Identification of resonances in parallel connected grid inverters with LC- and LCL-filters

Juntunen, Raimo; Korhonen, Juhamatti; Musikka, Tatu; Smirnova, Liudmila; Pyrhönen, Olli; Silventoinen, Pertti

doi:10.1109/apec.2015.7104642

Cited by 12 publications

(7 citation statements)

References 20 publications

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“…If the Z g =0, G plant = G coupling , thus the non-diagonal G12 is equal to zero according to (2) and (3). It means that there is no mutual coupling effect among these inverters.…”

Section: A Modeling Based On Current Separationmentioning

confidence: 99%

“…For filtering out the high-frequency harmonics from these inverters, the third-order LCL-filters has demonstrated better attenuation ability than the L-filter with a smaller size and lower cost. However, the LCL-filter resonance may lead to instability of current control [2], [3]. In renewable power plants, it is common to have hundreds or even thousands of inverters operating in parallel to scale up the total generation capacity.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Resonance Interaction of Multiparallel Grid-Connected Inverters With LCL Filter

Wang

Loh

et al. 2017

IEEE Trans. Power Electron.

145

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This letter investigates the resonance characteristics and stability problem caused by the interactions of multi-parallel LCL-filtered inverters. Compared to single grid-connected inverter, the multi-inverter system presents a more challenging resonance issue, where the inverter interactions may excite multiple resonances at various frequencies. This letter proposes a modeling and analysis method based on the current separation scheme. It reveals that an interactive resonant current that circulates between the paralleled three-phase inverters may arise, depending on the current distribution and the system resonance characteristics. This is different from the common resonant current injected into the grid and has yet been discussed before. The analysis with the root loci in the discrete z-domain are carried out with two stability constraints identified, which correspond to the conditions of triggering the interactive resonant current and common resonant current, respectively. Simulations and experimental results verify the theoretical analysis.Index Terms-Multi-parallel inverters, LCL-filter, resonance interaction, stability analysis.

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“…If the Z g =0, G plant = G coupling , thus the non-diagonal G12 is equal to zero according to (2) and (3). It means that there is no mutual coupling effect among these inverters.…”

Section: A Modeling Based On Current Separationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Resonance Interaction of Multiparallel Grid-Connected Inverters With LCL Filter

Wang

Loh

et al. 2017

IEEE Trans. Power Electron.

145

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show abstract

“…In terms of the filter circuit, there are three common types of filter, which are the first‐order L filter, the second‐order low pass filter of L ‐ C , and the third‐order filter of the L ‐ C ‐ L filter. The first type is mainly for the current‐controlled mode of the voltage source converter, while the other two types are used for the voltage‐controlled mode of the voltage source converter, 20 which is the focus of this presented paper The cut‐off frequency for both filters is given as 21

\begin{matrix} lefttrue \\ ω_{LC - filter} = \frac{1}{\sqrt{LC}}, \\ ω_{LCL - filter} = \frac{1}{\sqrt{((), L_{1} + L_{2}) C}} . \end{matrix}

…”

Section: Filter Circuitmentioning

confidence: 99%

Experimental verification for improved phase‐disposition PWM of three‐phase five‐level diode‐clamped inverter

Suleiman

Elnady

Osman

2021

Circuit Theory & Apps

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This paper focuses on the design and practical implementation of the effective and improved switching modulation and filter circuits for a three-phase fivelevel diode-clamped inverter. The proposed switching modulation circuits illustrate the three-phase control signals, carrier signals, and signals for drive circuits. The paper presents also an efficient control and drive circuits, which are used to operate the power switches (power MOSFETs). An improved analog dead-band circuit is practically analyzed and implemented to minimize the overlapping periods of any two complement power switches and consequently reduce the noise/spikes caused by those overlapping periods. The proposed improved switching modulation circuit is verified by simulation results along with their analogous experimental results for the switching modulation, control circuits, and power circuits.

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“…One of the challenges encountered by grid-connected inverters is the instability due to the uncertainty and variation grid impedance in a weak grid [3][4][5][6]. It has been revealed that the interaction between inverter and grid impedance is the main reason for that problem [7][8][9][10]. Additionally, some solutions have been proposed to cope with this issue from different perspectives.…”

Section: Introductionmentioning

confidence: 99%

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

Chen¹,

Liu²,

Liu³

et al. 2019

Energies

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To improve the robustness of grid-connected inverter against grid impedance in a weak grid an integrated design method of LCL-filter parameters and controller parameters is proposed. In the method the inherent relation of LCL-filter parameters and controller parameters is taken into consideration to realize their optimized match. A parameter normalization scheme is also developed to facilitate the system stability and robustness analysis. Based on the method all normalization parameters can be designed succinctly according to the required stability and robustness. Additionally, the LCL parameter and controller parameter can be achieved immediately by restoring normalization parameters. The proposed design method can guarantee the inverter stability and robustness simultaneously without needing any compensation network, additional hardware, or the complicated iterative computations which cannot be avoided for the conventional inverter design method. Simulation and experiment results have validated the superiority of the proposed inverter design method.

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Identification of resonances in parallel connected grid inverters with LC- and LCL-filters

Cited by 12 publications

References 20 publications

Resonance Interaction of Multiparallel Grid-Connected Inverters With LCL Filter

Resonance Interaction of Multiparallel Grid-Connected Inverters With LCL Filter

Experimental verification for improved phase‐disposition PWM of three‐phase five‐level diode‐clamped inverter

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

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