An Integrated Design Approach for LCL-Type Inverter to Improve Its Adaptation in Weak Grid

Chen, Zheng; Liu, Yajuan; Liu, Shuming; Li, Qionglin; Dai, Shuangyin; Tang, Yuzheng; Zhang, Bo; Mao, Mingxuan

doi:10.3390/en12132637

Cited by 5 publications

(6 citation statements)

References 36 publications

(84 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Moreover, the LCL filter has a dominant switching harmonic of 0.57%, which is expected since the LCL does not have a trap in the dominant switching frequency. On the other hand, the LLCL filter performs better in the dominant switching fre-FIGURE 9 Simulation results of the grid-tied inverter with LLCL filter (a) Simulation waveforms, (b) i g spectrum quency than the LCL filter but has the largest size among all the selected filters. The total volume of cores for the filters' inductors is calculated based on the area-product method [70].…”

Section: Simulation Resultsmentioning

confidence: 99%

“…It is worth mentioning that M ig and M gi are equal and thus can be referred to as M ig . Based on (8) and (9), it is noted that the two inductors are coupling with each other. According to (8), V i and V g can finally be described as:…”

Section: Expression Of Integrated Llcl Filter Inductorsmentioning

confidence: 99%

“…According to (9), the magnetic resistances determine the self and mutual inductances, which can be obtained as:…”

Section: Expression Of Integrated Llcl Filter Inductorsmentioning

confidence: 99%

“…In order to address the first issue, various modified configurations of LCL filters have been presented [4][5][6][7][8][9][10][11][12][13][14][15][16]. These modified filters have additional components such as resonant LC traps connected in series or parallel, which are resonated at the switching frequency and its multiples to bypass or block the selected harmonics by these LC traps.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Magnetic integrated LLCL filter with resonant frequency above Nyquist frequency

Al-Barashi

Liu

et al. 2022

IET Power Electronics

View full text Add to dashboard Cite

This paper presents a design technique of magnetic integrated LLCL filters for grid-tied inverters. With the proposed design technique, the LLCL filter's resonant frequency can be higher than the Nyquist frequency. Furthermore, the proposed concept was only reported for the LCL filter in the previous research works. In addition, the modulation process will produce dominant switching harmonics for unipolar PWM H-bridge inverters at the double switching frequency. Thus, putting the resonant frequency beyond the Nyquist frequency will increase the stability zone. The proposed design methods maximize the filter inductors' utilization and resist the grid impedance variations under weak grid conditions, depending on the improved stability zone. Comparative simulation and HIL experimental results are presented to confirm the effectiveness of the proposed magnetic integrated LLCL filter design. The HIL experimental results and the simulation results agree well with each other.

show abstract

Section: Simulation Resultsmentioning

confidence: 99%

Section: Expression Of Integrated Llcl Filter Inductorsmentioning

confidence: 99%

“…According to (9), the magnetic resistances determine the self and mutual inductances, which can be obtained as:…”

Section: Expression Of Integrated Llcl Filter Inductorsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Magnetic integrated LLCL filter with resonant frequency above Nyquist frequency

Al-Barashi

Liu

et al. 2022

IET Power Electronics

View full text Add to dashboard Cite

show abstract

“…Typically, the traction transformer (TT) leakage inductance has been used as the inductance of the grid-side converter for maximizing the utilization of the iron core while also meeting the criteria for compact size and low weight in HST equipment [11]. In [12][13][14][15][16][17][18][19][20][21][22][23], various configurations of LCLmodified filters have been presented. Many of these filters have additional LC traps, resonant tanks in series or parallel, resonated at the switching frequencies and their multiples, which allows bypassing or blocking specified harmonics via those traps.…”

Section: Introductionmentioning

confidence: 99%

Enhancing power quality of high‐speed railway traction converters by fully integrated T‐LCL filter

Al-Barashi

Meng

Liu

et al. 2022

IET Power Electronics

View full text Add to dashboard Cite

Modulating the traction converters produces current harmonics at the switching frequencies and their multiples. These harmonics should be minimized to meet the network specifications. The LC‐trapped filters, tuned to these frequencies, can easily meet this requirement, but the existing applicable trap filters have not been studied with the traditional traction system topologies. Thus, this paper presents a trapped LCL filter with an LC resonator on the converter side, called a fully integrated T‐LCL filter, for the traction power supply system. The model and analysis reported in this research demonstrate that the presented filter has several advantages, which can be summarized by: reducing the size by winding many coils through magnetic integration, attenuating the switching frequency and its multiple harmonics that reduce the current total harmonic distortion, assuring durability against the filter parameters differences, and preserving system stability under transient conditions. The proposed filter can become a promising trap filter based on these advantages. Simulation models of an ac/dc single‐phase traction rectifier with the proposed filter were created and tested in MATLAB/Simulink, verifying its superiority. Finally, the filter is validated by performing hardware‐in‐the‐loop experiments.

show abstract

Magnetic integrated double-trap filter utilizing the mutual inductance for reducing current harmonics in high-speed railway traction inverters

Al-Barashi,

Wang,

Lan

et al. 2024

Sci Rep

View full text Add to dashboard Cite

Current harmonics are generated at the switching frequency and its multiples when the traction converters are modulated. To address this, multi-trap filters are introduced, which are capable of selectively eliminating these specific harmonics to the limits set by IEEE 519-2014. This targeted removal significantly reduces the need for high total inductance, thereby allowing for a more compact filter design. Comparatively, to traditional inductor-capacitor-inductor (LCL) filters, more magnetic cores are needed for trap inductors. Furthermore, the traction systems have not been examined in conjunction with multi-trap filters. To reduce the filter size and investigate its application in traction converters, this paper presents an integrated double-trap LCL (DTLCL) filter. A tiny capacitor is connected in parallel with the grid-side inductor to form one LC-trap. In addition, another LC-trap is formed by connecting the equivalent trap inductor, introduced through the magnetic coupling between inverter-side and grid-side inductors, in series with the filter capacitor. The presented filters' features are thoroughly analyzed, and the design method has been developed. Finally, the simulation and hardware-in-the-loop (HIL) experiment results validate the proposed method's viability and efficacy. Compared to the discrete windings, the integrated ones enable a size decrease of two cores. Furthermore, the proposed filters can meet IEEE 519-2014 criteria with 0.3% for all the current switching harmonics and total harmonic distortion (THD) of 2.36% of the grid‐side current.

show abstract

An Integrated Design Approach for LCL-Type Inverter to Improve Its Adaptation in Weak Grid

Cited by 5 publications

References 36 publications

Magnetic integrated LLCL filter with resonant frequency above Nyquist frequency

Magnetic integrated LLCL filter with resonant frequency above Nyquist frequency

Enhancing power quality of high‐speed railway traction converters by fully integrated T‐LCL filter

Magnetic integrated double-trap filter utilizing the mutual inductance for reducing current harmonics in high-speed railway traction inverters

Contact Info

Product

Resources

About