Constant voltage frequency ratio control system and constant voltage frequency ratio control method of multi-motor driving belt conveyor

Abstract

The invention discloses a constant voltage frequency ratio control system of a multi-motor driving belt conveyor, wherein each motor is controlled through an independent frequency converter, a primary frequency converter and each secondary frequency converter are connected through a communication line, and each frequency converter can detect active current. Startup procedures of a constant voltage frequency ratio control method of the multi-motor driving belt conveyor include multiple steps, wherein a step a is that startup signals are received and broadcasted; a step b is that the multi-motor driving belt conveyor is started in a constant voltage frequency ratio control mode; a step c is that the secondary frequency converters are in operation; a step d is that whether the active current is in an allowed range is detected; and a step e is that frequency of each secondary frequency converter is adjusted. Operation procedures of the constant voltage frequency ratio control method of the multi-motor driving belt conveyor include multiple steps, wherein a step g is that operation frequency and the active current are broadcasted; a step h is that the active current is judged; and a step i is that the frequency is adjusted. Shutdown procedures of the constant voltage frequency ratio control method of the multi-motor driving belt conveyor include multiple steps, wherein a step j is that shutdown signals are received and broadcasted, and a step k is that the multi-motor driving belt conveyor is stopped in the constant voltage frequency ratio control mode. Through the constant voltage frequency ratio control system and the constant voltage frequency ratio control method of the multi-motor driving belt conveyor, all the motors basically have the same output torque, and therefore the problem that the motors are at the same rotating speed but have different output torque due to the facts that rotary drums are different in size and the sizes of belt wrap angles are not constant is solved, and the multi-motor driving belt conveyor is enabled to be started and stopped stably and can operate with high efficiency.

Description

technical field [0001] The present invention relates to a constant voltage-frequency ratio control system and method for a multi-motor-driven belt conveyor, and more specifically, to a multi-motor-driven belt conveyor that can effectively ensure that the output power of each motor is basically the same. Constant voltage frequency ratio control system and method. Background technique [0002] Most of the existing belt conveyors in China are driven by power frequency, and frequency converter is rarely used. Due to the long-term power frequency operation of the motor and the efficiency of the hydraulic coupling, the belt conveyor consumes high energy consumption and is very uneconomical; at the same time, because the motor cannot use soft start and soft stop, it will produce severe impact on the machine and accelerate the wear of the machine There are also problems such as wear and maintenance of belts and hydraulic couplings that will bring a large amount of expense to the e...

AI Technical Summary

Problems solved by technology

[0004] In the process of starting the multi-motor drag belt conveyor, if the control is not proper, the output torque of the motors will be different, and even some motors will be in the electric state, while some motors will be in the power generation state.

For the inverter, this situation is fatal. When the motor is in the power generation state, it will charge the capacitor through the freewheeling diode of the IGBT. Since the front end of the capacitor is rectified by a diode, the energy flow is irreversible, and the voltage of the capacitor will become higher and higher. , until the unit overvoltage protection

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