Cooling fan motor function test system

Abstract

According to the cooling fan motor function test system provided by the embodiment of the invention, based on a time division multiplexing mechanism of three states of driving, measurement and silence which are unified and coordinated by a control module, a motor is normally driven by a power driving board in a driving state; in a measurement state, the power driving board turns off the upper bridge arm and turns on the lower bridge arm to eliminate switching noise, and the sensor array collects current and voltage signals; in a silent state, all the power switches are turned off to create an electromagnetic silent environment for collecting noise signals. The system isolates an interference source, can complete high-fidelity acquisition of multiple parameters in continuous dynamic operation of the motor, and provides a reliable data basis for accurate performance evaluation and fault diagnosis. Therefore, the upper computer can execute reliable analysis and diagnosis, and the accuracy and reliability of a test result are improved.

Description

Technical Field

[0001] This application relates to the field of motor testing technology, and in particular to a functional testing system for a cooling fan motor. Background Technology

[0002] The fan motor, a core component of cooling fans, is typically a brushless DC motor. Its performance and reliability directly affect the heat dissipation efficiency and overall operational stability of electronic devices. Therefore, conducting comprehensive and precise functional testing of the motor during production and quality control is a necessary process to ensure the quality of the final product.

[0003] Current testing methods typically require acquiring multiple physical parameters simultaneously during motor operation to assess its condition. This requires providing the motor with a drive circuit that matches its operating characteristics. Currently, drive circuits employing pulse width modulation (PWM) technology are widely used due to their high efficiency and precise control performance, adjusting the motor's output by controlling the high-speed switching of power devices.

[0004] However, the inherent voltage and current transients of high-speed switching of power devices generate strong electromagnetic interference. This leads to a conflict between drive and measurement requirements. The switching process necessary for driving the motor affects the signal environment required for high-precision measurements, significantly reducing the signal-to-noise ratio of the raw signal acquired from the sensor, making it difficult to accurately extract characteristic information reflecting the true state of the motor.

[0005] To mitigate the aforementioned interference problems, several conventional improvement measures exist in the prior art. For example, adding a filter network to the measurement circuit to attenuate noise at specific frequencies, or applying software filtering algorithms to the acquired data in the digital domain. Furthermore, interference coupling can be reduced by enhancing electromagnetic shielding and physical isolation, or by performing tests of different items sequentially in a time-sharing manner to avoid mutual interference. However, these measures all have limitations. Filtering methods may introduce signal distortion or fail to handle interference in the same frequency band; shielding and isolation measures increase system complexity and cost; and time-sharing testing disrupts the spatiotemporal correlation of data under continuous operation, failing to reflect the true comprehensive state of the motor's dynamic operation. These limitations collectively make it difficult to extract effective feature information from contaminated data, thus affecting the accuracy and reliability of fault diagnosis. Summary of the Invention

[0006] To overcome the aforementioned problems in the prior art, this disclosure provides a functional testing system for a cooling fan motor. Specifically, this application is implemented through the following technical solution: A functional testing system for a cooling fan motor includes a control module, a power drive board, a sensor array, and a host computer; the power drive board includes an upper bridge arm power switch connected to the motor under test and a lower bridge arm power switch connected to ground. The control module is used to generate a status indication signal and send it to the power drive board and the sensor array; the status indication signal is used to instruct the power drive board and the sensor array to switch to a specified working state, which is a drive state, a measurement state, or a silent state. The power drive board is used to respond to the status indication signal, drive the motor to run in the driving state, turn off the upper bridge arm power switch and turn on the lower bridge arm power switch in the measurement state, and turn off the upper bridge arm power switch and the lower bridge arm power switch in the silent state. The sensor array is used to acquire the current and voltage signals of the motor in the measurement state, acquire the noise signal of the motor in the silent state, continuously acquire the speed and temperature signals of the motor, and send the acquired signals to the control module; The control module is also used to perform analog-to-digital conversion on the signals collected by the sensor array, generate corresponding digital signals, and send them to the host computer. The host computer is used to output test analysis results based on the digital signal.

[0007] Further, the generation of the status indication signal includes: Periodically and continuously generate state indication signals that indicate the driving state, the measurement state, and the silent state.

[0008] Furthermore, the starting time for the control module to perform analog-to-digital conversion on the current and voltage signals collected by the sensor array is controlled by a first synchronization trigger signal; the starting time for the analog-to-digital conversion on the noise signal is controlled by a second synchronization trigger signal. The first synchronization trigger signal is triggered after a first preset time delay after the start of the measurement state, and the second synchronization trigger signal is triggered after a second preset time delay after the start of the silent state. The host computer is also used to calculate the total power of the motor based on the current signal and voltage signal after analog-to-digital conversion.

[0009] Furthermore, the host computer is specifically used to analyze the digital signal based on a preset fault diagnosis strategy; the fault diagnosis strategy includes correlation analysis of current harmonic features and noise spectrum features extracted within the same time period to diagnose a specified type of fault.

[0010] Furthermore, the fault diagnosis strategy also includes fusing and analyzing the speed signal features and temperature signal features extracted within the same time period with the current harmonic features and noise spectrum features to diagnose a specified type of fault.

[0011] Furthermore, the specified type of fault includes at least one of the following: motor bearing wear, rotor dynamic imbalance, winding turn short circuit, permanent magnet demagnetization, and air gap unevenness.

