Research on Unbalance Fault-Tolerant Control Strategy of Modular Multilevel Photovoltaic Grid-Connected Inverter

Liu, Yiqi; Li, Danhua; Jin, Yu; Wang, Qingbo; Song, Wenlong

doi:10.3390/en11061368

Cited by 4 publications

(3 citation statements)

References 39 publications

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“…In [20], an effective control strategy including fault detection, localization, and tolerant operation was proposed for a modular multi-level converter with a transistor open-circuit fault; however, this method is only applicable to a large number of series-connected two-level converter modules, and only for AC-to-DC converters. A novel fault-tolerant control strategy was proposed in [21] for bypassing converter submodules (SM) with faults and re-regulating the SM capacitor voltage and carrier phase-shift angle to maintain the main components of circulating current, additionally reducing the total harmonic distortion (THD) of the grid-connected current to enable the stable operation of the photovoltaic inverter; however, this method is also only suitable for a large number of series-connected two-level inverters. A detailed analysis of a single open-switch fault for a NPC active rectifier was presented in [22].…”

Section: Introductionmentioning

confidence: 99%

Fault Diagnosis and Tolerant Control of Three-Level Neutral-Point Clamped Inverters in Motor Drives

Chao

2020

Energies

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This paper presents an extension theory-based assessment method to perform fault diagnosis for inverters in motor driving systems. First, a three-level neutral-point clamped (NPC) inverter is created using the PSIM software package to simulate faults for any power transistor in the NPC-type inverter. Fast Fourier transformation is used to transform the line current signals in the time domain into a spectrum in the frequency domain for analysis of the corresponding spectrum of features of the inverter for faults with different power transistors. Then, the relationships between fault types and specific spectra are established as characteristics for the extension assessment method, which is then used to create a smart fault diagnosis system for inverters. Fault-tolerant control (FTC) is used here when the rated output of a faulty inverter is decreased in order to maintain balanced output in three phases by changing the framework of the transistor connection. This is performed to reinforce the reliability of the inverter. Finally, by the simulation and experimental results, the feasibility of the proposed smart fault diagnosis system is confirmed. The proposed fault diagnosis method is advantageous due to its minimal use of data and lack of a learning process, which thereby reduces the fault diagnosis time and makes the method easily used in practice. The proposed fault-tolerant control strategy allows both online and smooth switching in the wiring structure of the inverter.

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Section: Introductionmentioning

confidence: 99%

Fault Diagnosis and Tolerant Control of Three-Level Neutral-Point Clamped Inverters in Motor Drives

Chao

2020

Energies

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“…There are many fault-tolerant control strategies when an open circuit fault occurs. Fault-tolerant control strategies have been proposed for diodes of NPC (neutral point clamped) inverters [31], flying-span capacitor inverters [32], cascade multilevel inverters [33,34], T-type three-level inverters [35,36], etc.. Additional TRIACS (TRIode alternating current semiconductor) are added for fault-tolerant operations [31][32][33][34][35][36][37][38].…”

Section: Introductionmentioning

confidence: 99%

A Secondary Reconfigurable Inverter and Its Control Strategy

Xiang

Chen

2020

Applied Sciences

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This article proposes a topology of the secondary reconfigurable inverter and the corresponding fault-tolerant control strategy. When the secondary reconfigurable inverter is operating normally, its topology structure is the TPSS circuit. When the power semiconductor devices in the inverter are faulty, the inverter circuit needs to be reconfigured. After removing the faulty power semiconductor devices, the remaining power semiconductor devices and the DC side powers are reconstructed as the TPFS structure to keep the system running normally. This article also proposes a switch-pulse-resetting algorithm. This paper adopts the control strategy connecting the constant-voltage, constant-frequency control method with the switch pulse resetting algorithm. It need not change the control algorithm when the proposed reconfigurable inverter is transformed from the normal running state into the faulty running state. The inverter dependability is greatly improved. Finally, the feasibility and effectiveness of the proposed second reconfigurable inverter topology and control strategy are verified by simulation and experiment.

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“…If the SM faults in the system are not handled in time, there will be large deviations in the fault SM voltage, causing overload of other devices or SMs in the system. Thus, the non-fault phase may be impacted, and the overall output performance of the system will be affected [3][4][5]. Therefore, the fault-tolerant control after SM fault is of great importance.…”

Section: Introductionmentioning

confidence: 99%

A Fault-Tolerant Control Strategy of Modular Multilevel Converter with Sub-Module Faults Based on Neutral Point Compound Shift

et al. 2019

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In view of the complex calculation and limited fault tolerance capability of existing neutral point shift control algorithms, this paper studies the fault-tolerant control method for sub-module faults in modular multilevel converters on the basis of neutral point compound shift control strategy. In order to reduce the calculation complexity of shift parameters in the traditional strategy and simplify its implementation, an improved AC side phase voltage vector reconstruction method is proposed, achieving online real-time calculation of the modulation wave adjustment parameters of each phase required for fault-tolerant control. Based on this, a neutral point DC side shift control method is proposed to further improve the fault tolerance capability of the modular multilevel converter (MMC) system by compensating the fault phase voltage with non-fault phase voltage. By means of the compound shift control strategy of the DC side and AC side of the neutral point, an optimal neutral point position is selected to ensure that the MMC system output line voltage is symmetrical and the amplitude is as large as possible after fault-tolerant control. Finally, the effectiveness and feasibility of the proposed control strategy are verified by simulation and low-power MMC experimental system testing.

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Research on Unbalance Fault-Tolerant Control Strategy of Modular Multilevel Photovoltaic Grid-Connected Inverter

Cited by 4 publications

References 39 publications

Fault Diagnosis and Tolerant Control of Three-Level Neutral-Point Clamped Inverters in Motor Drives

Fault Diagnosis and Tolerant Control of Three-Level Neutral-Point Clamped Inverters in Motor Drives

A Secondary Reconfigurable Inverter and Its Control Strategy

A Fault-Tolerant Control Strategy of Modular Multilevel Converter with Sub-Module Faults Based on Neutral Point Compound Shift

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