How to select the common mode inductor for EPS output?

When selecting a common-mode inductor for the EPS output side, the following key parameters must be considered:

1. Rated current: Must be greater than the effective value of the maximum output phase current, and a certain overload and waveform distortion margin must be taken into account.

2. Impedance characteristics: Sufficiently high impedance is required in the target suppression frequency band (e.g., 150kHz-30MHz). For example, the number in the CM-L series model represents the impedance value (ohms) at a specific frequency, which needs to be selected based on the noise spectrum.

3. Saturation current: Must be much higher than the peak value of possible transient unbalanced current to prevent inductor saturation leading to impedance drop failure.

4. DC resistance (DCR): Affects conduction loss and temperature rise, and must be within the allowable range of system efficiency.

5. Self-resonant frequency: Should be higher than the highest noise frequency that needs to be suppressed. When selecting, the actual tested noise spectrum should be considered to ensure that the inductor can provide sufficient attenuation at frequencies exceeding the standard, and to coordinate with the output X/Y capacitor parameters to avoid resonance peaks.