BLDC motor driver
Dependencies: mbed-dev-f303 FastPWM3
Calibration/calibration.cpp
- Committer:
- benkatz
- Date:
- 2018-06-27
- Revision:
- 45:26801179208e
- Parent:
- 44:8040fa2fcb0d
- Child:
- 46:2d4b1dafcfe3
File content as of revision 45:26801179208e:
/// Calibration procedures for determining position sensor offset, /// phase ordering, and position sensor linearization /// #include "calibration.h" #include "foc.h" #include "PreferenceWriter.h" #include "user_config.h" #include "motor_config.h" #include "current_controller_config.h" void order_phases(PositionSensor *ps, GPIOStruct *gpio, ControllerStruct *controller, PreferenceWriter *prefs){ ///Checks phase order, to ensure that positive Q current produces ///torque in the positive direction wrt the position sensor. printf("\n\r Checking phase ordering\n\r"); float theta_ref = 0; float theta_actual = 0; float v_d = .05f; //Put all volts on the D-Axis float v_q = 0.0f; float v_u, v_v, v_w = 0; float dtc_u, dtc_v, dtc_w = .5f; int sample_counter = 0; ///Set voltage angle to zero, wait for rotor position to settle abc(theta_ref, v_d, v_q, &v_u, &v_v, &v_w); //inverse dq0 transform on voltages svm(1.0, v_u, v_v, v_w, &dtc_u, &dtc_v, &dtc_w); //space vector modulation for(int i = 0; i<20000; i++){ TIM1->CCR3 = (PWM_ARR>>1)*(1.0f-dtc_u); // Set duty cycles TIM1->CCR2 = (PWM_ARR>>1)*(1.0f-dtc_v); TIM1->CCR1 = (PWM_ARR>>1)*(1.0f-dtc_w); wait_us(100); } //ps->ZeroPosition(); ps->Sample(); wait_us(1000); //float theta_start = ps->GetMechPositionFixed(); //get initial rotor position float theta_start; controller->i_b = I_SCALE*(float)(controller->adc2_raw - controller->adc2_offset); //Calculate phase currents from ADC readings controller->i_c = I_SCALE*(float)(controller->adc1_raw - controller->adc1_offset); controller->i_a = -controller->i_b - controller->i_c; dq0(controller->theta_elec, controller->i_a, controller->i_b, controller->i_c, &controller->i_d, &controller->i_q); //dq0 transform on currents float current = sqrt(pow(controller->i_d, 2) + pow(controller->i_q, 2)); printf("\n\rCurrent\n\r"); printf("%f %f %f\n\r\n\r", controller->i_d, controller->i_q, current); /// Rotate voltage angle while(theta_ref < 4*PI){ //rotate for 2 electrical cycles abc(theta_ref, v_d, v_q, &v_u, &v_v, &v_w); //inverse dq0 transform on voltages svm(1.0, v_u, v_v, v_w, &dtc_u, &dtc_v, &dtc_w); //space vector modulation wait_us(100); TIM1->CCR3 = (PWM_ARR>>1)*(1.0f-dtc_u); //Set duty cycles TIM1->CCR2 = (PWM_ARR>>1)*(1.0f-dtc_v); TIM1->CCR1 = (PWM_ARR>>1)*(1.0f-dtc_w); ps->Sample(); //sample position sensor theta_actual = ps->GetMechPositionFixed(); if(theta_ref==0){theta_start = theta_actual;} if(sample_counter > 200){ sample_counter = 0 ; printf("%.4f %.4f\n\r", theta_ref/(NPP), theta_actual); } sample_counter++; theta_ref += 0.001f; } float theta_end = ps->GetMechPositionFixed(); int direction = (theta_end - theta_start)>0; printf("Theta Start: %f Theta End: %f\n\r", theta_start, theta_end); printf("Direction: %d\n\r", direction); if(direction){printf("Phasing