长线路轻负荷永磁同步电机功率因数的现状及改进途径

Present Status and Improvement Approach of Permanent Magnet Synchronous Motor's Power Factor under Long-Line Conditions

以油田电网为实例,通过对现场运行的永磁电机的大批量测试发现,在供电线路很长的情况下,其功率因数可能显著降低,从而导致其不节能或者节能效果不好。主要原因是电压偏差较大导致与永磁电机的感应电势不匹配;对于轻载运行的永磁电机,即使电压偏差值仍然在国家标准允许的范围,功率因数也可能降低至异步电机的水平。提出采用电源电压自匹配稀土永磁电机及相关控制系统,可有效提高永磁电机对电源电压偏差的适应性,并提供了相应的技术方案。实测表明,在电压偏差7%且电机的负载率在20%的条件下,可使永磁电机的功率因数从约0.75提高到0.95以上。

Taking oil field power grid as an example,the large quantities of the field test on the operation situation of rare-earth permanent magnet synchronous motor（PMSM） were carried out and analyzed,and it was found that the power factor（PF） of PMSM may be obviously reduced with very long supply lines,which leads to less or no energy saving.The main reason was that larger voltage deviation didn＇t match the PMSM＇s electromotive force（EMF）.For the PMSM with light load,even if the voltage deviation was still in the range of national standards allowed,the PF may also be reduced to asynchronous motor＇s level.The rare-earth PMSM with self-match supply voltage and its control system were proposed,which could effectively improve the adaptability of the PMSM to the supply voltage,and the corresponding technical scheme were also presented.The actual test results showed that the PF of PMSM could increase from about 0.75 to above 0.95 under the conditions of 7% voltage deviation and 20% rated load or so.