【摘要】 针对不对称交流电网下模块化多电平换流器型高压直流输电系统(MMC-HVDC)的传统不平衡控制策略存在的诸多缺点,提出两种改进的不平衡控制方法:电流环模型预测控制方法和模型预测直接功率控制方法。两种方法分别实现了对MMC交流侧电流的控制和对MMC交流侧有功和无功功率的直接控制。详细描述了两种控制方法的控制原理及设计过程,与传统的双矢量控制策略从控制结构复杂度、稳态性能和动态性能等方面进行了对比分析。将模型预测直接功率控制与功率补偿策略相结合,以分别实现不对称电网下抑制负序电流、抑制有功波动和抑制无功波动3种控制目标。在PSCAD/EMTDC中搭建了5电平MMC-HVDC模型,验证了该文所提两种控制方法的正确性和有效性。更多还原

【Abstract】 Aiming at eliminating the existing shortcomings of the traditional unbalanced control strategy for high voltage direct current transmission based on modular multilevel converter( MMC-HVDC) under asymmetry ac system,this paper proposes two improved unbalanced control methods,i. e. the current loop model predictive control and the model predictive direct power control. The two proposed methods achieve ac-side current control and ac-side active power and reactive power control of MMC,respectively. The control principle and the design process of the two methods are described in detail. In addition, the traditional dual vector control strategy is compared with them in respect of the control structure complexity, the steady-state performance, and the dynamic performance. In order to achieve three control targets under the asymmetric ac system,i. e. suppressing negative current,eliminating active power ripples,and removing reactive power ripples,the model predictive direct power control is combined with the power compensation strategy. To validate the correctness and the effectiveness of the two proposed control methods,a five level MMC-HVDC model is set up in PSCAD / EMTDC.更多还原