SpeedFit Design Simulator ActivePower Confusion

BayResearcher

Hi,

I have a confusion about power ratings of the simulation. So, i am not sure about the power losses of the module. My input parameters in SpeedFit are the picture below.

Here, it shows 320A RMS output current.

But here, it shows 268kW actual power.

The actual power must be 275000VAx0.78=214500W. So, i am not sure about the extracted losses that they are true.

What is the reason? I will be appreciated if you help me.

Thank you. Regards...

TBhatia

Hello, thank you for your message. A member of our technical team is looking into your questions and we will respond shortly. 

ZMiller

Hi,

The simulation assumes that the power you specify is the desired output power of the system, and the apparent power of the system is calculated as S = P/pf. I hope that clears things up.

Thanks,

Zack

BayResearcher

Hi,

What i understand that the Speedfit calculated the losses according to 214 kW actual power ( 275000VAx0.78=214500W). is it right?

Thank you.

ZMiller

Hi,

Not exactly. Speedfit sees the input of 275000 VA, assumes you want that as the output power so P = 275000W and S = (275000/0.78) = ~352500. I hope that makes sense.

Thanks,

Zack

BayResearcher

Hi Zack,

First of all thank you for your answer. But i have questions in response to your answer.

1-

The unit (VA) is Apparent Power's unit which is denoted by S. So, why Speedfit sees the Rated Output Power So as an Actual Power P. It's not logical. There is also "Power factor" that Actual Power can be extracted by the formula of P=S.cos(fi).

2- If Rated Output Power is actual power, why RMS current is 320A. It has to be nearly 415A RMS.

Will be waiting for your answer.

Kind regards.

ZMiller

Hi,

I understand the confusion that the current nomenclature is generating and I agree with you. This issue appears to be unique to this topology, but I'm working on validating that. The RMS current is being calculated outside of the simulation from your designated inputs and it should be 415A in this instance (assuming you want Po = 275kW). I'll work to turn over a fix that will clarify these issues and you can probably expect to see this within the next few days.

Thanks,

Zack

BayResearcher

Hi,

Actually i need the losses @214kW, 320A (S: 275000 VA, cos(fi): 0.78, Vo: 495 VAC (RMS) )

Thanks.

ZMiller

Hi,

I recommend running the simulation with all of your parameters as they are but adjusting the "So" parameter to your desired output power for now. It will take some time before the model changes can be uploaded to the website to reflect the correction in the power factor calculation. Note that this will calculate the RMS current in the device selection stage incorrectly, so you'll need to verify that independently for now.

I hope this helps.

Thanks,

Zack

TBhatia

Hi, I hope that this answered your question. I will close this discussion for now but if you have a follow up question, please "Start a New Discussion" and we would be glad to support you further.