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CCS/C2000-DIGITAL-CONTROL-LIBRARY: Field Oriented Control of IPM Motor (d-axis phase delay problem)

Furkan Aydogan1
Intellectual 450 points

Part Number: C2000-DIGITAL-CONTROL-LIBRARY

Tool/software: Code Composer Studio

Edit: Problem resolved. It was just a sensor setup error and does not related abut the control software.

Hi,

We are designing an IPM motor controller and have a problem. I would like to get your suggestions about it. In abstract, when driving IPM with zero d-axis current (id=0), there is a phase delay between rotor d-axis and phase current (Ia). However, i expect d-axis of rotor should be synchronized with zero crossing of phase A current. Wepply q-axis current from inverter (keeping d-axis current at zero, id=0) and observe Z-pulse and phase current:

CH3 : Ia (phase A current) CH4: Encoder zero pulse (Z pulse)

 

Here is the problem. There is a phase delay (approximately 45 electrical degrees) between phase A current and rotor zero position. I expect zero crossing of phase A current and zero position of rotor should coincides (zero phase delay). I repeated the process for differenct speed and load conditions and phase delay is always near 45 degrees.

I would appreciate it if you have an opinion and forward your suggestions about the problem.

  • 0
    TI__Guru** 117210 points

    The reference assumes the PM motor is an SPM motor and sets the reference Id to zero always. Just for your reference, you may have to set a non-zero value to the reference Id if you are using an IPM motor.

  • 0 in reply to Yanming Luo
    Intellectual 450 points

    That is true IPM motor should have some negative d-axis current to obtain maximum torque but this is not a mandatory. You can still keep d-axis current to zero (as already seen by simulation results). So i think problem is not the motor type.

  • 0 in reply to Furkan Aydogan1
    TI__Guru** 117210 points

    Right, but you should get the correct rotor position based on the motor model, if not, the phase delay will be generated.

    Btw, on this forum we are able to support specific device and reference code related questions. I feel your question requires extensive research and knowledge of simulation. You may post this question to some engineering forums or MathWorks forum.