Brake holding mechanism control method and device and electronic equipment

Abstract

The application discloses a brake holding mechanism control method and device and electronic equipment, and relates to the field of hoisting machinery. The method comprises adjusting the host machine operating parameter of a host frequency converter according to a received control instruction; when the host machine operating parameter meets the operation condition of the host brake holding mechanism, the state of the host brake holding mechanism is maintained, and an operation ready signal sent by a slave frequency converter is waited for; wherein, the operation ready signal represents that the slave machine operating parameter of the slave frequency converter meets the operation condition of the slave brake holding mechanism; after the operation ready signal is received, a control operation corresponding to the control instruction is performed on the host brake holding mechanism, and an operation instruction is sent to the slave frequency converter, so that the slave frequency converter performs a control operation on the slave brake holding mechanism. The application can achieve the technical effect of coordinated action of two brake holding mechanisms, improve the equipment operation efficiency and operation safety.

Description

Technical Field

[0001] This application relates to the field of lifting machinery, and in particular to a method, device and electronic equipment for controlling a brake mechanism. Background Technology

[0002] In the field of lifting machinery, high-power, heavy-load operations generally require equipment with strong driving capabilities and high operational reliability. Typically, two motors are used to drive the same load to enhance driving capacity. The two motors are controlled by a master frequency converter and a slave frequency converter, respectively, and coordinated operation is achieved through master-slave control. The master and slave frequency converters are each equipped with independent braking mechanisms, and each independently controls the opening and closing of its respective braking mechanism. However, due to differences in the actual operating conditions of the two motors and the mechanical characteristics of the braking mechanisms on both sides, it is difficult for the master and slave frequency converters to maintain synchronized control of their respective braking mechanisms. The side that moves first will bear or release the load first, leading to a mismatch in torque output or operating frequency between the two motors. This can cause production failures such as loose gripping and material leakage, affecting operational efficiency and equipment safety.

[0003] Therefore, how to provide a solution to the above-mentioned technical problems is a problem that needs to be solved by those skilled in the art. Summary of the Invention

[0004] The purpose of this application is to provide a brake mechanism control method, device, and electronic device to at least solve the technical problem that the actions of the two brake mechanisms are difficult to keep in sync when two motors drive the same load, resulting in inconsistent torque output or operating frequency of the two motors.

[0005] To address the aforementioned technical problems, this application provides a brake mechanism control method applied to a master frequency converter. The brake mechanism control method includes: adjusting the master operating parameters of the master frequency converter according to a received control command; maintaining the state of the master brake mechanism when the master operating parameters meet the operating conditions for the master brake mechanism, and waiting for an operation ready signal sent by the slave frequency converter; wherein, the operation ready signal indicates that the slave operating parameters of the slave frequency converter meet the operating conditions for the slave brake mechanism; upon receiving the operation ready signal, simultaneously performing the following two operations: performing the control operation corresponding to the control command on the master brake mechanism; and sending an operation command to the slave frequency converter to enable the slave frequency converter to perform the control operation on the slave brake mechanism.

[0006] This application also provides a brake mechanism control method applied to a slave frequency converter. The brake mechanism control method includes: adjusting the slave operating parameters of the slave frequency converter according to the received operating control information; when the slave operating parameters meet the operating conditions for the slave brake mechanism, maintaining the state of the slave brake mechanism and sending an operation ready signal to the master frequency converter; and after receiving the operation command sent by the master frequency converter based on the operation ready signal, performing the control operation corresponding to the operation command on the slave brake mechanism.

[0007] This application also provides a brake mechanism control device, comprising: a first adjustment module, configured to adjust the host operating parameters of the host inverter according to the received control command; a first processing module, configured to maintain the state of the host brake mechanism and wait for an operation ready signal sent by the slave inverter when the host operating parameters meet the operating conditions for the host brake mechanism; wherein the operation ready signal indicates that the slave operating parameters of the slave inverter meet the operating conditions for the slave brake mechanism; and a first control module, configured to execute the control operation corresponding to the control command on the host brake mechanism and send an operation command to the slave inverter after receiving the operation ready signal, so that the slave inverter executes the control operation on the slave brake mechanism.

[0008] This application also provides an electronic device, including: a memory for storing a computer program; and a processor for executing the computer program to implement the steps of the brake mechanism control method described above.

[0009] This application solves the technical problem in existing master-slave control methods where the main inverter does not immediately execute control operations after its own operating parameters meet the operating conditions for the main brake mechanism. Instead, it maintains the state of the main brake mechanism until it receives the operation ready signal from the slave inverter, i.e., until the slave's operating parameters also meet the operating conditions for the slave brake mechanism. Only then does it execute control operations on the main brake mechanism and send operation commands to the slave inverter. This allows the slave inverter to execute the same control operation on the slave brake mechanism. The actions of both the main and slave brake mechanisms are triggered after the main inverter receives the operation ready signal from the slave inverter. This solves the technical problem that in existing master-slave control methods, the two brake mechanisms are independently triggered by their respective inverters, making it difficult to maintain consistent actions and leading to incoordination in the torque output or operating frequency of the two motors. This achieves the technical effect of coordinated action of the two brake mechanisms, improving equipment operating efficiency and safety. Attached Figure Description

[0010] To more clearly illustrate the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is a diagram illustrating a bidirectional communication structure between a master inverter and a slave inverter, provided in an embodiment of this application. Figure 2 This is a diagram illustrating another bidirectional communication structure between a master inverter and a slave inverter provided in an embodiment of this application. Figure 3 A flowchart illustrating the steps of a brake mechanism control method provided in this application embodiment; Figure 4 A timing diagram showing the entire process from start-up to shutdown of the dual-motor drive system provided in the embodiments of this application; Figure 5 This is a flowchart illustrating the steps of another brake mechanism control method provided in an embodiment of this application. Detailed Implementation

[0012] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0013] This application provides a brake mechanism control method applied to a master frequency converter. The master and slave frequency converters form a dual-motor drive system. The master frequency converter drives one motor, and the slave frequency converter drives the other motor. The two motors drive the same load together through transmission components such as reducers, couplings, steel cables, or chains. The master frequency converter controls one brake mechanism, referred to as the master brake mechanism in this embodiment, and the slave frequency converter controls another brake mechanism, referred to as the slave brake mechanism in this embodiment. The two brake mechanisms are structurally independent, each acting on the shaft of its respective motor or its respective transmission component.

[0014] In some embodiments, the lifting machinery is a grab bucket crane, and the driven load is the grab bucket of the grab bucket crane. Two motors drive the same grab bucket through their respective reducers and wire ropes. The outputs of the two motors must be coordinated for the grab bucket to complete its normal opening and closing action. In other embodiments, the driven load is the hoisting drum of a gantry crane, the lifting mechanism of a bucket wheel stacker-reclaimer, or the tilting mechanism of a converter. Two motors are rigidly connected through a gearbox and act together on the same output shaft.

[0015] A bidirectional communication connection is established between the master inverter and the slave inverter. For example... Figure 1 As shown, in some embodiments, the master inverter and the slave inverter each have a CAN (Controller Area Network) master-slave communication card. The CANH (CAN High) terminal of the master inverter's communication card is connected to the CANH terminal of the slave inverter's communication card, and the CANL (CAN Low) terminal is connected to the CANL terminal, forming a differential transmission CAN bus link. The CAN bus uses differential level transmission, and common-mode interference is canceled at the receiving end, making it suitable for environments with strong electromagnetic interference where the inverter operates. Simultaneously, the CAN protocol itself has bit arbitration and automatic retransmission mechanisms; if a single frame of data is corrupted, it can be automatically recovered by the link layer without upper-layer intervention. In some embodiments, the CAN bus communication rate is set to 500kbps. In other embodiments, it is set to 250kbps or 1Mbps depending on the wiring length; the longer the wiring length, the lower the communication rate.

