Next-generation power networks will contain large numbers of grid-connected inverters satisfying a significant fraction of system load. Since each inverter model has a relatively large number of dynamic states, it is impractical to analyze complex system models where the full dynamics of each inverter are retained. To address this challenge, we derive a reduced-order structure-preserving model for parallel-connected grid-Tied three-phase inverters. Here, each inverter in the system is assumed to have a full-bridge topology, LCL filter at the point of common coupling, and the control architecture for each inverter includes a current controller, a power controller, and a phase-locked loop for grid synchronization. We outline a structure-preserving reduced-order inverter model with lumped parameters for the setting where the parallel inverters are each designed such that the filter components and controller gains scale linearly with the power rating. By structure preserving, we mean that the reduced-order three-phase inverter model is also composed of an LCL filter, a power controller, current controller, and PLL. We show that the system of parallel inverters can be modeled exactly as one aggregated inverter unit and this equivalent model has the same number of dynamical states as any individual inverter in the system. Numerical simulations validate the reduced-order model.
|Original language||English (US)|
|Title of host publication||2017 IEEE 18th Workshop on Control and Modeling for Power Electronics, COMPEL 2017|
|Publisher||Institute of Electrical and Electronics Engineers Inc.|
|State||Published - Aug 18 2017|
|Event||18th IEEE Workshop on Control and Modeling for Power Electronics, COMPEL 2017 - Stanford, United States|
Duration: Jul 9 2017 → Jul 12 2017
|Name||2017 IEEE 18th Workshop on Control and Modeling for Power Electronics, COMPEL 2017|
|Other||18th IEEE Workshop on Control and Modeling for Power Electronics, COMPEL 2017|
|Period||7/9/17 → 7/12/17|
Bibliographical noteFunding Information:
This work was supported by the U.S. Department of Energy (DOE) Solar Energy Technologies Office under Contract No. DE-EE0000-1583.
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