The STW.bms (Battery Main Supervisor) is the central control unit of the battery system. It is connected with the CAN vehicle architecture and ensures the safety of the entire battery system. Over and above this, the BMS provides the required condition determination and performance prediction.
The STW.bms contains three processors for maximum reliability and safety. It collects all the information from the sensor modules, the cell sensor circuits and the power measurement board, calculates the battery system status and controls the HV contactor. The state of charge (SOC) is determined through a charge balance (Coulomb counting) and automatic recalibration. The power possible in charging and discharging mode is estimated through an adaptive algorithm. The integrated insulation monitor also measures the insulation value of the traction network over and above the drive converter. In addition, different pre-charging and shutdown devices as well as different HV interlock safety contacts can be connected and monitored.