大功率电流源型变频器共模电压研究

Study of common-mode voltage in high-power current source converter

为了解决电流源型变频器中存在共模电压的问题,提出了一种采用一体化直流电抗器的方法。该方法在传统电流型变频器的直流环节加入共模电感,以减小系统的共模电流和共模电压。对采用一体化电抗器的3种电流源型变频器的共模电压进行了系统分析,并对一体化直流电抗器的共模电感值进行选择。其中将整流器侧电容中性点与逆变器侧电容中性点连接在一起时,共模电压和共模电流都得到了明显抑制,降低了共模噪声对电机的影响。由于省去了用于抑制共模电压的隔离变压器,这种结构使得变频调速系统结构简单,运输方便,成本降低。仿真结果说明了分析的正确性。

It is proposed to add an integrated DC link reactor into the DC sect oi traditional current source converter to reduce its common-mode voltage. The common-mode voltage of current source converter with integrated DC link reactor is analyzed for three topologies and the appropriate value of common-mode inductance is chosen. When the neutral point of capacitor at rectifier side and that at inverter side are connected together,the common-mode voltage and current are well restrained. As the isolation transformer is cancelled,the proposed current source converter is simple and cheap. Simulative results verify the correctness of the theoretical analysis.