Control of the active discharge of a high-voltage intermediate circuit

A device for actively discharging a high-voltage intermediate circuit contained in a power electronics module for providing an operating voltage for an electric drive machine of an electrically powered vehicle with an intermediate circuit capacitor, which device comprises a control device for controlling the active discharge and a discharge circuit that can be actuated by the control device for actively discharging the high-voltage intermediate circuit, which has a semiconductor switch and a discharge resistor connected in series thereto, characterized in that the discharge resistor is made up of an SMD resistor or multiple SMD resistors, and in that the control device is adapted for the active discharge to actuate the semiconductor switch with a pulse width modulated signal, wherein the frequency and the pulse duty factor of the pulse width modulated signal at the beginning of the active discharge are selected such that the semiconductor switch is closed for no longer than 10 μs, and the pulse duty factor of the signal is then increased depending on the current voltage level of the high-voltage intermediate circuit such that a power loss is generated at the discharge resistor over the duration of the active discharge, which comes as close as possible to a maximum permissible power loss of the discharge resistor but does not exceed it, and in that the power loss is distributed more evenly over the entire discharge period than with a constant pulse duty factor.