Motor performance test system, device and method

Abstract

The invention discloses a motor performance test system, device and method, the motor performance test system effectively manages the flow of current between an inverter controller and a variable frequency motor by introducing a relay switch assembly comprising a control coil and at least one set of switch elements. Through connection of the variable-frequency power supply, the control coil can respond to power-on or power-off, so that the switching element is driven to be switched on or switched off, current is cut off in time, reverse voltage is prevented from being generated, it is ensured that an inverter IPM element is not damaged, and therefore the safety and stability of a system are greatly improved; and a more reliable solution is provided for motor performance testing.

Description

Technical Field

[0001] This invention relates to the field of motor performance testing technology, and in particular to a motor performance testing system, apparatus and method. Background Technology

[0002] Under current technological conditions, dynamometers are commonly used to test parameters such as efficiency, copper loss, and iron loss of variable frequency motors to evaluate their performance. During testing, the motor operates under the load of the dynamometer, especially when simulated load and reverse torque are applied, which may cause the motor to generate reverse torque and reverse current. These reverse currents, when passing through the inverter's IPM (Insulated Gate Bipolar Transistor Module), form reverse voltage, which can easily cause breakdown or damage to internal components of the inverter, seriously threatening the safety and stability of the entire testing system. Especially during abnormal motor shutdowns or commissioning, unsuppressed reverse voltage can cause irreversible damage to the inverter's IPM components, leading to frequent equipment failures, increased maintenance costs, and affecting test accuracy. Since the inverter IPM is the core component of the motor drive system, its reliability and safety are crucial to the normal operation of the entire testing platform. Therefore, effectively preventing reverse voltage from damaging the inverter has become a significant technical challenge for ensuring the safety of motor performance testing and improving equipment reliability. Summary of the Invention

[0003] The embodiments of the present invention provide a motor performance testing system, apparatus and method, which aims to solve the safety problem that reverse voltage can damage inverter IPM components when using a dynamometer to test the efficiency, copper loss, iron loss and other performance of motors in the prior art.

[0004] In a first aspect, the present invention provides a motor performance testing system, comprising: a torque application device; a variable frequency motor coaxially connected to the torque application device; an inverter controller electrically connected to the variable frequency motor; a relay switch assembly including a control coil and at least one set of switching elements, the switching elements being connected in series between the inverter controller and the variable frequency motor; and a variable frequency power supply connected to the inverter controller and the control coil; wherein the control coil, in response to the energization or de-energization of the variable frequency power supply, drives the switching elements to close or open.

[0005] Secondly, the present invention provides a motor performance testing device, including the motor performance testing system described above.

[0006] Thirdly, the present invention provides a method for testing motor performance, including the motor performance testing device or the motor performance testing system described above. The method includes: fixing the variable frequency motor and the torque application device coaxially, and connecting the switching element to the output terminal of the inverter controller and the three-phase windings of the variable frequency motor; starting the inverter controller to control the operation of the variable frequency motor, and gradually loading the torque to the target torque value through the torque application device to start the motor performance test; when the test is completed, disconnecting the control coil from the variable frequency power supply.

[0007] Compared with the prior art, the beneficial effects of the present invention are:

[0008] In the technical solution of this invention, by introducing a relay switch assembly, including a control coil and at least one set of switching elements, the flow of current between the inverter controller and the variable frequency motor is effectively managed. Through the connection of the variable frequency power supply, the control coil can respond to energization or de-energization, thereby driving the switching elements to close or open, promptly cutting off the current, preventing the generation of reverse voltage, and ensuring that the inverter IPM components are not damaged. This greatly improves the safety and stability of the system, providing a more reliable solution for motor performance testing. Attached Figure Description

[0009] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 This is a circuit diagram of the first embodiment of the motor performance testing system of the present invention;

[0011] Figure 2 This is a circuit diagram of a second embodiment of the motor performance testing system of the present invention;

[0012] Figure 3 This is a circuit diagram of the third embodiment of the motor performance testing system of the present invention;

[0013] Figure 4 This is a schematic diagram illustrating the steps of the motor performance testing method according to an embodiment of the present invention;

[0014] Figure label:

[0015] 20. Inverter controller; 21. Rectifier side; 22. Inverter side;

[0016] 30. Control coil; 31. Switching element; 321. Normally closed switch; 322. Manual emergency control switch; 323. NTC thermistor;

[0017] 40. Torque application device; 41. Coupling; 52. Motor;

