A Comparison of Instantaneous and Extension p-q Methods for Current Controlled Voltage Source Inverter in Microgrid

Objective:This paper analyses the Modular Multilevel Converter (MMC) topology, where each individual Sub Module (SM), in half bridge configuration, is directly fed by an elementary electrochemical cell.Methods:The aim is to investigate how the reference voltages influence the cells currents waveforms, determining how the active powers and the losses are distributed among the cells. Considering a 2-level Voltage Source Inverter (VSI) topology working in the same conditions, the ratio between the MMC total cells losses and VSI total cells losses is calculated. After showing the system architecture and mathematical model, the cells current waveform investigation is presented and detailed both for triangular and sinusoidal voltage reference waveform.Results:Finally, the results are critically discussed with particular focus on the comparison between the MMC and the VSI topologies.

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Effect of the Modulation Index and the Carrier Frequency on the Output Vol Tage Waveform of the Spwm Voltage Source Inverter

2020 17th International Multi-Conference on Systems, Signals & Devices (SSD) ◽

10.1109/ssd49366.2020.9364104 ◽

2020 ◽

Author(s):

Ibrahim. M. Al-Adwan ◽

Yasin. A. Al Shiboul

Keyword(s):

Carrier Frequency ◽

Modulation Index ◽

Voltage Source ◽

Voltage Source Inverter

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Dual Two-Level Voltage Source Inverter Virtual Inertia Emulation: A Comparative Study

Energies ◽

10.3390/en14041160 ◽

2021 ◽

Vol 14 (4) ◽

pp. 1160

Author(s):

Mohammad Ali Dashtaki ◽

Hamed Nafisi ◽

Amir Khorsandi ◽

Mojgan Hojabri ◽

Edris Pouresmaeil

Keyword(s):

Harmonic Distortion ◽

Synchronous Generator ◽

Voltage Source ◽

Small Signal ◽

Voltage Source Inverter ◽

Nonlinear Loads ◽

Virtual Inertia ◽

The Stability ◽

Stability Enhancement ◽

Oscillation Damping

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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