Amplitude control and harmonic reduction may not be compatible. For
example, establishing at 30 to eliminate the third harmonic fixes the amplitude
of the output fundamental frequency at V1 (4Vdc/
) cos 30 1.1Vdc and
removes further controllability. To control both amplitude and harmonics using
this switching scheme, it is necessary to be able to control the dc input voltage to
the inverter. A dc-dc converter (Chap. 6 and 7) placed between the dc source and the
inverter can provide a controlled dc input to the inverter.