Electromechanical hybrid energy feedback motor test system

Abstract

The invention discloses an electromechanical hybrid energy feedback motor test system, which comprises a shafting device, an electrical device and a measurement system, and is characterized in that the shafting device comprises an elastic coupling, a gearbox, an asynchronous generator and a hydraulic dynamometer, and the electrical device comprises an inlet wire transformer, a rectification power supply, an asynchronous generator and a four-quadrant frequency converter; the measurement system comprises voltage / current sensors arranged on the tested frequency converter and the four-quadrant frequency converter, and a field acquisition module connected with the voltage / current sensors, the tested frequency converter and the motor, and the four-quadrant frequency converter and the asynchronous generator. One part of mechanical energy output by the motor is consumed into heat energy by the hydraulic dynamometer, and the other part of the mechanical energy is converted into electric energy by the generator and fed back to the direct current bus through the four-quadrant frequency converter, so that a load mode of combining energy consumption and feedback is realized.

Description

Technical Field

[0001] This invention belongs to the field of power testing technology, and in particular relates to the performance testing and evaluation of power equipment such as generators and motors, specifically a motor test system with electromechanical hybrid energy feedback. Background Technology

[0002] In motor testing, the loads mainly include mechanical loads, electrical loads, and combined loads.

[0003] Mechanical loads include magnetic particle dynamometers, electric dynamometers, hydraulic dynamometers, and mechanical and electromagnetic brakes. Magnetic particle dynamometers adjust braking torque by changing the magnetic state of the magnetic particles, offering fast response and smooth torque control. They are particularly suitable for low-power motor testing, especially in applications requiring high torque control precision. Electric dynamometers convert the motor's mechanical energy into electrical energy to feed back to the grid, resulting in significant energy savings. In testing new energy vehicle motors, electric dynamometers can simulate various driving conditions, testing the motor's performance in both generator and motor modes. Hydraulic dynamometers utilize water resistance to generate load torque. They are simple in structure and stable in operation, although their adjustment performance is relatively poor. They are suitable for testing large motors with a limited speed range and low precision requirements. Mechanical brakes, such as disc brakes and block brakes, generate braking torque through mechanical friction. These loads are simple and reliable, but the braking process may involve wear and heat generation. They are commonly used for motors requiring less precision and intermittent testing. Electromagnetic brakes adjust braking torque by controlling the contact between brake pads and brake discs using electromagnetic force. They offer higher control precision than mechanical brakes and are used in motor tests that require frequent starts and stops and precise control of load torque.

[0004] Electrical loads include resistive loads, inductive loads, capacitive loads, and regenerative electronic loads. Resistive loads consume the electrical energy output by the motor by connecting resistors of varying resistance values, creating a load effect. Their advantages are simplicity and low cost, but they cannot regenerate energy, resulting in energy waste. They can be used in low-power motor tests where energy consumption requirements are not high and only simple load simulation is needed. Inductive and capacitive loads are mainly used to simulate the motor's operation under different power grid environments and power factors, studying the motor's reactive power characteristics and stability, such as in tests investigating the motor's harmonic effects on the power grid. Regenerative electronic loads can feed the electrical energy generated by the motor back to the power grid or other energy storage devices, improving energy utilization efficiency. They are widely used in high-power motor tests and in applications with high energy-saving requirements.

[0005] In motor testing, combined loads refer to combining different types of loads together to simulate more complex actual working conditions.

[0006] Combination of constant torque and constant power loads: In some industrial applications, motors may need to overcome constant torque loads during the startup phase, such as the friction of a conveyor belt. Once the motor reaches a certain speed, it may enter a constant power operation phase, such as during machine tool processing. In motor testing, a combination of a dynamometer and a power electronic load is used. During the startup phase, the dynamometer simulates a constant torque load, and after the motor is running normally, the power electronic load simulates a constant power condition.

[0007] Combining mechanical and electrical loads: For example, combining a hydraulic dynamometer with a resistive load. The hydraulic dynamometer is used to simulate the mechanical resistance of a motor in actual operation, such as the resistance of rotating equipment like fans and water pumps; the resistive load is used to consume the electrical energy output by the motor, thereby simulating the situation where the motor outputs power to both mechanical and electrical loads, such as in some factories where the motor drives a conveyor belt and supplies power to some small electrical equipment.

