As previously highlighted, a good dynamic behavior is required in order to take into account the loading effect of the power converter supplied by the PV emulator.
The possibility to impose the closed-loop poles, by using the pole placement technique, described in Sect. 8.4, permits to obtain a fast dynamical response.
The output impedance of the DC/DC converter gives information on the range of frequencies in which the PV emulator behaves like an ideal voltage source.
As previously said, a low impedance value is desirable in order to correctly reproduce the current demand coming from the loading converter.
The closed-loop poles are chosen as a pair of complex and conjugate and a real one. The corresponding kt coefficients are chosen equal to k12 = 2я(500 ± j500) and k3 = 2я500. This choice assures a dynamical response with a rise time in the order of milliseconds.
The equivalent output capacitance corresponds to about 10 iF that is smaller than a typical expected load capacitance.
Fig. 8.18 Implemented model of the PV emulator
The obtained output impedance versus frequency curve, calculated by Eqs. (8.34) and (8.35), is shown in Fig. 8.17. It is possible to observe that it exhibits a maximum equal to 2.25 X at 1.6 kHz (104 rad/s).