TIDM-02008: 使用的软件锁相环在仿真过程中无法锁定一直振荡，无法稳定的问题

使用TIDM-02008项目中软件锁相环的算法，该算法Solarlib.pdf中的理论介绍

simulink仿真参数：TTPLPFC_AC_FREQ为50Hz，TTPLPFC_CONTROL_ISR_FREQUENCY，lpf_b0和lpf_b1参数与TIDM-02008所使用的参数一致。

simulink仿真过程：输入51Hz频率的交流信号（50Hz交流电网中有可能出现的频率），看波形图是否能锁定，发现fo输出频率和q轴无法稳定下来。

simulink仿真内容：

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 >= isrFrequencyMAXcnt = cnt - isrFrequencyMAX;% Update the spll_obj->u[0] with the grid valueu_0 = acValue;% Orthogonal Signal Generatorosg_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 axisu_Q_0 = cosine * osg_u_0 + sine * osg_qu_0;u_D_0 = cosine * osg_qu_0 - sine * osg_u_0;% Loop Filterylf_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 < 0theta = 0;endif(theta > (2.0 * 3.1415926))theta = theta - (2.0 * 3.1415926);%theta = 0;endsin_a = sin(theta);cos_a = cos(theta);sine = sin_a;cosine = cos_a;
end

cnt = cnt + 1;

simulink仿真结果如下

q轴输出

输出频率

为什么呢？是lpf_b0和lpf_b1参数不对吗？计算lpf_b0和lpf_b1表格中“Error Band”的具体含义是指什么意思？本人研究一段时间了，非常期待您们的回复！

Green Deng：

你好，这个问题为你升级到英文E2E论坛了，还请留意以下帖子回复：e2e.ti.com/…/tidm-02008-the-software-phase-locked-loop-cannot-be-locked-during-the-simulation-process-and-it-keeps-oscillating

,

m gh：

非常感谢