[0008] Combination of linear and nonlinear loads: Taking the combination of a brake (linear load) and an inductive-capacitive load (nonlinear load) as an example. The brake can provide a stable linear braking torque, while the inductive-capacitive load is used to simulate the reactive power changes and nonlinear load characteristics encountered by the motor in the power grid. This can be used to test the stability of the motor in complex power grid environments, such as the operation of the motor in a factory containing a large number of power electronic devices.

[0009] Combined loads offer the following application advantages.

[0010] Accuracy of simulating real-world operating conditions: Motors often encounter various complex load conditions in practical applications. Combined loads can more realistically simulate these actual operating conditions, thereby more accurately testing the motor's performance under various complex conditions, such as efficiency, torque characteristics, and heat generation.

[0011] Diversity of testing functions: A single load can usually only test the performance of a motor under a specific load type, while a combined load can test the comprehensive performance of a motor under the combined action of multiple loads, expanding the functional scope of motor testing. For example, it can test the dynamic performance of a motor during different load switching processes.

[0012] Chinese invention patent CN117369549A, "Control Method, Device, Equipment and Storage Medium of Hydropower Series Dynamometer System", describes a series connection of a hydraulic dynamometer and an electric dynamometer, as well as a torque distribution method, which solves the technical problems of poor control effect and high control difficulty in the existing control strategies of hydropower series dynamometer systems.

[0013] Chinese invention patent CN109696592A, "A Test Load Control Method, Device and Storage Medium for a Charger", describes the switching between two types of loads on a charger: energy-consuming load and energy-feeding load, which is achieved by sending instructions from a host computer.

[0014] Chinese invention patent CN115832689A, "A Control Method for a Test System of a Permanent Magnet Synchronous Motor," discloses a test system based on a multiphase permanent magnet synchronous motor, a grid-side rectifier, and a generator-side inverter. In this system, one or more sets of three-phase stator windings of the multiphase permanent magnet synchronous motor operate in torque control mode, while the remaining three-phase stator windings operate in speed control mode. In other words, part of the multiphase motor is a motor, and the other part is a generator load.

[0015] Chinese invention patent CN120629928A, "A Variable Frequency Motor Load Testing Device and Method," discloses a dual-motor structure design that uses two identical variable frequency speed-regulating asynchronous motors coaxially connected. The electrical energy generated by the test motor is fed back to the intermediate DC link via an inverter, achieving energy recycling. The advantages are: no need for complex load equipment, reduced fixed asset investment; use identical motors as test loads; and for different motor models, only the corresponding test motor needs to be replaced, improving versatility. Through voltage and current monitoring of the intermediate DC link and acquisition of motor speed and torque parameters, combined with a multi-dimensional performance evaluation model, accurate assessment of motor load performance is achieved, improving testing efficiency and meeting stringent testing requirements. However, it requires two identical motors. Summary of the Invention

[0016] The purpose of this invention is to provide a motor testing system with electromechanical hybrid energy feedback for high-power motor testing. This testing system can meet the requirements of motor testing at different voltage levels within a certain voltage range, motor load testing, and also has interlock protection function. The load has a certain energy-saving effect and good stability in the DC link.

[0017] The technical solution adopted by this invention to solve its technical problem is: a motor test system with electromechanical hybrid energy feedback, including a flexible coupling for connecting to the output end of the motor under test, the flexible coupling connecting an asynchronous generator and a hydraulic dynamometer respectively through a gearbox, wherein the asynchronous generator and the hydraulic dynamometer are respectively connected to the gearbox through coupling joint one and coupling joint two, the flexible coupling, gearbox, asynchronous generator, and hydraulic dynamometer constituting the main shaft system equipment of the motor test load; it also includes a DC bus for parallel connection with the frequency converter under test, rectifier power supply and four-quadrant frequency converter, and an input transformer connected to the rectifier power supply, the four-quadrant frequency converter being connected to the asynchronous generator, the input transformer, rectifier power supply, asynchronous generator, The four-quadrant frequency converter constitutes the main electrical equipment of the test load; it also includes voltage / current sensors installed on the frequency converter under test and the four-quadrant frequency converter, as well as field acquisition modules connected to the voltage / current sensors, the frequency converter under test and the motor, and the four-quadrant frequency converter and the asynchronous generator, respectively. The multiple field acquisition modules are connected to a measurement device consisting of a power analyzer, a centralized storage and display system; during high-power tests, the hydraulic dynamometer and the four-quadrant load consisting of the four-quadrant frequency converter and the asynchronous generator are simultaneously engaged, and the loads of the two are kept balanced; during medium and low-power tests, the hydraulic dynamometer is used as the load first; during speed and power mode switching tests, the hydraulic dynamometer is used first and set to constant torque mode.

