Selecting frequency and parameters of DC-fault tolerant Non-Isolated high power MMC DC/DC Converter

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Case Study of Non-Isolated MMC DC-DC Converter in HVDC Grids

Peer reviewedPublisher PD

Phasor Analytical Model of Non-isolated DC/DC Converter Based on Modular Multilevel Converter for DC Transmission Grids

Non-isolated DC/DC converter based on modular multilevel converter (MMC) technology is expected to play an important role in future DC transmission grids. This paper presents a phasor analytical model for this new family of converters which is suitable for a range of studies like DC grid power flow or DC/DC parametric design. The 30th-order phasor model is derived in 3 coordinate frames: zero sequence (DC), fundamental frequency (($\pmb{dq}$)), and double frequency ($d2q2$). The second-harmonic current suppression control is included as an option. Additionally, an estimation of the required control signals is presented, and a closed-loop model is developed which facilitates direct calculation of all variables and fast parametric studies. The accuracy of the proposed models is verified against a detailed PSCAD model for a wide range of parameters. The studies illustrate the importance of the second-harmonic components on the model accuracy. Finally, the impact of the converter parameters on the performance is studied, and a basic eigen-value stability analysis is given

Control methods for fault current limiting using hybrid HV DC Circuit Breakers

This work was supported by the European Union’s Horizon 2020 research and innovation program under grant No. 691714.Peer reviewedPublisher PD