foc.cpp

00001 
00002 #include "foc.h"
00003 using namespace FastMath;
00004 
00005 
00006 void abc( float theta, float d, float q, float *a, float *b, float *c){
00007     /// Inverse DQ0 Transform ///
00008     ///Phase current amplitude = lengh of dq vector///
00009     ///i.e. iq = 1, id = 0, peak phase current of 1///
00010     float cf = FastCos(theta);
00011     float sf = FastSin(theta);
00012     
00013     *a = cf*d - sf*q;                // Faster Inverse DQ0 transform
00014     *b = (0.86602540378f*sf-.5f*cf)*d - (-0.86602540378f*cf-.5f*sf)*q;
00015     *c = (-0.86602540378f*sf-.5f*cf)*d - (0.86602540378f*cf-.5f*sf)*q;
00016     }
00017     
00018     
00019 void dq0(float theta, float a, float b, float c, float *d, float *q){
00020     /// DQ0 Transform ///
00021     ///Phase current amplitude = lengh of dq vector///
00022     ///i.e. iq = 1, id = 0, peak phase current of 1///
00023     
00024     float cf = FastCos(theta);
00025     float sf = FastSin(theta);
00026     
00027     *d = 0.6666667f*(cf*a + (0.86602540378f*sf-.5f*cf)*b + (-0.86602540378f*sf-.5f*cf)*c);   ///Faster DQ0 Transform
00028     *q = 0.6666667f*(-sf*a - (-0.86602540378f*cf-.5f*sf)*b - (0.86602540378f*cf-.5f*sf)*c);
00029        
00030     }
00031     
00032 void svm(float v_bus, float u, float v, float w, int i_sector, float *dtc_u, float *dtc_v, float *dtc_w){
00033     /// Space Vector Modulation ///
00034     /// u,v,w amplitude = v_bus for full modulation depth ///
00035     
00036     float v_offset = (fminf3(u, v, w) + fmaxf3(u, v, w))*0.5f;
00037     
00038     // Dead-time compensation
00039     float u_comp = DTC_COMP*(-(i_sector==4) + (i_sector==3));
00040     float v_comp = DTC_COMP*(-(i_sector==2) + (i_sector==5));
00041     float w_comp = DTC_COMP*((i_sector==6) - (i_sector==1));
00042     
00043     
00044     *dtc_u = fminf(fmaxf((.5f*(u -v_offset)/(v_bus*(DTC_MAX-DTC_MIN)) + (DTC_MAX+DTC_MIN)*.5f + u_comp), DTC_MIN), DTC_MAX);
00045     *dtc_v = fminf(fmaxf((.5f*(v -v_offset)/(v_bus*(DTC_MAX-DTC_MIN)) + (DTC_MAX+DTC_MIN)*.5f + v_comp), DTC_MIN), DTC_MAX);
00046     *dtc_w = fminf(fmaxf((.5f*(w -v_offset)/(v_bus*(DTC_MAX-DTC_MIN)) + (DTC_MAX+DTC_MIN)*.5f + w_comp), DTC_MIN), DTC_MAX); 
00047     
00048     /*
00049     sinusoidal pwm
00050     *dtc_u = fminf(fmaxf((u/v_bus + .5f), DTC_MIN), DTC_MAX);
00051     *dtc_v = fminf(fmaxf((v/v_bus + .5f), DTC_MIN), DTC_MAX);
00052     *dtc_w = fminf(fmaxf((w/v_bus + .5f), DTC_MIN), DTC_MAX);
00053     */
00054      
00055     
00056     }
00057 
00058 void zero_current(int *offset_1, int *offset_2){                                // Measure zero-offset of the current sensors
00059     int adc1_offset = 0;
00060     int adc2_offset = 0;
00061     int n = 1024;
00062     for (int i = 0; i<n; i++){                                                  // Average n samples of the ADC
00063         TIM1->CCR3 = (PWM_ARR>>1)*(1.0f);                                               // Write duty cycles
00064         TIM1->CCR2 = (PWM_ARR>>1)*(1.0f);
00065         TIM1->CCR1 = (PWM_ARR>>1)*(1.0f);
00066         ADC1->CR2  |= 0x40000000;                                               // Begin sample and conversion
00067         wait(.001);
00068         adc2_offset += ADC2->DR;
00069         adc1_offset += ADC1->DR;
00070         }
00071     *offset_1 = adc1_offset/n;
00072     *offset_2 = adc2_offset/n;
00073     }
00074     
00075 void init_controller_params(ControllerStruct *controller){
00076     controller->ki_d = KI_D;
00077     controller->ki_q = KI_Q;
00078     controller->k_d = K_SCALE*I_BW;
00079     controller->k_q = K_SCALE*I_BW;
00080     controller->alpha = 1.0f - 1.0f/(1.0f - DT*I_BW*2.0f*PI);
