Mathematical model of five-level ac/dc converter in abc reference frame

Nakka, Jayaram; Agarwal, Pramod; Das, Sharmili

doi:10.1016/j.ijepes.2014.04.057

Cited by 10 publications

(10 citation statements)

References 12 publications

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“…For the proposed analysis, the switching function for each leg of a HBC in a phase has been found by using basic cubic curve fitting . Aimed at precise working of the system, power switches present in HBC are controlled such as two switches in a HBC leg should not be ON at the same time . In a phase, if isolated input dc voltage sources for both HBC are assumed identical, then the two capacitors of the corresponding HBC fairly share half of the total dc link voltage ( V dcx ).…”

Section: Proposed Wecs Descriptionmentioning

confidence: 99%

“…In the present system, inconsistency of wind speeds at each turbine causes distinct voltage conditions among the isolated dc links of the CHBMLI. “ V acx ” is obtained by adding each HBC ac side voltage algebraically and can be obtained from Equation .

S_{y} = ({, \begin{array}{l} 1 italicif S_{italicpx 1}, S_{italicnx 1}, S_{italicpx 2} italicand S_{italicnx 2} = 1 \\ \frac{true}{1} italicif ({, \begin{array}{l} italiccase - 1 S_{italicpx 1}, S_{italicnx 1} = 1 italicand ((), S_{italicpx 2} & S_{italicnx 2}) italicare italicof opposite italicsign \\ italiccase - 2 S_{italicpx 2}, S_{italicnx 2} = 1 italicand ((), S_{italicpx 1} & S_{italicnx 1}) italicare italicof opposite italicsign \end{array}) \\ 0 italicif ({, \begin{array}{l} italiccase - 1 S_{italicpx 2}, S_{italicnx 2} = 1 italicand ((), S_{italicpx 1} & S_{italicnx 1}) italicare italicof opposite italicsign \\ italiccase - 2 S_{italicpx 1}, S_{italicnx 1} = 1 italicand ((), S_{italicpx 2} & S_{italicnx 2}) italicare italicof opposite italicsign \\ italiccase - 3 ((), S_{italicpx 1} & S_{italicnx 1}) \end{array}) \end{array})

…”

Section: Proposed Wecs Descriptionmentioning

confidence: 99%

See 1 more Smart Citation

Capacitor voltage balancing in cascaded H‐bridge multilevel inverter and its modelling analysis for grid integrated wind energy conversion system application

Sharma

Dahiya

Nakka

2019

Circuit Theory & Apps

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windmills may operate at variable speeds. 5 Because of variable speed operation and better performance, the doubly fed induction generator (DFIG) has been conventionally used in WECSs. However, permanent magnet synchronous generator (PMSG) has gained broad attention in wind energy applications due to its high efficiency operation, extended speed operating range, self-excitation capability, and leading to a high power factor. For obtaining high efficiency in WECS, it is essential to manage WT such that they can produce maximum power. MPPT algorithm is required for maximal power extraction from the wind energy sources (WES). 1,[6][7][8][9] The output of wind turbine generator (WTG) coupling are inherently unstable dc voltage. The unstable output of WTG contribute to the power quality and stability issues like voltage variations, harmonic generation, and flickers in the grid network. Unwanted harmonics are produced due to the presence of power converters. In addition, due to the varying wind speed, flicker or voltage variation occurs in output power supply. Thus, for the grid integration of WECS, the need of advanced power electronic converters (rectifier, boost converters, and inverters) under transient and steady-state operating condition configuration and their proficient control are necessary to standardize the converter output voltage, even under changing environmental conditions. 3,10 Nowadays, in this type of applications, the multilevel inverters are mostly used in comparison to elementary two-level inverters due to several advantages. [11][12][13][14] Among all standard MLI topologies, "cascaded H-bridge inverter (CHBI)" is primarily used for grid-integrated WECS applications owing to its simpler layout, modular design, reduced number of components as compared with other classical MLI topologies and the use of low voltage rated switches for achieving high or medium power level. [14][15][16][17][18][19] In proposed WECS, WTG coupled systems are connected to two individual H-bridges per phase of CHBMLI through isolated dc link along with respective independent boost converter-based maximum power point tracking (MPPT) system. In addition, by cascading these two H-bridges, the desired five-level output phase voltage is obtained.The major advantage of adopted CHBMLI topology possessing the isolated dc links plays the prominent role to legitimate in connecting two WECS with unequivocal power generation because of deviation of the wind speeds among the windmills at any point of time. In addition, this MLI support to adjoin two medium voltage WECS to feed the total power generated into the high voltage grid without any transformers, but at the same time, the system achieves the better synchronization along with calibrated and controlled power flow. It is an important note to consider that either the CHB topology used as an inverter or a rectifier the mandate of possessing equal dc link voltages is essential to justify identical permissible voltage stress among all switching devices in multilevel topologies at high ...

