摘要
三相电网电压不对称时存在相位差,会影响电网运行的安全。为了对谐波的实时性及精度进行检测。提出一种改进的dq坐标变换的谐波和无功电流检测法:即用得到的对称性较好且频率与电网电压相同的基波正序电流或基波正序有功(无功)电流代替电网电压进行锁相得到dq变换所需的正余弦信号,避免了三相电压不对称带来的检测精度和实时性问题。利用MATLAB/SIMULINK仿真软件进行建模仿真,仿真结果表明,提出的方法提高了检测的精度和实时性,同时具有良好的动态响应速度及跟踪性能且实现简单、运用灵活。
When three-phase voltages are unbalanced, the circuit structure and mathematical operation of tradi- tional dq harmonic and reactive currents detection method are both comparatively complicated so that the real-time performance and accuracy will be decreased. A novel detection method of unbalanced three-phase voltage system was proposed. The symmetry of fundamental positive-sequence current or fundamental positive-sequence active （reac- tive） current is comparatively better and its frequency is the same as the voltage＇ s,so it is used as the input of PLL rather than the voltage to get the sine and cosine signal that dq transformation needs, thus avoiding the problems that unbalanced three-phase voltages cause. This method was built into model and simulated by MATLAB/SIMULINK. Simulation results prove that this improved method raises the detection accuracy and real-time performance, and it has good dynamic response speed, as well as tracking characteristic, and can be implemented simply and applied flexibly.
出处
《计算机仿真》
CSCD
北大核心
2012年第11期336-340,共5页
Computer Simulation
关键词
坐标变换
锁相环
低通滤波器
无功电流
Coordinate transformation
Phase locked loop（PLL）
Low pass filter（LPF）
Reactive currents