[0018] 60. Variable frequency power supply. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0021] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0022] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0023] This invention addresses the safety issue of reverse voltage damaging inverter IPM components when using a dynamometer to test the efficiency, copper loss, and iron loss performance of a motor 52 in existing technologies. It provides a motor 52 performance testing system. (Refer to...) Figures 1 to 3The motor 52 performance testing system includes: a torque application device 40; a variable frequency motor 52 coaxially connected to the torque application device 40; an inverter controller 20 electrically connected to the variable frequency motor 52; a relay switch assembly including a control coil 30 and at least one set of switching elements 31, the switching elements 31 being connected in series between the inverter controller 20 and the variable frequency motor 52; and a variable frequency power supply 60 connected to the inverter controller 20 and the control coil 30. The control coil 30 responds to the energization or de-energization of the variable frequency power supply 60, driving the switching elements 31 to close or open. In this invention, the motor 52 performance testing system includes five main parts: a torque application device 40, a variable frequency motor 52, an inverter controller 20, a relay switch assembly, and a variable frequency power supply 60. The torque application device 40 is coaxially connected to the variable frequency motor 52 and is used to apply a predetermined torque during the test to simulate different operating conditions and obtain the performance parameters of the motor 52. The torque application device 40 can be a mechanical torque sensor or an electronic torque controller 20, depending on the test requirements and equipment conditions.

[0024] The variable frequency motor 52, as the object under test, is coaxially connected to the torque application device 40 to ensure accurate torque transmission. The control of the variable frequency motor 52 is achieved by the inverter controller 20, which is electrically connected to the variable frequency motor 52 and can adjust the speed and torque of the motor 52 to meet the requirements of different test conditions. The output terminal of the inverter controller 20 is directly connected to the input terminal of the variable frequency motor 52, and its control signal is adjusted by the subsequent relay switch assembly.

[0025] In this system, the relay switch assembly includes a control coil 30 and a set of series-connected switching elements 31. Specifically, the power supply circuit of the control coil 30 is located between the frequency converter 60 and the inverter controller 20, driving the switching elements 31 to close or open in response to the energization or de-energization of the frequency converter 60. The switching element 31 can be a normally open contact of an AC relay or a solid-state relay (SSR) to ensure fast response and high reliability. The main function of the relay switch is to open or close the circuit between the inverter controller 20 and the frequency converter motor 52 at different test stages, thereby controlling the start, stop, or protection state of the motor 52. Simultaneously, at least one normally closed switch 321 is connected in series with the control coil 30 in the power supply circuit of the control coil 30 for further control of the control coil 30.

[0026] The variable frequency power supply 60 provides a stable AC power supply and is connected to the control coil 30 of the inverter controller 20 and the relay switch assembly. The on / off state of the variable frequency power supply 60 is controlled by the current in the control coil 30. When the variable frequency power supply 60 is energized, the control coil 30 receives current, driving the relay switch element 31 to close, forming a closed loop, allowing the inverter controller 20 to output a drive signal to the variable frequency motor 52, achieving normal drive. Conversely, when the variable frequency power supply 60 is de-energized, there is no current in the control coil 30, the relay switch element 31 opens, disconnecting the inverter controller 20 from the variable frequency motor 52, thereby protecting the motor 52.

[0027] In terms of specific implementation details, the on / off state of the control coil 30 is controlled by the state of the frequency converter 60. To ensure system reliability, an overvoltage protection device or a current-limiting resistor can be added between the control coil 30 and the frequency converter 60 to prevent equipment damage caused by instantaneous voltage surges. The selection of the relay switch element 31 should consider its rated current and withstand voltage to ensure that it can withstand the current changes during the start-up and operation of the motor 52 during testing.

[0028] In actual operation, the test steps are as follows: First, start the inverter power supply 60 to provide energy to the control coil 30, which drives the relay switch to close, thereby connecting the output terminal of the inverter controller 20 to the inverter motor 52. The motor 52 then starts running for performance testing. During the test, the torque application device 40 works synchronously to apply different torques to the motor 52 to simulate various operating conditions. After the test, stop the power supply to the inverter power supply 60, and the relay switch immediately opens, disconnecting the inverter controller 20 from the inverter motor 52, stopping the motor 52 from running, and simultaneously preventing reverse voltage from damaging the motor 52 and the controller 20.

[0029] Furthermore, to enhance system reliability and scalability, the relay switch assembly incorporates multiple sets of switching elements 31 to achieve multi-stage protection control, such as implementing different disconnection strategies at different test stages or under fault conditions. A monitoring circuit can also be added to detect the relay switch status and current / voltage parameters in real time, automatically triggering alarms or switching protection measures. The system of this invention is equipped with a digital control module, utilizing a microcontroller 20 or PLC to intelligently monitor and adjust the relay switch status, enabling remote control and automated testing processes. The introduction of solid-state relays to replace mechanical relays can also be considered to reduce the risk of mechanical failure and improve switching speed and durability. In addition, combined with multi-channel control technology, multiple test units can be controlled simultaneously, improving testing efficiency.

