摘要：In this paper, a fast self-synchronization known as virtual synchronous converter (VSCon)
between single-phase microgrid and inverter in low-voltage microgrid, has been developed in
Matlab/Simulink. The idea is to any phase locked loop (PLL) circuit for inverter-microgrid
synchronization in order to improve the synchronization time. As known, it is difficult and
lengthy process to tune the PLL gain parameters to reach suitable performance for
synchronizing among the voltage, phase-angle and frequency between them. Due to this problem,
a fast self synchronization technique is needed in order to minimize the time losses at the
microgrid connection. Therefore, the VSCon has been developed which is based on the
synchronous generator mathematical model but in virtual environment representation. It has
been applied in the inverter control for generating switching pattern to the inverter switches in
order to respond to the grid voltage for improve the synchronization. For a prove of concept,
several simulation tests in MATLAB models have been conducted, in order to see the
effectiveness of this VSCon. First test has been conducted, when a 240V, 50Hz frequency grid
source is used for observing the self-synchronization the system with the power flows output.
Furthermore, the next test is conducted when the grid frequency is changed from the rated
frequency at 50Hz to 51Hz and the result shows the VSCon in inverter control takes nearly
40ms to synchronize to this new frequency value. The test on grid phase-angle delay also been
tested when ac grid voltage has 150
phase delay. As from all the results, the improved inverter
control with VSCon structure is able to have fast and self-synchronized between the invertergrid
connection before the power from the inverter can be transferred.
