rusefi
/
bldc
mirror of https://github.com/rusefi/bldc.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Correction of inductance measurement. Should only impact motors with high LdLq difference. 

motor->m_hfi.buffer now contains inverse of inductance
Rotating HFI starts rotating from alpha direction
This commit is contained in:
ElwinBoots 2024-07-19 22:14:20 +02:00
parent 6bfcd96f6d
commit 067393c226
1 changed files with 47 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

68
motor/mcpwm_foc.c
View File

@ -1430,8 +1430,14 @@ float mcpwm_foc_get_est_res(void) {
// NOTE: Requires the regular HFI sensor mode to run // NOTE: Requires the regular HFI sensor mode to run
float mcpwm_foc_get_est_ind(void) { float mcpwm_foc_get_est_ind(void) {
float real_bin0, imag_bin0; float real_bin0, imag_bin0;
get_motor_now()->m_hfi.fft_bin0_func((float*)get_motor_now()->m_hfi.buffer, &real_bin0, &imag_bin0); float real_bin2, imag_bin2;
return real_bin0; get_motor_now()->m_hfi.fft_bin0_func((float*)get_motor_now()->m_hfi.buffer, &real_bin0, &imag_bin0); // real_bin0 contains the average of the inverse of the inductance
get_motor_now()->m_hfi.fft_bin0_func((float*)get_motor_now()->m_hfi.buffer, &real_bin2, &imag_bin2); // real_bin2 (cosine) and imag_bin2 (sine) contain the magnitude of the measured 2nd harmonic. Note: dual sided and length normalized FFT, so signal magnitude is twice the bin value.
float offset = real_bin0;
float amplitude = NORM2_f(real_bin2, imag_bin2) * 2.0;
float Ld_est = 1.0 / (offset + amplitude);
float Lq_est = 1.0 / (offset - amplitude);
return (Ld_est + Lq_est) / 2.0;
} }
/** /**
@ -1944,15 +1950,26 @@ int mcpwm_foc_measure_inductance(float duty, int samples, float *curr, float *ld
float real_bin2, imag_bin2; float real_bin2, imag_bin2;
float real_bin0_i, imag_bin0_i; float real_bin0_i, imag_bin0_i;
motor->m_hfi.fft_bin0_func((float*)motor->m_hfi.buffer, &real_bin0, &imag_bin0); motor->m_hfi.fft_bin0_func((float*)motor->m_hfi.buffer, &real_bin0, &imag_bin0); // real_bin0 contains the average of the inverse of the inductance
motor->m_hfi.fft_bin2_func((float*)motor->m_hfi.buffer, &real_bin2, &imag_bin2); motor->m_hfi.fft_bin2_func((float*)motor->m_hfi.buffer, &real_bin2, &imag_bin2); // real_bin2 (cosine) and imag_bin2 (sine) contain the magnitude of the measured 2nd harmonic. Note: dual sided and length normalized FFT, so signal magnitude is twice the bin value.
motor->m_hfi.fft_bin0_func((float*)motor->m_hfi.buffer_current, &real_bin0_i, &imag_bin0_i); motor->m_hfi.fft_bin0_func((float*)motor->m_hfi.buffer_current, &real_bin0_i, &imag_bin0_i); // real_bin0_i contains the average delta current
l_sum += real_bin0; //l_sum += real_bin0;
i_sum += real_bin0_i; //i_sum += real_bin0_i;
// See https://vesc-project.com/comment/8338#comment-8338 // See https://vesc-project.com/comment/8338#comment-8338
ld_lq_diff_sum += 4.0 * NORM2_f(real_bin2, imag_bin2); //ld_lq_diff_sum += 4.0 * NORM2_f(real_bin2, imag_bin2);
// Above was an approximation that is only valid for motors with not too much LdLq difference. Below is correct (assuming Ld < Lq).
