Self-checking method and output system of dynamic braking device

Abstract

The invention discloses an energy consumption braking device self-checking method and an output system, and relates to the technical field of detection, and the method comprises the steps: starting a frequency converter in response to a starting instruction, and obtaining a first output current value and a second output current value of the frequency converter in a first phase sequence and a second phase sequence respectively in a first state that an energy consumption braking resistor is not connected to a circuit; if the first output current value and the second output current value meet the preset output current condition, in the second state that the energy consumption braking resistor is connected into the circuit, a third output current value and a fourth output current value of the frequency converter in the first phase sequence and the second phase sequence are obtained respectively, and whether the connection state of the energy consumption braking resistor is normal or not is judged; if yes, the output system is allowed to be normally started; and if not, generating and outputting fault prompt information. Safety accidents caused by the fact that energy cannot be released due to abnormal shutdown can be fundamentally avoided, and the intrinsic safety level and operation reliability of equipment are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of detection technology, and in particular to a self-testing method and output system for an energy-consuming braking device. Background Technology

[0002] In surface oil extraction operations, screw pumps are a widely used and critical piece of equipment, and their operational safety and reliability are of paramount importance. The operation of a screw pump mainly includes two stages: startup and shutdown. During startup, the motor drives the sucker rod to rotate forward, lifting the crude oil from the well to the surface and transporting it through pipelines. During shutdown, due to the significant elastic deformation characteristics of the sucker rod string and the potential backflow of fluid within the tubing under gravity, the system accumulates a large amount of elastic potential energy and fluid potential energy. If this energy is not effectively controlled, it can cause the sucker rod to rotate uncontrollably in the reverse direction at high speed during shutdown, potentially leading to serious safety accidents such as sucker rod disengagement.

[0003] To ensure safety during shutdown, existing technologies typically employ energy-dissipating braking devices. These devices convert the aforementioned energy into electrical energy and dissipate it as heat through an energy-dissipating braking resistor, thereby achieving smooth control of the shutdown speed. This energy-dissipating braking resistor is particularly critical under abnormal shutdown conditions (such as sudden inverter failure or external power outages), as its reliable connection directly determines whether the system can safely dissipate energy. However, in actual operating environments, the energy-dissipating braking resistor and its connecting lines may experience abnormal states such as open circuits or short circuits due to vibration, aging, or external interference. Once the energy-dissipating braking resistor malfunctions, the accumulated energy cannot be effectively released during abnormal shutdowns, directly threatening the safety of equipment and personnel. Summary of the Invention

[0004] This invention provides a self-testing method and output system for an energy-consuming braking device. The technical problem it aims to solve is: how to effectively detect the connection status of the energy-consuming braking resistor before starting the screw pump system, so as to avoid the safety hazards caused by starting the system under abnormal conditions of the energy-consuming braking resistor.

[0005] In a first aspect, embodiments of the present invention provide a self-testing method for an energy-saving braking device, wherein the output system includes a frequency converter, a motor winding, and an energy-saving braking resistor, and the method includes:

[0006] In response to the start command, the inverter is started. In the first state where the energy consumption braking resistor is not connected to the circuit, the first output current value and the second output current value of the inverter under the preset first phase sequence and the preset second phase sequence are respectively obtained.

[0007] If the first output current value and the second output current value meet the preset output current conditions, in the second state of the energy consumption braking resistor connected to the circuit, the third output current value and the fourth output current value of the inverter under the preset first phase sequence and the preset second phase sequence are obtained respectively.

[0008] Based on the third and fourth output current values, determine whether the connection status of the energy-consuming braking resistor is normal.

[0009] If the connection status of the energy-consuming braking resistor is normal, the output system is allowed to start normally;

[0010] If the connection status of the energy-consuming braking resistor is abnormal, a fault prompt message will be generated and output.

[0011] Optionally, determining whether the connection status of the energy-consuming braking resistor is normal based on the third output current value and the fourth output current value includes:

[0012] If the third output current value is within the first preset range and the fourth output current value is within the second preset range, the connection status of the energy-consuming braking resistor is determined to be normal.

