foc.cpp

00001 #include "foc.h"
00002 #include "arm_math.h"
00003 
00004 void abc( float theta, float d, float q, float *a, float *b, float *c){
00005     /// Inverse DQ0 Transform ///
00006     ///Phase current amplitude = lengh of dq vector///
00007     ///i.e. iq = 1, id = 0, peak phase current of 1///
00008     float cf = arm_cos_f32(theta);
00009     float sf = arm_sin_f32(theta);
00010     
00011     *a = cf*d - sf*q;                // Faster Inverse DQ0 transform
00012     *b = (0.86602540378f*sf-.5f*cf)*d - (-0.86602540378f*cf-.5f*sf)*q;
00013     *c = (-0.86602540378f*sf-.5f*cf)*d - (0.86602540378f*cf-.5f*sf)*q;
00014     }
00015     
00016     
00017 void dq0(float theta, float a, float b, float c, float *d, float *q){
00018     /// DQ0 Transform ///
00019     ///Phase current amplitude = lengh of dq vector///
00020     ///i.e. iq = 1, id = 0, peak phase current of 1///
00021     
00022     float cf = arm_cos_f32(theta);
00023     float sf = arm_sin_f32(theta);
00024     
00025     *d = 0.6666667f*(cf*a + (0.86602540378f*sf-.5f*cf)*b + (-0.86602540378f*sf-.5f*cf)*c);   ///Faster DQ0 Transform
00026     *q = 0.6666667f*(-sf*a - (-0.86602540378f*cf-.5f*sf)*b - (0.86602540378f*cf-.5f*sf)*c);
00027        
00028     }
00029 
00030 void fast_dq0(float theta, float a, float b, float c, float *d, float *q) {
00031     float32_t sinVal;
00032     float32_t cosVal;
00033     arm_sin_cos_f32(theta, &sinVal, &cosVal);
00034     float32_t alpha;
00035     float32_t beta;
00036     arm_clarke_f32(a, b, &alpha, &beta);
00037     arm_park_f32(alpha, beta, d, q, sinVal, cosVal);
00038 }
00039 
00040 void fast_abc(float theta, float d, float q, float *a, float *b, float *c) {
00041     float32_t sinVal;
00042     float32_t cosVal;
00043     arm_sin_cos_f32(theta, &sinVal, &cosVal);
00044     float32_t alpha;
00045     float32_t beta;
00046     arm_inv_park_f32(d, q, &alpha, &beta, sinVal, cosVal);
00047     arm_inv_clarke_f32(alpha, beta, a, b);
00048     *c = -*a - *b;
00049 }
00050     
00051 void svm(float v_bus, float u, float v, float w, float *dtc_u, float *dtc_v, float *dtc_w){
00052     /// Space Vector Modulation ///
00053     // u,v,w amplitude = v_bus for full modulation depth
00054     
00055     float v_offset = (fminf3(u, v, w) + fmaxf3(u, v, w))*0.5f;
00056     
00057     *dtc_u = fminf(fmaxf(((u -v_offset)/v_bus + .5f), DTC_MIN), DTC_MAX);
00058     *dtc_v = fminf(fmaxf(((v -v_offset)/v_bus + .5f), DTC_MIN), DTC_MAX);
00059     *dtc_w = fminf(fmaxf(((w -v_offset)/v_bus + .5f), DTC_MIN), DTC_MAX); 
00060     }
00061 
00062 void linearize_dtc(float *dtc){
00063     /// linearizes the output of the inverter, which is not linear for small duty cycles ///
00064     float sgn = 1.0f-(2.0f * (*dtc < 0));
00065     if(abs(*dtc) >= .01f){
00066         *dtc = *dtc*.986f+.014f*sgn;
00067         }
00068     else{
00069         *dtc = 2.5f*(*dtc);
00070         }
00071     
00072     }
00073     
00074     
00075 void zero_current(int *offset_1, int *offset_2){                                // Measure zero-offset of the current sensors
00076     int adc1_offset = 0;
00077     int adc2_offset = 0;
00078     int n = 1024;
00079     for (int i = 0; i<n; i++){                                                  // Average n samples of the ADC
00080         TIM1->CCR3 = (PWM_ARR>>1)*(1.0f);                                               // Write duty cycles
00081         TIM1->CCR2 = (PWM_ARR>>1)*(1.0f);
00082         TIM1->CCR1 = (PWM_ARR>>1)*(1.0f);
00083         ADC1->CR2  |= 0x40000000;                                               // Begin sample and conversion
00084         wait_us(1000);
00085         adc2_offset += ADC2->DR;
00086         adc1_offset += ADC1->DR;
00087         }
00088     *offset_1 = adc1_offset/n;
00089     *offset_2 = adc2_offset/n;
00090     }
00091     
00092 void init_controller_params(ControllerStruct *controller){
00093     controller->ki_d = KI_D;
00094     controller->ki_q = KI_Q;
