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Double Synchronous Unified Virtual Oscillator Control for Asymmetrical Fault Ride-Through in Grid-Forming Voltage Source Converters
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  • M A Awal ,
  • Md Rifat Kaisar Rachi ,
  • Hui Yu ,
  • Iqbal Husain ,
  • Srdjan Lukic
M A Awal
North Carolina State University, North Carolina State University

Corresponding Author:[email protected]

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Md Rifat Kaisar Rachi
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Iqbal Husain
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Srdjan Lukic
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A double synchronous unified virtual oscillator controller (dsUVOC) is proposed for grid-forming voltage source converters to achieve synchronization to the fundamental frequency positive- and negative-sequence components of unbalanced or distorted grids. The proposed controller leverages a positive- and a negative-sequence virtual oscillator, a double-sequence current reference generator, and a double-sequence vector limiter. Under fault conditions, the controller enables to clamp the converter output current below the maximum value limited by the converter hardware while retaining synchronization without a phase-locked-loop (PLL) regardless of the balanced or unbalanced nature of grid faults. Consequently, balanced and unbalanced fault ride-through can be achieved without the need for switching to a back-up controller. The paper presents the systematic development of the double-synchronous structure along with detail design and implementation guidelines. Validation of the proposed controller is provided through extensive control-hardware-in-the-loop (CHIL) experiments.
Jun 2023Published in IEEE Transactions on Power Electronics volume 38 issue 6 on pages 6759-6763. 10.1109/TPEL.2022.3227729