[0013] If the third output current value is not within the first preset range, or / and the fourth output current value is not within the second preset range, the connection status of the energy-consuming braking resistor is determined to be abnormal.

[0014] Optionally, the first preset range is determined based on a preset first reference current value; the second preset range is determined based on a preset second reference current value.

[0015] Optionally, the first reference current value and the second reference current value are obtained through a self-learning step, the self-learning step including:

[0016] During initial power-on or commissioning, the inverter is controlled to output the detection current of the first phase sequence and the second phase sequence respectively in the second state with a preset target output voltage;

[0017] The current value measured under the first phase sequence is collected and recorded as the first reference current value, and the current value measured under the second phase sequence is recorded as the second reference current value.

[0018] Optionally, obtaining the third and fourth output current values ​​of the frequency converter under a preset first phase sequence and a preset second phase sequence respectively includes:

[0019] In the second state, and when the frequency converter is in the first phase sequence, the output of the frequency converter is controlled to be a preset target output voltage, and the third output current value is collected;

[0020] In the second state, and when the frequency converter is in the second phase sequence, the output of the frequency converter is controlled to be a preset target output voltage, and the fourth output current value is collected.

[0021] Optionally, obtaining the first output current value and the second output current value of the frequency converter under a preset first phase sequence and a preset second phase sequence respectively includes:

[0022] In the first state, and when the frequency converter is in the first phase sequence, the output of the frequency converter is controlled to be a preset target output voltage, and the first output current value is collected;

[0023] In the first state, and when the frequency converter is in the second phase sequence, the output of the frequency converter is controlled to be a preset target output voltage, and the second output current value is collected.

[0024] Optionally, generating and outputting fault prompt information includes:

[0025] If the third output current value is not within the first preset range, a fault prompt message is generated and output to indicate that the first phase sequence is abnormal;

[0026] If the fourth output current value is not within the second preset range, a fault prompt message is generated and output to indicate that the second phase sequence is abnormal;

[0027] If the third output current value is not within the first preset range and the fourth output current value is not within the second preset range, a fault prompt message is generated and output to indicate that both the first phase sequence and the second phase sequence are abnormal.

[0028] Optionally, the method further includes:

[0029] If the first output current value and the second output current value do not meet the preset output current conditions, an abnormal prompt message will be generated.

[0030] In a second aspect, embodiments of the present invention provide an output system for performing the method described in the first aspect, comprising: a frequency converter, a motor winding, an energy-consuming braking resistor, a first contactor, a second contactor, and a control circuit;

[0031] The control circuit includes a start button and a first relay. The start button is configured to trigger the first relay to engage. The normally open contact of the first relay is connected between the start control terminal and the common terminal of the frequency converter.

[0032] The main contacts of the first contactor are connected in series between the output terminal of the frequency converter and the motor winding;

[0033] The main contacts of the second contactor are connected in series between the energy-consuming braking resistor and the output terminal of the frequency converter.

[0034] Optionally, the auxiliary status feedback contact of the second contactor is connected to the status feedback terminal of the frequency converter to provide feedback to the frequency converter on the engagement or disengagement status of the second contactor.

[0035] This invention provides a self-testing method and output system for an energy-saving braking device. The method includes: responding to a start command, starting the frequency converter; in a first state where the energy-saving braking resistor is not connected to the circuit, acquiring a first output current value and a second output current value of the frequency converter under preset first and second phase sequences, respectively; if the first and second output current values ​​meet preset output current conditions, in a second state where the energy-saving braking resistor is connected to the circuit, acquiring a third and a fourth output current value of the frequency converter under preset first and second phase sequences, respectively; based on the third and fourth output current values, determining whether the connection status of the energy-saving braking resistor is normal; if the connection status of the energy-saving braking resistor is normal, allowing the output system to start normally; if the connection status of the energy-saving braking resistor is abnormal, generating and outputting a fault indication message. This invention proactively verifies the status of the energy-saving braking resistor before the screw pump starts through a multi-stage detection process. First, a baseline is established by testing the motor circuit when the energy-consuming braking resistor is not connected. Then, after the energy-consuming braking resistor is connected, the current change is measured. Through comparative analysis, anomalies such as open circuits and short circuits in the energy-consuming braking resistor are accurately diagnosed. This method prioritizes safety verification, forming an automated safety interlock mechanism that effectively prevents the system from starting when the braking function fails. It fundamentally avoids safety accidents caused by the inability to release energy due to abnormal shutdown, significantly improving the inherent safety level and operational reliability of the equipment. Attached Figure Description

