scholarly journals Open-Circuit Fault Tolerance Method for Three-Level Hybrid Active Neutral Point Clamped Converters

Electronics ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1535 ◽  
Author(s):  
Laith M. Halabi ◽  
Ibrahim Mohd Alsofyani ◽  
Kyo-Beum Lee
Keyword(s):  
Fault Tolerance ◽  
Fault Tolerant ◽  
Harmonic Distortion ◽  
Industrial Applications ◽  
Open Circuit ◽  
Neutral Point ◽  
Normal Operation ◽  
Recent Developments ◽  
Additional Costs ◽  
Tolerance Method

Three-level converters are the most important technologies used in high power applications. Among these technologies, active neutral point clamped (ANPC) converters are mainly used for industrial applications. Meanwhile, recent developments have reduced losses and increased efficiency by using a hybrid combination of Si-IGBT and SiC-MOSFET switches to achieve hybrid ANPC (HANPC) converters. Open-circuit failure is regarded as a common and serious problem that affects the operational performance. In this paper, an effective fault-tolerant method is proposed for HANPC converters to safely re-utilize normal operation and increase the reliability of the system under fault conditions. Sequentially, regarding different topologies with reference to earlier fault tolerance methods which could not be applied to the HANPC, the proposed strategy enables continuous operation under faulty conditions effectively without using any additional devices by creating new voltage references, voltage offset, and switching sequences under the faulty conditions. Consequently, no additional costs or changes are associated with the inverter. A detailed analysis of the proposed strategy is presented highlighting the effects on the voltage, currents, and the corresponding total harmonic distortion (THD). The simulation and experimental results demonstrate the capability and effectiveness of the proposed method to maintain normal operation and eliminate the output distortion.

Loss Analysis of Three-Level Active Neutral Point Clamped Converter under Fault Tolerance Operation

2012 ◽  
Vol 588-589 ◽  
pp. 847-850
Author(s):  
Wei Jing ◽  
Ran Ding
Keyword(s):  
Fault Tolerance ◽  
Fault Tolerant ◽  
Short Circuit ◽  
Phase Relationship ◽  
Open Circuit ◽  
Neutral Point ◽  
Normal Operation ◽  
Switching Frequency ◽  
Continuous Output ◽  
Control Schemes

Compared with traditional three-level neutral-point-clamped (NPC) converter, the recently proposed three-level active NPC (ANPC) converter has the ability to overcome the unbalanced loss distribution, and therefore result in increased output power or switching frequency. In industrial applications, fault tolerance ability of power converters is very important considering system availability, safety and reliability. This paper introduced the control schemes to get stable and continuous output under single device fault for both open-circuit and short-circuit fault cases. By analyzing the phase relationship of reference voltage and load current, the loss calculation method under fault tolerant operation was proposed. Calculation results show that the devices junction temperatures under fault tolerant operation are within the safe operation area (SOA) even they are a little bit higher compared to normal operation, which also confirm the effectiveness of the fault tolerant control schemes.

Open‐circuit fault diagnosis for a fault‐tolerant three‐level neutral‐point‐clamped STATCOM

2019 ◽  
Vol 12 (4) ◽  
pp. 810-816 ◽  
Author(s):  
Haoyang Li ◽  
Yuanbo Guo ◽  
Jinhui Xia ◽  
Ze Li ◽  
Xiaohua Zhang
Keyword(s):  
Fault Diagnosis ◽  
Fault Tolerant ◽  
Open Circuit ◽  
Neutral Point ◽  
Circuit Fault Diagnosis

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

Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 876 ◽  
Author(s):  
Qinyue Zhu ◽  
Wei Dai ◽  
Lei Guan ◽  
Xitang Tan ◽  
Zhaoyang Li ◽  
...  
Keyword(s):  
Fault Tolerance ◽  
Control Strategy ◽  
Control Method ◽  
Fault Tolerant ◽  
Fault Tolerant Control ◽  
Neutral Point ◽  
Modular Multilevel Converter ◽  
Phase Voltage ◽  
Multilevel Converter ◽  
Shift Control

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.

scholarly journals Open-Circuit Fault-Tolerant Design of the Cascaded H-Bridge Rectifier Incorporating Reactive Power Compensation

