CCS/TMS320F28054F: Lab21, the equation of excitation frequency

Arrow Wu

Intellectual 530 points

Part Number: TMS320F28054F

Tool/software: Code Composer Studio

Hi,

I'm readiing user guide of lab 21, for IPD and HFI.

The equation of excitation frequency seems somewhere wrong.

What shows on page 340 of 'InstaSPIN Projects and Labs User’s Guide' (version 1.0.16) is as below.

However, the result 830Hz is not the calculated answer.

Is there something wrong?

best regards

Arrow

over 6 years ago

0 Yanming Luo over 6 years ago

TI__Guru** 110580 points

The actual excitation frequency depends PWM frequency also, which near the calculation frequency, had a description in guide.

0 Arrow Wu over 6 years ago in reply to Yanming Luo

Intellectual 530 points

Hi, I'm afraid you didn't catch what I mentioned about.

I am just asking this simple equation.

0.12/230u * 10 = 5217Hz , not 830Hz.

And I just found the reason.

the right equation should be 0.12/230u *10 /(2*pi) = 830Hz .

Am I right?

If so , maybe it needs to be revised.

0 Yanming Luo over 6 years ago in reply to Arrow Wu

TI__Guru** 110580 points

Right. The calculation equation is fc=R/(2*PI*L), and use the 10 times of fc for HFI frequency, so the calculated value is 830Hz. We will correct this. Thanks.

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CCS/TMS320F28054F: Lab21, the equation of excitation frequency