A Self-synchronized Synchronverter Technology for Integrating PV Inverters to Grid without Using a Phase Locked Loop

  • Unique Paper ID: 142631
  • Volume: 2
  • Issue: 5
  • PageNo: 24-29
  • Abstract:
  • Photovoltaic systems are solar energy supply systems, which convert directly sunlight into electricity. A grid-connected inverter is typically used to interface the photovoltaic (PV) system into the utility grid. When significant portion of the grid power is inverter based, it will be advantageous to operate the inverter in the similar way as conventional power generators, or at least to imitate certain characteristics of the conventional generators. Synchronverter are grid connected inverter that mimics a synchronous generator. All conventional grid-connected inverters uses a phase locked loop (PLL) to provide the phase, frequency and amplitude of the grid voltage as references to the controller. But this PLL has got negative effects on the control performance. In this thesis the performance of the system is improved by removing the complex phase locked loop. It can automatically synchronize with the grid before connection and track the grid frequency after connection. This removes the slow element in the system that affects the speed of synchronization. Hence it considerably improves the control performance, reduces the complexity, cost and computational difficulty of the controller. Thus the controller is in principle, a power controller with integrated capability of frequency and voltage regulation together with self-synchronization control. Simulation results shows that the settling time as well as the peak overshoot of frequency tracking is improved considerably in the self-synchronization control.

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