High-voltage frequency conversion system control method for crusher load and high-voltage frequency conversion system

Abstract

The invention discloses a high-voltage frequency conversion system control method and system for crusher load, and the method comprises the steps: collecting a first current value of a motor in real time in the process that the motor drives the crusher to work, and controlling a high-voltage frequency converter to be disconnected with the motor when the first current value reaches a preset protection threshold value, the crusher is driven to work through the inertia of the motor; and when the disconnection between the high-voltage frequency converter and the motor reaches a preset duration, controlling the high-voltage frequency converter and the motor to be connected again, collecting a second current value of the motor in the process that the motor drives the crusher to work, and if the second current value does not reach a preset protection threshold value, controlling the high-voltage frequency conversion system to continuously drag the crusher load to operate. According to the method and the system, tripping is not carried out when the short-time current value of the motor reaches the preset protection threshold value, so that the continuity of a crushing process can be ensured under the condition of ensuring the safety of the system.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, and in particular to a high-voltage frequency conversion system control method and a high-voltage frequency conversion system for crusher loads. Background Technology

[0002] A crusher is a common type of engineering machinery, mainly used for crushing various hard materials, such as stones and concrete. Its working principle involves using power to drive the crusher to rotate. After the material is fed into the crushing chamber, it is crushed by hammers or cutters through impact, shearing, and other crushing actions.

[0003] The specific workflow is as follows: After entering the crusher, the material is fed into the crushing chamber through the feeding device. In the crushing chamber, the material collides with the rotating crusher and is struck and impacted by the high-speed rotating hammers or blades. The material breaks and is crushed after being subjected to impact force. The crushed material is then subjected to the action of the surrounding crushers, and is continuously crushed and impacted until the desired crushing effect is achieved. The crushed material is sent to the discharge device, where it is screened and classified by devices such as vibrating screens to separate the material that meets the requirements. The material that meets the requirements is discharged through the discharge port, while the material that does not meet the requirements re-enters the crushing chamber for secondary crushing.

[0004] Through the above-described workflow, the crusher can crush or pulverize various hard materials and is widely used in engineering fields such as mining, construction, and highways. The crushing process is powered by a transmission device (such as a frequency converter), while the control system monitors and controls the crusher's operating status.

[0005] In the existing technology, when the frequency converter drives the crusher, if the crusher is overloaded, the current will often increase dramatically. When the surge current exceeds the overcurrent protection value of the frequency converter, the frequency converter will trip (the frequency converter will be disconnected from the main power supply), causing the entire crushing process to stop and reducing the continuity of the production process. Summary of the Invention

[0006] In view of this, embodiments of the present invention provide a high-voltage variable frequency system control method and a high-voltage variable frequency system for crusher loads, which does not trip when the short-time current value of the motor reaches a preset protection threshold, thereby ensuring the continuity of the crushing process while ensuring system safety.

[0007] On one hand, embodiments of the present invention provide a high-voltage variable frequency system control method for a crusher load, the high-voltage variable frequency system comprising: a high-voltage variable frequency converter, a motor, and a crusher, wherein one end of the motor is connected to the high-voltage variable frequency converter, and the other end of the motor is connected to the crusher; the method comprises: During the operation of the crusher driven by the motor, the first current value of the motor is collected in real time. When the first current value reaches the preset protection threshold, the high-voltage frequency converter is controlled to disconnect from the motor so that the crusher can be driven by the inertia of the motor. The preset protection threshold is set based on the overcurrent protection value when the high-voltage frequency converter trips, so that when the current value of the motor reaches the preset protection threshold, the high-voltage frequency converter disconnects from the motor and the high-voltage frequency converter does not trip. When the high-voltage frequency converter is disconnected from the motor for a preset time, the high-voltage frequency converter is reconnected to the motor, and the second current value of the motor is collected during the operation of the crusher driven by the motor. If the second current value does not reach the preset protection threshold, the high-voltage frequency converter system is controlled to continue to drive the crusher load.

