起重机电机拖动系统负载跟踪控制

为了使起重机电机拖动系统的电机以给定转速实时跟踪突变的负载转矩,通过等效折算得到了起升机构电机转子侧的等效转动惯量、等效负载转矩和电机拖动系统动力学方程;建立了按转子磁链定向同步旋转坐标系;应用转差角频率设计了跟踪负载转矩的矢量变频控制系统.实例计算表明:闭环系统的空载起动时间比开环系统快0.34 s,电机平稳起动,起动阶段开环和闭环系统的峰值电磁转矩差值达148 Nm;闭环系统电机消耗的电功率(综合节能的百分比)小于开环系统;在起动阶段,开环系统的峰值功率是闭环系统峰值功率的2.5倍.电机在空载起动阶段约节能50%,平稳运行阶段约节能30%. 

Research on Load's Tracking Control for Crane's Motor Driving System

In order to control a crane motor to real-time track the abrupt load torque with a given rotational speed for the motor driving system, the equivalent moment of inertia and equivalent load torque on the rotor of the hoisting mechanism and the dynamic equation of the motor driving system were derived through equivalent conversion. Then a system of synchronous rotating coordinates was constructed according to rotor flux linkage orientation, and a vector variable frequency control system for tracking load torque was designed based on the slip angle frequency. The results of a case study show that the starting time of the close-loop control system with no load was 0.34 s faster than that of the open-loop system, the motor could start stably, and the difference of electromagnetic torque's peak value was 148 Nm between the open-loop system and the close-loop control system. In addition, the electric power consumption of the motor in the close-loop control system was less than that in the open-loop system; especially at the motor's starting stage, the motor peak power of the open-loop system was 2.5 times that of the close-loop control system. In brief, under the designed close-loop control, the motor could save about 50% energy during the starting stage and about 30% during the stable running stage.