[0016] like Figure 2As shown, each of the master and slave frequency inverters is equipped with a fiber optic master-slave communication card. The Tx (Transmit) port of the master inverter's communication card is connected to the Rx (Receive) port of the slave inverter's communication card via a fiber optic cable. The Rx port of the master inverter's communication card is connected to the Tx port of the slave inverter's communication card via another fiber optic cable, forming a full-duplex fiber optic link with Tx and Rx cross-connection. The fiber optic link is electrically completely isolated and is not affected by common-mode interference generated by the motor cable and braking unit, making it suitable for scenarios where the two inverters are installed far apart or where there is severe interference in the field. Furthermore, the bidirectional communication connection between the master and slave inverters is established via PROFINET, PROFIBUS-DP, or RS485. Any communication method that can establish bidirectional data exchange capability between the master and slave inverters can be used to carry the operation ready signal and operation command in this embodiment. This embodiment does not limit the specific form of the communication medium and communication protocol. In practical applications, the system can be configured with either one master inverter and one slave inverter, or one master inverter and two or more slave inverters.

[0017] Specifically, the data sent from the master inverter to the slave inverter is a fixed-length message, totaling eight bytes. The zeroth byte is the frame header, used for message start identification; the first byte is the slave address, used for addressing the target slave inverter when multiple slave inverters exist; the second byte is the control word, carrying various instructions bit by bit; the third and fourth bytes are the high and low octets of the frequency data, respectively; the fifth and sixth bytes are the high and low octets of the torque data, respectively; and the seventh byte is the CRC check byte, used by the receiving end to verify message integrity, as shown in Table 1.

[0018] Table 1. CAN message frame structure table sent from the master inverter to the slave inverter

[0019] In the control word, the zeroth bit is the running command bit, the first bit is the direction bit, the second bit is the fault reset bit, the third bit is the free stop bit, the fourth bit is the brake operation command bit, the fifth bit is the jog command bit, the sixth bit is the DC braking bit, and the seventh bit is the starting frequency start bit, as shown in Table 2.

[0020] Table 2 Control Word Structure Table

[0021] The data sent from the slave inverter to the master inverter is also an eight-byte message. The zeroth byte is the frame header; the first byte is the local address; the second byte is the fault code; the third and fourth bytes are the high and low octets of the status word, respectively; the fifth byte carries the operation ready information; the sixth byte is a reserved byte for future function expansion; and the seventh byte is the CRC (Cyclic Redundancy Check) byte, as shown in Table 3.

[0022] Table 3. CAN message frame structure table sent from slave inverter to master inverter

[0023] In this configuration, the high four bits of the fifth byte are used to carry one type of operation ready signal, and the low four bits are used to carry another type of operation ready signal. An operation ready signal can be represented entirely by a single binary bit or by multiple bits. In this embodiment, four binary bits are allocated to each type of operation ready signal so that the program can directly perform masking and shifting operations on a half-byte basis when retrieving values, saving the overhead of bit-by-bit judgment and improving the execution efficiency of communication tasks; or, the operation ready signal occupies only one binary bit, with the remaining bits reserved; or, the operation ready signal is not merged with the status word in the same frame, but is sent by the slave inverter in an independent event frame, and the master inverter immediately triggers corresponding processing upon receiving the event frame, thereby shortening the transmission delay of the ready information.

[0024] The master inverter and slave inverter each drive their respective brake mechanisms through their output channels. An internal relay output is provided in the inverter, with the relay contacts connected in series in the excitation circuit of the brake mechanism. When the relay is energized, the excitation coil of the brake mechanism is energized, and the brake opens; when the relay is released, the excitation coil is de-energized, and the brake closes under spring force. Alternatively, the inverter can use a solid-state relay or transistor output to drive an intermediate relay, which then drives the brake mechanism, to accommodate applications with high current in the brake mechanism's excitation circuit. Alternatively, the brake mechanism can be a hydraulic brake, with the inverter output signal controlling the solenoid directional valve of the hydraulic station, using hydraulic pressure to open and close the brake. The brake mechanism can be a disc brake, block brake, or band brake; this embodiment does not limit this.

[0025] The brake mechanism is equipped with limit switches or micro switches, whose contact signals are connected to the digital input terminals of the frequency converter. The frequency converter uses these signals to determine whether the mechanical action of the brake mechanism on this side is complete. If no corresponding completion signal is detected within a set time, the frequency converter determines that the brake mechanism on this side is malfunctioning and outputs fault information; alternatively, the frequency converter determines whether the brake mechanism is energized by detecting the presence or absence of current in the excitation circuit of the brake mechanism. The above feedback is used for monitoring the status of the brake mechanism on this side and for fault reporting.

[0026] Based on the above system structure, such as Figure 3 As shown, the brake mechanism control method provided in this embodiment includes: S101: Adjust the host operating parameters of the host frequency converter according to the received control instructions.

[0027] In this embodiment, the control command refers to an instruction requiring the main inverter to change its current operating status. In some embodiments, the control command is issued from the host control system to the main inverter via a fieldbus. In other embodiments, the control command is sent from buttons, handles, or the master controller on the control panel through the digital input terminals of the main inverter. In still other embodiments, the control command is directly given by the human-machine interface panel of the main inverter. Regardless of the channel from which the control command comes, after receiving the control command, the main inverter adjusts its output in the direction required by the control command, causing the main inverter's operating parameters to change from the current value to the target value.

[0028] Main unit operating parameters refer to parameters that characterize the current operating status of the main unit inverter. These parameters can be single parameters, where the inverter only needs to monitor one physical quantity to determine its current operating status; or a combination of two or more parameters, where the operating status is considered satisfactory only when all parameters are within their set ranges. Physical quantities that can serve as main unit operating parameters include, but are not limited to, the inverter's output current, output power, DC bus voltage, motor speed, and other parameters that characterize drive capability establishment or operating speed. Main unit operating parameters can be obtained by directly sampling from the inverter's current and voltage sensors and then standardizing the data; or they can be estimated from the inverter's internal motor model based on the sampled current and flux linkage; or they can be calculated based on feedback from an encoder installed on the motor shaft.

[0029] S102: When the host operating parameters meet the operating conditions for the host brake mechanism, maintain the state of the host brake mechanism and wait for the operation ready signal sent by the slave inverter; wherein, the operation ready signal indicates that the slave operating parameters of the slave inverter meet the operating conditions for the slave brake mechanism.

[0030] In this embodiment, the operating condition for the main unit's brake mechanism refers to the judgment condition that the main unit's operating parameters must meet to allow control operations to be performed on the main unit's brake mechanism. This operating condition can be a single-threshold comparison form, where the judgment condition is met when the main unit's operating parameters are higher or lower than a certain set value; or it can be an interval form, where the judgment condition is met when the main unit's operating parameters fall within a certain set interval; or it can be a multi-parameter logical AND form, where multiple main unit operating parameters must each meet their respective thresholds for the condition to be deemed valid. Furthermore, to avoid repeated fluctuations in the main unit's operating parameters around the thresholds causing the condition to be repeatedly met and not met, a hysteresis is set for the judgment of the operating condition, i.e., a certain difference is left between the threshold at which the condition is met and the threshold at which the condition is no longer met. In other embodiments, it is required that the main unit's operating parameters meet the thresholds for the condition to be deemed valid; the number of control cycles can be set according to the actual operating conditions, and this embodiment does not limit this.

[0031] When the operating parameters of the main unit meet the operating conditions for the main unit's brake mechanism, the main unit inverter does not immediately execute control operations on the brake mechanism. Instead, it maintains the state of the brake mechanism and waits for the operation readiness signal sent by the slave inverter. Maintaining the state of the brake mechanism means that the main unit inverter does not change the drive output of the brake mechanism during this period, keeping the brake mechanism in the state it was in at the moment the operating conditions were just met. This can be achieved by maintaining the relay output driving the brake mechanism in its original state, or by internally locking the brake control flag, preventing the brake control task from generating new output actions during the waiting period.

[0032] In this embodiment, the operation ready signal is sent by the slave inverter, indicating that the slave inverter's operating parameters meet the operating conditions for the slave brake mechanism. The slave operating parameters and the master operating parameters correspond to each other in physical meaning, and the operating conditions of the slave brake mechanism and the master brake mechanism correspond to each other in their judgment forms, but their specific threshold values ​​can be the same or different. In some embodiments, the specifications and load distribution of the two motors are completely identical, and the master and slave sides use the same threshold values. In other embodiments, the specifications or transmission ratios of the two motors differ, and the master and slave sides independently set their threshold values ​​according to their respective motor parameters.

