Design of a fault-tolerant system for a multi-motor drive with multiple inverter leg faults

Song, Yujin,Zhao, Jin,Sun, Jiajiang The Korean Institute of Power Electronics 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.11

A novel fault-tolerant system for a multi-motor drive with one-leg, two-leg, and secondary faults is designed in this study. Fault tolerance is realized from pre-fault to post-fault via a topology reconstruction scheme and an integrated control law. The scheme develops a reconstructible topology and its reconstruction algorithm. The multi-motor drive can be reconstructed into appropriate tolerant topologies on the basis of the diagnosis results. The control law based on the predictive torque control method is universal under any topology by designing a unified voltage vector model and an optimal switching state decision. The proposed system can cope with more types of faults and effectively switch from a healthy state to a fault-tolerant state under any fault. The effectiveness and performance of the fault-tolerant system are verified and demonstrated by simulation and experiment results.

Fault tolerance for PWM rectifiers based on basic voltage space vector model

Chao Sun,Yingning Qiu 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.7

A new basic voltage space vector model-based fault tolerance method from new perspective of vector reconstruction for generator side converter open circuit faults is proposed in this paper. In the space vector model, changes of voltage space vectors under single and multiple switch open-circuit fault conditions are summarized in mathematical expressions. The corrected voltage space vectors under fault conditions are essentially linear superpositions of normal voltage space vectors and the changes introduced by their corresponding faulty switches. The new fault tolerance method, which is developed based on a basic voltage vector model, uses reconstructed basic voltage space vectors to compensate the reference voltage vector. It realizes full-scale fault-tolerant compensation. The feasibility and superiority of the proposed fault-tolerant method are tested and compared on an experimental platform. The achieved superior system performance of the proposed fault tolerance method sufficiently demonstrates its effectiveness as well as the voltage vector deviation principle presented in this paper. It provides important insights into the fault tolerance control of power converters.

종방향 자율주행의 미지 고장 재건을 위한 순환 최소 자승 기반 적응형 슬라이딩 모드 관측기 개발

오세찬,송태준,이종민,오광석,이경수 사단법인 한국자동차안전학회 2021 자동차안전학회지 Vol.13 No.1

This paper presents a RLS based adaptive sliding mode observer (A-SMO) for unknown fault reconstruction in longitudinal autonomous driving. Securing the functional safety of autonomous vehicles from unexpected faults of sensors is essential for avoidance of fatal accidents. Because the magnitude and type of the faults cannot be known exactly, the RLS based A-SMO for unknown acceleration fault reconstruction has been designed with relationship function in this study. It is assumed that longitudinal acceleration of preceding vehicle can be obtained by using the V2V (Vehicle to Vehicle) communication. The kinematic model that represents relative relation between subject and preceding vehicles has been used for fault reconstruction. In order to reconstruct fault signal in acceleration, the magnitude of the injection term has been adjusted by adaptation rule designed based on MIT rule. The proposed A-SMO in this study was developed in Matlab/ Simulink environment. Performance evaluation has been conducted using the commercial software (CarMaker) with car-following scenario and evaluation results show that maximum reconstruction error ratios exist within range of ±10%.