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Section: Proposed Wecs Descriptionmentioning

confidence: 99%

S_{y} = ({, \begin{array}{l} 1 italicif S_{italicpx 1}, S_{italicnx 1}, S_{italicpx 2} italicand S_{italicnx 2} = 1 \\ \frac{true}{1} italicif ({, \begin{array}{l} italiccase - 1 S_{italicpx 1}, S_{italicnx 1} = 1 italicand ((), S_{italicpx 2} & S_{italicnx 2}) italicare italicof opposite italicsign \\ italiccase - 2 S_{italicpx 2}, S_{italicnx 2} = 1 italicand ((), S_{italicpx 1} & S_{italicnx 1}) italicare italicof opposite italicsign \end{array}) \\ 0 italicif ({, \begin{array}{l} italiccase - 1 S_{italicpx 2}, S_{italicnx 2} = 1 italicand ((), S_{italicpx 1} & S_{italicnx 1}) italicare italicof opposite italicsign \\ italiccase - 2 S_{italicpx 1}, S_{italicnx 1} = 1 italicand ((), S_{italicpx 2} & S_{italicnx 2}) italicare italicof opposite italicsign \\ italiccase - 3 ((), S_{italicpx 1} & S_{italicnx 1}) \end{array}) \end{array})

…”

Section: Proposed Wecs Descriptionmentioning

confidence: 99%

Capacitor voltage balancing in cascaded H‐bridge multilevel inverter and its modelling analysis for grid integrated wind energy conversion system application

Sharma

Dahiya

Nakka

2019

Circuit Theory & Apps

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“…where 1 , 1 , and 1 denote the fundamental currents of phases A, B, and C, respectively, and 0 1 and 0 2 are the two dc voltages across 1 (6) Evaluate (19), and the fundamental positive ( 1 1 ), negative ( 1 2 ), and zero sequence ( 1 0 ) currents and the two dc voltages are stated as (26). Figure 10 shows the harmonic spectra of this unbalanced case in terms of positive and negative sequence components.…”

Section: Case Studiesmentioning

confidence: 99%

“…However, all the high-order harmonics are effectively eliminated in averaging operations, thereby producing inaccurate harmonic results. Jayaram et al [19] derived a five-level DCM-VSC in abc frame for which the switching functions are obtained using curve fitting. However, such a model becomes very complex when the number of level is high.…”

Section: Introductionmentioning

confidence: 99%

Harmonic Modeling of a Diode-Clamped Multilevel Voltage Source Converter for Predicting Uncharacteristic Harmonics

Huang

Lian

2018

Mathematical Problems in Engineering

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In response to the growing demand for medium-and high-power trends, multilevel voltage source converters (VSCs) have been attracting growing considerations. One of the widely used VSCs are the diode-clamped multilevel VSC (DCM-VSC). As these converters proliferate, their harmonic impact may become significant. Nevertheless, a harmonic model for the DCM-VSC is currently lacking in the literature. In this paper, the ABCD matrix, mapping the input harmonics to the output harmonics of DCM-VSC, is derived. As the matrix is formulated in the time-domain, the output harmonics are exact and do not suffer from harmonic truncation errors. As the paper will demonstrate, the derived ABCD matrix can be easily applied to a microgrid system and users can easily predict all the uncharacteristic harmonics when a microgrid is subjected to various conditions of imbalance. In addition to all the results being validated with those of PSCAD/EMTDC, the computation time of the proposed method is in contrast much shorter.

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“…Therefore, MLCs can reduce the operating switching frequency of ac-dc converter, which can improve the efficacy of the power electronics system. The superior features offered by MLCs leads to a significant penetration in areas like flexible AC transmission system (FACTS), harmonic active power filters, traction drives and hybrid electric vehicles, uninterruptible power supplies, ac motor drive, applications like pumps, fans, compressors and conveyors for industries like mining, marine, oil and gas, metal and so on [1][2][3][4][5][6][7][8][9]. Given their superior features, including sinusoidal input current at unity power factor and high-quality dc output voltage with a filter capacitor of small size, MLCs are receiving much more and wider attention both in terms of topologies and control schemes.…”

Section: Introductionmentioning

confidence: 99%

New MPC‐5LUC with reduced PSD count for MVHP direct‐drive WECS with PMSG: a cost‐effective solution

Yalla

Agarwal

2019

IET Electric Power Applications

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In this study, a new multi-point clamped (MPC), three-phase two-leg, five-level unidirectional front end high-powerfactor converter is proposed for directly connected wind energy conversion system with a permanent magnet synchronous generator. The proposed topology can be modelled and modulated similarly to other existing MPC structured converters with the omission of clamping diodes and bidirectional switches. The proposed converter has an advantage of reduced power semiconductor device count and maximum device stress. A factor (normalised index) is introduced and comprehensive comparative analysis with N level existing topologies is carried out. The minimum value of the normalised index makes the proposed topology as a suitable option for medium-voltage and high-power applications. Also, the fault ride through capability is one of the key performance indicators is also investigated on proposed topology under voltage sag condition. Further, steady state and transient performance of topology during load as well as dc-link voltage change are presented. Minimum distorted and balanced line currents with unity power factor are drawn from supply by implementing negative sequence elimination control algorithm. The validation of proposed topology is verified with simulation and a down-scaled experimental setup.

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Mathematical model of five-level ac/dc converter in abc reference frame

Cited by 10 publications

References 12 publications

Capacitor voltage balancing in cascaded H‐bridge multilevel inverter and its modelling analysis for grid integrated wind energy conversion system application

Capacitor voltage balancing in cascaded H‐bridge multilevel inverter and its modelling analysis for grid integrated wind energy conversion system application

Harmonic Modeling of a Diode-Clamped Multilevel Voltage Source Converter for Predicting Uncharacteristic Harmonics

New MPC‐5LUC with reduced PSD count for MVHP direct‐drive WECS with PMSG: a cost‐effective solution

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