Apparatus and method for discharging a capacitor for use in the electric power system of a vehicle with electric drive

摘要

A discharge device (11) and method for actively discharging a main capacitor (C filter ); a discharge branch (13) is connected in parallel to the main capacitor (C filter ) and is provided with a discharge transistor (TD); a control device (14) is connected to the gate/base terminal of the discharge transistor (TD), controls the discharge transistor (TD) by biasing the discharge transistor (TD) to conduction mode when discharging the main capacitor (C filter ) is required, and has a safety capacitor (C safe ) which is interposed between the gate/base terminal of the discharge transistor (TD) and a power source which is charged when the discharge transistor (TD) is biased to conduction mode, thus determining a progressive reduction of the voltage/current at the gate/base terminal of the discharge transistor (TD) to bias the transistor (TD) to the isolated state after a time interval from the starting instant of the conduction of the discharge transistor (TD).