Page 362 - Power Electronics Handbook

352 D.C. link frequency changers

13.43. The high-frequency triangular wave is compared with a low-
frequency square, triangular or sine waveform, the inverter frequency
being determined by the frequency of this low-frequency wave and the
magnitude of the output voltage by its amplitude relative to the reference
high-frequency wave. The remainder of the circuit, with sequencer, driver
and current or voltage feedback, is as before.
Staggered phase carrier cancellation is illustrated in Figure 13.68. The
two high-frequency carrier waveforms are phase shifted by 180" before
being modulated by the low-frequency waveform and then compared, as in
Figure 13.44. The subsequent control stages are then as before.