Mining main inclined shaft belt conveyor and power balance adaptive control method therefor

Abstract

A mining main inclined shaft belt conveyor, comprising a head unloading roller (1), a middle unloading roller (6), and a tail roller (10), wherein a belt for conveying is wound on the head unloading roller (1), the middle unloading roller (6), and the tail roller (10); a head conveying section is formed between the head unloading roller (1) and the middle unloading roller (6); a tail conveying section is formed between the middle unloading roller (6) and the tail roller (10); a first middle driving roller (8), a second middle driving roller (7), and a third middle driving roller (9) located below the tail conveying section are sequentially arranged at the downstream portion of the middle unloading roller (6); and a first head driving roller (2) and a second head driving roller (3) located below the head conveying section are sequentially arranged at the downstream portion of the head unloading roller (1). The belt conveyor can achieve collaborative control, so that the power balance of the belt conveyor can be kept at 95% or above throughout the entire life cycle of the belt conveyor. Also provided is a power balance adaptive control method for a belt conveyor.

Description

A mine main inclined shaft belt conveyor and its power balance adaptive control method Technical Field

[0001] The present invention relates to the technical field of belt conveyors, and in particular to a mine main inclined shaft belt conveyor and a power balance adaptive control method thereof. Background Art

[0002] The main inclined shaft belt conveyor is the main transportation route of the coal mine. It is a high-power belt conveyor, and its transportation capacity directly determines the output of the entire coal mining enterprise.

[0003] However, multi-point and multi-machine belt conveyors may have limited transport capacity due to a motor running current that is too high or too low. In serious cases, this may cause equipment damage, thus affecting production.

[0004] Excessive or insufficient motor operating current is a sign of power imbalance. After a period of operation, one or more of the conveyor's drive rollers may experience varying degrees of wear. This can lead to a significant difference in the operating current of individual motors compared to others. This difference can only increase with increasing transport volume. Existing technology can only guarantee power balance during the commissioning of new equipment, but cannot achieve power balance throughout the entire life cycle of the belt conveyor.

[0005] Summary of the Invention

[0006] In view of this, the present invention provides a mining main inclined shaft belt conveyor and a power balance adaptive control method thereof, thereby solving or at least alleviating one or more of the above-mentioned problems and other problems existing in the prior art.

[0007] In order to achieve the aforementioned objectives, a first aspect of the present invention provides a mine main inclined shaft belt conveyor, wherein the belt conveyor includes a head unloading roller, an intermediate unloading roller and a tail roller, and a belt for conveying is wound around the head unloading roller, the intermediate unloading roller and the tail roller, a head conveying section is formed between the head unloading roller and the intermediate unloading roller, and a tail conveying section is formed between the intermediate unloading roller and the tail roller, and a first intermediate drive roller, a second intermediate drive roller and a third intermediate drive roller are sequentially arranged below the tail conveying section at the downstream of the intermediate unloading roller, and a first head drive roller and a second head drive roller are sequentially arranged below the head conveying section at the downstream of the head unloading roller.

[0008] In the belt conveyor as described above, optionally, the first head drive roller is located upstream of the second head drive roller, and the first head drive roller and the second head drive roller adopt a 2:1 power distribution arrangement, and the first intermediate drive roller, the second intermediate drive roller and the third intermediate drive roller adopt a 1:1:1 power distribution arrangement.

[0009] In the belt conveyor as described above, optionally, the belt conveyor has a control system, which includes a head control main station, a mid-machine control substation, and a tail control substation. The head control main station, the mid-machine control substation, and the tail control substation realize control and signal acquisition through bus communication.