00095     controller->k_d = K_SCALE*I_BW;
00096     controller->k_q = K_SCALE*I_BW;
00097     controller->alpha = 1.0f - 1.0f/(1.0f - DT*I_BW*2.0f*PI);
00098     
00099     }
00100 
00101 void reset_foc(ControllerStruct *controller){
00102     TIM1->CCR3 = (PWM_ARR>>1)*(0.5f);
00103     TIM1->CCR1 = (PWM_ARR>>1)*(0.5f);
00104     TIM1->CCR2 = (PWM_ARR>>1)*(0.5f);
00105     controller->i_d_ref = 0;
00106     controller->i_q_ref = 0;
00107     controller->i_d = 0;
00108     controller->i_q = 0;
00109     controller->i_q_filt = 0;
00110     controller->q_int = 0;
00111     controller->d_int = 0;
00112     controller->v_q = 0;
00113     controller->v_d = 0;
00114 
00115     }
00116     
00117 void reset_observer(ObserverStruct *observer){
00118     observer->temperature = 25.0f;
00119     observer->resistance = .1f;
00120     }
00121     
00122 void limit_current_ref (ControllerStruct *controller){
00123     float i_q_max_limit = (0.5774f*controller->v_bus - controller->dtheta_elec*WB)/R_PHASE;
00124     float i_q_min_limit = (-0.5774f*controller->v_bus - controller->dtheta_elec*WB)/R_PHASE;
00125     controller->i_q_ref = fmaxf(fminf(i_q_max_limit, controller->i_q_ref), i_q_min_limit);
00126     }
00127 
00128 
00129 void commutate(ControllerStruct *controller, ObserverStruct *observer, GPIOStruct *gpio, float theta){
00130         
00131         /// Update observer estimates ///
00132         // Resistance observer //
00133         // Temperature Observer //
00134         float t_rise = (float)observer->temperature - 25.0f;
00135         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);
00136         float q_th_out = t_rise*R_TH;
00137         observer->temperature += INV_M_TH*DT*(q_th_in-q_th_out);
00138         
00139         observer->resistance = (controller->v_q - SQRT3*controller->dtheta_elec*(WB))/controller->i_q;
00140         //observer->resistance = controller->v_q/controller->i_q;
00141         if(isnan(observer->resistance)){observer->resistance = R_PHASE;}
00142         observer->temperature2 = (double)(25.0f + ((observer->resistance*6.0606f)-1.0f)*275.5f);
00143         double e = observer->temperature - observer->temperature2;
00144         observer->temperature -= .001*e;
00145         //printf("%.3f\n\r", e);
00146         
00147 
00148        /// Commutation Loop ///
00149        controller->loop_count ++;   
00150        if(PHASE_ORDER){                                                                          // Check current sensor ordering
00151            controller->i_b = I_SCALE*(float)(controller->adc2_raw - controller->adc2_offset);    // Calculate phase currents from ADC readings
00152            controller->i_c = I_SCALE*(float)(controller->adc1_raw - controller->adc1_offset);
00153            }
00154         else{
00155             controller->i_b = I_SCALE*(float)(controller->adc1_raw - controller->adc1_offset);    
00156            controller->i_c = I_SCALE*(float)(controller->adc2_raw - controller->adc2_offset);
00157            }
00158        controller->i_a = -controller->i_b - controller->i_c;       
00159        
00160         float c = arm_cos_f32(theta);
00161         float s = arm_sin_f32(theta);                           
00162        dq0(controller->theta_elec, controller->i_a, controller->i_b, controller->i_c, &controller->i_d, &controller->i_q);    //dq0 transform on currents
00163        //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
00164        //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);
00165         
00166         controller->i_q_filt = 0.95f*controller->i_q_filt + 0.05f*controller->i_q;
00167         controller->i_d_filt = 0.95f*controller->i_d_filt + 0.05f*controller->i_d;
00168         
00169         
00170         // Filter the current references to the desired closed-loop bandwidth
00171         controller->i_d_ref_filt = (1.0f-controller->alpha)*controller->i_d_ref_filt + controller->alpha*controller->i_d_ref;
