Inside scheme, if production are over loaded, the essential difference between the fresh operator yields while the actual efficiency is provided returning to the enter in of your integrator having an increase out of K a to allow this new amassed value of the newest integrator can be remaining on a real worth. The brand new obtain of an anti-windup controller is sometimes selected just like the K a good = 1 / K p to stop the brand new personality of one’s restricted current.

Fig. dos.37 suggests new sensation out of integrator windup getting an effective PI newest controller, that’s created by a big improvement in the new source worthy of. Fig. dos.37A shows the fresh new performance off a recently available control instead of an anti-windup manage. Simply because of its saturated productivity current, the true newest showcases a big overshoot and you will an extended function big date. At exactly the same time, Fig. dos.37B shows a recently available operator that have an anti-windup handle. In the event the returns is saturated, new collected property value the fresh integrator is going to be left at good proper worthy of, leading to a significantly better results.

dos.6.dos.step one Growth alternatives procedure for this new proportional–integral newest controller

Discover the handle bandwidth ? c c of the most recent operator to get contained in this 1/10–1/20 of changing volume f s w aplicaciones de citas para adultos mamita de azucar and you may less than step 1/twenty five of your own testing frequency.

The new steps step one and you can dos was compatible with each other, i.elizabeth., the switching frequency are going to be determined by the desired bandwidth ? c c to have current control.

12.dos.2 Stable area for solitary-circle DC-connect 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 G_o, which can be expressed as

Figure 12.4 . Bode plots of the open-loop gain G_o of the single-loop DC-link current control (k_pdc = 0.01) corresponding to Table II. (A) Overall view. (B) Zoom-in view, 1000–1900 Hz. (C) Zoom-in view, 2000–3500 Hz.

where G_del is the time delay, i.e., G d e l = e ? 1.5 T s and G_c is the DC-link current PI controller, i.e., G_c = k_pdc + k_idc/s. The proportional gain k_pdc 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 k_pdc under the four sets of the LC-filter parameters are shown in Fig. 12.5 . It can be seen that the stable region of k_pdc 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.