CCS/TMDSSOLARUINVKIT: C2000 micro inverter questions

Ming-Hung Chen

Part Number: TMDSSOLARUINVKIT

Tool/software: Code Composer Studio

Hi,

On page 12 of tidu405.pdf (UG_SOLAR_Micro_Inverter), may I know the calculation on how to get the equation (15) as follows? Thanks.

over 7 years ago

0 Manish Bhardwaj over 7 years ago

TI__Mastermind 43730 points

We have some more details here

ieeexplore.ieee.org/.../

that;s the best i can do, I am not allowed to share matlab scripts on the forum. as they were not release part of original software.

0 Ming-Hung Chen over 7 years ago in reply to Manish Bhardwaj

Intellectual 390 points

Hi Manish,
I see. I will read the paper first. By the way, may I know Zc, Zi, and Zg you built in the model? After checking the specification of each part, here are what I used.
Zc: Rf=0.26 Ohm, Cf=0.22uF;
Zi: Ri=0.93 Ohm, Li=7.2mH;
Zg: Rg=0.13 Ohm, Lg=470uH;
I would like to know those parameters so I may have the same ground with you to derive the transfer function of 3P3Z controller. Thanks.

0 Manish Bhardwaj over 7 years ago in reply to Ming-Hung Chen

TI__Mastermind 43730 points

Zc: Rf=0.26 Ohm, Cf=0.22uF;
Zi: Ri=0.93 Ohm, Li=7.2mH;
Zg: Rg=0.13 Ohm, Lg=470uH;

looks good to me. I might have also checked for Li=5mH, as the inductance varies with current.

0 Ming-Hung Chen over 7 years ago in reply to Manish Bhardwaj

Intellectual 390 points

Hi Manish,

Zc: Rf=0.26 Ohm, Cf=0.22uF;
Zi: Ri=0.93 Ohm, Li=7.2mH;
Zg: Rg=0.13 Ohm, Lg=470uH;

They are used on TMDSSOLARUINVKIT so that's why I asked. Actually, Zi: Ri=0.93 Ohm, Li=7.2mH is too big so we are trying to reduce Zi. What is the formula for 3P3Z controller if Li is changed?

0 Manish Bhardwaj over 7 years ago in reply to Ming-Hung Chen

TI__Mastermind 43730 points

we did use 7.2mH inductor, Though i am not sure for controller design i might have used 5mH as the eff inductance when the current is flowing is lower, its only 7.2mH close to the zero current.

The controller is the same as you have mentioned earlier.

0 Ming-Hung Chen over 7 years ago in reply to Manish Bhardwaj

Intellectual 390 points

Hi Manish,
Do you mean only 7.2mH close to the zero current when "inv_Iset" is set to zero under built 2? I don't really catch your point.

0 Manish Bhardwaj over 7 years ago in reply to Ming-Hung Chen

TI__Mastermind 43730 points

Inductance is typically the highest at zero current and as you draw more current through the inductor it typically drops. The drop depends on the material used for the inductance design.

So if you use 7.2mH for design, you may try to push too much gain for a desired bandwidth.

Which in reality when current is flowing, is ~5mH. Hence it may be more safe and accurate to design with 5mH and take some hit during low current flow.

This type of intution you get with exprience and trial and error and also is not part of the support I can provide through this forum.

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CCS/TMDSSOLARUINVKIT: C2000 micro inverter questions