Both positive and negative converters can generate voltages at either polarity, but the positive converter can only supply positive current and the negative converter can only supply negative current. Thus, the cycloconverter can
operate in four quadrants: (+v, +i) and (-v, -i) rectification modes and (+v, -i) and (-v, +i)
inversion modes. The modulation of the output voltage and the fundamental output voltage are
shown in Fig. 6. Note that ais sinusoidally modulated over the cycle to generate a harmonically
optimum output voltage