TIDM-02008: Notch filter configuration in TIDM-02008

Minghan Dong

Prodigy 40 points

Part Number: TIDM-02008

Hi expert,

I met a question when I develop solar inverter/PFC based on C2000/TIDM-02008.

The global variable initialization functions use 120Hz/100Hz to configure the notch filters for voltage loop.

Why use wn2 = 2 * Fs * tanf(120Hz/100Hz * pi * Ts) as notch frequency in the function?

What's the meaning of 2* tanf(120Hz/100Hz * pi * Ts) / (1/Ts)? Although its equal to 120Hz/100Hz * 2pi when Ts is very small.

over 1 year ago

0 Minghan Dong over 1 year ago

Prodigy 40 points

Hi Expert,

Awaiting for your kindly reply.

Another detail need to check:

Should temp1 use "double(float64_t)" rather than float32_t?

Because the temp1 is really small about 2.498e-9 with c1=0.25 c2=0.00001. If use float, the precision(float32 1e-7) will be not suitable?

0 Amir Hussain over 1 year ago in reply to Minghan Dong

TI__Expert 3615 points

Hello Minghan

Please spare me some time. I will discuss this with the internal team and get back to you.

Thank you

Amir Hussain

0 Minghan Dong over 1 year ago in reply to Amir Hussain

Prodigy 40 points

Hi Amir,

Could you share any progress?

Thanks

0 Minghan Dong over 1 year ago in reply to Amir Hussain

Prodigy 40 points

Do you have any feedback?

0 Amir Hussain over 1 year ago in reply to Minghan Dong

TI__Expert 3615 points

Hello Minghan

Currently I am occupied with other high priority work. Please spare me more time.

Thank you

Amir Hussain

0 Amir Hussain over 1 year ago in reply to Minghan Dong

TI__Expert 3615 points

Hello Minghan

We do not have appnote to explain the design of the notch filter and your specific question. However, I am sharing the below link which seems useful to give some insights on how notch filter is implemented.

https://arachnoid.com/BiQuadDesigner/index.html

Thanks

Amir

C2000™︎ microcontrollers

C2000 microcontrollers forum

TIDM-02008: Notch filter configuration in TIDM-02008