System for driving large mills with double variable frequency synchronous motors

Abstract

The application relates to the field of electric machines, and provides a system for driving a large-scale grinding machine by using a double-frequency synchronous motor, which comprises a main frequency converter control module, a slave frequency converter control module and a gear transmission mechanism; a first input end of the main frequency converter control module is connected with a power supply; an output end of the main frequency converter control module is connected with a first input end of the gear transmission mechanism; a first input end of the slave frequency converter control module is connected with the power supply; an output end of the slave frequency converter control module is connected with the first input end of the gear transmission mechanism; an output end of the gear transmission mechanism is connected with the grinding machine and used for driving the grinding machine; the main frequency converter control module comprises a main frequency converter; and the slave frequency converter control module comprises a slave frequency converter. The system can solve the defects that, in the prior art, when a high-power motor is started, not only is there a strong impact on the power grid, but also the abrasion of mechanical equipment is aggravated; the system drives the large-scale grinding machine by using the double-frequency synchronous motor, so that the product capacity is higher, safer and more stable.

Description

Technical Field

[0001] This invention relates to the field of motor technology, and in particular to a system for driving a large mill using a dual-frequency synchronous motor. Background Technology

[0002] The mill is one of the core components determining a mine's production capacity. Generally speaking, the larger the mill, the more ore it can grind in a single pass, and the higher the overall plant's capacity. However, as the mill grows larger, it experiences greater impact during the ore grinding process. This impact is transmitted to the gear transmission mechanism, making its design and manufacture extremely difficult. Furthermore, as the mill acts as a load, the larger the mill, the larger the required drive equipment (i.e., the motor). Larger motors are more difficult to manufacture and transport. Moreover, with larger motors, conventional motors generate extremely large inrush currents during startup, which not only have a strong impact on the power grid but also accelerate the wear and tear on the mechanical equipment. Summary of the Invention

[0003] This invention provides a system for driving a large mill with a dual-frequency synchronous motor, which solves the problem in related technologies where high-power motors generate a large inrush current during startup, which not only has a strong impact on the power grid but also exacerbates the wear and tear on mechanical equipment. The solution of this application uses a dual-frequency synchronous motor to drive a large mill, which requires less installation space, is relatively simple to design and manufacture, saves costs, is easy to maintain in the later stage, and makes the product have higher production capacity and is safer and more stable.

[0004] This invention provides a system for driving a large mill using a dual-frequency synchronous motor, comprising: Main frequency converter control module, slave frequency converter control module, and gear transmission mechanism; The first input terminal of the main frequency converter control module is connected to the power supply, and the output terminal of the main frequency converter control module is connected to the first input terminal of the gear transmission mechanism. The first input terminal of the slave frequency converter control module is connected to the power supply, and the output terminal of the slave frequency converter control module is connected to the first input terminal of the gear transmission mechanism. The output end of the gear transmission mechanism is connected to the mill and is used to drive the mill; The main inverter control module includes a main inverter, and the slave inverter control module includes a slave inverter. The main inverter is used to connect to the slave inverter via optical fiber and control the slave inverter.

[0005] The system for driving a large mill with a dual-frequency synchronous motor according to the present invention further includes a motor control module, which is connected to the main frequency converter control module and the slave frequency converter control module. The motor control module includes: A main frequency converter auxiliary unit is connected to the main frequency converter. The auxiliary frequency converter unit is connected to the slave frequency converter. Excitation unit.

[0006] According to the system for driving a large mill with a dual-frequency synchronous motor provided by the present invention, the excitation unit includes a first excitation unit and a second excitation unit; The main frequency converter control module includes a No. 1 motor, and the No. 1 excitation unit is connected to the No. 1 motor and is used to provide excitation current to the No. 1 motor; The secondary frequency converter control module includes a second motor, and the second excitation unit is connected to the second motor to provide excitation current to the second motor.

[0007] According to the system for driving a large mill with a dual-frequency synchronous motor provided by the present invention, the No. 1 motor is connected to the main frequency converter through a No. 1 motor speed encoder. The No. 1 motor speed encoder is used to collect the operating parameters of the No. 1 motor and send them to the main frequency converter. The second motor is connected to the slave frequency converter via a second motor speed encoder. The second motor speed encoder is used to collect the operating parameters of the second motor and send them to the slave frequency converter.