[0008] Optionally, the method further includes: if the second current value reaches the preset protection threshold, controlling the high-voltage frequency converter to trip, outputting the expected fault cause that caused the high-voltage frequency converter to trip, and issuing a fault alarm, wherein the expected fault cause is: the crusher load exceeds the processing capacity, phase-to-phase short circuit or output terminal grounding fault.

[0009] Optionally, the high-voltage frequency converter system further includes: a speed encoder for detecting the motor speed; after the high-voltage frequency converter is disconnected from the motor, the method further includes: The speed encoder detects the rotational speed of the motor and calculates the rate at which the rotational speed of the motor decreases per unit time. If the rate of decrease per unit time reaches a preset change threshold, the high-voltage frequency converter is controlled to trip, and the expected cause of the fault is determined to be that the crusher load exceeds its processing capacity; and, Based on the rate of decrease per unit time, auxiliary processing suggestions are generated, which include at least: a description of the crusher load and suggested processing measures.

[0010] Optionally, after calculating the rate at which the motor's rotational speed decreases per unit time, the method further includes: Based on the rate at which the motor's rotational speed decreases per unit time and the motor's current rotational speed, calculate the expected time it will take for the motor to stop rotating from its current rotational speed. The preset duration is set based on the expected consumption time so that the motor can maintain operation based on inertia within the preset duration, wherein the preset duration is less than or equal to the expected consumption time.

[0011] Optionally, the method further includes setting the preset duration based on the following: Obtain the current operating frequency of the high-voltage frequency converter system, and determine the working cycle based on the current operating frequency; The preset duration is set based on the work cycle so that the motor can maintain operation based on inertia within the preset duration, wherein the preset duration is a positive integer multiple of the work cycle.

[0012] Optionally, the method further includes: setting the preset protection threshold based on the overcurrent protection value when the high-voltage frequency converter trips and the rated current value of the electronic components to be protected in the high-voltage frequency converter, so that the preset protection threshold is less than or equal to the overcurrent protection value, and when the motor current value reaches the preset protection threshold, the operating current of the electronic components is less than its rated current value.

[0013] Optionally, the preset protection threshold includes at least a first protection threshold and a second protection threshold, and satisfies that the first protection threshold < the second protection threshold. When the first current value reaches the preset protection threshold, controlling the high-voltage frequency converter to disconnect from the motor includes: When the first current value reaches the first protection threshold, it is determined that the first current value has reached the preset protection threshold, and the high-voltage frequency converter is controlled to disconnect from the motor. If the second current value does not reach the preset protection threshold, the high-voltage frequency converter system is controlled to continue driving the crusher load, including: If the second current value does not reach the second protection threshold, it is determined that the second current value has not reached the preset protection threshold, and the high-voltage frequency converter is controlled to continue to drive the crusher load until the crushing task is completed; or, when the second current value reaches the second protection threshold, the high-voltage frequency converter is controlled to trip. If the second current value reaches the preset protection threshold, the high-voltage frequency converter is controlled to trip, including: If the second current value reaches the second protection threshold, then it is determined that the second current value has reached the preset protection threshold, and the high-voltage frequency converter is controlled to trip.

[0014] Optionally, the high-voltage frequency converter is electrically connected to the motor, and the motor is mechanically connected to the crusher. The high-voltage frequency converter includes a control unit and a power unit, and the power unit has an IGBT tube for controlling the high-voltage frequency converter and the motor to be turned on or off. When the first current value reaches a preset protection threshold, the high-voltage frequency converter is disconnected from the motor, including: When the first current value reaches the preset protection threshold, the control unit of the high-voltage frequency converter sends a blocking pulse command to the power unit, and controls the IGBT in the power unit to turn off based on the blocking pulse command, so as to disconnect the electrical connection between the high-voltage frequency converter and the motor. After a preset time has elapsed since the high-voltage frequency converter was disconnected from the motor, the system reconnects the high-voltage frequency converter to the motor, including: After the high-voltage frequency converter is disconnected from the motor for a preset period of time, the control unit of the high-voltage frequency converter sends a control pulse command to the power unit, and controls the IGBT tube in the power unit to turn on based on the control pulse command, so that the high-voltage frequency converter can be reconnected to the motor.

