TI例程SPLL_3ph_DDSRF(解耦双同步坐标系软件锁相环)中LPF(低通滤波器)的离散方程不知道如何推导出来的，求解答?

程序中对应的离散方程

// Low pass filter //
//————————-//

spll_obj->y[1] = (spll_obj->d_p_decoupl*spll_obj->k1) – (spll_obj->y[0]*spll_obj->k2);
spll_obj->d_p_decoupl_lpf = spll_obj->y[1] + spll_obj->y[0];
spll_obj->y[0] = spll_obj->y[1];

Seven Han：

请问您使用的哪个芯片，哪个例程呢？

程序中对应的离散方程

// Low pass filter //
//————————-//

spll_obj->y[1] = (spll_obj->d_p_decoupl*spll_obj->k1) – (spll_obj->y[0]*spll_obj->k2);
spll_obj->d_p_decoupl_lpf = spll_obj->y[1] + spll_obj->y[0];
spll_obj->y[0] = spll_obj->y[1];

user3784592：

回复 Seven Han:

28335，例程在C:\TI\controlSUITE\libs\app_libs\solar\v1.2\float\source\SPLL_3ph_DDSRF_F

程序中对应的离散方程

// Low pass filter //
//————————-//

spll_obj->y[1] = (spll_obj->d_p_decoupl*spll_obj->k1) – (spll_obj->y[0]*spll_obj->k2);
spll_obj->d_p_decoupl_lpf = spll_obj->y[1] + spll_obj->y[0];
spll_obj->y[0] = spll_obj->y[1];

Seven Han：

回复 user3784592:

看下这边wiki链接：

https://en.wikipedia.org/wiki/Low-pass_filter

程序中对应的离散方程

// Low pass filter //
//————————-//

spll_obj->y[1] = (spll_obj->d_p_decoupl*spll_obj->k1) – (spll_obj->y[0]*spll_obj->k2);
spll_obj->d_p_decoupl_lpf = spll_obj->y[1] + spll_obj->y[0];
spll_obj->y[0] = spll_obj->y[1];

user3784592：

回复 Seven Han:

应该是Z变换与差分方程间的相互转化