[0008] According to the system for driving a large mill with a dual-frequency synchronous motor provided by the present invention, the motor control module further includes: A No. 1 motor auxiliary unit is connected to the No. 1 motor; The No. 2 motor auxiliary unit is connected to the No. 2 motor.

[0009] According to the system for driving a large mill with a dual-frequency synchronous motor provided by the present invention, the first excitation unit includes a first excitation device and a first motor exciter. The first excitation device is used to drive the exciter of the first motor to generate excitation current under the control of the motor control module; The exciter for motor No. 1 is connected to motor No. 1 and is used to provide excitation current to motor No. 1. The second excitation unit includes a second excitation device and a second motor exciter. The second excitation device is used to drive the second motor exciter to generate excitation current under the control of the motor control module. The exciter for the second motor is connected to the second motor and is used to provide excitation current to the second motor.

[0010] The system for driving a large mill with a dual-frequency synchronous motor according to the present invention also includes an operation box; The control box is connected to the motor control module, the main frequency converter, and the slave frequency converter; The control box is used to receive operation commands and drive the motor control module, and / or the main frequency converter, and / or the slave frequency converter.

[0011] This application's solution employs a parallel drive system with dual variable frequency synchronous motors. Two frequency converters drive a large mill load, reducing the stress on one side of the gear transmission structure. The master-slave frequency converter control system improves control accuracy, balances the output of the two motors, and prevents overheating of a single motor. With the dual drive system, the power supplied to the mill by the two motors is doubled. Further optimization of the gear mechanism can increase the total output power even more. The dual-motor drive system requires synchronicity between the two motors, necessitating a master-slave control mode to drive both motors to run or stop simultaneously. Moreover, the frequency converter control allows for speed adjustment based on ore characteristics, maximizing equipment utilization. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram of the structure of a system for driving a large mill with a dual-frequency synchronous motor, provided in an embodiment of the present invention.

[0014] in: 1-Grinding mill; 2-Gear transmission mechanism; 3-Motor No. 1; 4-Control box; 5 - Excitation device No. 1; 6 - AC380V power supply; 7 - Exciter No. 1 motor; 8 - Speed ​​encoder for motor No. 1; 9 - Auxiliary unit for motor No. 1; 10-Main frequency converter auxiliary unit; 11-Main frequency converter; 12-Motor control cabinet; 13 - Speed ​​encoder for motor No. 2; 14 - Exciter for motor No. 2; 15 - Motor No. 2; 16 - Excitation device for motor No. 2; 17 - Auxiliary unit for motor No. 2; 18 - AC10kV power supply; 19 - Slave inverter auxiliary unit; 20 - Slave inverter; 21 - Fiber optic cable; 22 - Incoming cabinet from frequency converter; 23 - Incoming cabinet from main frequency converter. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0016] Figure 1 This is a schematic diagram of the structure of a system for driving a large mill with a dual-frequency synchronous motor, provided in an embodiment of the present invention.

[0017] like Figure 1 As shown, this embodiment provides a system for driving a large mill using dual-frequency synchronous motors, including: Main frequency converter control module, slave frequency converter control module, and gear transmission mechanism; The first input terminal of the main frequency converter control module is connected to the power supply, and the output terminal of the main frequency converter control module is connected to the first input terminal of the gear transmission mechanism. The first input terminal of the slave frequency converter control module is connected to the power supply, and the output terminal of the slave frequency converter control module is connected to the first input terminal of the gear transmission mechanism. The output end of the gear transmission mechanism is connected to the mill and is used to drive the mill; The main inverter control module includes a main inverter, and the slave inverter control module includes a slave inverter. The main inverter is used to connect to the slave inverter via optical fiber and control the slave inverter.

[0018] In an exemplary embodiment, the system further includes a motor control module, which is connected to the main inverter control module and the slave inverter control module. The motor control module includes: A main frequency converter auxiliary unit is connected to the main frequency converter. The auxiliary frequency converter unit is connected to the slave frequency converter. Excitation unit.

[0019] In an exemplary embodiment, the excitation unit includes a first excitation unit and a second excitation unit; The main frequency converter control module includes a No. 1 motor, and the No. 1 excitation unit is connected to the No. 1 motor and is used to provide excitation current to the No. 1 motor; The secondary frequency converter control module includes a second motor, and the second excitation unit is connected to the second motor to provide excitation current to the second motor.