[0010] In the belt conveyor as described above, optionally, the first head drive roller and the second head drive roller are located on the ground, the first intermediate drive roller, the second intermediate drive roller and the third intermediate drive roller are located underground in a coal mine, and a belt scale is provided at the tail of the belt conveyor, and the analog input and output module of the tail control substation reads the belt scale coal quantity from the belt scale to the belt scale through the belt scale controller, and a tensioning device is provided at the head of the belt conveyor, and the analog input and output module of the head control main station controls the tensioning device through the tensioning device controller, and the head control main station adjusts the tensioning force of the tensioning device according to the coal quantity on the belt scale, the tension value of the tensioning device, the current data of the motors at the first head drive roller, the second head drive roller, the first intermediate drive roller, the second intermediate drive roller and the third intermediate drive roller according to preset rules, and sends a speed given compensation signal to the inverter with the largest current difference in the motor and keeps the power balance above 95%.

[0011] In the belt conveyor as described above, optionally, the preset rule is:

[0012] Step S1: the main head control station controls the motor frequency converters of the first head drive roller, the second head drive roller, the first intermediate drive roller, the second intermediate drive roller and the third intermediate drive roller according to a given standard speed;

[0013] Step S2: acquiring in real time the coal quantity of the belt scale, the tension value of the tensioning device, and the current value of the motor inverter;

[0014] Step S3: Using the average current value of the motor inverter as a reference current, the current value of each inverter is compared with the reference current, the inverter data with the worst power balance is saved, and it is determined whether the ratio exceeds the preset power balance. If so, the process proceeds to step S4; otherwise, step S3 is repeated.

[0015] Step S4: judging whether to adjust the belt tension according to the coal quantity on the belt scale and the tensioning force of the tensioning device, if yes, proceeding to step S5, otherwise proceeding to step S6;

[0016] Step S5: the analog input / output module of the machine head control master station outputs an analog transmission current signal to the tensioning controller of the tensioning device for tension adjustment;

[0017] Step S6: Perform speed setting compensation on the inverter with the worst power balance, and determine whether the power balance of the inverter with the worst power balance is better than the previous power balance. If yes, proceed to step S7; otherwise, proceed to step S9.

[0018] Step S7: Determine whether the power balance of the inverter with the worst power balance meets the balance requirement. If yes, complete the current adjustment; otherwise, proceed to step S8;

[0019] Step S8: Repeat step S6 until the power balance of the inverter with the worst power balance meets the power balance requirement or the power balance is worse than the previous data;

[0020] Step S9: the main control station of the locomotive controls the inverter with the worst power balance according to the given standard speed plus the compensation speed, and restores the previous adjustment.

[0021] In the belt conveyor as described above, optionally, in step S6, the speed setting compensation is controlled by the head control main station according to the given standard speed minus the compensation speed to control the inverter with the worst power balance, with a delay of 20 seconds.

[0022] In order to achieve the aforementioned purpose, the second aspect of the present invention provides a power balance adaptive control method for a belt conveyor, wherein the belt conveyor includes a head unloading roller, an intermediate unloading roller and a tail roller, a belt for conveying is wound around the head unloading roller, the intermediate unloading roller and the tail roller, a head conveying section is formed between the head unloading roller and the intermediate unloading roller, a tail conveying section is formed between the intermediate unloading roller and the tail roller, and a first intermediate driving roller, a second intermediate driving roller and a third intermediate driving roller are sequentially arranged below the tail conveying section at the downstream of the intermediate unloading roller, a first head driving roller and a second head driving roller are sequentially arranged below the head conveying section at the downstream of the head unloading roller, the first head driving roller is located upstream of the second head driving roller, a belt scale is provided at the tail of the belt conveyor, and a tensioning device is provided at the head of the belt conveyor.

[0023] In addition, the belt conveyor has a control system, which includes a head control main station, a mid-machine control substation, and a tail control substation. The head control main station, the mid-machine control substation, and the tail control substation communicate to realize control and signal acquisition. The analog input and output module of the tail control substation reads the coal quantity on the belt scale from the belt scale through the belt scale controller. The analog input and output module of the head control main station controls the tensioning device through the tensioning device controller.