[0030] In the technical solution of this invention, by introducing a relay switch assembly, including a control coil 30 and at least one set of switching elements 31, the flow of current between the inverter controller 20 and the variable frequency motor 52 is effectively managed. Through the connection of the variable frequency power supply 60, the control coil 30 can respond to energization or de-energization, thereby driving the switching elements 31 to close or open, promptly cutting off the current, preventing the generation of reverse voltage, and ensuring that the inverter IPM components are not damaged. This greatly improves the safety and stability of the system, providing a more reliable solution for the performance testing of the motor 52.

[0031] In one embodiment, reference is made to Figures 1 to 3 The switching element 31 closes with a power-on delay and opens instantaneously upon power-off. The switching element 31 is implemented using an AC relay or solid-state relay (SSR) with a time-delay characteristic in conjunction with a time-delay control circuit. Specifically, the control coil 30 is connected to the frequency converter 60 and responds to the on / off state of the frequency converter 60. When the frequency converter 60 is powered on, the control coil 30 immediately receives current, triggering the relay or solid-state relay to conduct. However, to achieve "power-on delayed closing," a time-delay circuit is introduced in the control circuit, such as using a transistor time-delay circuit, the time-delay function of the relay, or a time-delay program controlled by the microcontroller 20, to ensure that the relay switches and closes only after a certain delay time, thereby avoiding the impact of instantaneous large current surges on the system.

[0032] For instantaneous disconnection during power failure, the rapid disconnection characteristics of solid-state relays can be utilized. Mechanical AC relays typically have a fast disconnection speed and automatically disconnect instantly upon power failure, preventing residual current in the circuit from continuing to conduct. This ensures that the connection between the inverter controller 20 and the variable frequency motor 52 is quickly severed at the moment of power failure, preventing reverse voltage generation or reverse current flow that could damage the equipment. Specific implementation details include: adding a time delay circuit, such as an RC delay circuit or a delay program for the microcontroller 20, to ensure that the relay closes only after a set time following power-on, thus achieving "power-on delayed closing"; and during power failure, the mechanical structure or solid-state characteristics of the relay ensure that it can disconnect instantly without delay, achieving the goal of "instantaneous disconnection upon power failure".

[0033] In practice, users can adjust the delay time parameters according to the specific needs of the system. For example, different delay times can be set for the delay circuit controlled by the microcontroller 20 to adapt to different test scenarios. Furthermore, to ensure the safety and reliability of the system, it is recommended to add auxiliary measures such as overvoltage protection and filtering circuits to the circuit to avoid malfunctions or equipment damage caused by sudden voltage changes.

[0034] Specifically, the switching element 31 of the relay switch assembly adopts an AC contactor with power-on delay closing and power-off instantaneous opening characteristics. Its control coil 30 is directly connected in parallel to the output terminal of the frequency converter 60. When the system is powered on, after the control coil 30 is energized, the main contacts close after a delay of 0.5 to 1 second through the built-in mechanical damping device. This ensures that the inverter controller 20 completes initialization and establishes a stable DC bus voltage before connecting the motor 52 load, avoiding surge current impact. When the power is cut off at the end of the test, after the control coil 30 is de-energized, the main contacts are quickly opened within 10 milliseconds by the strong reaction spring inside the contactor. At this time, the reverse electromotive force generated by the inertial rotation of the motor 52 rotor is physically isolated and cannot form a circuit through the inverter side 22 IGBT module, thereby effectively preventing the IPM from being broken down. The delayed disconnection characteristic can be verified by a standard relay tester that its action time is no more than 15 milliseconds. In order to adapt to the needs of motors with different power 52, the delay time can be changed by adjusting the adjustable resistor in the control circuit. In special application scenarios, the mechanical contactor can be replaced with a solid-state relay with an RC delay circuit to achieve more precise 1-100 millisecond level delay control.

[0035] In one embodiment, reference is made to Figures 1 to 3 The inverter controller 20 includes a rectifier side 21 and an inverter side 22. The rectifier side 21 is connected to the variable frequency power supply 60, and the inverter side 22 has a three-phase output terminal, which is connected to the three-phase windings of the variable frequency motor 52. The main function of the rectifier side 21 is to rectify the AC input from the variable frequency power supply 60 into DC power to provide a stable DC voltage to the inverter side 22. The rectifier circuit can use a diode bridge rectifier circuit or a rectifier bridge; efficiency and reliability should be considered when selecting a specific scheme. The rectified DC power supply is then filtered, such as by a capacitor filter, to smooth the voltage and ensure that the inverter side 22 operates on a stable DC voltage basis.

[0036] The inverter side 22 employs a three-phase inverter circuit to convert DC power into three-phase AC power. This inverter circuit typically consists of six switching elements 31, such as IGBTs or MOSFETs, which regulate the voltage and frequency of the three-phase output terminals using control strategies such as space vector pulse width modulation. The three terminals of the three-phase output terminals are respectively connected to the three-phase windings of the variable frequency motor 52, ensuring that the motor 52 can adjust its speed and torque according to test requirements.

