The restrain of the dead time effects in parallel inverters

Zhang, Yu; Chen, Xikun; Kang, Yong; Chen, Jian

doi:10.1109/iemdc.2005.195813

Cited by 10 publications

(5 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To avoid the simultaneous turn-on of the two switching transistors in the same bridge of the inverter, leading to a shortthrough in the DC link, a dead time is employed in most control methods. The insertion of a dead time can ensure a reliable and safe inverter operation, but in practical engineering applications, it may cause load-dependent distortion in the inverter output voltages [1][2][3][4][5] and significant circulating currents between the parallelconnected units [6].…”

Section: Introductionmentioning

confidence: 99%

No dead‐time modulation algorithm for an off‐grid inverter based on H6 topology

Xia

Tian

Lü

et al. 2018

IET Power Electronics

View full text Add to dashboard Cite

In this study, a no-dead-time modulation method based on the H6 topology is proposed. The main objective is to reduce the total harmonic distortion (THD) of the inverter output voltage and improve the output-voltage waveform quality. On the basis of the working state of the main circuit, the proposed method selects an appropriate switch modulation, thereby realising the objective of not inserting a dead time, most of the time. Simulations and experiments demonstrate that the modulation method suppresses the THD better than the conventional modulation algorithm, at all power factors and power levels. Furthermore, with the increase in power, the output current increases, but the current commutation interval decreases and the output-voltage suppression effect THD is better. It can also be concluded that simultaneously there is a higher DC-link voltage utilisation efficiency in the no-dead-time modulation method than in the conventional modulation method.

show abstract

Section: Introductionmentioning

confidence: 99%

No dead‐time modulation algorithm for an off‐grid inverter based on H6 topology

Xia

Tian

Lü

et al. 2018

IET Power Electronics

View full text Add to dashboard Cite

show abstract

“…In (16), △I* g,αβ represents the effect of PLL on current reference. Substituting (14) into (16), △I* g,αβ is expressed as…”

Section: Model Of Pllmentioning

confidence: 99%

“…The effect of dead time on inverter output voltage and power quality was analysed by Fourier decomposition [11, 12]. Dead time was also viewed as an external disturbance in the research of grid‐connected inverters [13, 14]. The dead‐time effect alters the system equivalent impedance, which may cause inaccurate result.…”

Section: Introductionmentioning

confidence: 99%

Power quality and stability analysis of large‐scale grid‐connected photovoltaic system considering non‐linear effects

Zhang

Zhou

Mao

et al. 2018

IET Power Electronics

View full text Add to dashboard Cite

This study proposes to incorporate the non-linear factors, such as dead time and phase-locked loop (PLL), into the impedance model of large-scale grid-connected photovoltaic (PV) system and investigates their influence on the system power quality and stability considering the variation of PV capacity. The fundamental component of dead-time voltage can influence the inverter output impedance. The harmonics also have a vital effect on system power quality, especially when the inverter output admittance matches with the grid admittance. The increase of PV capacity can lower the influence of dead time on system phase margin, but may cause serious magnification of certain dead-time harmonics. PLL can make the system asymmetric and brings about the frequency coupling effect. The complex vectors and the transfer function matrix are used to convert the model of PLL from dq-to αβ-axis. The generalised Nyquist stability criterion is utilised to analyse the system stability. The variations of controller parameters in PLL can make the system oscillate. The increase of PV capacity may intensify this effect. Even the stable controller parameters are adopted, large PV capacity can trigger the system oscillation. Finally, the correctness of the theory is verified by simulation analysis and experiment.

show abstract

“…By far, the instantaneous feedback regulations with good effects on restraining the distortions include: PID control, dead-beat control, dual-loop controls with instantaneous current and voltage feedbacks, repetitive control, and so forth [3][4]. However, in our experiments of parallel inverters, the dead-time differences in power switches between inverters resulted in large harmonic circulating currents, and the restraining of them by instantaneous feedback regulations are limited because the filter inductances and parallel reactors in high power inverters must be small [5]. The traditional dynamic models of inverters tend to consider dead-time effects of power switches as equivalent resistances, which are included in r as shown in Fig.…”

mentioning

confidence: 99%

The Restrain of Harmonic Circulating Currents between Parallel Inverters

Zhang

Duan

Kang

et al. 2006

2006 CES/IEEE 5th International Power Electronics and Motion Control Conference

View full text Add to dashboard Cite

In inverters, distortions of output sine voltages caused by factors like dead-times of power switches can be well compensated by instantaneous voltages and/or currents feedback regulators such as PID or repetitive controllers. However, in our experiments, we found that the dead-time differences between inverters would result in significant harmonic circulating currents, and instantaneous regulators had limited effects on restraining them, esp. in large parallel power supply systems where the filter reactors and output impedances in each inverters must be small. In this paper, for analyses of harmonic circulating currents, an inverter model that considered the bias in SPWM voltage as a disturbance was established. The research on restraining of harmonic circulating currents by instantaneous feedback regulators indicated that there had been relationships in inverters between output voltage distortions and harmonic circulating currents. The experiments and simulations based on the duel loop voltage and current feedback controls demonstrated that instantaneous feedback regulators that achieve good waveforms could also lead to good restraining on the harmonic circulating currents.

show abstract

The restrain of the dead time effects in parallel inverters

Cited by 10 publications

References 4 publications

No dead‐time modulation algorithm for an off‐grid inverter based on H6 topology

No dead‐time modulation algorithm for an off‐grid inverter based on H6 topology

Power quality and stability analysis of large‐scale grid‐connected photovoltaic system considering non‐linear effects

The Restrain of Harmonic Circulating Currents between Parallel Inverters

Contact Info

Product

Resources

About