Plug-and-Play Voltage Ripple Mitigator for DC Links in Hybrid AC–DC Power Grids With Local Bus-Voltage Control

Harmonics generated from power electronic converters will impose significant power quality challenges to the electric grid onboard future aircraft. In this paper, we propose an innovative modulation scheme that enables using a buck-boost DC-DC converter as a harmonic absorber. To demonstrate the effectiveness of the proposed method, a hybrid power generation system involving a high-speed electrical generator and a high voltage battery is introduced. The electrical generator is connected to a DC bus through an AC-DC converter and the battery to the DC bus with a DC-DC converter. For the studied hybrid power generation system, it is identified that the first carrier frequency side-band harmonic (fc-3f0) from the AC-DC converter is most relevant and is targeted for cancellation. For the control of the DC-DC converter, a new modulation technique, called equal-gate-width (EGW) modulation is proposed. It allows active control of the magnitude and phase angle of some specific harmonic components from a DC-DC converter. By properly tuning the phase angle and amplitude, the controlled harmonics can thus be used to cancel harmonics from other converters on a common DC bus. Without losing generality, the paper focuses on the development of this specific harmonic cancellation scheme and the effectiveness of our proposed methods has been demonstrated using experimental results.

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“…2c, another significant harmonic exists in 2fc. In [14], the magnitude of this component is analyzed and simplified as…”

Section: Component Selection For Suppressionmentioning

confidence: 99%

“…Adding additional circuits is the most direct method [11]- [14]. In those cases, additional switching devices were added to the system and harmonics on capacitors were effectively reduced with an adjustable switching operation of the extra switches.…”

Section: Introductionmentioning

confidence: 99%

Using DC–DC Converters as Active Harmonic Suppression Device for More Electric Aircraft Applications

Wang

Yang

Hussaini

et al. 2022

IEEE Trans. Ind. Electron.

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“…It distorts the reference current and causes an excessive third-order harmonic current to be injected into the grid. This problem is solved via power decoupling [3][4][5][6][7][8][9] or by improving the control scheme without additional circuits [10][11][12][13][14][15][16][17]. However, according to engineering design concepts, improving the control strategy without additional circuits is more interesting because it is simpler to implement, has lower cost, has no additional power loss, and does not complicate the overall circuitry.…”

Section: Introductionmentioning

confidence: 99%

Effective low‐cost solution using cascaded connection of two modified notch filters to mitigate the second and third harmonic currents in single‐phase dual‐stage half‐bridge microinverter

Vongkoon

Liutanakul

Wiwatcharagoses

2019

IET Power Electronics

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On the grid side, the half-bridge topology of the microinverter is of interest for solar rooftop applications because of its high efficiency, low component count, and cost-effectiveness. However, it has an inherent double-line frequency ripple voltage on the dc-link, which causes the injection of a third-order harmonic current when the voltage control loop is closed. Furthermore, in practice, different average voltages or different capacitances of the two capacitors at the dc-link produce a second-order harmonic current that flows into the grid. In this paper, the analytical details of these harmonics are comprehensively described, and a simple and effective low-cost technique using the cascaded connection of two modified notch filters is proposed in the voltage control loop to mitigate their effects. The simulation and experimental results of a 300 W microinverter indicate that the proposed filters represent an effective low-cost solution and perform well in accordance with the IEEE 1547 standard, even if the capacitances at the dc-link are mismatched by 20%. Besides, the prototype is tested when occurring of the changing +1% of the line frequency, or appearing of the distorted waveform of grid voltage with the composition of 6% of fifth-order harmonic. Nomenclature Capital boldface italic letters such as V, represent phasors. Capital italic letters such as C 1 , represent constant variables. Small italic letters such as v dc (t), represent instantaneous variables depending on time. Small italic letters such as ṽ dc (t), represent small ac signals in the time domain. Capital italic letters such as G vp (s), represent transfer functions in the s-domain. Small italic letters such as v dc (s), represent signal variables in the s-domain.

