Replaceable high-resistivity permanent magnet motor test system and method

Abstract

The invention discloses a replaceable high-resistivity permanent magnet motor test system and method, and belongs to the technical field of motor tests. The method is used for solving the problem that performance advantages of a high-resistivity permanent magnet in the aspects of inhibiting eddy-current loss and reducing temperature rise are difficult to accurately evaluate in the prior art. The test method comprises the following steps: step 1, selecting and installing a permanent magnet rotor assembly; 2, hardware debugging is completed; 3, test parameters are set, and a cooling module is started; 4, starting the permanent magnet motor to be tested, and applying a load by a loading device; step 5, collecting performance data of the permanent magnet motor to be tested; and step 6, after a group of tests is completed, disassembling the current replaceable permanent magnet rotor assembly, replacing the current replaceable permanent magnet rotor assembly with a conventional resistivity permanent magnet rotor assembly, repeating the steps 1-5, and obtaining multiple groups of test data of the conventional resistivity permanent magnet rotor assembly. The method can effectively verify and accurately evaluate the significant advantages of the high-resistivity permanent magnet in inhibiting eddy current loss and temperature rise in the motor.

Description

Technical Field

[0001] This invention belongs to the field of permanent magnet motor testing technology, and particularly relates to a test system and method for a replaceable high resistivity permanent magnet motor. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs), with their high power density, excellent efficiency, and superior dynamic response characteristics, have become core power devices in fields such as new energy vehicles, industrial servo systems, and wind power generation. According to statistics from the International Energy Agency (IEA), the global market size for PMSMs has exceeded $30 billion, with high-performance neodymium iron boron (NdFeB) permanent magnets accounting for over 75%. However, as motors develop towards higher speeds and higher power densities, the eddy current losses caused by the inherent low resistivity (typically ≤150 μΩ·cm) of traditional permanent magnets are becoming increasingly prominent. Studies show that at high speeds above 10,000 rpm, eddy current losses within the permanent magnet can account for 30% to 40% of the total losses. This not only leads to decreased efficiency but also causes local temperature rises exceeding 150°C, resulting in irreversible demagnetization of the magnet and severely restricting the reliability of the motor system.

[0003] To reduce eddy current losses, high-resistivity permanent magnets (such as composite bonded magnets and nanocrystalline magnets) have become a research hotspot in recent years. The HILIC series magnets developed by TDK Corporation of Japan have a resistivity as high as 500 μΩ·cm, and under the same operating conditions, their eddy current losses are only 1 / 5 of those of traditional magnets. However, the industrial application of high-resistivity magnets still faces two major technical bottlenecks: First, the increase in magnet resistivity is often accompanied by remanence (B0.05). r ) and coercivity (H cj The decrease in electromagnetic properties requires optimization of material formulation and structural design to balance electromagnetic performance; secondly, existing motor testing systems lack dedicated testing schemes for high resistivity magnets, making it difficult to quantify their efficiency advantages and temperature rise characteristics under actual working conditions.

[0004] Currently, traditional permanent magnet motor test systems mainly suffer from the following defects: (1) Poor replaceability of permanent magnets: Most systems adopt an integral rotor structure, and the permanent magnets are fixed by epoxy resin potting. When replacing them, high-temperature demagnetization or destructive disassembly is required. A single replacement takes more than 4 hours and is easy to damage the magnets. (2) Insufficient accuracy of dynamic loading: Load simulation mostly uses magnetic powder brakes for direct loading, but the problem of nonlinearity between excitation current and torque is not solved. At low torque (<10% of rated value), the error exceeds ±5%, which makes it impossible to accurately measure the low loss characteristics of high resistivity magnets. (3) Single method of temperature rise monitoring: Existing solutions rely on embedded thermocouples, but thermocouple wiring will destroy the rotor dynamic balance and cannot cover the entire temperature field of permanent magnets. Some scholars have tried to use infrared temperature measurement, but the emissivity correction error of rotating parts causes the temperature deviation to exceed ±3℃. (4) Lack of multi-parameter collaborative analysis: Electrical parameters (efficiency, power factor) and thermal parameters (temperature rise) are usually collected by independent equipment, and the data time scale is not synchronized (delay ≥100ms).

