Siemens 6SR41 series - Figure 3-2 Schematic of a Typical Power Cell; Figure 3-3 Waveforms for Phase a

Theory
3.2 The Power Circuitry
Product User Manual
Operating Instructions, Version AE 12/2009, A5E01454341C
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Figure 3-2 Schematic of a Typical Power Cell
Finally, the reference signal is compared with the third carrier (shifted 240 degrees) and its
inverse to generate control signals L3 and R3 for the transistors in cell A3. The output
waveform of cell A3 is shown as A3.
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Figure 3-3 Waveforms for Phase A
The sum of the output voltages from cells A1, A2 and A3 produces the A-to-neutral output
voltage of the drive, shown in Figure "Waveforms for Phase A" as AN. There are 7 distinct
voltage levels. Note that this voltage is defined between terminal A and the floating neutral
inside the drive, not the motor neutral.