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, 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     *dtc_u = fminf(fmaxf(((u -v_offset)/v_bus + .5f), DTC_MIN), DTC_MAX);
00039     *dtc_v = fminf(fmaxf(((v -v_offset)/v_bus + .5f), DTC_MIN), DTC_MAX);
00040     *dtc_w = fminf(fmaxf(((w -v_offset)/v_bus + .5f), DTC_MIN), DTC_MAX); 
00041     
00042     /*
00043     sinusoidal pwm
00044     *dtc_u = fminf(fmaxf((u/v_bus + .5f), DTC_MIN), DTC_MAX);
00045     *dtc_v = fminf(fmaxf((v/v_bus + .5f), DTC_MIN), DTC_MAX);
00046     *dtc_w = fminf(fmaxf((w/v_bus + .5f), DTC_MIN), DTC_MAX);
00047     */
00048      
00049     
00050     }
00051 
00052 void linearize_dtc(float *dtc){
00053     /// linearizes the output of the inverter, which is not linear for small duty cycles ///
00054     float sgn = 1.0f-(2.0f*(dtc<0));
00055     if(abs(*dtc) >= .01f){
00056         *dtc = *dtc*.986f+.014f*sgn;
00057         }
00058     else{
00059         *dtc = 2.5f*(*dtc);
00060         }
00061     
00062     }
00063     
00064     
00065 void zero_current(int *offset_1, int *offset_2){                                // Measure zero-offset of the current sensors
00066     int adc1_offset = 0;
00067     int adc2_offset = 0;
00068     int n = 1024;
00069     for (int i = 0; i<n; i++){                                                  // Average n samples of the ADC
00070         TIM1->CCR3 = (PWM_ARR>>1)*(1.0f);                                               // Write duty cycles
00071         TIM1->CCR2 = (PWM_ARR>>1)*(1.0f);
00072         TIM1->CCR1 = (PWM_ARR>>1)*(1.0f);
00073         ADC1->CR2  |= 0x40000000;                                               // Begin sample and conversion
00074         wait(.001);
00075         adc2_offset += ADC2->DR;
00076         adc1_offset += ADC1->DR;
00077         }
00078     *offset_1 = adc1_offset/n;
00079     *offset_2 = adc2_offset/n;
00080     }
00081     
00082 void init_controller_params(ControllerStruct *controller){
00083     controller->ki_d = KI_D;
00084     controller->ki_q = KI_Q;
00085     controller->k_d = K_SCALE*I_BW;
00086     controller->k_q = K_SCALE*I_BW;
00087     controller->alpha = 1.0f - 1.0f/(1.0f - DT*I_BW*2.0f*PI);
00088     
00089     }
00090 
00091 void reset_foc(ControllerStruct *controller){
00092     TIM1->CCR3 = (PWM_ARR>>1)*(0.5f);
00093     TIM1->CCR1 = (PWM_ARR>>1)*(0.5f);
00094     TIM1->CCR2 = (PWM_ARR>>1)*(0.5f);
00095     controller->i_d_ref = 0;
00096     controller->i_q_ref = 0;
00097     controller->i_d = 0;
00098     controller->i_q = 0;
00099     controller->i_q_filt = 0;
00100     controller->q_int = 0;
00101     controller->d_int = 0;
00102     controller->v_q = 0;
00103     controller->v_d = 0;
00104 
00105     }
00106     
00107 void reset_observer(ObserverStruct *observer){
00108     observer->temperature = 25.0f;
00109     observer->resistance = .1f;
00110     }
00111     
00112 void limit_current_ref (ControllerStruct *controller){
00113     float i_q_max_limit = (0.5774f*controller->v_bus - controller->dtheta_elec*WB)/R_PHASE;
00114     float i_q_min_limit = (-0.5774f*controller->v_bus - controller->dtheta_elec*WB)/R_PHASE;
00115     controller->i_q_ref = fmaxf(fminf(i_q_max_limit, controller->i_q_ref), i_q_min_limit);
00116     }
00117 
00118 
00119 void commutate(ControllerStruct *controller, ObserverStruct *observer, GPIOStruct *gpio, float theta){
00120         
00121         /// Update observer estimates ///
00122         // Resistance observer //
00123         // Temperature Observer //
00124         float t_rise = (float)observer->temperature - 25.0f;
00125         float q_th_in = (1.0f + .00393f*t_rise)*(controller->i_d*controller->i_d*R_PHASE*SQRT3 + controller->i_q*controller->i_q*R_PHASE*SQRT3);
00126         float q_th_out = t_rise*R_TH;
00127         observer->temperature += INV_M_TH*DT*(q_th_in-q_th_out);
