Dear team:
My client refers to the theoretical introduction of Solarlib.pdf in the TIDM-02008 project:
Simulink simulation parameters:
TTPLPFC_AC_FREQ: 50Hz, TTPLPFC_CONTROL_ISR_FREQUENCY, lpf_b0 and lpf_b1 parameters are consistent with the parameters used by TIDM-02008.
Simulink simulation results: input an AC signal with a frequency of 51Hz (a frequency that may appear in a 50Hz AC grid), and see if the waveform can be locked, and it is found that the fo output frequency and q axis cannot be stabilized.
function [sin_a,cos_a,fo_out,Q_out] = fcn(acValue,acFreq,isrFrequency,isrFrequencyMAX,lpf_b0,lpf_b1) persistent sine; if isempty(sine) sine = 0.0; end sin_a = sine; persistent cosine; if isempty(cosine) cosine = 0.0; end cos_a = cosine; persistent cnt; if isempty(cnt) cnt = 0.0; end persistent fn; if isempty(fn) fn = acFreq; end persistent delta_t; if isempty(delta_t) delta_t = 1.0/isrFrequency; end persistent osg_coeff_osg_k; if isempty(osg_coeff_osg_k) osg_coeff_osg_k = 0.5; end persistent osg_coeff_osg_x; if isempty(osg_coeff_osg_x) wn = 2.0 * 3.14159265 * fn; osg_coeff_osg_x = 2.0 * osg_coeff_osg_k * wn * delta_t; end persistent osg_coeff_osg_y; if isempty(osg_coeff_osg_y) wn = 2.0 * 3.14159265 * fn; osg_coeff_osg_y = wn * delta_t * wn * delta_t; end persistent osg_coeff_osg_b0; if isempty(osg_coeff_osg_b0) osg_coeff_osg_b0 = osg_coeff_osg_x / (osg_coeff_osg_x + osg_coeff_osg_y + 4.0); end persistent osg_coeff_osg_b2; if isempty(osg_coeff_osg_b2) osg_coeff_osg_b2 = -osg_coeff_osg_x / (osg_coeff_osg_x + osg_coeff_osg_y + 4.0); end persistent osg_coeff_osg_a1; if isempty(osg_coeff_osg_a1) osg_coeff_osg_a1 = 2 * (4.0 - osg_coeff_osg_y) / (osg_coeff_osg_x + osg_coeff_osg_y + 4.0); end persistent osg_coeff_osg_a2; if isempty(osg_coeff_osg_a2) osg_coeff_osg_a2 = (osg_coeff_osg_x - osg_coeff_osg_y - 4) / (osg_coeff_osg_x + osg_coeff_osg_y + 4.0); end persistent osg_coeff_osg_qb0; if isempty(osg_coeff_osg_qb0) osg_coeff_osg_qb0 = osg_coeff_osg_k * osg_coeff_osg_y / (osg_coeff_osg_x + osg_coeff_osg_y + 4.0); end persistent osg_coeff_osg_qb1; if isempty(osg_coeff_osg_qb1) osg_coeff_osg_qb1 = 2 * osg_coeff_osg_k * osg_coeff_osg_y / (osg_coeff_osg_x + osg_coeff_osg_y + 4.0); end persistent osg_coeff_osg_qb2; if isempty(osg_coeff_osg_qb2) osg_coeff_osg_qb2 = osg_coeff_osg_k * osg_coeff_osg_y / (osg_coeff_osg_x + osg_coeff_osg_y + 4.0); end persistent lpf_coeff_b0; if isempty(lpf_coeff_b0) lpf_coeff_b0 = lpf_b0; end persistent lpf_coeff_b1; if isempty(lpf_coeff_b1) lpf_coeff_b1 = lpf_b1; end persistent u_0; if isempty(u_0) u_0 = 0.0; end persistent u_1; if isempty(u_1) u_1 = 0.0; end persistent u_2; if isempty(u_2) u_2 = 0.0; end persistent osg_u_0; if isempty(osg_u_0) osg_u_0 = 0.0; end persistent osg_u_1; if isempty(osg_u_1) osg_u_1 = 0.0; end persistent osg_u_2; if isempty(osg_u_2) osg_u_2 = 0.0; end persistent osg_qu_0; if isempty(osg_qu_0) osg_qu_0 = 0.0; end persistent osg_qu_1; if isempty(osg_qu_1) osg_qu_1 = 0.0; end persistent osg_qu_2; if isempty(osg_qu_2) osg_qu_2 = 0.0; end persistent u_Q_0; if isempty(u_Q_0) u_Q_0 = 0.0; end Q_out = u_Q_0; persistent u_Q_1; if isempty(u_Q_1) u_Q_1 = 0.0; end persistent u_D_0; if isempty(u_D_0) u_D_0 = 0.0; end persistent ylf_0; if isempty(ylf_0) ylf_0 = 0.0; end persistent ylf_1; if isempty(ylf_1) ylf_1 = 0.0; end persistent fo; if isempty(fo) fo = 0.0; end fo_out = fo; persistent theta; if isempty(theta) theta = 0.0; end if cnt >= isrFrequencyMAX cnt = cnt - isrFrequencyMAX; % Update the spll_obj->u[0] with the grid value u_0 = acValue; % Orthogonal Signal Generator osg_u_0 = osg_coeff_osg_b0 * (u_0 - u_2) + osg_coeff_osg_a1 * osg_u_1 + osg_coeff_osg_a2 * osg_u_2; osg_u_2 = osg_u_1; osg_u_1 = osg_u_0; osg_qu_0 = osg_coeff_osg_qb0 * u_0 + osg_coeff_osg_qb1 * u_1 + osg_coeff_osg_qb2 * u_2 + osg_coeff_osg_a1 * osg_qu_1 + osg_coeff_osg_a2 * osg_qu_2; osg_qu_2 = osg_qu_1; osg_qu_1 = osg_qu_0; u_2 = u_1; u_1 = u_0; % Park Transform from alpha beta to d-q axis u_Q_0 = cosine * osg_u_0 + sine * osg_qu_0; u_D_0 = cosine * osg_qu_0 - sine * osg_u_0; % Loop Filter ylf_0 = ylf_1 + lpf_coeff_b0 * u_Q_0 + lpf_coeff_b1 * u_Q_1; ylf_1 = ylf_0; u_Q_1 = u_Q_0; fo = fn + ylf_0; theta = theta + (fo * delta_t) * (2.0 * 3.1415926); if theta < 0 theta = 0; end if(theta > (2.0 * 3.1415926)) theta = theta - (2.0 * 3.1415926); %theta = 0; end sin_a = sin(theta); cos_a = cos(theta); sine = sin_a; cosine = cos_a; end cnt = cnt + 1;
simulink simulation result q-axis output:
Output frequency:
May I ask why this is caused?
In the table for calculating lpf_b0 and lpf_b1, what does the specific meaning of "Error Band" mean?
Best regards