[0036] 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.

[0037] Figure 1 A flowchart illustrating a self-testing method for an energy-consuming braking device provided in an embodiment of the present invention;

[0038] Figure 2A circuit block diagram of a screw pump system provided in an embodiment of the present invention;

[0039] Figure 3 This is a circuit diagram of a frequency converter provided in an embodiment of the present invention;

[0040] Figure 4 A circuit diagram of the control loop of a frequency converter provided for an embodiment of the invention. Detailed Implementation

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] As used in this specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrases "if determined" or "if [described condition or event] is detected" may be interpreted, depending on the context, as "once determined," "in response to determination," "once [described condition or event] is detected," or "in response to detection of [described condition or event]."

[0046] See Figures 2-4This invention provides an output system for executing a self-testing method for an energy-consuming braking device, comprising: a frequency converter M, a motor winding M, energy-consuming braking resistors R1, R2 and R3, a first contactor KM1, a second contactor KM2 and a control circuit.

[0047] The control circuit includes a start button SB2 and a first relay K1. The start button SB2 is configured to trigger the first relay K1 to close. The normally open contact of the first relay K1 is connected between the start control terminal X1 of the frequency converter and the common terminal COM.

[0048] The main contacts of the first contactor KM1 are connected in series between the output terminal of the frequency converter and the motor winding.

[0049] The main contacts of the second contactor KM2 are connected in series between the energy-consuming braking resistor and the output terminal of the frequency converter.

[0050] Furthermore, the auxiliary status feedback contact of the second contactor KM2 is connected to the status feedback terminal X2 of the frequency converter, and is used to provide feedback to the frequency converter on the engaged or disengaged status of the second contactor KM2.

[0051] Please see Figure 1 The present invention provides a self-testing method for an energy-saving braking device, see [link to relevant documentation]. Figures 2-4 The output system, such as a screw pump system, includes a frequency converter, motor windings M, and energy-consuming braking resistors R1, R2, and R3. The method includes the following steps:

[0052] S1, in response to the start command, start the frequency converter, and in the first state where the energy consumption braking resistor is not connected to the circuit, obtain the first output current value and the second output current value of the frequency converter under the preset first phase sequence and the preset second phase sequence, respectively.

[0053] In practice, a preliminary inspection of the motor windings and their connecting circuits was conducted. Since the motor winding impedance is relatively stable, the current values ​​measured for different phase sequences should exhibit expected consistency under the same test voltage. This preliminary inspection effectively identifies major connection faults on the motor side, such as open circuits or severe phase imbalances. This prevents subsequent tests on the energy-consuming braking resistor from being based on an incorrect foundation when the main circuit itself is faulty, leading to misjudgments or missed detections. Therefore, it provides a clean and reliable data reference starting point for the entire self-test process.

[0054] In some preferred embodiments, the above step of "obtaining the first output current value and the second output current value of the frequency converter under the preset first phase sequence and the preset second phase sequence respectively" specifically includes the following steps: in the first state and when the frequency converter is in the first phase sequence, controlling the output of the frequency converter to a preset target output voltage and collecting the first output current value; in the first state and when the frequency converter is in the second phase sequence, controlling the output of the frequency converter to a preset target output voltage and collecting the second output current value.