[0024] The method comprises the following steps:

[0025] Step S1: the main head control station controls the motor frequency converters of the first head drive roller, the second head drive roller, the first intermediate drive roller, the second intermediate drive roller, and the third intermediate drive roller according to a given standard speed;

[0026] Step S2: obtaining in real time the coal quantity weighed by the belt of the belt scale, the tension value of the tensioning device, and the current value of the motor inverter;

[0027] Step S3: Using the average current value of the motor inverter as a reference current, the current value of each inverter is compared with the reference current, the inverter data with the worst power balance is saved, and it is determined whether the ratio exceeds the preset power balance. If so, the process proceeds to step S4; otherwise, step S3 is repeated.

[0028] Step S4: judging whether to adjust the belt tension according to the coal quantity on the belt scale and the tension value of the tensioning device, if yes, proceeding to step S5, otherwise proceeding to step S6;

[0029] Step S5: the analog output of the machine head control master station sends a 4-20mA current signal to the tensioning controller of the tensioning device for tension adjustment;

[0030] Step S6: Perform speed setting compensation on the inverter with the worst power balance, and determine whether the power balance of the inverter with the worst power balance is better than the previous power balance. If yes, proceed to step S7; otherwise, proceed to step S9.

[0031] Step S7: Determine whether the power balance of the inverter with the worst power balance meets the balance requirement. If yes, complete the current adjustment; otherwise, proceed to step S8;

[0032] Step S8: Repeat step S6 until the power balance of the inverter with the worst power balance meets the power balance requirement or the power balance is worse than the previous data;

[0033] Step S9: the main control station of the locomotive controls the inverter with the worst power balance according to the given standard speed plus the compensation speed, and restores the previous adjustment.

[0034] In the method described above, optionally, in step S6, the speed setting compensation is performed by the head control master station to control the inverter with the worst power balance according to the given standard speed minus the compensation speed, with a delay of 20 seconds.

[0035] In the method as described above, optionally, it is characterized in that the first head drive roller is located upstream of the second head drive roller, and the first head drive roller and the second head drive roller adopt a 2:1 power distribution arrangement, and the first intermediate drive roller, the second intermediate drive roller and the third intermediate drive roller adopt a 1:1:1 power distribution arrangement.

[0036] In the method described above, optionally, the locomotive control main station adjusts the tension value of the tensioning device according to the coal amount on the belt scale, the tension value of the tensioning device, the current data of the motors at the first locomotive drive roller, the second locomotive drive roller, the first intermediate drive roller, the second intermediate drive roller and the third intermediate drive roller according to preset rules, and sends a speed setting compensation signal to the inverter with the largest current difference in the motor and keeps the power balance above 95%.

[0037] This invention provides a mine main inclined shaft belt conveyor and its power balance adaptive control method. The control system adjusts the tension of the tensioning device and compensates for the worst-balanced inverter speed according to preset rules based on the coal quantity measured on the belt scale, the tension value of the tensioning device, and the current value of the high-voltage inverter. This achieves a motor power balance of no less than 95%. This power balance adaptive method for the belt conveyor is implemented throughout the entire equipment lifecycle, effectively ensuring the belt conveyor's coal production. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The disclosure of the present invention will become more apparent with reference to 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 the present invention. In the drawings:

[0039] FIG1 is a schematic structural diagram of an embodiment of a main inclined shaft belt conveyor of the present invention;

[0040] FIG2 is a flow chart of an embodiment of a power balance adaptive control method according to the present invention.

[0041] Figure markings: 1-head unloading roller, 2-first head drive roller, 3-second head drive roller, 4-first redirecting roller, 5-second redirecting roller, 6-intermediate unloading roller, 7-second intermediate drive roller, 8-first intermediate drive roller, 9-third intermediate drive roller, 10-tail roller, 11-belt scale, 12-tensioning device. DETAILED DESCRIPTION

[0042] With reference to the accompanying drawings and specific embodiments, the structure, composition, characteristics and advantages of the mine main inclined shaft belt conveyor and its power balance adaptive control method of the present invention will be explained below in an illustrative manner. However, all descriptions should not be used to form any limitations on the present invention.

