Seven second order ladrc-pll structure design of active disturbance rejection controller

Compared with tradition PI control , Second order LADRC The technology is superior in dynamic performance and anti disturbance ability , Therefore, this paper proposes a method based on second-order active disturbance rejection technology LADRC-PLL structure , use LADRC
Modules replace tradition PLL Medium PI link , And make improvements on this basis , To improve its output stability in case of grid voltage drop .LADRC The structure includes a state observer 、 Disturbance compensation and linearity shape state By mistake Bad back Feed Law LSEF（linear state error feed⁃back）, Its basic structure is shown in the figure 2 Shown . among ,v by PLL Yes
Test input ;y Output... For the system , namely θ;u Control quantity for the system ;z1 、z2 、z3 They are the system output x1 、 Differential term of system output x2 And total disturbance x3 The estimate of ;b0 System gain .

In style ：ω0 、ωc The bandwidth of state observer and controller respectively ;ζ Is the damping ratio of the system . chart 3 For use LADRC Instead of PI After the link PLL structure , among ,uq by PLL Of q Axis component reference value ;
θ Is the reference value of the output angle ;y′ by q The actual value of the axis component ;Um Is the maximum value of network side voltage .
chart 4 For two kinds of PLL Dynamic performance comparison , When t = 0.2 s Added 1 Unit step disturbance . surface 1 For two kinds of PLL Performance parameter comparison , You can see LADRC-PLL Better dynamic performance