scholarly journals Fast Reliability Assessment of Neutral-Point-Clamped Topologies through Markov Models

2020 ◽  
Author(s):  
Sergio Busquets-Monge ◽  
Roya Rafiezadeh ◽  
Salvador Alepuz ◽  
Alber Filba-Martinez ◽  
Joan Nicolas-Apruzzese
Keyword(s):  
Fault Tolerance ◽  
Markov Models ◽  
Reliability Assessment ◽  
Open Circuit ◽  
Neutral Point ◽  
Time To Failure ◽  
Fast Calculation ◽  
Reliability Models ◽  
Minimum Number ◽  
Mean Time

This paper presents detailed Markov models for the reliability assessment of multilevel neutral-point-clamped (NPC) converter leg topologies, incorporating their inherent fault-tolerance under open-circuit switch faults. The Markov models are generated and discussed in detail for the three-level and four-level active NPC (ANPC) cases, while the presented methodology can be applied to easily generate the models for higher number of levels and for other topology variants. In addition, this paper also proposes an extremely fast calculation method to obtain the precise value of the system mean time to failure from any given formulated system Markov model. This method is then applied to quantitatively compare the reliability of two-level, three-level, and four-level ANPC legs under switch open-circuit-guaranteed faults and varying degrees of device paralleling. The comparison reveals that multilevel ANPC leg topologies inherently present a potential for a higher reliability than the conventional two-level leg, questioning the suitability of the traditional search for topologies with the minimum number of devices in order to improve reliability. Experimental results are presented to validate the fault-tolerance assumptions upon which the presented reliability models for the three-level and four-level ANPC legs are based.

scholarly journals Fast Reliability Assessment of Neutral-Point-Clamped Topologies through Markov Models

2020 ◽  
Author(s):  
Sergio Busquets-Monge ◽  
Roya Rafiezadeh ◽  
Salvador Alepuz ◽  
Alber Filba-Martinez ◽  
Joan Nicolas-Apruzzese
Keyword(s):  
Fault Tolerance ◽  
Markov Models ◽  
Reliability Assessment ◽  
Open Circuit ◽  
Neutral Point ◽  
Time To Failure ◽  
Fast Calculation ◽  
Reliability Models ◽  
Minimum Number ◽  
Mean Time

This paper presents detailed Markov models for the reliability assessment of multilevel neutral-point-clamped (NPC) converter leg topologies, incorporating their inherent fault-tolerance under open-circuit switch faults. The Markov models are generated and discussed in detail for the three-level and four-level active NPC (ANPC) cases, while the presented methodology can be applied to easily generate the models for higher number of levels and for other topology variants. In addition, this paper also proposes an extremely fast calculation method to obtain the precise value of the system mean time to failure from any given formulated system Markov model. This method is then applied to quantitatively compare the reliability of two-level, three-level, and four-level ANPC legs under switch open-circuit-guaranteed faults and varying degrees of device paralleling. The comparison reveals that multilevel ANPC leg topologies inherently present a potential for a higher reliability than the conventional two-level leg, questioning the suitability of the traditional search for topologies with the minimum number of devices in order to improve reliability. Experimental results are presented to validate the fault-tolerance assumptions upon which the presented reliability models for the three-level and four-level ANPC legs are based.

scholarly journals Fast Reliability Assessment of Neutral-Point-Clamped Topologies through Markov Models

2020 ◽  
Author(s):  
Sergio Busquets-Monge ◽  
Roya Rafiezadeh ◽  
Salvador Alepuz ◽  
Alber Filba-Martinez ◽  
Joan Nicolas-Apruzzese
Keyword(s):  
Fault Tolerance ◽  
Markov Models ◽  
Reliability Assessment ◽  
Open Circuit ◽  
Neutral Point ◽  
Time To Failure ◽  
Fast Calculation ◽  
Reliability Models ◽  
Minimum Number ◽  
Mean Time

This paper presents detailed Markov models for the reliability assessment of multilevel neutral-point-clamped (NPC) converter leg topologies, incorporating their inherent fault-tolerance under open-circuit switch faults. The Markov models are generated and discussed in detail for the three-level and four-level active NPC (ANPC) cases, while the presented methodology can be applied to easily generate the models for higher number of levels and for other topology variants. In addition, this paper also proposes an extremely fast calculation method to obtain the precise value of the system mean time to failure from any given formulated system Markov model. This method is then applied to quantitatively compare the reliability of two-level, three-level, and four-level ANPC legs under switch open-circuit-guaranteed faults and varying degrees of device paralleling. The comparison reveals that multilevel ANPC leg topologies inherently present a potential for a higher reliability than the conventional two-level leg, questioning the suitability of the traditional search for topologies with the minimum number of devices in order to improve reliability. Experimental results are presented to validate the fault-tolerance assumptions upon which the presented reliability models for the three-level and four-level ANPC legs are based.