float offset = real_bin0;
float amplitude = NORM2_f(real_bin2, imag_bin2) * 2.0;
float Ld_est = 1.0 / (offset + amplitude);
float Lq_est = 1.0 / (offset - amplitude);
l_sum += (Ld_est + Lq_est) / 2.0;
ld_lq_diff_sum += (Lq_est - Ld_est);
i_sum += real_bin0_i;
iterations++; iterations++;
} }
@ -4024,7 +4041,7 @@ static void hfi_update(volatile motor_all_state_t *motor, float dt) {
angle_bin_1 += M_PI / 1.7; // Why 1.7?? angle_bin_1 += M_PI / 1.7; // Why 1.7??
utils_norm_angle_rad(&angle_bin_1); utils_norm_angle_rad(&angle_bin_1);
float mag_bin_2 = NORM2_f(imag_bin2, real_bin2); //float mag_bin_2 = NORM2_f(imag_bin2, real_bin2);
float angle_bin_2 = -utils_fast_atan2(imag_bin2, real_bin2) / 2.0; float angle_bin_2 = -utils_fast_atan2(imag_bin2, real_bin2) / 2.0;
// Assuming this thread is much faster than it takes to fill the HFI buffer completely, // Assuming this thread is much faster than it takes to fill the HFI buffer completely,
@ -4080,6 +4097,13 @@ static void hfi_update(volatile motor_all_state_t *motor, float dt) {
float real_bin0, imag_bin0; float real_bin0, imag_bin0;
motor->m_hfi.fft_bin0_func((float*)motor->m_hfi.buffer, &real_bin0, &imag_bin0); motor->m_hfi.fft_bin0_func((float*)motor->m_hfi.buffer, &real_bin0, &imag_bin0);
float offset = real_bin0;
float amplitude = NORM2_f(real_bin2, imag_bin2) * 2.0;
float Ld_est = 1.0 / (offset + amplitude);
float Lq_est = 1.0 / (offset - amplitude);
float L_est = (Ld_est + Lq_est) / 2.0;
float ld_lq_diff = (Lq_est - Ld_est);
commands_plot_set_graph(0); commands_plot_set_graph(0);
commands_send_plot_points(motor->m_hfi_plot_sample, motor->m_hfi.angle); commands_send_plot_points(motor->m_hfi_plot_sample, motor->m_hfi.angle);
@ -4088,13 +4112,13 @@ static void hfi_update(volatile motor_all_state_t *motor, float dt) {
commands_send_plot_points(motor->m_hfi_plot_sample, angle_bin_1); commands_send_plot_points(motor->m_hfi_plot_sample, angle_bin_1);
commands_plot_set_graph(2); commands_plot_set_graph(2);
commands_send_plot_points(motor->m_hfi_plot_sample, 2.0 * mag_bin_2 * 1e6); commands_send_plot_points(motor->m_hfi_plot_sample, ld_lq_diff * 1e6);
commands_plot_set_graph(3); commands_plot_set_graph(3);
commands_send_plot_points(motor->m_hfi_plot_sample, 2.0 * mag_bin_1 * 1e6); commands_send_plot_points(motor->m_hfi_plot_sample, (0.5 / mag_bin_1) * 1e6);
commands_plot_set_graph(4); commands_plot_set_graph(4);
commands_send_plot_points(motor->m_hfi_plot_sample, real_bin0 * 1e6); commands_send_plot_points(motor->m_hfi_plot_sample, L_est * 1e6);
// commands_plot_set_graph(0); // commands_plot_set_graph(0);
// commands_send_plot_points(motor->m_hfi_plot_sample, motor->m_pll_speed); // commands_send_plot_points(motor->m_hfi_plot_sample, motor->m_pll_speed);
@ -4581,14 +4605,14 @@ static void control_current(motor_all_state_t *motor, float dt) {
} }
} else { } else {
if (motor->m_hfi.is_samp_n) { if (motor->m_hfi.is_samp_n) {
float sample_now = (utils_tab_sin_32_1[motor->m_hfi.ind * motor->m_hfi.table_fact] * state_m->i_alpha - float sample_now = (utils_tab_cos_32_1[motor->m_hfi.ind * motor->m_hfi.table_fact] * state_m->i_alpha +
utils_tab_cos_32_1[motor->m_hfi.ind * motor->m_hfi.table_fact] * state_m->i_beta); utils_tab_sin_32_1[motor->m_hfi.ind * motor->m_hfi.table_fact] * state_m->i_beta);
float di = (sample_now - motor->m_hfi.prev_sample); float di = (sample_now - motor->m_hfi.prev_sample);
motor->m_hfi.buffer_current[motor->m_hfi.ind] = di; motor->m_hfi.buffer_current[motor->m_hfi.ind] = di;
if (di > 0.01) { if (di > 0.01) {
motor->m_hfi.buffer[motor->m_hfi.ind] = hfi_voltage / (conf_now->foc_f_zv * di); motor->m_hfi.buffer[motor->m_hfi.ind] = (conf_now->foc_f_zv * di) / hfi_voltage; //Changed to inverse of inductance. This is what is needed for the FFT, not the inductance itself. This is because the measurement has a dc offset, which will leak into other bins when the inverse is takes first.