[0015] Optionally, the high-voltage frequency converter further includes: a counter, the counter being used to count the number of times the high-voltage frequency converter is connected to the motor; after the second current value reaches the second protection threshold, the method further includes: The counter is used to count the number of times the high-voltage frequency converter is connected to the motor. If the number of counts reaches a preset threshold, then the second current value is determined to have reached the preset protection threshold. If the number of counts does not reach the preset threshold, then it is determined that the second current value has not reached the preset protection threshold.

[0016] On the other hand, embodiments of the present invention provide a high-voltage frequency converter system for a crusher load, comprising: a high-voltage frequency converter, a motor, and a crusher, wherein one end of the motor is connected to the high-voltage frequency converter, and the other end of the motor is connected to the crusher; the high-voltage frequency converter system is controlled to drive the crusher load based on the method described in any one of the above.

[0017] The high-voltage frequency converter control method and system for crusher load provided in this invention collects the first current value of the motor in real time during the operation of the crusher driven by the motor. When the first current value reaches a preset protection threshold, the high-voltage frequency converter is disconnected from the motor so that the crusher can be driven by the inertia of the motor. The preset protection threshold is set based on the overcurrent protection value when the high-voltage frequency converter trips, so that when the current value of the motor reaches the preset protection threshold, the high-voltage frequency converter is disconnected from the motor and the high-voltage frequency converter does not trip. When the high-voltage frequency converter is disconnected from the motor for a preset time, it is controlled to reconnect to the motor and the second current value of the motor during the operation of the crusher is collected. If the second current value does not reach the preset protection threshold, the high-voltage frequency converter system is controlled to continue driving the crusher load. This method and system do not trip when the short-term current value of the motor reaches the preset protection threshold, thus ensuring the continuity of the crushing process while ensuring system safety.

[0018] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings.

[0019] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0020] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0021] Figure 1 A flowchart of a high-voltage variable frequency system control method for a crusher load provided in an embodiment of the present invention; Figure 2 A block diagram of a high-voltage frequency conversion system for a crusher load provided in an embodiment of the present invention; Figure 3 A block diagram of another high-voltage frequency conversion system for a crusher load provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of a high-voltage frequency converter system provided in an embodiment of the present invention. Detailed Implementation

[0022] The technical solution of this patent application will be explained and described below with reference to the accompanying drawings and specific embodiments. The embodiments are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0023] like Figure 1 As shown, one embodiment of this patent application provides a high-voltage variable frequency system control method for a crusher load, such as... Figure 2 The high-voltage frequency converter system 20 shown includes: a high-voltage frequency converter 201, a motor 202, and a crusher 203. One end of the motor 202 is connected to the high-voltage frequency converter 201, and the other end of the motor 202 is connected to the crusher 203. The method includes steps 101-102. Step 101: During the operation of the crusher driven by the motor, the first current value of the motor is collected in real time. When the first current value reaches the preset protection threshold, the high-voltage frequency converter is disconnected from the motor so that the crusher can be driven by the inertia of the motor. The preset protection threshold is set based on the overcurrent protection value when the high-voltage frequency converter trips, so that when the current value of the motor reaches the preset protection threshold, the high-voltage frequency converter is disconnected from the motor and the high-voltage frequency converter does not trip. Step 102: When the high-voltage frequency converter is disconnected from the motor for a preset time, the high-voltage frequency converter is reconnected to the motor, and the second current value of the motor is collected during the operation of the crusher driven by the motor. If the second current value does not reach the preset protection threshold, the high-voltage frequency converter system is controlled to continue to drive the crusher load.

