Active EMI Reduction Technique of Active Front End (AFE) Drives Based on Randomized Switching Frequency PWM

Random modulations are considered to be one of the viable solutions for mitigating conducted electromagnetic interference (EMI) in power converters. However, there are rarely literatures investigating this technique in grid-tied active frond end (AFE) drives. In this paper, a modulation scheme for grid-tied AFE converter based on uniformly randomized switching frequency PWM is proposed. The proposed technique features the advantage that it requires no additional hardware modification of the grid-tied AFE motor drive system but some convenient algorithm adjustment in digital implementation. Simulation and experimental results are provided to verify the effectiveness of proposed randomized switching frequency PWM technique in reducing and smoothing the conducted emissions’ undesirable peaks within concerned frequency range.