[0043] In addition, for any single technical feature described or implied in the embodiments mentioned in this document, or any single technical feature shown or implied in the accompanying drawings, the present invention still allows for continued arbitrary combination or deletion between these technical features (or their equivalents) without any technical obstacles, and thus it should be considered that these more embodiments according to the present invention are also within the scope of the description in this document.

[0044] It should also be noted that the terms "below" and "downstream" indicate directions or positional relationships based on the directions or positional relationships of the main inclined shaft belt conveyor and the direction of operation of the belt as shown in the accompanying drawings. They are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as a limitation on the present disclosure.

[0045] Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the technical features being referred to. Thus, a feature identified as "first," "second," or "third" may explicitly or implicitly include at least one of these features.

[0046] FIG1 is a schematic structural diagram of an embodiment of the main inclined shaft belt conveyor of the present invention.

[0047] As shown in Figure 1, the main inclined shaft belt conveyor can include a head unloading roller 1, a first head drive roller 2, a second head drive roller 3, a first redirecting roller 4, a second redirecting roller 5, an intermediate unloading roller 6, a first intermediate drive roller 8, a second intermediate drive roller 7, a third intermediate drive roller 9, a tail roller 10, a belt scale 11, and a tensioning device 12. The head drive unit, consisting of the first head drive roller 2 and the second head drive roller 3, can be located above ground, while the intermediate drive unit, consisting of the first intermediate drive roller 8, the second intermediate drive roller 7, and the third intermediate drive roller 9, can be located underground in a coal mine. This arrangement allows the distance between the head drive unit and the intermediate drive unit to be greater than 2,000 meters, making it suitable for applications in complex terrain and enabling long-distance transport. In this embodiment, this distance is approximately 2,100 meters. In other optional embodiments, those skilled in the art can adjust the distance between the head drive unit and the intermediate drive unit based on the actual working environment.

[0048] Specifically, a belt for conveying coal is wound around the head unloading drum 1, the middle unloading drum 6, and the tail drum 10. The head conveying section is formed between the head unloading drum 1 and the middle unloading drum 6, and the tail conveying section is formed between the middle unloading drum 6 and the tail drum 10.

[0049] Downstream of the intermediate unloading roller 6, the first intermediate drive roller 8, the second intermediate drive roller 7, and the third intermediate drive roller 9, which are located below the tail conveying section, are sequentially arranged. Downstream of the head unloading roller 1, the first redirecting roller 4, the first head drive roller 2, the second head drive roller 3, and the second redirecting roller 5, which are located below the head conveying section, are sequentially arranged. The first redirecting roller 4 and the second redirecting roller 5 are located below the head conveying section. Specifically, the first redirecting roller 4 is located downstream of the head unloading roller 1, the first head drive roller 2 is located downstream of the first redirecting roller 4, the second head drive roller 3 is located downstream of the first head drive roller 2, and the second redirecting roller 5 is located downstream of the second head drive roller 3.

[0050] In this embodiment, two motors are connected to each side of the first head drive roller 2 via shafts, the second head drive roller 3 is connected to a motor via shafts, and the first intermediate drive roller 8, the second intermediate drive roller 7, and the third intermediate drive roller 9 are each connected to a motor via shafts, for a total of six motors in the entire belt conveyor. Each motor is equipped with a frequency converter, and all six frequency converters have the same initial power. Furthermore, a 2:1 power distribution ratio is used for the first head drive roller 2 and the second head drive roller 3, while a 1:1:1 power distribution ratio is used for the first intermediate drive roller 8, the second intermediate drive roller 7, and the third intermediate drive roller 9. It should be noted that in this embodiment, the power distribution arrangement is implemented using frequency converters of equal power but different numbers. In alternative embodiments, those skilled in the art may implement the power distribution arrangement using other methods, and the specific power distribution ratio can also be set based on actual operational needs.

