Belt conveyor braking force collaborative distribution system and method, and belt conveyor

Abstract

The present application relates to a belt conveyor braking force collaborative distribution system, method and belt conveyor. The system comprises: a motor capable of generating a motor braking force and converting mechanical energy into electrical energy to output a feedback current when the belt conveyor is in a power generation working condition; a frequency converter for controlling the torque and / or speed of the motor; an energy feedback unit for delivering the electrical energy to a power grid or other equipment; a braking resistor capable of consuming the electrical energy; a mechanical brake capable of generating a mechanical braking force; and a controller for braking force distribution of the motor braking force and the mechanical braking force during braking. The present application can use motor back electromotive force and mechanical brake to jointly brake, which can avoid the deficiency that using motor braking alone is prone to causing braking accidents when power is off.

Description

Technical Field

[0001] This invention relates to the field of belt conveyor braking control technology; specifically, this invention relates to a belt conveyor power coordination distribution system, method, and belt conveyor. Background Technology

[0002] Downward-moving belt conveyors are widely used mining transportation equipment. Their operating conditions are complex. During operation, the material generates a significant amount of potential energy under its own gravity. To ensure stable operation, a braking system is needed to absorb this excess gravitational potential energy and control the operating speed. When the conveyor meets certain inclination angles and load conditions, the downward force of the material exceeds the driving force of the motor, causing the motor to switch to regenerative braking mode. More and more mining areas are beginning to use frequency conversion regenerative braking for downward-moving belt conveyors. However, regenerative braking systems require a stable power supply from the electrical system; a sudden power outage completely eliminates their braking capability, easily leading to braking accidents. Summary of the Invention

[0003] In view of this, the present invention provides a power coordination distribution system, method and belt conveyor for belt conveyors, thereby solving or at least alleviating one or more of the above-mentioned problems and other problems existing in the prior art.

[0004] To achieve the aforementioned objective, a first aspect of the present invention provides a power coordination distribution system for a belt conveyor, wherein the system comprises: When the belt conveyor is in power generation mode, the motor can generate electric motor power and convert mechanical energy into electrical energy, outputting feedback current; A frequency converter, the frequency converter being used to control the torque and / or speed of the motor; An energy feedback unit, wherein the energy feedback unit is used to transmit the electrical energy to the power grid or other equipment; A braking resistor that can dissipate the electrical energy; A mechanical brake that can generate mechanical braking force; A controller is used to distribute braking force between the electric motor power and the mechanical braking force during braking.

[0005] In the system described above, optionally, the motor is connected to the frequency converter, the frequency converter is connected to the energy feedback unit and the braking resistor, and the controller is communicatively connected to the frequency converter and the mechanical brake.

[0006] In the system described above, optionally, the controller is a PID controller, which can use the deceleration of the conveyor belt of the belt conveyor as the control target, and the PID controller adjusts the PID parameters through a neural network. The PID controller includes a gray predictor that predicts the disturbance amount for the next cycle based on historical load fluctuation data. The predicted disturbance amount is converted into an additional torque command, which is then superimposed on the torque command output by the PID controller before the next cycle. This torque command is used to control the torque of the motor. When the neural network outputs an abnormality, the PID parameter automatically switches to the backup PID parameter.

[0007] In the system described above, optionally, the braking force of the system includes the electric motor braking force and the mechanical braking force, and the controller dynamically calculates the braking force, including: When the belt conveyor is fully loaded, calculate the maximum braking circumferential force F. B =F a +F U F a For inertial force, F U To drive the circumferential force; the driving circumferential force ,in For the quality of the conveyor belt, To bear the weight of the material, The inclination angle of the belt conveyor; the inertial force ,in m For equivalent total mass, a The required deceleration of the conveyor belt; the maximum braking circumferential force F B The safety factor ranges from 1.5 to 2; When the belt conveyor is unloaded or lightly loaded, the braking force is designed according to the maximum downward force; Furthermore, the braking force satisfies the frictional transmission limit of Euler's formula, and the design benchmark of the braking force includes the maximum value of the conveyor belt tension under different load conditions of the belt conveyor.

[0008] In the system described above, optionally, the braking force distribution includes: When the speed deviation of the motor does not exceed the first speed deviation threshold, the system brakes only by using the motor's power. When the speed deviation is greater than the first speed deviation threshold but not greater than the second speed deviation threshold, the controller controls the mechanical brake to dynamically compensate for the mechanical braking force and assist the electric motor in braking. When the speed deviation exceeds the second speed deviation threshold, the controller controls the mechanical brake to engage, and the braking resistor consumes the electrical energy until the speed deviation does not exceed the second speed deviation threshold. When an emergency stop is required for the belt conveyor, the controller controls the mechanical brake to engage, and the braking resistor consumes electrical energy until the belt conveyor stops.