correct\n\r");} else if(!direction){printf("Phasing incorrect. Swapping phases V and W\n\r");} PHASE_ORDER = direction; } void calibrate(PositionSensor *ps, GPIOStruct *gpio, ControllerStruct *controller, PreferenceWriter *prefs){ /// Measures the electrical angle offset of the position sensor /// and (in the future) corrects nonlinearity due to position sensor eccentricity printf("Starting calibration procedure\n\r"); const int n = 128*NPP; // number of positions to be sampled per mechanical rotation. Multiple of NPP for filtering reasons (see later) const int n2 = 50; // increments between saved samples (for smoothing motion) float delta = 2*PI*NPP/(n*n2); // change in angle between samples float error_f[n] = {0}; // error vector rotating forwards float error_b[n] = {0}; // error vector rotating backwards const int n_lut = 128; int lut[n_lut]= {0}; // clear any old lookup table before starting. ps->WriteLUT(lut); int raw_f[n] = {0}; int raw_b[n] = {0}; float theta_ref = 0; float theta_actual = 0; float v_d = .05f; // Put volts on the D-Axis float v_q = 0.0f; float v_u, v_v, v_w = 0; float dtc_u, dtc_v, dtc_w = .5f; ///Set voltage angle to zero, wait for rotor position to settle abc(theta_ref, v_d, v_q, &v_u, &v_v, &v_w); // inverse dq0 transform on voltages svm(1.0, v_u, v_v, v_w, &dtc_u, &dtc_v, &dtc_w); // space vector modulation for(int i = 0; i<40000; i++){ TIM1->CCR3 = (PWM_ARR>>1)*(1.0f-dtc_u); // Set duty cycles if(PHASE_ORDER){ TIM1->CCR2 = (PWM_ARR>>1)*(1.0f-dtc_v); TIM1->CCR1 = (PWM_ARR>>1)*(1.0f-dtc_w); } else{ TIM1->CCR1 = (PWM_ARR>>1)*(1.0f-dtc_v); TIM1->CCR2 = (PWM_ARR>>1)*(1.0f-dtc_w); } wait_us(100); } ps->Sample(); controller->i_b = I_SCALE*(float)(controller->adc2_raw - controller->adc2_offset); //Calculate phase currents from ADC readings controller->i_c = I_SCALE*(float)(controller->adc1_raw - controller->adc1_offset); controller->i_a = -controller->i_b - controller->i_c; dq0(controller->theta_elec, controller->i_a, controller->i_b, controller->i_c, &controller->i_d, &controller->i_q); //dq0 transform on currents float current = sqrt(pow(controller->i_d, 2) + pow(controller->i_q, 2)); printf(" Current Angle : Rotor Angle : Raw Encoder \n\r\n\r"); for(int i = 0; i<n; i++){ // rotate forwards for(int j = 0; j<n2; j++){ theta_ref += delta; abc(theta_ref, v_d, v_q, &v_u, &v_v, &v_w); // inverse dq0 transform on voltages svm(1.0, v_u, v_v, v_w, &dtc_u, &dtc_v, &dtc_w); // space vector modulation TIM1->CCR3 = (PWM_ARR>>1)*(1.0f-dtc_u); if(PHASE_ORDER){ // Check phase ordering TIM1->CCR2 = (PWM_ARR>>1)*(1.0f-dtc_v); // Set duty cycles TIM1->CCR1 = (PWM_ARR>>1)*(1.0f-dtc_w); } else{ TIM1->CCR1 = (PWM_ARR>>1)*(1.0f-dtc_v); TIM1->CCR2 = (PWM_ARR>>1)*(1.0f-dtc_w); } wait_us(100); ps->Sample(); } ps->Sample(); theta_actual = ps->GetMechPositionFixed(); error_f[i] = theta_ref/NPP - theta_actual; raw_f[i] = ps->GetRawPosition(); printf("%.4f %.4f %d\n\r", theta_ref/(NPP), theta_actual, raw_f[i]); //theta_ref += delta; } for(int i = 0; i<n; i++){ // rotate