[0012] Furthermore, the host computer is also used to analyze the current signal after analog-to-digital conversion to obtain the total harmonic distortion rate of the current signal and the amplitude ratio of a specified harmonic. The deviations of the total harmonic distortion rate and the amplitude ratio of a specified harmonic from the corresponding preset thresholds are obtained, and the motor is determined to be in the optimal working state based on the deviations.

[0013] Furthermore, it also includes a load simulation module, which is connected between the power drive board and the motor under test, and is used to provide a simulated load for the motor under test during the test. The control module is also used to receive test instructions from the host computer and control the load simulation module to apply a simulated load related to the speed of the motor under test based on the test instructions; the simulated load is a dynamic load that changes according to a preset load curve, and the preset load curve simulates the aerodynamic load characteristics of the cooling fan in the actual air duct system.

[0014] Furthermore, the control module is also used to output a PWM signal or a VSP signal to the power drive board to control the speed of the motor in the driving state.

[0015] The rotational speed signal is the rotor position signal; the control module is also used to obtain the number of rotor pole pairs of the motor, and determine the rotational speed of the motor based on the number of rotor pole pairs and the rotational speed signal.

[0016] Furthermore, the system also includes a digital tube; the digital tube is connected to the control module; both the digital tube and the host computer are used to receive and display digital signals sent by the control module; the digital signals include signals of rotational speed, current, voltage, and power.

[0017] This specification's embodiments are based on a time-division multiplexing mechanism of three states—"drive-measurement-silent"—coordinated by the control module. In the drive state, the power drive board normally drives the motor; in the measurement state, the power drive board turns off the upper bridge arm and turns on the lower bridge arm to eliminate switching noise, while the sensor array collects current and voltage signals; in the silent state, all power switches are turned off to create an electromagnetically silent environment for noise signal acquisition. The system isolates interference sources and can complete high-fidelity acquisition of multiple parameters during continuous dynamic motor operation, providing a reliable data foundation for accurate performance evaluation and fault diagnosis. Accordingly, the host computer can perform reliable analysis and diagnosis, improving the accuracy and reliability of test results. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of a cooling fan motor function testing system provided in the embodiments of this specification; Figure 2 This is a schematic diagram illustrating an application example of the cooling fan motor function testing system provided in the embodiments of this specification. Detailed Implementation

[0019] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0020] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0021] It should be understood that although the terms first, second, third, etc., may be used in this application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0022] Fan motors, the core actuators of cooling fans, are typically brushless DC motors. Their performance and reliability directly affect the heat dissipation efficiency and overall operational stability of electronic devices. In environments with stringent requirements for continuous operation, such as data center servers, communication base stations, medical devices, and high-precision industrial control equipment, the functional integrity of the motor is a key factor in ensuring system safety. Therefore, comprehensive and precise functional testing during motor manufacturing and assembly is an indispensable step in the product quality control process.

[0023] Current testing methods require simultaneously acquiring multiple key parameters of the motor while it is running to assess its condition. These parameters typically include the operating current and voltage of the motor windings to calculate power consumption and efficiency and determine the quality of electrical connections; the noise generated by the motor during operation to analyze the assembly quality of its mechanical components and the condition of its bearings; the temperature of the motor housing to verify the heat dissipation design; and the real-time speed of the motor to confirm that its speed regulation performance meets specifications. The foundation for these tests is providing a controllable drive power supply to the motor. Modern drive circuits commonly employ pulse width modulation (PWM) technology, which regulates the output voltage by controlling the high-speed switching of power semiconductor devices, thereby precisely controlling the motor's speed and torque.

[0024] However, while the high-speed switching of power devices enables precise driving, it also induces drastic voltage and current transients in the circuit, generating strong broadband electromagnetic interference. This inherent physical phenomenon leads to a core testing dilemma: the switching noise necessary for driving the motor conflicts with the clean signal environment desired for high-precision measurements. Specifically, in electrical parameter measurements, voltage spikes and current glitches generated during the switching process are superimposed on the actual motor operating waveform, interfering with the accurate extraction of subtle features such as the effective current value, ripple content, and harmonic components. These subtle features are often sensitive indicators of potential defects such as early degradation of winding insulation or slight magnetic circuit imbalance.

[0025] In acoustic measurements, the power switching frequency and its high-frequency harmonic components radiate or conduct to acoustic sensors, forming stable background electrical noise. This noise can easily mask mechanical abnormalities caused by bearing fatigue, blade imbalance, or structural resonance, leading to decreased sensitivity or even failure of sound-based fault detection methods. Furthermore, if current sensors, voltage sensors, and noise sensors in the testing system use independent and non-synchronized sampling clocks for data acquisition, the acquired data will lack a unified time reference. This temporal inaccuracy prevents the system from reliably establishing instantaneous correlations between different physical quantities; for example, it cannot confirm whether a specific current fluctuation occurs at the same time as a specific acoustic event, thus severely limiting the possibility of comprehensive fault diagnosis based on multi-sensor data fusion.

[0026] To address the aforementioned interference issues, common countermeasures each have their limitations. Adding analog filters to the sensor signal chain can attenuate noise in specific frequency bands, but it introduces phase delay and may distort the useful signal, and it struggles to handle interference components overlapping with the signal spectrum. Software filtering of the acquired data in the digital domain is effective only if the signal-to-noise ratio of the original signal is sufficient, and it offers limited improvement over noise aliasing that occurs during analog-to-digital conversion, while also increasing the processor's computational burden. Strengthening electromagnetic shielding and isolation measures has some effect, but it increases system complexity and cost. While performing electrical and acoustic tests sequentially avoids mutual interference, it disrupts the inherent synchronization between multiple physical parameters of the motor under real continuous operation, resulting in test results that cannot fully reflect the comprehensive dynamic operating state of the motor.

