## Electronics

#### Ansys Maxwell Transformer Transient Simulation

• mitche61
Subscriber

I'm modeling the transformer shown below, with an applied voltage of 600*cos(2*pi*100000*time). I have assigned the primary winding resistance to 0.01uOhms and the secondary winding resistance to 10kOhms, and would expect the secondary induced voltage to be 600*(10/3) = 180V. When I run a transient simulation, however, this is not the case, and my results are are shown below. The voltages are extremely high and the secondary winding induced voltages are actually higher than the primary. I am using ferrite for the core, copper for the windings, and have created a region of air around the transformer. I also have length-based assigned mesh operations for the primary and secondary windings, with the max length set at 11mm. Any help would be greatly appreciated!

• Navya C
Ansys Employee
Hi,nAs per the data provided by you. nYour primary winding turns (N1) = 3 and you are exciting it with a voltage of 600*cos(2*pi*100000*time)nSecondary winding turns(N2) = 10nThen, assuming an Ideal transformer case, secondary voltage = (primary voltage)*(N2/N1) = 600*(10/3) = 2000VnSince your secondary turns are more than 3 times primary turns you will have more than 3 times voltage on secondary winding terminals ideally.nSo, what I see on the graph seems to be correct which is more than 1600 V on secondary.nnRegardsnNavyann
• AndyJP
Subscriber
I guess, there's a typo. The author sees 1.8kV (or 1.5?) on the plot and types/copypastes something (180V) by mistake, probably, or there is no sense to that.kVnSo, the question is probably, where those lost 200-500V go?n
• mitche61
Subscriber
Thank you for the quick responses! My primary windings (N1) = 10 and the secondary windings (N2) = 3, which is why I initially said that I expected the secondary voltage to be 600*(10/3) = 180 V from the ideal transformer relationship V2/V1 = N2/N1. I've double checked my design and winding 1 is assigned to the 10 turn coil and winding 2 is assigned to the 3 turn coil, so I'm really not sure why the voltage is being stepped up instead of stepped down.n
• AndyJP
Subscriber
check your ports.nuse equal resistance.n
• mitche61
Subscriber
Thank you again for your response. When I use equal resistances on the windings, the voltages make sense, however the secondary induced voltage is phase shifted from the primary induced voltage. I used 6mOhms for each of the windings, as this is the measured resistance of the coils I am trying to simulate. Is there another resistance value I can calculate to use so that the voltages are not phase shifted?n
• mitche61
Subscriber
I think it might be related to the mesh on the coils if I had to guess, when I simulate a nearly identical transformer but with pre-defined user primitive polygon helix I don't run into these weird phase shifting issues. Could it be something else with the design on the coils?n
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