} }
motor->m_hfi.ind++; motor->m_hfi.ind++;
@ -4597,14 +4621,14 @@ static void control_current(motor_all_state_t *motor, float dt) {
motor->m_hfi.ready = true; motor->m_hfi.ready = true;
} }
mod_alpha_v7 += hfi_voltage * utils_tab_sin_32_1[motor->m_hfi.ind * motor->m_hfi.table_fact] * voltage_normalize; mod_alpha_v7 += hfi_voltage * utils_tab_cos_32_1[motor->m_hfi.ind * motor->m_hfi.table_fact] * voltage_normalize;
mod_beta_v7 -= hfi_voltage * utils_tab_cos_32_1[motor->m_hfi.ind * motor->m_hfi.table_fact] * voltage_normalize; mod_beta_v7 += hfi_voltage * utils_tab_sin_32_1[motor->m_hfi.ind * motor->m_hfi.table_fact] * voltage_normalize;
} else { } else {
motor->m_hfi.prev_sample = utils_tab_sin_32_1[motor->m_hfi.ind * motor->m_hfi.table_fact] * state_m->i_alpha - motor->m_hfi.prev_sample = utils_tab_cos_32_1[motor->m_hfi.ind * motor->m_hfi.table_fact] * state_m->i_alpha +
utils_tab_cos_32_1[motor->m_hfi.ind * motor->m_hfi.table_fact] * state_m->i_beta; utils_tab_sin_32_1[motor->m_hfi.ind * motor->m_hfi.table_fact] * state_m->i_beta;
mod_alpha_v7 -= hfi_voltage * utils_tab_sin_32_1[motor->m_hfi.ind * motor->m_hfi.table_fact] * voltage_normalize; mod_alpha_v7 -= hfi_voltage * utils_tab_cos_32_1[motor->m_hfi.ind * motor->m_hfi.table_fact] * voltage_normalize;
mod_beta_v7 += hfi_voltage * utils_tab_cos_32_1[motor->m_hfi.ind * motor->m_hfi.table_fact] * voltage_normalize; mod_beta_v7 -= hfi_voltage * utils_tab_sin_32_1[motor->m_hfi.ind * motor->m_hfi.table_fact] * voltage_normalize;
} }
} }
@ -4630,7 +4654,7 @@ static void control_current(motor_all_state_t *motor, float dt) {
(uint32_t*)&motor->m_duty1_next, (uint32_t*)&motor->m_duty1_next,
(uint32_t*)&motor->m_duty2_next, (uint32_t*)&motor->m_duty2_next,
(uint32_t*)&motor->m_duty3_next, (uint32_t*)&motor->m_duty3_next,
(uint32_t*)&state_m->svm_sector); (uint32_t*)&state_m->svm_sector); //svm_sector already gettings written here. Seems incorrect since it will only be used in the next update, but svm_sector seems unused so no issue.
motor->m_duty_next_set = true; motor->m_duty_next_set = true;
} }
} else { } else {