[0027] Therefore, in the testing scenarios of cooling fans with strict requirements for reliability, energy efficiency and noise, it is necessary to achieve high-fidelity and high-synchronization acquisition of multiple physical parameters under the actual pulse width modulation drive condition of the motor, and fundamentally suppress the influence of interference generated by the drive circuit itself on the measurement channel.

[0028] Please see Figure 1 and Figure 2 This specification provides a cooling fan motor function testing system, including a control module, a power drive board, a sensor array, and a host computer. The control module is used to generate a status indication signal and send it to the power drive board and the sensor array; the status indication signal is used to instruct the power drive board and the sensor array to switch to a specified working state, which is a drive state, a measurement state, or a silent state.

[0029] One of the key aspects of this system lies in the status indication signals defined and output by the control module. These status indication signals are not single control commands, but rather a set of synchronous timing commands that simultaneously and consistently indicate to both the power drive board and the sensor array which preset operating state should be entered. The system is configured with three periodic operating states: drive state, measurement state, and silent state. Switching between these three states constitutes a complete test cycle, essentially physically isolating the three tasks—motor drive, electrical measurement, and acoustic measurement—that would interfere with each other in traditional solutions, using a precise time-division multiplexing strategy. The control module can be implemented using logic chips such as FPGAs.

[0030] The power drive board includes an upper bridge arm power switch connected to the motor under test and a lower bridge arm power switch connected to ground; the power drive board is used to respond to the status indication signal to drive the motor to run in the driving state, turn off the upper bridge arm power switch and turn on the lower bridge arm power switch in the measurement state, and turn off the upper bridge arm power switch and the lower bridge arm power switch in the silent state.

[0031] The power driver board, as the execution end of the system, consists of an upper bridge arm power switch connected to the power supply and a lower bridge arm power switch connected to the reference ground.

[0032] In drive mode, the power drive board operates its upper and lower bridge arm switches normally according to the pulse width modulation signal generated by the control module, so as to drive the motor under test to reach and maintain the set speed and torque, simulating its real working load.

[0033] When the status indicator signal switches to the measurement state, the power drive board changes its internal topology. Specifically, it turns off all upper bridge arm power switches and simultaneously turns on all lower bridge arm power switches. This operation, while cutting off the drive power input, provides a low-impedance freewheeling path to ground for the induced current that continuously exists in the motor windings due to the inductive characteristics. This avoids high-voltage spikes caused by sudden current changes and creates an electrical environment without upper bridge arm switch operation noise at this moment.

[0034] When entering the silent state, the power drive board further shuts off all lower bridge arm power switches, putting all power switching devices in the off state, thereby eliminating any switching action and conducted noise in the power stage circuit, providing an electromagnetic environment with extremely low background noise for acoustic measurements.

[0035] The sensor array is used to acquire the current and voltage signals of the motor in the measurement state, acquire the noise signal of the motor in the silent state, continuously acquire the speed and temperature signals of the motor, and send the acquired signals to the control module.

[0036] The sensor array, acting as the sensing unit, operates in sync with the state switching of the power drive board. During the measurement period, the current and voltage sensors in the array are activated, acquiring the analog current and voltage signals generated by the motor in this electrically silent environment. During the silent period, the noise sensor in the array is activated, acquiring the analog mechanical noise signal radiated by the motor body in an environment with virtually no electromagnetic noise interference. Simultaneously, the speed and temperature sensors operate independently of the aforementioned state switching, continuously acquiring the real-time speed pulse signal and temperature analog signal of the motor, respectively. All acquired raw analog signals are aggregated and sent to the control module.

[0037] The control module is also used to perform analog-to-digital conversion on the signals collected by the sensor array, generate corresponding digital signals, and send them to the host computer.

[0038] In the embodiments described in this specification, the control module combines timing scheduling and data preprocessing functions. The control module receives all analog signals from the sensor array and converts these analog signals into digital signals that can be processed by the digital system through its internal or associated analog-to-digital converter (ADC). This conversion process can be achieved through the ADC integrated into the control module, ensuring accurate mapping from continuous physical quantities to discrete digital information. After conversion, the control module sends the organized digital signal stream to the host computer.

[0039] The host computer is used to receive the digital signal and output test analysis results based on the digital signal.

[0040] The host computer receives multi-dimensional signal data uploaded by the control module, which has been synchronously acquired and digitized. Based on this multi-dimensional data reflecting the electrical, mechanical, thermal, and dynamic operating status of the motor, the host computer runs built-in signal processing and fault diagnosis algorithms. These algorithms can perform in-depth analysis of digital signals, such as calculating current harmonics, extracting noise spectrum features, evaluating speed stability and temperature rise curves, and further using feature fusion and pattern recognition technologies to comprehensively determine the motor's performance status and whether there are potential faults.

[0041] Finally, the host computer outputs a structured test analysis report or specific pass / fail judgment results, thereby completing the automated and intelligent testing of the cooling fan motor function.

[0042] Further, the generation of the status indication signal includes: Periodically and continuously generate state indication signals that indicate the driving state, the measurement state, and the silent state.

[0043] In this embodiment, the control module generates the status indication signal in a periodic cyclical process, and the content of the status indication signal alternates between the driving state, the measurement state, and the silent state in a fixed order.

