Resonance Interaction of Multiparallel Grid-Connected Inverters With LCL Filter

Lu, Ming–Feng; Wang, Xiongfei; Loh, Poh Chiang; Blaabjerg, Frede

doi:10.1109/tpel.2016.2585547

Cited by 145 publications

(92 citation statements)

References 12 publications

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“…One possible application of the proposed algorithm is to detect the interharmonic arising from parallel operations of grid-connected inverters with LCL filters. Fig.9 shows a typical setup based on the LCL filter parameters previously reported in [8]. The inverters are operated at a switching frequency of 3.78 kHz.…”

Section: E Further Discussionmentioning

confidence: 99%

“…Such resonance could result in not only voltage oscillations in the ac mains, but also system instability because the grid-connected inverter requires the mains voltage waveform for synchronization in the control loop. Recently, the resonance characteristics and stability problem caused by the interactions of multiple parallel LCL-filtered inverters has been reported in [8]. If resonance occurs, the control systems of the parallel power inverters should move their operating points out of the unstable zones.…”

Section: Introductionmentioning

confidence: 99%

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Online Detection of Fundamental and Interharmonics in AC Mains for Parallel Operation of Multiple Grid-Connected Power Converters

Chen

et al. 2018

IEEE Trans. Power Electron.

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Abstract-Parallel operation of multiple grid-connected power converters through LCL filters is known to have the potential problem of triggering oscillations in the ac mains. Such oscillatory frequencies are not integral multiples of the fundamental frequency and hence form a new source of interharmonics. Early detection of such oscillations is essential for the parallel power converters to move out of the unstable zone. This paper presents an online observer-based algorithm that can perform fast detection of interharmonics within a specified frequency band. The algorithm has been adopted in a specific and reduced form from an integral observer algorithm for detection of fundamental and interharmonic voltage components in the ac mains. A new method based on the kernel signal for fast interharmonic detection is proposed and practically verified. It has been implemented in a digital controller to detect oscillations such as those occurring between two grid-connected power converters. The practical results indicate that the algorithm can locate such frequency within the specific frequency band within 1 mains cycle.

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Section: E Further Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Online Detection of Fundamental and Interharmonics in AC Mains for Parallel Operation of Multiple Grid-Connected Power Converters

Chen

et al. 2018

IEEE Trans. Power Electron.

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“…The switch frequency is fsw, and the design equation of Li is given as: The LCL-filter has an outstanding performance of attenuating the switching noise, which is better than the L and LC-filters. In order to make the filter function well, the parameters of the filter have to be designed properly [1,18]. Section 2.1 shows the operation principles of the inverter, and the two buck converters share Cf, Lg1, and Lg2, which form a LCL filter.…”

Section: Inverter Side Inductor LImentioning

confidence: 99%

High Frequency Dual-Buck Full-Bridge Inverter Utilizing a Dual-Core MCU and Parallel Algorithm for Renewable Energy Applications

Meng¹,

Wang²,

Yang³

et al. 2017

Energies

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Abstract:A high frequency dual-buck full-bridge inverter for small power renewable energy applications is proposed in this paper. The implementation of the wide band gap SiC (Silicon Carbide) power device contributes to the high switching frequency of 400 kHz. This high frequency contributes to reduced converter volume as well as improved power density, which greatly strengthens its portability and application range. For the control strategy, a voltage-current dual loop controller is employed. A three-pole-three-zero (3P3Z) compensator is applied in the current loop in order to track the current reference without static error. A voltage loop two-pole two-zero (2P2Z) compensator is used to generate the current reference for stabilizing the DC bus voltage. Not only is the inner current loop analyzed in detail, which includes the modeling of the equivalent inductor-capacitor-inductor (LCL)-type inverter and the design of the 3P3Z compensator, but also the outer voltage loop is discussed, the model of which is established based on the energy balance. Furthermore, a feedback linearization method is adopted to simplify the duty cycle calculation and helps to accelerate the control speed. A second-order generalized integrator software phase lock loop (SOGI-SPLL) is employed to obtain the phase angle and to synchronize the inverter output current with the grid voltage. A parallel structure algorithm is conducted based on a dual-core microcontroller unit (MCU) for the first time to control the high frequency inverter. This approach avoids the contradiction between the high frequency operation and the limited computing capacity of the conventional single-core MCUs. The software structure, time-consuming distribution, and interactive communication method are analyzed in detailed. Finally, this paper verifies the feasibility of the theoretical analyses through simulation and experiments based on a 1 kW prototype.

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“…In [2], proposing a modeling and analysis method based on the current separation scheme, root locus in the discrete z-domain is used to analyze the resonance current appearing between the paralleled inverters, depending on current distribution and resonance characteristics. However, no effective suppression method is given.…”

Section: Introductionmentioning

confidence: 99%

Research on Resonance Mechanism and Suppression Technology of Photovoltaic Cluster Inverter

Wan

Zhang

2018

Energies

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Photovoltaic cluster power generation can improve the power generation efficiency of photovoltaic power plants, but the photovoltaic cluster inverter will produce resonance after the grid, affecting the safe and stable operation of power systems. In order to ensure the reliability of power supply, the resonant generation mechanism of photovoltaic cluster system is studied in this paper, and the resonant characteristics are analyzed, the control strategy of RC-type global resonance suppression and Thyristor Switching RC (TSRC) circuit are proposed, to suppress the resonance of the photovoltaic cluster system. The effectiveness of the control method is verified through simulation and experiment. The experimental results show that the resonance can be effectively suppressed, and the photovoltaic cluster system can be safely and stably connected to the power grid to ensure the reliability of power supply.

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Resonance Interaction of Multiparallel Grid-Connected Inverters With LCL Filter

Cited by 145 publications

References 12 publications

Online Detection of Fundamental and Interharmonics in AC Mains for Parallel Operation of Multiple Grid-Connected Power Converters

Online Detection of Fundamental and Interharmonics in AC Mains for Parallel Operation of Multiple Grid-Connected Power Converters

High Frequency Dual-Buck Full-Bridge Inverter Utilizing a Dual-Core MCU and Parallel Algorithm for Renewable Energy Applications

Research on Resonance Mechanism and Suppression Technology of Photovoltaic Cluster Inverter

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