[0055] In practice, maintaining the output voltage at the preset target output voltage is crucial for accurate measurement when testing the motor windings in the first state. The motor windings can be considered a composite load of inductive and resistive forces, but under specific low-frequency, low-voltage test conditions, their current response is primarily affected by DC resistance. By applying the preset target output voltage in both phase sequences, it can be expected that, assuming the motor windings are symmetrical and properly connected, the measured first and second output current values ​​should be similar. If the output voltage fluctuates, it becomes impossible to determine whether the current difference stems from motor winding asymmetry or from unstable detection voltage.

[0056] For example, in one embodiment, the first phase sequence is the UV phase sequence and the second phase sequence is the UW phase sequence, see [link to relevant documentation]. Figure 2 The first contactor KM1 is closed, and the second contactor KM2 is opened. The energy-consuming braking resistors R1, R2, and R3 are not connected to the circuit. The first switch VT1 and the fifth switch VT5 are turned on, and the second switch VT2, the third switch VT3, the fourth switch VT4, and the sixth switch VT6 are turned off. By adjusting the duty cycle of the first switch VT1 and / or the fifth switch VT5, the output voltage is made to the target output voltage. At this time, the first output current value is measured, and the duty cycle is recorded. In this embodiment of the invention, the first output current value is 10%-30% of the rated current, wherein it is 20%-30% for small-power motors and 10%-20% for large-power motors.

[0057] Further, the first contactor KM1 is closed, and the second contactor KM2 is opened, so the energy-consuming braking resistors R1, R2, and R3 are not connected to the circuit; the first switch VT1 and the sixth switch VT6 are turned on, and the second switch VT2, the third switch VT3, the fourth switch VT4, and the fifth switch VT5 are turned off. By adjusting the duty cycle of the first switch VT1 and / or the sixth switch VT6, the output voltage is made to the target output voltage. At this time, the second output current value is measured, and the duty cycle is recorded. In this embodiment of the invention, the second output current value is 10%-30% of the rated current, of which 20%-30% is for small-power motors and 10%-20% is for large-power motors.

[0058] S2, if the first output current value and the second output current value meet the preset output current conditions, in the second state of the energy consumption braking resistor connected to the circuit, the third output current value and the fourth output current value of the frequency converter under the preset first phase sequence and the preset second phase sequence are obtained respectively.

[0059] In practice, if the first output current value and the second output current value meet a preset output current condition, it indicates that the motor winding is fault-free. Specifically, the output current condition can be defined as follows: the absolute value of the difference between the first output current value and the second output current value is less than a preset current threshold.

[0060] Furthermore, by actively controlling the contactor's operation and altering the circuit topology, the energy-consuming braking resistor is connected to the test circuit, and current measurements are performed again under different phase sequences. The changes in the obtained current values ​​are primarily attributed to the connection of the energy-consuming braking resistor. If the energy-consuming braking resistor is properly connected and its resistance is normal, the measured current will match the expected value based on circuit theory. If the energy-consuming braking resistor is open-circuited, the current will significantly decrease or even disappear; if the energy-consuming braking resistor is short-circuited, the current will abnormally increase. This method, through state switching and comparative measurement, allows the method to specifically capture changes in circuit parameters caused by changes in the state of the energy-consuming braking resistor itself, greatly improving the targeting and accuracy of fault detection.

[0061] In some preferred embodiments, the method further includes: generating an abnormal prompt message if the first output current value and the second output current value do not meet a preset output current condition.

[0062] In practical implementation, a pre-emptive check of the motor winding connection status is added. When the first and second output current values ​​do not meet preset conditions, an abnormality warning message is output, expanding the diagnostic scope of the self-test system and preventing misjudgments. If the motor circuit itself has connection abnormalities such as open circuits, short circuits, or severe asymmetry, any energy-consuming braking resistor status detection based on this will be meaningless, and its conclusions will be unreliable. This embodiment is equivalent to performing a system-level "self-test" before detecting the energy-consuming braking resistor. It can detect and report faults on the motor side in advance, thereby stopping subsequent unnecessary or ineffective testing processes.