[0009] In the system described above, optionally, the mechanical brake is a normally closed disc brake, the motor is a permanent magnet synchronous motor, the frequency converter is a four-quadrant frequency converter, the frequency converter supports space vector pulse width modulation algorithm, the energy feedback unit supports adaptive adjustment of DC bus voltage, and the braking resistor has redundant backup.

[0010] Optionally, in the system described above, the system further includes: The encoder is used to verify the deviation between the operating speed of the belt conveyor and the motor speed in real time. A weighing sensor is used to collect load information of the belt conveyor. The hydraulic pressure sensor acquires the hydraulic pressure signal of the mechanical brake. The system includes a dual-power hydraulic source, comprising a lubricating oil pump and a pressure oil pump that serve as backups for each other. The dual-power hydraulic source is mechanically driven by the drive shaft of the belt conveyor and can maintain the hydraulic pressure of the mechanical brake even in the event of a power outage. Furthermore, the encoder, the weighing sensor, the hydraulic pressure sensor are communicatively connected to the controller, the controller is communicatively connected to the dual-power hydraulic source, and the dual-power hydraulic source is connected to the mechanical brake.

[0011] To achieve the aforementioned objective, a second aspect of the present invention provides a method for power coordinated distribution using a belt conveyor mechanism of any of the systems described in the first aspect above.

[0012] Optionally, in the method described above, the method includes: The real-time operating conditions of the belt conveyor are collected. The braking force is calculated dynamically. The braking force distribution is performed in real time, and the braking force distribution curve is output. The dynamic calculation of the braking force includes: When the belt conveyor is fully loaded, calculate the maximum braking circumferential force F. B =F a +F U F a For inertial force, F U To drive the circumferential force; the driving circumferential force ,in For the quality of the conveyor belt, To bear the weight of the material, The inclination angle of the belt conveyor; the inertial force ,in m For equivalent total mass, a The required deceleration of the conveyor belt; the maximum braking circumferential force F B The safety factor ranges from 1.5 to 2; When the belt conveyor is unloaded or lightly loaded, the braking force is designed according to the maximum downward force; Furthermore, the braking force satisfies the frictional transmission limit of Euler's formula, and the design reference of the braking force includes the maximum value of the conveyor belt tension under different load conditions of the belt conveyor; The braking force distribution includes: When the speed deviation does not exceed the first speed deviation threshold, braking is performed by the motor braking module, and the electrical energy is fed back to the power grid. The mechanical braking module does not participate in braking. When the speed deviation is greater than the first speed deviation threshold but not greater than the second speed deviation threshold, the mechanical braking module dynamically compensates for the braking force to assist the motor braking module in braking. When the speed deviation exceeds the second speed deviation threshold, the mechanical brake engages, and the braking resistor consumes electrical energy until the speed deviation does not exceed the second speed deviation threshold. When an emergency stop is required for the belt conveyor, the mechanical brake engages, and the braking resistor consumes electrical energy until the belt conveyor stops. Wherein, the first speed deviation threshold is 5% of the rated speed, and the second speed deviation threshold is 10% of the rated speed.

[0013] To achieve the aforementioned objectives, a third aspect of the present invention provides a belt conveyor having a system as described in any of the first aspects above.

[0014] The belt conveyor power distribution system of the present invention uses the back electromotive force of the motor and the mechanical brake together for braking, which avoids the inadequacy of losing braking ability when the motor brake is used alone when the power is cut off.

[0015] The present invention further provides a power coordination distribution method for a belt conveyor using the power coordination distribution system of the belt conveyor of the present invention, and therefore the method also has the above-mentioned advantages.

[0016] The present invention further provides a belt conveyor having the power coordination distribution system of the belt conveyor mechanism of the present invention, and therefore the belt conveyor also has the above-mentioned advantages. Attached Figure Description

[0017] The disclosure of this invention will become more apparent from the accompanying drawings. It should be understood that these drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. In the drawings: Figure 1 This is a schematic block diagram of an embodiment of the power cooperative distribution system for the belt conveyor mechanism of the present invention; Figure 2 This is a schematic diagram of the braking force distribution curve of an embodiment of the belt conveyor power cooperative distribution system of the present invention; Figure 3 This is a flowchart illustrating an embodiment of the power coordination distribution method for the belt conveyor mechanism of the present invention. Detailed Implementation

[0018] Referring to the accompanying drawings and specific embodiments, the structure, composition, features, and advantages of the belt conveyor power coordination distribution system, method, and belt conveyor of the present invention will be described by way of example below. However, all descriptions should not be construed as limiting the present invention in any way.

[0019] Furthermore, for any single technical feature described or implied in the embodiments mentioned herein, or any single technical feature shown or implied in the various figures, the present invention still allows for any combination or deletion of these technical features (or their equivalents) without any technical obstacle, and thus these further embodiments according to the present invention should also be considered within the scope of this description.