backwards for(int j = 0; j<n2; j++){ theta_ref -= delta; abc(theta_ref, v_d, v_q, &v_u, &v_v, &v_w); // inverse dq0 transform on voltages svm(1.0, v_u, v_v, v_w, &dtc_u, &dtc_v, &dtc_w); // space vector modulation TIM1->CCR3 = (PWM_ARR>>1)*(1.0f-dtc_u); if(PHASE_ORDER){ TIM1->CCR2 = (PWM_ARR>>1)*(1.0f-dtc_v); TIM1->CCR1 = (PWM_ARR>>1)*(1.0f-dtc_w); } else{ TIM1->CCR1 = (PWM_ARR>>1)*(1.0f-dtc_v); TIM1->CCR2 = (PWM_ARR>>1)*(1.0f-dtc_w); } wait_us(100); ps->Sample(); } ps->Sample(); // sample position sensor theta_actual = ps->GetMechPositionFixed(); // get mechanical position error_b[i] = theta_ref/NPP - theta_actual; raw_b[i] = ps->GetRawPosition(); printf("%.4f %.4f %d\n\r", theta_ref/(NPP), theta_actual, raw_b[i]); //theta_ref -= delta; } float offset = 0; for(int i = 0; i<n; i++){ offset += (error_f[i] + error_b[n-1-i])/(2.0f*n); // calclate average position sensor offset } offset = fmod(offset*NPP, 2*PI); // convert mechanical angle to electrical angle ps->SetElecOffset(offset); // Set position sensor offset __float_reg[0] = offset; E_OFFSET = offset; /// Perform filtering to linearize position sensor eccentricity /// FIR n-sample average, where n = number of samples in one electrical cycle /// This filter has zero gain at electrical frequency and all integer multiples /// So cogging effects should be completely filtered out. float error[n] = {0}; const int window = 128; float error_filt[n] = {0}; float cogging_current[window] = {0}; float mean = 0; for (int i = 0; i<n; i++){ //Average the forward and back directions error[i] = 0.5f*(error_f[i] + error_b[n-i-1]); } for (int i = 0; i<n; i++){ for(int j = 0; j<window; j++){ int ind = -window/2 + j + i; // Indexes from -window/2 to + window/2 if(ind<0){ ind += n;} // Moving average wraps around else if(ind > n-1) { ind -= n;} error_filt[i] += error[ind]/(float)window; } if(i<window){ cogging_current[i] = current*sinf((error[i] - error_filt[i])*NPP); } //printf("%.4f %4f %.4f %.4f\n\r", error[i], error_filt[i], error_f[i], error_b[i]); mean += error_filt[i]/n; } int raw_offset = (raw_f[0] + raw_b[n-1])/2; //Insensitive to errors in this direction, so 2 points is plenty printf("\n\r Encoder non-linearity compensation table\n\r"); printf(" Sample Number : Lookup Index : Lookup Value : Cogging Current Lookup\n\r\n\r"); for (int i = 0; i<n_lut; i++){ // build lookup table int ind = (raw_offset>>7) + i; if(ind > (n_lut-1)){ ind -= n_lut; } lut[ind] = (int) ((error_filt[i*NPP] - mean)*(float)(ps->GetCPR())/(2.0f*PI)); printf("%d %d %d %f\n\r", i, ind, lut[ind], cogging_current[i]); wait(.001); } ps->WriteLUT(lut); // write lookup table to position sensor object //memcpy(controller->cogging, cogging_current, sizeof(controller->cogging)); //compensation doesn't actually work yet.... memcpy(&ENCODER_LUT, lut, sizeof(lut)); // copy the lookup table to the flash array printf("\n\rEncoder Electrical Offset (rad) %f\n\r", offset); if (!prefs->ready()) prefs->open(); prefs->flush(); // write offset and lookup table to flash prefs->close(); }