[0063] In some preferred embodiments, the above step of "obtaining the third output current value and the fourth output current value of the frequency converter under the preset first phase sequence and the preset second phase sequence respectively" specifically includes the following steps: in the second state and when the frequency converter is in the first phase sequence, controlling the output of the frequency converter to a preset target output voltage and collecting the third output current value; in the second state and when the frequency converter is in the second phase sequence, controlling the output of the frequency converter to a preset target output voltage and collecting the fourth output current value.

[0064] In practical implementation, according to Ohm's law, in a purely resistive circuit, the current flowing through a resistor is directly proportional to the voltage applied across the resistor. When testing the energy-consuming braking resistor, if the applied voltage is different each time it is tested, the difference in the measured current value may stem from voltage changes rather than changes in the resistor's own state, leading to inaccurate judgments. By strictly controlling the inverter to output a preset target output voltage under two different phase sequences, the variable of "voltage" is effectively fixed. Under this premise, any significant difference between the measured third and fourth output current values ​​can be uniquely and accurately attributed to the connection state or resistance change of the energy-consuming braking resistor in that phase sequence circuit. This eliminates errors introduced by inconsistent testing conditions, thereby ensuring the scientific nature of the entire self-testing process and the accuracy of the results.

[0065] For example, in one embodiment, the first phase sequence is the UV phase sequence and the second phase sequence is the UW phase sequence, see [link to relevant documentation]. Figure 2 Close the first contactor KM1 and the second contactor KM2, and connect the energy-consuming braking resistors R1, R2 and R3 to the circuit; turn on the first switch VT1 and the fifth switch VT5, and turn off the second switch VT2, the third switch VT3, the fourth switch VT4 and the sixth switch VT6. By adjusting the duty cycle of the first switch VT1 and / or the fifth switch VT5, the output voltage is made to the target output voltage. At this time, the third output current value is measured, and the duty cycle at this time is recorded.

[0066] Further, the first contactor KM1 and the second contactor KM2 are closed, and the energy-consuming braking resistors R1, R2 and R3 are connected to the circuit; the first switch VT1 and the sixth switch VT6 are turned on, and the second switch VT2, the third switch VT3, the fourth switch VT4 and the fifth switch VT5 are turned off. By adjusting the duty cycle of the first switch VT1 and / or the sixth switch VT6, the output voltage is made to the target output voltage. At this time, the fourth output current value is measured, and the duty cycle at this time is recorded.

[0067] S3. Based on the third output current value and the fourth output current value, determine whether the connection status of the energy-consuming braking resistor is normal.

[0068] In practice, the real-time collected third and fourth output current values ​​are compared with preset normal current values ​​to make an objective binary decision of "normal" or "abnormal". This makes the judgment criteria uniform and reproducible, significantly improving the efficiency and reliability of the detection.

[0069] In some preferred embodiments, the above step "determining whether the connection status of the energy-consuming braking resistor is normal based on the third output current value and the fourth output current value" specifically includes the following steps: if the third output current value is within a first preset range and the fourth output current value is within a second preset range, the connection status of the energy-consuming braking resistor is determined to be normal; if the third output current value is not within the first preset range and / or the fourth output current value is not within the second preset range, the connection status of the energy-consuming braking resistor is determined to be abnormal.

[0070] In specific implementation, the logic for determining whether the connection status of the energy-consuming braking resistor is normal is clarified. This is achieved by comparing the measured third and fourth output current values ​​with the first and second preset ranges, respectively, thus improving the accuracy and automation level of the status judgment. This embodiment of the invention employs a clear and quantifiable judgment standard. By setting a reasonable current fluctuation range rather than a single fixed threshold, it can effectively distinguish between normal system fluctuations and true fault states. For example, when the resistor is normal, due to minor fluctuations in line impedance, contact resistance, and power supply voltage, the current value will vary within a reasonable range. This method allows for such normal fluctuations and avoids false alarms. Conversely, when the resistor is open-circuited, the current will be significantly lower than the lower limit of the range or even zero; when a short circuit occurs, the current will far exceed the upper limit of the range. This judgment logic based on preset ranges makes the fault diagnosis process more objective and reliable, greatly reducing the possibility of misjudgment and missed judgment, thereby further enhancing the accuracy and reliability of the self-testing system.