[0033] The slave inverter replies to the master inverter with status messages at fixed intervals. The operation ready signal is sent as a flag bit in the status message periodically. The master inverter checks this flag bit each time it parses a message. This embodiment is simple to implement and has retransmission capability. Even if some messages are lost, they can still be recovered in the next cycle. Alternatively, the slave inverter only sends an operation ready signal once when the slave operating parameters change from not meeting the operating conditions to meeting the operating conditions. After receiving the signal, the master inverter sets the internal ready flag. This embodiment uses less communication bandwidth and has a faster response.

[0034] Since the main inverter maintains the state of its braking mechanism even when its own conditions are met, the timing of the main inverter's braking mechanism's action is no longer determined solely by the main inverter's own condition, but also by the condition of the slave inverter. Therefore, neither of the two braking mechanisms will act before the other has met its operating conditions, thus preventing the load from being borne solely by a single drive system at any given moment.

[0035] S103: After receiving the operation ready signal, execute the control operation corresponding to the control command on the master brake mechanism, and send the operation command to the slave frequency converter so that the slave frequency converter can execute the control operation on the slave brake mechanism.

[0036] After receiving the operation ready signal, the master inverter performs the following two operations: first, it executes the control operation corresponding to the control command on the master brake mechanism; second, it sends an operation command to the slave inverter so that the slave inverter executes the same control operation on the slave brake mechanism within the same time window. It can be understood that since the transmission time of the operation command depends on the message period of the communication link, and under the various communication methods mentioned above, this period is usually on the order of milliseconds, much shorter than the time required for the brake mechanism to be fully engaged from electrical signal triggering, the mechanical actions of the two brake mechanisms are actually within the same time window.

[0037] Therefore, the operation of the two brake mechanisms is triggered by the starter inverter receiving the operation readiness signal from the slave inverter. Both brake mechanisms can open or close within the same time window, thus maintaining coordination between the torque output and operating frequency of the two motors. In applications such as grab bucket cranes, problems such as incomplete gripping and material leakage are eliminated, improving the equipment's operating efficiency and safety.

[0038] Furthermore, in this embodiment, the coordination of the two brake mechanisms relies entirely on the existing bidirectional communication connection between the master and slave frequency converters. There is no need to add an external synchronization controller, a position feedback device to the brake mechanism, or lay additional hardware wiring between the two frequency converters. Therefore, when implementing this method on an existing dual-motor drive system, the hardware modifications are minimal, and the system's wiring complexity and the number of potential fault points do not increase due to the introduction of brake synchronization functionality.

[0039] It should be noted that the division between the master inverter and the slave inverter in this embodiment is a logical division, not a fixed hardware division. In some embodiments, the two inverters use identical hardware and software, and their respective roles as master and slave in the system are determined by parameter settings. In other embodiments, a slave inverter is pre-designated as a backup master inverter. When the original master inverter fails, the backup master inverter takes over the master role through parameter switching, and the original master inverter becomes a slave. The system continues to operate according to the method provided in this embodiment after the role switch.

[0040] In an exemplary embodiment, the control command is a running command, the control operation is a brake release operation, and the brake mechanism control method further includes: after receiving the running command, sending a start command to the slave inverter; adjusting the host operating parameters of the host inverter according to the received control command, including: adjusting the output frequency of the host inverter to a preset brake release frequency, and establishing the output torque of the host inverter at the preset brake release frequency; maintaining the state of the host brake mechanism, including: when the output frequency of the host inverter reaches the preset brake release frequency and the output torque of the host inverter reaches a preset brake release threshold, controlling the host brake mechanism to remain in a closed state.

[0041] In some embodiments, the master inverter and slave inverter each drive a three-phase asynchronous motor with a rated power of 55 kW. Both motors act on the same grab load through reducers and steel cables. Before the process begins, both motors are stopped, and both the master and slave brake mechanisms are closed, with the load held by the combined mechanical braking force of the two brake mechanisms. The operator issues a running command through the control panel, which is received by the master inverter. The running command includes start requirements and running direction requirements. Figure 4 As shown, Figure 4 This illustrates the timing relationship of the dual-motor drive system from start-up to shutdown in one embodiment of this application. Figure 4 The topmost curve represents the forward or reverse rotation command. When the command changes from invalid to valid, it signifies the start of the startup process.

[0042] After receiving the run command, the master inverter sends a start command to the slave inverter. The start command can be carried in a message from the master inverter to the slave inverter. The run command bit in the message control word indicates that the slave inverter is required to start, the direction bit indicates the required running direction, and the frequency data byte in the message carries the frequency setpoint given by the master inverter; alternatively, the start command can only carry start / stop and direction information, with the frequency setpoint sent separately in a subsequent message after startup is complete. Because the slave inverter's startup is initiated uniformly by the master inverter, both motors can synchronously establish their operating status, ensuring that the subsequent operating parameters on both sides reach the judgment threshold synchronously.

[0043] Furthermore, while sending the start command to the slave inverter, the master inverter also sends the local acceleration time parameters and the operating parameter settings for the release phase to the slave inverter via a message, so that the slave inverter can start up in a consistent manner with the master inverter without having to repeat the settings on its own.

[0044] The main inverter adjusts its operating parameters according to the received operating instructions, specifically including: adjusting the output frequency of the main inverter to a preset release frequency, and establishing the output torque of the main inverter at this preset release frequency. For example... Figure 4 As shown, the output frequency of the main inverter starts from zero and rises along an acceleration ramp. After reaching the release frequency, it stops rising and remains at that release frequency. At this time, the main brake mechanism is still closed, and the motor rotor is mechanically locked by the brake mechanism. The actual speed is close to zero, and the release frequency output by the main inverter does not correspond to the actual speed of the motor, but exists as the setpoint of the speed loop. There is a large deviation between the setpoint of the speed loop and the feedback value close to zero, and the speed regulator then outputs saturation. Its output is limited and used as the torque setpoint, driving the motor to build up torque in the stalled state. Figure 4 The curve marked as the host torque verification value reflects the process of the host inverter's output torque gradually increasing from zero and eventually reaching the judgment threshold. Figure 4 The upper limit of torque is also marked, indicating the maximum value of the speed regulator output after limiting.

[0045] The output torque can be established through speed loop saturation output, or by temporarily switching the main inverter to torque control mode during the brake release phase, directly outputting the set torque value, and then switching back to speed control mode after the torque is established. Of course, other methods can also be used besides these two, depending on the actual operating conditions; this embodiment does not limit the specific method used.

[0046] In this embodiment, the operating parameters of the main unit are deemed to meet the operating conditions for the main unit's brake mechanism only when both conditions are met simultaneously: the output frequency of the main unit inverter reaches the preset release frequency and the output torque of the main unit inverter reaches the preset release threshold. The preset release threshold can be, but is not limited to, 30% to 80% of the motor's rated torque; or, for applications with large load variations, the preset release threshold can be set according to different operating conditions, with different thresholds for no-load and full-load conditions; or, it can be issued in real-time by the upper-level control system based on the current operating stage.

[0047] Furthermore, the preset release thresholds for the master inverter and the slave inverter are set independently. In some embodiments, the two motors are of the same specification and have equal load distribution, and the same preset release threshold is used on both sides. In other embodiments, the load distribution of the two motors has an inherent deviation, and the preset release thresholds on both sides are adjusted according to the proportion of their respective actual loads.

[0048] When the output frequency of the main inverter reaches the preset release frequency and the output torque reaches the preset release threshold, the main inverter controls the main brake mechanism to remain closed. In other words, although the main inverter is fully capable of opening the main brake mechanism, it does not perform the opening action; the main brake mechanism remains closed until the main inverter receives an operation-ready signal from the slave inverter. Figure 4 As shown in the curve marked as the master motor's release and closing commands, this command does not immediately change after the torque verification is passed. Instead, it changes from the closing state to the release state at a certain moment later. This moment is when the master inverter receives the slave operation ready signal and completes the judgment.

[0049] The process on the slave inverter side corresponds to that on the master inverter side. For example... Figure 4 As shown by the curves marked as slave devices, the slave inverter also adjusts its output frequency to the release frequency and establishes output torque at that frequency. After the slave torque verification value reaches the judgment threshold on the slave side, the slave inverter sends a release ready signal. Figure 4 The time when the slave torque verification is passed and the brake release ready signal is sent is marked next to the slave torque curve.

[0050] Upon receiving the operation ready signal, the master inverter simultaneously releases the master brake mechanism and sends an operation command to the slave inverter. In some embodiments, the operation command is carried by the brake operation command bit in the message control word sent from the master to the slave, indicating a request for the slave inverter to open the slave brake mechanism. After parsing this bit, the slave inverter immediately drives its local relay to open the slave brake mechanism.

