功率变换器多开关状态下的传导电磁干扰预测

Conducted Electromagnetic Interference Prediction for Power Converters Under Variable Switching Conditions

针对一个周期内多开关状态的功率变换器,建立基于IGBT模块的等效噪声源模型,并提出分区域的方法预测其传导电磁干扰,建立一个涵盖整个交流输出周期内不同负载电流水平的噪声源模型的集合。分析一个开关周期内由各个开关脉冲引起的传导干扰噪声的关系,一个交流输出周期内总的噪声通过频域内的叠加来获得。保持传播路径一致的情况下,将整个交流输出频率信号划分成4个区域,在每个区域内,传导干扰噪声用相应的噪声源模型计算,一个交流输出周期内的噪声通过4个区域内的结果联合计算得出。实验和仿真结果表明,预测结果有较好的精确度,可以实现整个传导干扰频段内的电磁干扰噪声预测。

A new frequency-domain modeling approach based on IGBT module was proposed for predicting conducted electromagnetic interference（EMI） in power converter system under variable switching conditions.A practical approach is to build source models for a family of selected current levels covering the whole operating range.The relationship of each switching pulse in a switching cycle is analyzed,the whole conducted electromagnetic interference can be calculated by the sum of different zones.As a result,the whole line cycle is divided into four operating zones.Within each zone,the EMI noise can be calculated using one corresponding source model,and the noise for one line cycle can be calculated by combining the results of the four zones having four different source models but the same propagation path.Experiments and simulations show that the proposed approach can predict the electromagnetic interference noise accurately in a power converter for the entire conducted electromagnetic interference frequency range.