[0071] In some preferred embodiments, the first preset range is determined based on a preset first reference current value; the second preset range is determined based on a preset second reference current value. For example, the lower limit of the first preset range is 80% of the preset first reference current value, and the upper limit of the first preset range is 120% of the first reference current value; the lower limit of the second preset range is 80% of the preset second reference current value, and the upper limit of the second preset range is 120% of the second reference current value.

[0072] In practical implementation, the lower and upper limits of the first and second preset ranges are set to 80% and 120% of the corresponding first and second reference current values, respectively. This greatly enhances the applicability and robustness of the self-testing method in actual industrial environments. In industrial production sites, fluctuations in grid voltage, changes in ambient temperature, and parameter drift of electronic components are common phenomena. If the set judgment range is too narrow, the system may frequently generate false alarms due to these normal slight fluctuations, affecting production continuity. Conversely, if the range is too wide, it may not be able to effectively detect early faults or minor anomalies. Setting the range to 80% to 120% of the reference value provides a suitable balance between detection sensitivity and anti-interference capability. It can capture current anomalies caused by significant changes in resistance (such as open circuits or severe short circuits) while ignoring small changes caused by fluctuations in normal operating conditions, ensuring the stability and reliability of the detection results.

[0073] The first and second reference current values ​​can be calibrated by actual measurement before the screw pump system leaves the factory, and this invention does not specifically limit this. The first and second reference current values ​​are obtained through a self-learning step, which includes: during initial power-on or commissioning, controlling the frequency converter in the second state to output the detection currents of the first phase sequence and the second phase sequence respectively with a preset target output voltage; collecting and recording the current value measured under the first phase sequence as the first reference current value, and the current value measured under the second phase sequence as the second reference current value. Further, the first and second reference current values ​​are stored in non-volatile memory.

[0074] Specifically, the first reference current value and the second reference current value are benchmark data acquired and stored by this method in self-learning mode. They represent the standard quantities of the output current values ​​measured by the energy-consuming braking resistor in the second state, corresponding to the first phase sequence and the second phase sequence, respectively, when the connection state is normal. Specifically, during the initial installation or commissioning of the system, the inverter is controlled to output a detection current to the energy-consuming braking resistor in the normal connection state using the target output voltage. At this time, the stable current value accurately measured in the first phase sequence is defined as the first reference current value, and the stable current value accurately measured in the second phase sequence is defined as the second reference current value. These two reference current values ​​are then permanently stored in non-volatile memory, forming a comparison benchmark for state judgment during subsequent normal operation. Its technical significance lies in providing a personalized and objective quantitative standard for judging whether the connection state of the energy-consuming braking resistor is normal. This allows subsequent detection to accurately diagnose whether there are any abnormalities deviating from the normal state by comparing the real-time measured third output current value with the first reference current value and the real-time measured fourth output current value with the second reference current value.

[0075] The first reference current value I3 satisfies the following calculation formula:

[0076]

[0077] U1 is the target output voltage, I1 is the first output current value, and R is the resistance value of each phase of the energy-consuming braking resistor.

[0078] The second reference current value I4 satisfies the following calculation formula:

[0079]

[0080] U1 is the target output voltage, I2 is the second output current value, and R is the resistance value of each phase of the energy-consuming braking resistor.

[0081] S4. If the connection status of the energy-consuming braking resistor is normal, the output system is allowed to start normally.

[0082] In practice, when the diagnostic results are normal, the screw pump is allowed to start, which means that before the start of formal operation, it has been confirmed that its most critical safety braking function is fully ready.

[0083] S5. If the connection status of the energy-consuming braking resistor is abnormal, a fault prompt message is generated and output.