[0051] After each performs its brake release operation, the master and slave frequency inverters do not immediately change their output frequency. Instead, they continue to operate at their preset brake release frequency within their respective preset brake release delays. The brake mechanism requires a mechanical action process from receiving the release signal to complete brake release. If the frequency inverter accelerates before this process is complete, the motor will accelerate before the braking torque is fully released, causing a current surge. Figure 4 As shown, Figure 4 The time period T1 marked in the figure is the release time. During this time period, the frequency curve of the host remains at the release frequency level, and then continues to rise.

[0052] The preset brake release delay can range from 0.1 seconds to 1 second, and can be set to 0.3 seconds; or the preset brake release delay can be set separately according to the type of brake mechanism, for example, a shorter value for electromagnetic power failure brakes and a longer value for hydraulic brakes. The preset brake release delay of the master inverter and the slave inverter are set independently. When both sides use the same type of brake mechanism, they are set to the same value; when both sides use brake mechanisms with different action times, the setting is based on the longest actual action time of the brake mechanism.

[0053] After the preset brake release delay ends, the main inverter accelerates from the preset brake release frequency to the set frequency, and the slave inverter follows the output frequency of the main inverter, maintaining synchronous operation between the two motors. Figure 4 As shown, the frequency curves of the master and slave devices rise to the set frequency and remain thereafter after T1. Figure 4 The curve marked as the slave brake release and closing command shows that the moment it jumps from the closing state to the release state basically coincides with the jump moment of the corresponding curve on the master side, reflecting the consistency of the action triggering of the two brake mechanisms.

[0054] Because both the main inverter and the slave inverter have established their respective output torque at their respective release frequencies before the brakes are released, both motors are capable of bearing the load at the moment the brake mechanism opens. The load will not drop due to insufficient driving capacity on one side. Furthermore, since the opening actions of the two brake mechanisms are completed within the same time window, the force on the two motors is consistent at the moment of opening. There will be no situation where one motor is stressed first while the other motor is idle. As a result, the operating frequencies of the two motors are consistent, and the grab bucket can open and close smoothly during the startup phase.

[0055] In some embodiments, the master brake mechanism and the slave brake mechanism adopt the same type of brake mechanism, and the mechanical action time on both sides is basically the same; in other embodiments, the two sides adopt brake mechanisms with different action times due to structural layout requirements. In this case, an additional delay can be set on the side with faster action so that the actual completion time of the mechanical action on both sides tends to be consistent.

[0056] In one exemplary embodiment, after receiving the operation ready signal and before performing the following two operations, the brake mechanism control method further includes: acquiring the output frequency and output torque of the host inverter; and performing the following two operations, including: performing the following two operations when the output frequency reaches a preset release frequency and the output torque reaches a preset release threshold.

[0057] In this embodiment, there is a waiting period between the moment when the master inverter meets its own release condition and the moment it receives the operation ready signal from the slave inverter. The length of this waiting period depends on the time required for the slave inverter to build up output torque. During the waiting period, the output frequency and output torque of the master inverter may fluctuate. Factors such as grid voltage fluctuations, slight load movements, changes in the mechanical clearance of the brake mechanism, and motor parameter drift caused by temperature rise may all cause the output torque of the master inverter to fluctuate around the threshold, or even drop below the preset release threshold. If the master inverter immediately opens the master brake mechanism after receiving the operation ready signal based solely on the judgment at the start of the waiting period, it may release the brake when the actual driving capacity is insufficient, thus posing a risk of load drop.

[0058] Therefore, in this embodiment, after receiving the operation ready signal, the main inverter does not immediately perform the actions of releasing the brake and sending the operation command. Instead, it first re-acquires the current output frequency and output torque of the main inverter. In some embodiments, the main inverter directly reads the output frequency and output torque values ​​obtained from the latest sampling and calculation within the control cycle. In other embodiments, the main inverter continuously collects the output torque values ​​for several control cycles and takes the arithmetic average to suppress the influence of sampling noise on the judgment result. In still other embodiments, the main inverter simultaneously reads the instantaneous value and the filtered value, and only considers the condition to be met when both meet the threshold.

[0059] After obtaining the current output frequency and output torque, the main inverter compares them with the preset release frequency and preset release threshold, respectively. Only when the output frequency reaches the preset release frequency and the output torque reaches the preset release threshold will the main inverter perform the two actions of releasing the main brake mechanism and sending an operation command to the slave inverter. The threshold used for this comparison can be exactly the same as the threshold used at the start of the waiting period; or the torque threshold used for this comparison can be slightly lower than the torque threshold used at the start of the waiting period, with a hysteresis between the two, to avoid repeated invalid judgments due to normal small fluctuations in torque near the threshold.

[0060] If the obtained output frequency or output torque fails to meet the corresponding threshold, the main inverter will not perform the above two actions. The main inverter can continue to keep the main brake mechanism closed and continue to monitor the output frequency and output torque. Once both simultaneously meet the threshold again, the above two actions will be performed; or, if the conditions are not met, a new monitoring timer will be started. If the conditions are not met during this timer period, the start-up process will be determined to be unable to continue, the main inverter will stop and keep the main brake mechanism closed, and simultaneously send a stop command to the slave inverter; or, if the conditions are not met, the HMI will indicate that the current output torque is insufficient, allowing the operator to determine whether the load needs to be adjusted or the motor and transmission components need to be checked. Because the main inverter reconfirms its own output frequency and output torque before actually performing the brake release operation, any fluctuations in operating parameters that may occur during the waiting period are detected in time. The main inverter will not open the brake mechanism when the drive capability is insufficient, further reducing the risk of the load falling at the moment of brake release. Meanwhile, since this reconfirmation occurs before the operation command is sent to the slave inverter, if the confirmation result is not met, the slave inverter will not receive the operation command, and the slave brake mechanism will also remain closed. The brake mechanisms on both sides will remain consistent under abnormal conditions.

[0061] In an exemplary embodiment, the operation ready signal is a brake release operation ready signal; the brake mechanism control method further includes: when the output frequency of the main inverter reaches a preset brake release frequency and the output torque of the main inverter reaches a preset brake release threshold, starting a timer; when the timer duration reaches a first preset duration and no brake release operation ready signal is received, controlling the main brake mechanism to remain in a closed state, controlling the main inverter to stop, and sending a stop command to the slave inverter.

[0062] In this embodiment, the master inverter enters a waiting state after its own brake release condition is met. If the slave inverter is functioning normally, this waiting state will end immediately after the slave inverter completes torque build-up. However, if the slave inverter malfunctions, the slave-side motor or transmission components are abnormal, the communication link is interrupted, or the message continues to err, the master inverter will not receive the brake release operation ready signal, and the waiting state will continue. At this time, the master inverter is in a stalled state where the output frequency is maintained at the brake release frequency, the output torque is maintained at a high level, and the motor is locked by the brake mechanism. The motor windings and inverter power devices continue to heat up, and prolonged maintenance will cause device damage. Therefore, this embodiment sets an upper limit for the waiting state time.

[0063] In this embodiment, the operation ready signal is specifically a brake release operation ready signal. The brake release operation ready signal is carried by the high four bits of the fifth byte in the slave inverter's reply message. When these four bits are set to a predetermined non-zero value, it indicates that the slave inverter has completed torque build-up and is ready to release the brake; or the brake release operation ready signal is carried by a dedicated bit in the slave inverter's status word; or the brake release operation ready signal is sent together with the current measured output torque value of the slave inverter, so that the master inverter can know the actual torque level on the slave side at the same time as receiving the ready flag.

[0064] Timing begins when the main inverter's output frequency reaches the preset release frequency and the output torque reaches the preset release threshold. Timing starts after these conditions are met because the main inverter has not yet completed its preparation work. Even if the slave inverter is ready first, the main inverter cannot act immediately. When the main inverter's output frequency reaches the preset release frequency and the output torque reaches the preset release threshold, the main inverter is already in a waiting state. The length of the waiting time reflects the response of the slave inverter.