00128         
00129         observer->resistance = (controller->v_q - SQRT3*controller->dtheta_elec*(WB))/controller->i_q;
00130         //observer->resistance = controller->v_q/controller->i_q;
00131         if(isnan(observer->resistance)){observer->resistance = R_PHASE;}
00132         observer->temperature2 = (double)(25.0f + ((observer->resistance*6.0606f)-1.0f)*275.5f);
00133         double e = observer->temperature - observer->temperature2;
00134         observer->temperature -= .001*e;
00135         //printf("%.3f\n\r", e);
00136         /*
00137         // Integrate the thermal model //
00138         delta_t = observer.temperature - T_AMBIENT;
00139         observer.qd_in = R_NOMINAL**(1.0f + .00393f*delta_t)*controller.i*controller.i;
00140         observer.qd_out = delta_t*R_TH;
00141         observer.temperature += DT*(observer.qd_in-observer.qd_out)/C_TH;
00142             
00143         // Estimate Resistance //
00144         observer.resistance = (controller.v_q - controller.omega*(L_D*controller.i_d + WB))/(controller.i_q);
00145         
00146         // Estimate Temperature from temp-co //
00147         observer.t_measured = ((T_AMBIENT + ((observer.resistance/R_NOMINAL) - 1.0f)*254.5f));
00148         
00149         // Update Observer with measured temperature //
00150         e = (float)observer.temperature - observer.temp_measured;
00151         //observer.temperature -= .0001f*e;
00152         // Calculate "trust" based on state //
00153         observer.trust = (1.0f - .004f*fminf(abs(controller.dtheta_elec), 250.0f)) * (.01f*(fminf(controller.current^2, 100.0f)));
00154         
00155         // Scale observer gain by "trust" //
00156         // .0001 is the default observer gain //
00157         observer.temperature -= observer.trust*.0001f*e;
00158         
00159         
00160         */    
00161        /// Commutation Loop ///
00162        controller->loop_count ++;   
00163        if(PHASE_ORDER){                                                                          // Check current sensor ordering
00164            controller->i_b = I_SCALE*(float)(controller->adc2_raw - controller->adc2_offset);    // Calculate phase currents from ADC readings
00165            controller->i_c = I_SCALE*(float)(controller->adc1_raw - controller->adc1_offset);
00166            }
00167         else{
00168             controller->i_b = I_SCALE*(float)(controller->adc1_raw - controller->adc1_offset);    
00169            controller->i_c = I_SCALE*(float)(controller->adc2_raw - controller->adc2_offset);
00170            }
00171        controller->i_a = -controller->i_b - controller->i_c;       
00172        
00173        float s = FastSin(theta); 
00174        float c = FastCos(theta);                            
00175        dq0(controller->theta_elec, controller->i_a, controller->i_b, controller->i_c, &controller->i_d, &controller->i_q);    //dq0 transform on currents
00176        //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
00177        //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);
00178         
00179         controller->i_q_filt = 0.95f*controller->i_q_filt + 0.05f*controller->i_q;
00180         controller->i_d_filt = 0.95f*controller->i_d_filt + 0.05f*controller->i_d;
00181         
00182         
00183         // Filter the current references to the desired closed-loop bandwidth
00184         controller->i_d_ref_filt = (1.0f-controller->alpha)*controller->i_d_ref_filt + controller->alpha*controller->i_d_ref;
00185         controller->i_q_ref_filt = (1.0f-controller->alpha)*controller->i_q_ref_filt + controller->alpha*controller->i_q_ref;
00186 
00187        
00188        /// Field Weakening ///
00189        
00190        controller->fw_int += .001f*(0.5f*OVERMODULATION*controller->v_bus - controller->v_ref);
