TIDM-HV-1PH-DCAC: Overcurrent trip during grid connected mode

Hannah Aaronson

I am using this module in grid connected mode, without any modifications to the hardware or software. Build 1 and Build 2: DC Check work just fine. When I move to Build 2: AC Check, I connect the relays, but whenever I select rlyConnect to 1, it immediately goes into Overcurrent trip mode and the relays switch off. This happens no matter if invloRef is set to 0.01 or 0, and with a DC Bus Voltage of 300 V. I don't have access to an AC power supply so I'm just plugging the AC side directly into an outlet. Do you have any advice?

Thank you!

over 5 years ago

0 Manish Bhardwaj over 5 years ago

TI__Mastermind 43730 points

Did you make the HW changes as instructed in the user guide for the grid connected mode?

se note in 3.1.1 http://www.ti.com/lit/ug/tidub21c/tidub21c.pdf

0 Hannah Aaronson over 5 years ago in reply to Manish Bhardwaj

Prodigy 70 points

Hi Manish,

Yes I swapped C1 for the 1uF cap and added L2 and L2N.

0 Manish Bhardwaj over 5 years ago in reply to Hannah Aaronson

TI__Mastermind 43730 points

You are checking this with 120Vrms grid ?

0 Hannah Aaronson over 5 years ago in reply to Manish Bhardwaj

Prodigy 70 points

Yes I am in the US, with 120 Vrms grid.

0 Manish Bhardwaj over 5 years ago in reply to Hannah Aaronson

TI__Mastermind 43730 points

DC voltage 300V may be an issue as well. we only tested with 380V DC bus

0 Hannah Aaronson over 5 years ago in reply to Manish Bhardwaj

Prodigy 70 points

Hi Manish,

Apologies for the delayed response. I just tried it this morning using two power supplies in series, giving a DC voltage of 275 V, and still have an over current trip.

0 Hannah Aaronson over 5 years ago in reply to Hannah Aaronson

Prodigy 70 points

Hi Manish,

I realized I have a few typos in this thread. First, I tried with input DC voltage 375 V (not 275 V). I connect the relays and everything is fine. I set invIoRef = .01. Then, when I set clearInvTrip = 1, the overcurrent trip happens immediately. I have direct 110 Vrms/60Hz grid connection on the AC side.

Do you have any suggestions? I have been quite stuck on this issue for a few weeks.

0 Manish Bhardwaj over 5 years ago in reply to Hannah Aaronson

TI__Mastermind 43730 points

Hannah,

If the final build is not working, the only way to debug the issue is to follow the incremental build method as it offers some ideas as to where the root cause of the issue may be.

For example in this case, Build Level 2—Close Current Loop: AC Check,

If you are not able to slowly increase the AC voltage, checking in a black box manner will not be feasible.

The only thing i could suggest is you have to reduce the KDC from 0.2 to 0.1 and see, as that can improve the GM slightly.

0 Hannah Aaronson over 5 years ago in reply to Manish Bhardwaj

Prodigy 70 points

Hi Manish,

Our final goal with the module is to add an outer voltage control loop such that an AC input voltage would output high voltage on the DC bus. Although we were never able to get the module to work with a DC power supply on the DC bus side as per the user guide, we were able to successfully add this outer voltage loop and bidirectionally send power, so getting it to work with the DC power supply is no longer necessary.

Thank you for the help!

Hannah

0 Manish Bhardwaj over 5 years ago in reply to Hannah Aaronson

TI__Mastermind 43730 points

Hannah,

Thanks for the update, it is great to know that you were able to operare this as a rectifier with your code, congrats!

I do apologie the out of box for the grid connected was not what you expected, honestly the grid feed inverters are tricky.

I am glad everything worked out in the end.

-Manish

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TIDM-HV-1PH-DCAC: Overcurrent trip during grid connected mode