Robust PI control of a grid-connected voltage source inverter for virtual inertia response in weak grid conditions

In this paper, the virtual synchronous generator (VSG) concept is utilized in the controller of the grid-connected dual two-level voltage source inverter (DTL VSI). First, the topology of the VSG and the DTL VSI are presented. Then, the state-space equations of the DTL VSI and the grid-connected two-level voltage source inverter (TL VSI), regarding the presence of the phase-locked loop (PLL) and the VSG, are given. Next, the small-signal modeling of the DTL VSI and the TL VSI is realized. Eventually, the stability enhancement in the DTL VSI compared with the TL VSI is demonstrated. In the TL VSI, large values of virtual inertia could result in oscillations in the power system. However, the ability of the DTL VSI in damping oscillations is deduced. Furthermore, in the presence of nonlinear loads, the potentiality of the DTL VSI in reducing grid current Total Harmonic Distortion (THD) is evaluated. Finally, by using a proper reference current command signal, the abilities of the DTL VSI and the TL VSI in supplying nonlinear loads and providing virtual inertia are assessed simultaneously. The simulation results prove the advantages of the DTL VSI compared with the TL VSI in virtual inertia emulation and oscillation damping, which are realized by small-signal analysis.

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An Improved Virtual Inertia Control for Three-Phase Voltage Source Converters Connected to a Weak Grid

IEEE Transactions on Power Electronics ◽

10.1109/tpel.2018.2885513 ◽

2019 ◽

Vol 34 (9) ◽

pp. 8660-8670 ◽

Cited By ~ 22

Author(s):

Jingyang Fang ◽

Pengfeng Lin ◽

Hongchang Li ◽

Yongheng Yang ◽

Yi Tang

Keyword(s):

Voltage Source ◽

Voltage Source Converters ◽

Phase Voltage ◽

Weak Grid ◽

Three Phase ◽

Virtual Inertia ◽

Inertia Control

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Power Grid Voltage Modified Direct Power Control (DPC) for a Weak Grid Connected to Voltage Source Inverter (VSI) and Stability Analysis

International Journal for Research in Applied Science and Engineering Technology ◽

10.22214/ijraset.2020.31080 ◽

2020 ◽

Vol 8 (8) ◽

pp. 989-997

Author(s):

Ishteyaque Zafar

Keyword(s):

Stability Analysis ◽

Power Control ◽

Power Grid ◽

Voltage Source ◽

Voltage Source Inverter ◽

Direct Power ◽

Direct Power Control ◽

Grid Voltage ◽

Weak Grid

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A Control Approach and Design Consideration of PV/Diesel Hybrid Distributed Generation System Using Dual Voltage Source Inverter for Weak Grid

2006 SICE-ICASE International Joint Conference ◽

10.1109/sice.2006.315483 ◽

2006 ◽

Cited By ~ 2

Author(s):

H. Dehbonei ◽

S.r. Lee ◽

S.h. Ko ◽

C.V. Nayar

Keyword(s):

Distributed Generation ◽

Voltage Source ◽

Design Consideration ◽

Voltage Source Inverter ◽

Generation System ◽

Control Approach ◽

Weak Grid

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Obtaining Robust Performance of a Current Fed Voltage Source Inverter for Virtual Inertia Response in a Low Short Circuit Ratio Condition

Energies ◽

10.3390/en14175546 ◽

2021 ◽

Vol 14 (17) ◽

pp. 5546

Author(s):

Clint Z. Ally ◽

Erik C. W. de Jong

Keyword(s):

Power Systems ◽

Short Circuit ◽

Pi Controller ◽

Voltage Source ◽

Current Loop ◽

Virtual Inertia ◽

Grid Connected Inverter ◽

Nominal Performance ◽

Inertia Response ◽

A Current

Low inertia levels are typical in island power systems due to the relatively small rotational generation. Displacing rotational generation units with static inertia-less PV power results in a significant increase in the frequency volatility. Virtual inertia provided by inverter-storage systems can resolve this issue. However, a low short circuit ratio (SCR) at the point of common coupling together with a fast phase locked loop (PLL) will compromise the response performance of the system. To address this issue, a robust PI controller (RPI) for the inner current-loop of a current fed grid-connected inverter is proposed. The PLL disturbance and grid impedance are incorporated into a single model and recast to a generalized representation of the system, thereby allowing easy tuning of the RPI by the mixed sensitivity H∞ method. The performance of the RPI is compared with that of a PI controller (PI) tuned by the regular loop-shaping method. The results show that when the SCR is above 10, the performance of both controllers is equivalent. However, lowering of the SCR compromises the performance of the system with PI and it becomes underdamped at SCR < 2. On the contrary, the system with the RPI is capable of maintaining the nominal performance throughout the same SCR decrease.

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