[0051] The bend rollers 4 and 5 are primarily used to change the conveyor belt's direction of travel. They also compress the conveyor belt, increasing its wrap angle with the drive rollers 2 and 3. Slippage between the conveyor belt and the drive rollers 2 and 3 can cause wear on the conveyor belt's rubber coating, which can in severe cases burn and even cause fires. Therefore, in this embodiment, two bend rollers 4 and 5 are installed near the drive rollers 2 and 3. The belt conveyor's conveying direction can be changed by changing the direction of the first bend roller 4 and the second bend roller 5, effectively preventing belt slippage.

[0052] In this embodiment, the belt conveyor may also have a control system. Specifically, the control system may include a head control main station, a mid-machine control substation, and a tail control substation. The head control main station, the mid-machine control substation, and the tail control substation implement control and signal acquisition through bus communication. Analog input and output modules are respectively provided in the head control main station, the mid-machine control substation, and the tail control substation. The analog input and output modules are used for data acquisition and control. The modules may include one or more analog input channels that can convert signals from sensors, such as the belt scale 11 and the tensioning device 12 in this embodiment, into digital signals and process them in the control system. Similarly, the analog output channels can convert digital signals into electrical signals from the control system, output controllable analog transmission currents, and transmit them to the frequency converter to control corresponding actuators, such as the tensioning device 12 or the motor.

[0053] In this embodiment, the three communicate via the ProfiBus bus, and respectively collect data from the belt scale 11 and the tensioning device 12. In other optional embodiments, those skilled in the art can select other buses for communication according to actual needs.

[0054] Specifically, in the embodiment shown in Figure 1, the analog input / output module of the locomotive tail control substation transmits real-time coal readings from a belt scale 11 located at the locomotive tail of the belt conveyor via a belt scale controller. The analog input / output module of the locomotive head control main station controls the tensioning device 12 located at the locomotive head of the belt conveyor via a tensioning device controller. In this embodiment, the belt scale 11 is an explosion-proof electronic belt scale. In alternative embodiments, those skilled in the art may adjust the specific deployment locations and models of the belt scale 11 and tensioning device 12 based on actual operating conditions.

[0055] In this embodiment, the six frequency converters are all located in the ground frequency converter room. The ground frequency converter room is about 2180 meters away from the intermediate unloading roller 6. The high-voltage frequency converter can provide long-distance power supply to the first head drive roller 2, the second head drive roller 3, the first intermediate drive roller 8, the second intermediate drive roller 7, and the third intermediate drive roller 9. The frequency converter in this embodiment uses Siemens Robincon, with an input voltage of 10kV and an output voltage of 6kV. In other optional embodiments, those skilled in the art can set the number of high-voltage frequency converters, select the model of the frequency converter, and adjust the distance between the ground frequency converter room and the intermediate unloading roller 6 according to actual work needs and environment.

[0056] In addition, the high-voltage inverter can also adjust the power balance of the six motors mentioned above. Specifically, each motor is regulated and controlled by a corresponding high-voltage inverter. The locomotive control master station adjusts the tension of the tensioning device 12 according to preset rules based on the coal load on the belt scale, the tension value of the tensioning device 12, and the current data of the motors at the first locomotive drive roller 2, the second locomotive drive roller 3, the first intermediate drive roller 8, the second intermediate drive roller 7, and the third intermediate drive roller 9. It also sends a speed reference compensation signal to the inverter with the largest current difference among the motors, minimizing the current difference between the inverters and achieving power balance among the motors. The specific preset rules and control methods are explained in detail below and will not be elaborated on here. The power balance between the motors can be adaptively controlled and can be maintained above 95% throughout the life cycle of the belt conveyor.

[0057] FIG2 is a flow chart of an embodiment of a power balance adaptive control method according to the present invention.

[0058] The 1#-6# inverters in the figure are the six inverters corresponding to the six motors mentioned above.

[0059] The present invention provides a power balance adaptive control method for a belt conveyor. The components of the belt conveyor and the connection relationship between the structures are described in detail in the embodiment of FIG1 and will not be described in detail here.