[0005] To address the aforementioned issues, several improvement solutions have been proposed. For example, one solution proposes a split rotor structure and bolted magnetic yoke; however, this solution fails to effectively solve the problem of centrifugal stress concentration under high-speed rotation, limiting its maximum speed to 8000 rpm. Another solution introduces a closed-loop cooling system to suppress temperature rise, but the complex piping design increases system inertia, making it difficult to meet the requirements of high dynamic load testing.

[0006] Therefore, there is an urgent need to develop a testing system specifically for high resistivity permanent magnets. This system should enable rapid replacement and accurate testing of magnets through modular design, and combine multi-source data fusion technology to reveal the performance evolution patterns, providing solid technical support for the engineering application of next-generation low-loss permanent magnet motors. Summary of the Invention

[0007] Based on the above analysis, the present invention aims to provide a test system and method for replaceable high resistivity permanent magnet motors, in order to solve the technical problem that the existing technology is unable to accurately evaluate the performance advantages of high resistivity permanent magnets in suppressing eddy current losses and reducing temperature rise, thereby restricting the research and development and application of high resistivity permanent magnet motors.

[0008] The objective of this invention is mainly achieved through the following technical solutions:

[0009] On one hand, the present invention provides a test method for a replaceable high resistivity permanent magnet motor, comprising the following steps:

[0010] Step 1: Select a suitable permanent magnet rotor assembly according to the model and specifications of the permanent magnet motor to be tested, and install the permanent magnet rotor assembly onto the motor mounting base of the test bench.

[0011] Step 2: Connect the loading device to the output shaft of the permanent magnet motor under test via a coupling, check the coaxiality and tightness of the connection, and at the same time connect the data acquisition module to the voltage, current, speed and temperature detection interfaces of the permanent magnet motor under test to complete the hardware debugging.

[0012] Step 3: Set the test parameters and start the cooling module to allow the cooling medium to circulate through the cooling channel of the permanent magnet motor under test according to the set flow rate and temperature.

[0013] Step 4: The permanent magnet motor to be tested starts running at the set speed. The loading device gradually applies the load according to the test requirements and monitors the motor's operating status in real time.

[0014] Step 5: Collect performance data of the permanent magnet motor under test according to the preset sampling frequency;

[0015] Step 6: After completing a set of tests, turn off the high resistivity permanent magnet motor and loading device. After the motor temperature drops to room temperature, disassemble the replaceable permanent magnet rotor assembly and replace it with a conventional resistivity permanent magnet rotor assembly. Repeat steps 1-5 to obtain multiple sets of test data for the conventional resistivity permanent magnet rotor assembly. Analyze the temperature rise difference between the high resistivity permanent magnet motor and the conventional resistivity permanent magnet motor through multiple sets of test data.

[0016] Furthermore, in step 3, when the cooling module is started, the cooling medium is circulated through the cooling channel of the high resistivity permanent magnet motor to be tested according to the set flow rate and temperature.

[0017] Furthermore, in step 3, the performance data includes the efficiency value η.

[0018] Furthermore, in step 3, the efficiency value η is used for efficiency difference analysis of permanent magnets; wherein, the efficiency value of a high resistivity permanent magnet is η. high The efficiency value η of a conventional resistivity permanent magnet low .

[0019] Furthermore, in step 3, the performance data also includes the stator winding temperature and the permanent magnet temperature; the temperature rise of the permanent magnet = stator winding temperature + permanent magnet temperature.

[0020] Furthermore, in step 5, the multiple sets of temperature rise data for the high resistivity permanent magnet include: temperature rise data 30 minutes after the high resistivity permanent magnet motor under test has been running stably, temperature rise data 60 minutes after the high resistivity permanent magnet motor under test has been running stably, and temperature rise data 90 minutes after the high resistivity permanent magnet motor under test has been running stably.

[0021] Furthermore, in step 6, multiple sets of test data for the conventional resistivity permanent magnet rotor assembly are obtained, including: temperature rise data 30 minutes after the conventional resistivity permanent magnet motor has been running stably, temperature rise data 60 minutes after the conventional resistivity permanent magnet motor to be tested has been running stably, and temperature rise data 90 minutes after the conventional resistivity permanent magnet motor to be tested has been running stably.

[0022] A difference analysis was performed on the temperature rise data of high resistivity permanent magnet motors and conventional resistivity permanent magnet motors.