[0024] In this embodiment, by reasonably setting the preset protection threshold of the motor current, the high-voltage frequency converter can be disconnected from the motor when the motor current value reaches the preset protection threshold, and the high-voltage frequency converter will not trip. This allows the huge inertia of the crusher rotor to crush the load, ensuring the safety of the high-voltage frequency conversion system while ensuring the continuity of the crushing process and ensuring work efficiency.

[0025] Figure 4 This is a schematic diagram of a high-voltage frequency converter system provided in an embodiment of the present invention. The diagram schematically shows the connection relationship between key equipment such as the high-voltage frequency converter, motor, and PLC. The first and second current values ​​of the motor mentioned in the above embodiment can be determined by... Figure 4 The output current was detected at the "output current detection" point above. Figure 4 The “Output Detection” point below is used to detect the output voltage value of the high-voltage frequency converter (that is, the input voltage value of the motor).

[0026] In the above embodiments, if the second current value reaches the preset protection threshold, the high-voltage frequency converter is controlled to trip, and the expected fault cause that caused the high-voltage frequency converter to trip is output and a fault alarm is issued. The expected fault cause is: the crusher load exceeds the processing capacity (indicating that the load is too large to be crushed by the inertia of the crusher rotor), phase-to-phase short circuit or output terminal grounding fault.

[0027] Through the above embodiments, if the second current value of the motor is still not lower than the preset protection threshold after the high-voltage frequency converter is reconnected to the motor, it indicates that the current is not too high for a short time. It may be because the crusher load exceeds the processing capacity, there is a phase-to-phase short circuit or a grounding fault at the output terminal. In order to ensure the safety of the system, trip protection is required and a fault alarm is issued to remind the staff to investigate the cause of the fault in a timely manner.

[0028] To ensure system safety, after a high-voltage frequency converter trips, a rigorous fault diagnosis procedure is required to pinpoint and eliminate the fault before power can be restored. In existing technologies, a short-term increase in motor current to the overcurrent protection value will trigger the high-voltage frequency converter to trip, which can easily affect work efficiency. The technical solution provided in this embodiment, when the motor current value is first detected to reach the preset protection threshold, assumes that it may be caused by a short-term current increase. It first disconnects the connection between the high-voltage frequency converter and the motor, and the high-voltage frequency converter does not trip. When the high-voltage frequency converter and the motor are reconnected, the motor current value still does not decrease (this process can be repeated once or multiple times) until the condition that tripping is indeed necessary is met, and then the converter trips. This method can avoid the impact of continuous high current values ​​on the system, ensuring system safety, and also avoid unnecessary tripping of the high-voltage frequency converter, ensuring the continuity of the crushing process and improving work efficiency.

[0029] In another embodiment, the high-voltage frequency converter system further includes: a speed encoder for detecting the motor speed; and after controlling the high-voltage frequency converter to disconnect from the motor, the method further includes: The speed encoder detects the rotational speed of the motor and calculates the rate at which the rotational speed of the motor decreases per unit time. If the rate of decrease per unit time reaches a preset change threshold, the high-voltage frequency converter is controlled to trip, and the expected cause of the fault is determined to be that the crusher load exceeds its processing capacity; and, Based on the rate of decrease per unit time, auxiliary processing suggestions are generated, which include at least: a description of the crusher load and suggested processing measures.

[0030] In this embodiment, by adding a speed encoder for detecting motor speed, the motor speed can be detected, and the rate of decrease of motor speed per unit time can be calculated. If the rate of decrease is too fast (for example, reaching a preset change threshold), it is very likely that the crusher load is too large and exceeds the processing capacity, which may lead to a jam. At this time, the high-voltage frequency converter can be directly controlled to trip for protection, and the expected cause of the fault can be identified as the crusher load exceeding the processing capacity.