[0060] The power balance adaptive control method of the belt conveyor is the preset rule mentioned above, which can specifically include the following steps:

[0061] Step S1: the main head control station controls the motor frequency converters of the first head drive roller 2, the second head drive roller 3, the first intermediate drive roller 8, the second intermediate drive roller 7 and the third intermediate drive roller 9 according to a given standard speed;

[0062] Step S2: obtaining in real time the coal quantity of the belt scale 11, the tension value of the tensioning device 12, and the current value of the motor inverter;

[0063] Step S3: Using the average current value of the motor inverter as a reference current, the current value of each inverter is compared with the reference current, the inverter data with the worst power balance is saved, and it is determined whether the ratio exceeds the preset power balance. If so, the process proceeds to step S4; otherwise, step S3 is repeated.

[0064] Step S4: judging whether to adjust the belt tension according to the coal quantity measured by the belt scale 11 and the tensioning force of the tensioning device 12, if yes, proceeding to step S5, otherwise proceeding to step S6;

[0065] Step S5: the analog input / output module of the machine head control master station outputs an analog transmission current signal to the tensioning controller of the tensioning device 12 for tension adjustment;

[0066] Step S6: Perform speed setting compensation on the inverter with the worst power balance, and determine whether the power balance of the inverter with the worst power balance is better than the previous power balance. If yes, proceed to step S7; otherwise, proceed to step S9.

[0067] Step S7: Determine whether the power balance of the inverter with the worst power balance meets the balance requirement. If yes, complete the current adjustment; otherwise, proceed to step S8;

[0068] Step S8: Repeat step S6 until the power balance of the inverter with the worst power balance meets the power balance requirement or the power balance is worse than the previous data;

[0069] Step S9: the main control station of the locomotive controls the inverter with the worst power balance according to the given standard speed plus the compensation speed, and restores the previous adjustment.

[0070] In this embodiment, step S1 is executed at 100% of the standard speed, and the inverter performs power balancing according to its own "droop control" function. In other optional embodiments, those skilled in the art may set different preset values ​​for the preset power balance mentioned in step S3 according to different circumstances.

[0071] In this embodiment, the analog output current of the head control master station in step S5 is between 4 and 20 mA, and the corresponding current value is compensated based on the current value of the inverter with the worst power balance. In this embodiment, the analog output current range used is used to reduce errors caused by inverter power balance adjustment. In other optional embodiments, those skilled in the art may adjust the analog output current range according to actual needs.

[0072] In step S6, the speed compensation is calculated by the locomotive control master station by subtracting the compensation speed from the given standard speed and transmitting it to the inverter with the worst power balance, with a delay of 20 seconds. In this embodiment, the compensation speed is set to 0.1% of the standard speed. In other optional embodiments, those skilled in the art may select different percentages of the standard speed and different delay times for transmission according to different circumstances.

[0073] To sum up, the present invention coordinates the control and adjustment of the given speeds of multiple frequency converters through controllers such as a belt scale controller and a tensioning device controller and the tensioning device 12, so that the power balance of the belt conveyor reaches more than 95%. The long-distance power supply technology of the frequency converter is adopted throughout the entire life cycle of the belt conveyor, thereby improving the transportation capacity of the belt conveyor.

[0074] The technical scope of the present invention is not limited to the contents of the above description. Those skilled in the art can make various deformations and modifications to the above embodiments without departing from the technical concept of the present invention, and these deformations and modifications should all fall within the scope of the present invention.

Claims

1. A belt conveyor for a main inclined shaft of a mine, characterized in that: The belt conveyor comprises a head unloading roller (1), an intermediate unloading roller (6) and a tail roller (10), wherein belts for conveying are wound around the head unloading roller (1), the intermediate unloading roller (6) and the tail roller (10), a head conveying section is formed between the head unloading roller (1) and the intermediate unloading roller (6), a tail conveying section is formed between the intermediate unloading roller (6) and the tail roller (10), and a first intermediate driving roller (8), a second intermediate driving roller (7) and a third intermediate driving roller (9) are sequentially arranged downstream of the intermediate unloading roller (6) and located below the tail conveying section, and a first head driving roller (2) and a second head driving roller (3) are sequentially arranged downstream of the head unloading roller (1) and located below the head conveying section.

