Fault-tolerant Operation Research Articles

Steel-ball-type six-dimensional dynamic force measurement platform with fault-tolerant performance

To satisfy the requirement of dynamic vibration testing of aerospace equipment on the ground prior to orbiting in space to guarantee the stable functioning of precision components, a steel-ball-type dynamic force measuring platform is suggested. First, based on two traditional platforms, a novel dynamic force measuring platform with fault-tolerant function, higher load capacity, and higher fundamental frequency is proposed, with its fault-tolerant measurement method theoretically deduced. Next, the study focuses on improving the measuring performance of redundant platforms by transforming conventional hard-connected branches into steel-ball branches. The structural parameters of these branches are examined theoretically, and simulations are used to confirm the theory's accuracy. Ultimately, the prototypes of the redundant steel-ball and hard-connected platforms are fabricated. Comparative experiments demonstrate that the steel-ball platform has superior performance, with static and dynamic measuring errors of 1.2% and 2.3%, respectively, and static and dynamic average coupling errors of 0.3% and 1.5%, respectively. The fault-tolerance function's validity is also confirmed.

Temperature field analysis and equal-amplitude temperature rise constraint current control method under open-circuit fault-tolerant operation for five-phase permanent magnet motor

The phase redundancy and freedom of the five-phase permanent magnet motor (FPPMM) enhance the reliability of the motor system. However, the temperature rise and torque reduction issues of the motor during open-circuit fault operation need to be further studied. In order to study the temperature distribution characteristics and the output capability of the motor under fault operation subject to temperature rise constraints, a 3-D global temperature field model containing a complex heat dissipation structure has been established. And the equal-amplitude temperature rise constraint current control method is proposed under open-circuit fault-tolerant operation to improve its output capability. The temperature distribution of the motor during steady state operation under rated operating conditions is analyzed with emphasis. Based on this, the temperature field changes of the motor during single-phase and two-phase open-circuit fault-tolerant operation are investigated. Then, the proposed equal-amplitude temperature rise constrained current method is introduced in detail to ensure the safe operation of the motor. An experimental platform is built, which verifies the accuracy of the temperature field calculation, as well as the correctness of equal-amplitude temperature rise constrained current method.

High-fidelity spin qubit operation and algorithmic initialization above 1 K

The encoding of qubits in semiconductor spin carriers has been recognized as a promising approach to a commercial quantum computer that can be lithographically produced and integrated at scale1–10. However, the operation of the large number of qubits required for advantageous quantum applications11–13 will produce a thermal load exceeding the available cooling power of cryostats at millikelvin temperatures. As the scale-up accelerates, it becomes imperative to establish fault-tolerant operation above 1 K, at which the cooling power is orders of magnitude higher14–18. Here we tune up and operate spin qubits in silicon above 1 K, with fidelities in the range required for fault-tolerant operations at these temperatures19–21. We design an algorithmic initialization protocol to prepare a pure two-qubit state even when the thermal energy is substantially above the qubit energies and incorporate radiofrequency readout to achieve fidelities up to 99.34% for both readout and initialization. We also demonstrate single-qubit Clifford gate fidelities up to 99.85% and a two-qubit gate fidelity of 98.92%. These advances overcome the fundamental limitation that the thermal energy must be well below the qubit energies for the high-fidelity operation to be possible, surmounting a main obstacle in the pathway to scalable and fault-tolerant quantum computation.

Experimental Assessment of Predictive Current Control Applied to Induction Machine Drive Systems Operating Under Single-Phase Open-Circuit Fault


 Predictive Current Control (PCC) has been widely applied in several applications. However, the literature has not discussed its use as a fault tolerance control algorithm in induction drive systems. In this way, this paper discusses the PCC method in two faulttolerant squirrel-cage induction machine drive systems operating under single-phase open-circuit faults. PCC’s postfault performance is compared to Field Oriented Control (FOC) for different steady- and transient-state scenarios, analyzing harmonic distortion, torque ripple, and the transition from healthy to postfault operation. Also, experiments tested the robustness of postfault PCC to low-speed operation, parametric variation, and a step change in reference rotor speed, showing that PCC also presents fault-tolerant operation under these conditions.

Simultaneous fault-tolerant control and disturbance rejection for impulsive switched systems

This paper considers the simultaneous fault-tolerant control and disturbance rejection of impulsive switched linear systems. First, estimates of faults and disturbances in the system can be obtained by designing observers. Then, through the obtained estimation, the controller with anti-interference performance and fault tolerance performance is designed. Under the arbitrary switching rules and the minimum dwell time switching rules, the stability of the system is guaranteed. Finally, the effectiveness of the method is verified by numerical simulation and example simulation.