00081     for(int i = 0; i<128; i++)
00082     {
00083         controller->inverter_tab[i] = 1.0f + 1.2f*exp(-0.0078125f*i/.032f);
00084     }
00085     }
00086 
00087 void reset_foc(ControllerStruct *controller){
00088     TIM1->CCR3 = (PWM_ARR>>1)*(0.5f);
00089     TIM1->CCR1 = (PWM_ARR>>1)*(0.5f);
00090     TIM1->CCR2 = (PWM_ARR>>1)*(0.5f);
00091     controller->i_d_ref = 0;
00092     controller->i_q_ref = 0;
00093     controller->i_d = 0;
00094     controller->i_q = 0;
00095     controller->i_q_filt = 0;
00096     controller->q_int = 0;
00097     controller->d_int = 0;
00098     controller->v_q = 0;
00099     controller->v_d = 0;
00100     controller->otw_flag = 0;
00101 
00102     }
00103     
00104 void reset_observer(ObserverStruct *observer){
00105     
00106     observer->temperature = 25.0f;
00107     observer->temp_measured = 25.0f;
00108     //observer->resistance = .1f;
00109     }
00110     
00111 void limit_current_ref (ControllerStruct *controller){
00112     float i_q_max_limit = (0.5774f*controller->v_bus - controller->dtheta_elec*WB)/R_PHASE;
00113     float i_q_min_limit = (-0.5774f*controller->v_bus - controller->dtheta_elec*WB)/R_PHASE;
00114     controller->i_q_ref = fmaxf(fminf(i_q_max_limit, controller->i_q_ref), i_q_min_limit);
00115     }
00116 
00117 void update_observer(ControllerStruct *controller, ObserverStruct *observer)
00118 {
00119     /// Update observer estimates ///
00120     // Resistance observer //
00121     // Temperature Observer //
00122     observer->delta_t = (float)observer->temperature - T_AMBIENT;
00123     float i_sq = controller->i_d*controller->i_d + controller->i_q*controller->i_q;
00124     observer->q_in = (R_NOMINAL*1.5f)*(1.0f + .00393f*observer->delta_t)*i_sq;
00125     observer->q_out = observer->delta_t*R_TH;
00126     observer->temperature += (INV_M_TH*DT)*(observer->q_in-observer->q_out);
00127     
00128     //float r_d = (controller->v_d*(DTC_MAX-DTC_MIN) + SQRT3*controller->dtheta_elec*(L_Q*controller->i_q))/(controller->i_d*SQRT3);
00129     float r_q = (controller->v_q*(DTC_MAX-DTC_MIN) - SQRT3*controller->dtheta_elec*(L_D*controller->i_d + WB))/(controller->i_q*SQRT3);
00130     observer->resistance = r_q;//(r_d*controller->i_d + r_q*controller->i_q)/(controller->i_d + controller->i_q); // voltages more accurate at higher duty cycles
00131     
00132     //observer->resistance = controller->v_q/controller->i_q;
00133     if(isnan(observer->resistance) || isinf(observer->resistance)){observer->resistance = R_NOMINAL;}
00134     float t_raw = ((T_AMBIENT + ((observer->resistance/R_NOMINAL) - 1.0f)*254.5f));
00135     if(t_raw > 200.0f){t_raw = 200.0f;}
00136     else if(t_raw < 0.0f){t_raw = 0.0f;}
00137     observer->temp_measured = .999f*observer->temp_measured + .001f*t_raw;
00138     float e = (float)observer->temperature - observer->temp_measured;
00139     observer->trust = (1.0f - .004f*fminf(abs(controller->dtheta_elec), 250.0f)) * (.01f*(fminf(i_sq, 100.0f)));
00140     observer->temperature -= observer->trust*.0001f*e;
00141     //printf("%.3f\n\r", e);
00142     
00143     if(observer->temperature > TEMP_MAX){controller->otw_flag = 1;}
00144     else{controller->otw_flag = 0;}
00145 }
00146 
00147 float linearize_dtc(ControllerStruct *controller, float dtc)
00148 {
00149     float duty = fmaxf(fminf(abs(dtc), .999f), 0.0f);;
00150     int index = (int) (duty*127.0f);
00151     float val1 = controller->inverter_tab[index];
00152     float val2 = controller->inverter_tab[index+1];
00153     return val1 + (val2 - val1)*(duty*128.0f - (float)index);
00154 }
00155 
00156 void field_weaken(ControllerStruct *controller)
00157 {
00158        /// Field Weakening ///
00159        