[0023] Furthermore, in step 6, the efficiency difference analysis process includes:

[0024] 61. Before the experiment, measure the magnetic resistivity ρ of the high resistivity permanent magnet. high Similarly, before the experiment, the resistivity ρ of a conventional resistivity permanent magnet was measured. low ;

[0025] 62. After the experiment, the efficiency value η of the high resistivity permanent magnet under the same load was obtained through step 3. high The efficiency value η of conventional resistivity permanent magnets low ;

[0026] 63. Establish a quantitative model for efficiency improvement, defining the efficiency improvement rate Δη as:

[0027] And it satisfies the ratio of Δη to the resistivity of the magnet (ρ) high / ρ low The relationship is power-law, and the fitting formula for the efficiency improvement rate is: The coefficient k ranges from 0.15 to 0.25, and the exponent n ranges from 0.5 to 0.7.

[0028] The test method for the replaceable high resistivity permanent magnet motor also includes:

[0029] Step 64: Fit the experimental data using the least squares method to verify that the model correlation coefficient R2 of the efficiency improvement quantification model is ≥0.95, and optimize the resistivity design threshold of the high resistivity magnet accordingly.

[0030] This invention provides a test system for a replaceable high resistivity permanent magnet motor, used to implement the above-mentioned test method for a replaceable high resistivity permanent magnet motor; the test system includes a fixing device, a replaceable permanent magnet rotor assembly, a loading device, a data acquisition module, a control module, and a cooling module;

[0031] The fixing device is used to fix the replaceable permanent magnet rotor assembly and the loading device; the input end of the data acquisition module is connected to the detection interface of the high resistivity permanent magnet motor under test, and the output end is connected to the control module; the output end of the cooling module is connected to the cooling channel of the high resistivity permanent magnet motor under test, and the input end is connected to the cooling channel outlet of the high resistivity permanent magnet motor under test through a return pipe; the control module is electrically connected to the high resistivity permanent magnet motor under test, the loading device, the data acquisition module and the cooling module respectively.

[0032] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0033] (1) By comparing the temperature rise data of high resistivity permanent magnet motor with that of conventional resistivity permanent magnet motor, this invention verifies that high resistivity permanent magnet has a significant performance advantage in suppressing eddy current loss and reducing temperature rise.

[0034] (2) By designing a replaceable permanent magnet rotor assembly, the present invention can quickly replace permanent magnet units of different high resistivity specifications according to test requirements, without replacing the entire motor rotor or building multiple test platforms, greatly reducing the investment in test equipment, shortening the test cycle, and is suitable for testing various specifications of high resistivity permanent magnet motors, thereby improving the utilization rate of test equipment.

[0035] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0036] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0037] Figure 1 This diagram illustrates the temperature rise of the high resistivity permanent magnet motor and the conventional resistivity permanent magnet motor 30 minutes after they have stabilized during operation. Detailed Implementation

[0038] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0039] On one hand, the present invention provides a test method for a replaceable high resistivity permanent magnet motor, the test method comprising the following steps:

[0040] Step 1: Select a suitable replaceable permanent magnet rotor assembly according to the model and specifications of the high resistivity permanent magnet motor to be tested, install the replaceable permanent magnet rotor assembly on the motor mounting base of the test bench, and ensure that the replaceable permanent magnet rotor assembly is precisely connected to the rotor structure of the high resistivity permanent magnet motor to be tested.

[0041] Step 2: Connect the loading device to the output shaft of the high resistivity permanent magnet motor to be tested via a coupling, check the coaxiality and tightness of the connection, and at the same time connect the data acquisition module to the voltage, current, speed and temperature detection interface of the high resistivity permanent magnet motor to be tested to complete the hardware debugging.

[0042] Step 3: Set the test parameters through the control module. The test parameters include motor operating speed, loading torque, test duration and temperature control threshold; start the cooling module to make the cooling medium circulate through the cooling channel of the high resistivity permanent magnet motor to be tested according to the set flow rate and temperature.

[0043] Step 4: The control module sends a drive signal to start the high resistivity permanent magnet motor under test at the set speed. The loading device gradually applies the load according to the test requirements and monitors the motor's operating status in real time.

[0044] Step 5: The data acquisition module collects the performance data of the high resistivity permanent magnet motor under test according to the preset sampling frequency, and transmits the collected performance data to the storage unit of the control module; thus, multiple sets of temperature rise data corresponding to the current replaceable permanent magnet rotor assembly are obtained.