슬라이딩 모드 관측 및 제어 기반 자율주행 자동차의 종방향 고장 허용 제어 알고리즘

오광석,이종민,이경수 대한기계학회 2019 大韓機械學會論文集A Vol.43 No.1

This paper describes a sliding mode observer and control-based approach for a longitudinal fault-tolerant control algorithm of autonomous vehicles. To detect faults in a longitudinal acceleration sensor, the relative acceleration is reconstructed using a sliding mode observer. The relative acceleration is then used for probabilistic fault detection. When a fault is detected, the virtual acceleration is derived using the reconstructed value as an input for a lower level controller. In an upper level controller, the desired robust acceleration is derived when considering uncertainties such as the acceleration of the preceding vehicle, virtual acceleration, and the control performance. Actual driving data and a 3D vehicle model are used for a performance evaluation. It is expected that the algorithm can be applied as a fail-safe for autonomous driving. 본 연구는 슬라이딩 모드 관측 및 제어 기반 자율주행 자동차의 종방향 고장 허용 제어 알고리즘에 관한 것이다. 종방향 가속도 센서의 고장 탐지를 위해 슬라이딩 모드 관측기를 이용하여 상대가속도를 재건한다. 재건된 상대가속도 기반 가속도 확률분포를 이용하여 종방향 가속도의 확률적 고장탐지를 수행한다. 고장 탐지 시 재건된 가속도를 이용하여 가상 가속도를 도출하고, 가상 가속도를 허용 제어를 위해 하위 제어기의 가속도 입력으로 사용한다. 상위 제어기의 슬라이딩 모드 제어기는 선행차량 가속도, 가상 가속도, 하위 제어기 제어성능 불확실성에 대해 강건한 요구 가속도를 도출한다. 성능평가를 위해 속도 구간 별 실 주행 데이터와 3차원 차량 동역학 모델을 이용하여 사용하였다. 본 연구에서 제안하는 고장 허용 제어 알고리즘은 향후 자율주행 종방향 고장안전을 위해 적용될 것으로 예상한다.

Robust Actuator Fault Reconstruction for Takagi-Sugeno Fuzzy Systems with Time-varying Delays via a Synthesized Learning and Luenberger Observer

Qingxian Jia,Lina Wu,Huayi Li 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.2

This paper addresses the problem of robust actuator fault reconstruction for Takagi-Sugeno (T-S) fuzzy systems subjects to actuator faults, unknown inputs and time-varying delays via a Fuzzy Synthesized Learning and Luenberger Observer (FSL2O). Through a coordinate transformation, the original T-S fuzzy system is decomposed into two subsystems: subsystem-1 effected by actuator faults and subsystem-2 effected by unknown inputs. In the presented FSL2O methodology, a Reduced-Order Fuzzy Learning Observer (ROFLO) is explored for the subsystem1 to reconstruct actuator faults accurately while a Reduced-Order Fuzzy State (Luenberger) Observer (ROFSO) is designed for the subsystem-2 based on the H∞ control technique such that it has strong robustness against the unknown inputs. The synthesized design of the ROFLO and the ROFSO is formulated in a unified manner in terms of Linear Matrix Inequalities (LMIs) that can be conveniently solved using LMI optimization technique. In addition, as a comparison, a full-order FLO is suggested for robust actuator fault reconstruction. Finally, a numerical exampleand simulation are provided to demonstrate the effectiveness of the proposed approaches.

PCA Fault Isolation Using Interval Reconstruction

Raoudha Bel Hadj Ali,Anissa Ben Aicha,Kamel Belkhiria,Gilles Mourot 제어·로봇·시스템학회 2024 International Journal of Control, Automation, and Vol.22 No.2

Fault detection and isolation (FDI) based on principal component analysis (PCA) has been widely developed. However, PCA is used for FDI without regard to model uncertainties. In this paper, the model uncertainties being represented as interval, we propose to perform multiple fault isolation by extending the reconstruction principle to interval PCA model. Variable reconstructions can be expressed as a problem of solving a system of interval linear equations. From these reconstructions, interval structured residuals are designed in order to identify the set of faulty variables. However, the number and directions of faults being a priori unknown, a multiple fault isolation strategy is proposed in order to alleviate analyzing all combinations related to simultaneous variable reconstructions. Our innovative method is illustrated on a simulation example. The interest of taking into consideration the model uncertainties on FDI will be illustrated.

