Ideal Switch implementation in Simulink

Hi,

I am using MATLAB R2012b. I am attaching the image so that you can see what I am complaining about. The pulse generator generates pulses with 50% duty cycle and amplitude 1 and drives the gate of ideal switch, which means that the voltage across the resistor should also switch exactly at the rate of switching of the switch. I have set the frequency of AC current source to 0 Hz so that it simulates a DC source. However, the voltage measurement across the resistor shows a constant voltage drop of 1V (when phase is 90), 0V (when phase is 0) or -1V (if i change the phase of the AC current source to -90)when in reality it should switch between 0 and 1V.

Please help me resolve this. Regards, Sharjeel.

[Tony Castillo]

Hi dear friend, do you remenber how to solve that problem?, because in my system is presented the same issue. Thanks in advance

Answer 1

[Sabin]

As per the attached circuit this is the expected behavior as a current is forced into the circuit. The voltage across the resistor I expect to be constant in this situation (and current as well).

The ideal current source will force the specified current no matter what. The switch voltage will increase quite a bit (depending on the on resistance) and will be pulse like, but this will not prevent the current set by the ideal current source. A switch can not really go to zero conductance but even if this would be physically possible, the current source would produce such high voltage that the switch will conduct because of the electric arc.