METHOD AND APPARATUS FOR COMPENSATING FOR CHARGE DIFFERENCES BETWEEN THE BATTERY MODULES OF A BATTERY SYSTEM WITH AN OUTPUT VOLTAGE WHICH IS ADJUSTABLE IN STAGES

摘要

The present invention relates to a method for compensating for charge differences between the battery modules (30, 31, 40, 41) of a battery system (20), which is used in a drive system (10) and has an output voltage which is adjustable in stages, during the standstill of the drive system (10), wherein the battery system (20) is electrically coupled to a converter (100) of the drive system (10) by means of an intermediate circuit (70) having at least one intermediate circuit capacitor (80), the intermediate circuit capacitor (80) is discharged when a charged state is present, energy (W) is removed from at least one first battery module (30, 31) and is buffered in the intermediate circuit capacitor (80) by charging the intermediate circuit capacitor (80) to a predefined intermediate capacitor voltage (Uc), and the energy (W) buffered in the intermediate circuit capacitor (80) is stored in at least one second battery module (40, 41) with a second state of charge which is lower than the first state of charge.