Grid Tie Inverter MOSFET Replacement part IRFP25N50N

[tozoysa]

Hello,

I've noticed my grid tie inverter has dead short in one of the MOSFETs when it stopped working. I couldn't find any reference to this part on the internet or any other online store.

I believe this could be N-Channel MOSFET but not sure whether it is possible to replace with any similar N-Channel MOSFET. I've attached pictures for your reference and any help is greatly appreciated.

Thanks in advance.

Part IRFP25N50N:

 

[GPG]

What is the link DC voltage? You could verify the N/P question by checking the other FET Are they in parallel?

 

[tozoysa]

Thanks @GPG for the prompt response. Actually at first this inverter had blown AC fuse, So i replaced the fuse and it blew again. Then only i found this MOSFET is dead short. I checked these 4 MOSFETs and yes those are in parallel(2x2). And about the DC voltage i presume you are asking the MOSFET Gate voltage? If so how can i measure gate voltage?, is it safe to connect to AC without that MOSFET?

Thanks again!

 

[hevans1944]

It's a power MOSFET rated 200 V at 30A. Might be imported from Thailand. Found the datasheet here.

 

[tozoysa]

Thanks @hevans1944. Actually i landed above page before, But my problem was the voltage rating. The country where i live has household voltage range 230/250 V. So above MOSFET is not a substitute for my unit, isn't it?

 

[GPG]

DC voltage i presume you are asking the MOSFET Gate voltage?

No. http://solar.smps.us/grid-tie-inverter-schematic.html The link voltage is the voltage out of the first converter.

 

[hevans1944]

Thanks @hevans1944. Actually i landed above page before, But my problem was the voltage rating. The country where i live has household voltage range 230/250 V. So above MOSFET is not a substitute for my unit, isn't it?

Well, it is what it is, and what you removed from the inverter. It could be a bad inverter design, but we don't have a schematic to see what is going on. Read the information at the website link provided by @GPG to get an idea of what is going on, but realize the "schematics" are conceptional not actual circuits. The MOSFETs in that description boost the solar array DC voltage to a higher level AC waveform not necessarily related to the power line frequency. After applying that waveform to a transformer it is rectified and that output is applied to IGBTs that are pulse-width modulated to synthesize the AC output waveform. The resulting output line voltage has no direct relationship to the MOSFET voltages.

Sometimes manufacturers cut corners and use a marginally acceptable part in place of the part the original design calls for. Or the original design could be marginal. Either way, I would look for a MOSFET with a higher voltage rating capable of 30 A current and replace all four of them. The original equipment part is not only hard to find but probably a lot more expensive than currently available MOSFETs of similar or better specifications.

If you can find the schematic for your inverter, please post it here for possible guidance in selecting a substitute for the original MOSFETs.

Hop

 

[tozoysa]

Thanks @hevans1944 and @GPG, Since this is a Chinese product i couldn't find the schematic for this inverter, But I have already ordered the above substitute part and i'm gonna try that. I'll let you guys know how it goes.

Thanks again!

 

[cjdelphi]

Even though it's rated 200v i'm sure it will cope with 220/240v

Certainly not recommended, but obviously this unit worked with them (may explain why it failed! Buy a couple as the next one to fail might be around the corner)