Voltage Control of Three Phase DC-AC Inverter using Sinusoidal PWM

The generation of gating signals for a three phase DC-AC inverter with sine PWM are shown in Figure 8 . There are three sinusoidal reference waves (v_ra , v_rb , v_rc) each shifted by 120° . A triangular carrier wave is compared with the reference signals to produce the gating signals. Comparing the carrier signal v_cr with the reference phases v_ra , v_rb , v_rc produces the signals for gates 1, 2 and 3 (g₁, g₂, g₃). The instantaneous line-to-line output voltage is

                                                                                                       (17)

The output voltage is generated by eliminating the condition that two switching devices in the same arm cannot conduct at the same time.

 

Figure 8: Voltage and Current waveforms for three phase Sinusoidal PWM

 

Suggested Reading:

[1] M. H. Rashid, Power Electronics: Circuits, Devices and Applications , 3 rd edition, Pearson, 2004

[2] V. R. Moorthi, Power Electronics: Devices, Circuits and Industrial Applications , Oxford University Press, 2007