[0031] Once it is determined that the fault is caused by the crusher overloading its processing capacity, it is likely necessary to remind staff to dispatch specialized equipment for handling. To facilitate staff handling, the load situation can be estimated based on the rate at which the motor speed decreases per unit time, combined with an AI model, and auxiliary handling suggestions can be generated and sent to the terminal device bound to the staff. The auxiliary handling suggestions can include a description of the load and suggested handling measures for staff reference.

[0032] The preset duration mentioned in the above embodiments is crucial for the continuity and efficiency of the crushing process and needs to be set appropriately. Two methods for setting the preset duration are provided below, which can be selected according to needs: Method 1: Dynamically set preset duration (1) After calculating the rate at which the speed of the motor decreases per unit time, the expected time it takes for the motor to stop rotating from its current speed can be calculated based on the rate at which the speed of the motor decreases per unit time and the current speed of the motor. (2) Set the preset duration based on the expected consumption time so that the motor can maintain operation based on inertia within the preset duration, wherein the preset duration is less than or equal to the expected consumption time.

[0033] Method 2: Preset duration static setting (1) Obtain the current operating frequency of the high-voltage frequency converter system, and determine the working cycle based on the current operating frequency; (2) The preset duration is set based on the working cycle so that the motor can maintain operation based on inertia within the preset duration, wherein the preset duration is a positive integer multiple of the working cycle.

[0034] Regarding the two preset duration setting methods mentioned above, the dynamic setting method calculates different expected consumption times based on the current motor speed and the rate of decrease per unit time, thus resulting in different preset durations. In contrast, the static setting method sets a preset duration that is a fixed multiple of the working cycle after the working cycle of the high-voltage frequency converter is determined, such as 2 working cycles, 3 working cycles, etc.

[0035] The method described in any of the above embodiments may further include: setting the preset protection threshold based on the overcurrent protection value when the high-voltage frequency converter trips and the rated current value of the electronic components to be protected in the high-voltage frequency converter, so that the preset protection threshold is less than or equal to the overcurrent protection value, and when the motor current value reaches the preset protection threshold, the operating current of the electronic components is less than its rated current value.

[0036] In this embodiment, by reasonably setting the preset protection threshold, it can be ensured that the high-voltage frequency converter does not trip when the motor current reaches the preset protection threshold, and the operating current of the electronic components is also below their rated current value, thereby ensuring the safety of the electronic components. The electronic components can be relatively expensive and easily damaged components such as IGBT transistors.

[0037] Specifically, when the preset protection threshold is set to be less than the overcurrent protection value, the high-voltage frequency converter will not trip when the motor current reaches the preset protection threshold since it has not yet reached the overcurrent protection value of the high-voltage frequency converter. When the preset protection threshold is set to be equal to the overcurrent protection value, the high-voltage frequency converter will, in principle, trip when the motor current reaches the preset protection threshold. This can be achieved by modifying the control logic of the frequency converter. When the motor current reaches the preset protection threshold (overcurrent protection value), the connection between the high-voltage frequency converter and the motor will be disconnected first, instead of the frequency converter tripping. This ensures that the high-voltage frequency converter will not trip in this situation.

[0038] In another embodiment, the preset protection threshold includes at least a first protection threshold and a second protection threshold, and satisfies that the first protection threshold < the second protection threshold. When the first current value reaches the preset protection threshold, controlling the high-voltage frequency converter to disconnect from the motor includes: When the first current value reaches the first protection threshold, it is determined that the first current value has reached the preset protection threshold, and the high-voltage frequency converter is controlled to disconnect from the motor. If the second current value does not reach the preset protection threshold, the high-voltage frequency converter system is controlled to continue driving the crusher load, including: If the second current value does not reach the second protection threshold, it is determined that the second current value has not reached the preset protection threshold, and the high-voltage frequency converter is controlled to continue to drive the crusher load until the crushing task is completed; or, when the second current value reaches the second protection threshold, the high-voltage frequency converter is controlled to trip. If the second current value reaches the preset protection threshold, the high-voltage frequency converter is controlled to trip, including: If the second current value reaches the second protection threshold, then it is determined that the second current value has reached the preset protection threshold, and the high-voltage frequency converter is controlled to trip.