[0065] The timing operation can be implemented through a software counter inside the host inverter, which accumulates during the control cycle interruption and compares the accumulated value with the number of cycles corresponding to the first preset duration; or through a hardware timer inside the host inverter chip, which generates a timeout interrupt when the timer overflows; or by monitoring the message receiving interval of the communication link at the same time. If no message is received from the slave inverter for several consecutive cycles during the timing period, it can be directly determined as a communication interruption without waiting for the timing to end.

[0066] The first preset duration needs to cover the maximum time required for the slave inverter to build up torque under normal operating conditions, while not being too long so that the motor stalling and overheating exceed the allowable range. Its value range can be from 1 second to 10 seconds, and a specific value of 3 seconds is acceptable; or it can be dynamically issued by the upper control system based on the current load conditions, taking a larger value under heavy load conditions and a smaller value under light load conditions.

[0067] When the timing reaches the first preset duration and the main inverter has not yet received the brake release operation ready signal, the main inverter performs the following actions: first, it controls the main brake mechanism to remain closed; second, it controls the main inverter to stop; and third, it sends a stop command to the slave inverter.

[0068] It is understandable that a timeout means the status of the slave inverter is unclear. If the master inverter opens the master brake mechanism alone at this time, the load will be entirely borne by the master motor, while it is impossible to determine whether the slave motor has the capacity to output power. If the slave motor is actually in a faulty state, the load is very likely to go out of control. Therefore, in this embodiment, if a timeout occurs during the brake release phase, the master inverter does not open the master brake mechanism but keeps it in the closed state.

[0069] In some embodiments, the main inverter can directly block the output, and the motor stops under the braking force of the holding brake mechanism. In other embodiments, the main inverter first ramps down the output frequency to zero before blocking the output to avoid the current surge caused by direct blocking. The choice can be made according to the actual operating conditions; this embodiment does not specifically limit how to control the shutdown of the main inverter.

[0070] In some embodiments, the shutdown command is carried by the free stop position in the message control word sent from the master to the slave. In other embodiments, the shutdown command is implemented by resetting the run command bit in the control word; in still other embodiments, the master inverter sends a dedicated fault shutdown message, which also carries a fault cause code, facilitating fault location by the slave inverter and the upper control system. Even if the slave inverter itself does not detect any abnormality and is still in a torque-building waiting state, it can still shut down upon receiving the shutdown command from the master inverter, avoiding prolonged stalling and overheating of the slave-side motor.

[0071] While performing the above actions, the main inverter can display fault information through the human-machine interface, prompting the operator to check the operating status of the slave inverter and the master-slave communication link; or trigger an external alarm device through a digital output; or report the current alarm status and fault code through the communication interface with the upper control system.

[0072] Because the main inverter explicitly maintains the main brake mechanism in the closed state and stops both machines after the waiting timeout, there will be no situation where only one side of the brake mechanism is open in the event of communication interruption or slave inverter failure. The load is always maintained by both sets of brake mechanisms, thus avoiding accidents such as abnormal opening of the grab bucket and loosening of the wire rope. At the same time, because the main inverter actively sends a stop command to the slave inverter, the stall state of both motors is promptly released, thereby reducing the risk of overheating of the motors and inverters.

[0073] In an exemplary embodiment, the control command is a shutdown command, and the control operation is a closing operation; adjusting the host operating parameters of the host inverter according to the received control command includes: reducing the output frequency of the host inverter and sending the output frequency setpoint to the slave inverter in real time during the reduction process, so that the slave inverter operates with the output frequency setpoint as the speed command; maintaining the state of the host brake mechanism includes: maintaining the preset closing frequency operation when the output frequency of the host inverter decreases to the preset closing frequency, and controlling the host brake mechanism to remain in the open state.

[0074] This embodiment describes the process of the system transitioning from a running state to a stopped state. Before this process begins, both motors are in a running state, and both the master brake mechanism and the slave brake mechanism are in an open state. The load is entirely borne by the electromagnetic torque of the two motors.

[0075] The operator issues a stop command through the control panel, and the main inverter receives the stop command. For example... Figure 4 As shown, Figure 4 When the uppermost running command curve changes from valid to invalid, it marks the start of the shutdown process. After that, the output frequency of the main inverter begins to decrease from the set frequency along the deceleration ramp.

[0076] The master inverter adjusts the master operating parameters according to the shutdown command, specifically including: reducing the output frequency of the master inverter and sending the output frequency setpoint to the slave inverter in real time during the reduction process, so that the slave inverter runs with the output frequency setpoint as the speed command.

[0077] The main inverter can reduce the output frequency according to a linear deceleration curve, with the deceleration time ranging from 2 to 10 seconds (5 seconds is a specific value); or it can decelerate according to an S-curve, reducing the frequency change rate at the beginning and end of the deceleration to reduce the impact on the transmission components; or it can use segmented deceleration, using a larger frequency change rate in the high-frequency range to shorten the downtime, and switching to a smaller frequency change rate when approaching the closing frequency to ensure precise alignment of the frequencies on both sides.

[0078] The transmission period can range from 1 millisecond to 10 milliseconds (specifically 2 milliseconds). The shorter the transmission period, the closer the frequency trajectory followed by the slave inverter is to the actual trajectory on the master side. Alternatively, the slave inverter can perform linear interpolation of the frequency setpoint between two receptions, thus achieving a smooth frequency setpoint even with a longer transmission period. The following accuracy is controlled within ±0.1Hz; or adjusted according to the flexibility of the transmission components. When using flexible connections such as steel wire cables, the accuracy can be relaxed to ±0.2Hz, while when using rigid connections such as gearboxes, it can be tightened to ±0.05Hz.

[0079] The slave inverter operates using the received output frequency setpoint as the speed command. In some embodiments, the slave inverter directly feeds this setpoint to the speed loop setpoint of its own unit. In other embodiments, the slave inverter adds a compensation amount to the setpoint to eliminate inherent deviations between the two sides before feeding it into the speed loop. Since the output frequencies of both inverters are always provided by the same source, the two motors maintain the same speed throughout the deceleration process, and the load does not experience additional force due to the speed difference between the two sides.

[0080] When the output frequency of the main inverter drops to the preset closing frequency, the main inverter maintains the operation at the preset closing frequency and controls the main brake mechanism to remain open.

[0081] like Figure 4 As shown, the frequency curve of the main unit stops decreasing after dropping to the level marked as the closing frequency, and instead remains there for a period of time. The time period T2 is marked above this segment in the figure. Within this segment, the main unit's release and closing command curves remain in the release state until a certain moment after the start of this segment, when it jumps to the closing state. This moment is precisely when the main unit inverter receives the closing ready signal sent by the slave unit inverter.

[0082] In some embodiments, the preset closing frequency ranges from 0.5Hz to 3Hz, specifically from 1Hz to 2Hz. In other embodiments, the preset closing frequency is set as a percentage of the motor's rated frequency, ranging from 1% to 5% of the rated frequency. In still other embodiments, the preset closing frequency is set in stages according to the load inertia, with lower values ​​used for loads with greater inertia to adequately reduce speed.

[0083] Considering that at the moment of closing, the brake mechanism is still in the open state, the motor is rotating normally, and the load is borne by the electromagnetic torque, the torque level is the result of the operating conditions, rather than a condition that needs to be established. Therefore, in this stage, only the output frequency of the main inverter is used as the basis for judgment, and the output torque is no longer judged.

[0084] When the output frequency of the main inverter drops to the preset closing frequency, although the main inverter is ready to perform the closing operation, it does not immediately close the main brake mechanism. Instead, it keeps the main brake mechanism open and maintains operation at the preset closing frequency, waiting for the operation ready signal from the slave inverter. The process on the slave inverter side is the same; its frequency curve also drops to the closing frequency and maintains operation, while sending a closing ready signal to the main inverter at this time.

[0085] Upon receiving the operation ready signal, the master inverter simultaneously closes the master brake mechanism and sends an operation command to the slave inverter. Upon receiving the operation command, the slave inverter closes the slave brake mechanism.

[0086] Because the speed of both motors has been reduced to the same low safety range before the two sets of brake mechanisms close, the sliding friction work at the moment of brake mechanism closure is small. Furthermore, since the closing action of the two sets of brake mechanisms is completed in the same time window, there will be no situation where one side is already braking while the other side is still dragging. There will be no torque impact or current impact between the two motors due to inconsistent braking states, preventing closing impact. The steel wire rope of the grab bucket will not have the phenomenon of one side being taut and the other side being slack, making the stopping process smoother.