[0020] It should also be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features.

[0021] Figure 1 This is a schematic block diagram of an embodiment of the power cooperative distribution system for the belt conveyor mechanism of the present invention.

[0022] like Figure 1 As shown, in this embodiment, the belt conveyor includes a drive roller, a conveyor belt and material, and a drive shaft. The system includes a controller ( Figure 1 Improved BP neural network PID controller), motor ( Figure 1 Permanent magnet synchronous motor), frequency converter ( Figure 1 (Middle four-quadrant frequency converter), energy feedback unit, braking resistor ( Figure 1 (Medium braking resistor box), mechanical brake ( Figure 1The energy feedback unit includes a disc brake, a hydraulic station, an encoder, a weighing sensor, and a hydraulic pressure sensor, and is connected to the power grid. In this embodiment, the controller can be an improved BP neural network PID controller. The motor of this invention can operate in both motor and generator modes. The motor can be a permanent magnet synchronous motor, the frequency converter can be a four-quadrant frequency converter, the braking resistor can be integrated into the braking resistor box, the mechanical brake can be a disc brake, and the rated voltage of the power grid can be 380V or 660V. In different embodiments, the above selections and configurations can be designed and adjusted based on actual needs.

[0023] like Figure 1 As shown, in this embodiment, in the belt conveyor, the drive roller provides power, which, combined with the downward force of gravity generated by the material's own weight, drives the conveyor belt and the material to move. When the belt conveyor meets certain inclination angle and load conditions, the downward force of the material is greater than the driving force of the motor, and the motor enters a generator braking state.

[0024] Specifically, in this embodiment, the belt conveyor can be a downlift belt conveyor widely used in mines. During its operation, the material on the conveyor belt generates a large amount of gravitational potential energy under its own weight, requiring a braking system to absorb the excess gravitational potential energy to control the belt conveyor's operating speed. Since the downward component of the material's gravity is in the same direction as its motion, it exists as an accelerating force. When the belt conveyor meets certain inclination angle and load conditions, the downward component of the material is greater than the driving force of the motor, causing the motor speed to exceed the synchronous speed. The motor then switches to generator mode, generating a braking torque. At this time, the belt conveyor is in generator mode. In this embodiment, whether the belt conveyor is in generator mode can be determined by calculating the tight side tension F1 and the slack side tension F2 of the drive roller. If the slack side tension is greater than the tight side tension, then the circumferential force vector F of the drive roller is greater than the slack side tension. u =F1-F2<0, meaning the direction of the circumferential force is opposite to the direction of the conveyor belt, then it can be determined that the lower belt conveyor in this embodiment is in the power generation mode.

[0025] like Figure 1 As shown, in this embodiment, the motor can output three-phase power in the above-mentioned power generation state; the frequency converter can receive the three-phase power, convert it into DC power, and transmit it to the energy feedback unit through the DC bus; the frequency converter can control the motor torque and / or speed according to the torque command; the energy feedback unit can feed back the grid-connected current to the grid; the braking resistor can realize overvoltage protection, consume excess power when the frequency converter voltage exceeds the limit, and prevent overvoltage fault.

[0026] Specifically, in this embodiment, the motor can be a permanent magnet synchronous motor with high torque density, wide speed range and low speed and high torque characteristics. It can operate as a generator in the above-mentioned power generation state, converting mechanical energy into electrical energy and outputting a stable feedback current.

[0027] Specifically, in this embodiment, the frequency converter can adopt four-quadrant frequency conversion technology combined with space vector pulse width modulation (SVPWM) algorithm, and use IGBT rectifier bridge to realize bidirectional energy flow; it can convert the three-phase power generated by the motor in the generator state into DC power, and transmit it to the energy feedback unit through the DC bus to realize energy feedback to the grid or for use by other equipment, avoiding the energy consumption and heat generation of traditional resistors; it can control the motor torque and / or speed according to the torque command of the controller to dynamically adjust the motor power.

[0028] Specifically, in this embodiment, the energy feedback unit inverts the current supplied by the DC bus and feeds it back to the power grid or supplies it to other equipment, and can support adaptive adjustment of the DC bus voltage. This energy feedback unit can be connected to a 380V or 660V power grid.

[0029] Specifically, in this embodiment, the braking resistor can urgently dissipate electrical energy in situations such as grid disconnection or the need for an emergency stop of the conveyor belt, preventing overvoltage faults. The braking resistor can have redundant backups; for example, its actual power can exceed 150% of its rated power.

[0030] like Figure 1 As shown, in this embodiment, the hydraulic station can receive a pressure regulation command and deliver pressurized oil to the mechanical brake to drive the mechanical brake to work; the mechanical brake can receive a brake-holding command and brake the drive shaft through a disc spring to achieve rapid braking.

