How can I connect the mosfet driver?
That kind of "bootstrap diode and capacitor" gate driver uses a capacitor that gets floated up and connected between the gate-emitter of the high-side MOSFET/IGBT to provide the floating gate drive. But there is a catch...

That bootstrap  capacitor drains and need to be recharged periodically. It is normally used a half-bridge circuit where complimentary PWM is occuring (or the low-side transistor is turning on very regularly). This is a half-bridge by the way:



Take from: http://www.irf.com/electronics/topology-fundamentals

This connects the negative terminal of the bootstrap capacitor to GND and allows current to flow through the from +V through the diode through the cap to GND and recharge it. The diode stops the bootstrap cap from emptying back into the supply when it gets floated up.




Taken from: http://www.ti.com/lit/pdf/slua887

This means two things for a bootstrap capacitor and diode high-side gate drive circuit:


a bootstrap high-side gate drive cannot achieve 100% duty cycle.
you need a low-side switch to recharge the capacitor (or some extra fancy charge pump circuitry)


Your circuit might not need 100% dutty cycle (although it might seem like you do depending on how long it takes to charge up your capacitor) but the definite thing is that your circuit has no low-side transistor to recharge the boostrap cap. That means you need to use a more expensive method. The most straightforward is just to replace the bootstrap capacitor with an isolated voltage regulator. You can also remove the bootstrap diode since it is no longer needed.



Also, you mentioned PSIM. Did you make that gate-driver block yourself? It's not correct inside (or at least, it's very crude and would not work very well at all in real life since the pull-up resistor slows things down a lot). In a simulation you can maybe just use a floating supply straight across gate-emitter of IGBT1. In real life you could technically do that too. It's just more expensive