[0039] In this embodiment, the preset protection threshold can be set to multiple protection thresholds, not limited to the first protection threshold and the second protection threshold mentioned above. In practice, multiple protection thresholds with different levels can be set.

[0040] When the high-voltage frequency converter is first connected to the motor, the motor's first current value is compared with the lower first protection threshold to determine whether the preset protection threshold has been reached. When the high-voltage frequency converter is disconnected from the motor for a preset time and then reconnected, the motor's second current value is compared with the higher second protection threshold to determine whether the preset protection threshold has been reached. In other words, by setting multiple different protection thresholds, different protection thresholds with different levels are used at different stages as the standard for determining whether the preset protection threshold has been reached. Compared with a single protection threshold, this method can attempt to complete the load breakage test under different motor current limits while ensuring system safety.

[0041] It should be noted that the high-voltage frequency converter is electrically connected to the motor, and the motor is mechanically connected to the crusher. The high-voltage frequency converter includes a control unit and a power unit. The power unit has an IGBT tube for controlling the high-voltage frequency converter and the motor to turn on or off.

[0042] When the first current value reaches a preset protection threshold, the high-voltage frequency converter is disconnected from the motor, including: When the first current value reaches the preset protection threshold, the control unit of the high-voltage frequency converter sends a blocking pulse command to the power unit, and controls the IGBT in the power unit to turn off based on the blocking pulse command, so as to disconnect the electrical connection between the high-voltage frequency converter and the motor. After a preset time has elapsed since the high-voltage frequency converter was disconnected from the motor, the system reconnects the high-voltage frequency converter to the motor, including: After the high-voltage frequency converter is disconnected from the motor for a preset period of time, the control unit of the high-voltage frequency converter sends a control pulse command to the power unit, and controls the IGBT tube in the power unit to turn on based on the control pulse command, so that the high-voltage frequency converter can be reconnected to the motor.

[0043] In this embodiment, the control unit of the high-voltage frequency converter sends a blocking pulse command or a control pulse command to the power unit to control the IGBT transistors in the power unit to turn off or on, thereby controlling the disconnection or connection of the electrical connection between the high-voltage frequency converter and the motor. This can be achieved through simple software control logic, resulting in a low implementation cost and ease of implementation.

[0044] In another embodiment, the high-voltage frequency converter further includes: a counter for counting the number of times the high-voltage frequency converter is connected to the motor; after the second current value reaches the second protection threshold, the method further includes: The counter is used to count the number of times the high-voltage frequency converter is connected to the motor. If the number of counts reaches a preset threshold, then the second current value is determined to have reached the preset protection threshold. If the number of counts does not reach the preset threshold, then it is determined that the second current value has not reached the preset protection threshold.

[0045] In this embodiment, a counter and a preset number of counts threshold can be set. After the second current value reaches the second protection threshold, it is not immediately considered that the second current value has reached the tripping condition of the high-voltage frequency converter. It is necessary to continue to judge whether the count has reached the preset number of counts threshold. If it has not reached the threshold, the high-voltage frequency converter will not be controlled to trip, and the load breaking will continue. Only after several attempts are still unable to complete the breaking will it be considered that the load exceeds the processing capacity, and then the high-voltage frequency converter will be controlled to trip.

[0046] The high-voltage variable frequency drive (VFD) system control method for a crusher load provided in this invention collects the first current value of the motor in real time during the operation of the crusher driven by the motor. When the first current value reaches a preset protection threshold, the high-voltage VFD is disconnected from the motor to allow the crusher to operate using the motor's inertia. The preset protection threshold is set based on the overcurrent protection value of the high-voltage VFD when it trips, ensuring that the VFD does not trip when the motor current reaches the preset protection threshold. When the disconnection between the VFD and the motor reaches a preset duration, the VFD is reconnected to the motor, and a second current value of the motor during the operation of the crusher is collected. If the second current value does not reach the preset protection threshold, the high-voltage VFD system continues to drive the crusher load. This method does not trip when the motor's short-term current value reaches the preset protection threshold, ensuring the continuity of the crushing process while guaranteeing system safety.