[0037] In its implementation, the control circuit of the inverter controller 20 is controlled by a microcontroller 20 or a digital signal processor, which can dynamically adjust the on-time of the inverter switch according to the input frequency and voltage commands to achieve precise frequency and amplitude control. This control strategy not only ensures the stable operation of the motor 52, but also provides good adjustment capabilities to meet the needs of different test scenarios.

[0038] Regarding the connection method, high-quality wires and connectors should be used at the three-phase output terminals of the inverter controller 20 to ensure the reliability and safety of the electrical connection. To avoid high-frequency noise interference, shielding measures can be taken for the connection lines, and a filter circuit should be added at the output terminal to reduce the impact of noise and harmonics on the system.

[0039] During system operation, after the inverter power supply 60 is powered on, the rectifier side 21 of the inverter controller 20 operates first, converting AC power to DC power. At this time, the control coil 30 of the relay switch assembly is simultaneously energized, but the switch element 31 has not yet closed due to its delay characteristic, and the inverter side 22 does not output power temporarily. After the DC bus voltage stabilizes and the switch element 31 closes after a delay, the inverter side 22 begins to output PWM waves to drive the motor 52. After the test is completed, the inverter power supply 60 is powered off, the switch element 31 opens instantaneously, and the inverter side 22 immediately stops outputting power. The back electromotive force generated by the inertial rotation of the motor 52 rotor is physically isolated by the switch element 31, preventing it from flowing back to the IPM module. In addition, to further protect the inverter controller 20, the DSP chip of the inverter controller 20 can detect whether the output phase sequence matches the motor 52. If there is an error, the switch element 31 is prevented from closing.

[0040] Specifically, the inverter controller 20 adopts a modular design. Its rectifier side 21 consists of a single-phase full-bridge rectifier circuit and a DC bus filter capacitor, which is directly connected to the output terminal of the frequency converter 60 through a copper bus. The inverter side 22 uses a three-phase full-bridge IPM module as the core power device, and its three-phase output terminals (U, V, W) are respectively connected through a cross-section of not less than 4mm². 2 The multi-strand copper core cable is connected to the corresponding contacts of the relay switch assembly. The U-phase output terminal is connected to the motor 52U1 winding via the U contact of the switch element 31, the V-phase output terminal is connected to the motor 52V1 winding via the V contact of the switch element 31, and the W-phase output terminal is connected to the motor 52W1 winding via the W contact of the switch element 31. Each phase circuit is connected in series with a fast-acting fuse for short-circuit protection. The DSP chip inside the inverter controller 20 monitors the three-phase output current in real time. When the phase imbalance exceeds 15% or the single-phase current exceeds 1.5 times the rated value, the protection circuit is immediately triggered to cut off the IPM drive signal. At the same time, the disconnection command is sent to the relay switch assembly through the optocoupler to ensure that the fault isolation is completed within 5ms.

[0041] In one embodiment, reference is made to Figures 1 to 3At least one of the aforementioned switching elements 31 is connected in series between the three-phase output terminals of the inverter side 22 and the three-phase windings of the variable frequency motor 52. In this embodiment, the series connection of the switching elements 31 is between the three-phase output terminals of the inverter controller 20 and the three-phase windings of the variable frequency motor 52. This means that a switching element 31 is connected in series on the output line of each phase, which can be implemented using an AC relay, a solid-state relay, or a high-speed switching transistor. Each switching element 31 is driven by a control coil 30 or a control signal, and is controlled to close or open in response to the on / off state of the variable frequency power supply 60. Through this series structure, the output of one or more phases can be disconnected when needed, thereby realizing the protection of the motor 52 or the adjustment of the test conditions.

[0042] In the specific implementation details, solid-state relays, characterized by fast response and high reliability, are used because they have advantages such as no moving mechanical parts, vibration resistance, arc resistance, and fast response speed, making them particularly suitable for applications involving frequent switching and high-frequency operation. The input terminal of each solid-state relay is connected to the microcontroller 20 or PLC to receive the control signal, and the output terminal is connected to the corresponding three-phase winding of the variable frequency motor 52. Changes in the control signal can quickly connect or disconnect the phase line, thereby enabling or disabling the power supply to a specific phase.

[0043] During operation, when it is necessary to protect the motor 52 or control the test process, the system can control the state of these switching elements 31. For example, at the start of the test, the control system closes all switching elements 31 to ensure normal three-phase power supply; at the end of the test or in case of an abnormality, the system can quickly disconnect one or more phases, cutting off the power supply to the motor 52, thereby preventing reverse current or overvoltage from damaging the inverter controller 20 and the motor 52. Simultaneously, the series switches can also be used to simulate phase loss faults or special test scenarios, enriching the content and methods of the test.

