Figure 16.10 Experimental results for the case with a linear load when inverters have the same per‐unit impedance: with the robust droop controller (left column) and with the conventional droop controller (right column).
Figure 16.11 Experimental results for the case with the same per‐unit impedance using the robust droop controller: with Ke = 10 (left column) and Ke = 1 (right column).
Figure 16.12 Experimental results with a nonlinear load: with the robust droop controller (left column) and with the conventional droop controller (right column).
Figure 16.13 Robust droop controller for C‐inverters.
Figure 16.14 Experimental results of C‐inverters (left column) and R‐inverters (right column) with a linear load RL = 9 Ω.
Figure 16.15 Experimental results of C‐inverters (left column) and R‐inverters (right column) with a nonlinear load.
Figure 16.16 Robust droop controller for L‐inverters.
Figure 16.17 Experimental results of L‐inverters with a linear load: with the robust droop controller (left column) and the conventional droop controller (right column).
Figure 16.18 Experimental results of L‐inverters with a nonlinear load: with the robust droop controller (left column) and with the conventional droop controller (right column).
Figure 17.1 The model of a single‐phase inverter.
Figure 17.2 The closed‐loop system consisting of the power flow model of an inverter and a droop controller.
Figure 17.3 Interpretation of transformation matrices TL and TC.
Figure 17.4 Interpretation of the universal transformation matrix T.
Figure 17.5 Universal droop controller.
Figure 17.6 Real‐time simulation results of three inverters with different types of output impedance operated in parallel.
Figure 17.7 Experimental set‐up consisting of an L‐inverter, an R‐inverter, and a C‐inverter.
Figure 17.8 Experimental results with the universal droop controller.
Figure 18.1 The self‐synchronized universal droop controller.
Figure 18.2 Experimental results of self‐synchronization with the R‐inverter.
Figure 18.3 Experimental results when connecting the R‐inverter to the grid.
Figure 18.4 Experimental results with the R‐inverter: performance during the whole experimental process.
Figure 18.5 Experimental results with the R‐inverter: regulation of system frequency and voltage in the droop mode.
Figure 18.6 Experimental results with the R‐inverter: change in the DC‐bus voltage VDC.
Figure 18.7 Experimental results of self‐synchronization with the L‐inverter.
Figure 18.8 Experimental results with the L‐inverter: connection to the grid.
Figure 18.9 Experimental results with the L‐inverter: performance during the whole experimental process.
Figure 18.10 Experimental results with the L‐inverter: regulation of system frequency and voltage in the droop mode.
Figure 18.11 Experimental results with the L‐inverter: change in the DC‐bus voltage VDC.
Figure 18.12 Experimental results of self‐synchronization with the L‐inverter with the robust droop controller.
Figure 18.13 Experimental results from the L‐inverter with the robust droop controller: connection to the grid.
Figure 18.14 Experimental results from the L‐inverter with the robust droop controller: performance during the whole experimental process.
Figure 18.15 Experimental results from the L‐inverter with the robust droop controller: regulation of system frequency and voltage in the droop mode.
Figure 18.16 Experimental results with the L‐inverter under robust droop control: change in the DC‐bus voltage VDC.
Figure 18.17 A microgrid including three inverters connected to a weak grid.
Figure 18.18 Real‐time simulation results from the microgrid.
Figure 19.1 A general three‐port converter with an AC port, a DC port, and a storage port.
Figure 19.2 DC‐bus voltage controller to generate the real power reference.
Figure 19.3 The universal droop controller when the positive direction of the current is taken as flowing into the converter.
Figure 19.4 Finite state machine of the droop‐controlled rectifier.
Figure 19.5 Illustration of the operation of the droop‐controlled rectifier.
Figure 19.6 The θ‐converter.
Figure 19.7 Control structure for the droop‐controlled rectifier.
Figure 19.8 Experimental results in the GS mode.
Figure 19.9 Experimental results in the NS‐H mode.
Figure 19.10 Experimental results in the NS‐L mode.
Figure 19.11 Transient response when the system starts up.
Figure 19.12 Transient response when a load is connected to the system.
Figure 19.13 Experimental results showing the capacity potential of the rectifier: real power P, grid voltage Vg, DC‐bus voltage vDC, and Δϕ.
Figure 19.14 Controller for the conversion leg.
Figure 19.15 Comparative experimental results with a conventional controller.
Figure 20.1 A grid‐connected single‐phase inverter with an LCL filter.
Figure 20.2 The equivalent circuit diagram of the controller.
Figure 20.3 The overall control system.
Figure 20.4 Controller states.
Figure 20.5 Implementation diagram of the current‐limiting universal droop controller.
Figure 20.6 Operation with a normal grid.
Figure 20.7 Transient response of the controller states with a normal grid.
Figure 20.8 Operation under a grid voltage sag 110 V → 90 V → 110 V for 9 s.
Figure 20.9 Controller states under the grid voltage sag 110 V → 90 V → 110 V for 9 s.
Figure 20.10 Operation under a grid voltage sag 110 V → 55 V → 110 V for 9 s.
Figure 20.11 Controller states under the grid voltage sag 110 V → 55 V → 110 V for 9 s.
Figure