[0047] On the other hand, embodiments of the present invention provide a high-voltage frequency conversion system 20, such as Figure 2 As shown, it includes: a high-voltage frequency converter 201, a motor 202 and a crusher 203. One end of the motor 202 is connected to the high-voltage frequency converter 201, and the other end of the motor 202 is connected to the crusher 203. The high-voltage frequency converter system 20 can be controlled to drive the crusher load based on the method in any of the above embodiments.

[0048] This invention also provides a high-voltage frequency converter system 20, such as... Figure 3 As shown, it also includes: counter 204 and speed encoder 205.

[0049] The counter 204 is used to count the number of times the high-voltage frequency converter 201 is connected to the motor 202. Speed ​​encoder 205 is used to detect the rotational speed of motor 202.

[0050] It should be noted that the content of the method embodiments and system embodiments provided in this patent application corresponds one-to-one with each other. The content involved in any embodiment can be referenced or combined with other embodiments to form part of that embodiment. For ease of description, this patent application focuses on explaining the method embodiments. The description of relevant technical features and solutions of the system, electronic device, and computer-readable storage medium embodiments can be referred to the relevant content in the method embodiments.

[0051] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, apparatus, systems, electronic devices, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage and optical storage) containing computer-usable program code.

[0052] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0053] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0054] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A high-voltage variable frequency system control method for crusher loads, characterized in that, The high-voltage frequency conversion system includes: a high-voltage frequency converter, a motor, and a crusher. One end of the motor is connected to the high-voltage frequency converter, and the other end of the motor is connected to the crusher. During the operation of the crusher driven by the motor, the first current value of the motor is collected in real time. When the first current value reaches the preset protection threshold, the high-voltage frequency converter is controlled to disconnect from the motor so that the crusher can be driven by the inertia of the motor. The preset protection threshold is set based on the overcurrent protection value when the high-voltage frequency converter trips, so that when the current value of the motor reaches the preset protection threshold, the high-voltage frequency converter disconnects from the motor and the high-voltage frequency converter does not trip. When the high-voltage frequency converter is disconnected from the motor for a preset time, the high-voltage frequency converter is reconnected to the motor, and the second current value of the motor is collected during the operation of the crusher driven by the motor. If the second current value does not reach the preset protection threshold, the high-voltage frequency converter system is controlled to continue to drive the crusher load.

2. The method according to claim 1, characterized in that, The method further includes: If the second current value reaches the preset protection threshold, the high-voltage frequency converter is controlled to trip, and the expected fault cause that caused the high-voltage frequency converter to trip is output and a fault alarm is issued. The expected fault cause is: the crusher load exceeds the processing capacity, phase-to-phase short circuit or output terminal grounding fault.

3. The method according to claim 1, characterized in that, The high-voltage frequency converter system further includes: a speed encoder for detecting the motor speed; and after the high-voltage frequency converter is disconnected from the motor, the method further includes: The speed encoder detects the rotational speed of the motor and calculates the rate at which the rotational speed of the motor decreases per unit time. If the rate of decrease per unit time reaches a preset change threshold, the high-voltage frequency converter is controlled to trip, and the expected cause of the fault is determined to be that the crusher load exceeds its processing capacity; and, Based on the rate of decrease per unit time, auxiliary processing suggestions are generated, which include at least: a description of the crusher load and suggested processing measures.

4. The method according to claim 3, characterized in that, After calculating the rate at which the motor's rotational speed decreases per unit time, the method further includes: Based on the rate at which the motor's rotational speed decreases per unit time and the motor's current rotational speed, calculate the expected time it will take for the motor to stop rotating from its current rotational speed. The preset duration is set based on the expected consumption time so that the motor can maintain operation based on inertia within the preset duration, wherein the preset duration is less than or equal to the expected consumption time.

