Application of “one variable multi control” system in large highvoltage coal mill
                                                             ZHANG Bingyi, LIU Siqiang, FENG Guihong
                      （School of Electrical Engineering, Shenyang University of Technology, Shenyang 110870, China）

Abstract: Aiming at the problem of “one to one” control mode of permanent magnet direct drive system can not make the overall energy saving effect of the system achieve the best ,the problems in the combination of permanent magnet direct drive motor and “one variable multi control” control system were studied. The design method of permanent magnet direct drive motor for large highvoltage coal mill and the design method of “one variable multi control” control system were described. In the permanent magnet direct drive motor design, the permanent magnet direct drive motor model based on Matlab program combined with Ansoft finite element analysis method was established, the steadystate characteristics was analyzed. In the design of “one variable multi control” control system, on the basis of the existing “maximum torque current ratio” control mode, the switching loop was added, and an effective control process was put forward. The prototype was made to verify the experiment. The research results show that in the “one variable multi control” system, the steadystate parameters of permanent magnet direct drive motor can meet users needs. The control system of “one variable multi control” system has no impact on the current and voltage during the handover process.

Key words: coal mill; highvoltage; permanent magnet direct drive; one variable multi control