[0018] To enhance support, the shaft system equipment includes a support bearing between the flexible coupling and the gearbox.

[0019] To accurately measure the load torque, a torque measuring shaft is connected between the support bearing and the gearbox, and a torque measuring instrument is connected to the torque measuring shaft.

[0020] Furthermore, the DC input side of the inverter under test and the DC output side of the four-quadrant inverter are respectively equipped with switch cabinets for DC side short circuit and overcurrent protection.

[0021] During the sudden load increase and decrease test, in order to ensure the stable and reliable DC bus voltage, an energy-dissipating resistor is connected in parallel on the DC bus to stabilize the DC bus voltage during the sudden load increase and decrease test.

[0022] Furthermore, the gearbox is a one-in-two-out gearbox, with a reduction ratio of 1:1.2 between the input shaft and the first output shaft, and a reduction ratio of 1:2.5 between the input shaft and the second output shaft.

[0023] The beneficial effects of this invention are as follows: 1. This provides a stable and reliable load test system for high-power motor testing. It is suitable for high-power motor testing, has multi-condition adaptability, DC side voltage stability and interlock protection functions, and has good energy-saving effect and operational reliability.

[0024] 2. This load test system meets the requirements for motor testing under various conditions, including high power, low power, and multiple control mode switching.

[0025] 3. The parallel resistor on the DC side of the load test system can effectively suppress DC voltage fluctuations.

[0026] 4. The load test system is equipped with interlock protection, which can interlock faults on the motor side and the load side, effectively ensuring test safety.

[0027] 5. This load test system provides a possibility that when two loads alone cannot meet the test requirements of the motor, the test requirements of the motor can be met by adding loads in parallel. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the motor test load system of the present invention; Figure 2 This is a schematic diagram of the shaft system equipment of the present invention; Figure 3 This is a schematic diagram of the structure of the electrical equipment of the present invention; Figure 4 This is a schematic diagram of the structure of the test management system of the present invention.

[0029] The labels on the attached figures are as follows: 11—Motor, 12—Flexible coupling, 13—Support bearing, 14—Torque measuring shaft, 15—Gearbox, 16—Coupling 1, 17—Coupling 2, 18—Asynchronous generator, 19—Hydraulic dynamometer, 20—Inverter under test, 21—Incoming transformer, 22—Rectifier power supply, 23—Four-quadrant inverter, 31—Torque measuring instrument, 32—Voltage / current sensor, 33—Field acquisition module, 34—Measuring device, 4—Energy consumption resistor. Detailed Implementation

[0030] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0031] Reference Figure 1 As shown, the present invention discloses a motor testing system with electromechanical hybrid energy feedback, which mainly includes shaft system equipment, electrical equipment and measurement system.

[0032] Reference Figure 2As shown, the shaft system includes a flexible coupling 12 for connecting to the output end of the test motor 11. The flexible coupling 12 is connected to the flange of the test motor 11. The flexible coupling 12 is connected to the asynchronous generator 18 and the hydraulic dynamometer 19 respectively through a one-in-two-out gearbox 15. The asynchronous generator 18 and the hydraulic dynamometer 19 are connected to the gearbox 15 respectively through coupling 16 and coupling 2 17. The mechanical energy output by the motor 11 is distributed to the asynchronous generator 18 and the hydraulic dynamometer 19 through the gearbox 15, forming an energy consumption load and a feedback load respectively. The flexible coupling 12, the gearbox 15, the asynchronous generator 18, and the hydraulic dynamometer 19 constitute the main shaft system of the motor test load of the present invention.

[0033] During high-power testing, the hydraulic dynamometer 19, the four-quadrant frequency converter 23, and the asynchronous generator 18 are simultaneously connected to form a four-quadrant load, and the loads of the two are kept balanced.

[0034] During low-to-medium power tests, hydraulic dynamometer 19 should be used as the load. During speed and power mode switching tests, hydraulic dynamometer 19 should be used and set to constant torque mode.

