Method for operating a frequency converter, which operates an electrical machine on an electrical network, - wherein the frequency converter has a feed unit and a converter, which are interconnected via a DC voltage intermediate circuit, in which an intermediate circuit capacitance is supplied by at least one intermediate circuit capacitor, - wherein the network-side feed unit is designed to convert between a network AC voltage and a DC voltage (U 48), which is supplied in the intermediate circuit, and the converter is designed to convert between the DC voltage (U 48) and an AC voltage for the electrical machine, - wherein the intermediate circuit has a semiconductor switch, which is designed to control a current intensity of an electrical current flowing from the feed unit into the at least one intermediate circuit capacitor as a function of a control signal, - wherein the frequency converter has a measuring facility (60, 62, 68, B) for acquiring measurement values for at least one measurement variable (U 48) dependent upon an operating state of the frequency converter, and also has a control facility, which is designed to generate the control signal as a function of the acquired measurement values, and - wherein the intermediate circuit has a commutation capacitor on the feed side of the semiconductor switch, i.e. in the part of the intermediate circuit which has a permanent electrical connection to the feed unit, through which commutation capacitor a commutation capacitance for the feed unit is supplied, characterised by the steps: - coupling the feed unit to the network; - in a pre-charging phase, charging the intermediate circuit capacitor with electrical energy from the network and, in doing so, controlling the current intensity of the charging current of the intermediate circuit capacitor by generating the control signal at a control input of the semiconductor switch by means of the control facility, - wherein, in the frequency converter, an induction voltage arising when switching components of the feed unit is kept below a voltage value which it critical for the functionality of the frequency converter by means of the commutation capacitance and - wherein the semiconductor switch, in the pre-charging phase, is operated to control the current intensity as a controllable current source and, in doing so, a current intensity of a load current flowing through the semiconductor switch is controlled by adjusting the control signal. - wherein the frequency converter has a feed unit and a converter, which are interconnected via a DC voltage intermediate circuit, in which an intermediate circuit capacitance is supplied by at least one intermediate circuit capacitor, - wherein the network-side feed unit is designed to convert between a network AC voltage and a DC voltage (U 48), which is supplied in the intermediate circuit, and the converter is designed to convert between the DC voltage (U 48) and an AC voltage for the electrical machine, - wherein the intermediate circuit has a semiconductor switch, which is designed to control a current intensity of an electrical current flowing from the feed unit into the at least one intermediate circuit capacitor as a function of a control signal, - wherein the frequency converter has a measuring facility (60, 62, 68, B) for acquiring measurement values for at least one measurement variable (U 48) dependent upon an operating state of the frequency converter, and also has a control facility, which is designed to generate the control signal as a function of the acquired measurement values, and - wherein the intermediate circuit has a commutation capacitor on the feed side of the semiconductor switch, i.e. in the part of the intermediate circuit which has a permanent electrical connection to the feed unit, through which commutation capacitor a commutation capacitance for the feed unit is supplied, - coupling the feed unit to the network; - in a pre-charging phase, charging the intermediate circuit capacitor with electrical energy from the network and, in doing so, controlling the current intensity of the charging current of the intermediate circuit capacitor by generating the control signal at a control input of the semiconductor switch by means of the control facility, - wherein, in the frequency converter, an induction voltage arising when switching components of the feed unit is kept below a voltage value which it critical for the functionality of the frequency converter by means of the commutation capacitance and - wherein the semiconductor switch, in the pre-charging phase, is operated to control the current intensity as a controllable current source and, in doing so, a current intensity of a load current flowing through the semiconductor switch is controlled by adjusting the control signal.