How to select the filter for the PCS communication interface of an energy storage system?

The selection of filters for PCS communication interfaces (such as CAN, RS485, Ethernet) needs to be based on the interface characteristics and noise type. For differential buses, the main goal is to suppress common-mode noise while ensuring signal integrity. Selection criteria:

1. Interface standard and speed: For example, CAN FD requires a common-mode inductor with good high-frequency characteristics, such as the CML series, whose impedance curve must cover the harmonic frequencies corresponding to the data rate.

2. Protection level: In addition to filtering, ESD/TVS protection is often required. For example, a common-mode filter with integrated ESD protection can be selected, or it can be used in conjunction with ESD devices.

3. Mounting method: Select surface mount or through-hole package according to the board space.

4. Key parameters: Pay attention to common-mode impedance, rated current, DC resistance, and bandwidth. For example, when selecting a filter for an RS485 interface, it is necessary to ensure that the insertion loss of the common-mode inductor is small enough within the transmission frequency range to not affect signal quality.