driver together with the fundamental current, so as to control the high-bandwidth harmonic injection driver to inject the driving current containing the fundamental current and the harmonic current into the motor under test, thereby driving the real-time vibration signals of the motor under test to track the target vibration profile, and thus ending the test; a diagnostic analysis module, which is used to generate a diagnostic report on the dynamic characteristics of the motor under test based on the real-time vibration signals collected by the vibration sensor array and the harmonic current calculated by the harmonic calculation module after the test is ended.

2. The multi-degree of freedom resonant excited motor dynamic vibration testing system of claim 1, wherein, The closed-loop control algorithm specifically comprises: calculating a vibration error according to the preset target vibration profile and the real-time vibration signals collected by the vibration sensor array; based on the vibration error and according to an electromagnetic mechanical transfer function model of the motor under test, reversely calculating the amplitude, frequency and phase of the harmonic current required to compensate for the vibration error, and generating corresponding control instructions.

3. The multi-degree of freedom resonant excited motor dynamic vibration testing system of claim 1, wherein, The central real-time control and analysis host further comprises a vibration energy flow analysis module; the vibration energy flow analysis module is used to calculate the transmission path and distribution of vibration energy in the structure of the motor under test in real time based on the cross-spectral density relationship between a plurality of the real-time vibration signals collected by the vibration sensor array.

4. The multi-degree of freedom resonant excited motor dynamic vibration testing system of claim 3, wherein, The central real-time control and analysis host is further used to: according to the calculation result of the vibration energy flow analysis module and by referring to a preset excitation focal point region, adaptively adjusting the phase of the harmonic current to actively regulate the transmission path of the vibration energy, so that the vibration energy is concentrated in the excitation focal point region.

5. The multi-degree of freedom resonant excited motor dynamic vibration testing system of claim 1, wherein, The central real-time control and analysis host further comprises an online impedance identification module; the online impedance identification module is used to identify and decouple the electromagnetic impedance and mechanical impedance of the motor under test in real time in the closed-loop control algorithm.

6. The multi-degree of freedom resonant excited motor dynamic vibration testing system of claim 5, wherein, The online impedance identification module identifies and decouples in the following way: controlling the high-bandwidth harmonic injection driver to superimpose a preset wideband disturbance current while injecting the driving current. The electromagnetic impedance and the mechanical impedance are calculated synchronously by analyzing the weak vibration response caused by the broadband disturbance current.

7. The multi-degree of freedom resonant excited motor dynamic vibration testing system of claim 5, wherein, The central real-time control and analysis host is further configured to: Based on the changes of the electromagnetic impedance and the mechanical impedance decoupled by the online impedance identification module over time or working conditions, a physical root cause analysis is performed on the changes of the dynamic characteristics of the measured motor to distinguish whether the changes are caused by the performance change of the electromagnetic components or the change of the mechanical structure characteristics.

8. The multi-degree of freedom resonant excited motor dynamic vibration testing system of claim 2, wherein, The electromagnetic-mechanical transfer function model is an inverse transfer function model, and the central real-time control and analysis host directly calculates the required harmonic current from the vibration error by using the inverse transfer function model.

9. The multi-degree of freedom resonant excited motor dynamic vibration testing system of claim 1, wherein, The diagnostic report includes at least one or a combination of the following: The actual vibration response accuracy evaluation of the measured motor when tracking the target vibration profile; the spectrum distribution analysis of the harmonic current required to maintain the target vibration profile; the visualization atlas of the vibration energy collection area; and the conclusion of the physical root cause analysis.

10. A method of dynamic vibration testing of a multi-degree-of-freedom resonant excited motor, characterized by, The application is applied to the multi-degree-of-freedom resonant excitation motor dynamic vibration test system of any one of claims 1-9, comprising the following steps: S1, setting a target vibration profile of a measured motor; S2, real-time collecting actual vibration signals of the measured motor by a vibration sensor array; S3, comparing the actual vibration signals with the target vibration profile to calculate a vibration error; S4, based on the vibration error, calculating a harmonic current required to compensate for the vibration error in real time by a closed-loop control algorithm; S5, controlling a high-bandwidth harmonic injection driver to combine the harmonic current and a fundamental current into a driving current and inject the driving current into the measured motor, so that the actual vibration signals of the measured motor track the target vibration profile in real time, and the test ends; S6, after the test ends, identifying a vibration energy collection area in the structure based on the cross-spectral density relationship between the actual vibration signals, and performing a physical root cause analysis based on the changes of the electromagnetic impedance and the mechanical impedance of the measured motor identified online to generate a diagnostic report.

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