Abstract: The shape of the rising and falling edges of AC output voltage pulses of a PWM frequency converter is controlled by reducing a speed of change, and a height, of the AC output voltage pulse. The PWM frequency converter rectifies the alternating voltage of a supply network into a DC voltage which is filtered. A load bridge having power semiconductor phase switches forms an AC output voltage from the DC voltage for controlling the load. An average speed of voltage change of AC output voltage pulses is set using a phase switch to control at least one power component to be conductive and non-conductive in turn for a period of at least about one microsecond to change a pulse edge of the AC output voltage pulses into at least one micropulse, the width of which is controlled to increase towards a final state of the phase switch.