spll_1ph_notch.h

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//#############################################################################
//
//  FILE      spll_1ph_notch.h
//
//  TITLE     Notch Filter based Software Phase Lock Loop (SPLL) 
//            for Single Phase Grid Module
//
//#############################################################################
 
#ifndef SPLL_1PH_NOTCH_H
#define SPLL_1PH_NOTCH_H
 
#ifdef __cplusplus
extern "C" {
#endif
 
//
// Typedefs
//
//
// Included Files
//
#include <stdint.h>
#include <math.h>
 
//#############################################################################
//
// Macro Definitions
//
//#############################################################################
#ifndef IEEE754_TYPES
#define IEEE754_TYPES
typedef float         float32_t;
typedef double        float64_t;
#endif // IEEE754_TYPES
 
 
 
typedef struct{
    float32_t b2;
    float32_t b1;
    float32_t b0;
    float32_t a2;
    float32_t a1;
} SPLL_1PH_NOTCH_COEFF;
 
typedef struct{
    float32_t b1;
    float32_t b0;
    float32_t a1;
} SPLL_1PH_NOTCH_LPF_COEFF;
 
typedef struct{
    float32_t   upd[3];       
    float32_t   y_notch1[3];  
    float32_t   y_notch2[3];  
    float32_t   ylf[2];       
    float32_t   fo;           
    float32_t   fn;           
    float32_t   theta;        
    float32_t   cosine;       
    float32_t   sine;         
    float32_t   delta_t;      
    SPLL_1PH_NOTCH_COEFF notch_coeff; 
    SPLL_1PH_NOTCH_LPF_COEFF lpf_coeff;     
} SPLL_1PH_NOTCH;
 
static inline void SPLL_1PH_NOTCH_reset(SPLL_1PH_NOTCH *spll_obj)
{
    spll_obj->upd[0]=(float32_t)(0.0);
    spll_obj->upd[1]=(float32_t)(0.0);
    
    spll_obj->y_notch1[0]=(float32_t)(0.0);
    spll_obj->y_notch1[1]=(float32_t)(0.0);
    spll_obj->y_notch1[2]=(float32_t)(0.0);
    
    spll_obj->y_notch2[0]=(float32_t)(0.0);
    spll_obj->y_notch2[1]=(float32_t)(0.0);
    spll_obj->y_notch2[2]=(float32_t)(0.0);
    
    spll_obj->ylf[0]=(float32_t)(0.0);
    spll_obj->ylf[1]=(float32_t)(0.0);
    
    spll_obj->fo=(float32_t)(0.0);
    
    spll_obj->theta=(float32_t)(0.0);
 
    spll_obj->sine=(float32_t)(0.0);
    spll_obj->cosine=(float32_t)(0.0);
}
 
static inline void SPLL_1PH_NOTCH_coeff_calc(SPLL_1PH_NOTCH *spll_obj,
                                             float32_t c1, float32_t c2)
{
    float32_t notch_freq;
    float32_t temp1,temp2;
    float32_t wn2;
    float32_t Ts, Fs;
 
    notch_freq=2*3.14159265f*spll_obj->fn;
    Ts = spll_obj->delta_t;
    Fs=1/Ts;
 
    //
    // pre warp the notch frequency
    //
    wn2=2*Fs*tanf(notch_freq* ((float32_t)3.141592653589)*Ts);
 
    temp1= 4*Fs*Fs + 4* wn2 * c2 * Fs + wn2*wn2;
    temp2= 1/ ( 4*Fs*Fs + 4* wn2 * c1 * Fs + wn2*wn2);
 
    spll_obj->notch_coeff.b0 = temp1* temp2;
    spll_obj->notch_coeff.b1 = (-8*Fs*Fs + 2* wn2* wn2)* temp2;
    spll_obj->notch_coeff.b2 = (4*Fs*Fs-4*wn2*c2*Fs+wn2*wn2)*temp2;
    spll_obj->notch_coeff.a1 = (-8*Fs*Fs + 2* wn2* wn2)*temp2;
    spll_obj->notch_coeff.a2 = (4*Fs*Fs-4*wn2*c1*Fs+wn2*wn2)*temp2;
}
 
 
static inline void SPLL_1PH_NOTCH_config(SPLL_1PH_NOTCH *spll_obj,
                         float32_t acFreq,
                         float32_t isrFrequency,
                         float32_t lpf_b0,
                         float32_t lpf_b1,
                         float32_t c1,
                         float32_t c2
                         )
{
    spll_obj->fn=acFreq;
    spll_obj->delta_t=((1.0f)/isrFrequency);
 
