Current harmonic suppression strategy of grid connected inverter with PIR controller regulator

1、 Content abstract

A little
342- Can communicate 、 consulting 、 Answering question

2、 Content description

By using traditional adoption PI Vector control strategy [[]][[]] It is impossible to suppress the double frequency AC pulsation caused by imbalance in the system . So , This paper presents two new control strategies ： auxiliary PR Control and initiative PIR control .

4.3.1  PR Control analysis

PR controller [[][]] In the traditional PI Based on the controller , from R Link instead of I link []. about PR The open-loop transfer function of the controller is shown in the following formula (4-7) Shown ：

  (4-7)

The formula (4-7) in ： Is the proportional link gain , Is the resonant link gain , Is the resonant frequency of the resonant link , Because the resonant controller needs to suppress the AC component of frequency doubling , Therefore, the resonance is set as the 2 times , namely ：. According to the formula (4-7), Draw further PR Controller Bode chart [[]].

chart 4-5 PR Open loop Bode chart

From the above figure （4-5） analysis , about PR The amplitude gain of the controller near the angular frequency is much larger than that at other frequencies . That means , When the angular frequency of the deviation signal input by the controller is , use PR The negative feedback closed-loop system of the controller can track and suppress the AC signal .

4.3.2  PIR Control analysis

Is based on PI Based on the controller ,PIR Add one to the controller R link .PIR The open-loop transfer function of the controller is as follows (8) Shown ：

  (4-8)

The formula (4-8) in ： Is the proportional link gain , Is the integral link gain , Is the resonant link gain , Is the resonant frequency of the resonant link , Because the resonant controller is designed to suppress the AC component of double frequency , Therefore, the resonance is set as the power grid voltage frequency 2 times , namely ：.

According to the formula (4-8), obtain PIR Open loop under control Bode chart , As shown in the figure below . The following figure also shows PI Controller Bode chart  [18] For comparison .

chart 4-6 PIR and PI Open loop Bode chart

From the above figure 4-6 You know , At low frequencies ,PIR and PI The open loop gain is similar ,R The link doesn't work , That is, when the three-phase power grid voltage is balanced , In sync 2RC Inside , Only DC component exists ,PIR Can be like PI The controller is the same , Make the system output track the set value ; When the angular frequency of the input deviation signal is at the second harmonic ,PIR The resonant link plays a major role , It has large open-loop gain .

3、 Simulation analysis

p = 0.5; % p
Ti = 0.01; % i
Kr = 5000; % Resonant link gain
w0 = 100*2*pi; % Resonant point angular frequency
pi = tf([p*Ti 1],[Ti 0])
R_controller = tf([Kr 0],[1 0 w0^2])
sys_controller = series(pi,R_controller)

figure
bode(pi)
hold on
bode(sys_controller)

4、 Reference paper

be based on PIR Current harmonic suppression strategy of regulator grid connected inverter _ Liumengwei