[0031] Specifically, in this embodiment, a mechanical brake, in conjunction with an electric motor brake, forms a dual-safety braking system. A normally closed disc brake can be selected, which releases the brake via hydraulic pressure and engages it via the spring force of a disc spring. When pressurized oil rushes into the brake's oil chamber, the pressure of the oil pushes the piston backward, compressing the disc spring. At this time, the brake shoes separate from the brake disc, resulting in a released state. When the oil pressure in the brake's oil chamber decreases, the disc spring gradually eliminates its compression deformation in the released state, pushing the piston forward and causing the brake shoes to press against the brake disc, resulting in an engaged state. This mechanical brake can automatically engage in the event of a power outage, and mechanical redundancy can prevent conveyor runaway accidents.

[0032] Furthermore, in this embodiment, the hydraulic station can employ a dual-power hydraulic source. A dual-pump system is used, specifically a lubricating oil pump and a pressure oil pump that serve as backups for each other, mechanically driven by the conveyor drive shaft. This system can maintain hydraulic pressure in the mechanical brake even during a power outage. This dual-power hydraulic source provides safety redundancy, further enhancing system safety.

[0033] like Figure 1 As shown, in this embodiment, the encoder sends the motor speed signal to the controller; the load cell sends the belt conveyor load signal to the controller; and the hydraulic pressure sensor sends the braking status to the controller.

[0034] Specifically, in this embodiment, the encoder can be a multi-axis encoder, which can verify the deviation between the conveyor belt speed and the motor speed in real time. The speed deviation is the difference between the actual motor speed and the rated speed. This information is provided to the controller to help the controller make decisions based on the real-time operating speed. The load sensor can collect the load information of the conveyor belt, including the real-time conveying volume, and provide it to the controller to help the controller make braking force distribution decisions based on the real-time load conditions. The hydraulic pressure sensor can collect the hydraulic pressure signal of the mechanical brake and provide it to the controller so that it can accurately grasp the braking status of the mechanical brake in real time and prevent coordination failure caused by time estimation errors. The encoder, load sensor, and hydraulic pressure sensor mentioned above can provide safety redundancy, further improving the safety of the system.

[0035] like Figure 1 As shown, in this embodiment, the controller can receive the speed signal, load signal and braking status, and perform control operations such as sending torque commands to the frequency converter, sending pressure adjustment commands to the hydraulic station, and sending brake-holding commands to the mechanical brake based on the above information.

[0036] Specifically, in this embodiment, the controller can be a PID controller combined with a neural network. The neural network can be an improved BP neural network. The controller can make decisions and control based on operating conditions such as speed information, load information, mechanical braking status, conveyor belt slope, and motor power generation status. The controller can use the conveyor belt deceleration as the control target and adjust the proportional coefficient K through the neural network. p Integral coefficient K i Differential coefficient K d The PID parameters are used to generate a braking force distribution curve in real time, dynamically adjust the braking torque, and prevent the belt conveyor from running at overspeed.

[0037] Furthermore, in this embodiment, the controller can incorporate a grey predictor for feedforward compensation to reduce the impact of disturbances such as sudden changes in material flow. The grey predictor can predict the disturbance amount for the next cycle based on historical load fluctuation data, and convert the predicted disturbance amount into an additional torque command ΔT. comp The additional torque command is superimposed on the torque command output by the PID controller in advance to offset or partially offset the effect of the interference.

[0038] Furthermore, in this embodiment, the controller has fault protection logic. If the PID parameters output by the neural network are abnormal, for example, if a proportional coefficient adjustment ΔK occurs... p If the mutation rate exceeds 50%, the system can automatically switch to the backup PID parameters.

[0039] Furthermore, in this embodiment, the controller can adjust the control target according to different operating conditions. During normal deceleration, the conveyor belt deceleration is used as the control target, for example, setting the control target to a deceleration ≤ 0.3 m / s. 2 The control objective is to reduce mechanical wear and achieve smooth deceleration, or to set other values ​​according to actual conditions. In this case, energy feedback is prioritized, and at least 70% of the energy can be recovered. At the same time, the power torque can be finely modulated through the mechanical brake to make braking smoother. When medium to high intensity braking is required, the control objective is adjusted to suppress slippage, that is, the uncontrolled acceleration and sliding of the conveyor belt under no-power conditions. In this case, the frequency converter can be controlled to output pre-torque to improve the response speed, and the mechanical brake can be controlled to release the braking force slowly. In the event of an emergency power failure, the control objective is to quickly trigger the safety brake, for example, triggering it within 0.5 seconds, or setting other standards according to actual conditions. In this case, the mechanical brake can be controlled to engage for rapid braking, and the braking resistor can be used to cut into the circuit to dissipate energy and prevent overvoltage faults.

