低成本高性能的共模和差模噪声分离技术

为了正确设计滤波器的参数，必须将共模和差模信号从线性阻抗稳定网络所测得的混合信号中分离出来。该文提出一种软硬件结合的低成本高性能的噪声分离技术，该技术共模信号是通过3个电阻组成的差模抑制网络分离出来的，差模信号则是根据共模和差模的定义，由软件方法计算得到的。文中对使用该方法可能存在的误差进行了估算。以1台600W 的直流电机系统产生的传导干扰为例，用此方法分离出共模和差模噪声信号，并根据分离结果设计了滤波器参数，最后给出系统接入此滤波器后传导干扰的频谱图。测量结果表明该系统的传导干扰发射在整个频段内均不超标，从而也证明了分离方法的有效性和实用性。

Common and Differential Mode Noise Separate Technology With Low Cost and High Performance

For conduction emission noise,the separation of the common and differential mode noise is important for determining parameters of proper filter. This paper proposes a novel noise separation technology with low cost and high performance which combines hardware with software. The common mode(CM) noise is separated by differential mode rejection network(DMRN) which is composed of three resistors. The differential mode(DM) noise is shown by software method based on the definition of CM and DM. This paper estimates the error brought by this separation technology. Conducted emission produced by a 600W DC motor system was separated by the novel separation technology. The parameters of filter was designed according to the separation result. Conducted inteference produced by this motor was measured after this designed filter was connected into the motor system. Experiment results indicate that it is complied with electromagnetic compatible(EMC) standard in the whole conducted interference frequency band and prove that this separation technology is very valid.