CAJ | 학술논문

IEC 61000-4-7:2002标准推荐的谐波间谐波测量新方法在同步采样下对非平稳信号具有良好的测量精度,但在非同步采样下测量精度较差,在各次谐波和间谐波相对相位变化下测量值会不同.为提高IEC新方法测量精度并保持测量值恒定,提出基于IEC新方法与全相位谱分析相结合的改进方法.该方法利用全相位谱分析具有优良的抑制频谱泄漏和相位不变性特点,实现在非同步采样下对多种典型非平稳信号谐波间谐波的精确测量,并与IEC新方法和传统加二阶余弦窗IEC新方法对比.仿真结果表明,所提出的改进方法非常适用于在非同步采样下谐波间谐波测量,即使各次谐波和间谐波相对相位出现变化,测量值仍然具有较高的精度并能保持恒定.
IEC 61000-4-7:2002표준추천적해파간해파측량신방법재동보채양하대비평은신호구유량호적측량정도,단재비동보채양하측량정도교차,재각차해파화간해파상대상위변화하측량치회불동.위제고IEC신방법측량정도병보지측량치항정,제출기우IEC신방법여전상위보분석상결합적개진방법.해방법이용전상위보분석구유우량적억제빈보설루화상위불변성특점,실현재비동보채양하대다충전형비평은신호해파간해파적정학측량,병여IEC신방법화전통가이계여현창IEC신방법대비.방진결과표명,소제출적개진방법비상괄용우재비동보채양하해파간해파측량,즉사각차해파화간해파상대상위출현변화,측량치잉연구유교고적정도병능보지항정.
The new harmonic and interharmonic measurement method with good measuring accuracy for non-stationary signals under synchronous sampling is recommended by IEC 61000-4-7:2002 standard, but it shows poor measuring accuracy under asynchronous sampling, and the results are variable when relative phase of harmonic and interharmonic changes. To make up the deficiency above, this paper presents an advanced method which combines IEC standard framework with all-phase FFT. The method has the excellent property of inhibiting spectral leakage and the feature of phase invariance of all-phase FFT for detecting various typical non-stationary signals, and then is compared with the IEC method and IEC order cosine window method. Simulation results demonstrate that the advanced method is suitable for harmonic and interharmonic measurement for asynchronous sampling, even though the relative phase of harmonic and interharmonic changes, the measurement results are still with high accuracy and keep constant. This work is supported by the Natural Science Foundation Project of CQ CSTC (No. cstcjjA9001).