Reliability Models to Estimate Mean Time to Failure of Switched Reluctance Machines

2021 ◽  
Author(s):  
Lavanya Vadamodala ◽  
Abdul Wahab Bandarkar ◽  
Shuvajit Das ◽  
Md Ehsanul Haque ◽  
Anik Chowdhury ◽  
...  
Keyword(s):  
Time To Failure ◽  
Mean Time To Failure ◽  
Switched Reluctance ◽  
Reliability Models ◽  
Switched Reluctance Machines ◽  
Mean Time

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.

scholarly journals Fast Reliability Assessment of Neutral-Point-Clamped Topologies through Markov Models

2021 ◽  
pp. 1-1
Author(s):  
Sergio Busquets-Monge ◽  
Roya Rafiezadeh ◽  
Salvador Alepuz ◽  
Alber Filba-Martinez ◽  
Joan Nicolas-Apruzzese
Keyword(s):  
Markov Models ◽  
Reliability Assessment ◽  
Neutral Point

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.

Traction Substation Electrical Main Connection Reliability Analysis

2012 ◽  
Vol 433-440 ◽  
pp. 7293-7299 ◽  
Author(s):  
Xue Cheng Ding ◽  
Zheng You He ◽  
Min Yu
Keyword(s):  
Comparative Analysis ◽  
Reliability Analysis ◽  
Transportation Safety ◽  
Time To Failure ◽  
Reliability Model ◽  
Railway Transportation ◽  
Reliability Models ◽  
Vital Importance ◽  
Traction Substation ◽  
Mean Time

Traction substation reliability is of vital importance for railway transportation safety. To illustrate traction substation reliability, irreparable and reparable reliability models of three types of traction substation Electrical main connection have been established. Based on analysis of simple series and parallel reliability system, system irreparable reliability model is analyzed. The ways of how to get mean time to failure (MTTF) and mean time to first failure (MTTFF) of reparable system are achieved. By comparative analysis of the value of MTTF and MTTFF among three kinds of traction substation main connection reparable and irreparable system, some useful conclusions are found.

scholarly journals The Optimal System for Complex Series-Parallel Systems with Cold Standby Units: A Comparative Analysis Approach

2021 ◽  
Author(s):  
Ibrahim Yusuf ◽  
Ismail Muhammad Musa
Keyword(s):  
Parallel Systems ◽  
Optimal Configuration ◽  
Profit Function ◽  
Time To Failure ◽  
Mean Time To Failure ◽  
Reliability Models ◽  
System Parameters ◽  
Cost Benefits ◽  
Cold Standby ◽  
Mean Time

The purpose of this research is to propose three reliability models (configurations) with standby units and to study the optimum configuration between configurations analytically and numerically. The chapter considered the need for 60 MW generators in three different configurations. Configuration 1 has four 15 MW primary units, two 15 MW cold standby units and one 30 MW cold standby unit; Configuration 2 has three 20 MW primary units, three 20 cold standby units; Configuration 3 has two 30 MW primary units and three 30 MW cold standby units. Some reliability features of series–parallel systems under minor and complete failure were studied and contrasted by the current. Failure and repair time of all units is assumed to be exponentially distributed. Explanatory expressions for system characteristics such as system availability, mean time to failure (MTTF), profit function and cost benefits for all configurations have been obtained and validated by performing numerical experiments. Analysis of the effect of different system parameters on the function of profit and availability has been carried out. Analytical comparisons presented in terms of availability, mean time to failure, profit function and cost benefits have shown that configuration 3 is the optimal configuration. This is supported by numerical examples in contrast to some studies where the optimal configuration of the system is not uniform as it depends on some system parameters. Graphs and sensitivity analysis presented reveal the analytical results and accomplish that Configuration 3 is the optimal in terms of design, reliability physiognomies such as availability of the system, mean time to failure, profit and cost benefit. The study is beneficial to engineers, system designers, reliability personnel, maintenance managers, etc.

scholarly journals Fuzzy-Logic-Based Mean Time to Failure (MTTF) Analysis of Interleaved Dc-Dc Converters Equipped with Redundant-Switch Configuration

2018 ◽  
Vol 9 (1) ◽  
pp. 88 ◽  
Author(s):  
Tohid Rahimi ◽  
Hossein Jahan ◽  
Frede Blaabjerg ◽  
Amir Bahman ◽  
Seyed Hosseini
Keyword(s):  
Fuzzy Logic ◽  
Markov Models ◽  
Reliability Function ◽  
Time To Failure ◽  
Failure Rates ◽  
Mean Time To Failure ◽  
Passive Components ◽  
Multi Phase ◽  
First Time ◽  
Mean Time

Interleaved dc-dc converters in sensitive applications necessitate an enhanced reliability. An interleaved converter equipped with redundant components can fulfill the reliability requirements. Mean Time to Failure (MTTF), as a reliability index, can be used to evaluate the expected life span of the mentioned converters. The Markov model is a helpful tool to calculate the MTTF in such systems. Different scientific reports denote different failure rates with different weight for power elements. Also, in reliability reports, failure rates of active and passive components are uncertain values. In order to approximate the failure rates fuzzy-logic-based Markov models are proposed in this paper. Then it is used to evaluate the MTTF of an interleaved multi-phase dc-dc converter, which is equipped with parallel and standby switch configurations. For the first time, fuzzy curves for MTTFs of the converters and 3D reliability function are derived in this paper. The reliability analyses give an insight to find the appropriate redundant-switch configurations for interleaved dc-dc converters under different conditions. Simulation and experimental results are provided to lend credence to the viability of the studied redundant-switch configurations in interleaved dc-dc boost converter.

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