基于无差拍电流控制的MMC-HVDC系统控制策略研究

随着电平数的增加,基于dq0旋转坐标系MMC-HVDC的控制器运算量会非常大。为了提高运算速度,根据MMC换流器的等效电路设计了基于三相静止坐标系下的MMC-HVDC系统控制器。该控制器将无差拍电流控制与最近电平调制算法相结合,并对电流参考值的采样选取方法进行了改进,提高了控制器精度。该控制器不仅动态响应快,精度高,实现了解耦控制,而且减少了坐标转换与PI调节环节,降低了控制系统的运算量。通过在PSCAD/EMTDC下建立MMC-HVDC的仿真模型,仿真结果验证了控制器的有效性。

Study of control strategy for MMC-HVDC system based on deadbeat current control

With the increment of level, there is a large amount of the computation for the controller of MMC-HVDC system. To speed up, according to the equivalent circuit of MMC converter, this paper designs the controller of MMC-HVDC system based on the three-phase static coordinate system. The controller combines deadbeat current control with nearest level modulation (NLM), and improves the sampling selection method of current reference value for the precision. The proposed controller realizes decoupling control with fast dynamic response and high precision, decreases the amount of system computation with less PI regulator and coordinate transformation. The MMC-HVDC simulation model is established in PSCAD/EMTDC environment and the simulation results verify the validity of proposed controller.