铁路集装箱起重机异步电动机调压节能的优化方法

铁路集装箱起重机异步电动机具有恒转矩运行和变工况负载的特性,基于异步电动机T型和Γ型等效电路,将定子的铜耗和铁耗看作是仅与定子电压有关的不变损耗,将转子的铜耗看作随负载转矩变化的可变损耗,推导出异步电动机电气总损耗计算式和最优调节电压计算式,并通过实例进行验证。研究结果表明:当转差率为0.01～0.03、起重机电机稳定运行时,按照近似转差率计算的起重机负载转矩误差不超过1.8N.m;在起重机的工作电压高于220V时,电气总损耗的计算误差几乎为零;最优调节电压及其误差随着起重机负载转矩的增加而增大,但在起重机的工作电压范围之内,最优调节电压误差不超过7V;电动机按照起重机负载转矩的变化适时调压时,其电气总损耗小于380和220V恒压驱动的电气总损耗,尤其是在起重机空载运行时,具有显著的节能效果。

Optimization Method for Voltage Regulation and Energy Saving ofthe Asynchronous Motor of Railway Container Crane

The asynchronous motor of railway container crane has the characteristics of constant torque operation and variable condition load.Based on T-shape and Γ-shape equivalent circuits of the asynchronous motor,the copper loss and iron loss of stator were regarded as invariable losses that were only related to stator voltage,and the copper loss of rotor was regarded as the variable loss that changed with the load torque.The calculation formulas for electric total loss and optimal voltage regulation of asynchronous motor were derived,and were validated by example.Results show that,when the slip ratio is 0.01~0.03 and the crane motor is in stable operation,the error of the container crane’s load torque obtained according to the approximate slip ratio is no more than 1.8 N·m.The calculation error of the electric total loss is almost zero when the working voltage of the crane is higher than 220 V.The optimal voltage regulation and its error will increase with the load torque of the crane.However,the error of the optimal voltage regulation will be no more than 7 V within the working voltage of the crane.As the motor timely regulating voltage according to the change of the load torque of the crane,its electric total loss is less than that under the constant voltage driving mode with 380 and 220 V.The energy saving effect is prominent especially when the crane is in no load operation.