[0045] In step 5 above, the performance data includes the efficiency value η, stator winding temperature, and permanent magnet temperature. The temperature rise is equal to the stator winding temperature plus the permanent magnet temperature; the temperature rise data of the permanent magnet after the test is obtained through the stator winding temperature and the permanent magnet temperature. The efficiency value is used to calculate the efficiency difference analysis of the permanent magnet, where the efficiency value of the high resistivity permanent magnet is η. high The efficiency value η of a conventional resistivity permanent magnet low .

[0046] In step 5 above, multiple sets of temperature rise data include: temperature rise data (stator winding temperature + permanent magnet temperature) 30 minutes after the high resistivity permanent magnet motor under test has been running stably, temperature rise data (stator winding temperature + permanent magnet temperature) 60 minutes after the high resistivity permanent magnet motor under test has been running stably, and temperature rise data (stator winding temperature + permanent magnet temperature) 90 minutes after the high resistivity permanent magnet motor under test has been running stably.

[0047] Step 6: After completing a set of tests, turn off the high resistivity permanent magnet motor and loading device. After the temperature of the high resistivity permanent magnet motor drops to room temperature, disassemble the current replaceable permanent magnet rotor assembly and replace it with a permanent magnet rotor assembly of conventional resistivity specifications. Repeat steps 1-5 to obtain multiple sets of temperature rise data corresponding to the current conventional resistivity permanent magnet rotor assembly.

[0048] It should be noted that after the conventional resistivity permanent magnet rotor assembly is tested, the conventional resistivity permanent magnet motor and loading device under test are turned off. After the motor temperature drops to room temperature, the current replaceable permanent magnet rotor assembly is disassembled and replaced with permanent magnet rotor assemblies of different high resistivity specifications. Steps 1-5 are repeated to obtain multiple sets of test data for the replaceable permanent magnet rotor assemblies.

[0049] In step 6 above, multiple sets of temperature rise data corresponding to the permanent magnet rotor assembly with conventional resistivity specifications are obtained: temperature rise data (stator winding temperature + permanent magnet temperature) 30 minutes after the conventional resistivity permanent magnet motor to be tested has been running stably, temperature rise data (stator winding temperature + permanent magnet temperature) 60 minutes after the conventional resistivity permanent magnet motor to be tested has been running stably, and temperature rise data (stator winding temperature + permanent magnet temperature) 90 minutes after the conventional resistivity permanent magnet motor to be tested has been running stably.

[0050] The temperature rise data of the tested high resistivity permanent magnet motor was compared with that of the conventional resistivity permanent magnet motor, and the efficiency difference was analyzed.

[0051] The analysis of the temperature rise data between the high-resistivity permanent magnet motor and the conventional resistivity permanent magnet motor shows that after 30 minutes of operation, the high-resistivity permanent magnet motor has a temperature rise 3.5℃ lower than that of the conventional resistivity permanent magnet motor (e.g., ...). Figure 1 As shown in the figure; after 60 minutes of operation, the temperature rise of the high resistivity permanent magnet motor was 5.5℃ lower than that of the conventional resistivity permanent magnet motor; after 90 minutes of operation, the temperature rise of the high resistivity permanent magnet motor was 9.5℃ lower than that of the conventional resistivity permanent magnet motor; thus, it can be seen that the temperature rise of the high resistivity permanent magnet motor is significantly lower than that of the conventional resistivity permanent magnet motor, verifying that the high resistivity permanent magnet has a great performance advantage in suppressing eddy current losses and reducing temperature rise.

[0052] The above efficiency difference analysis process includes:

[0053] First, the resistivity ρ of the high resistivity permanent magnet was measured before the experiment. high Similarly, before the experiment, the resistivity ρ of a conventional resistivity permanent magnet was measured. low .

[0054] Secondly, after the experiment, the efficiency value η of the high resistivity permanent magnet under the same load was obtained through step 3. high The efficiency value η of conventional resistivity permanent magnets low ;

[0055] Finally, a quantitative model for efficiency improvement (i.e., the motor efficiency-resistivity model) is established, and the efficiency improvement rate Δη is defined as: And it satisfies the ratio of Δη to the resistivity of the magnet (ρ) high / ρ low The relationship is power-law, and the fitting formula for the efficiency improvement rate is: The coefficient k ranges from 0.15 to 0.25, and the exponent n ranges from 0.5 to 0.7.

