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Mismatch in power balance with Maxwell circuit editor

chetank
Аватар пользователя chetank

I am simulating switched reluctance machine of custom geometry ( not generated by RMXprt) with Maxwell circuit editor using external windings. I got the desired power level for the desigened motor but there is mismatch of power between input and shaft.

Motion setup is for constant current means mechanical transients are unchecked. 

The motor shaft power is 15 kW average but even accounting all losses like copper, core , solid loss and switching losses of circuit elements , there is excess of 3kW of input power. 

Shaft power 15 kW

Losses all 1.2kW

Input power 19.2kW 

Anybody explain this behaviour to me?

Klyavlin
Аватар пользователя Klyavlin

Hello. My advice is use simple design in Rmxprt and try to obtain the right power balance in Maxwell. It'll be very useful.

chetank
Аватар пользователя chetank

Thnaks for your reply.

The motor geometry is not standard and hence not availbale in RMxprt. However drive topology is same as RMxprt which is asymetric configuration for SRM.

How power balance is not met if geometry is not standard one?

Is it normal behaviour of Maxwell circuit editor?

All parameters are fine but due to unaccounted power loss of 3kW, efficiency is lower than actual.

Note: I have accounted switching losses also.

 

Klyavlin
Аватар пользователя Klyavlin

I understand your concern over the strange results. I advise you to take any SRM machine and practice with it. If you do everything right, then the power balance in Maxwell will approximately correspond to the results in RMxprt.

chetank
Аватар пользователя chetank

You did not understand my problem due to my inadequate explanation friend. Let me explain properly.

The DRM that I am simulating is non conventional called as " short flux SRM" whose template is not available in RMxprt. Hence I imported geometry of the machine and solved the 2D transient model. The windings are set to external and supplied with standard RMxprt SRM converter. The defined motion set up is without mechanical transients.The  solution matches with the analytical results nicely. The problem is in power balance. 

Ideally 

Input drive power= Shaft power+ copper loss + core loss+ switching loss. 

Switching loss is calculated by using switch current and voltage in Maxwell circuit editor.

However there is unaccounted input power of 3kW . Output power is 15kW. This is huge variation. The problem persists even I disabled core loss settings. What could be probable reason for this?

I observed that power balance between drive input and electromechanical power developed is fine. The mismatch occurs in shaft power and input power.

Klyavlin
Аватар пользователя Klyavlin

I understood you from the very beginning. I didn’t see your model and suggested to train in the power balance on a typical SRM motor in an expert

chetank
Аватар пользователя chetank

It was averaging error over a period!! My bad..Now power balance is fine. Thank you!!

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