[0087] In an exemplary embodiment, the operation ready signal is a closing operation ready signal; the brake mechanism control method further includes: when the output frequency of the master inverter decreases to a preset closing frequency, starting a timer; when the timer duration reaches a second preset duration and no closing operation ready signal is received, performing a closing operation on the master brake mechanism and sending a closing command to the slave inverter.

[0088] In this embodiment, the master inverter enters a waiting state after its own frequency drops to the preset closing frequency. If the slave inverter is functioning normally, this waiting state will end immediately after the slave inverter's frequency also drops to the closing frequency. If the slave inverter malfunctions or the communication link is interrupted, both the master and slave inverters will handle the fault according to the fault mechanism, and both will immediately stop and close the brake mechanism to prevent the load from falling. In this embodiment, the operation ready signal is specifically the closing operation ready signal. The closing operation ready signal can be carried by the lower four bits of the fifth byte in the slave inverter's reply message, or it can share a different segment of the same byte with the release operation ready signal. The master inverter determines which segment to read based on the current operating stage.

[0089] When the output frequency of the master inverter decreases to the preset closing frequency, timing begins. Since the master inverter's output frequency decreasing to the preset closing frequency indicates that it has completed all its preparations, the length of the waiting time reflects the response of the slave inverter. The value of the second preset duration needs to cover the time deviation required for the slave inverter to complete deceleration under normal operating conditions, while also being short enough to prevent the load from being suspended solely by electromagnetic torque for an extended period. Since both inverters share the same frequency source during deceleration, they normally reach the closing frequency very close together, so the second preset duration can be shorter than the first preset duration. In some embodiments, the value of the second preset duration ranges from 0.5 seconds to 5 seconds, specifically 2 seconds. The timing durations of the master and slave inverters can be the same or different. Similarly, the timing durations used by the same inverter during the release and closing phases can also be the same or different, set according to the actual operating conditions.

[0090] If the timing reaches the second preset duration and the main inverter has not yet received the closing operation ready signal, the main inverter performs the following actions: It performs a closing operation on the main brake mechanism, i.e., actively closes the main brake mechanism, allowing the load on the main side to be borne by mechanical braking force instead of electromagnetic torque; and sends a closing command to the slave inverter. This closing command can be carried using the same message bits as the operation command in the normal process; or it can be sent using a dedicated message frame carrying a flag indicating forced closing. Upon receiving this message, the slave inverter unconditionally closes its brake mechanism without further judgment of its own conditions; or the main inverter can repeatedly send the closing command multiple times to increase the probability of command delivery even when communication quality deteriorates.

[0091] Furthermore, while performing the above actions, the main inverter displays fault information through the human-machine interface, prompting the operator to check the status of the slave inverter and the master-slave communication link; or the main inverter reports an alarm status to the upper control system through the communication interface. Because the main inverter actively closes its own brake mechanism and sends a closing command to the slave inverter after the waiting timeout, even if the slave inverter fails to provide ready information according to the normal procedure, the load can be held up by mechanical braking force again in a short time, and will not be in a state of suspension by electromagnetic torque alone for a long time.

[0092] In an exemplary embodiment, after performing a closing operation on the main brake mechanism, the brake mechanism control method further includes: maintaining a preset closing frequency during a preset closing delay, so that the main inverter continuously outputs torque before the main brake mechanism is fully closed, and blocking the output after the preset closing delay ends.

[0093] The braking mechanism undergoes a mechanical process from receiving a closing signal to fully closing and generating the rated braking torque. This process includes the attenuation of the excitation coil current, the release of the armature, the compression of the spring, and the displacement of the brake arm and the contact of the bushing; each step requires time. During this period, although the braking mechanism has begun to operate, it cannot provide sufficient braking torque to support the load. If the inverter blocks the output at the same time as issuing the closing signal, the load will not receive either electromagnetic torque support or sufficient mechanical braking torque support during the period before the braking mechanism fully closes, and will slide downwards under the action of gravity, resulting in hook slippage.

[0094] Therefore, in this embodiment, after the main inverter performs a closing operation on the main brake mechanism, it does not immediately block the output, but continues to maintain the preset closing frequency within a preset closing delay. For example... Figure 4 As shown, Figure 4 The time period T2 marked in the figure is the closing time. During this time period, the frequency curve of the main unit remains at the closing frequency level, and then continues to drop to zero.

[0095] During this period, the main inverter maintains its speed loop in operation, continuously outputting torque at the preset closing frequency. As the braking mechanism gradually generates braking torque, the required output torque of the motor gradually decreases, and the combined effect keeps the load under control.

[0096] The preset closing delay ranges from 0.1 seconds to 1 second, specifically 0.3 seconds; or it can be set to 1.2 to 1.5 times the rated closing action time of the brake mechanism; or it can be set separately according to the type of brake mechanism, for example, a shorter value for electromagnetic power failure brakes and a longer value for hydraulic brakes due to the lag in the response of the hydraulic circuit. The preset closing delays of the master inverter and the slave inverter are set independently. When both sides use the same type of brake mechanism, they are set to the same value. When both sides use brake mechanisms with different action times, they are set according to the actual action time of their respective brake mechanisms.

[0097] After the preset closing delay ends, the main inverter blocks the output. In some embodiments, the main inverter directly blocks the drive pulses of the inverter bridge, and the motor is kept stationary by the braking torque of the brake mechanism. In other embodiments, the main inverter first reduces the output frequency from the preset closing frequency to zero at a large rate of change before blocking the output, so that the output current decays smoothly. In still other embodiments, the main inverter maintains the brake mechanism closed for a period of time after blocking the output, and only ends the shutdown process after confirming that the feedback signal of the brake mechanism is valid.

[0098] Furthermore, the main inverter monitors the output torque of the machine during the preset closing delay period. If the output torque decreases significantly over time, it indicates that the brake mechanism is building up braking torque normally. The output can be blocked after the delay ends. If the output torque does not decrease throughout the entire delay period, it indicates that the brake mechanism may have a malfunction in closing. The main inverter extends the holding time and outputs an alarm to prompt the operator to check the brake mechanism.

[0099] Because the main inverter continuously outputs torque before the brake mechanism is fully closed, the load is always supported during the establishment of braking torque, preventing slippage during the closing of the brake mechanism. Furthermore, since this maintenance process is connected to the execution time of the closing operation, and the closing operation is initiated simultaneously on both sides, the output state of the two motors is consistent during the maintenance period, and there will be no situation where one side is still outputting while the other side has already blocked the output, thus keeping the load under balanced force.

[0100] Reference Figure 5 This application also provides a brake mechanism control method, applied to a slave frequency converter, the brake mechanism control method including: S201: Adjust the slave operating parameters of the slave frequency converter according to the received operation control information; S202: When the slave operating parameters meet the operating conditions for the slave brake mechanism, maintain the state of the slave brake mechanism and send an operation ready signal to the master inverter; S203: After receiving the operation command sent by the host inverter based on the operation ready signal, execute the control operation corresponding to the operation command on the slave brake mechanism.

[0101] In this embodiment, the slave inverter adjusts its slave operating parameters according to the received operating control information. The operating control information refers to the information sent by the master inverter to the slave inverter via a bidirectional communication connection, instructing the slave inverter to change its own operating status.

[0102] In some embodiments, the operation control information is a start command sent by the master inverter to the slave inverter after receiving an operation command. Upon receiving this start command, the slave inverter starts operation, adjusts its output frequency to a preset release frequency, and establishes output torque at that frequency. In this case, the slave inverter's operating parameters are its output frequency and output torque. In other embodiments, the operation control information is an output frequency setpoint sent by the master inverter to the slave inverter in real time during deceleration. The slave inverter uses this setpoint as its speed command, causing its own output frequency to decrease in tandem with the master inverter's output frequency. In this case, the slave inverter's operating parameters are its output frequency. In still other embodiments, the operation control information simultaneously includes start / stop information, direction information, frequency setpoint, and parameter settings. The slave inverter updates its own operating status and settings parameters according to different fields.

[0103] When the slave operating parameters meet the operating conditions for the slave brake mechanism, the slave inverter maintains the state of the slave brake mechanism and sends an operation ready signal to the master inverter. In this case, the control operation is a brake release operation. Meeting the operating conditions means that the slave inverter's output frequency reaches a preset brake release frequency and its output torque reaches a preset brake release threshold. The slave inverter then keeps the slave brake mechanism in the closed state and sends a brake release operation ready signal to the master inverter. In other embodiments, the control operation is a closing operation. Meeting the operating conditions means that the slave inverter's output frequency decreases to a preset closing frequency. The slave inverter then maintains this closing frequency, keeps the slave brake mechanism in the open state, and sends a closing operation ready signal to the master inverter.

