# An Application of Proportional-Resonant Controller in MMC-HVDC System under Unbalanced Voltage Conditions

• Accepted : 2014.04.07
• Published : 2014.09.01
• 56 14

#### Abstract

This paper presents an application of proportional-resonant (PR) current controllers in modular multilevel converter-high voltage direct current (MMC-HVDC) system under unbalanced voltage conditions. The ac currents are transformed and controlled in the stationary reference frame (${\alpha}{\beta}$-frame). Thus, the complex analysis of the positive and negative sequence components in the synchronous rotating reference frame (dq-frame) is not necessary. With this control method, the ac currents are kept balanced and the dc-link voltage is constant under the unbalanced voltage fault conditions. The simulation results based on a detailed PSCAD/EMTDC model confirm the effectiveness of the proposed control method.

#### Keywords

Integral-proportional controller;Modular multilevel converter-high voltage direct current system;Negative sequence component;Proportional-resonant controller;Unbalanced voltage conditions

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#### Cited by

1. Mitigation of voltage unbalance by using static load transfer switch in bipolar low voltage DC distribution system vol.90, 2017, https://doi.org/10.1016/j.ijepes.2017.02.009

#### Acknowledgement

Supported by : Korea Institute of Energy Technology Evaluation and Planning (KETEP)