摘要
模型预测直接功率控制(MPDPC)以其原理简单、动态响应快和控制目标灵活等优点在并网变换器控制中得到了广泛关注。它利用系统模型来预测下一时刻的有功功率和无功功率,通过枚举比较得到使给定功率和反馈功率之间误差最小的电压矢量,相比传统的基于矢量表的直接功率控制具有更好的动态和稳态性能。为了进一步提高稳态性能并降低采样频率,提出一种基于双矢量的改进模型预测直接功率控制,即把一个控制周期分配给一个非零矢量和一个零矢量,通过优化非零矢量的作用时间来进一步减小功率脉动。通过合理安排矢量作用顺序甚至可以获得比传统MPDPC更低的开关频率而且稳态性能更好。在15 k W双馈风力发电系统上的仿真结果表明,相比传统MPDPC,所提出的双矢量MPDPC能够以更低的采样频率实现快速平滑的并网同步和灵活的有功、无功控制,并且开关频率更低,具有较大的实用价值。
The model predictive direct power control( MPDPC) is attracting wide attentions in the control of grid-connected converters due to the merits of simple principle,fast response,and flexible control aims. It uses the system model to predict the future value of active / reactive power and obtains the best voltage vector minimizing the power errors by enumeration. Compared to the conventional switching table based direct power control( DPC), MDPPC features better steady and dynamic performance. To further improve the steady state performance and reduce the sampling frequency,this paper proposes a two-vectors-based MPDPC by allocating one non-zero vector and one null vector during one control period. The power ripples are significantly reduced by optimizing the duration of the non-zero vector. Lower switching frequency with better steady state performance can be obtained by arranging the vector sequence in a more reasonable way. Simulation results from a 15 k W doubly fed induction generator( DFIG) system indicate that,compared to the conventional MPDPC,the proposed twovectors-based MPDPC,with low sampling frequency,can achieve fast and smooth grid synchronization,flexible regulation of active / reactive power,and lower switching frequency. Hence,it is very practical for real applications.
出处
《电工技术学报》
EI
CSCD
北大核心
2016年第5期69-76,共8页
Transactions of China Electrotechnical Society
基金
国家自然科学基金(51207003
51577003)
北京市科技新星计划(xx2013001)资助项目
关键词
双馈电机
并网同步
发电
模型预测直接功率控制
双矢量
Doubly fed induction generator
grid synchronization
power generation
model predictive direct power control
two vectors