[0020] In an exemplary embodiment, the No. 1 motor is connected to the main frequency converter via a No. 1 motor speed encoder. The No. 1 motor speed encoder is used to collect the operating parameters of the No. 1 motor and send them to the main frequency converter. The second motor is connected to the slave frequency converter via a second motor speed encoder. The second motor speed encoder is used to collect the operating parameters of the second motor and send them to the slave frequency converter.

[0021] In an exemplary embodiment, the motor control module further includes: A No. 1 motor auxiliary unit is connected to the No. 1 motor; The No. 2 motor auxiliary unit is connected to the No. 2 motor.

[0022] In an exemplary embodiment, the first excitation unit includes a first excitation device and a first motor exciter; The first excitation device is used to drive the exciter of the first motor to generate excitation current under the control of the motor control module; The exciter for motor No. 1 is connected to motor No. 1 and is used to provide excitation current to motor No. 1. The second excitation unit includes a second excitation device and a second motor exciter. The second excitation device is used to drive the second motor exciter to generate excitation current under the control of the motor control module. The exciter for the second motor is connected to the second motor and is used to provide excitation current to the second motor.

[0023] In an exemplary embodiment, an operation box is also included; The control box is connected to the motor control module, the main frequency converter, and the slave frequency converter; The control box is used to receive operation commands and drive the motor control module, and / or the main frequency converter, and / or the slave frequency converter.

[0024] like Figure 1As shown, in a specific embodiment, AC 10kV power supply 18 can be used to power the main inverter incoming cabinet 23 and the slave inverter incoming cabinet 22. The main inverter incoming cabinet 23 powers the main inverter 11, and the slave inverter incoming cabinet 22 powers the slave inverter 20. The main inverter 11 controls the slave inverter 20 through optical fiber 21. The speed encoder 8 of motor 1 uploads the speed and position parameters of motor 3 to the main inverter 11. The main inverter 11 controls motor 3 and supplies it with power. The speed encoder 13 of motor 2 uploads the speed and position parameters of motor 15 to the slave inverter 20. The slave inverter 20 controls motor 15 and supplies it with power. Motor 3 is connected to gear transmission mechanism 2, motor 15 is connected to gear transmission mechanism 2, and gear transmission mechanism 2 is connected to mill 1.

[0025] AC380V power supply 6 supplies power to motor control cabinet 12. Motor control cabinet 12 controls and supplies power to excitation device 5. Main frequency converter 11 controls excitation device 5. Excitation device 5 supplies power to motor exciter 7. Motor exciter 7 provides excitation to motor 3. Motor control cabinet 12 controls and supplies power to second excitation device 16. Slave frequency converter 20 controls second excitation device 16. Second excitation device 16 supplies power to motor exciter 14. Motor exciter 14 provides excitation to motor 15. AC380V power supply 6 supplies power to motor control cabinet 12. Motor control cabinet 12 controls and supplies power to auxiliary unit 9 of motor 1. Auxiliary unit 9 of motor 1 provides necessary auxiliary functions to motor 3, including cooling, lubrication, and moisture protection. Motor control cabinet 12 controls and supplies power to auxiliary unit 17 of motor 2. Auxiliary unit 17 of motor 2 provides necessary auxiliary functions to motor 15, including cooling, lubrication, and moisture protection. AC380V power supply 6 supplies power to motor control cabinet 12. Motor control cabinet 12 controls and supplies power to main frequency converter auxiliary unit 10. Main frequency converter auxiliary unit 10 provides necessary auxiliary functions, including cooling, to main frequency converter 11. Motor control cabinet 12 controls and supplies power to slave frequency converter auxiliary unit 19. Slave frequency converter auxiliary unit 19 provides necessary auxiliary functions, including cooling, to slave frequency converter 20. The control box 4 is connected to the motor control cabinet 12, the main frequency converter 11, and the slave frequency converter 20, so as to realize the function of controlling the above components on site.

[0026] The system for driving a large mill with a dual-frequency synchronous motor provided in this application has the following advantages: Large gear transmission mechanisms are complex to manufacture and costly. Conventional gear transmission mills can only achieve a power output of 10,000 kW. With the adoption of a dual drive system, two motors are connected to the gear drive system respectively, and the power on the mill side reaches twice that of the original, greatly improving the utilization efficiency.

