Research Of Network Control Of Inverter

With the control technology of the industrial field increasing development, the frequency converter motor has become the main way of the motor speed regulation. At present, many kinds of inverters have serial communication function. So compared with the traditonal terminal control, they have more capacity of resisting disturbance, more quickly transmission rate. And they can be more convenient to achieve a upper monitor controller for the Multiple inverter parameters control.Firstly, this paper introduces basic communication model and method of network control. A detailed analysis of the principle and application characteristics of the two standard interface RS-232and RS-422A/485which belongs to the serial communication interface was carried out. Then, Bus-Frequency conversion control system was studied and designed. including ProfiBus and the variable frequency control system of coal handling system based on ProfiBus, CC-Link bus and the variable frequency control system of blending tank system based on CC-Link, DeviceNet bus and the variable frequency control system of frequency constand pressure water supply system based on DeviceNet, and bus bridge comined by ProfiBus and MODBUS and the design of inverter group based on it.After that, comining with the field bus technology and different kinds of PLC, this paper puts forward the variable frequency control system. The design mainly includes the liquid level control system and draw winder system consist of inverter and Siemens PLC, speed winding head system consist of inverter and Mirco PLC, edge milling machine system consist of inverter and Delta PLC, new moving arm crane control system consist of inverter and OMRON PLC.In the last part, this paper introduces the Virtual instrument and LabVIEW software. Based on the practical project "500KW/1140V Three-Level Inverter", the paper writes programs composed of program receiving and displaying datas from lower system and control commands from the upper system. It cotains communication program, procedure of program, and notes in programming. LabVIEW has rich instruments and hardware driver of bus interface, which makes the LabVIEW can be used in many fields, increases readability, maintainability and clarity of the program.