CCS/TMS320F28035: single-phase SOGI PLL

Iv Y

Part Number: TMS320F28035

Tool/software: Code Composer Studio

Hi TI experts,

I have implemented the single-phase SOGI PLL provided by TI. It works well. But I do not know which parameter should I use from the following structure in SPLL_1ph_SOGI_IQ.h, if I want to know the rms amplitude of a single-phase AC? I need this in order to detect possible grid under-voltage.

typedef struct{
int32 u[3]; // Ac Input
int32   osg_u[3];
int32   osg_qu[3];
int32   u_Q[2];
int32   u_D[2];
int32   ylf[2];
int32   fo; // output frequency of PLL
int32   fn; //nominal frequency
int32 theta[2];
int32 cos;
int32 sin;
int32   delta_T;
SPLL_1ph_SOGI_IQ_OSG_COEFF osg_coeff;
SPLL_1ph_SOGI_IQ_LPF_COEFF lpf_coeff;
}SPLL_1ph_SOGI_IQ;

Thank you in advance for your help!

over 6 years ago

0 Manish Bhardwaj over 6 years ago

TI__Mastermind 43730 points

Ivan the module does not support RMS voltage calculation.

You can do the RMS voltage calculation of the fundamental harmonic in your code by using Q and D component,

We use amplitude invariant transformation for d q axis hence what you will get in those axis is the amplitude of the vac or the peak pu value.

You can calculate RMS from that.

0 Manish Bhardwaj over 6 years ago

TI__Mastermind 43730 points

Ivan any updates?

0 Iv Y over 6 years ago in reply to Manish Bhardwaj

Intellectual 390 points

Sorry for the late reply.

Your proposed solution to use u_d works well, despite the following two minor issues.

(1) a small 50Hz or 60Hz ripple appears on top of the peak value. But it is tolerable.

(2) u_d is negative, I guess, due to the definition of dq axis. I can use abs() to get the right answer.

Again, I get what I want. Thank you so much for your help.

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CCS/TMS320F28035: single-phase SOGI PLL