[0044] To ensure system safety and stability, overcurrent protection, short-circuit protection, and filtering measures are incorporated into the control circuit of each switching element 31 to prevent equipment damage or malfunction caused by sudden changes in instantaneous current. The circuit design also considers the voltage rating and rated current of the switches to ensure reliable operation within their operating voltage and current range. Furthermore, to improve system maintenance and monitoring capabilities, status feedback is introduced into the status detection circuit of each switching element 31, enabling the controller 20 to monitor the switch's operating status in real time or to achieve fault diagnosis and remote control through a remote monitoring system.

[0045] In one embodiment, reference is made to Figures 1 to 3A coupling 41 is provided between the variable frequency motor 52 and the torque application device 40. The relay switch assembly also includes an electric clutch, which is disposed in the coupling 41. The control coil 30 responds to the energization or de-energization of the variable frequency power supply 60, driving the electric clutch to close or open. In this embodiment, the variable frequency motor 52 and the torque application device 40 are connected by a coupling 41, which is used both to transmit torque and to achieve mechanical connection and disconnection. To control torque transmission at different test stages, an electric clutch is added to the relay switch assembly, which is disposed inside the coupling 41. The main function of the electric clutch is to close or open the coupling 41 according to changes in the control signal, thereby controlling the continuity or disconnection of torque transmission.

[0046] Specifically, the electric clutch is configured with a control coil 30, whose two ends are connected to the frequency converter 60. By energizing or de-energizing the frequency converter 60, the control coil 30 receives a corresponding current, driving the mechanical or electromagnetic structure of the electric clutch to close or open. When the frequency converter 60 is energized, the control coil 30 generates a magnetic field, driving the internal mechanical structure or electromagnet of the electric clutch, causing the coupling 41 to close, mechanically connecting the frequency converter motor 52 to the torque application device 40, ensuring effective torque transmission and initiating the performance test. Conversely, when the frequency converter 60 is de-energized, the control coil 30 loses power, and the mechanical or electromagnetic mechanism driving the electric clutch returns to the open state, thus disconnecting the frequency converter motor 52 from the torque application device 40 and stopping torque transmission. The core of this mechanism lies in the electric clutch's rapid response and reliable disconnection capability, ensuring precise control of torque transmission during the testing process. In specific designs, an electromagnetic clutch can be used, which is compact, has a fast response speed, and is reliable in operation. The electromagnet's coil is driven by the control coil 30 and connected to the frequency converter 60. It generates a magnetic field when the power is switched on and off, controlling the opening and closing of the mechanical clutch. To ensure operational safety and reliability, the electric clutch should also be equipped with overcurrent protection and temperature control devices to prevent overload or overheating.

[0047] In actual operation, when torque application is required or the test begins, the system controls the variable frequency power supply 60 to energize the control coil 30, driving the electric clutch to engage and connecting the variable frequency motor 52 to the torque application device 40, thus achieving torque transmission. After the test, the variable frequency power supply 60 is disconnected, and the electric clutch quickly disengages, breaking the torque transmission and avoiding unnecessary mechanical wear and energy waste. This allows for precise control of the testing process, ensuring the controllability and repeatability of test conditions.

[0048] Specifically, the variable frequency motor 52 and the torque application device 40 are coaxially connected via a flexible coupling 41. This coupling 41 integrates an electromagnetic clutch, whose excitation coil and control coil 30 are connected in parallel to the output of the variable frequency power supply 60. When the system is powered on, the control coil 30 is energized, causing the electromagnetic clutch to engage within 50ms, ensuring a rigid connection between the motor 52 shaft and the torque application device 40. At this time, the torque application device 40 can accurately simulate the load condition. When the test is completed and the power is cut off, the control coil 30 is de-energized, causing the electromagnetic clutch to disengage rapidly within 20ms. Simultaneously, the switching element 31 of the relay switch assembly is disconnected. Electrical connection achieves dual mechanical and electrical isolation. The rated torque of the electromagnetic clutch is selected based on 1.5 times the maximum torque of motor 52. The friction plates are made of sintered copper-based material to ensure a service life of more than 100,000 cycles. High-precision encoders are installed at both ends of the coupling 41 to monitor the alignment status of the shaft system in real time. When the radial deviation exceeds a certain threshold, the system alarm is automatically triggered. This implementation scheme not only solves the impact problem caused by mechanical braking in traditional testing systems, but also achieves continuous and controllable torque transmission from 0% to 100% by adjusting the clutch excitation current, providing a hardware foundation for the subsequent development of an intelligent load simulation system.

[0049] In one embodiment, reference is made to Figures 1 to 3 The motor 52 performance testing system also includes a torque protection controller 20. The coupling 41 is equipped with a torque sensor. The torque protection controller 20 is connected to the torque sensor and the control coil 30. The torque protection controller 20 is used to drive the electric clutch to disengage through the control coil 30 when the reverse torque is detected to exceed the threshold.