[0040] Furthermore, in this embodiment, the controller can provide graded protection against overspeeding of the belt conveyor, and the operating speed information of the belt conveyor can be monitored in real time by the aforementioned encoder. If the motor speed deviation exceeds the first speed deviation threshold but does not exceed the second speed deviation threshold, assuming that the power generation condition within this speed range causes almost no damage to the main components and can effectively generate electricity, the motor brakes and feeds back electrical energy. At the same time, the mechanical brake dynamically compensates for the braking force, ensuring that the back electromotive force of the motor participating in braking changes smoothly under controllable power generation conditions, reducing the impact on electrical components and the power grid. If the speed deviation exceeds the second speed deviation threshold, emergency mechanical braking is triggered, the mechanical brake engages, and the braking resistor is switched to energy dissipation. Depending on the embodiment, the first speed deviation threshold and the second speed deviation threshold can be set differently. For example, in this embodiment, the first speed deviation threshold can be set to 5% of the rated speed value, and the second speed deviation threshold can be set to 10% of the rated speed value.

[0041] Figure 2 This is a schematic diagram of the braking force distribution curve of an embodiment of the power cooperative distribution system of the belt conveyor mechanism of the present invention.

[0042] Figure 2 The power distribution curve of the conveyor belt mechanism is shown. The horizontal axis represents the motor speed deviation Δn, and the vertical axis represents the braking force ratio. The units are all percentages. Figure 2 The diagram uses three different lines to represent the braking force ratios of electric motor braking, mechanical braking, and total braking force. Electric motor braking can feed electrical energy back to the grid, mechanical braking can use hydraulic disc brakes, and the total braking force is the sum of the electric motor braking force and the mechanical braking force. Therefore, the total braking force ratio is fixed at 100%, while the braking force ratios of electric motor braking and mechanical braking are their respective proportions of the total braking force.

[0043] like Figure 2 As shown, in this embodiment, the system is designed according to the ISO 5048 international standard and the GB / T 10595-2017 national standard, and the braking force has a safety margin of not less than 15%. In other embodiments, the design can be changed or adjusted according to actual conditions.

[0044] like Figure 2 As shown, in this embodiment, the braking force distribution can be divided into three cases based on the speed deviation Δn: pure regenerative braking zone, mixed braking zone, and emergency braking zone. When the speed deviation does not exceed 5% of the rated motor speed, it is in the pure regenerative braking zone, where the motor braking can reach the maximum regenerative efficiency point, and the regenerative efficiency η can reach η>95%. When the speed deviation is between 5% and 10% of the rated speed, it is in the mixed braking zone, where the motor braking is the main force and the mechanical braking is the auxiliary force. The braking force ratio of the mechanical braking can be increased as needed according to the increase in speed deviation, while the braking force ratio of the motor braking decreases accordingly. The mechanical braking can find the thermal load balance point in the mixed braking zone, where the heat generation rate and heat dissipation rate of the mechanical brake reach a dynamic balance. When the speed deviation exceeds 10% of the rated speed, it is in the emergency braking zone, where mechanical braking is the main force and the motor braking is the auxiliary force. The braking force ratio of the mechanical braking can be further increased, and can be increased as needed according to the increase in speed deviation within a certain range, while the braking force ratio of the motor braking decreases accordingly.

[0045] Specifically, in this embodiment, in the pure regenerative braking zone, motor braking is used alone, and the mechanical brake does not intervene. At this time, all the energy is fed back to the grid. In the mixed braking zone, it is assumed that the main components are hardly damaged under the power generation condition within this speed range, and effective power generation can be achieved. The motor brakes and feeds back electrical energy, while the mechanical brake dynamically compensates for the braking force, ensuring that the back electromotive force of the motor participating in braking changes smoothly under controllable power generation conditions, reducing the impact on electrical components and the power grid. In the emergency braking zone, the mechanical brake engages, and the braking resistor is switched to energy dissipation to achieve rapid braking. Once the speed deviation drops below 10%, the power generation condition is switched back, entering the mixed braking zone.

[0046] Furthermore, in this embodiment, if an emergency stop of the belt conveyor is required, an emergency mechanical brake can be triggered, the mechanical brake engages, and the braking resistor engages to dissipate energy until the belt conveyor stops. At this point, the mechanical brake can engage completely, and the braking resistor can dissipate electrical energy at maximum power.

[0047] In other embodiments, the criteria for determining the pure regenerative braking zone, mixed braking zone, and emergency braking zone can be changed according to actual design requirements. The criteria can be based on speed deviation or other factors, and the speed deviation threshold can be designed according to actual needs. Depending on the embodiment, the regenerative efficiency and heat load balance point may vary due to different system designs.

[0048] Figure 3 This is a flowchart illustrating an embodiment of the power coordination distribution method for the belt conveyor mechanism of the present invention.

[0049] Figure 3 This embodiment demonstrates the process of the method from system startup to operation control, and then to safety monitoring and shutdown, highlighting the core role of the intelligent controller combined with neural networks in the method.