2. The belt conveyor according to claim 1, characterized in that: The first head drive roller (2) is located upstream of the second head drive roller (3), and the first head drive roller (2) and the second head drive roller (3) adopt a 2:1 power distribution arrangement, and the first intermediate drive roller (8), the second intermediate drive roller (7) and the third intermediate drive roller (9) adopt a 1:1:1 power distribution arrangement.

3. The belt conveyor according to claim 1, characterized in that: The belt conveyor has a control system, which includes a head control main station, a mid-machine control substation, and a tail control substation. The head control main station, the mid-machine control substation, and the tail control substation realize control and signal acquisition through bus communication.

4. The belt conveyor according to claim 3, characterized in that: The first head drive roller (2) and the second head drive roller (3) are located on the ground, the first intermediate drive roller (8), the second intermediate drive roller (7) and the third intermediate drive roller (9) are located underground in a coal mine, and a belt scale (11) is arranged at the tail of the belt conveyor, and the analog input and output module of the tail control substation reads the coal quantity on the belt scale from the belt scale (11) through the belt scale controller, and a tensioning device (12) is arranged at the head of the belt conveyor, and the analog input and output module of the head control main station reads the coal quantity on the belt scale from the belt scale (11) through the tensioning device The controller controls the tensioning device (12), and the locomotive control main station adjusts the tensioning force of the tensioning device (12) according to the coal quantity of the belt scale, the tension value of the tensioning device (12), the current data of the motors at the first locomotive drive roller (2), the second locomotive drive roller (3), the first intermediate drive roller (8), the second intermediate drive roller (7) and the third intermediate drive roller (9) according to a preset rule, and sends a speed setting compensation signal to the frequency converter with the largest current difference in the motor, so as to keep the power balance above 95%.

5. The belt conveyor according to claim 4, characterized in that: The preset rules are: Step S1: The head control main station controls the first head drive roller (2) according to a given standard speed. Motor frequency converters for the second head drive roller (3), the first intermediate drive roller (8), the second intermediate drive roller (7) and the third intermediate drive roller (9); Step S2: acquiring in real time the coal quantity of the belt scale (11), the tension value of the tensioning device (12) and the current value of the motor inverter; Step S3: taking the average current value of the motor inverter as the reference current, comparing the current value of each inverter with the reference current, saving the inverter data with the worst power balance, and judging whether the ratio exceeds the preset power balance, if yes, proceed to step S4, otherwise repeat step S3; Step S4: judging whether to adjust the belt tension according to the coal quantity of the belt scale (11) and the tensioning force of the tensioning device (12); if yes, proceed to step S5; otherwise, proceed to step S6; Step S5: the analog input / output module of the machine head control main station outputs an analog transmission current signal to the tensioning controller of the tensioning device (12) for tension adjustment; Step S6: Perform speed setting compensation on the inverter with the worst power balance, and determine whether the power balance of the inverter with the worst power balance is better than the previous power balance. If yes, proceed to step S7; otherwise, proceed to step S9; Step S7: judging whether the power balance of the inverter with the worst power balance meets the balance requirement, if yes, completing the current adjustment, otherwise proceeding to step S8; Step S8: Repeat step S6 until the power balance of the inverter with the worst power balance meets the power balance requirement or the power balance is worse than the previous data; Step S9: the head control master station controls the inverter with the worst power balance according to the given standard speed plus the compensation speed, and restores the previous adjustment.

6. The belt conveyor according to claim 5, characterized in that: In step S6, the speed setting compensation is performed by the head control master station to control the inverter with the worst power balance according to the given standard speed minus the compensation speed, with a delay of 20 seconds.