[0035] The flange of the permanent magnet motor 11 is connected to the flexible coupling 12 via hinge bolts. The flexible coupling 12 is connected to the shaft of the support bearing 13. The other end of the shaft of the support bearing 13 is connected to the torque measuring shaft. The torque measuring shaft 14 is connected to the input shaft of the one-in-two-out gearbox 15. The first output shaft of the gearbox 15 is connected to the shaft of the first coupling 16 and the asynchronous generator 18. The second output shaft of the gearbox 15 is connected to the shaft of the second coupling 17 and the hydraulic dynamometer 19. The speed of the motor 11 is 600 r / min. The maximum speed of the hydraulic dynamometer 19 is 600 r / min, and the actual optimal operating speed is 500 r / min. The speed of the asynchronous generator 18 is 1500 r / min. The reduction ratio between the input shaft and the first output shaft of the gearbox 15 is 1:1.2, and the reduction ratio between the input shaft and the second output shaft is 1:2.5.

[0036] The rectifier power supply 22 provides main power to the inverter under test 20. The inverter under test 20 drives the motor 11 to rotate. The motor 11, driven by the inverter under test 20, converts electrical energy into mechanical energy. Part of this mechanical energy is converted into heat energy and consumed by the hydraulic dynamometer 19, also known as the energy consumption load. The other part serves as the load for the four-quadrant inverter 23, where the mechanical energy is converted into electrical energy by the asynchronous generator 18, rectified by the four-quadrant inverter 23, and fed back to the DC bus, also known as the feedback load. In the high-power test project, the load consists of the energy consumption load and the feedback load connected in parallel, namely, the hydraulic dynamometer and the four-quadrant load. The four-quadrant load consists of the four-quadrant inverter 23 and the asynchronous generator 18. The motor should be started to a lower speed first, and the hydraulic dynamometer load should be engaged in the test management system, followed by the four-quadrant load. The motor speed should be increased, and the hydraulic dynamometer and four-quadrant load should be increased to maintain a balance between the two loads. In low-to-medium power operation tests, hydraulic dynamometers are preferred as loads due to their ease of operation and limited energy savings. When conducting speed and power mode switching tests, hydraulic dynamometers are the preferred load, and they are initially set to constant torque mode.

[0037] Reference Figure 3 As shown, the electrical equipment includes a DC bus for parallel connection with the frequency converter under test 20, the rectifier power supply 22, and the four-quadrant frequency converter 23, and an incoming line transformer 21 connected to the rectifier power supply 22. The four-quadrant frequency converter 23 is connected to the asynchronous generator 18. The incoming line transformer 21, the rectifier power supply 22, the asynchronous generator 18, and the four-quadrant frequency converter 23 constitute the main electrical equipment of the test load. The DC bus of the rectifier power supply 22, the frequency converter under test 20, and the four-quadrant frequency converter 23 are connected in parallel.

[0038] During the sudden load increase and decrease test, in order to ensure the stable and reliable DC bus voltage, an energy-consuming resistor 4 is connected in parallel on the DC bus to stabilize the DC bus voltage during the sudden load increase and decrease test.

[0039] To collect and monitor the DC voltage and current of the inverter under test 20, the AC input voltage and current of the motor 11, and the speed, torque, and power of the motor 11 in real time, a measurement system is deployed. The measurement system includes a torque measuring instrument 31, voltage / current sensors 32 respectively installed on the inverter under test 20 and the four-quadrant inverter 23, and field acquisition modules 33 respectively connected to the voltage / current sensors 32, the inverter under test 20 and the motor 11, the four-quadrant inverter 23 and the asynchronous generator 18. The multiple field acquisition modules 33 are connected to form a measurement device 34.

[0040] Figure 1 The test load shown is for a 5MW six-phase permanent magnet motor, consisting of a 2.5MW hydraulic dynamometer and a 2.5MW four-quadrant load. Figure 3The motor shown is an AC 690V motor, the four-quadrant load is a three-phase AC 690V asynchronous motor, and the four-quadrant frequency converter is a 2.5MW frequency converter. Adjust the rectifier power supply output to make the DC side voltage a low-voltage DC 1000V. The DC side resistance is 5Ω. Set the overload protection threshold long delay of the motor-side DC switchgear to 6000A and the short-circuit protection threshold short delay to 10000A. Set the overload protection threshold long delay of the four-quadrant load-side switchgear to 3000A and the short-circuit protection threshold short delay to 5000A.