00191        controller->fw_int = fmaxf(fminf(controller->fw_int, 0.0f), -I_FW_MAX);
00192        controller->i_d_ref = controller->fw_int;
00193        //float i_cmd_mag_sq = controller->i_d_ref*controller->i_d_ref + controller->i_q_ref*controller->i_q_ref;
00194        limit_norm(&controller->i_d_ref, &controller->i_q_ref, I_MAX);
00195        
00196        
00197        
00198        /// PI Controller ///
00199        float i_d_error = controller->i_d_ref - controller->i_d;
00200        float i_q_error = controller->i_q_ref - controller->i_q;//  + cogging_current;
00201        
00202        // Calculate feed-forward voltages //
00203        float v_d_ff = SQRT3*(1.0f*controller->i_d_ref*R_PHASE  - controller->dtheta_elec*L_Q*controller->i_q);   //feed-forward voltages
00204        float v_q_ff =  SQRT3*(1.0f*controller->i_q_ref*R_PHASE +  controller->dtheta_elec*(L_D*controller->i_d + 1.0f*WB));
00205        
00206        // Integrate Error //
00207        controller->d_int += controller->k_d*controller->ki_d*i_d_error;   
00208        controller->q_int += controller->k_q*controller->ki_q*i_q_error;
00209        
00210        controller->d_int = fmaxf(fminf(controller->d_int, OVERMODULATION*controller->v_bus), - OVERMODULATION*controller->v_bus);
00211        controller->q_int = fmaxf(fminf(controller->q_int, OVERMODULATION*controller->v_bus), - OVERMODULATION*controller->v_bus); 
00212        
00213        //limit_norm(&controller->d_int, &controller->q_int, OVERMODULATION*controller->v_bus);     
00214        controller->v_d = controller->k_d*i_d_error + controller->d_int ;//+ v_d_ff;  
00215        controller->v_q = controller->k_q*i_q_error + controller->q_int ;//+ v_q_ff; 
00216        
00217        controller->v_ref = sqrt(controller->v_d*controller->v_d + controller->v_q*controller->v_q);
00218        
00219        limit_norm(&controller->v_d, &controller->v_q, OVERMODULATION*controller->v_bus);       // Normalize voltage vector to lie within curcle of radius v_bus
00220        float dtc_d = controller->v_d/controller->v_bus;
00221        float dtc_q = controller->v_q/controller->v_bus;
00222        linearize_dtc(&dtc_d);
00223        linearize_dtc(&dtc_q);
00224        controller->v_d = dtc_d*controller->v_bus;
00225        controller->v_q = dtc_q*controller->v_bus;
00226        abc(controller->theta_elec + 0.0f*DT*controller->dtheta_elec, controller->v_d, controller->v_q, &controller->v_u, &controller->v_v, &controller->v_w); //inverse dq0 transform on voltages
00227        svm(controller->v_bus, controller->v_u, controller->v_v, controller->v_w, &controller->dtc_u, &controller->dtc_v, &controller->dtc_w); //space vector modulation
00228 
00229        if(PHASE_ORDER){                                                         // Check which phase order to use, 
00230             TIM1->CCR3 = (PWM_ARR)*(1.0f-controller->dtc_u);                        // Write duty cycles
00231             TIM1->CCR2 = (PWM_ARR)*(1.0f-controller->dtc_v);
00232             TIM1->CCR1 = (PWM_ARR)*(1.0f-controller->dtc_w);
00233         }
00234         else{
00235             TIM1->CCR3 = (PWM_ARR)*(1.0f-controller->dtc_u);
00236             TIM1->CCR1 = (PWM_ARR)*(1.0f-controller->dtc_v);
00237             TIM1->CCR2 =  (PWM_ARR)*(1.0f-controller->dtc_w);
00238         }
00239 
00240        controller->theta_elec = theta;                                          
00241        
00242     }
00243     
00244     
00245 void torque_control(ControllerStruct *controller){
00246     float torque_ref = controller->kp*(controller->p_des - controller->theta_mech) + controller->t_ff + controller->kd*(controller->v_des - controller->dtheta_mech);
00247     //float torque_ref = -.1*(controller->p_des - controller->theta_mech);
00248     controller->i_q_ref = torque_ref/KT_OUT;    
00249     controller->i_d_ref = 0.0f;
00250     }
00251