7. A power balance adaptive control method for a belt conveyor, characterized in that: The belt conveyor comprises a head unloading roller (1), an intermediate unloading roller (6) and a tail roller (10), on which a belt for conveying is wound, a head conveying section is formed between the head unloading roller (1) and the intermediate unloading roller (6), and a tail conveying section is formed between the intermediate unloading roller (6) and the tail roller (10), and a first intermediate driving roller (8), a second intermediate driving roller (7) and a third intermediate driving roller (9) are sequentially arranged at the downstream of the intermediate unloading roller (6) and located below the tail conveying section, a first head driving roller (2) and a second head driving roller (3) are sequentially arranged at the downstream of the head unloading roller (1) and located below the head conveying section, the first head driving roller (2) being located upstream of the second head driving roller (3), a belt scale (11) being arranged at the tail of the belt conveyor, and a tensioning device (12) being arranged at the head of the belt conveyor, In addition, the belt conveyor has a control system, which includes a head control main station, a mid-machine control substation, and a tail control substation. The head control main station, the mid-machine control substation, and the tail control substation communicate to realize control and signal acquisition. The analog input and output module of the tail control substation reads the coal quantity on the belt scale (11) from the belt scale controller. The analog input and output module of the head control main station controls the tensioning device (12) through the tensioning device controller. Wherein, the method comprises the following steps: Step S1: the head control main station controls the motor frequency converters of the first head drive roller (2), the second head drive roller (3), the first intermediate drive roller (8), the second intermediate drive roller (7) and the third intermediate drive roller (9) according to a given standard speed; Step S2: obtaining in real time the coal weighing amount of the belt of the belt scale (11), the tension value of the tensioning device (12) and the current value of the motor inverter; Step S3: taking the average current value of the motor inverter as the reference current, comparing the current value of each inverter with the reference current, saving the inverter data with the worst power balance, and judging whether the ratio exceeds the preset power balance, if yes, proceed to step S4, otherwise repeat step S3; Step S4: judging whether to adjust the belt tension according to the coal quantity of the belt scale (11) and the tension value of the tensioning device (12); if yes, proceed to step S5; otherwise, proceed to step S6; Step S5: the analog output of the machine head control main station is a 4-20 mA current signal to the tension controller of the tensioning device (12) for tension adjustment; Step S6: Perform speed setting compensation on the inverter with the worst power balance, and determine whether the power balance of the inverter with the worst power balance is better than the previous power balance. If yes, proceed to step S7; otherwise, proceed to step S9; Step S7: judging whether the power balance of the inverter with the worst power balance meets the balance requirement, if yes, completing the current adjustment, otherwise proceeding to step S8; Step S8: Repeat step S6 until the power balance of the inverter with the worst power balance meets the power balance requirement. The balance requirement or power balance is worse than the previous data; Step S9: the head control master station controls the inverter with the worst power balance according to the given standard speed plus the compensation speed, and restores the previous adjustment.

8. The method according to claim 7, characterized in that In step S6, the speed setting compensation is performed by the head control master station to control the inverter with the worst power balance according to the given standard speed minus the compensation speed, with a delay of 20 seconds.

9. The method according to claim 7, characterized in that The first head drive roller (2) is located upstream of the second head drive roller (3), and the first head drive roller (2) and the second head drive roller (3) adopt a 2:1 power distribution arrangement, and the first intermediate drive roller (8), the second intermediate drive roller (7) and the third intermediate drive roller (9) adopt a 1:1:1 power distribution arrangement.

10. The method according to claim 9, characterized in that The locomotive control main station adjusts the tension value of the tension device (12) according to the coal quantity on the belt scale, the tension value of the tension device (12), the current data of the motors at the first locomotive drive roller (2), the second locomotive drive roller (3), the first intermediate drive roller (8), the second intermediate drive roller (7) and the third intermediate drive roller (9) according to a preset rule, and sends a speed setting compensation signal to the frequency converter with the largest current difference among the motors, and keeps the power balance above 95%.

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