[0044] This cycle can be based on the system's master clock frequency, or it can be synchronized with the frequency of the pulse width modulation carrier used by the power driver board, or have a defined multiple relationship with it. Within each such cycle, the status indicator signal will sequentially point to the three operating states mentioned above.

[0045] Therefore, the sequence of status indication signals presents an infinite loop pattern of drive, measurement, silence, re-drive, re-measure, and re-silence on the time axis, which constitutes the basic timing framework for the operation of the test system. This ensures that the drive operation of the motor and the acquisition operation of different physical quantities can be arranged and executed regularly and without overlap in time.

[0046] In one embodiment of the present invention, the start time for the control module to perform analog-to-digital conversion on the current and voltage signals collected by the sensor array is controlled by a first synchronization trigger signal; the start time for the noise signal to perform analog-to-digital conversion is controlled by a second synchronization trigger signal. The first synchronization trigger signal is triggered after a first preset time following the start of the measurement state, and the second synchronization trigger signal is triggered after a second preset time following the start of the silent state.

[0047] The host computer is also used to calculate the total power of the motor based on the current signal and voltage signal after analog-to-digital conversion.

[0048] The control module is responsible for performing analog-to-digital conversion on various signals collected by the sensor array. In this embodiment, a precise synchronous triggering mechanism is introduced during the conversion process to ensure that various signals can be accurately and stably collected in their corresponding working states.

[0049] Specifically, the start time of the analog-to-digital conversion of current and voltage signals by the control module is controlled by the first synchronous trigger signal. Similarly, the start time of the analog-to-digital conversion of noise signals is controlled by an independent second synchronous trigger signal. The timing of the generation of these two trigger signals is closely related to the switching of the system's operating state.

[0050] Once the measurement state is entered, the power drive board changes its switching configuration to create a quiet environment suitable for electrical measurements. However, circuit state switching may be accompanied by transient responses, such as parasitic capacitance discharge or inductor freewheeling, which can affect the accuracy and stability of the initial acquired signals. Therefore, the control module does not immediately initiate analog-to-digital conversion of the current and voltage signals at the start of the measurement state. Instead, it waits for a pre-set delay, i.e., the first preset time, until the electrical circuit stabilizes before triggering the first synchronization trigger signal. After this signal is issued, the control module initiates the analog-to-digital conversion process for the current and voltage signals, thereby ensuring that the converted digital signals accurately reflect the steady-state electrical characteristics of the motor windings and avoiding the acquisition of data containing transient noise.

[0051] Similarly, when switching to silent mode, all power switches on the power drive board are turned off to provide an environment with extremely low electromagnetic interference for acoustic measurements. However, the complete shutdown of the switching devices and the response of the associated filtering circuits may require a brief settling time. The control module also does not immediately acquire noise signals at the start of silent mode; instead, it delays for a second preset time before triggering the second synchronization trigger signal. This signal triggers the initiation of analog-to-digital conversion of the noise signal. This delay allows the electromagnetic environment of the system to fully settle, ensuring that the noise sensor primarily acquires the mechanical noise generated by the motor itself, rather than electromagnetic interference residual from circuit switching actions, thereby improving the signal-to-noise ratio and reliability of the acoustic measurement results.

[0052] As an embodiment of the present invention, the host computer is specifically used to analyze the digital signal based on a preset fault diagnosis strategy; the fault diagnosis strategy is to correlate and analyze the current harmonic features and noise spectrum features extracted within the same time period to diagnose a specified type of fault.

[0053] The host computer receives multi-dimensional digital signals uploaded by the control module, which have undergone synchronous acquisition and analog-to-digital conversion. These digital signals contain information such as current, voltage, noise, speed, and temperature generated by the motor during periodic test cycles.

[0054] The core of the fault diagnosis strategy lies in the fusion and correlation analysis of multi-sensor information. Specifically, the diagnostic program inside the host computer first extracts current and noise data within the same time period from the continuous digital signal stream. For the current data, the program extracts its harmonic component characteristics, such as the amplitude of a specific harmonic and the total harmonic distortion rate, using signal processing algorithms. For the synchronously acquired noise data, the program extracts its spectral characteristics, such as the energy distribution and peak frequency of a specific frequency band, through spectrum analysis.

[0055] The host computer performs correlation analysis on the current harmonic characteristics extracted within the same time period and the noise spectrum characteristics. This correlation analysis aims to discover coupling relationships or synergistic change patterns between two different physical quantity characteristics. For example, a specific type of early bearing wear fault may simultaneously cause an increase in a specific subharmonic component in the motor current, generating a corresponding high-frequency resonance peak in the noise spectrum. Through a pre-set fault diagnosis model or rule base, the host computer can identify these correlated feature patterns and map them to specific fault types, such as poor winding insulation, bearing defects, rotor imbalance, or air gap eccentricity.

[0056] Therefore, by executing this time-aligned multi-dimensional feature correlation analysis strategy, the host computer achieves the transformation from massive test data to accurate fault diagnosis. This not only improves the sensitivity of potential defect detection and early warning capabilities, but also enhances the credibility and interpretability of fault diagnosis results, ultimately outputting comprehensive test analysis results to complete the intelligent evaluation of motor functions.

[0057] Furthermore, the fault diagnosis strategy also includes fusing and analyzing the speed signal features and temperature signal features extracted within the same time period with the current harmonic features and noise spectrum features to comprehensively diagnose the specified type of fault.