[0104] Among them, the preset release threshold of the slave inverter is the same as the preset release threshold of the master inverter, or the two are set separately according to the rated torque of their respective motors and the actual load ratio.

[0105] In some embodiments, the preset closing frequency of the slave inverter is the same as the preset closing frequency of the master inverter to ensure that the two sides are aligned at the same frequency level; in other embodiments, considering the difference in transmission ratio on both sides, the two are taken with slightly different values ​​so that the load linear speeds of the two motors are the same when they meet their respective conditions.

[0106] After receiving an operation command from the master inverter based on the operation ready signal, the slave inverter executes the control operation corresponding to the operation command on the slave brake mechanism. In some embodiments, the operation command is carried by a dedicated bit in the message control word sent from the master to the slave. Setting this bit indicates that the slave inverter is required to open the slave brake mechanism, and resetting this bit indicates that the slave inverter is required to close the slave brake mechanism. In other embodiments, the operation command is carried by an independent byte in the message, and different values ​​of the byte correspond to different control operations, facilitating the subsequent expansion of more brake action types.

[0107] After parsing the operation command, the slave inverter immediately drives its local output channel to execute the corresponding action on the slave brake mechanism. Before executing the action, the slave inverter can perform a consistency check between the operation command and the current operating stage. If they do not match, the operation will not be executed and an alarm will be output to prevent erroneous actions caused by bit errors. Alternatively, it can require two consecutive frames of messages to give the same command before execution to improve anti-interference capability.

[0108] Since the slave inverter does not operate automatically when its own conditions are met, the action of the slave brake mechanism is entirely determined by the master inverter, allowing both brake mechanisms to be triggered from the same source. Furthermore, because the slave inverter proactively reports its own readiness status before operating, the master inverter can make a decision based on information from both sides. Neither brake mechanism will operate before the other side is ready, and the load is consistently maintained by both motors or both brake mechanisms with sufficient load-bearing capacity throughout the entire process.

[0109] In an exemplary embodiment, the operation ready signal is either a brake release operation ready signal or a brake closing operation ready signal; the brake mechanism control method further includes: starting a timer when sending an operation ready signal to the master inverter; when the operation ready signal is a brake release operation ready signal, controlling the slave brake mechanism to remain in a closed state, controlling the slave inverter to stop, and sending a stop command to the master inverter when the timer duration reaches a third preset duration and no operation command is received when the timer duration reaches a fourth preset duration and no operation command is received when the operation ready signal is a brake closing operation ready signal; and performing a brake closing operation on the slave brake mechanism when the timer duration reaches a fourth preset duration and no operation command is received when the operation ready signal is a brake closing operation ready signal.

[0110] In this embodiment, the slave inverter enters a waiting state after sending an operation ready signal. If the master inverter and communication link are normal, this waiting state will end immediately after the master inverter completes its own condition judgment and issues an operation command. However, if the master inverter malfunctions, the master-side motor or transmission components are abnormal, or communication from the slave inverter to the master inverter is interrupted while communication in the opposite direction remains open, the slave inverter will not be able to receive the operation command. In this case, the slave inverter also needs to have independent protection capabilities.

[0111] When the slave inverter sends an operation ready signal to the master inverter, it begins timing. At this point, the slave inverter is already in a waiting state. It's important to note that the timing start point of the slave inverter and the master inverter are physically different. The moment when the master inverter's own conditions are met and the moment the slave inverter sends its ready signal usually do not coincide; they time independently and do not affect each other. The slave inverter's timing can be implemented using a software counter or a hardware timer; alternatively, the slave inverter can monitor the message reception interval from the master inverter while timing. When the reception interval continuously exceeds a set value, communication interruption can be determined without waiting for the timing to end.

[0112] When the operation ready signal is the brake release ready signal, if the timer reaches the third preset duration and the slave inverter still has not received the operation command, the slave inverter controls the slave brake mechanism to remain closed, stops the slave inverter, and sends a stop command to the master inverter. It can be understood that a timeout means the status on the master inverter side is unclear. If the slave inverter opens the slave brake mechanism at this time, the entire load will be on the slave motor. If the master inverter is actually in a faulty state, the load may become uncontrollable. Therefore, the slave inverter needs to control the brake mechanism to close under abnormal conditions.

[0113] Controlling the slave inverter to stop is to relieve the stalled state of the slave-side motor. In some embodiments, the slave inverter can directly block the output, or first reduce the output frequency to zero before blocking the output. Simultaneously, a stop command is sent to the master inverter, allowing the master inverter to stop as well without detecting the abnormality, thus preventing prolonged stalling of the master-side motor. This stop command can be carried in the fault code byte of the slave reply message, or by the slave inverter sending a dedicated fault message frame, which also carries the cause code for the timeout fault. The third preset duration ranges from 1 to 10 seconds (specifically 3 seconds), and can be the same as or slightly greater than the first preset duration of the master inverter. This ensures that the protection action on the master inverter side takes precedence over the slave inverter side, with the master inverter leading the abnormality handling; the slave inverter only acts independently if the master inverter fails to respond, thereby avoiding conflicts caused by simultaneous processing on both sides.

[0114] When the operation ready signal is a closing operation ready signal, if the timing duration reaches the fourth preset duration and the slave inverter still has not received the operation command, the slave inverter will perform a closing operation on the slave brake mechanism. If a timeout occurs during the closing phase, the slave brake mechanism is in the open state, and the load on the slave side is entirely supported by electromagnetic torque. If waiting continues, and the slave inverter blocks its output for any reason, the load will lose support. Therefore, the slave inverter no longer waits for the master inverter's command but actively closes the slave brake mechanism, allowing the load to be borne by mechanical braking force. The fourth preset duration ranges from 0.5 seconds to 5 seconds, specifically 2 seconds, or the same as or slightly greater than the master inverter's second preset duration, to ensure that the master inverter's forced closing command is delivered first. The slave inverter will only automatically force close the circuit if the command is indeed not delivered.

[0115] Furthermore, after the slave inverter performs forced closing, it continues to maintain the preset closing frequency for a preset closing delay until the slave brake mechanism is fully closed before blocking the output, so as to avoid the load drop during the closing process of the brake mechanism; or while performing forced closing, the slave inverter displays fault information through the human-machine interface of the machine and reports the alarm status to the upper control system through the communication interface.

[0116] Because the slave inverter is equipped with fault and communication timeout protection mechanisms in two stages, the slave inverter can independently keep its side in a safe state regardless of whether the abnormality occurs in the startup or shutdown stage, or whether the abnormality occurs on the master inverter side or on the communication link. With the timeout protection on the master inverter side, in the event of a fault or communication interruption on either side of the system, both sets of braking mechanisms will eventually be in a closed state, and the load will always be maintained by mechanical braking force.

[0117] This application embodiment also provides a brake mechanism control device, including: a first adjustment module, used to adjust the host operating parameters of the host inverter according to the received control command; a first processing module, used to maintain the state of the host brake mechanism when the host operating parameters meet the operating conditions for the host brake mechanism, and wait for the operation ready signal sent by the slave inverter; wherein, the operation ready signal indicates that the slave operating parameters of the slave inverter meet the operating conditions for the slave brake mechanism; and a first control module, used to execute the control operation corresponding to the control command on the host brake mechanism after receiving the operation ready signal, and to send the operation command to the slave inverter so that the slave inverter executes the control operation on the slave brake mechanism.

[0118] In an exemplary embodiment, the control command is a run command, and the control operation is a brake release operation. The first processing module is specifically used to send a start command to the slave inverter after receiving the run command, and to adjust the output frequency of the master inverter to a preset brake release frequency, and to establish the output torque of the master inverter at the preset brake release frequency; to maintain the state of the master brake mechanism, including: when the output frequency of the master inverter reaches the preset brake release frequency and the output torque of the master inverter reaches the preset brake release threshold, controlling the master brake mechanism to remain in a closed state.