[0050] In this embodiment, a torque sensor is embedded inside the coupling 41, which can detect the magnitude of the torque transmitted through the coupling 41 in real time. The torque sensor can be a strain gauge torque sensor or other types of torque detection elements. Its output signal is transmitted to the torque protection controller 20 after passing through a signal conditioning circuit. The torque protection controller 20 is a specially designed control module with a threshold setting function, used to determine whether the detected torque signal exceeds a preset safety threshold.

[0051] When the torque protection controller 20 receives a signal from the torque sensor, if it detects that the reverse torque (i.e., the reverse torque) exceeds a set threshold, it immediately sends a control signal to drive the electric clutch's opening mechanism through the connected control coil 30. Specifically, the control signal output by the torque protection controller 20 passes through the drive circuit, exciting the control coil 30 to generate a magnetic field, thereby driving the electric clutch's mechanical structure or electromagnetic mechanism to disconnect the coupling 41, immediately interrupting the torque transmission path and preventing excessive reverse torque from damaging the variable frequency motor 52, the control system, or other equipment.

[0052] In practical implementation, the torque sensor signal transmission should use shielded wires or differential signal lines to reduce interference and ensure detection accuracy. The threshold setting of the torque protection controller 20 can be flexibly adjusted according to test requirements, such as through software parameter adjustment, to ensure effective protection under different operating conditions. The control coil 30 drive circuit should have overcurrent and overload protection to ensure the safety and reliability of the equipment under high instantaneous current conditions.

[0053] Specifically, the coupling 41 integrates a non-contact torque sensor, whose signal output is connected to the torque protection controller 20 via a shielded cable. The controller 20 monitors the reverse torque value of the transmission shaft system in real time. When the detected torque exceeds the preset threshold, it immediately outputs a control signal to the control coil 30 of the relay switch assembly, forcibly disengaging the electromagnetic clutch within 10ms. Simultaneously, it sends a fault code to the main control system via the RS485 interface. The torque protection controller 20 adopts a triple-redundant processing architecture, containing three independent processors that process sensor signals in parallel. A majority voting mechanism ensures the reliability of the protection action. The threshold parameters can be set in stages within the range of 5% to 200% of the rated torque via a touch screen and have a power-off memory function. The system also has a mechanical torque limiter as a last line of defense. When the electronic protection system fails, mechanical slippage can occur when the reverse torque reaches 150% of the rated value. This implementation scheme effectively solves the problem of shaft damage caused by sudden load changes during testing through an electronic-mechanical dual protection mechanism, providing a safety guarantee for the performance testing of the high-precision motor 52. At the same time, it can realize centralized monitoring of multiple test devices through an expanded CAN bus interface.

[0054] In one embodiment, reference is made to Figure 2A manual emergency control switch 322 is connected in series in the power supply circuit of the control coil 30. In this embodiment, to enhance the system's safety and emergency response capabilities, the manual emergency control switch 322 is designed to be connected in series in the power supply circuit of the control coil 30. Specifically, this switch can be a mechanical push-button switch or a disconnecting switch, installed on the power supply path of the control coil 30, allowing operators to quickly disconnect the power supply to the control coil 30 in an emergency, thereby immediately cutting off the drive current of the relay switch and achieving a rapid response to disconnect the coupling 41 or the protection device. Regarding the connection method, the positive terminal of the control coil 30 is connected to the output terminal of the frequency converter 60 through the manual emergency control switch 322, while the negative terminal is directly connected to the neutral or ground wire of the frequency converter 60. Under normal operating conditions, the manual emergency control switch 322 is closed, allowing the frequency converter power supply 60 to provide current to the control coil 30, causing the relay switch element 31 to energize. In an emergency, the operator can manually open the switch, immediately cutting off the power to the control coil 30, causing the relay switch to lose power and the mechanical or electromagnetic mechanism to quickly disconnect, thereby disconnecting the coupling 41 or activating the protection device. The design of this manual emergency control switch 322 should consider ease of operation and safety, using clearly marked buttons or handles to ensure that operators can quickly identify and operate it in an emergency. Furthermore, to prevent misoperation, a locking device or protective cover should be installed on the switch to ensure that it can only be operated with a clear intent.

[0055] In practical applications, this manual emergency control switch 322 can be used not only for emergency power outages but also as a manual control method during system debugging, maintenance, or special testing conditions. The operation is simple: during normal operation, the switch remains closed; in emergencies or maintenance situations, the operator can manually disconnect the switch to immediately cut off the power to the control coil 30, ensuring equipment safety.

