摘要：针对传统采用下桥短路方式以获得电机相电流信息的转速跟踪控制方法中电流过大的问题，本文提出了一种电流幅值控制的转速跟踪策略。利用异步电机剩余反电动势，对三相全桥电路采用特定的斩波调制方式，可以在转速跟踪期间将电机相电流恒流控制，避免出现电流过大而造成变频器故障。另外电流幅值控制可以获得平稳的电磁转矩以及尽可能延长剩余反电动势的作用时间，能有效的提高转速信息获取的准确性。最后在获取了电机转速以及电角度后，通过电流电压模型自适应法构造速度开环、电流闭环的工作方式，使磁链观测模型的转速估计环内部参数达到稳定，以此在切入速度电流双闭环的工作模式后可以最大限度的降低转矩和电流冲击。实验证明：该控制方案具有结构简单，易于实现，同时具有较强的通用性和鲁棒性。
关键词：异步电机；磁链观测；转速跟踪；自适应PI；电流幅值控制

Abstract: To solve the excessive current problem of the traditional shortcircuit method in speed tracking process, a method of speed tracking based on current amplitude control was proposed. Using the remaining motor EMF with the specific chopper modulation of the threephase fullbridge circuit, can control the phase current to the constant amplitude during the speed tracking process. In additional, the current amplitude control method can obtain the smooth motor torque and prolong the action time of the remaining EMF, which can effectively improve the speed tracking accuracy. Finally, in order to get the stability inside parameters of the flux observation and speed estimation model, a speed openloop and current closedloop system was built by the current and voltage adaptive control method. Experimental results show that the proposed scheme has the advantages of simple structure, easy realization, also has the versatility and robustness.
Key words: induction motor; flux observation; speed tracking; adaptive PI; current amplitude control