Robust Composite Observer Based State Estimation and Simultaneous Fault Reconstruction for One-sided Lipschitz Nonlinear Systems

Guanghao Su,Zhenlei Wang 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.10

With the increasing demands on system performance and reliability in engineering practice, fault tolerant control and disturbance rejection control are widely concerned by researchers, in which state and unknown input observation is the fundamental segment. Extended state observer (ESO) and disturbance observer (DO) are two mainstream tools in this field. However, lower triangle system structure is required in ESO design, and the application of DO relies on state measurement. In this paper, a robust composite observer is proposed to estimate states and faults simultaneously for one-sided Lipschitz uncertain nonlinear systems. At first, fault signal is split to matched and mismatched parts. Secondly, extended nonlinear unknown input observer (ENUIO) is designed to estimate system states and mismatched faults. Based on above estimated information, nonlinear disturbance observer (NDO) is utilized to reconstruct the matched faults. Then, synthesis condition derivation and rigorous stability analysis are conducted with the help of one-sided Lipschitz and quadratically inner-bounded conditions. Finally, two numerical examples are given to illustrate the validity and effectiveness of the proposed method.

New Results in Disturbance Decoupled Fault Reconstruction in Linear Uncertain Systems Using Two Sliding Mode Observers in Cascade

Chee Pin Tan,Kok Yew Ng,Zhihong Man,Rini Akmeliawati 제어·로봇·시스템학회 2010 International Journal of Control, Automation, and Vol.8 No.3

This paper presents a disturbance decoupled fault reconstruction (DDFR) scheme using two sliding mode observers in cascade. Measurable signals from the first observer are found to be the output of a fictitious system that is driven by the fault and disturbances. Then the signals are fed into a second observer which will reconstruct the fault. Sufficient conditions which guarantee DDFR are investigated and presented in terms of the original system matrices, and they are found to be less conservative than if only one single observer is used; therefore DDFR can be achieved for a wider class of systems using two sliding mode observers. A simulation example validates the claims made in this paper.

Faulty Sensor Detection, Identification and Reconstruction of Indoor Air Quality Measurements in a Subway Station

Hongbin Liu,Mingzhi Huang,Iman Janghorban,Payam Ghorbannezhad,ChangKyoo Yoo 제어로봇시스템학회 2011 제어로봇시스템학회 국제학술대회 논문집 Vol.2011 No.10

Indoor air quality (IAQ) is important in subway stations because it can influence the health and comfort of passengers significantly. To effectively monitor and control the IAQ in subway stations, several key air pollutants data were collected by the air sampler and tele-monitoring system. In this study, an air pollutant prediction model based an adaptive network-based fuzzy inference system (ANFIS) was used to detect sensor fault, and a structured residual approach with maximum sensitivity (SRAMS) method was used to identify and reconstruct sensor faults existing in subway system. When a sensor failure was detected, the faulty sensor was identified using the exponential weighted moving average filtered squared residual (FSR). Four identification indices, including the identification index based on FSR (IFSR), the identification index based on generalized likelihood ratio (IGLR), the identification index based on cumulative sum of residuals (IQsum), and the identification index based on cumulative variances index (IVsum) were used to assist in identifying sensor faults. The best reconstructed sensor value can be estimated based on a given sensor fault direction. The drifting sensor failure was tested and the effectiveness of the proposed sensor validation procedure was verified.

Robust Observer-based Sensor Fault Reconstruction for Discrete-time Systems via a Descriptor System Approach

Qingxian Jia,Huayi Li,Yingchun Zhang,Xueqin Chen 제어·로봇·시스템학회 2015 International Journal of Control, Automation, and Vol.13 No.2

This paper addresses the problem of observer-based sensor fault reconstruction for discrete-time systems subject to external disturbances via a descriptor system approach. First, an augmented descriptor system is formulated by letting the sensor fault term be an auxiliary state vector; then a discrete-time descriptor state observer is constructed to achieve concurrent reconstructions of original system states and sensor faults. Sufficient and necessary conditions for the asymptotic stability of the proposed observer are explicitly provided. To broaden its application scope, less restrictive existence conditions are further discussed. Further, sufficient conditions for the robust stability of the proposed observer are formulated in terms of linear matrix inequalities (LMIs) that can be conveniently solved using LMI optimization techniques. After that, an extension of the proposed linear approach to discrete-time nonlinear systems with Lipschitz constraint is investigated. At last, two illustrative examples are given to verify the effectiveness of the proposed techniques.