[0056] Furthermore, the experimental data were fitted using the least squares method to verify that the model correlation coefficient R2 of the efficiency improvement quantification model was ≥0.95, and the resistivity design threshold of the high resistivity magnet was optimized accordingly.

[0057] When efficiency is improved, the correlation coefficient R of the quantitative model is... 2 When the value is below 0.95, it indicates that the current efficiency improvement quantification model cannot effectively support design optimization. In this case, starting from the efficiency improvement quantification model, we can explore the underlying reasons through data diagnosis, model improvement (e.g., introducing more variables), and method upgrades.

[0058] When the model correlation coefficient R² of the efficiency improvement quantification model is ≥ 0.95, the optimization process of the resistivity design threshold for high-resistivity magnets includes: First, using mathematical methods (such as differentiation) to determine the theoretical maximum efficiency point. Then, considering the hard constraints of mechanical strength, cost, and process feasibility, necessary corrections are made to this ideal value. Finally, sensitivity analysis is performed based on the flatness of the efficiency curve near the optimal value to construct a resistivity design threshold range that balances high performance and engineering feasibility, rather than a single absolute value, thereby achieving the optimization objective.

[0059] On one hand, the present invention provides a test system for a replaceable high-resistivity permanent magnet motor, including a test bench, a replaceable permanent magnet rotor assembly, a loading device, a data acquisition module, a control module, and a cooling module. The test bench is equipped with a motor mounting base and a loading device mounting base. The replaceable permanent magnet rotor assembly is detachably mounted on the motor mounting base. The loading device is fixed on the loading device mounting base and connected to the high-resistivity permanent magnet motor to be tested via a coupling. The input end of the data acquisition module is connected to the detection interface of the high-resistivity permanent magnet motor to be tested, and its output end is connected to the control module. The output end of the cooling module is connected to the cooling channel of the high-resistivity permanent magnet motor to be tested, and its input end is connected to the cooling channel outlet of the high-resistivity permanent magnet motor to be tested via a return pipe. The control module is electrically connected to the high-resistivity permanent magnet motor to be tested, the loading device, the data acquisition module, and the cooling module.

[0060] Compared with existing technologies, the replaceable high resistivity permanent magnet motor test system of the present invention solves the problems of difficult permanent magnet replacement, incomplete data acquisition and inaccurate temperature control, and realizes accurate testing and evaluation of the performance of high resistivity permanent magnet motors.

[0061] To position and fix the replaceable permanent magnet rotor assembly, the replaceable permanent magnet rotor assembly of the present invention includes a permanent magnet mounting shell, a high resistivity permanent magnet unit, and a positioning pin. The inner wall of the permanent magnet mounting shell is provided with a mounting groove adapted to the high resistivity permanent magnet motor rotor to be tested. The high resistivity permanent magnet unit is embedded in the mounting groove. Positioning holes are provided at both ends of the permanent magnet mounting shell. The positioning pin passes through the positioning holes and connects to the motor mounting base to realize the positioning and fixing of the replaceable permanent magnet rotor assembly.

[0062] Compared with the prior art, the replaceable permanent magnet rotor assembly of the present invention is connected to the motor mounting base through the positioning pin, which can realize the rapid replacement and precise positioning of the permanent magnet, and significantly shorten the test cycle.

[0063] In the replaceable permanent magnet rotor assembly, the high resistivity permanent magnet unit is made of neodymium iron boron permanent magnet material doped with high-resistivity metal powder (such as tungsten, molybdenum or niobium powder). For example, the high resistivity permanent magnet unit is made of neodymium iron boron permanent magnet material doped with high-resistivity metal powder tungsten; the high resistivity permanent magnet unit is made of neodymium iron boron permanent magnet material doped with high-resistivity metal powder molybdenum; the high resistivity permanent magnet unit is made of neodymium iron boron permanent magnet material doped with high-resistivity metal powder niobium.

[0064] The resistivity range of the aforementioned high resistivity permanent magnet unit is 200-1000 μΩ·cm.

[0065] Compared with existing technologies, the high-resistivity permanent magnet unit of this invention significantly improves the resistivity of the permanent magnet by doping it with high-resistivity metal powder, effectively suppressing eddy current losses. By setting the resistivity of the high-resistivity permanent magnet unit within the range of 200-1000 μΩ·cm, a balance between sufficiently high resistivity and the magnetic properties of the permanent magnet is achieved, thus realizing a balance in electromagnetic performance. This invention provides specific technical parameters for the preparation of high-resistivity permanent magnets, which is beneficial for mass production and quality control.