Electronics ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1490
Author(s):  
Ting Chen ◽  
Hong Cheng ◽  
Cong Wang ◽  
Wenbo Chen ◽  
Zhihao Zhao
Keyword(s):  
Single Phase ◽  
Reactive Power ◽  
Power Transmission ◽  
Fault Tolerant ◽  
Reactive Power Compensation ◽  
Open Circuit ◽  
Normal Operation ◽  
Bridge Rectifier ◽  
Drive Signals ◽  
Fault Tolerant Design

This paper proposes an open-circuit fault-tolerant design for the cascaded H-Bridge rectifier incorporating reactive power compensation. If one or two switching devices of the H-bridge modules are fault, the drive signals of the faulty H-bridge modules will be artificially redistributed into the bridgeless mode (including the boost bridgeless mode, the symmetric boost bridgeless mode, the totem-pole bridgeless mode and the symmetry totem-pole bridgeless mode) and cooperate with the normally operated H-bridge modules. In this case, the faulty cascaded H-bridge rectifier is not only able to achieve active power transmission, but also can still provide part of reactive power compensation when injecting reactive power from the power grid. Nonetheless, the reactive power that it can supply will be limited, due to the unidirectional characteristics of the bridgeless mode for the faulty modules. Therefore, a method for calculating its adjustable power factor angle range is also presented, which provides the basis for the faulty modules switching to the bridgeless mode. Then, a control strategy of the cascaded H-bridge rectifier incorporating reactive power compensation under the faulty condition and normal operation is presented. Finally, an experimental platform with a single-phase cascaded H-bridge rectifier containing three cells is given to verify the proposed theories.

scholarly journals New Diagnosis and Fault-Tolerant Control Strategy for Photovoltaic System

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Hassan Abouobaida ◽  
Younes Abouelmahjoub
Keyword(s):  
Control Strategy ◽  
Fault Tolerant ◽  
Fault Tolerant Control ◽  
Open Circuit ◽  
Maximum Power ◽  
Photovoltaic System ◽  
Normal Operation ◽  
Switching Frequency ◽  
Point Tracking ◽  
Interleaved Boost Converter

This paper discusses open-circuit fault (OCF) diagnosis and fault-tolerant control strategy (FTCS) of a nonisolated DC-DC converter. The photovoltaic power conversion structure (PPCS) consists of a photovoltaic generator and an interleaved Boost converter (IBC). The maximum power point tracking (MPPT) control of the IBC ensures operation at maximum power. The design of the nonlinear Backstepping control is detailed based on the equivalent average model of IBC, and the stability is studied using Lyapunov’s theorem. The proposed OCF fault detection is based on sampling the voltage across the inductor at a much higher frequency than the switching frequency. In an OCF situation occurrence and a high control signal state, the detection of three negative samples is a condition for signaling the presence of an OCF fault; the photovoltaic system continues its normal operation. The simulation results show the validity of the proposed FTCS. The proposed diagnosis and control strategy improves the performance of the IBC in terms of cost, reliability, and service continuity.

scholarly journals Fault-Tolerant Control Strategy for Neutral-Point-Clamped Three-Level Inverter

2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Yanxia Shen ◽  
Beibei Miao ◽  
Dinghui Wu ◽  
Kader Ali Ibrahim
Keyword(s):  
Control Strategy ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Fault Tolerant ◽  
Fault Tolerant Control ◽  
Open Circuit ◽  
Neutral Point ◽  
Control Technique ◽  
Action Time ◽  
Addition And Subtraction

A fault-tolerant control technique is discussed for the Neutral-Point-Clamped (NPC) three-level inverter, which ensures that the NPC inverter operates normally even under device failures. A two-level leg is added to the NPC inverter; when the device open circuit fault occurs, the load of this faulty phase is connected to the neutral point of this two-level leg through the bidirectional thyristors. An improved Space Vector Pulse Width Modulation (SVPWM) strategy called “addition and subtraction substitution SVPWM” is proposed to effectively suppress fluctuation in capacitor neutral-point voltages by readjusting the sequence and action time of voltage vectors. The fault-tolerant topology in this paper has the advantages of fewer switching devices and lower circuit costs. Experimental results show that the proposed fault-tolerant system can operate in balance of capacitor neutral-point voltages at full output power and the reliability of the inverter is greatly enhanced.

scholarly journals Fault Tolerant Modular Inductive Power Transfer System Design Using Resonator Coil

