LM5148-Q1: Solar - PV optimizer Design & Development -Power Topology Selection

Nitesh Modi

Part Number: LM5148-Q1
Other Parts Discussed in Thread: LM5175, LM5176

Tool/software:

Hi there,

Currently I am working on development of MPPT based PV optimizer for solar power optimisation,

The Power level of Power optimizer is 700Wp [Voc= 52V, ISC = 15.5A.( Vmpp = 50V, Impp=14A)] Which power topology is more suitable in non-isolated topology area?

With lot of literature study, I have come across buck, buck-boost, cuk.

Which is the best suitable power topology, that I should prefer as far as the solar domain concerns.

In in case of buck-boost (which one to select buck-boost or cuk)?

Thanks in Advance!!!

2 days ago

0 Timothy Hegarty 2 days ago

TI__Guru 52122 points

Hi Nitesh,

What is the required output voltage? And what is the Vin range (as Vmpp will vary with irradiance, temperature, etc.)? This determines whether you need a buck or a buck-boost solution.

For a buck-boost regulator at 700W, take a look at the LM5175/6/7 family.

Regards,

Tim

0 Nitesh Modi 1 day ago

Prodigy 10 points

Hello Tim,

The range of Vmpp is 20V-50V. And output voltage is in range of 20V-63V.

At for 700W power rating which topology is more efficient bock-boost or cuk in terms of performce, cost, efficiency ?

0 Timothy Hegarty 1 day ago in reply to Nitesh Modi

TI__Guru 52122 points

Nitesh,

Take a look at the 4-switch non-inverting buck boost - LM5175, LM5176, etc. This is the recommended circuit at this power level.

Note that conventional buck-boost and Cuk designs are inverting, producing a negative output voltage. The SEPIC and 2-switch buck-boost are non-inverting but suitable at lower powers.

Regards,

Tim

0 Nitesh Modi 1 day ago

Prodigy 10 points

Tim,

Non inverting is not a concern for me.even thogh if Asic is also not a concern for me. I can go with digital control as well. Now tell me which is most suitable cuk or conventional buck-boost. Though cuk has more comments compare to buck boost. Cuk will be costly solution compare to buck boost. What about efficiency at 700w power level.just to add one more point size is not a big constraint .now Which is best?

0 Timothy Hegarty 2 hours ago in reply to Nitesh Modi

TI__Guru 52122 points

Neither of those is suitable for 700W. Go with the 4-switch buck-boost regulator.

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LM5148-Q1: Solar - PV optimizer Design & Development -Power Topology Selection