Model Reduction for Inverters With Current Limiting and Dispatchable Virtual Oscillator Control

Ajala, Olaoluwapo; Lu, Ming–Feng; Dhople, Sairaj V.; Johnson, Brian; Domínguez-García, Alejandro D.

doi:10.1109/tec.2021.3083488

Cited by 32 publications

(15 citation statements)

References 40 publications

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“…The reason is that in droop‐based method, over‐current protection may be achieved by directly limiting the reference to the inner current control loop which eventually may lead to loss of synchronization and instability [109]. Furthermore, in the recent investigation on dVOC, [110] investigated adding reference‐current limiting to a reduced‐model of dVOC which decreases the computational burden as well as increases the reliability of the system.…”

Section: Limitation Of Virtual Oscillator‐based Controllermentioning

confidence: 99%

Virtual oscillator‐based methods for grid‐forming inverter control: A review

Aghdam

Agamy

2022

IET Renewable Power Gen

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In inverter‐dominant power systems, grid‐forming (GFM) inverters regulate voltage and frequency. To construct GFM inverters, conventionally, various control methods based on synchronous machine emulation or droop characteristics have been employed. However, recently, inverters are regulated by Virtual Oscillator Control (VOC) to emulate the dynamics of a weakly nonlinear oscillators. In contrast to droop control, VOC is a time‐domain controller that enables interconnected inverters to stabilize arbitrary initial conditions to a synchronized sinusoidal limit cycle rapidly. The fast synchronization, accurate power sharing in grid‐connected and islanded modes, simple and robust implementation make it a promising candidate for inverter‐dominant power systems. Moreover, VOC removes the computational burden within machine emulation‐based methods and provides an approach to measure the frequency without employing phase‐locked loop (PLL). Hence, to leverage the advantages of this method and expand its application in power system control, this paper reviews different VOC implementations. Mainly, this paper focuses on the studies related to the fundamental theory of oscillators and design process. Additionally, there are discussions on the stability analysis of VOC‐based systems, harmonics and pre‐synchronization. Challenges on the compatibility with heterogeneous controllers, fault ride‐through and other limitations of VOC including non‐inertial response and coupled power control are investigated and solutions are outlined.

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Section: Limitation Of Virtual Oscillator‐based Controllermentioning

confidence: 99%

Virtual oscillator‐based methods for grid‐forming inverter control: A review

Aghdam

Agamy

2022

IET Renewable Power Gen

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“…1. (b) a dispatchable VOC (d-VOC) is used with nested voltage and current control loops [21], [22]. The d-VOC provides continuous reference voltage and phase angle information.…”

Section: Introductionmentioning

confidence: 99%

“…At the same time, the control over the healthy phases should be affected as minimum as possible [35], [36]. The existing VOC based gridforming controller as presented in [21], [22] cannot provide satisfactory performance under unbalanced fault. A simulation study is presented in Section III where an existing VOC based grid-forming controller is used to ride through an unbalanced fault condition.…”

Section: Introductionmentioning

confidence: 99%

A New Virtual Oscillator-Based Grid-Forming Controller with Decoupled Control Over Individual Phases and Improved Performance of Unbalanced Fault Ride-Through

Ghosh

Tummuru

Rajpurohit

2023

IEEE Trans. Ind. Electron.

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Virtual Oscillator (VO) control is the latest and promising control technique for grid-forming and grid-supporting inverters. VO Controllers (VOCs) provide time-domain synchronization with a connected electrical network. At the same time, a VOC can incorporate additional nested control loops for meets the system-level requirements such as fault ride-through capability. However, existing VOCs have two limitations. Firstly, the existing VOC does not have decoupled control over individual phases. As a result, the performance of the existing VOC is not satisfactory in presence of unbalanced grid voltages. Secondly, the fault ride-through performance of the existing VOC under an unbalanced fault is not satisfactory. The power delivery at a healthy phase gets affected by the faulty phase. This paper has introduced a modified VO based system-level controller to overcome the limitations mentioned above. Systematic development of the proposed control architecture with analytical reasoning is presented. Simulation studies and hardware experiments are conducted for validation.

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“…A grid-forming controller should meet the system-level requirements such as fault ride-through capability, MPPT capability, and capability to perform under unbalanced grid conditions [8]. The recent research works [9]- [11] have provided a very general VO-based control architecture where all the above-mentioned system-level functionalities are included.…”

Section: Introductionmentioning

confidence: 99%

“…However, the new grid codes prevent grid-forming converters from being disconnected easily from the network in such a condition as mentioned above [13]. The second option is to enter into current control mode by activating the fault ride-through controller [9], [14]. However, the effective synchronization of a grid-forming controller with the connected network gets severely affected in the current control mode [8].…”

Section: Introductionmentioning

confidence: 99%