Modulation Techniques and Coordinated Voltage Vector Distribution: Effects on Efficiency in Dual-Inverter Topology-Based Electric Drives

The increasing popularity of electric drives employing an isolated dual-inverter (DI) topology is motivated by their superior DC-link voltage and power utilization, fault-tolerant operation, and potential for multilevel operation. These attributes are significant in battery-powered transportation, such as electric vehicles and aviation. Given the considerable freedom in modulation and control of the DI topology, this paper researches the impact of reference voltage vector distribution between the two individual inverters. The study also evaluates the influence of two well-established asynchronous modulation strategies—Space Vector PWM (SVPWM) and Depenbrock’s Discontinuous Modulation (DPWM1). Since simulation tools nowadays play a crucial role in power electronics design and concept verification, the results are based on extensive and detailed models in Matlab/Simulink. Employing the basic field-oriented control of a 12 kW induction motor with precisely parameterized SiC switching devices for accurate loss calculation, this research reveals the possibility of significant energy savings at multiple operating points. Notably, optimal efficiency is achieved when one inverter operates up to half of the nominal speed while the other solely establishes a neutral point for the winding. Moreover, the results highlight DPWM1 as a superior strategy for the DI topology, showcasing reduced converter losses. Overall, it is shown that the system’s losses can be significantly reduced just by the design of the voltage vector distribution in the drive’s operating range and the modulation strategy selection.

UETOPSIS: A Data-Driven Intelligence Approach to Security Decisions for Edge Computing in Smart Cities

Despite considerable technological advances for smart cities, they still face problems such as instability of cloud server connection, insecurity during data transmission, and slight deficiencies in TCP/IP network architecture. To address such issues, we propose a data-driven intelligence approach to security decisions under Named Data Networking (NDN) architecture for edge computing, taking into consideration factors that impact device entry in smart cities, such as device performance, load, Bluetooth signal strength, and scan frequency. Despite existing techniques for Order Preference by Similarity to Ideal Solution (TOPSIS)-based on entropy weights methods are improved and applied, there exist unstable decision results. Due to this, we propose a technique for Order Preference by Similarity to Ideal Solution (TOPSIS)-based on utility function and entropy weights, named UETOPSIS, where the corresponding utility function is applied according to the influence of each attribute on the decision, ensuring the stability of the ranking of decision results. We rely on an entropy-based weights mechanism to select a suitable master controller for the design of the multi-control protocol in the smart city system, and utilize a utility function to calculate the attribute values and then combine the normalized attribute values of utility numbers, starting by analyzing the main work of the controllers. Lastly, a prototype is developed for performance evaluation purposes. Experimental evaluation and analysis show that the proposed work has better authenticity and reliability than existing works and can reduce the workload of edge computing devices when forwarding data, with stability 24.7% higher than TOPSIS, significantly improving the performance and stability of system fault tolerance and reliability in smart cities, as the second-ranked controller can efficiently take over the work when a central controller fails or damaged.

Research on Optimization Method for Fault-Tolerant Integration of Real-Time Dual-Computer Embedded Systems

Abstract This paper addresses the fault-tolerant performance of real-time dual-computer embedded systems. The article first emphasizes the importance of real-time and reliability in various fields and points out that improving fault-tolerant performance is a crucial topic. Based on the Markov chain algorithm, the study optimizes the fault-tolerant integration method for real-time dual-computer embedded systems. By constructing a model of Markov algorithm and using the deadline of the task as a benchmark, the passage and transfer probabilities of faults are calculated. The article also provides algorithmic proofs of fault-tolerant control of Markovian jump systems and calculates their stability levels. The results show that the fault passage rate of the system increases as the number of complex tasks increases, e.g., when the number of complex tasks is 4, the passage rate can reach 90%. In addition, in the scheduling test, it was found that the schedulability of the system increases with the increase in the number of processors. When the number of processors reaches 5, the system's schedulability is 43%. In conclusion, the system fault tolerance optimization method based on Markov algorithm proposed in the article can effectively improve the reliability and fault tolerance of the system.

