摘要
从并网逆变器控制性能的比较可知,常规的数字控制不如模拟控制.为此,以常用的准比例谐振电流控制器为例,采用传统模型、1阶惯性模型、离散化模型,分析了数字控制采样、零阶保持和滞后一拍对逆变器稳态和动态性能的影响.得出结论：数字控制使控制器和控制对象特性发生变化,系统阶数由3阶升高为4阶,相位滞后增大,开关频率及其整数倍频率出现谐振,并伴随有相位的跳变,控制参数的稳定域缩小;受稳定性的制约,稳态精度和动态性能也下降,采样频率越低时上述影响越突出.一种基于误差电流衰减的预测控制被提出用于抑制数字控制的影响.仿真和实验结果表明预测控制能减小稳态误差,动态调节时间由10,ms减少到小于5,ms,电感估计标幺值在0-1.53内变化,系统具有良好的鲁棒性.
When the control performance of grid-connected inverter is considered, conventional digital control is not as good as analog control. To explain this phenomenon, the commonly-used quasi proportional resonant current controller was discussed as an example. The traditional model, one order inertia model and discrete model were employed to analyze the effects of sampling, zero order holder and one-beat delay control on the steady and dynamic performance of the inverter. Conclusions are as follows： digital control changes characteristics of the controller and the plant; the order of system characteristic equation increases from 3 order to 4 order and the phase lag increases; the amplitude resonance and phase jump arise at the switching frequency and its multiple frequency; the stable region of control parameters reduces; steady-state error becomes larger and dynamic performance declines because of system stability. The above effect becomes more serious when sampling frequency gets lower. A predictive control strategy based on current-error-attenuation was proposed for suppressing effects of digital control. The simulation and experimental results show the predictive control strategy reduces the steady-state error, dynamic adjustment time decreases from 10,ms to less than 5,ms. The system is rather robust when the inductance per-unit changes from 0 to 1.53.
出处
《天津大学学报（自然科学与工程技术版）》
EI
CSCD
北大核心
2016年第5期472-479,共8页
Journal of Tianjin University：Science and Technology
基金
高等学校博士学科点专项科研基金资助项目(20120032110070)
国家国际科技合作专项项目(2013DFA11040)
国家自然科学基金资助项目(61172014)
关键词
数字控制
准比例谐振
并网逆变器
稳定域
预测控制
digital control
quasi-proportion resonant
grid-connected inverter
stable region
predictive control