[0066] The loading device of the present invention adopts a magnetic powder brake or an eddy current dynamometer. The torque adjustment range of the loading device is 0-500 N·m, and the speed measurement accuracy is ±0.1 r / min.

[0067] Compared with existing technologies, firstly, this invention uses a magnetic powder brake or eddy current dynamometer to achieve continuously adjustable loads, suitable for simulating various operating conditions. Secondly, this invention limits the torque adjustment range of the loading device to 0-500 N·m, which has a wide coverage range and can meet the testing needs of small and medium power motors. Finally, this invention uses high-precision speed measurement (0.1 r / min) to ensure testing accuracy at various speeds, especially data reliability under low-speed, high-torque conditions.

[0068] It should be noted that this invention can accurately obtain the efficiency curves of the high resistivity permanent magnet motor under different loads and evaluate the performance advantages of high resistivity permanent magnets.

[0069] To achieve multiple data acquisitions, the data acquisition module of this invention includes a voltage sensor, a current sensor, a speed sensor, a temperature sensor, and a noise and vibration sensor. The voltage sensor and the current sensor are connected in parallel across the stator windings of the high resistivity permanent magnet motor under test. The speed sensor is installed on the output shaft of the high resistivity permanent magnet motor under test. The temperature sensor includes a platinum resistance sensor attached to the surface of the stator windings and a thermocouple sensor embedded inside the permanent magnet. The noise and vibration sensor is installed on the test bench near the high resistivity permanent magnet motor under test.

[0070] For example, a Pt100 platinum resistance sensor is attached to the surface of the stator winding, with a measurement range of -50℃ to 200℃ and an accuracy of ±0.1℃. Simultaneously, a type K thermocouple is embedded inside the permanent magnet, with a measurement range of 0℃ to 800℃ and an accuracy of ±1℃. By using these two sensors in combination, real-time temperature changes in both the stator winding and the permanent magnet can be monitored simultaneously, allowing for the evaluation of the effectiveness of the high-resistivity permanent magnet in suppressing eddy current losses and reducing temperature rise.

[0071] Compared with the prior art, the data acquisition module of the present invention can acquire data from thermocouple sensors embedded inside permanent magnets, enabling real-time monitoring of permanent magnet temperature and comprehensive evaluation of the performance of high resistivity permanent magnets under different operating conditions.

[0072] The control module of this invention includes a PLC controller, a touch screen, and a data storage unit; wherein, the touch screen communicates bidirectionally with the PLC controller for parameter setting and test data display; the data storage unit is connected to the PLC controller for storing test data, and the data storage unit supports USB data export function.

[0073] Compared with the prior art, the control module of the present invention coordinates the work of each module through a PLC controller, the touch screen facilitates parameter setting and data display, and the data storage unit supports USB data export for convenient subsequent analysis.

[0074] The cooling module of the present invention includes a cooling water tank, a water pump, a radiator, and a temperature controller; the input end of the water pump is connected to the cooling water tank, and the output end is connected to the cooling channel of the high resistivity permanent magnet motor to be tested through a pipe; the radiator is connected in series on the cooling medium return pipe, and the temperature controller is connected to the temperature sensor in the cooling water tank, controlling the start and stop of the radiator according to the detected temperature, so that the temperature of the cooling medium is maintained at 5-25℃.

[0075] First, the closed-loop cooling module design of this invention ensures the cyclical use of the cooling medium, improving cooling efficiency. Second, the linkage control between the temperature controller and the heat sink enables precise adjustment of the cooling medium temperature. Finally, the temperature control range of 5-25℃ adopted by this invention can adapt to different environments and testing requirements, simulating low-temperature conditions while ensuring stability during room-temperature testing.

[0076] For example, when testing a high-resistivity permanent magnet motor, the cooling water tank capacity is 100L and the water pump flow rate is 50L / min. The temperature controller uses a PID control algorithm to automatically start the radiator when the cooling water temperature exceeds 25°C and shut it off when the temperature is below 5°C. This allows the motor temperature to be stabilized within the set range during long-term high-load testing, accurately evaluating the heat dissipation performance of the high-resistivity permanent magnet.

[0077] Compared with the prior art, the cooling module of the present invention monitors the temperature of the cooling medium in real time through a temperature controller, automatically adjusts the start and stop of the radiator and the flow rate of the cooling medium, and ensures that the high resistivity permanent magnet motor under test maintains a suitable temperature environment during the test.

