等效正弦的分级变频软启动器研究与设计

Research and design of discrete frequency soft starter based on equivalent sine wave principle

针对传统软启动器起动转矩过小而无法满足重载起动的问题,利用分级变频原理,同时借鉴恒压频比的电机变频调速理论,提出了一种基于等效正弦的分级变频软启动控制方法,可以降低电机定子相电流的谐波含量,减小电机在分级变频软启动过程中的转矩脉动,达到平稳起动重载的目的。通过搭建基于等效正弦的7阶段控制系统仿真模型,验证了该理论的合理性。在此基础之上,研制了分级变频软启动器实验样机,试验结果表明,所提出的方法可有效的改善电机的起动电流波形,与仿真结果吻合。

Due to the torque of traditional soft starter is low and cannot meet the starter of heavy load needs, by using discrete frequency theory and VVVF control strategy for reference, a control method of discrete frequency soft starter was put forward based on equivalent sine. This method lowers harmonic content of motor stator＇ s phase current and reduces torque ripple during the process of discrete frequency soft starting so as to stabilize heavy load starting. Simulation model of seven-phase equivalent sinusoidal control system testifies the reasonability of this theory. On the basis of the above, discrete frequency soft starter experimental prototype was produced. The experimental result indicates that this method improve current waveform of motor starter effectively and is consistent with simulation result.