无刷双馈电机能量传递关系和功率因数特性的实验研究

Experimental Study on Energy Transmission and Power Factor Characteristics of Brushless Doubly-fed Machines

在不同的运行方式下,无刷双馈电机控制绕组具有能量双向流动的特点。目前对该课题已有的研究成果中定性分析多、实验数据少,且没有正确反映能量传递关系。提出对应于一定的频率和负载转矩,无刷双馈电机在亚同步电动(或超同步发电)状态下控制绕组的能量并非总是回馈到逆变器,而是与其端电压、相应频率下的开路电压以及逆变器的直流侧电压有关。在此基础上,将电机的功率因数、运行效率以及稳定性与能量传递关系结合起来进行研究。样机实验结果表明,双馈运行状态下对应于某一确定的转速和负载,在满足系统稳定运行的条件下,调节控制绕组电压使其约为对应的开路电压,可以提高电机的运行效率。

Control winding of the brushless doubly-fed machine is characterized by bidirectional energy transmission in different working modes.So far,relevant researches have emphasized on qualitative analysis while experimental data are insufficient and experimental results do not properly reflect energy transmission.In view of the above,the paper concludes that the power is not always back to the inverter in sub-synchronous motor state,since it depends on its terminal voltage,open-circuit voltage corresponding to a certain frequency and DC bus voltage.On this basis,taking into consideration the motor power factor,efficiency and stability and energy transfer relations＇ studies,the experiment was done under doubly-fed state and at certain speed and load.The results show that,higher efficiency of BDFM can be obtained when the control winding voltage is approximate to the open-circuit voltage on the premise of maintaining system stability.