dSPACE Based Adaptive Control Schemes for the Emergency Power Flow Controller in Microgrids

摘要

Distributed generation (DG) units with power electronics interfaced systems have been widely utilized in microgrids. These DG units can be considered as alternative real and reactive power sources besides satisfying the power demand of their local loads. In practice, DG units having higher power ratings are normally interfaced with utility grid via three-phase inverters equipped with dc storage units. Using proper controllers, both active and reactive power pumped into the utility grid from the DG units can be regulated as desired. In addition, with the reactive power control capability the DG units can also be used as reactive power compensation units for voltage regulation of microgrids. This paper presents a decoupled real and reactive power flow control scheme for an emergency power flow controller (EPFC) especially designed for some urgent microgrid operations. The proposed approach aims to achieve satisfactory adaptive and decoupled control features under grid-connected operating mode. The proposed control approach has been developed to control P or the voltage of the DC bus by adjusting the d-axis current of the inverter and to control Q by adjusting the component of q-axis current. To demonstrate the feasibility and verify the performance of the proposed control schemes, the related theoretical analysis and mathematical modeling are firstly described and followed by a set of comprehensive simulations and hardware studies on dSPACE1104. Both simulation and measured results have demonstrated a number of valuable merits, e.g. decoupled P and Q regulation capability, fast response in tracking P-Q commands and robust in a wide operating range.