[0050] like Figure 3 As shown, in this embodiment, the method includes the following steps: Step S10: System initialization, then proceed to step S20; Step S20: Sensor data is collected in real time, and then proceed to step S30; Step S30: Dynamically analyze and calculate the total braking force F, then proceed to step S40; Step S40: Use a BP neural network to make a decision on the allocation strategy, and select to proceed to one of steps S51, S52 or S53 based on the decision. Step S51: Determine pure regenerative braking and use motor braking, then proceed to step S60; Step S52: Determine hybrid braking, with motor braking as the dominant force, and then proceed to step S60; Step S53: Determine the emergency braking motor, which is controlled by mechanical braking, and then proceed to step S60; Step S60: Output the braking torque curve, then execute step S71 and / or execute step S72; Step S71: Output torque command to adjust motor braking, then return to step S20; In step S72, a pressure adjustment command is output to adjust the mechanical brake, and then the process returns to step S20.

[0051] Specifically, in this embodiment, in step S20, sensors such as speed, weighing, and hydraulic pressure can be used to collect real-time operating data. This real-time operating data can be used to calculate the tension on both sides of the drive roller of the belt conveyor, namely, the tight side tension F1 and the slack side tension F2. If the slack side tension is greater than the tight side tension, then the circumferential force vector F of the drive roller is... u =F1-F2<0, meaning the direction of the circumferential force is opposite to the direction of the conveyor belt, then it can be determined that the lower belt conveyor in this embodiment is in the power generation mode.

[0052] Specifically, in this embodiment, step S30 includes the following specific calculation method. Wherein, when the fully loaded finger conveyor's conveying capacity is not less than the rated conveying capacity, the following light load standard may have different definitions in different embodiments.

[0053] When a belt conveyor is fully loaded and transporting materials, the weight of the material dominates the braking demand, and the maximum braking circumferential force F needs to be calculated. B =F a +F U F a For inertial force, F U To drive the circumferential force. At this time, the driving circumferential force... F U Its essential function is to overcome the net downward force, that is ,in, For the quality of the conveyor belt, To bear the weight of the material, For the conveyor tilt angle, F 运行阻力 This includes all forces that impede operation, such as friction between the conveyor belt and idlers, and bearings. In downward conveying conditions, this resistance will, to some extent, offset the downward force. Inertial force. F a Used to overcome system inertia and generate the required deceleration a (Negative acceleration) enables the belt conveyor to stop safely and smoothly from a constant speed descent, achieving controllable shutdown. ,in m This is the equivalent total mass of the entire belt conveyor system (conveyor belt, material, idlers, etc.). Furthermore, the calculated maximum braking circumferential force F... B A safety factor of 1.5 to 2 should also be used.

[0054] When the belt conveyor is unloaded or lightly loaded, the risk of runaway after a power outage needs to be checked. In this case, the braking force is designed based on the maximum sliding force. Under unloaded or lightly loaded conditions, the conveyor only bears its own weight and a small amount of material. Although the sliding force is smaller, the running resistance is also lower. If the sliding force exceeds the running resistance, the belt conveyor system cannot self-lock, and the conveyor belt will continue to slide under gravity. To ensure absolute safety, neglecting running resistance, the designed braking force must be able to overcome the theoretical maximum sliding force that the belt conveyor may generate under the maximum design inclination angle and current load.

[0055] Furthermore, the braking force design should be based on the maximum conveyor belt tension under different operating conditions, and it must meet the friction transmission limit of Euler's formula, meaning the friction between the roller and the conveyor belt must not exceed the limit value to avoid slippage. During emergency braking under full load, the sudden slamming of the brakes (huge braking force) will generate a significant tension change on the drive roller. If the braking force is set too high, resulting in excessively rapid deceleration, the force may exceed the tensile strength of the conveyor belt, leading to belt breakage. Therefore, the braking force must not exceed the allowable tension of the conveyor belt and the design limits of the belt conveyor system. Under light load braking, the running resistance is relatively high. If excessive braking force is applied at this time, the conveyor belt is prone to slipping on the drive roller because the slack side tension becomes too low to meet the requirements of Euler's formula. Slippage generates high temperatures, burning the conveyor belt cover rubber.

[0056] Furthermore, determining the braking force is not a single calculation, but an iterative and verification process. First, based on the requirements of overcoming the slippage force and providing the necessary deceleration, the theoretically required braking force is initially calculated. This initially calculated braking force is then used as input to perform dynamic tension simulation on the entire belt conveyor system. If the simulation results show that the maximum tension is close to or exceeds the allowable tension of the conveyor belt, it indicates that the initially selected braking force is too large. The braking force can be reduced by decreasing the deceleration or extending the braking time, and the tension simulation should be repeated until the maximum tension is less than the allowable tension of the conveyor belt.