[0056] Specifically, a red mushroom-shaped emergency stop switch is connected in series in the power supply circuit of the control coil 30. This switch adopts a mechanical self-locking structure and is directly installed in a prominent position on the test system operation panel. When an abnormal situation occurs during the test, the operator can quickly press the emergency stop switch to immediately cut off the power supply circuit of the control coil 30, causing all contacts of the relay switch assembly to be forcibly disconnected within a preset time. At the same time, the main circuit of the frequency converter power supply 60 is cut off through the auxiliary contacts, realizing the system's emergency power failure protection. The emergency stop switch needs to be reset by rotating the button clockwise and manually lifting it. The system can only be restarted after the operator confirms that the site is safe. The normally closed contact of the switch is also connected to the emergency stop input module of the PLC control system. After being triggered, the emergency stop status will be displayed on the HMI interface and the equipment operation authority will be locked, providing the test system with safety protection measures in accordance with the ISO13850 standard. At the same time, this design allows the selection of manual / automatic control mode through a bypass switch in the normal test process to meet the safety operation requirements of different test scenarios.

[0057] In one embodiment, reference is made to Figure 3 A negative temperature coefficient thermistor is connected in series in the power supply circuit of the control coil 30. In this embodiment, the negative temperature coefficient thermistor (NTC thermistor 323) is connected in series in the power supply circuit of the control coil 30 as a control element for delayed start. When the system is powered on, the current first flows through the NTC thermistor 323. Due to its negative temperature coefficient characteristics, the resistance of the NTC thermistor 323 is high when the circuit is first connected, which limits the current of the control coil 30, resulting in insufficient electromagnetic driving force of the control coil 30 and delaying its response time, thereby realizing the delayed start of the switching element 31. As time goes by, the current flows through the NTC thermistor 323, and the resistance gradually decreases until it reaches a stable state. At this time, the control coil 30 obtains sufficient current to drive the relay switch or electric clutch and other actuators to close or open, realizing normal start operation. The specific duration of this delay process can be adjusted by selecting different resistance values ​​of the NTC thermistor 323 or by adjusting circuit parameters, such as series resistance, compensation circuit, etc., to meet different test requirements. In circuit design, the rated resistance and temperature coefficient of the NTC thermistor 323 should be selected based on the specific delay time requirements. Typically, selecting a higher resistance NTC thermistor 323 can achieve a delay effect of several hundred milliseconds to several seconds. To ensure system safety, it is recommended to incorporate current-limiting protection and overheat protection measures into the design to prevent the thermistor from overheating or being damaged during prolonged operation.

[0058] In actual operation, during system startup, the current in control coil 30 is limited by the NTC thermistor 323, delaying the activation of the relay switch or electric clutch to ensure the system remains in a safe and stable state. As time progresses, the thermistor's resistance gradually decreases, and the current in control coil 30 gradually increases, ultimately achieving the required startup timing control. This solution is particularly suitable for applications requiring slow start or delayed protection, effectively preventing the impact of instantaneous high currents on the system.

[0059] Specifically, a negative temperature coefficient thermistor is connected in series in the power supply circuit of the control coil 30. This thermistor is encapsulated in epoxy resin and mounted close to the metal casing of the relay to achieve optimal heat conduction. When the system is initially powered on, the thermistor at room temperature exhibits a high resistance, limiting the starting current of the control coil 30 to a safe range. As current continues to flow, the thermistor's temperature rises, and its resistance rapidly drops to a low resistance state (below 0.5Ω) within a short time, allowing the control coil 30 to obtain sufficient operating current and engage, thereby driving the switching element 31 to complete the delayed closing. When the system is powered off, the thermistor cools rapidly due to the cessation of power, and its resistance rises again, ensuring the control coil 30 releases quickly. This solution achieves a delay function without additional control circuitry through physical characteristics, making it particularly suitable for industrial testing environments with electromagnetic interference. Furthermore, the delay time can be adjusted by selecting thermistors of different specifications, or the temperature-resistance curve can be optimized by connecting a fixed resistor in parallel, providing a reliable and cost-effective delay protection solution for the system.

[0060] This invention also provides a motor 52 performance testing device, which includes the motor 52 performance testing system described in the above embodiments. The frequency converter 60 is connected to the input terminal of the control cabinet via a three-phase four-wire cable. The control cabinet houses the inverter controller 20 and relay switch assembly. The testing platform adopts a modular design. The motor 52 mounting base and the torque application device 40 base are quickly positioned via a T-slot guide rail. A coupling 41 with an electromagnetic clutch is installed between them, and a torque sensor or mechanical torque limiter is integrated inside the coupling 41. A manual emergency control switch 322 and a touchscreen human-machine interface are installed on the control panel. A negative temperature coefficient thermistor is configured in the control circuit to achieve time-delay protection. This device organically integrates the above functional units to form a complete testing system that can meet the performance testing requirements of motors 52 of different specifications. It also reserves CAN bus and Ethernet interfaces for connecting to the factory MES system, enabling automatic data acquisition and remote monitoring.

