**Subject :**Power Electronics

**Unit :**DC to AC Converters

## Generation Of 3-Phase Sine-PWM Waveform

**Generation Of 3-Phase Sine-PWM Waveform:**

*Fig: Three phase PWM inverter*

*Fig: Sine-PWM waveforms for single-phase H-Bridge inverter*

- A three-phase inverter, as discussed in Lessons 36, can be used to output a three-phase sine modulated pole-voltage pulses.
- Switches in each of the three poles of the inverter are individually controlled as per the technique discussed in the previous section.
- For a balanced three-phase output voltage from the inverter poles, the three sinusoidal modulating signals (one for each pole) must also be balanced three-phase signals.
- The carrier waveform for all the three poles may remain identical. The fundamental components of individual pole output voltages (for 0<<1) will thus be proportional to the corresponding modulating signals.
- For m = 1, the rms magnitude of line-to-line voltage (fundamental component) output by the inverter will be equal to

**.**

- A typical line voltage waveform (difference of two pole voltage waveforms) will appear similar to the line voltage waveform (V).