[0057] Specifically, in this embodiment, during steps S40-S60, the controller can make decisions based on the control strategy and intelligent control algorithm of the controller in the aforementioned embodiment, and dynamically generate a braking force distribution curve (the braking torque curve in the figure). In other embodiments, other suitable control strategies and intelligent control algorithms may also be used.

[0058] Specifically, in this embodiment, in step S71, the motor torque / speed can be dynamically adjusted by the frequency converter according to the torque command. The frequency converter can operate according to the selection and operation method of the frequency converter in the aforementioned embodiment, or it can adopt other suitable configurations and operating modes.

[0059] Specifically, in this embodiment, in step S72, a pressure adjustment command can be sent to the hydraulic device, and the hydraulic device delivers hydraulic oil to the mechanical brake according to the pressure adjustment command, thereby adjusting the oil pressure of the mechanical brake and thus adjusting the braking force of the mechanical brake.

[0060] Specifically, in this embodiment, in steps S71 and S72, the energy processing method can be adjusted according to different operating conditions through torque and pressure adjustment commands, including: under normal deceleration conditions, all energy is fed back to the grid, and the mechanical brake is on standby; under moderate overspeed conditions, energy feedback is the primary method, with mechanical braking as a secondary method, for example, 80% of the electrical energy can be fed back, and the mechanical brake pressure is in a floating state, dynamically adjusted according to demand; under severe overspeed conditions, mechanical braking is the primary method, with energy feedback as a secondary method, for example, 70% of the electrical energy can be fed back, and the mechanical brake can be fully engaged; in the event of an emergency power outage, the motor stops immediately, the mechanical brake can be fully engaged, and the braking resistor can dissipate electrical energy at maximum power. The operating condition of the belt conveyor can be determined according to the standards adopted in the aforementioned embodiments, or other suitable classification standards can be used.

[0061] Some embodiments of this invention aim to solve the problem of reasonable matching and self-adaptation of load and braking torque under long-distance, high-inertia characteristics. Some embodiments of this invention employ a method of combined braking using the motor's back electromotive force and mechanical brakes such as disc brakes, constructing a braking force collaborative distribution system and precise control method. By dynamically adjusting the braking torque through the mechanical brakes, the peak value of the gravitational potential energy component during downward movement is reduced, resulting in smoother motor operation under power generation conditions. This avoids voltage spikes and drops that could impact electrical components and the power grid. Simultaneously, it also solves problems such as impact and noise associated with mechanical braking, significantly reducing wear on the mechanical brakes.

[0062] In some embodiments of the present invention, the control strategy for regenerative braking not only meets the requirements of braking safety regulations but also optimizes the rational distribution of motor power and mechanical braking force during braking. Depending on the embodiment, different control strategies can significantly affect the regenerative braking effect; the control strategies in some embodiments of the present invention can enable the regenerative braking system to operate efficiently.

[0063] The controllers of some embodiments of the present invention may have technical advantages including at least one of the following: (1) Dynamic adaptability: The PID parameters are optimized in real time through a BP neural network to cope with the time-varying characteristics of the conveyor load; (2) Grey prediction feedforward compensation: Grey prediction compensation reduces the impact of external interference; (3) Engineering robustness: FPGA hardware acceleration + learning mechanism constraints ensure reliability; (4) Automatic decision-making based on speed deviation; (5) Multiple security mechanisms; (6) Maximize the regenerative braking ratio; (7) Mechanical braking minimization strategy.

[0064] Some embodiments of this invention are particularly suitable for precise braking control of long-distance, variable-angle downhill belt conveyors, providing high-precision execution assurance for energy feedback systems. While ensuring safe operation, it recovers as much braking energy as possible, addressing issues such as impact and slippage inherent in traditional mechanical braking through electro-hydraulic synergy. This prevents excessive braking deceleration from causing significant impact damage to the reducer gears or brake drum shaft, or excessively low braking deceleration leading to prolonged braking time and increased heat generation that could cause braking system failure due to overheating. Furthermore, by incorporating conveyor-wide dynamic analysis technology to optimize control parameters, it further improves system response speed and reliability, reduces the production cost of downhill belt conveyors, and enhances the economic benefits for enterprises.

[0065] The technical scope of this invention is not limited to the contents of the above specification. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this invention, and all such modifications and variations should fall within the scope of this invention.

