9.4. Converter Topologies and Modulation Techniques
The back-to-back (AC/DC/AC) converters form the grid-side converter (inverter) and the generator-side converter (rectifier). The converter transforms the DC input voltage into a symmetrical AC output voltage of desired magnitude and frequency. The output voltage can be constant or variable at a fixed or variable frequency. A variable output voltage can be obtained by varying the input DC voltage and maintaining the gain of converters constant. The output voltage waveforms of ideal converters should be sinusoidal. But, the waveforms of realistic converters are nonsinusoidal and contain certain harmonics [57,58].
9.4.1. Two-Level Topology
The circuit diagram of a three-phase inverter is shown in ...