• This embedded C-library provides the various types of Induction Motor estimators to implementation the FOC control systems:

  • Sensored rotor flux (angle, magnitude) and back-EMF observer
  • Sensorless stator back-EMF observer
  • Sensorless rotor speed and flux (angle, magnitude) observer

• Project structure

  • README.md - current file
  • LICENSE - file with license description
  • fp_pid.h - C-header file with user data types and function prototypes (P/I/D library)
  • fp_pid.c - C-source file with firmware functions (P/I/D library)
  • im_estimators.h - C-header file with user data types and function prototypes (Induction Motor estimators library)
  • im_estimators.c - C-source file with firmware functions (Induction Motor estimators library)

• Example 1 - Stator back-EMF observer

    #include "im_estimators.h"
    
    // Measurable values of stator voltages and currents:
    float IsAl, IsBe, UsAl, UsBe;
    
    // Observable value of stator back-EMF:
    float EsAl, EsBe;
    
    // 1st step: create and initialize the global variables of user data structures
    tIMparams IMparams = IM_PARAMS_DEFAULTS;
    tIMstatObs sIMstatObs = IM_STAT_OBS_DEFAULTS;
    
    // 2nd step: do some settings
    IMparams.fDt = 0.0001f;         // set the discretization (sample) time
    IMparams.fNpP = 2.0f;           // set the count of stator pole pairs
    IMparams.fRr = 4.516f;          // set the rotor resistance constant
    IMparams.fRs = 50.0f;           // set the stator resistance constant
    IMparams.fLr = 0.143f;          // set the rotor inductance constant
    IMparams.fLs = 0.143f;          // set the stator inductance constant
    IMparams.fLm = 0.14f;           // set the magnetizing inductance constant
    IMparams.m_init(&IMparams);     // call the initialization function of induction motor parameters
    
    // 3rd step: Next code must be executed every time with IMparams.fDt period when 
    // new calculation of Stator back-EMF values is needed
    sIMstatObs.fIsAl = IsAl;        // update the stator current Alpha
    sIMstatObs.fIsBe = IsBe;        // update the stator current Beta
    sIMstatObs.fUsAl = UsAl;        // update the stator voltage Alpha
    sIMstatObs.fUsBe = UsBe;        // update the stator voltage Beta
    sIMstatObs.m_calc(&sIMstatObs, &IMparams); // call the Stator back-EMF observer function
    EsAl = sIMstatObs.fEsAl;        // observed stator back-EMF voltage Alpha
    EsBe = sIMstatObs.fEsBe;        // observed stator back-EMF voltage Beta
  

• Example 2 - Rotor flux and back-EMF observer

    #include "im_estimators.h"
    
    // Measurable values of stator currents:
    float IsAl, IsBe;
    
    // Measurable value of rotor mechanical speed (Rad/Sec):
    float Wr;
    
    // Observable values of rotor back-EMF and flux:
    float ErAl, ErBe, Fang, Fmag;
    
    // 1st step: create and initialize the global variables of user data structures
    tIMparams IMparams = IM_PARAMS_DEFAULTS;
    tIMrotObs IMrotObs = IM_ROT_OBS_DEFAULTS;
    
    // 2nd step: do some settings
    IMparams.fDt = 0.0001f;         // set the discretization (sample) time
    IMparams.fNpP = 2.0f;           // set the count of stator pole pairs
    IMparams.fRr = 4.516f;          // set the rotor resistance constant
    IMparams.fRs = 50.0f;           // set the stator resistance constant
    IMparams.fLr = 0.143f;          // set the rotor inductance constant
    IMparams.fLs = 0.143f;          // set the stator inductance constant
    IMparams.fLm = 0.14f;           // set the magnetizing inductance constant
    IMparams.m_init(&IMparams);     // call the initialization function of induction motor parameters
    
    // 3rd step: Next code must be executed every time with IMparams.fDt period when 
    // new calculation of rotor back-EMF and flux values is needed
    IMrotObs.fIsAl = IsAl;          // update the stator current Alpha
    IMrotObs.fIsBe = IsBe;          // update the stator current Beta
    IMrotObs.fWrE = Wr*IMparams.fNpP; // update the rotor electrical speed value
    IMrotObs.m_calc(&IMrotObs, &IMparams); // call the rotor back-EMF and flux observer function
    ErAl = IMrotObs.fErAl;          // observed rotor back-EMF voltage Alpha
    ErBe = IMrotObs.fErBe;          // observed rotor back-EMF voltage Beta
    Fang = atan2f(IMrotObs.fFrAl, IMrotObs.fFrBe); // observed rotor flux angle
    Fmag = hypotf(IMrotObs.fFrAl, IMrotObs.fFrBe); // observed rotor flux magnitude
  

• Example 3 - Rotor speed and flux observer

    // Measurable values of stator voltages and currents:
    float IsAl, IsBe, UsAl, UsBe;
    
    // Observable value of rotot mechanical speed (Rad/Sec):
    float Wr;
    
    // Observable values of rotor flux:
    float Fang, Fmag;
    
    // 1st step: create and initialize the global variables of user data structures
    tIMparams IMparams = IM_PARAMS_DEFAULTS;
    tIMspeedObs sIMspeedObs = IM_SPEED_OBS_DEFAULTS;
    
    // 2nd step: do some settings
    IMparams.fDt = 0.0001f;         // set the discretization (sample) time
    IMparams.fNpP = 2.0f;           // set the count of stator pole pairs
    IMparams.fRr = 4.516f;          // set the rotor resistance constant
    IMparams.fRs = 50.0f;           // set the stator resistance constant
    IMparams.fLr = 0.143f;          // set the rotor inductance constant
    IMparams.fLs = 0.143f;          // set the stator inductance constant
    IMparams.fLm = 0.14f;           // set the magnetizing inductance constant
    IMparams.m_init(&IMparams);     // call the initialization function of induction motor parameters
    // configure the speed observer adapter based on PI-controller:
    sIMspeedObs.sPI.fDtSec = IMparams.fDt; // set the discretization (sample) time for PI-controller
    sIMspeedObs.sPI.fKp = 0.1f;     // set the proportional coefficient of PI-controller
    sIMspeedObs.sPI.fKp = 0.01f;    // set the integral coefficient of PI-controller
    sIMspeedObs.sPI.fUpOutLim = 300.0f; // set the PI-controller's output upper limit (Max rotor electrical speed value)
    sIMspeedObs.sPI.fUpOutLim = -300.0f;// set the PI-controller's output lower limit (Min rotor electrical speed value)
    
    // 3rd step: Next code must be executed every time with IMparams.fDt period when 
    // new calculation of rotor speed and flux values is needed
    sIMspeedObs.fIsAl = IsAl;       // update the stator current Alpha
    sIMspeedObs.fIsBe = IsBe;       // update the stator current Beta
    sIMspeedObs.fUsAl = UsAl;       // update the stator voltage Alpha
    sIMspeedObs.fUsBe = UsBe;       // update the stator voltage Beta
    sIMspeedObs.m_calc(&sIMspeedObs, &IMparams); // call the rotor speed and flux observer function
    Wr = sIMspeedObs.fWrE/IMparams.fNpP; // observed rotor mechanical speed
    Fang = sIMspeedObs.fFrAng;      // observed rotor flux angle
    Fmag = sIMspeedObs.fFrMagn;     // observed rotor flux magnitude
  

MIT