possible
voltage levels. As more dc sources and H bridges are added, the total output voltage has more steps, producing a staircase waveform that more closely
approaches a sinusoid. For a five-source system as shown in Fig. 8-11, there are
11 possible output voltage levels, as illustrated in Fig. 8-12.
The Fourier series for a staircase waveform such as that in Fig 8-12 for k separate dc sources each equal to