In this program, if the production are soaked, the difference between the operator production as well as the actual returns is actually provided to the input of one’s integrator with a gain of K a to allow the fresh new collected worth of the latest integrator shall be left at a real worthy of. New get of an enthusiastic anti-windup operator is oftentimes chose due to the fact K a great = step one / K p to stop the figure of your minimal current.
Fig. mejores sitios de citas sin gluten dos.37 suggests the latest occurrence out-of integrator windup to have good PI newest operator, that is made by a big improvement in the source value. Fig. dos.37A shows new overall performance regarding a current control instead of an anti-windup handle. Due to the over loaded output voltage, the genuine current exhibits a giant overshoot and you will a lengthy mode time. At exactly the same time, Fig. 2.37B reveals a recently available control which have a keen anti-windup control. If output was over loaded, the fresh new gathered worth of the newest integrator is kept at an excellent proper worth, resulting in a significantly better performance.
2.six.2.step one Increases alternatives procedure of the brand new proportional–integral most recent controller
Discover the handle data transfer ? c c of your latest control to be in this 1/10–1/20 of your own switching regularity f s w and you will less than step 1/25 of one’s testing frequency.
New actions step 1 and 2 try similar along, we.age., the switching volume would be determined by the mandatory data transfer ? c c to have current control.
a dozen.dos.dos Secure area for unmarried-loop DC-link current control
According to the Nyquist stability criterion, a system can be stabilized by tuning the proportional gain under the condition, i.e., the magnitude is not above 0 dB at the frequency where the phase of the open-loop gain is (-1-2k)? (k = 0, 1, 2.?) [ 19 ]. Four sets of LC-filter parameter values from Table 12.1 , as listed in Table 12.2 , are thus used to investigate the stability of the single-loop DC-link current control. Fig. 12.4 shows the Bode plots of the open-loop gain of the single-loop DC-link current control Go, which can be expressed as
Figure 12.4 . Bode plots of the open-loop gain Go of the single-loop DC-link current control (kpdc = 0.01) corresponding to Table II. (A) Overall view. (B) Zoom-in view, 1000–1900 Hz. (C) Zoom-in view, 2000–3500 Hz.
where Gdel is the time delay, i.e., G d e l = e ? 1.5 T s and Gc is the DC-link current PI controller, i.e., Gc = kpdc + kidc/s. The proportional gain kpdc of the PI controller is set to 0.01 and the integrator is ignored since it will not affect the frequency responses around ?c1 and ?c2. It can be seen that the CSC system is stable in Cases II, III, and IV. However, it turns out to be unstable in Case I, because the phase crosses ?540 and ?900 degrees at ?c1 and ?c2, respectively.
To further verify the relationship between the LC-filter parameters and the stability, root loci in the z-domain with varying kpdc under the four sets of the LC-filter parameters are shown in Fig. 12.5 . It can be seen that the stable region of kpdc becomes narrow from Case IV to Case II. When using the LC-filter parameters as Cases I, i.e., L = 0.5 mH and C = 5 ?F, the root locus is always outside the unity circle, which indicates that the system is always unstable. Thus, the single-loop DC-link current control can be stabilized with low resonance frequency LC filter, while showing instability by using high resonance frequency LC filter. The in-depth reason is that the phase lag coming from the time delay effect becomes larger at the resonances from low frequencies to high frequencies, which affect the stability of the single-loop DC-link current control.