**Sinusoidal Pulse Width Modulation (SPWM)**

Apply multiple gate signals to the IGBTs T1, T2 in positive half-cycle and T3, T4 in negative half-cycle. The gate signals for T1, T2 are generated by comparing the high frequency (f_{car}) triangular carrier signal v_{car1} with sine control signal v_{c1} of frequency f_{o}. Similarly, the gate signals for T3, T4 are generated by comparing the v_{car2} (=v_{car1}) with sine control signal v_{c2} = -v_{c1} of frequency f_{o}. The peak magnitude of control sine signal controls the modulation index m_{a} which in turn controls the rms output voltage.

Observe the waveforms across each element of the power circuit with R and RL loads.

The output voltage and current can be observed for different values of R_{o}, L_{o}, V_{dc}, V_{c1}, V_{c2}, m_{a}, m_{f} or f_{o}.

**Main Circuit Diagram**

**Circuit Diagram With Voltmeters And Ammeters At Various Points**

**Waveforms**

__For R Load__

R = 10 Ω

__For RL Load.__

R = 1 Ω, L = 10 mH