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BQ76952: BQ76952

Part Number: BQ76952

BQ76952 and regenerative braking, is an action required by the BQ76952 IC ?

If generative braking is activated and the low-side MOSFETs or IGBTS are pulsing from the inverter, should the CHG pin of the BQ76952 be activated ? To my understanding, the answer is yes once the voltage in the large capacitor voltage is higher than the battery nominal or maximum voltage.

If yes or no, is there any design consideration that I or the community should be aware of when designing an inverter that is capable of regenerative braking?

Were should the large capacitor be connected, on the battery side or as close as possible to the inverter high voltage terminal ?

For your information, my battery design pack is 144Vdc, 100A and using LiFePO4 cell.

Donald

  • Hi Donald,

    We do not have specific experience with regenerative braking and how the inverter would work in this system as our expertise is more on the battery pack. If the CHG FET were to be activated and the battery voltage is at or above the maximum allowed per the cell manufacturer, then the battery could be overcharged and result in an unsafe situation. So it seems necessary to have an alternative path for the regenerated current to flow into if the battery is already fully charged.

    Best regards,

    Matt

  • Thank you Matt, I did forget that my aplication is for an EV.

    I do understand that the inverter should interrogate the BMS of the current voltage value of the battery voltage. If the battery is shown to be at its maximum voltage value, I agree that an alternative path is required and could be a resistor and an IGBT (dynamic breaking) to waste the excess of energy.

    Best regards,
    Donald.