Claims

1. A power cooperative distribution system for a belt conveyor mechanism, characterized in that, The system includes: When the belt conveyor is in power generation mode, the motor can generate electric motor power and convert mechanical energy into electrical energy, outputting feedback current; A frequency converter, the frequency converter being used to control the torque and / or speed of the motor; An energy feedback unit, wherein the energy feedback unit is used to transmit the electrical energy to the power grid or other equipment; A braking resistor that can dissipate the electrical energy; A mechanical brake that can generate mechanical braking force; The controller is used for distributing braking force between the electric motor power and the mechanical braking force during braking; The controller is a PID controller, which uses the deceleration of the conveyor belt as the control target. The PID controller adjusts the PID parameters through a neural network. The PID controller includes a gray predictor that predicts the disturbance amount for the next cycle based on historical load fluctuation data. The predicted disturbance amount is converted into an additional torque command, which is then superimposed on the torque command output by the PID controller before the next cycle. This torque command is used to control the torque of the motor. When the neural network outputs an abnormality, the PID parameter automatically switches to the backup PID parameter; The braking force of the system includes the electric motor braking force and the mechanical braking force, and the controller dynamically calculates the braking force, including: When the belt conveyor is fully loaded, calculate the maximum braking circumferential force F. B =F a +F U F a For inertial force, F U To drive the circumferential force; the driving circumferential force ,in For the quality of the conveyor belt, To bear the weight of the material, Let F be the inclination angle of the belt conveyor. 运行阻力 For all forces that impede operation; the inertial force Where m is the equivalent total mass, a is the required conveyor belt deceleration; the maximum braking circumferential force F B The safety factor ranges from 1.5 to 2; When the belt conveyor is unloaded or lightly loaded, the braking force is designed according to the maximum downward force; Furthermore, the braking force satisfies the frictional transmission limit of Euler's formula, and the design reference of the braking force includes the maximum value of the conveyor belt tension under different load conditions of the belt conveyor; The braking force distribution includes: When the speed deviation of the motor does not exceed the first speed deviation threshold, the system brakes only by using the motor's power. When the speed deviation is greater than the first speed deviation threshold but not greater than the second speed deviation threshold, the controller controls the mechanical brake to dynamically compensate for the mechanical braking force and assist the electric motor in braking. When the speed deviation exceeds the second speed deviation threshold, the controller controls the mechanical brake to engage, and the braking resistor consumes the electrical energy until the speed deviation does not exceed the second speed deviation threshold. When an emergency stop is required for the belt conveyor, the controller controls the mechanical brake to engage, and the braking resistor consumes electrical energy until the belt conveyor stops.

2. The belt conveyor power distribution system as described in claim 1, characterized in that, The motor is connected to the frequency converter, the frequency converter is connected to the energy feedback unit and the braking resistor, and the controller is communicatively connected to the frequency converter and the mechanical brake.

3. The power distribution system for a belt conveyor as described in claim 1, characterized in that, The mechanical brake is a normally closed disc brake, the motor is a permanent magnet synchronous motor, the frequency converter is a four-quadrant frequency converter, the frequency converter supports space vector pulse width modulation algorithm, the energy feedback unit supports adaptive adjustment of DC bus voltage, and the braking resistor has redundant backup.

4. The power distribution system for a belt conveyor as described in claim 1, characterized in that, The system also includes: The encoder is used to verify the deviation between the operating speed of the belt conveyor and the motor speed in real time. A weighing sensor is used to collect load information of the belt conveyor. The hydraulic pressure sensor acquires the hydraulic pressure signal of the mechanical brake. The system includes a dual-power hydraulic source, comprising a lubricating oil pump and a pressure oil pump that serve as backups for each other. The dual-power hydraulic source is mechanically driven by the drive shaft of the belt conveyor and can maintain the hydraulic pressure of the mechanical brake even in the event of a power outage. Furthermore, the encoder, the weighing sensor, the hydraulic pressure sensor are communicatively connected to the controller, the controller is communicatively connected to the dual-power hydraulic source, and the dual-power hydraulic source is connected to the mechanical brake.

5. A method for power distribution using a belt conveyor power distribution system as described in any one of claims 1-4.

6. The power coordination and distribution method for a belt conveyor mechanism as described in claim 5, characterized in that, The method includes: The real-time operating conditions of the belt conveyor are collected. The braking force is calculated dynamically. The braking force distribution is performed in real time, and the braking force distribution curve is output. The braking force distribution includes: When the speed deviation does not exceed the first speed deviation threshold, braking is performed by the motor braking module, and the electrical energy is fed back to the power grid. The mechanical braking module does not participate in braking. When the speed deviation is greater than the first speed deviation threshold but not greater than the second speed deviation threshold, the mechanical braking module dynamically compensates for the braking force to assist the motor braking module in braking. When the speed deviation exceeds the second speed deviation threshold, the mechanical brake engages, and the braking resistor consumes electrical energy until the speed deviation does not exceed the second speed deviation threshold. When an emergency stop is required for the belt conveyor, the mechanical brake engages, and the braking resistor consumes electrical energy until the belt conveyor stops. Wherein, the first speed deviation threshold is 5% of the rated speed, and the second speed deviation threshold is 10% of the rated speed.

7. A belt conveyor having a power distribution system for a belt conveyor mechanism as described in any one of claims 1-4.

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