1.Overview

DQ Mine of Tonghua Coal Industry Company was founded in 1987, located in the west of Baishan City, at the foot of Changbai Mountain, beside the Hunjiang River, adjacent to Tonghua City, adjacent to "Chuan" expressway and North-South railway; By the end of 2006, the proven mineral resources reserves of the mine were 45.804 million tons, and the annual mining capacity was 750,000 tons.

Related parameters of daoqing coal mine belt: one-way belt length 1200m, belt width 1.2m. The maximum speed of the belt of the motor is 2 m/s. The mine tilt Angle is 25 degrees. Two motors operate at the same time, and the nameplate parameters of the two motors are the same.

2.Implementation plans

Two sets of FD5000-6/450F high-voltage inverter, which are manufactured by FGI, have a nominal voltage of 6 kV, a rated current of 54A and a rated power of 450 kW. Using "one tow and one" master control scheme, the main circuit control line is illustrated in Figure 1.

Figure 1 Wiring diagram for one drag one control once

In the double belt conveyor variable frequency speed control system, the high voltage inverter is selected as the master-slave control mode, which can make the motor achieve efficient load balance. Two 450 kW frequency converters are used on site to control two 400 kW high voltage motors. The 1# frequency converters are selected to communicate with the master frequency converters through ModBus to detect the working current of the 1# and 2# motors and give a given value of output torque. The 2# motors are controlled by the frequency converters. Thus, the synchronous operation of the 2# motor is realized.

The master high voltage frequency conversion control system and the secondary control system have external signal chain control and status, alarm logic signal output, the main control system receives the local or remote "start", "stop" and "emergency stop" instruction and "emergency stop" instruction from the slave control high voltage frequency conversion control system, receives the "start" and "emergency stop" instruction from the master control high voltage frequency conversion control system, and receives the "emergency stop" instruction from the secondary voltage frequency control system. Logic interlocking is performed in the PLC logic program of the two high voltage frequency conversion speed control systems, so that the two high voltage frequency conversion speed control systems can start and stop at the same time.

3.Application advantage

(1) Using FD5000 high voltage frequency inverter can achieve the soft start of the belt machine. The motor starts the belt conveyor slowly, slowly releases the energy stored inside the tape, can minimize the impact caused by the start and stop of the conveyor, and almost causes no damage to the tape.

(2) Using FD5000 high voltage frequency inverter can reduce the strength of the tape belt. Since the start time of frequency inverter can be adjusted within 1~3600s, the start time of belt conveyor is usually set within 60~200s according to the field situation. The extended start time greatly reduces the requirement of belt strength and reduces the initial investment of equipment. In practical application, due to the reduction of the starting impact, the loss of the mechanical system is also reduced, especially the life of the roller and the roller is greatly extended.

(3)The FD5000 high voltage frequency inverter is used to achieve the torque balance of the belt conveyor when driven by multiple motor. The frequency converter can be used to drive the belt conveyor, and the main-slave or coordination cabinet control mode can be used to realize the torque balance.

(4) Belt inspection function. Low-speed belt inspection function is the requirement of belt conveyor maintenance. The variable frequency speed regulation system is an AC transmission system without pole speed regulation, which can adjust any band speed within 0~100% rated band speed in the state of no-load band test.

(5) Smooth reload start. The low frequency converter can output 2.2 times the rated torque, which is suitable for heavy load start.

(6) FD5000 high voltage frequency inverter can automatically speed.The frequency converter and the coal flow sensor can automatically adjust the speed of the tape according to the weight of the load, which also reduces the wear of the tape.

(7) Energy saving with FD5000 high voltage inverter. . Corresponding to the special production conditions of coal mine, sometimes, coal production is extremely uneven, of course, the belt conveyor system of coal quantity is uneven, in light load or no load, the high speed operation of the belt conveyor system to mechanical transmission system wear waste is more serious, and the power consumption is low speed operation, but the production of the belt conveyor system cannot stop at any time, using a separate control system of the advanced transportation system load, the transportation system load measurement, which can control the inverter speed or speed in advance. For the belt conveyor system with uneven load, it can save electricity and reduce the belt wear.