[0058] Building upon the aforementioned electro-acoustic correlation analysis, the dynamic operating and thermal states of the motor are further integrated. The fault diagnosis strategy also requires a "fusion analysis" based on the speed and temperature signal characteristics extracted within the same time period, combined with the aforementioned current harmonic characteristics and noise spectrum characteristics. Speed ​​signal characteristics can include speed fluctuation rate and synchronicity, directly reflecting the dynamic performance of mechanical load and drive control; temperature signal characteristics reflect the motor's heat accumulation and heat dissipation. Integrating these characteristics with electro-acoustic features means that the diagnostic model needs to comprehensively consider the complex interactions between electrical anomalies, mechanical vibrations, dynamic response, and temperature rise. For example, a short circuit between winding turns may simultaneously cause current harmonic distortion, additional electromagnetic noise (noise spectrum changes), abnormal temperature rise due to efficiency degradation (temperature characteristic changes), and possible speed fluctuations. Through this multi-dimensional fusion analysis, the system can achieve a more comprehensive and robust integrated fault diagnosis, reducing the false alarm and false negative rates of single-feature diagnosis, and is particularly suitable for distinguishing fault types with similar symptoms.

[0059] Furthermore, the specified types of faults include at least one of the following: motor bearing wear, rotor dynamic imbalance, winding inter-turn short circuit, permanent magnet demagnetization, and air gap unevenness. Among these, bearing wear and rotor dynamic imbalance are primarily mechanical faults, which are reflected in the vibration and noise spectrum and can also modulate the current; winding inter-turn short circuit, permanent magnet demagnetization, and air gap unevenness are electromagnetic faults, which directly affect the motor's magnetic field and circuitry, and are prominently manifested in current harmonics, while also potentially causing specific vibration noise.

[0060] Specifically, both inter-turn short circuits in the windings and localized demagnetization of the permanent magnets are electromagnetic anomalies within the motor. Both can lead to significant changes in current harmonic components (e.g., an increase in the third harmonic) and generate specific electromagnetic noise, making them easily confused when simply analyzing electro-acoustic correlation characteristics. Combining speed and temperature characteristics, inter-turn short circuits cause changes in winding resistance, resulting in increased local copper losses and thus abnormal and rapid localized temperature rises at and near the fault point (abnormal temperature signal characteristics). Simultaneously, due to increased electromagnetic torque pulsation, slight fluctuations in speed or sluggish response may occur (changes in speed signal characteristics).

[0061] Local demagnetization of permanent magnets mainly manifests as a weakening of the air gap magnetic field, leading to a decrease in the motor's back electromotive force. To maintain the same speed, the drive current will increase overall, but the temperature rise distribution may be relatively uniform and the trend gradual (the temperature signal characteristic change pattern is different from that of a short circuit). More importantly, demagnetization directly leads to a decrease in the motor's output torque capability under the same load, manifested as a larger speed drop or slower recovery when a step load is applied (the dynamic speed response characteristics are abnormally obvious).

[0062] By integrating four dimensions of features—current, noise, speed dynamic response, and temperature change patterns—the host computer's diagnostic model can more reliably distinguish between these two serious faults that initially exhibit similar electrical and acoustic characteristics.

[0063] Furthermore, the host computer is also used to analyze the current signal after analog-to-digital conversion to obtain the total harmonic distortion rate of the current signal and the amplitude ratio of a specified harmonic. The deviations of the total harmonic distortion rate and the amplitude ratio of a specified harmonic from the corresponding preset thresholds are obtained, and the motor is determined to be in the optimal working state based on the deviations.

[0064] Based on the fine processing of the current signal after analog-to-digital conversion, the host computer can determine the motor's operating efficiency level under the current conditions. Specifically, the host computer's analysis function includes two stages: signal feature extraction and status determination.

[0065] In the first stage, the signal feature extraction stage, the host computer processes the digital current signal, which has already undergone analog-to-digital conversion, transmitted from the control module. The goal of this processing is to quantify the deviation of the current waveform from an ideal sine wave. To achieve this, the host computer performs frequency domain analysis, for example, by converting the time-domain current signal into a frequency-domain representation using a Fast Fourier Transform algorithm. Based on this spectral data, the host computer calculates two characteristic parameters. The first key parameter is the total harmonic distortion (THD) of the current signal. This parameter characterizes the ratio of the total effective value of all harmonic components except the fundamental component to the effective value of the fundamental component, serving as a comprehensive indicator of the overall purity and sinusoidal nature of the current waveform. The second key parameter is the amplitude proportion of a specific harmonic. Here, the specific harmonic usually refers to the low-order harmonics that have a significant impact in the motor drive system, such as the fifth or seventh harmonic. Its amplitude proportion reflects the proportion of the distortion component at a specific frequency in the overall signal.

[0066] In the subsequent second stage, the state determination stage, the host computer imports the calculated characteristic parameters into a preset evaluation logic. This logic relies on a set of pre-set reference thresholds stored in the host computer. These thresholds correspond to the total harmonic distortion (THD) and the amplitude proportion of each specified harmonic, respectively. Their values ​​are typically set based on motor design specifications, theoretical optimal models, or historical health data. The host computer performs the operation of obtaining the deviation between the calculated THD value and the corresponding preset threshold, and simultaneously obtaining the deviation between the amplitude proportion of each specified harmonic and its corresponding preset threshold. Then, a built-in judgment algorithm is used to make a comprehensive judgment based on these deviations. If the analysis results show that the deviations of the THD and the amplitude proportions of each specified harmonic are within acceptable tolerance ranges, the host computer can determine that the motor's operating state under the current load and speed combination is close to the theoretical optimal efficiency point. Conversely, if the deviation of any characteristic parameter exceeds the predetermined tolerance, it indicates that there is abnormal distortion in the current waveform. This distortion is usually accompanied by additional copper and iron losses, and the host computer can determine that the motor is not operating in an optimal efficiency state.

