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Impact of Interleaving on EMI Noise Reduction of Paralleled Three Phase Voltage Source Converters
Fig. 1. Interleaved 2L VSI DC-fed motor drive system.
To study the impact of interleaving on system EMI performance, the equivalent circuit is given as Fig.2, which shows that interleaving will change the noise sources for both CM and DM noise. The impact of interleaving can be predicted using a double Fourier integral analysis and the selection of optimized interleaving angle is related to the system noise propagation path impedance as shown in Fig.3. Both simulation and experimental results prove that by using an optimal interleaving angle the EMI noise can be reduced by 10~12dB in the impedance resonant frequency range, which can reduce the EMI filter size significantly.
Fig. 2. (a) Equivalent circuit for converter output DM and CM noise of dc-fed system with interleaving: DM equivalent circuit.
Fig. 2. (b) CM equivalent circuit.
Fig. 3. Voltage noise source magnitude reduction on different order harmonics of interleaving with different interleaving angle.
Fig. 4. Experimental ACCM noise (180° interleaving: green and 13° interleaving: red).