Fault–tolerant Operation of Switched Reluctance Motor Using Cascaded Current and PWM Control With Effect of Commutation Angle Variation

Fault–tolerant Operation of Switched Reluctance Motor Using Cascaded Current and PWM Control With Effect of Commutation Angle Variation

An Outer Rotor Surface PM Motor with Integrated Chokes for Fault-Tolerant Operation in the Presence of Short-Circuit Faults between Adjacent Turns

An Outer Rotor Surface PM Motor with Integrated Chokes for Fault-Tolerant Operation in the Presence of Short-Circuit Faults between Adjacent Turns

Fault-Tolerant Operation for Single-Phase Open Circuit of Dual-Armature Flux-Switching Permanent Magnet Machine by Connecting Neutral Points

Fault-Tolerant Operation for Single-Phase Open Circuit of Dual-Armature Flux-Switching Permanent Magnet Machine by Connecting Neutral Points

Dual Motor Power Sharing Control for Electric Vehicles With Battery Power Management

Induction motor powertrains are emerging as a cost-effective option for high-power electric vehicles (EVs). A differential four-wheel drive (D4WD) EV based on two open end winding induction motor (OEWIM) propulsion is presented in this paper. Each OEWIM is driven by two 2-level voltage source inverters (VSI) with two isolated battery packs as the source. The proposed drive control algorithm integrates the uniform state-of-charge (SoC) distribution and fault-tolerant operation. A two-stage look-up table (LUT) based direct torque control (DTC) scheme is proposed to balance the SoC of batteries by selecting the suitable redundant VSI voltage vectors. The proposed LUT-DTC scheme is less sensitive to variations in motor parameters and provides excellent steady-state and transient performance. The results show the superiority of the proposed controller in terms of battery SoC balancing. The performance of the EV drive with the proposed LUT-DTC is validated by both simulation and laboratory experiments for the FTP75 and HFET driving cycles under different operating modes under normal and fault conditions. The dual motor driven D4WD with the proposed LUT-DTC is found to achieve 89.2% efficiency.

A randomized benchmarking suite for mid-circuit measurements

Mid-circuit measurements are a key component in many quantum information computing protocols, including quantum error correction, fault-tolerant logical operations, and measurement based quantum computing. As such, techniques to quickly and efficiently characterize or benchmark their performance are of great interest. Beyond the measured qubit, it is also relevant to determine what, if any, impact mid-circuit measurement has on adjacent, unmeasured, spectator qubits. Here, we present a mid-circuit measurement benchmarking suite developed from the ubiquitous paradigm of randomized benchmarking. We show how our benchmarking suite can be used to both detect as well as quantify errors on both measured and spectator qubits, including measurement-induced errors on spectator qubits and entangling errors between measured and spectator qubits. We demonstrate the scalability of our suite by simultaneously characterizing mid-circuit measurement on multiple qubits from an IBM Quantum Falcon device, and support our experimental results with numerical simulations. Further, using a mid-circuit measurement tomography protocol we establish the nature of the errors identified by our benchmarking suite.

A Novel Fault Tolerance Structure of Arc Linear Flux Switching Permanent Magnet Motors Based on Redundant Winding

This paper presents a novel structure of the arc linear flux switching permanent magnet motor based on the redundant winding to inhibit the rises of the motor losses and temperature due to the open circuit fault tolerance. Firstly, the structural characteristic of the arc linear flux switching permanent magnet motor is introduced. Then, the fault tolerance current of single phase open circuit fault is calculated for different winding connection forms. The fault tolerance performances under different conditions are compared from a special view of motor temperature rises. Finally, a novel structure for fault tolerance enhancement is proposed, which can effectively improve the freedom degree of the fault tolerance current by using the redundant winding. This novel structure takes full advantage of the circumferential air gap between the arc stator. The calculation results show that the novel structure can allow the fault tolerance of open circuit fault has little influence on the motor copper losses and temperature rises while maintaining the on-load torque.

Design and Analysis of a Novel Six-Phase Axial Switched-Flux Permanent Magnet Machine With Different Winding Configuration

In this paper, a novel six-phase axial switched-flux permanent magnet (PM) machine with stator-PM is proposed and designed. The topology and operating principle are analyzed in detail. Two different winding configurations, which are called the symmetric double-three-phase and asymmetric double-three-phase, are presented and studied. The electromagnetic performance of the machine with two winding configurations, including flux-linkage, back electromotive force, inductance, torque characteristics, and so on, is investigated. The behavior of the machine under the healthy and faulty conditions is analyzed and the fault-tolerant performance is researched. The prototype is manufactured and the experimental results are consistent with that of the finite element analysis. The results demonstrate that the performance of the machine with two winding configurations is excellent. The machine with asymmetric double-three-phase winding configuration has high quality PM flux-linkage and back-EMF, low cogging torque and torque ripple, and strong fault-tolerant capability. The machine with symmetric double-three-phase winding configuration has large torque capacity.