    SPLL_1PH_NOTCH_coeff_calc( spll_obj,
                                   c1,
                                   c2);
 
    spll_obj->lpf_coeff.b0=lpf_b0;
    spll_obj->lpf_coeff.b1=lpf_b1;
}
 
static inline void SPLL_1PH_NOTCH_run(SPLL_1PH_NOTCH *spll_obj,
                                      float32_t acValue)
{
    //
    // Phase detect
    //
    spll_obj->upd[0] = acValue*spll_obj->cosine;
    
    //
    // Notch Filter
    //
    spll_obj->y_notch1[0] = - spll_obj->y_notch1[1]*spll_obj->notch_coeff.a1
                            - spll_obj->y_notch1[2]*spll_obj->notch_coeff.a2
                            + spll_obj->upd[0]*spll_obj->notch_coeff.b0
                            + spll_obj->upd[1]*spll_obj->notch_coeff.b1
                            + spll_obj->upd[2]*spll_obj->notch_coeff.b2;
 
    spll_obj->y_notch2[0] = - spll_obj->y_notch2[1]*spll_obj->notch_coeff.a1
                            - spll_obj->y_notch2[2]*spll_obj->notch_coeff.a2
                            + spll_obj->y_notch1[0]*spll_obj->notch_coeff.b0
                            + spll_obj->y_notch1[1]*spll_obj->notch_coeff.b1
                            + spll_obj->y_notch1[2]*spll_obj->notch_coeff.b2;
 
    //
    // Loop Filter
    //
    spll_obj->ylf[0] = spll_obj->ylf[1]
                    + (spll_obj->lpf_coeff.b0*spll_obj->y_notch2[0])
                    + (spll_obj->lpf_coeff.b1*spll_obj->y_notch2[1]);
 
    //spll_obj->ylf[0] = (spll_obj->ylf[0]>100)?100:spll_obj->ylf[0];
    //spll_obj->ylf[0] = (spll_obj->ylf[0]<-100)?-100:spll_obj->ylf[0];
 
    //
    // update the Upd array for future sample
    //
    spll_obj->upd[2] = spll_obj->upd[1];
    spll_obj->upd[1] = spll_obj->upd[0];
 
    spll_obj->y_notch1[2] = spll_obj->y_notch1[1];
    spll_obj->y_notch1[1] = spll_obj->y_notch1[0];
 
    spll_obj->y_notch2[2] = spll_obj->y_notch2[1];
    spll_obj->y_notch2[1] = spll_obj->y_notch2[0];
 
    spll_obj->ylf[1] = spll_obj->ylf[0];
 
    //
    // VCO
    //
    spll_obj->fo = spll_obj->fn+spll_obj->ylf[0];
 
    spll_obj->theta= spll_obj->theta
          + (spll_obj->fo*spll_obj->delta_t)*(float32_t)(2.0*3.1415926);
 
    if(spll_obj->theta>(float32_t)(2.0*3.1415926))
    {
        spll_obj->theta =spll_obj->theta-(float32_t)(2.0*3.1415926);
    }
 
    spll_obj->sine = (float32_t)sinf(spll_obj->theta);
    spll_obj->cosine = (float32_t)cosf(spll_obj->theta);
}
 
// Close the Doxygen group.
#ifdef __cplusplus
}
#endif // extern "C"
 
#endif  // end of  _SPLL_1PH_NOTCH_H_ definition
 
 
//
// End of File
//