Improved comprehensive energy-based control for MMC-HVDC system

Shi, Xianqiang; Yang, Renxin; Cai, Xu; Fang, Zixi; Dong, Peng; Rao, Fangquan

doi:10.1016/j.ijepes.2022.108593

Cited by 6 publications

(4 citation statements)

References 28 publications

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“…A VSC-based HVDC system provides independent control of active and reactive power and allows for bidirectional power flow (Soomro et al, 2021). Among VSCs, researchers have devoted significant attention to the Modular Multilevel Converter (MMC), as shown in Figure 1, due to its advantages, such as modularity, scalability, increased efficiency, decreased total harmonic distortion (THD), and fault-blocking capacity (Ali et al, 2020;Jia et al, 2023;Shi et al, 2023). The leading manufacturers of MMC technology include Siemens, EPRI, ALSTOM, and ABB, representing the latest generation of VSCs.…”

Section: Introductionmentioning

confidence: 99%

Innovative model predictive control for HVDC: circulating current mitigation and fault resilience in Modular Multilevel converters

Bhutto,

Soomro,

Ali

et al. 2024

Front. Energy Res.

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This study presents an advanced Model Predictive Control (MPC) technique designed to mitigate Circulating Current (CC) in HVDC systems equipped with Modular Multilevel Converters (MMC). This MPC strategy eliminates the need for traditional PI regulators and pulse width modulation, improving system dynamics and control accuracy. It excels in managing output currents and mitigating voltage fluctuations in sub-module capacitors. Moreover, the paper introduces a novel communication-free Fault Ride-Through (FRT) method that makes a DC chopper redundant, enabling rapid recovery from disturbances. To reduce the computational burden of standard MPC algorithms, an aggregated MMC model is proposed, significantly decreasing the computational complexity. Simulation studies validate the new MPC algorithm’s capability in regulating AC side current, reducing CC, and ensuring capacitor voltage stability under varying conditions. The findings indicate that the proposed MPC controller outperforms traditional PI and PR-based methods, offering enhanced dynamic response, decreased steady-state error, and lowered converter losses, which contribute to smoother DC link voltages. Future research will focus on system scalability, renewable energy integration, and empirical validation through hardware-in-the-loop testing.

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Section: Introductionmentioning

confidence: 99%

Innovative model predictive control for HVDC: circulating current mitigation and fault resilience in Modular Multilevel converters

Bhutto,

Soomro,

Ali

et al. 2024

Front. Energy Res.

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“…The suggested approach computes the active power current component in real‐time to offset MMC losses during a fault, rather than nullifying it 25 . The proposed method is simple and less complex than the control strategy used in the literature 26,27 The paper is structured as follows.…”

Section: Introductionmentioning

confidence: 99%

“…25 The proposed method is simple and less complex than the control strategy used in the literature. 26,27 The paper is structured as follows. Section 2 depicts the CC cell-MMC topology and operating principle of MMC.…”

mentioning

confidence: 99%

A cross connected cell based modular multilevel converter for HVDC system with DC short‐circuit fault ride‐through capability

Kumar,

Sreenivasarao

2024

Circuit Theory & Apps

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SummaryThe non‐permanent dc short‐circuit fault is a crucial issue in overhead high voltage dc transmission (HVDC) lines. In this paper, a cross connected (CC) cell also known as hexagonal switch cell (HSC) based modular multilevel converter (MMC) with dc short‐circuit fault ride through feature is addressed for an HVDC system. During normal operation, the CC cell‐MMC is capable of producing an identical number of levels while using fewer power devices than full‐bridge (FB) and clamp double sub‐module (CDSM)‐based MMCs. Similarly to the FB‐MMC and CDSM‐MMC, the provided CC cell‐MMC not only blocks the dc fault current but can also function as a static synchronous compensator (STATCOM) during a DC‐Bus fault. The Proposed control technique uses MMC as a STATCOM to inject reactive power during a pole‐to‐pole DC‐Bus fault to keep the grid stable. The control approach comprises injecting zero‐sequence voltage into each phase to balance the mean voltage of capacitors and arm currents. The fundamental zero‐sequence voltage is obtained by a simple stationary reference frame‐based controller. The control strategy's efficacy is evaluated in MATLAB and confirmed in the Opal‐RT environment.

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“…Different control strategies for MMC-HVDC systems have been extensively proposed in the literature. In [13], the authors develop an energy-based control of the MMC-HVDC system to interconnect two non-synchronous AC grids. The proposed strategy achieves full control of the converter's inner dynamics, regardless of the dc line length.…”

Section: Introductionmentioning

confidence: 99%

Control of an Offshore Wind Farm Considering Grid-Connected and Stand-Alone Operation of a High-Voltage Direct Current Transmission System Based on Multilevel Modular Converters

Paulo

Almeida

et al. 2023

Energies

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This work presents a control strategy for integrating an offshore wind farm into the onshore electrical grid using a high-voltage dc transmission system based on modular multilevel converters. The proposed algorithm allows the high-voltage DC system to operate in grid-connected or stand-alone modes, with the second case supplying power to local loads. In either mode, the modular multilevel rectifier works as a grid-forming converter, providing the reference voltage to the collector network. During grid-connected operation, the modular multilevel inverter regulates the DC link voltage while the generating units are controlled to maximize power extracted from the wind turbines. Conversely, in the event of grid disconnection, the onshore modular multilevel converter takes over the regulation of the AC voltage at the point of connection to the grid, ensuring energy supply to local loads. Simultaneously, the generator controller transitions from tracking the maximum power of the wind turbines to regulating the DC link voltage, preventing excessive power injection into the transmission DC link. Additionally, the turbine pitch angle control regulates the speed of the generator. Mathematical models in the synchronous reference frame were developed for each operation mode and used to design the converter’s controllers. A digital model of the wind power plant and a high-voltage dc transmission system was implemented and simulated in the PSCAD/EMTDC program. The system modeled includes two groups of wind turbines, generators, and back-to-back converters, in addition to a DC link with a rectifier and an inverter station, both based on modular multilevel converters with 18 submodules per arm, and a 320 kV/50 km DC cable. Aggregate models were used to represent the two groups of wind turbines, where 30 and 15 smaller units operate in parallel, respectively. The performance of the proposed control strategy and the designed controllers was tested under three distinct scenarios: disconnection of the onshore converter from the AC grid, partial loss of a wind generator set, and reconnection of the onshore converter to the AC grid.

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Improved comprehensive energy-based control for MMC-HVDC system

Cited by 6 publications

References 28 publications

Innovative model predictive control for HVDC: circulating current mitigation and fault resilience in Modular Multilevel converters

Innovative model predictive control for HVDC: circulating current mitigation and fault resilience in Modular Multilevel converters

A cross connected cell based modular multilevel converter for HVDC system with DC short‐circuit fault ride‐through capability

Control of an Offshore Wind Farm Considering Grid-Connected and Stand-Alone Operation of a High-Voltage Direct Current Transmission System Based on Multilevel Modular Converters

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