Self-tuning virtual synchronous generator control for improving frequency stability in autonomous photovoltaic-diesel microgrids

Shi, Rongliang; Zhang, Xing; Hu, Chao; Xu, Huiling; Gu, Jianlei; Cao, Wei

doi:10.1007/s40565-017-0347-3

Cited by 69 publications

(28 citation statements)

References 23 publications

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“…From the (5), it could be established that, in exchange for adding the virtual inertia, the control system becomes more oscillatory and slower as the values of ξ1 and ωn1 become smaller. Due to space limitations, the design of the virtual inertia is not discussed here, and more details are available in [26]. From Figure 3, the transfer function in terms of the active powers as inputs can be obtained as follows:…”

Section: Impact Of Virtual Synchronous Generator (Vsg) On Frequency Smentioning

confidence: 99%

VSG-Based Dynamic Frequency Support Control for Autonomous PV–Diesel Microgrids

Zhang

2018

Energies

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This paper demonstrates the use of a novel virtual synchronous generator (VSG) to provide dynamic frequency support in an autonomous photovoltaic (PV)-diesel hybrid microgrid with an energy storage system (ESS). Due to the lack of enough rotating machines, PV fluctuation might give rise to unacceptable frequency excursions in the microgrid. The VSG entails controlling the voltage-source inverter (VSI) to emulate a virtual inertial and a virtual damping via power injection from/to the ESS. The effect of the VSG on the frequency is investigated. The virtual inertia decreases the maximum frequency deviation (MFD) and the rate of change of frequency (RoCoF), but in exchange for raising the virtual inertia, the system is more oscillating. Meanwhile, raising the virtual damping brings reductions in the amplitude of the oscillations of frequency. However, the dynamic frequency support provided by them is lagging behind. In this regard, an improved VSG based on the differential feedforward of the diesel generator set (DGS) output current is proposed to further mitigate the MFD and the RoCoF. Simulations and experimental results from an autonomous microgrid consisted of a 400 kW DGS, and a 100 kVA VSG are provided to validate the discussion.

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Section: Impact Of Virtual Synchronous Generator (Vsg) On Frequency Smentioning

confidence: 99%

VSG-Based Dynamic Frequency Support Control for Autonomous PV–Diesel Microgrids

Zhang

2018

Energies

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“…In [17], a VSG-based method with adaptive virtual inertia was proposed for PV generators in microgrid, which improved the frequency regulation ability of the grid. In [18], the effects of droop constant of primary frequency regulation and virtual inertia on the sub-synchronous and super synchronous oscillation modes were investigated in a microgrid system consisting of multiple PV-VSGs. On the oth- er hand, the existing research concentrates on the virtual inertia control methods applied in grid-connected IGs.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Different Virtual Inertia Control Methods for Inverter-based Generators

Sun

Liu

Shunan

et al. 2020

Journal of Modern Power Systems and Clean Energy

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With the rapid development of inverter-based generators (IGs), power grid is faced with critical frequency stability challenges because the existing IGs have no inertia. To equip IGs with inertial response, researchers have proposed several virtual inertia control methods, which can be classified into two categories: virtual synchronous generator (VSG) control and droop control based on rate of change of frequency (ROCOFdroop control). In this paper, the comparison between both virtual inertia control methods is conducted from three perspectives: mathematical model, output characteristic and small-signal stability. State-space models are firstly built to analyze the control mechanism of VSG control and ROCOF-droop control methods. Simulation and eigenvalue analysis are conducted to study the transient responses and oscillation characteristics of both methods, which is helpful to understand the advantages and limitations of existing virtual inertia control methods. Finally, the obtained theoretical results are validated through realtime laboratory (RT-LAB) hardware-in-loop simulation platform.

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“…DOI: 10.35833/MPCE.2018.000472 cy, and an improper frequency threshold may lead to the jittering of the virtual inertia value, resulting in VSG frequency and power fluctuations. In [14], [15], an optimal virtual inertia and virtual damping coefficients are calculated in real time according to power optimization algorithm of VSG, which reduces power overshoot. However, grid frequency monitoring and complicated calculation of optimization algorithm in real time are prerequisites, and the steady-state power control precision is not considered.…”

Section: Introductionmentioning

confidence: 99%

An Improved Virtual Inertia Algorithm of Virtual Synchronous Generator

Liu

et al. 2020

Journal of Modern Power Systems and Clean Energy

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Virtual synchronous generator (VSG) simulates the first-order motion equation of a synchronous generator (SG) with the algorithm. VSG can improve the system voltage and frequency support capabilities of a microgrid or a weak grid. It is now widely applied at a high penetration level of distributed generation (DG) systems. However, because there is a contradiction between active power steady-state deviation of VSG and dynamic impact regulation, the VSG running in grid-connected mode with existing strategies cannot meet the steady and dynamic control requirements. Thus, an improved virtual inertial control strategy of VSG is proposed in this paper. The active power impact is reduced effectively under the circumstance of damping coefficient D ω equal to 0 and a large inertia, thus the dynamic characteristic of active power is improved and its steady-state characteristic is maintained. Firstly, based on the analysis of the damping coefficient effect on the system dynamic process, two forms of improved virtual inertia algorithms are put forward by cascading a differential link into different positions of the first-order virtual inertia forward channel. Then, by comparing the characteristics of the system with the two improved algorithms, the improved virtual inertial strategy based on differential compensation is proven to be better, and the design of its parameters is analyzed. Finally, simulation and experimental results verify the effectiveness of the proposed algorithm.

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Self-tuning virtual synchronous generator control for improving frequency stability in autonomous photovoltaic-diesel microgrids

Cited by 69 publications

References 23 publications

VSG-Based Dynamic Frequency Support Control for Autonomous PV–Diesel Microgrids

VSG-Based Dynamic Frequency Support Control for Autonomous PV–Diesel Microgrids

Comparison of Different Virtual Inertia Control Methods for Inverter-based Generators

An Improved Virtual Inertia Algorithm of Virtual Synchronous Generator

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