[0119] In an exemplary embodiment, the operation ready signal is a brake release operation ready signal; the brake mechanism control device further includes: a first timing module, used to start timing when the output frequency of the main inverter reaches a preset brake release frequency and the output torque of the main inverter reaches a preset brake release threshold; the first control module is also used to control the main brake mechanism to remain in a closed state, control the main inverter to stop, and send a stop command to the slave inverter when the timing duration reaches a first preset duration and no brake release operation ready signal is received.

[0120] In an exemplary embodiment, the control command is a shutdown command, and the control operation is a closing operation; adjusting the host operating parameters of the host inverter according to the received control command includes: reducing the output frequency of the host inverter and sending the output frequency setpoint to the slave inverter in real time during the reduction process, so that the slave inverter operates with the output frequency setpoint as the speed command; maintaining the state of the host brake mechanism includes: maintaining the preset closing frequency operation when the output frequency of the host inverter decreases to the preset closing frequency, and controlling the host brake mechanism to remain in the open state.

[0121] In an exemplary embodiment, the operation ready signal is a closing operation ready signal; the first timing module is further configured to start timing when the output frequency of the master inverter decreases to a preset closing frequency; the first control module is further configured to perform a closing operation on the master brake mechanism and send a closing command to the slave inverter when the timing duration reaches a second preset duration and no closing operation ready signal is received.

[0122] In an exemplary embodiment, the first control module is further configured to maintain the operation of the preset closing frequency within the preset closing delay, so that the main inverter continuously outputs torque before the main brake mechanism is fully closed, and blocks the output after the preset closing delay ends.

[0123] This application embodiment also provides another brake mechanism control device, including: a second adjustment module, used to adjust the slave operating parameters of the slave inverter according to the received operation control information; a second processing module, used to maintain the state of the slave brake mechanism and send an operation ready signal to the master inverter when the slave operating parameters meet the operating conditions for the slave brake mechanism; and a second control module, used to execute the control operation corresponding to the operation command on the slave brake mechanism after receiving the operation command sent by the master inverter based on the operation ready signal.

[0124] In an exemplary embodiment, the operation ready signal is either a brake release operation ready signal or a brake closing operation ready signal; the brake mechanism control device further includes: a second timing module, configured to start timing when an operation ready signal is sent to the master inverter; the second control module is further configured to, when the operation ready signal is a brake release operation ready signal, control the slave brake mechanism to remain in a closed state, control the slave inverter to stop, and send a stop command to the master inverter when the timing duration reaches a third preset duration and no operation command is received; and when the operation ready signal is a brake closing operation ready signal, execute a brake closing operation on the slave brake mechanism when the timing duration reaches a fourth preset duration and no operation command is received.

[0125] This application also provides an electronic device, including: a memory for storing a computer program; and a processor for executing the computer program to implement the steps of the brake mechanism control method described in any of the above embodiments.

[0126] Embodiments of this application also provide a computer-readable storage medium storing a computer program, wherein the computer program is configured to execute the steps in any of the above embodiments of the brake mechanism control method when it is run.

[0127] In one exemplary embodiment, the aforementioned computer-readable storage medium may include, but is not limited to, various media capable of storing computer programs, such as a USB flash drive, read-only memory (ROM), random access memory (RAM), portable hard disk, magnetic disk, or optical disk.

[0128] The embodiments of this application also provide a computer program product, which includes a computer program that, when executed by a processor, implements the steps in any of the above embodiments of the brake mechanism control method.

[0129] Embodiments of this application also provide another computer program product, including a non-volatile computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps in any of the above embodiments of the brake mechanism control method.

[0130] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0131] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for controlling a brake mechanism, characterized in that, The brake mechanism control method, applied to a main inverter, includes: Adjust the host operating parameters of the host frequency inverter according to the received control commands; When the host operating parameters meet the operating conditions for the host brake mechanism, the host brake mechanism is maintained in its current state, and the system waits for the operation ready signal sent by the slave inverter; wherein, the operation ready signal indicates that the slave operating parameters of the slave inverter meet the operating conditions for the slave brake mechanism. Upon receiving the operation ready signal, the system executes the control operation corresponding to the control command on the master brake mechanism and sends an operation command to the slave inverter so that the slave inverter executes the control operation on the slave brake mechanism.

2. The brake mechanism control method according to claim 1, characterized in that, The control command is a running command, the control operation is a brake release operation, and the brake mechanism control method further includes: Upon receiving the operation command, a start command is sent to the slave inverter; The step of adjusting the host operating parameters of the host frequency inverter according to the received control instructions includes: The output frequency of the main inverter is adjusted to a preset release frequency, and the output torque of the main inverter is established at the preset release frequency. Maintaining the state of the main brake mechanism includes: When the output frequency of the main inverter reaches the preset release frequency and the output torque of the main inverter reaches the preset release threshold, the main brake mechanism is controlled to remain in a closed state.

3. The brake mechanism control method according to claim 2, characterized in that, The operation ready signal is the brake release operation ready signal; The brake mechanism control method further includes: When the output frequency of the main inverter reaches the preset release frequency and the output torque of the main inverter reaches the preset release threshold, the timing is started. When the timing reaches the first preset duration and the brake release operation ready signal is not received, the main brake mechanism is controlled to remain closed, the main inverter is controlled to stop, and a stop command is sent to the slave inverter.

4. The brake mechanism control method according to claim 1, characterized in that, The control command is a shutdown command, and the control operation is a closing operation; The step of adjusting the host operating parameters of the host frequency inverter according to the received control instructions includes: The output frequency of the master inverter is reduced, and during the reduction process, the output frequency setpoint is sent to the slave inverter in real time so that the slave inverter runs with the output frequency setpoint as the speed command; Maintaining the state of the main brake mechanism includes: When the output frequency of the main inverter drops to the preset closing frequency, the preset closing frequency is maintained and the main brake mechanism is controlled to remain open.

5. The brake mechanism control method according to claim 4, characterized in that, The operation ready signal is the closing operation ready signal; The brake mechanism control method further includes: When the output frequency of the main inverter drops to the preset closing frequency, the timing is started. When the timing reaches the second preset duration and the closing operation ready signal is not received, the closing operation is performed on the master brake mechanism, and a closing command is sent to the slave frequency converter.

6. The brake mechanism control method according to claim 4, characterized in that, After the closing operation is performed on the main brake mechanism, the brake mechanism control method further includes: The preset closing frequency is maintained within the preset closing delay so that the main inverter continuously outputs torque before the main brake mechanism is fully closed, and the output is blocked after the preset closing delay ends.

7. A method for controlling a brake mechanism, characterized in that, The brake mechanism control method, applied to slave frequency converters, includes: Adjust the slave operating parameters of the slave frequency converter according to the received operation control information; When the slave operating parameters meet the operating conditions for the slave brake mechanism, the state of the slave brake mechanism is maintained, and an operation ready signal is sent to the master inverter. After receiving the operation command sent by the host inverter based on the operation ready signal, the slave brake mechanism performs the control operation corresponding to the operation command.

8. The brake mechanism control method according to claim 7, characterized in that, The operation ready signal is either a release operation ready signal or a closing operation ready signal; The brake mechanism control method further includes: When the operation ready signal is sent to the host frequency inverter, the timing is started; When the operation ready signal is the brake release operation ready signal, if the timing duration reaches the third preset duration and no operation command is received, the slave brake mechanism is controlled to remain closed, the slave inverter is controlled to stop, and a stop command is sent to the master inverter. When the operation ready signal is the closing operation ready signal, the closing operation is performed on the slave brake mechanism when the timer duration reaches the fourth preset duration and no operation command is received.

9. A brake mechanism control device, characterized in that, include: The first adjustment module is used to adjust the host operating parameters of the host frequency inverter according to the received control instructions; The first processing module is used to maintain the state of the master brake mechanism and wait for the operation ready signal sent by the slave inverter when the master operating parameters meet the operating conditions for the master brake mechanism; wherein, the operation ready signal indicates that the slave operating parameters of the slave inverter meet the operating conditions for the slave brake mechanism. The first control module is used to execute the control operation corresponding to the control command on the master brake mechanism after receiving the operation ready signal, and to send the operation command to the slave frequency converter so that the slave frequency converter executes the control operation on the slave brake mechanism.

10. An electronic device, characterized in that, include: Memory, used to store computer programs; A processor, configured to execute the computer program to implement the steps of the brake mechanism control method according to any one of claims 1 to 8.

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