5. The method according to claim 1, characterized in that, The method further includes setting the preset duration based on the following method: Obtain the current operating frequency of the high-voltage frequency converter system, and determine the working cycle based on the current operating frequency; The preset duration is set based on the work cycle so that the motor can maintain operation based on inertia within the preset duration, wherein the preset duration is a positive integer multiple of the work cycle.

6. The method according to claim 1, characterized in that, The method further includes: The preset protection threshold is set according to the overcurrent protection value when the high-voltage frequency converter trips and the rated current value of the electronic components to be protected in the high-voltage frequency converter, so that the preset protection threshold is less than or equal to the overcurrent protection value, and when the motor current value reaches the preset protection threshold, the operating current of the electronic components is less than its rated current value.

7. The method according to claim 2, characterized in that, The preset protection threshold includes at least a first protection threshold and a second protection threshold, and satisfies that the first protection threshold < the second protection threshold. When the first current value reaches the preset protection threshold, the high-voltage frequency converter is controlled to disconnect from the motor, including: When the first current value reaches the first protection threshold, it is determined that the first current value has reached the preset protection threshold, and the high-voltage frequency converter is controlled to disconnect from the motor. If the second current value does not reach the preset protection threshold, the high-voltage frequency converter system is controlled to continue driving the crusher load, including: If the second current value does not reach the second protection threshold, it is determined that the second current value has not reached the preset protection threshold, and the high-voltage frequency converter is controlled to continue to drive the crusher load until the crushing task is completed; or, when the second current value reaches the second protection threshold, the high-voltage frequency converter is controlled to trip. If the second current value reaches the preset protection threshold, the high-voltage frequency converter is controlled to trip, including: If the second current value reaches the second protection threshold, then it is determined that the second current value has reached the preset protection threshold, and the high-voltage frequency converter is controlled to trip.

8. The method according to claim 1, characterized in that, The high-voltage frequency converter is electrically connected to the motor, and the motor is mechanically connected to the crusher. The high-voltage frequency converter includes a control unit and a power unit. The power unit has an IGBT tube for controlling the high-voltage frequency converter and the motor to turn on or off. When the first current value reaches a preset protection threshold, the high-voltage frequency converter is disconnected from the motor, including: When the first current value reaches the preset protection threshold, the control unit of the high-voltage frequency converter sends a blocking pulse command to the power unit, and controls the IGBT in the power unit to turn off based on the blocking pulse command, so as to disconnect the electrical connection between the high-voltage frequency converter and the motor. After a preset time has elapsed since the high-voltage frequency converter was disconnected from the motor, the system reconnects the high-voltage frequency converter to the motor, including: After the high-voltage frequency converter is disconnected from the motor for a preset period of time, the control unit of the high-voltage frequency converter sends a control pulse command to the power unit, and controls the IGBT tube in the power unit to turn on based on the control pulse command, so that the high-voltage frequency converter can be reconnected to the motor.

9. The method according to claim 7, characterized in that, The high-voltage frequency converter further includes a counter, which is used to count the number of times the high-voltage frequency converter is connected to the motor; after the second current value reaches the second protection threshold, the method further includes: The counter is used to count the number of times the high-voltage frequency converter is connected to the motor. If the number of counts reaches a preset threshold, then the second current value is determined to have reached the preset protection threshold. If the number of counts does not reach the preset threshold, then it is determined that the second current value has not reached the preset protection threshold.

10. A high-voltage frequency conversion system, characterized in that, include: The system includes a high-voltage frequency converter, a motor, and a crusher, wherein one end of the motor is connected to the high-voltage frequency converter and the other end of the motor is connected to the crusher. The method according to any one of claims 1 to 9 controls the high-voltage frequency conversion system to drive the crusher load.

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