[0084] In practice, when an anomaly is diagnosed, the system will not only prevent the startup to avoid the equipment from operating in a "sick" state, but also generate and output fault information to promptly alert operators. This allows maintenance personnel to be aware of the fault as soon as possible and to quickly locate and eliminate potential hazards based on the prompts, greatly shortening downtime and fundamentally preventing equipment damage or even safety accidents that may be caused by the failure of the energy consumption braking resistor during emergency shutdown.

[0085] In some preferred embodiments, the above step "generating and outputting fault prompt information" specifically includes the following steps: if the third output current value is not within a first preset range, generate and output fault prompt information indicating that the first phase sequence is abnormal; if the fourth output current value is not within a second preset range, generate and output fault prompt information indicating that the second phase sequence is abnormal; if the third output current value is not within the first preset range and the fourth output current value is not within the second preset range, generate and output fault prompt information indicating that both the first phase sequence and the second phase sequence are abnormal.

[0086] In practice, traditional simple fault alarms may only indicate "abnormal energy consumption braking system," requiring maintenance personnel to rely on experience or tools to conduct a comprehensive inspection of the entire braking circuit to pinpoint the specific fault, a time-consuming and labor-intensive process. However, this invention can pinpoint the fault to a specific phase sequence, such as "abnormal first phase sequence" or "abnormal second phase sequence." This provides maintenance personnel with clear fault location information. This precise fault indication function significantly shortens troubleshooting time, accelerates system recovery, reduces production losses caused by equipment downtime, and reduces over-reliance on the experience level of maintenance personnel, demonstrating the high level of intelligence and user-friendliness of this self-testing method.

[0087] This invention proposes a self-testing method for an energy-saving braking device, comprising: responding to a start command, starting the frequency converter; in a first state where the energy-saving braking resistor is not connected to the circuit, acquiring a first output current value and a second output current value of the frequency converter under preset first and second phase sequences, respectively; if the first and second output current values ​​meet preset output current conditions, in a second state where the energy-saving braking resistor is connected to the circuit, acquiring a third and a fourth output current value of the frequency converter under preset first and second phase sequences, respectively; based on the third and fourth output current values, determining whether the connection status of the energy-saving braking resistor is normal; if the connection status of the energy-saving braking resistor is normal, allowing the output system to start normally; if the connection status of the energy-saving braking resistor is abnormal, generating and outputting a fault prompt message. This invention proactively verifies the status of the energy-saving braking resistor before the screw pump starts through a multi-stage detection process. First, a benchmark is established by detecting the motor circuit when the energy-saving braking resistor is not connected; then, current changes are measured after the energy-saving braking resistor is connected, and abnormalities such as open circuits and short circuits of the energy-saving braking resistor are accurately diagnosed through comparative analysis. This method prioritizes safety verification, forming an automated safety interlock mechanism that effectively prevents the system from starting when the braking function fails. It fundamentally avoids safety accidents caused by the inability to release energy due to abnormal shutdown, significantly improving the inherent safety level and operational reliability of the equipment.

[0088] The steps in the method of this invention can be adjusted, merged, or reduced in order according to actual needs. The units in the device of this invention can be merged, divided, or reduced according to actual needs. Furthermore, the functional units in the various embodiments of this invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0089] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, a terminal, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention.

[0090] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0091] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Since these modifications and variations fall within the scope of the claims and their equivalents, this invention also intends to include these modifications and variations.

[0092] The above description is merely a specific embodiment 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 self-testing method for an energy-consuming braking device, characterized in that, The output system includes a frequency converter, motor windings, and an energy-consuming braking resistor; the method includes: In response to the start command, the inverter is started. In the first state where the energy consumption braking resistor is not connected to the circuit, the first output current value and the second output current value of the inverter under the preset first phase sequence and the preset second phase sequence are respectively obtained. If the first output current value and the second output current value meet the preset output current conditions, in the second state of the energy consumption braking resistor connected to the circuit, the third output current value and the fourth output current value of the frequency converter under the preset first phase sequence and the preset second phase sequence are obtained respectively. Based on the third and fourth output current values, determine whether the connection status of the energy-consuming braking resistor is normal. If the connection status of the energy-consuming braking resistor is normal, the output system is allowed to start normally; If the connection status of the energy-consuming braking resistor is abnormal, a fault prompt message will be generated and output.