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“…This approach effectively restricts the resonance peak value, accelerates the transfer speed, and maintains steady filtering results. Simulation and test results verify that the filter has low resonance value, rapid convergence ability, and an excellent filtering effect.Energies 2018, 11, 3128 2 of 20 into two categories: active power filtering (APF) [19][20][21][22][23] and passive power filtering (PPF) [24][25][26][27][28][29]. APF can eliminate DC voltage fluctuation dynamically by paralleling the voltage converter on the DC side.…”

mentioning

confidence: 99%

“…However, the ability of this method to eliminate voltage harmonics is limited considering the restricted power of non-critical loads. In Li et al [19], a pluggable voltage pulsation suppression device was designed to realize flexible control of the voltage ripple in an AC/DC hybrid distribution network. However, adding a device at each node evidently increased the cost of investment.…”

mentioning

confidence: 99%

Design of Low-Ripple and Fast-Response DC Filters in DC Distribution Networks

2018

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The design and parameter selection of low-ripple and fast-response direct current (DC) filters are discussed in this study with the aim of alleviating the influence of a DC-side low-frequency voltage pulsation on a sensitive load in a DC distribution network. A method for determining the DC filter parameters by using a mofatching most flat response algorithm is presented. The voltage transfer function of the DC-side filter in the DC distribution network is deduced to analyze its voltage transfer characteristics. The resonance peak value of the filter network is an important factor affecting the transfer speed of a filter. A pole-circle-based parameter optimization method is proposed to move the poles of the filter transfer function down and to the left of pole plane for finding the appropriate capacitance, inductance, and damping parameters. This approach effectively restricts the resonance peak value, accelerates the transfer speed, and maintains steady filtering results. Simulation and test results verify that the filter has low resonance value, rapid convergence ability, and an excellent filtering effect.Energies 2018, 11, 3128 2 of 20 into two categories: active power filtering (APF) [19][20][21][22][23] and passive power filtering (PPF) [24][25][26][27][28][29]. APF can eliminate DC voltage fluctuation dynamically by paralleling the voltage converter on the DC side. For example, Wang et al. [20] proposed eliminating harmonics in the DC bus voltage with a DC electric spring. This approach adjusts the consumption power of a non-critical load to make it follow the power variation of renewable energy. However, the ability of this method to eliminate voltage harmonics is limited considering the restricted power of non-critical loads. In Li et al. [19], a pluggable voltage pulsation suppression device was designed to realize flexible control of the voltage ripple in an AC/DC hybrid distribution network. However, adding a device at each node evidently increased the cost of investment. Lee et al. [21] suggested suppressing DC voltage pulsation using an energy storage device in the DC distribution network and controlling the converters. However, the control method is complex and the operation and maintenance costs of the energy storage device are high. In Li et al.[23], a ripple eliminator, which is a bidirectional buck-boost converter terminated with an auxiliary capacitor, was adopted to replace bulky capacitors in DC systems. Although the APF is effective at eliminating voltage harmonics, designing and controlling DC APF is complex and costly [22]. In addition, APF is rarely used in DC distribution networks with large capacity and high voltage given its limitations. The DC passive filter design is simple without the additional of a controller, acting as the main DC voltage filter in the DC distribution network. DC passive filters are mainly divided into tuned and low-pass filters. The former has a large occupational area and minimal flexibility [27]. The latter can filter the harmonics after a cut-off frequency...

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Plug-and-Play Voltage Ripple Mitigator for DC Links in Hybrid AC–DC Power Grids With Local Bus-Voltage Control

Cited by 56 publications

References 42 publications

Using DC–DC Converters as Active Harmonic Suppression Device for More Electric Aircraft Applications

Using DC–DC Converters as Active Harmonic Suppression Device for More Electric Aircraft Applications

Effective low‐cost solution using cascaded connection of two modified notch filters to mitigate the second and third harmonic currents in single‐phase dual‐stage half‐bridge microinverter

Design of Low-Ripple and Fast-Response DC Filters in DC Distribution Networks

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