How can I simulate the response from starting and terminating a synchronous motor using simpowersystem?

Hi,

I am trying to simulate the response of a synchronous motor starting up, then maintaining steady-state and finally terminating. What are the inputs or parameters required.

I generated a trapezium signal for the mechanical input port(Pm) but the output rotor speed always begins at 1pu, instead of 0. I tried using initial speed deviation(dw%) of -100, but it causes an integration error.

What are the inputs or parameters required?

Would greatly appreciate any help.