2. The self-testing method for the energy-consuming braking device according to claim 1, characterized in that, The step of determining whether the connection status of the energy-consuming braking resistor is normal based on the third output current value and the fourth output current value includes: If the third output current value is within the first preset range and the fourth output current value is within the second preset range, the connection status of the energy-consuming braking resistor is determined to be normal. If the third output current value is not within the first preset range, or / and the fourth output current value is not within the second preset range, the connection status of the energy-consuming braking resistor is determined to be abnormal.

3. The self-testing method for the energy-consuming braking device according to claim 2, characterized in that, The first preset range is determined based on a preset first reference current value; the second preset range is determined based on a preset second reference current value.

4. The self-testing method for the energy-consuming braking device according to claim 3, characterized in that, The first reference current value and the second reference current value are obtained through a self-learning step, which includes: During initial power-on or commissioning, the inverter is controlled to output the detection current of the first phase sequence and the second phase sequence respectively in the second state with a preset target output voltage; The current value measured under the first phase sequence is collected and recorded as the first reference current value, and the current value measured under the second phase sequence is recorded as the second reference current value.

5. The self-testing method for the energy-consuming braking device according to claim 1, characterized in that, The step of obtaining the third and fourth output current values ​​of the frequency converter under preset first and second phase sequences respectively includes: In the second state, and when the frequency converter is in the first phase sequence, the output of the frequency converter is controlled to be a preset target output voltage, and the third output current value is collected; In the second state, and when the frequency converter is in the second phase sequence, the output of the frequency converter is controlled to be a preset target output voltage, and the fourth output current value is collected.

6. The self-testing method for the energy-consuming braking device according to claim 1, characterized in that, The step of obtaining the first output current value and the second output current value of the frequency converter under a preset first phase sequence and a preset second phase sequence respectively includes: In the first state, and when the frequency converter is in the first phase sequence, the output of the frequency converter is controlled to be a preset target output voltage, and the first output current value is collected; In the first state, and when the frequency converter is in the second phase sequence, the output of the frequency converter is controlled to be a preset target output voltage, and the second output current value is collected.

7. The self-testing method for the energy-consuming braking device according to claim 1, characterized in that, The generation and output of fault message information includes: If the third output current value is not within the first preset range, a fault prompt message is generated and output to indicate that the first phase sequence is abnormal; If the fourth output current value is not within the second preset range, a fault prompt message is generated and output to indicate that the second phase sequence is abnormal; If the third output current value is not within the first preset range and the fourth output current value is not within the second preset range, a fault prompt message is generated and output to indicate that both the first phase sequence and the second phase sequence are abnormal.

8. The self-testing method for the energy-consuming braking device according to claim 1, characterized in that, The method further includes: If the first output current value and the second output current value do not meet the preset output current conditions, an abnormal prompt message will be generated.

9. An output system, characterized in that, The device is used to perform the method as described in any one of claims 1-8, comprising: a frequency converter, a motor winding, an energy-consuming braking resistor, a first contactor, a second contactor, and a control circuit; The control circuit includes a start button and a first relay. The start button is configured to trigger the first relay to engage. The normally open contact of the first relay is connected between the start control terminal and the common terminal of the frequency converter. The main contacts of the first contactor are connected in series between the output terminal of the frequency converter and the motor winding; The main contacts of the second contactor are connected in series between the energy-consuming braking resistor and the output terminal of the frequency converter.

10. The output system according to claim 9, characterized in that, The auxiliary status feedback contact of the second contactor is connected to the status feedback terminal of the frequency converter, and is used to provide feedback to the frequency converter on the engagement or disengagement status of the second contactor.

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