Belt conveyor is the main equipment to ensure the high yield and high efficiency of modern coal mine. The successful application of FGI FD2000 medium-voltage three-level inverter in coal mine belt machine reflects its excellent vector control and master-slave synchronous control characteristics, marking the further improvement of FGI frequency conversion innovation ability, and provides valuable practical experience for the green energy saving and environmental protection transformation in the mine field.
1.Introduction
The traditional belt conveyor adopts the power frequency operation mode, due to the long-term power frequency operation of the motor, coupled with the efficiency of the hydraulic coupler and other problems, the operation of the belt conveyor is very uneconomical; At the same time, because the motor can not use soft start and soft stop, it has a severe impact on the machinery and accelerates the wear of the machinery. There are belt, hydraulic coupler wear and maintenance problems will bring a large amount of cost problems to the enterprise.
2.Scheme design and description
Take two 1140V/315KW motor-driven belt conveyors in a coal mine in Guizhou as an example. In the case of power frequency operation, there is power imbalance between two motors, current overload phenomenon is frequent, and the life of the motor is jeopardized.
In the multi-motor drive system of belt conveyor, the key problems are speed synchronization and torque balance of each motor. In the application process, it is necessary to consider the situation of full load start-up, first of all, it is necessary to consider the selection of heavy-duty vector frequency converter, multi-machine synchronization and require the frequency converter to have excellent master-slave control function, so the FGI FD2000 medium-voltage three-level vector frequency converter is selected. This series of frequency conversion has the following outstanding performance:
◆ Starting torque: 0.5Hz/150% (SVC); 0 Hz/200% (VC)
◆ Overload capacity: 150% rated current 60s; 180% rated current 10s
◆ Three-level topology circuit, small du/dt, reduce the damage to the motor insulation
◆ CAN master-slave communication, high control accuracy, power balance < 3%
◆ Frequency setting mode: digital setting, analog setting, high-speed pulse, multi-speed setting, UP/DOWN terminal setting, Modbus remote communication setting, Profibus communication setting, master-slave mode setting, hierarchical multi-speed setting.
For 315KW dual-drive belt conveyor, fully considering its starting and running torque requirements, you can enlarge a certain gear to select a frequency converter, the optional model is FGI FD2000-60F-400G-12. Two motors on site drive the belt pulling coal through two rollers, so two frequency converters of the same power are selected, and the synchronization between the frequency converters is realized through the master-slave control mode. In view of the fact that the load connection of the belt conveyor is through a flexible connection, there is a certain ductility, and there can be a certain speed error between the master and slave machines, so the main machine adopts the speed, and the slave machine can adopt the torque mode.
4.Application performance
FGI FD2000 General frequency converter for mining
The belt conveyor driven by FD2000 frequency inverter operates well, and embodies the following advantages:
◆ Speed synchronization, current balance. Slave torque is consistent with the main engine. The current difference is within 5A. The slave machine does not appear to match the speed of the main machine, resulting in overvoltage phenomenon.
◆ Simple parameters. Fewer parameters need to be set and adjusted, low sensitivity to motor parameters, very suitable for one master multi-slave application scenarios.
◆ Excellent soft start/stop feature. Acceleration/deceleration time (0-60min) is continuously adjustable, and can achieve S-type acceleration and deceleration, effectively reducing start-stop impact.
◆ Heavy load starts smoothly. The belt conveyor stops and restarts at any time in the coal transport process without problems, and the maximum output of 1.5 times rated torque can be produced at low frequency operation.
5.Summarize
FD2000 special movement for mining inverter
FGI FD2000 frequency inverter, as the power driving equipment of coal mine belt conveyor, has a broad application prospect in coal production for its advantages of high efficiency, low noise, large starting torque, high reliability, good speed regulation performance, maintenance-free and so on.