[0078] The test bench of this invention is welded from steel profiles. The bottom of the bench is equipped with a shock-absorbing pad made of nitrile rubber. The thickness of the shock-absorbing pad is controlled to be 10-20mm to reduce the impact of motor vibration on the test bench during the test.

[0079] Compared with existing technologies, firstly, the shock-absorbing pad of this invention can effectively reduce the impact of vibrations generated during motor operation on the test bench, improving the accuracy of test data. Secondly, the nitrile rubber material has good elasticity and oil resistance, making it suitable for long-term use. Furthermore, the 10-20mm thickness range can be selected according to the vibration characteristics of motors with different power ratings to achieve the best shock absorption effect.

[0080] For example, for a high-resistivity permanent magnet motor with a rated power of 100kW, four nitrile rubber vibration damping pads measuring 200mm × 200mm and 15mm thick can be installed at the bottom of the test bench. When the motor is running at full load, these damping pads can absorb 85-90% of the vibration energy, reducing the vibration transmitted to the ground to below 0.1g, ensuring the accuracy of the data collected by the vibration sensor, and helping to assess the impact of the high-resistivity permanent magnet on motor noise and vibration.

[0081] Compared with the prior art, the replaceable high resistivity permanent magnet motor test system and method of the present invention has the following advantages:

[0082] (1) High flexibility and reduced test costs: This invention designs a replaceable permanent magnet rotor assembly, which can quickly replace permanent magnet units of different high resistivity specifications according to test requirements. There is no need to replace the entire motor rotor or build multiple test platforms, which greatly reduces the investment in test equipment, shortens the test cycle, and is suitable for testing various specifications of high resistivity permanent magnet motors, thereby improving the utilization rate of test equipment.

[0083] (2) By embedding a thermocouple sensor inside the permanent magnet, the present invention can monitor the temperature change of the permanent magnet in real time. Combined with the temperature data of the stator winding, it can comprehensively evaluate the performance stability and reliability of the high resistivity permanent magnet under different working conditions.

[0084] (3) Adaptive cooling to ensure safe and stable test: The cooling module monitors the temperature of the cooling medium in real time through the temperature controller. Combined with the operating status of the high resistivity permanent magnet motor under test, it automatically adjusts the start and stop of the radiator and the flow rate of the cooling medium to ensure that the motor maintains a suitable temperature environment during the test, effectively avoids damage to the permanent magnet rotor assembly due to local overheating, and at the same time ensures that the test data is collected under stable temperature conditions, further improving the accuracy of the data and ensuring the safety and reliability of the test process.

[0085] (4) Easy to operate and highly practical: The control module is equipped with a touch screen, which facilitates the setting of test parameters and the real-time display of test data. The data storage unit supports USB data export, which facilitates data processing and analysis after the test. The test bench is equipped with shock-absorbing pads at the bottom, which can reduce the impact of motor vibration on the test bench and reduce the interference of vibration noise on test data. The overall system structure is compact, the operation process is simple, and it is easy to promote and apply, providing a reliable technical means for the research and development, performance testing and quality inspection of high resistivity permanent magnet motors.

[0086] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A test method for a replaceable high resistivity permanent magnet motor, characterized in that, Includes the following steps: Step 1: Select a suitable permanent magnet rotor assembly according to the model and specifications of the permanent magnet motor to be tested, and install the permanent magnet rotor assembly onto the motor mounting base of the test bench. Step 2: Connect the loading device to the output shaft of the permanent magnet motor under test via a coupling, check the coaxiality and tightness of the connection, and at the same time connect the data acquisition module to the voltage, current, speed and temperature detection interfaces of the permanent magnet motor under test to complete the hardware debugging. Step 3: Set the test parameters and start the cooling module to allow the cooling medium to circulate through the cooling channel of the permanent magnet motor under test according to the set flow rate and temperature. Step 4: The permanent magnet motor to be tested starts running at the set speed. The loading device gradually applies the load according to the test requirements and monitors the motor's operating status in real time. Step 5: Collect performance data of the permanent magnet motor under test according to the preset sampling frequency; Step 6: After completing a set of tests, turn off the high resistivity permanent magnet motor and loading device. After the motor temperature drops to room temperature, disassemble the replaceable permanent magnet rotor assembly and replace it with a conventional resistivity permanent magnet rotor assembly. Repeat steps 1-5 to obtain multiple sets of test data for the conventional resistivity permanent magnet rotor assembly. Analyze the temperature rise difference between the high resistivity permanent magnet motor and the conventional resistivity permanent magnet motor through multiple sets of test data.

