Page 10 - Modern Control of DC-Based Power Systems

List of Figures ix

Figure 2.40 Nyquist plot of the minor loop gain for the cascade of 64
PICM_FB-controlled buck converter and PICM_FB-
controlled VSI (unstable case)
Figure 2.41 Bus voltage and VSI three-phase output voltage transient in 64
correspondence of a symmetric VSI load step from 20Ω
to 10Ω for the cascade of PICM_FB-controlled buck
converter and PICM_FB-controlled VSI (unstable case)
Figure 2.42 Nyquist plot of the minor loop gain for the cascade of 65
VM_FB-controlled buck converter and PICM_FB-
controlled VSI (unstable case)
Figure 2.43 Bus voltage and VSI three-phase output voltage transient in 65
correspondence of a symmetric VSI load step from 20Ω to
10Ω for the cascade of VM_FB-controlled buck converter
and PICM_FB-controlled VSI (unstable case)
Figure 2.44 A dynamic system under test to find the input-to-output 66
transfer function G uy sðÞ:
Figure 2.45 A wideband PRBS signal (red (light gray in print version)) 67
and a narrowband sinusoidal signal (blue (dark gray in print
version)) in the time domain (top) and in the frequency
domain (bottom)
Figure 2.46 Conceptual cascade of converters showing the injection of 68
PRBS over the load converter control and embedded
control platform for online identification of source
impedance
Figure 2.47 Implementation of the routines of the WSI technique in an 70
embedded controller
Figure 2.48 Block diagram of LFSR for PRBS generation 71
Figure 2.49 Identification of the output impedance of the source 74
converter with two techniques: the digital network
analyzer and the Wideband System Identification technique
(WSI)
Figure 2.50 Voltage and current measurements at the impedance 75
measurement point with the Digital Network Analyzer
technique
Figure 2.51 Bode plot of the identified output impedance of the source 76
converter compared to the analytic transfer function with
the Digital Network Analyzer technique
Figure 2.52 Voltage and current measurements at the impedance 76
measurement point with the Wideband System
Identification technique
Figure 2.53 Bode plot of the identified output impedance of the source 77
converter compared to the analytic transfer function with
the Wideband System Identification technique
Figure 3.1 Bode plot of the system under study 87