Hello Taimur,
right now your converter is being controlled by an open loop pulse generator that doesn't allow you to shift the phase of the pulses like you need to. You could generate your own carrier signal where you can specify the phase. Alternatively, you could add a controlled delay like this to control phase: https://www.mathworks.com/help/simulink/slref/tuen-phase-delay-on-pulse-generator-during-simulation.html
The first can be more computationally efficient, but the second will be easier.
Regards,
Joel