[0067] The host computer performs an analysis process that extracts the total harmonic distortion rate and the proportion of specified harmonic amplitudes from the current signal and compares these quantitative features with preset thresholds, thereby achieving a quantitative assessment of whether the motor is in its optimal efficiency operating state.

[0068] As an embodiment of the present invention, the system further includes a load simulation module, which is connected between the power drive board and the motor under test, and is used to provide a simulated load for the motor under test during the test.

[0069] This system serves the comprehensive and realistic requirements of motor functional testing. In practical applications, the load characteristics (manifested as drag torque) of a cooling fan motor's driven blades are not constant; they vary with factors such as speed, duct design, and air density. If the test system only drives the motor to idle, it cannot fully assess its electrical performance, mechanical characteristics, temperature rise, and control stability under real load conditions.

[0070] The load simulation module creates an environment closer to actual operating conditions for testing by simulating real load conditions. It can provide loads of different sizes and characteristics according to testing needs, such as constant torque loads, speed-proportional loads (simulating typical aerodynamic loads of fans), and even dynamically changing loads. When the power drive board drives the motor according to the control module's instructions, the motor must overcome the torque applied by the load simulation module to rotate. The current, voltage, temperature rise, and generated noise and vibration spectra of its windings will all exhibit corresponding characteristic changes depending on the load.

[0071] Therefore, the load simulation module enables the host computer to analyze data based on richer operating conditions. The system can test key indicators of the motor under different loads, such as starting characteristics, efficiency curves, overload capacity, and steady-state speed accuracy. More importantly, in terms of fault diagnosis, some potential defects (such as slight bearing wear or magnetic circuit asymmetry) may not be obvious under no-load conditions, but they will be triggered or amplified under specific loads, making them easier for the sensor array to capture and for the host computer's diagnostic strategies to identify. The existence of this module enhances the overall testing system's ability to evaluate the comprehensive performance and reliability of the motor.

[0072] Furthermore, the control module is also used to receive test instructions from the host computer and control the load simulation module to apply a simulated load associated with the speed of the motor under test based on the test instructions.

[0073] The host computer, acting as the core of test management, generates macroscopic "test instructions" based on the test plan (such as rated load test, overload test, and efficiency curve plotting) and sends them to the control module. The control module, as the real-time control unit, is responsible for parsing these instructions and generating corresponding precise control signals to drive the load simulation module.

[0074] In this embodiment, the load (resistance torque) output by the load simulation module is not a fixed value, but a function of the real-time speed of the motor under test. This correlation can usually be achieved through a preset control algorithm or lookup table. For example, the control module continuously collects the motor's speed signal and uses a "load-speed" function model (such as...) The target load value to be applied is calculated in real time by adjusting the load simulation device (such as the excitation current of the magnetic powder brake) to simulate the core load characteristics of the cooling fan—the aerodynamic load torque is approximately proportional to the square of the speed.

[0075] Therefore, this embodiment can automatically simulate the actual stress state of the motor at different operating speeds. This allows the test to be conducted not only at a few discrete, static load points, but also to provide a continuous load that matches the actual operating characteristics of the motor throughout its dynamic process of acceleration, deceleration, and steady-state operation. This provides a basis for accurately evaluating the motor's dynamic response performance, speed regulation stability, and parameters such as current and temperature rise under real variable operating conditions.

[0076] Furthermore, the simulated load provided by the load simulation module is a dynamic load that changes according to a preset load curve, which simulates the aerodynamic load characteristics of the cooling fan in the actual air duct system.

[0077] In this embodiment, the load curve can be a predefined load planning trajectory on the time axis or speed axis, which may include multiple stages and complex changes. For example, a complete test load curve may include: a gradually increasing load during the start-up phase, a load that increases with the square of the speed during the acceleration phase, a constant load at the rated speed, a periodically fluctuating load simulating wind resistance changes, and a step load during overload testing, etc.

[0078] As an embodiment of the present invention, the sensor array includes a current sensor and a voltage sensor, and the signal output terminals of the current sensor and the voltage sensor are connected to an analog switch; the analog switch is controlled by the state indication signal and only conducts the current signal and the voltage signal to the control module during the measurement state.

[0079] An analog switch is connected in series between the current sensor and the voltage sensor in the sensor array, which are responsible for collecting the core electrical parameters. An analog switch is a device whose on / off state can be controlled by a digital signal.

[0080] In drive mode, the power drive board is performing high-frequency switching to drive the motor, and the circuit is filled with strong switching noise and transient voltage / current fluctuations. If the signal paths of the current and voltage sensors are open at this time, these powerful interferences will flood into the subsequent acquisition circuit without hindrance, severely overwhelming the motor's actual operating signal. The analog switch remains off in this state, physically cutting off the path for interference noise to enter the control module.