2. The test method for a replaceable high resistivity permanent magnet motor according to claim 1, characterized in that, In step 3, when the cooling module is started, the cooling medium is circulated through the cooling channel of the high resistivity permanent magnet motor to be tested according to the set flow rate and temperature.

3. The test method for a replaceable high resistivity permanent magnet motor according to claim 2, characterized in that, In step 3, the performance data includes the efficiency value η.

4. The test method for a replaceable high resistivity permanent magnet motor according to claim 3, characterized in that, In step 3, the efficiency value η is used for efficiency difference analysis of permanent magnets; wherein, the efficiency value of a high resistivity permanent magnet is η. high The efficiency value of a conventional resistivity permanent magnet is η. low .

5. The test method for a replaceable high resistivity permanent magnet motor according to claim 3, characterized in that, In step 3, the performance data also includes the stator winding temperature and the permanent magnet temperature; the temperature rise of the permanent magnet = stator winding temperature + permanent magnet temperature.

6. The test method for a replaceable high resistivity permanent magnet motor according to claim 5, characterized in that, In step 5, the multiple sets of temperature rise data for the high resistivity permanent magnet include: temperature rise data 30 minutes after the high resistivity permanent magnet motor under test has been running stably, temperature rise data 60 minutes after the high resistivity permanent magnet motor under test has been running stably, and temperature rise data 90 minutes after the high resistivity permanent magnet motor under test has been running stably.

7. The test method for a replaceable high resistivity permanent magnet motor according to claim 6, characterized in that, In step 6, multiple sets of test data for the conventional resistivity permanent magnet rotor assembly are obtained, including: temperature rise data 30 minutes after the conventional resistivity permanent magnet motor has been running stably, temperature rise data 60 minutes after the conventional resistivity permanent magnet motor to be tested has been running stably, and temperature rise data 90 minutes after the conventional resistivity permanent magnet motor to be tested has been running stably. A difference analysis was performed on the temperature rise data of the high resistivity permanent magnet motor and the temperature rise data of the conventional resistivity permanent magnet motor.

8. The test method for a replaceable high resistivity permanent magnet motor according to claim 4, characterized in that, In step 6, the efficiency difference analysis process includes:

61. Before the experiment, measure the magnetic resistivity ρ of the high resistivity permanent magnet. high Similarly, before the experiment, the resistivity ρ of a conventional resistivity permanent magnet was measured. low ; 62. After the experiment, the efficiency value η of the high resistivity permanent magnet under the same load was obtained through step 3. high The efficiency value η of conventional resistivity permanent magnets low ; 63. Establish a quantitative model for efficiency improvement, defining the efficiency improvement rate Δη as: And it satisfies the ratio of Δη to the resistivity of the magnet (ρ) high / ρ low The relationship is power-law, and the fitting formula for the efficiency improvement rate is: The coefficient k ranges from 0.15 to 0.25, and the exponent n ranges from 0.5 to 0.

7.

9. The test method for a replaceable high resistivity permanent magnet motor according to claim 8, characterized in that, It also includes step 64, fitting the experimental data using the least squares method to verify that the model correlation coefficient R2 of the efficiency improvement quantification model is ≥0.95, and optimizing the resistivity design threshold of the high resistivity magnet accordingly.

10. A test system for a replaceable high-resistivity permanent magnet motor, characterized in that, The test system is used to implement the test method for a replaceable high resistivity permanent magnet motor according to any one of claims 1 to 9; the test system includes a fixing device, a replaceable permanent magnet rotor assembly, a loading device, a data acquisition module, a control module, and a cooling module; The fixing device is used to fix the replaceable permanent magnet rotor assembly and the loading device; the input end of the data acquisition module is connected to the detection interface of the high resistivity permanent magnet motor under test, and the output end is connected to the control module; the output end of the cooling module is connected to the cooling channel of the high resistivity permanent magnet motor under test, and the input end is connected to the cooling channel outlet of the high resistivity permanent magnet motor under test through a return pipe; the control module is electrically connected to the high resistivity permanent magnet motor under test, the loading device, the data acquisition module and the cooling module respectively.

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