Producing a motor voltage for a switch drive

A power converter for producing a motor voltage for an electric motor of a drive of an electrical switch, the power converter comprising:

• a first power converter unit configured to produce a DC link direct voltage from a supply voltage;
• a measuring unit configured to continually measure an actual value of the DC link direct voltage;
• a second power converter unit configured to produce the motor voltage by pulse-width modulation of the DC link direct voltage;
• and
• a control unit configured:
• to store a specifiable tolerance range for a change in the DC link direct voltage,
• after a first measurement of the actual value, to store the actual value in a voltage variable,
• after each additional measurement of the actual value, to check whether a deviation of the actual value from the value stored in the voltage variable lies within the tolerance range, and to store the actual value in the voltage variable when the deviation of the actual value from the value stored in the voltage variable lies outside of the tolerance range;
• and
• after each storage of an actual value in the voltage variable, to calculate a duty cycle, being dependent on the actual value, of the pulse-width modulation and to control the pulse-width modulation with the duty cycle.