![does multisim 12 handle transistors and mosfets does multisim 12 handle transistors and mosfets](https://i.stack.imgur.com/IbQYd.png)
- #Does multisim 12 handle transistors and mosfets how to#
- #Does multisim 12 handle transistors and mosfets driver#
- #Does multisim 12 handle transistors and mosfets skin#
- #Does multisim 12 handle transistors and mosfets code#
This post will hopefully allow me to re-enforce what I learned and maybe teach others about these two subjects as well. I had to do a bit of research before being able to answer either of those questions.
#Does multisim 12 handle transistors and mosfets how to#
I knew that DTI was necessary I just had no idea how much was needed or how to go about implementing it.
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DTI is guaranteed off time to ensure that no overlap happens. This can happen because switching on and off transistors just like anything else is not instantaneous and some overlap may occur. The main goal of DTI is to avoid a short circuit from the high side of the DC Bus to ground through the two transistors that control a single phase.
#Does multisim 12 handle transistors and mosfets skin#
I originally was just under the naive impression that there was one standard way to perform the functionality, and was no so surprised to find that "there is more than one way to skin a cat." The second area of knowledge that I did not know too much about, and was only vaguely aware of is the practice of dead-time insertion (DTI). There are 4 main variants of PWM control schemes for a 3 phase BLDC controller. The first of the two being the PWM control scheme.
#Does multisim 12 handle transistors and mosfets code#
There were two fundamental gaps in my knowledge on BLDC control that I did not know I was lacking in until I attempted to start writing the code to control a motor. This meant that all I really needed to do to get the motor spinning was fire up some pwm signals on my micro and done, right!? Well I was wrong. In my last post on this project I had successfully designed and put together my physical motor driver. The load values look more like an academic execise than some realistic load.So as is often the case I vastly overestimated my knowledge on a few subjects. Use resistive loads or simple capacitors in place of the gates.
#Does multisim 12 handle transistors and mosfets driver#
For example to validate the bootstrap capacitor model just the gate driver and capacitor with the transistors removed. When a circuit does not work in simulation as you expect, it can be helpful to model one section at a time. Things like calculating the bootstrap capacitor for a particular operating frequency need to be done manually to select a value appropriate to the requirements before simulation. Often they are not very good at modelling the behavior of poor designs. Simulations are design tools intended to verify that a preliminary design works as expected. It might also be due to the bootstrap capacitor being too small. Stair-like increase in current in the inductor might be due to the fact the the resonant frequency of the L1 C2 circuit is 159 kHz and you are driving it at 500 Hz. 0.2 uF is probably OK for 50 kHz but may be small for 500 Hz. I do not have time to look up the data sheets and calculate the required currents. The bootstrap capacitor might be small for a 500 Hz pulse rate. I see a few things which might be factors. ** CJO (diode), CJE, CJC, CJS (BJT), CDG, CGS (JFET) ** Raise ITL1=500 (DC OP iterations limit) ** RS (diode), RE, RC (BJT), RD, RS (FET) ** semiconductor models should have non-zero resistances *** will have minimal effect when added to circuit. ** set GMIN = 1/Rp where Rp is parasitic resistance which This is what I found helpful from one of them: There are books written on how to deal with SPICE convergence problems. If you do not need to model the detailed behavior of the driver, using pulsed sources with rise/fall times as long as possible without changing the behavior of the MOSFETs might be a better choice.ģ. I wrote my own model using transmission lines for delay and non-linear dependent sources with tanh functions rather than hard switches.Ģ. This is because the switching action introduces a strong non-linearity into the model. MOSFET driver models often use switches and these can lead to convergence problems. I do not have Multisim so I cannot see your circuits but have some general observations.ġ.