[0081] During measurement, according to the system design, the power drive board has switched to a specific configuration (upper bridge arm off, lower bridge arm on), actively stopping all active switching actions that might cause interference, creating an electrical quiet window for electrical measurements. At this moment, the analog switch accurately receives the command of the status indication signal and turns on, transmitting the analog signals output by the current sensor and voltage sensor at this moment, which are almost unaffected by switching noise, to the control module for analog-to-digital conversion.

[0082] In the silent state, designed for acoustic measurements, extremely low electromagnetic background noise is required. The analog switch is turned off again to further ensure that no unnecessary signal paths introduce coupling noise.

[0083] This embodiment achieves dual gating of key electrical measurement signals in both the time domain and physical path through an analog switch controlled by a global status signal. This ensures that the current and voltage signals transmitted to the control module reflect the true operating state of the motor windings to the greatest extent possible, while effectively blocking the switching noise of the drive circuit. This lays an irreplaceable high-quality data foundation for subsequent accurate analysis and reliable fault diagnosis.

[0084] Furthermore, the control module is also used to output a PWM signal or a VSP signal to the power drive board to control the speed of the motor in the driving state. The speed signal is the rotor position signal; the control module is also used to obtain the number of rotor pole pairs of the motor, and determine the speed of the motor based on the number of rotor pole pairs and the speed signal.

[0085] In this embodiment, the control module is responsible for outputting pulse width modulation signals or voltage speed regulation signals to the power drive board during drive mode. These two signals serve as control commands for the motor, used to set and adjust the expected operating speed of the motor under test. The power drive board responds to these control signals by switching its internal power switches on and off, driving the motor to reach and maintain the corresponding speed level.

[0086] To achieve closed-loop control and accurate measurement of motor speed, the system needs to acquire the actual motor speed. This process relies on sensing the motor rotor's motion. The system continuously collects raw electrical signals reflecting the instantaneous changes in rotor position through a sensor array; this signal is the speed signal, which can be a square wave pulse sequence generated by a Hall sensor or orthogonal pulses output by an encoder. However, the frequency of these raw position signals cannot be directly equated to mechanical speed in revolutions per minute (RPM). The control module needs to perform the conversion using the motor's inherent structural parameter—the number of rotor pole pairs. The host computer or user interface is responsible for providing or setting this rotor pole pair number to the control module. After acquiring this parameter, the control module substitutes the received rotor position signal frequency into the basic relationship between speed, frequency, and pole pairs to calculate and accurately determine the motor's real-time mechanical speed.

[0087] Furthermore, the system also includes a digital tube; the digital tube is connected to the control module; both the digital tube and the host computer are used to receive and display digital signals sent by the control module; the digital signals include signals of rotational speed, current, voltage, and power.

[0088] At the information display level, the system employs a dual display architecture combining local and remote displays. The system includes a digital tube display unit electrically connected to the control module. The control module, as the core of data aggregation and processing, organizes and formats various digital signals continuously acquired and converted from analog to digital. These digital signals encompass key physical quantities characterizing the motor's operating status, including calculated rotational speed, instantaneous current and voltage values ​​under measured conditions, and their derived power values. The control module simultaneously sends these processed digital signal streams to two terminals: the locally connected digital tube and a host computer connected via a communication interface. The digital tube, acting as a local real-time monitoring unit, intuitively displays these key parameters in digital form, providing immediate feedback for on-site operations. Meanwhile, the host computer, through its graphical user interface, receives and displays the same dataset in richer formats, such as charts and digital instruments, and utilizes its enhanced data processing capabilities for in-depth analysis, recording, and test report generation.

[0089] The embodiments of the subject matter and functional operation described in this specification can be implemented in the following ways: digital electronic circuits, tangibly embodied computer software or firmware, computer hardware including the structures disclosed in this specification and their structural equivalents, or combinations thereof. Embodiments of the subject matter described in this specification can be implemented as one or more computer programs, i.e., one or more modules of computer program instructions encoded on a tangible, non-transitory program carrier for execution by a data processing apparatus or for controlling the operation of a data processing apparatus. Alternatively or additionally, the program instructions may be encoded on artificially generated propagation signals, such as machine-generated electrical, optical, or electromagnetic signals, which are generated to encode information and transmit it to a suitable receiving device for execution by the data processing apparatus. The computer storage medium may be a machine-readable storage device, a machine-readable storage substrate, a random or serial access memory device, or combinations thereof.

[0090] The processing and logic described in this specification can be executed by one or more programmable computers that execute one or more computer programs to perform corresponding functions by operating on input data and generating output.

[0091] Suitable computers for executing computer programs include, for example, general-purpose and / or special-purpose microprocessors, or any other type of central processing unit. Typically, the central processing unit receives instructions and data from read-only memory and / or random access memory. The basic components of a computer include a central processing unit for implementing or executing instructions and one or more memory devices for storing instructions and data. Typically, a computer will also include one or more mass storage devices for storing data, such as disks, magneto-optical disks, or optical disks, or the computer will be operatively coupled to such mass storage devices to receive data from or transfer data to them, or both. However, a computer is not required to have such devices. Furthermore, a computer can be embedded in another device, such as a mobile phone, a personal digital assistant (PDA), a mobile audio or video player, a game console, a global positioning system (GPS) receiver, or a portable storage device such as a universal serial bus (USB) flash drive, to name a few.

[0092] Computer-readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media, and memory devices, such as semiconductor memory devices (e.g., EPROM, EEPROM, and flash memory devices), magnetic disks (e.g., internal hard disks or removable disks), magneto-optical disks, and CD-ROM and DVD-ROM disks. Processors and memory may be supplemented by or incorporated into dedicated logic circuitry.

