Application Of Frequency Converters In The Rolling Control System

In our country, single stand four rollers reversible strip rolling mills still hold an important position in the cold-rolled strip manufactory industry. The DC driver system has been of the first place in speed control system, because of its excellent speed regulation performance, simplicity, easy operation, higher over-load and shock-load capability. With the development of electronic and computer technology, AC variable frequency inverters for AC motor speed control are widely used in various industry fields. In the 21st century, AC speed control technology is still a hot topic in the research field and has continuously been developed in depth.To the reconstruction project specifically for rolling mills in one strip steel company, the programmable controller and inverter are applied to the control system of rolling mills and carried on deeper research in relevant respects. SIMOVERT MASTERDRIVES of Siemens inverter, which has the function of closed-loop speed control/torque control and can solve the rotation rate and torque regulation, is adopted in the system. S7-200 PLC of Siemens is used to collect data from fields, arithmetic and control equipments such as inverter and motor. Siemens programming software STEP 7 is used to design programs. Configuration software Pro tool/Pro is used to develop the friendly man-machine interface and to download into the industry touching screen. Staff members can set parameters of inverter, start or stop motor by using it.The following researches are respectively carried out:1. It clearly expounds the basic principle and method of the permanent tension control according to the characteristic of strip steel rolling system;2. It elaborates the structure of SIMOVERT MASTERDRIVES, basic principle and the advantage of inverter for speed adjustment;3. It states the fundamental structure and principle of PLC and the Siemens S7-200 PLC in detail;4. The structure, the configuration of hardware , the implement of software and the adopted anti-interference method are also introduced in this paper.