2021 ◽  
Author(s):  
Hakan Polat
Keyword(s):  
System Design ◽  
Fault Tolerant ◽  
Open Circuit ◽  
Normal Operation ◽  
Transfer System ◽  
Power Transfer ◽  
Inductive Power Transfer ◽  
Wide Range ◽  
Resonator System ◽  
Inductive Power

<div>In this paper, a design for an inductive power transfer system with a series-series topology with an intermediate resonator is discussed. The proposed method is an improved method that is derived from a conventional IPT system design. While it is applicable for a wide range of different operations, a contactless slip ring design is the main system under investigation. The idea behind adding a resonator coil is to achieve fault tolerance where the system can operate under various open-circuited fault conditions. The proposed system is a two transmitter and four receiver with an intermediate resonator system where the Rx modules are connected parallel to a common DC-bus. </div><div>The system is found to be fault-tolerant to Rx side open circuit faults. For normal operation at rated power, 90.6\% efficiency was achieved.</div>

scholarly journals Feasibility Assessment of a Kalman Filter Approach to Fault Detection and Fault-Tolerance in a Highly Unstable System: The RIT Heart Pump

2009 ◽  
Author(s):  
Erin M. Gillespie ◽  
Wayne Walter
Keyword(s):  
Kalman Filter ◽  
Fault Tolerance ◽  
Fault Detection ◽  
Fault Tolerant ◽  
Position Sensor ◽  
Unstable System ◽  
Plant Model ◽  
Heart Pump ◽  
Filter Approach ◽  
Tolerance Method

The purpose of this project is to assess the feasibility of a Kalman Filter approach for fault detection in a highly unstable system, specifically a heart pump that is currently under development at RIT. Simulations and experimental work were completed to determine the effects of possible position sensor fault conditions on the system; that information was then used in conjunction with a pair of Kalman filters to create a method of detecting faults and providing fault-tolerant operation. The estimator system was designed and tested using SIMULINK™. The simulations showed the filters were able to calculate and remove bias caused by any type of position sensor error, provided the estimated plant model is nearly identical to the actual plant model. Sensitivity analysis showed that the fault detection/fault-tolerance method is extremely sensitive to discrepancies between the estimated plant model and actual pump behavior. Consequently, it is considered unfeasible for implementation on a real system. Experimental results confirmed these findings, demonstrating the drawbacks of model-based fault detection and tolerance methods.

scholarly journals Improving the Fault Tolerance of Elements of Modern Infocommunication Networks with the Use of Default Gateway Redundancy Protocols

2020 ◽  
pp. 68-81
Author(s):  
Oleksandra Yeremenko ◽  
Amal Mersni
Keyword(s):  
Fault Tolerance ◽  
Network Architecture ◽  
Fault Tolerant ◽  
Future Research ◽  
Software Defined Network ◽  
Control Plane ◽  
Network Resources ◽  
Data Plane ◽  
Recent Developments ◽  
Control Traffic

The article is devoted to the Network Layer means to ensure resilience during designing an infocommunication system that can counteract faults and failures. A review of the default gateway redundancy protocols concept and analysis of recent developments to overcome fault tolerance challenges in the Software-Defined Networks (SDN) control plane are conducted. In addition, an approach to the use of default gateway redundancy protocols in the existing Software-Defined Network architecture is proposed. Therefore, within the approach, the redundancy of the virtual controller is organized based on the current protocol implemented in traditional IP networks, and the SDN switch interacts with the virtual controller. This mechanism aims to reduce the amount of circulating overhead (control traffic), and the backup controller’s organization increases the control plane’s reliability. Whereas in hybrid and hierarchical SDN networks with border routers, the GLBP mechanism can be applied, which increases the reliability of the controller connected to the data plane. In addition, there are several scenarios where the controller that manages the operation of the SDN data plane may have multiple backup controllers to switch in case of failure, or a controller pool is used to manage each network that makes up the SDN data plane. It also highlights promising future areas for research and development to improve Software-Defined Network resilience, which contributes to the emergence of new solutions. Thus, future research directions are seen in proposing mathematical flow-based models of fault-tolerant interaction of the control plane and the data plane based on redundancy. At the same time, setting the problem in an optimization form with the implementation of load balancing will help to use available network resources effectively.

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