[0093] While this specification contains numerous specific implementation details, these should not be construed as limiting the scope of any invention or the scope of the claims, but rather are primarily intended to describe features of specific embodiments of a particular invention. Certain features described in the various embodiments herein may also be implemented in combination in a single embodiment. Conversely, various features described in a single embodiment may also be implemented separately in various embodiments or in any suitable sub-combination. Furthermore, while features may function in certain combinations as described above and even initially claimed in this way, one or more features from a claimed combination may be removed from that combination in some cases, and a claimed combination may refer to a sub-combination or a variation thereof.

[0094] Similarly, although the operations are depicted in a specific order in the accompanying drawings, this should not be construed as requiring these operations to be performed in the specific order shown or sequentially, or requiring all illustrated operations to be performed to achieve the desired result. In some cases, multitasking and parallel processing may be advantageous. Furthermore, the separation of various system modules and components in the above embodiments should not be construed as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products.

[0095] Thus, specific embodiments of the subject matter have been described. Other embodiments are within the scope of the appended claims. In some cases, the actions recited in the claims may be performed in a different order and still achieve the desired result. Furthermore, the processes depicted in the drawings are not necessarily shown in a specific order or sequence to achieve the desired result. In some implementations, multitasking and parallel processing may be advantageous.

[0096] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A heat dissipation fan motor function test system, characterized in that, The system comprises a control module, a power drive board, a sensor array, and an upper computer; the power drive board comprises an upper bridge arm power switch connected with a motor to be measured and a lower bridge arm power switch connected with the ground; The control module is configured to generate a state indication signal and send the state indication signal to the power drive board and the sensor array; The state indication signal is configured to instruct the power drive board and the sensor array to switch to a specified working state, and the specified working state is a driving state, a measuring state, or a silent state; The power drive board is configured to drive the motor to operate in the driving state, turn off the upper bridge arm power switch and turn on the lower bridge arm power switch in the measuring state, and turn off the upper bridge arm power switch and the lower bridge arm power switch in the silent state in response to the state indication signal; The sensor array is configured to collect a current signal and a voltage signal of the motor in the measuring state, collect a noise signal of the motor in the silent state, continuously collect a rotating speed signal and a temperature signal of the motor, and send the collected signals to the control module; The control module is further configured to perform analog-to-digital conversion on the signals collected by the sensor array, generate corresponding digital signals, and send the digital signals to the upper computer; The upper computer is configured to output a test analysis result based on the digital signals.

2. The heat-dissipating fan motor function test system according to claim 1, wherein, The generation of the state indication signal comprises: Periodically and continuously generating state indication signals indicating the driving state, the measuring state, and the silent state.

3. The heat dissipation fan motor function test system according to claim 1, wherein The starting time of analog-to-digital conversion of the current signal and the voltage signal collected by the sensor array by the control module is controlled by a first synchronization trigger signal, and the starting time of analog-to-digital conversion of the noise signal is controlled by a second synchronization trigger signal; The first synchronization trigger signal is triggered after the measuring state starts with a delay of a first preset time, and the second synchronization trigger signal is triggered after the silent state starts with a delay of a second preset time; The upper computer is further configured to calculate the total power of the motor based on the current signal and the voltage signal after analog-to-digital conversion.

4. The heat-dissipating fan motor function test system according to claim 1, wherein, The upper computer is specifically configured to analyze the digital signals based on a preset fault diagnosis strategy; the fault diagnosis strategy comprises correlating the current harmonic features and the noise spectrum features extracted in the same time period to diagnose a specified type of fault.

5. The heat-dissipating fan motor function test system according to claim 4, wherein, The fault diagnosis strategy further comprises fusing the rotating speed signal features and the temperature signal features extracted in the same time period with the current harmonic features and the noise spectrum features for analysis to diagnose a specified type of fault.

6. The heat-dissipating fan motor function test system according to claim 5, wherein, The specified type of fault comprises at least one of motor bearing wear, rotor dynamic imbalance, winding inter-turn short circuit, permanent magnet demagnetization, and air gap unevenness.

7. The heat-dissipating fan motor function test system according to claim 1, wherein, The upper computer is further configured to analyze the current signal after analog-to-digital conversion to obtain the total harmonic distortion rate of the current signal and the amplitude ratio of a specified harmonic. The total harmonic distortion and the amplitude proportion of the specified harmonic are obtained, and deviations of the total harmonic distortion and the amplitude proportion of the specified harmonic from corresponding preset thresholds are obtained.

8. The heat-dissipating fan motor function test system according to claim 1, wherein, The load simulation module is connected between the power drive board and the motor under test, and is configured to provide a simulated load for the motor under test during testing. The control module is further configured to receive a test instruction from the host computer, and control the load simulation module to apply a simulated load associated with the motor under test speed based on the test instruction.

9. The heat-dissipating fan motor function test system according to claim 1, wherein, The control module is further configured to output a PWM signal or a VSP signal to the power drive board to control the motor speed in the drive state. The speed signal is a rotor position signal, and the control module is further configured to obtain a rotor pole pair number of the motor, and determine the motor speed based on the rotor pole pair number and the speed signal.

10. The heat-dissipating fan motor function test system according to claim 1, wherein, The control module is further configured to output a digital signal to the digital tube and the host computer. The digital signal includes signals of speed, current, voltage, and power.

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