Investigation of Fault-Tolerant Performance and Inductance in a Modular Permanent Magnet In-Wheel Motor

Investigation of Fault-Tolerant Performance and Inductance in a Modular Permanent Magnet In-Wheel Motor

Cooperative Positioning Method of a Multi-UAV Based on an Adaptive Fault-Tolerant Federated Filter.

Aiming at the problem of the low cooperative positioning accuracy and robustness of multi-UAV formation, a cooperative positioning method of a multi-UAV based on an adaptive fault-tolerant federated filter is proposed. Combined with the position of the follower UAV and leader UAV, and the relative range between them, a cooperative positioning model of the follower UAV is established. On this basis, an adaptive fault-tolerant federated filter is designed. Fault detection and isolation technology are added to improve the positioning accuracy of the follower UAV and the fault tolerance performance of the filter. Meanwhile, the measurement noise matrix is adjusted by the adaptive information allocation coefficient to reduce the impact of undetected fault information on the sub-filter and global estimation accuracy. The simulation results show that the adaptive fault-tolerant federated algorithm can greatly improve the positioning accuracy, which is 83.4% higher than that of the absolute positioning accuracy of a single UAV. In the case of a gradual fault, the method has a stronger fault-tolerant performance and reconstruction performance.

A seven level fault tolerant hybrid cascaded inverter for renewable energy applications

Abstract The cascaded H-bridge (CHB) inverters are the prominent inverters used for renewable energy applications. Fault-tolerant operation is one of the foremost concerns to safeguard the continuous operation of the system under a fault on semiconductor switches and DC power supplies. A novel hybrid CHB inverter is proposed by adding a seven-level boost SLB module in cascade with the H-bridge modules. The proposed topology ensures the reliable and dynamic operation of the inverter during the occurrence of a fault. In addition to the fault-tolerant capability of the SLB inverter, the proposed design provides the voltage boosting and self-balancing of the switched capacitors. Extensive simulation results at different operating conditions substantiate the concept of the proposed novel fault-tolerant inverter structure. The prototype system is developed in the laboratory and the experimental results validate the proposed system configuration.

An open circuit fault-tolerant seven-level inverter with symmetric sources and reduced switch count

In this study, a new structure of symmetrical multilevel inverter is proposed. The proposed structure offers fewer controlled switches, power diodes, DC sources voltage stress across switches and losses compared with classical and a few recently proposed topologies in the literature. This paper presents a fault-tolerant (FT) seven-level inverter to provide uninterrupted supply to the connected load under open circuit fault in any single switch of the presented configuration. This configuration uses only six unidirectional and one bidirectional switch for any switch fault-tolerant operation. The phase opposition disposition sinusoidal pulse width modulation (POD-SPWM) and phase disposition sinusoidal pulse-width modulation (PD-SPWM) scheme are used for proper DC link utilisation in seven-level output voltage. The proposed symmetrical 7-level topology requires fewer power components and offers reduced voltage total harmonic distortion (THD) compared to other multi-level inverter (MLI) topologies. This MLI is investigated in MATLAB and validated using hardware in the loop platform of OPAL-RT. The obtained results are presented to demonstrate the successful FT operation under any single switch open circuit fault.

Quantum annealing algorithm for fault section location in distribution networks

As the last link of the power system, the distribution network is responsible for ensuring stable power consumption and improving power quality. Therefore, a more reliable and fast fault section location(FSL) method is essential for the stable operation and optimization of distribution networks. In this context, this paper adopts an effective method to apply the quantum annealing algorithm(QA) based on the quantum tunneling mechanism to the distribution network fault section location problem. A quantum Hamiltonian function consisting of potential and kinetic energy terms is constructed based on the theoretical knowledge of QA. Among them, FSL objective function is mapped to the potential energy term, and the transverse magnetic field is introduced to construct the kinetic energy term, which can realize the quantum tunneling effect and approximate or even reach the global optimal solution. Based on the quantum Hamiltonian function construction, this paper modifies some parameters in the QA framework to propose an improved quantum annealing algorithm(IQA) to improve the accuracy. In the two test systems of IEEE 33-node distribution network and IEEE 33-node distribution network with distributed generation sources(DGs), QA and IQA are compared and analyzed with other intelligent algorithms using the average number of iterations and localization accuracy as indicators. We find that QA is more likely to obtain the global optimal solution compared with the simulated annealing algorithm(SA). IQA can search for faulty sections with 100% accuracy and the least number of average iterations in both single power distribution networks and distribution networks containing DGs. Under the scenarios of fault signal distortion and increasing fault sections, IQA shows superb competitive advantages by exhibiting good fault tolerance performance, global optimal search capability and stability.