hi Binu,
u should be able to simulate the power consumption of your device by using Orcad (it looks like this is the software you use). i see this one phase of a BLDC motor, it looks like you have an exotic topology. i'd like to see the whole thing, with explination of how it works, some time
to analyze the power dissipation realize that MOSFETs have two types of power loss. switching loss & conduction loss. usually only one term is calculated (the dominant) term and the other term is considered insignificant.
i recall from memory (i.e. u should double check this)
1) switching loss = (Eon + Eoff)*Fsw ; where Eon/off is the energy to turn ON or OFF the device, usually stated in the datasheet.
2) conduction loss = (Ids)^2 * Rdson
now u must determine for your application which is the dominant term. for motor drives usually it is conduction, but a simple calculation will tell you.
the power loss in your motor is primarily from conduction loss. (I_line_rms)^2 * R_armature ; per phase.
yes your circuit will carry double the current because you are paralleling mosfets. but remember that with engineering you never get a free lunch. you will see a tradeoff with efficiency as your MOSFETs will ring/oscillate in that configuration. orcad is not likely to pick this up because it depends greatly on parasitic capacitance & the quality of your gate drive.
also, do not expect your mosfets to share current 50% each. it can drift as much as 75% in one and 25% in other.
Mr.Cool