00172         controller->i_q_ref_filt = (1.0f-controller->alpha)*controller->i_q_ref_filt + controller->alpha*controller->i_q_ref;
00173 
00174        
00175        /// Field Weakening ///
00176        
00177        controller->fw_int += .001f*(0.5f*OVERMODULATION*controller->v_bus - controller->v_ref);
00178        controller->fw_int = fmaxf(fminf(controller->fw_int, 0.0f), -I_FW_MAX);
00179        controller->i_d_ref = controller->fw_int;
00180        //float i_cmd_mag_sq = controller->i_d_ref*controller->i_d_ref + controller->i_q_ref*controller->i_q_ref;
00181        limit_norm(&controller->i_d_ref, &controller->i_q_ref, I_MAX);
00182        
00183        
00184        
00185        /// PI Controller ///
00186        float i_d_error = controller->i_d_ref - controller->i_d;
00187        float i_q_error = controller->i_q_ref - controller->i_q;//  + cogging_current;
00188        
00189        // Calculate feed-forward voltages //
00190        float v_d_ff = SQRT3*(1.0f*controller->i_d_ref*R_PHASE  - controller->dtheta_elec*L_Q*controller->i_q);   //feed-forward voltages
00191        float v_q_ff =  SQRT3*(1.0f*controller->i_q_ref*R_PHASE +  controller->dtheta_elec*(L_D*controller->i_d + 1.0f*WB));
00192        
00193        // Integrate Error //
00194        controller->d_int += controller->k_d*controller->ki_d*i_d_error;   
00195        controller->q_int += controller->k_q*controller->ki_q*i_q_error;
00196        
00197        controller->d_int = fmaxf(fminf(controller->d_int, OVERMODULATION*controller->v_bus), - OVERMODULATION*controller->v_bus);
00198        controller->q_int = fmaxf(fminf(controller->q_int, OVERMODULATION*controller->v_bus), - OVERMODULATION*controller->v_bus); 
00199        
00200        //limit_norm(&controller->d_int, &controller->q_int, OVERMODULATION*controller->v_bus);     
00201        controller->v_d = controller->k_d*i_d_error + controller->d_int ;//+ v_d_ff;  
00202        controller->v_q = controller->k_q*i_q_error + controller->q_int ;//+ v_q_ff; 
00203        
00204        controller->v_ref = sqrt(controller->v_d*controller->v_d + controller->v_q*controller->v_q);
00205        
00206        limit_norm(&controller->v_d, &controller->v_q, OVERMODULATION*controller->v_bus);       // Normalize voltage vector to lie within curcle of radius v_bus
00207        float dtc_d = controller->v_d/controller->v_bus;
00208        float dtc_q = controller->v_q/controller->v_bus;
00209        linearize_dtc(&dtc_d);
00210        linearize_dtc(&dtc_q);
00211        controller->v_d = dtc_d*controller->v_bus;
00212        controller->v_q = dtc_q*controller->v_bus;
00213        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
00214        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
00215 
00216        if(PHASE_ORDER){                                                         // Check which phase order to use, 
00217             TIM1->CCR3 = (PWM_ARR)*(1.0f-controller->dtc_u);                        // Write duty cycles
00218             TIM1->CCR2 = (PWM_ARR)*(1.0f-controller->dtc_v);
00219             TIM1->CCR1 = (PWM_ARR)*(1.0f-controller->dtc_w);
00220         }
00221         else{
00222             TIM1->CCR3 = (PWM_ARR)*(1.0f-controller->dtc_u);
00223             TIM1->CCR1 = (PWM_ARR)*(1.0f-controller->dtc_v);
00224             TIM1->CCR2 =  (PWM_ARR)*(1.0f-controller->dtc_w);
00225         }
00226 
00227        controller->theta_elec = theta;                                          
00228        
00229     }
00230     
00231     
00232 void torque_control(ControllerStruct *controller){
00233     float torque_ref = controller->kp*(controller->p_des - controller->theta_mech) + controller->t_ff + controller->kd*(controller->v_des - controller->dtheta_mech);
00234     //float torque_ref = -.1*(controller->p_des - controller->theta_mech);
00235     controller->i_q_ref = torque_ref/KT_OUT;    
00236     controller->i_d_ref = 0.0f;
00237     }
00238