00160        controller->fw_int += .001f*(0.5f*OVERMODULATION*controller->v_bus - controller->v_ref);
00161        controller->fw_int = fmaxf(fminf(controller->fw_int, 0.0f), -I_FW_MAX);
00162        controller->i_d_ref = controller->fw_int;
00163        float q_max = sqrt(controller->i_max*controller->i_max - controller->i_d_ref*controller->i_d_ref);
00164        controller->i_q_ref = fmaxf(fminf(controller->i_q_ref, q_max), -q_max);
00165        //float i_cmd_mag_sq = controller->i_d_ref*controller->i_d_ref + controller->i_q_ref*controller->i_q_ref;
00166        
00167 }
00168 void commutate(ControllerStruct *controller, ObserverStruct *observer, GPIOStruct *gpio, float theta)
00169 {
00170        /// Commutation Loop ///
00171        controller->loop_count ++;   
00172        if(PHASE_ORDER){                                                                          // Check current sensor ordering
00173            controller->i_b = I_SCALE*(float)(controller->adc2_raw - controller->adc2_offset);    // Calculate phase currents from ADC readings
00174            controller->i_c = I_SCALE*(float)(controller->adc1_raw - controller->adc1_offset);
00175            }
00176         else{
00177             controller->i_b = I_SCALE*(float)(controller->adc1_raw - controller->adc1_offset);    
00178            controller->i_c = I_SCALE*(float)(controller->adc2_raw - controller->adc2_offset);
00179            }
00180        controller->i_a = -controller->i_b - controller->i_c;       
00181        if((abs(controller->i_b) > 41.0f)|(abs(controller->i_c) > 41.0f)|(abs(controller->i_a) > 41.0f)){controller->oc_flag = 1;}
00182        
00183        float s = FastSin(theta); 
00184        float c = FastCos(theta);                            
00185        dq0(controller->theta_elec, controller->i_a, controller->i_b, controller->i_c, &controller->i_d, &controller->i_q);    //dq0 transform on currents
00186        //controller->i_d = 0.6666667f*(c*controller->i_a + (0.86602540378f*s-.5f*c)*controller->i_b + (-0.86602540378f*s-.5f*c)*controller->i_c);   ///Faster DQ0 Transform
00187        //controller->i_q = 0.6666667f*(-s*controller->i_a - (-0.86602540378f*c-.5f*s)*controller->i_b - (0.86602540378f*c-.5f*s)*controller->i_c);
00188         
00189         controller->i_q_filt = 0.95f*controller->i_q_filt + 0.05f*controller->i_q;
00190         controller->i_d_filt = 0.95f*controller->i_d_filt + 0.05f*controller->i_d;
00191         
00192         
00193         // Filter the current references to the desired closed-loop bandwidth
00194         //controller->i_d_ref_filt = (1.0f-controller->alpha)*controller->i_d_ref_filt + controller->alpha*controller->i_d_ref;
00195         //controller->i_q_ref_filt = (1.0f-controller->alpha)*controller->i_q_ref_filt + controller->alpha*controller->i_q_ref;
00196         
00197         controller->i_max = I_MAX*(!controller->otw_flag) + I_MAX_CONT*controller->otw_flag;
00198         
00199         // Temperature Controller //
00200         /*
00201         if(observer->temperature > TEMP_MAX)
00202         {
00203             float qdot_des = 1.0f*(TEMP_MAX - observer->temperature);
00204             float i_limit = sqrt((qdot_des + observer->q_out)/(R_NOMINAL*1.5f));
00205             controller->i_max = fmaxf(fminf(i_limit, I_MAX), I_MAX_CONT);
00206         }
00207         else{controller->i_max = I_MAX;}
00208         */
00209         
00210         limit_norm(&controller->i_d_ref, &controller->i_q_ref, controller->i_max);
00211 
00212        /// PI Controller ///
00213        float i_d_error = controller->i_d_ref - controller->i_d;
00214        float i_q_error = controller->i_q_ref - controller->i_q;//  + cogging_current;
00215        
