中文摘要：

为了评估和抑制现场运行设备的电磁干扰（electromagnetic interference，EMI），对其EMI频谱进行实时准确的估计十分必要。基于快速傅里叶变换（Fourier transformation，FFT）的实时频谱分析要解决数据量和精度之间平衡问题，提出一种实时估计变流器EMI频谱的综合方案。该方案先通过低频率分辨率的FFT运算获得干扰频谱的粗略情况，然后选择EMI峰值进行以频率调制为基础的频谱局部精细化，来减少实时计算所需的数据量；再通过加优选窗函数以减小频谱能量泄漏；最后采用新提出的对称移位相位差（symmetrical time—shift phase difference，STSPD）法对栅栏效应进行修正，获得EMI峰值较为精确的参数。通过对比研究，找到了当峰值频率点比较接近时具有最佳精度的窗函数和STSPD修正法的组合。通过DC／DC变换器的实验证实了该综合方案快速、准确。

英文摘要：

To evaluate and suppress electromagnetic interference （EMI） of the operational electrical equipment, it is essential to estimate EMI spectrum accurately in real time. The issue of balance between volume and accuracy of data must be resolved in real-time spectrum analysis based on the fast Fourier transform （FFT）. In this paper, a synthesis scheme was proposed that can estimate EMI spectrum of converters in real time. Firstly, in order to decrease the data size for real-time calculation, the rough spectrum of EMI was calculated through FFT on low resolution, and then the EMI peaks were selected to be locally zooming based on modulation in spectrum. Secondly, the best window function was adopted to reduce spectral energy leakage. Finally, a new set of symmetrical time-shift phase difference （STSPD） methods, which was designed in this paper, was used to correct the errors caused by picket-fence effect. And then the high accurately estimated parameters of EMI peak will be obtained. The optimal combination of window functions and STSPD correcting methods, which has the highest accuracy when peak frequencies are close each other, was found through screening. The experiment results of the DC/DC converter confirm that the synthesis scheme is fast and accurate.