Joseph J. Yamé

A Novel Approach to Real-Time Fault Accommodation in NREL's 5-MW Wind Turbine Systems

This paper presents a real-time mechanism to tolerate faults occurring in a wind turbine (WT) system. This system is a FAST coded simulator designed by the U.S. National Renewable Energy Laboratorys (NRELs) National Wind Turbine Center. The demonstrated mechanism lies under the taxonomy of active fault-tolerant control (AFTC) systems, namely the projection-based approach. In the proposed approach, we do not use any a priori information about the model of the turbine in real-time. In fact, we use the online measurements generated by WT. Based on the given control objectives, and the observed measurements, an occurring fault is accommodated by reconfiguring the controller such that the turbine generates the rated power even under faulty conditions. Second, no use of an explicit fault-diagnosis module is seen in this approach. Therefore, the fault accommodation delay in the proposed AFTC structure is smaller than the delay as experienced in the traditional structure of AFTC systems.

Synergy of canonical control and unfalsified control concept to achieve fault tolerance

Abstract behavioral theoretical explanation of active fault tolerant control (FTC) problem is proposed in this note. Precisely, we present the concept of canonical controller and unfalsified control in behavioral context. The synergy of two control concepts re-configures the controller such that the system is tolerant to unknown faults. The main feature of the resulting FTC system is that it does not utilize any model-based fault detection and isolation procedure on-line. Therefore, it relies solely on the time-valued trajectories generated by the unknown plant in the closed-loop environment. In our approach to FTC, these trajectories formulate the control specifications that characterize certain desired behavior. Consequently, the controller re-designing process commence when this desired behavior is not satisfied.

Fault-adaptive control of VAV damper stuck in a multizone building

This paper presents a potential effective approach to fault adaptive control for damper stucks in variable-air-volume (VAV) boxes in building heating, ventilation and air-conditioning systems. The fault-adaptive controller integrates a dedicated bank of unknown input residual generators for fault detection/isolation followed by suitably designed fault estimators and a model predictive controller. The adaptation of the controller to the fault is achieved by online modification of the constraints in the model predictive control to achieve reduced energy consumption and thermal comfort under faulty modes. The proposed fault-adaptive control law is demonstrated on a four-zones building benchmark.

Active Fault-Tolerant Control: Current and Past

This chapter reviews the current and past status of the progress made in the area of FTC research. Most of the FTC techniques depends on the type of fault occurred into the system, where the FD plays a significant role. So, the chapter starts with classifying the types of faults followed by the discussion on fault diagnosis and the analysis of various FTC schemes.

Real-Time Smooth Interconnection

The prime aim of a fault-tolerant control system is to maintain the system performance, defined in terms of the desired behavior, at anytime, i.e., even after an occurrence of a fault. In previous two chapters, we presented novel real-time controller reconfiguration mechanisms to deal with the aforementioned issue.

Projection Based Approach to Fault-Tolerant Control

In this chapter, we shall present the solution to the problem of Fault-tolerant Control (FTC) by taking the behavioral system theoretic viewpoint.

Online Redesign Approach to Fault Tolerant Control

In the previous chapter, we presented a novel projection-based approach to solve the active fault-tolerant control problem posed in the Chap. 1.

Design of fault isolation filter for control reconfiguration: Application to energy efficiency control in buildings

In this paper, fault adaptive control is developed for building Heating Ventilation and Air Conditioning (HVAC) systems. That is, the control system parameters and objective functions are adapted/reconfigured in the presence of a fault or performance deviation by means of an intermediate reconfigurable control layer. It allows maintaining building and HVAC operation within its specified energy and comfort performance requirements when a mechanical or operational fault takes place, until the fault is corrected. An integrated design, composed of two levels, respectively fault diagnosis and reconfiguration mechanism is proposed to recover performances after fault occurrence. This approach is applied to a 3 zones building and simulation results are given to show its effectiveness.

Trajectory-based fault accommodation in winder turbine systems

This paper presents a trajectory-based online controller reconfiguration mechanism to tolerate faults in a wind turbine (WT) system. The system is a benchmark WT model which includes FAST coded simulator designed by the U.S. National Renewable Energy Laboratorys. The novelty of the proposed mechanism is that no a priori information about the model of the turbine is used in real-time. Instead, we use online measurements generated by the WT, which in fact captures the behaviour of the wind turbine. Based on the given control specifications, and the observed measurements an occurring fault is accommodated by reconfiguring the controller such that the WT generates the rated power even under faulty conditions.

Modification of an adaptive observer to improve its performance in actuator fault detection

In this paper, we address the problem of actuator fault estimation for continuous linear time-invariant system in the presence of external disturbances. Based on an adaptive observer, the Robust Adaptive Fast Fault Estimation observer (RAFFE) is designed to enhance speed actuator estimation. The construction of the proposed observer is carried out through transformation of system into its Special Coordinate Basis (SCB) form. This transformation allows, in first stage, a decoupling of the fault estimates from the disturbances. Thanks to this decoupling, the observer produce a robust fault estimation based on a modified form of the standard adaptive observer. Simulation results are presented to illustrate the efficiency of the proposed RAFFE methodology.