[0061] This invention also provides a method for testing the performance of a motor 52, which is applicable to the motor 52 performance testing device described in the above embodiments or the system described in any of the above embodiments. (Refer to...) Figure 4The performance testing method for this motor 52 includes:

[0062] S110. Fix the variable frequency motor and the torque application device coaxially, and connect the switching element to the output terminal of the inverter controller and the three-phase winding of the variable frequency motor;

[0063] S120. Start the inverter controller to control the operation of the variable frequency motor, and gradually load the motor to the target torque value through the torque application device to start the motor performance test.

[0064] S130. When the test is completed, disconnect the control coil from the frequency converter.

[0065] First, the variable frequency motor 52 and the torque application device 40 are coaxially fixed together via a coupling 41. The coupling 41 not only serves as a mechanical connection but also incorporates a torque sensor to monitor torque changes in real time. The torque application device 40 is gradually loaded by the control system, with a target torque value preset before the test begins to simulate the performance parameters of the motor 52 under different operating conditions.

[0066] Subsequently, the inverter controller 20 is activated, enabling it to control the variable frequency motor 52 to start running. The inverter controller 20 outputs three-phase AC power according to preset frequency and voltage parameters, causing the motor 52 to operate at the required speed and torque. During this process, the torque application device 40 gradually increases the applied torque until the target torque value is reached. The system monitors torque changes in real time through a torque sensor to ensure the accuracy and stability of the loading process.

[0067] During testing, the system can collect multiple performance parameters, including the efficiency, copper loss, iron loss, and temperature rise of motor 52, providing a basis for subsequent analysis. At this stage, the system can also adjust frequency, voltage, and torque parameters according to testing requirements to achieve performance evaluation under multiple operating conditions and in multiple indicators.

[0068] Upon completion of the test, to ensure safety and equipment protection, the operator or automatic control system will disconnect the control coil 30 from the frequency converter 60. This step is achieved through the system's control circuitry. After the control coil 30 is de-energized, the relay switch or electric clutch quickly disconnects, cutting off the torque transmission path and stopping the motor 52. Simultaneously, the system can automatically activate a protection mechanism to prevent equipment damage caused by reverse voltage or overload.

[0069] In industries such as automobiles, new energy, robotics, and wind power, the motor 52 is a core power component, and its accurate performance evaluation is crucial. The motor 52 performance testing system, apparatus, and method of this invention can meet the performance testing needs of various industrial motors 52, improve the automation level and testing accuracy, and reduce labor costs.

[0070] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A motor performance testing system, characterized in that, include: Torque application device; A variable frequency motor is coaxially connected to the torque application device; The inverter controller is electrically connected to the variable frequency motor; A relay switch assembly includes a control coil and at least one set of switching elements connected in series between the inverter controller and the variable frequency motor; A variable frequency power supply is connected to the inverter controller and the control coil; The control coil responds to the energization or de-energization of the frequency converter power supply, driving the switching element to close or open.

2. The motor performance testing system according to claim 1, characterized in that, The inverter controller includes a rectifier side and an inverter side. The rectifier side is connected to the variable frequency power supply, and the inverter side is provided with a three-phase output terminal, which is connected to the three-phase winding of the variable frequency motor.

3. The motor performance testing system according to claim 2, characterized in that, At least one of the switching elements is connected in series between the three-phase output terminal on the inverter side and the three-phase winding of the variable frequency motor.

4. The motor performance testing system according to claim 1, characterized in that, A coupling is provided between the variable frequency motor and the torque application device. The relay switch assembly also includes an electric clutch, which is located in the coupling. The control coil responds to the energization or de-energization of the variable frequency power supply, driving the electric clutch to close or open.

5. The motor performance testing system according to claim 4, characterized in that, It also includes a torque protection controller, in which a torque sensor is provided within the coupling. The torque protection controller is connected to the torque sensor and the control coil. The torque protection controller is used to drive the electric clutch to disengage via the control coil when a reverse torque exceeding a threshold is detected.

6. The motor performance testing system according to claim 1, characterized in that, A manual emergency control switch is connected in series in the power supply circuit of the control coil.

7. The motor performance testing system according to claim 1, characterized in that, A negative temperature coefficient thermistor is connected in series in the power supply circuit of the control coil.

8. The motor performance testing system according to claim 1, characterized in that, The switching element closes with a power-on delay and opens instantaneously when the power is off.

9. A motor performance testing device, characterized in that, Includes the motor performance testing system as described in any one of claims 1 to 8.

10. A method for testing the performance of a motor, characterized in that, The method includes the motor performance testing apparatus as described in claim 9 or the motor performance testing system as described in any one of claims 1 to 8, wherein the method comprises: The variable frequency motor and the torque application device are fixed coaxially, and the switching element is connected to the output terminal of the inverter controller and the three-phase winding of the variable frequency motor. The inverter controller is started to control the operation of the variable frequency motor, and the motor performance test is started by gradually loading the torque to the target torque value through the torque application device. When the test is complete, disconnect the control coil from the frequency converter.

Images