[0027] By adopting a variable frequency dual-drive system, the system selects the most efficient rotational speed based on the grinding characteristics of the mined ore, operating within a speed range of 70-110%, thus maximizing equipment efficiency. Simultaneously, the variable frequency system provides a soft-start function, ensuring a smooth start-up process without mechanical vibration, reducing system impact and wear.

[0028] The use of a master-slave frequency converter control mode can effectively improve the accuracy of motor torque output and ensure the stable operation of the dual-motor system. Simultaneously, based on feedback from detection data, the system can assess the material caking situation inside the mill and remove the caking, preventing major accidents.

[0029] The drive system is highly intelligent. The entire drive system collects information through various monitoring components, enabling online automatic diagnosis, timely and reliable prediction of problems, and maximum automatic processing.

[0030] This invention reduces the design complexity of components such as gear transmission mechanisms, minimizes the space required for the overall equipment, increases factory capacity, reduces transportation costs for components such as motors, and lowers the cost of custom-made parts for frequency converters and motors. The successful use of master-slave frequency converters effectively improves the control precision of the two motors, balances their output, and the brushless frequency converter system architecture reduces toner generation, making it environmentally friendly. This invention provides a new solution for factories to increase capacity, increase investment, and achieve environmental protection.

[0031] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0032] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., including several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods of various embodiments or some parts of embodiments.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A system for driving a large mill using dual-frequency synchronous motors, characterized in that, include: Main frequency converter control module, slave frequency converter control module, and gear transmission mechanism; The first input terminal of the main frequency converter control module is connected to the power supply, and the output terminal of the main frequency converter control module is connected to the first input terminal of the gear transmission mechanism. The first input terminal of the slave frequency converter control module is connected to the power supply, and the output terminal of the slave frequency converter control module is connected to the first input terminal of the gear transmission mechanism. The output end of the gear transmission mechanism is connected to the mill and is used to drive the mill; The main inverter control module includes a main inverter, and the slave inverter control module includes a slave inverter. The main inverter is used to connect to the slave inverter via optical fiber and control the slave inverter.

2. The system for driving a large mill with a dual-frequency synchronous motor according to claim 1, characterized in that, It also includes a motor control module, which is connected to the main inverter control module and the slave inverter control module; The motor control module includes: A main frequency converter auxiliary unit is connected to the main frequency converter. The auxiliary frequency converter unit is connected to the slave frequency converter. Excitation unit.

3. The system for driving a large mill with a dual-frequency synchronous motor according to claim 2, characterized in that, The excitation unit includes a first excitation unit and a second excitation unit; The main frequency converter control module includes a No. 1 motor, and the No. 1 excitation unit is connected to the No. 1 motor and is used to provide excitation current to the No. 1 motor; The secondary frequency converter control module includes a second motor, and the second excitation unit is connected to the second motor to provide excitation current to the second motor.

4. The system for driving a large mill with a dual-frequency synchronous motor according to claim 3, characterized in that, The No. 1 motor is connected to the main frequency converter via a No. 1 motor speed encoder. The No. 1 motor speed encoder is used to collect the operating parameters of the No. 1 motor and send them to the main frequency converter. The second motor is connected to the slave frequency converter via a second motor speed encoder. The second motor speed encoder is used to collect the operating parameters of the second motor and send them to the slave frequency converter.

5. The system for driving a large mill with a dual-frequency synchronous motor according to claim 1, characterized in that, The motor control module also includes: A No. 1 motor auxiliary unit is connected to the No. 1 motor; The No. 2 motor auxiliary unit is connected to the No. 2 motor.

6. The system for driving a large mill with a dual-frequency synchronous motor according to claim 3, characterized in that, The first excitation unit includes a first excitation device and a first motor exciter; The first excitation device is used to drive the exciter of the first motor to generate excitation current under the control of the motor control module; The exciter for motor No. 1 is connected to motor No. 1 and is used to provide excitation current to motor No.

1. The second excitation unit includes a second excitation device and a second motor exciter. The second excitation device is used to drive the second motor exciter to generate excitation current under the control of the motor control module. The exciter for the second motor is connected to the second motor and is used to provide excitation current to the second motor.

7. The system for driving a large mill with a dual-frequency synchronous motor according to claim 2, characterized in that, It also includes the control box; The control box is connected to the motor control module, the main frequency converter, and the slave frequency converter; The control box is used to receive operation commands and drive the motor control module, and / or the main frequency converter, and / or the slave frequency converter.

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