CCS/TMS320F28035-EP: PMSM sesorless control---ESMO's Gsmopos Para. and PHASEVOLT_MACRO question

Arrow Wu

Intellectual 530 points

Part Number: TMS320F28035-EP

Tool/software: Code Composer Studio

I have two questions about the HVPM_Sensorless control project.

1. in SMOPOS_CONST.C file，

v.Gsmopos = (v.Vb/v.Ib)*(1/v.Rs)*(1-v.Fsmopos);

why there is v.Vb/v.Ib in the Gsmopos Para. ? Is it necessary in the SMO observer?

in DMC MATH_V13.1 .pdf file, Page 123, Gs = (1/R) *(1- exp(-R*Ts/L)).

and Vb means the full scale ADC bus voltage?

2. in PHASEVOLT_MACRO,

volt1.MfuncV1 = svgen1.Ta;
volt1.MfuncV2 = svgen1.Tb;
volt1.MfuncV3 = svgen1.Tc;

however ,svgen1.Tx's range is from (-1,1). It seems that the volt1.MfuncV1 should come from the real duty rate (0,1)

like -0.5 * svgen1.Ta + 0.5.

from PHASEVOLT_MACRO, the valpha and vbeta's value is about twice than the normal duty rate.

thanks.

best regards

Arrow

over 4 years ago

0 Ramesh Ramamoorthy over 4 years ago

TI__Mastermind 27240 points

1. Because the adc read is done in per unit, it becomes necessary. Vb is the full scale dc bus voltage as sensed by the ADC.

2. True, the intent is to fit the sine values within the COMP range used in the EPWM peripheral. This effectively adds a 50% dutycycle as common mode voltage for all three phases, but they cancel out in line and do not produce any currents through the motor.

0 Arrow Wu over 4 years ago in reply to Ramesh Ramamoorthy

Intellectual 530 points

Thanks.

1. I got it.

2. What I'm confused with is that the output of PHASEVOLT_MACRO is the input of ESMO module, and the valpha and vbeta uses twice the real value.

If the valpha and vbeta is doube, does it affect the Sliding Mode Current Observer ?

As far as I'm concerned, to the formula below

v->EstIalpha = _IQmpy(v->Fsmopos,v->EstIalpha) + _IQmpy(v->Gsmopos,(v->Valpha-v->Ealpha-v->Zalpha));

Ealpha is almost equal to Zalpha, that is (Ealpha+Zalpha) is almost double the real back EMF, so the Valpha should be twice the real value.

Am I right?

Regards

Arrow

0 Ramesh Ramamoorthy over 4 years ago in reply to Arrow Wu

TI__Mastermind 27240 points

Ealpha and Zalpha will differ in time because of the filtering effect.

0 Arrow Wu over 4 years ago in reply to Ramesh Ramamoorthy

Intellectual 530 points

Sorry, then I don't understand why uses the doube value of the real valpha/vbeta for the ESMO module?

CAN I use the real duty rate (0~1)for the PHASEVOLT_MACRO, rather than (-1,1)?

Arrow

0 Ramesh Ramamoorthy over 4 years ago in reply to Arrow Wu

TI__Mastermind 27240 points

No, you should use Valpha and Vbeta only. The duty cycle is modulated based on this.

0 Arrow Wu over 4 years ago in reply to Ramesh Ramamoorthy

Intellectual 530 points

Duty cycle is based on PWM_MACRO(1,2,3,pwm1) function.

like (*ePWM[ch1]).CMPA.half.CMPA = _IQmpy(m.HalfPerMax,-m.MfuncC1)+ m.HalfPerMax;

PHASEVOLT_MACRO is just for ESMO' valpha and vbeta input.

The simulation of this macro using SVGEN1.Tx or Dx(x = A,B,C) is in the attached file.(Dx = -0.5 *Tx + 0.5)

I just found the SVGEN1.Tx is not the real phase voltage,and can't understand the following explanation.

0 Arrow Wu over 4 years ago in reply to Arrow Wu

Intellectual 530 points

And the ESMO module doesn't use the real phase voltage for position estimation.

It use the red line for phase voltage calculation.

Am I right ?

0 Ramesh Ramamoorthy over 4 years ago in reply to Arrow Wu

TI__Mastermind 27240 points

Keep in mind that the dutycycle loaded into comp is in pu.That is the missing link between the implementation and your understanding if I am correct...

0 Arrow Wu over 4 years ago in reply to Ramesh Ramamoorthy

Intellectual 530 points

I got it ,thanks.

regards

Arrow

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CCS/TMS320F28035-EP: PMSM sesorless control---ESMO's Gsmopos Para. and PHASEVOLT_MACRO question