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A Decoupled Droop Control Strategy for Cascaded Multicell Inverter with Low-Frequency Modulation

Conference · · 2022 IEEE Energy Conversion Congress and Exposition (ECCE)
 [1];  [1];  [1]
  1. University of Nebraska-Lincoln,Department of Electrical and Computer Engineering,Lincoln,NE,USA,68588-0511

Cascaded multicell inverter (CMI), featured by its merits of modularity and fault-tolerance, is suitable for medium-voltage applications without using bulky step-up transformers. However, little research has reported grid-forming control of the CMI for the application in the power grid with high penetrations of inverter-interfaced generation. To bridge this research gap, this paper proposes a novel droop control strategy for the CMI with a low-frequency modulation to offer inertia and reactive power support to the power grid. A decoupled Q/V droop control strategy is proposed to eliminate the coupling effect from the P/ω control loop caused by the phase-angle difference between the voltages of the CMI and the grid. The output of the Q/V control loop is set as the reference voltage for each cell of the CMI, which makes the CMI naturally a voltage source to provide a grid-forming capability. Finally, the proposed control strategy shows great active and reactive power regulation and sharing capability, which is validated by simulation on two 100 kW, 2.4 kV CMIs connected in parallel to a power grid.

Research Organization:
Board of Regents, University of Nebraska, University of Nebraska-Lincoln
Sponsoring Organization:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office
DOE Contract Number:
EE0009831
OSTI ID:
1922586
Report Number(s):
DOE-UNL-0009831-1
Journal Information:
2022 IEEE Energy Conversion Congress and Exposition (ECCE), Conference: IEEE Energy Conversion Congress and Exposition 2022 (ECCE 2022), Detroit, MI, USA, Oct. 8-13, 2022
Country of Publication:
United States
Language:
English

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