摘要
模块化多电平变换器以其优越的性能在中高压大功率电能变换场合得到了广泛的研究和应用。推导了模块化多电平变换器(modular multilevel converter,MMC)的离散状态方程,针对MMC多输入多输出的非线性特性,提出一种基于有限控制集合的简化模型预测控制,可以有效减少模型预测控制所需的循环计算和预测值计算次数。所提模型预测控制由最优输出电平求解和电容电压平衡控制两部分组成。首先求取满足交流电流和环流控制要求的桥臂输出电压电平,并以此电平及其邻近的电平为有限控制集合,考虑上下桥臂电容电压之和与之差的控制,求得桥臂输出电平最优解;电容电压平衡控制则由电压预测值排序法实现,用电压增量表示附加的开关动作,修正电容电压预测值后再进行排序,实现电压平衡控制并降低平均开关频率。在PSCAD/EMTDC中搭建MMC时域仿真模型,仿真结果验证了所提方法的正确性和有效性。
With the attractive features, modular multilevel converters are widely utilized in the area of high-voltage and large-capacity applications. The discrete state equation was derived, as the modular multilevel converter （MMC） was a multi-input multi-output system, a simplified finite control set model predictive control strategy was proposed, which could reduce the computing cycles and predictive value calculating amounts effectively. Optimal output voltage level calculations and modified capacitor Voltage balancing control were included in the proposed control strategy. Firstly, an output voltage level was solved, based on ac-side current and circulating current equations; with this voltage level and its nearest levels, the finite control set was built. Considering the control of summation and difference of capacitor voltages in upper and low arms, the optimal output level was solved. A modified voltage balancing control method was also presented. An addition switch action was introduced into sorting algorithm as a voltage increment; in this way, voltage balancing control and switching frequency reduction were achieved effectively. Performances of the proposed control strategy were evaluated based on the time-domain simulation model in PSCAD/EMTDC; the simulation results verified the effectiveness of the proposed control strategy.
出处
《中国电机工程学报》
EI
CSCD
北大核心
2016年第5期1366-1375,共10页
Proceedings of the CSEE
基金
国际合作项目(2013DFB60250)
湖南省研究生科研创新项目(CX2014B130)~~
关键词
模块化多电平变换器
模型预测控制
有限控制集合
电容电压平衡控制
预测值排序
modular multilevel converter （MMC）
modelpredictive control
finite control set
capacitor voltagebalancing control
predictive value sorting
