TMS320F28069F: In-line current sensing with transducers

Jordan Zhou

Genius 10180 points

Part Number: TMS320F28069F

Hi,
In-line current transducers (from LEM) are used for 3 phase current sensing.

The SCH is as below.

What's the current feedback type, negative or positive? For this kind of current sensing, what shall we take care of?

Thanks a lot.

Br, Jordan

over 8 years ago

0 Ramesh Ramamoorthy over 8 years ago

TI__Mastermind 27240 points

It looks like the output voltage will move positive when the current is flowing out of the inverter. You need to make sure that at the sensor is appropriated rated for max possible current.

0 Jordan Zhou over 8 years ago in reply to Ramesh Ramamoorthy

TI__Genius 10180 points

Ramesh,
Thanks.
In InstaSPIN, is there any way to identify, by read current ADC values? Or, if the code uses the wrong positive/negative, what will happen in InstaSPIN?
Br, Jordan

0 Ramesh Ramamoorthy over 8 years ago in reply to Jordan Zhou

TI__Mastermind 27240 points

If you apply a positive Vd or Vq and get the feedback Id or Iq as positive, then it means that you got right sense of measurement.

0 Jordan Zhou over 8 years ago in reply to Ramesh Ramamoorthy

TI__Genius 10180 points

What about the PWM SOC generate point "PWM_SocPulseSrc_CounterEqualZero". For in-line current sensing, is this sensing point OK?
Br, Jordan

0 Ramesh Ramamoorthy over 8 years ago in reply to Jordan Zhou

TI__Mastermind 27240 points

Yes.

rgds,

ramesh

0 Jordan Zhou over 8 years ago in reply to Ramesh Ramamoorthy

TI__Genius 10180 points

Currently, customer faced one issue on lab2b, to identify motor parameters. After the first steps of RoverL and RS, during RampUp, immediately a pure hardware over current protection happened. It's open loop, what could be the issues?
Thanks a lot.
Br, Jordan

0 Yanming Luo over 8 years ago in reply to Jordan Zhou

TI__Guru** 116140 points

Use lab01b of mw18 to verify the sign and scale of sensing current. In Ramp_up state, motor run with position open loop, but with current close loop.

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TMS320F28069F: In-line current sensing with transducers