The present invention relates to a method of generating various alternating current waveforms, at power level. The AC mains power supply is rectified, processed by various circuits, controlled by a control unit and inverted as required at the output. This method may be employed with converter isolation from the mains. It is also possible to employ the system so that the input current is sinusoidal and the power factor of the converter is unity. The present invention produces preferably the sinusoidal output waveform with fundamental component at the desired frequency, where this waveform is produced employing a DC bus from which output voltage with the fundamental component at the desired shape and frequency is obtained using pulse width modulation techniques. The output stage is simply an inverter which inverts this waveform at zero-crossings of the rectified waveform to obtain an AC output.