[0041] Reference Figure 4 As shown, to centrally operate and manage the electrical equipment of the test load, this invention also includes a test management system. This system centrally controls the electrical equipment and auxiliary equipment, and implements interlocking protection between the tested inverter 20 and the motor 11. It also controls the cooling system, shaft oil supply equipment (lubricating oil system), hydraulic dynamometer 19 control equipment, and auxiliary power supply. Auxiliary equipment refers to the cooling system, lubricating oil system, and hydraulic dynamometer control console. To ensure test safety, interlocking protection is established between the tested inverter 20 and motor 11 and the test load. An emergency stop interlocking protection is installed in the test management system. The test management system also monitors and manages the cooling system and controls the start and stop of the water pump, monitors the shaft oil supply equipment and lubricating oil system and controls the start and stop of the lubricating oil pump, and manages and controls the hydraulic dynamometer control equipment, auxiliary power supply, and other auxiliary electrical equipment.

[0042] The embodiments of this invention can also be used for testing 3MW-class AC 380V motors. The shaft system is matched to the motor in height and coupling. The four-quadrant load asynchronous motor is set to operate in field-weakening mode. The rectified power supply output voltage is controlled to DC 550V.

[0043] The hydraulic dynamometer and asynchronous generator in this patent application are connected in parallel via a gearbox, which is completely different from the technical solution of Chinese Patent CN117369549A. The power distribution method in this patent application is also different, and a further difference lies in the control method. The purpose and effect of the motor load in this patent application are completely different from those of Chinese Patent CN109696592A. The technical solution and effect of this patent application are also different from those of Chinese Patents CN115832689A and CN120629928A.

[0044] The scope of protection of the claims of this invention is not limited to the embodiments described above. Those skilled in the art can make various adjustments and improvements without departing from the inventive concept of this invention, and these all fall within the scope of protection of this invention.

Claims

1. A test system for a motor with electromechanical hybrid energy feedback capability, characterized in that: It includes a flexible coupling (12) for connecting to the output of the motor under test (11), the flexible coupling (12) being connected to the asynchronous generator (18) and the hydraulic dynamometer (19) respectively via a gearbox (15); it also includes a DC bus for parallel connection with the frequency converter under test (20), the rectifier power supply (22), and the four-quadrant frequency converter (23), and an incoming line transformer (21) connected to the rectifier power supply (22), the four-quadrant frequency converter (23) being connected to the asynchronous generator (18); it also includes a voltage / current sensor (32) installed on the four-quadrant frequency converter (23) and a voltage / current sensor connected to it respectively. (32) Field acquisition module (33) of four-quadrant frequency converter (23) and asynchronous generator (18), wherein the field acquisition module (33) is connected to a measuring device (34) consisting of a power analyzer, a centralized storage and display system; during high-power tests, the hydraulic dynamometer (19) and the four-quadrant load consisting of the four-quadrant frequency converter (23) and the asynchronous generator (18) are simultaneously put into operation, and the load of the two is kept balanced; during medium and low power tests, the hydraulic dynamometer (19) is used as the load first; during speed and power mode switching tests, the hydraulic dynamometer (19) is used first and set to constant torque mode.

2. The electromechanical hybrid energy feedback motor testing system according to claim 1, characterized in that, A support bearing (13) is provided between the flexible coupling (12) and the gearbox (15).

3. The electromechanical hybrid energy feedback motor testing system according to claim 2, characterized in that, A torque measuring shaft (14) is connected between the support bearing (13) and the gearbox (15), and a torque measuring instrument (31) is connected to the torque measuring shaft (13).

4. A test system for a motor with electromechanical hybrid energy feedback according to claim 1, 2, or 3, characterized in that, The DC input side of the tested frequency converter (20) and the DC output side of the four-quadrant frequency converter (23) are respectively equipped with switch cabinets.

5. The electromechanical hybrid energy feedback motor testing system according to claim 4, characterized in that, The energy-consuming resistor (4) is connected in parallel on the DC bus.

6. The electromechanical hybrid energy feedback motor testing system according to claim 5, characterized in that, The gearbox (15) is a one-in-two-out gearbox, with a reduction ratio of 1:1.2 between the input shaft and the first output shaft, and a reduction ratio of 1:2.5 between the input shaft and the second output shaft.

Images