00216        // Calculate feed-forward voltages //
00217        float v_d_ff = SQRT3*(0.0f*controller->i_d_ref*R_PHASE  - controller->dtheta_elec*L_Q*controller->i_q);   //feed-forward voltages
00218        float v_q_ff =  SQRT3*(0.0f*controller->i_q_ref*R_PHASE +  controller->dtheta_elec*(L_D*controller->i_d + 0.0f*WB));
00219        
00220        // Integrate Error //
00221        controller->d_int += controller->k_d*controller->ki_d*i_d_error;   
00222        controller->q_int += controller->k_q*controller->ki_q*i_q_error;
00223        
00224        controller->d_int = fmaxf(fminf(controller->d_int, OVERMODULATION*controller->v_bus), - OVERMODULATION*controller->v_bus);
00225        controller->q_int = fmaxf(fminf(controller->q_int, OVERMODULATION*controller->v_bus), - OVERMODULATION*controller->v_bus); 
00226        
00227        //limit_norm(&controller->d_int, &controller->q_int, OVERMODULATION*controller->v_bus);     
00228        controller->v_d = controller->k_d*i_d_error + controller->d_int;// + v_d_ff;  
00229        controller->v_q = controller->k_q*i_q_error + controller->q_int;// + v_q_ff; 
00230        //controller->v_q = 0.0f;
00231        //controller->v_d = 1.0f*controller->v_bus;
00232        controller->v_ref = sqrt(controller->v_d*controller->v_d + controller->v_q*controller->v_q);
00233        
00234        limit_norm(&controller->v_d, &controller->v_q, OVERMODULATION*controller->v_bus);       // Normalize voltage vector to lie within curcle of radius v_bus
00235        float dtc = controller->v_ref/controller->v_bus;
00236        float scale = linearize_dtc(controller, dtc);
00237        //controller->v_d = scale*controller->v_d;
00238        //controller->v_q = scale*controller->v_q;
00239        //float dtc_q = controller->v_q/controller->v_bus;
00240        
00241        //linearize_dtc(&dtc_q);
00242        //controller->v_d = dtc_d*controller->v_bus;
00243        //controller->v_q = dtc_q*controller->v_bus;
00244        abc(controller->theta_elec + 0.0f*DT*controller->dtheta_elec, scale*controller->v_d, scale*controller->v_q, &controller->v_u, &controller->v_v, &controller->v_w); //inverse dq0 transform on voltages
00245        controller->current_sector = ((controller->i_a>0)<<2)|((controller->i_b>0)<<1)|(controller->i_c>0);
00246        svm(controller->v_bus, controller->v_u, controller->v_v, controller->v_w, controller->current_sector, &controller->dtc_u, &controller->dtc_v, &controller->dtc_w); //space vector modulation
00247        
00248        
00249         
00250 
00251        if(PHASE_ORDER){                                                         // Check which phase order to use, 
00252             TIM1->CCR3 = (PWM_ARR)*(1.0f-controller->dtc_u);                        // Write duty cycles
00253             TIM1->CCR2 = (PWM_ARR)*(1.0f-controller->dtc_v);
00254             TIM1->CCR1 = (PWM_ARR)*(1.0f-controller->dtc_w);
00255         }
00256         else{
00257             TIM1->CCR3 = (PWM_ARR)*(1.0f-controller->dtc_u);
00258             TIM1->CCR1 = (PWM_ARR)*(1.0f-controller->dtc_v);
00259             TIM1->CCR2 =  (PWM_ARR)*(1.0f-controller->dtc_w);
00260         }
00261 
00262        controller->theta_elec = theta;                                          
00263        
00264     }
00265     
00266     
00267 void torque_control(ControllerStruct *controller){
00268     float torque_ref = controller->kp*(controller->p_des - controller->theta_mech) + controller->t_ff + controller->kd*(controller->v_des - controller->dtheta_mech);
00269     //float torque_ref = -.1*(controller->p_des - controller->theta_mech);
00270     controller->i_q_ref = torque_ref/KT_OUT;    
00271     controller->i_d_ref = 0.0f;
00272     }
00273