As a result of the development of modern vehicles, even higher accuracy standards are demanded. As known, Inertial Navigation Systems have an intrinsic increasing error which is the main reason of using integrating navigation systems, where some other sources of measurements are utilized, such as barometric altimeter due to its high accuracy in short times of interval. Using a Robust Kalman Filter (RKF), error measurements are absorbed when a Fault Tolerant Altimeter is implemented. During simulations, in order to test the Nonlinear RKF algorithm, two kind of measurement malfunction scenarios have been taken into consideration; continuous bias and measurement noise increment. Under the light of the results, some recommendations are proposed when integrated altimeters are used.
This paper describes a fault-tolerant controller (FTC) of induction motor (IM) with inter-turn short circuit in stator phase winding. The fault-tolerant controller is based on the indirect rotor field oriented control (IRFOC) and an observer to estimate the motor states, the amount of turns involved in short circuit and the current in the short circuit. The proposed fault controller switches between the control of the two components of measured stator current in the synchronously rotating reference frame and the control of the two components of estimated current in the case of faulty condition when the estimated current in the short circuit is not destructive of motor winding. This technique is used to eliminate the speed and the rotor flux harmonics and to assure the decoupling between the rotor flux and torque controls. The results of the simulation for controlling the speed and rotor flux of the IM demonstrate the applicability of the proposed FTC.
In order to develop a PM BLDC motor control system, which will be tolerant of selected faults, simulation work was first performed and then verified on a universal test stand. The results were published in earlier works. The next stage of works was the implementation of previously developed algorithms on the target research test stand – in this case, the prototype vehicle. This last stage of the laboratory work has been presented in this article, i.e. it has been presented the results of experimental research related to the reproduction of rotor angle position, used after the detection of a rotor position sensor fault. A new test stand with the laboratory prototype of a vehicle with two PM BLDC motors is presented. A zeroth-order algorithm (ZOA) was used as a fault compensation method. The effectiveness and usefulness of the previously proposed methods have been confirmed.
The paper presents a solution for sensorless field oriented control (FOC) system for five-phase induction motors with improved rotor flux pattern. In order to obtain the advantages of a third harmonic injection with a quasi-trapezoidal flux shape, two vector models, α1–β1 and α3–β3, were transformed into d1–q1, d3–q3 rotating frames, which correlate to the 1st and 3rd harmonic plane respectively. A linearization approach of the dual machine model in d–q coordinate frames is proposed by introducing a new additional variable “x” which is proportional to the electromagnetic torque. By applying the static feedback control law, a dual mathematical model of the five-phase induction motor was linearized to synthesize a control system in which the electromagnetic torque and the rotor flux can be independently controlled. The results shows the air gap flux shape in steady as well transient states under various load conditions. Moreover, the implemented control structure acquires fault tolerant properties and leads to possible emergency running with limited operation capabilities. The fault-tolerant capability of the analyzed machine was guaranteed by a special implemented control system with a dedicated speed observer, which is insensitive to open-phase fault situation. The experimental tests have been performed with single and double-open stator phase fault. A torque measurement was implemented to present the mechanical characteristics under healthy and faulty conditions of the drive system.
Wind energy has achieved prominence in renewable energy production. There fore, it is necessary to develop a diagnosis system and fault-tolerant control to protect the system and to prevent unscheduled shutdowns. The presented study aims to provide an experimental analysis of a speed sensor fault by hybrid active fault-tolerant control (AFTC) for a wind energy conversion system (WECS) based on a permanent magnet synchronous generator (PMSG). The hybrid AFTC switches between a traditional controller based on proportional integral (PI) controllers under normal conditions and a robust backstepping controller system without a speed sensor to avoid any deterioration caused by the sensor fault. A sliding mode observer is used to estimate the PMSG rotor position. The proposed controller architecture can be designed for performance and robustness separately. Finally, the proposed methodwas successfully tested in an experimental set up using a dSPACE 1104 platform. In this experimental system, the wind turbine with a generator connection via a mechanical gear is emulated by a PMSM engine with controled speed through a voltage inverter. The obtained experimental results show clearly that the proposed method is able to guarantee service production continuity for the WECS in adequate transition.
The paper presents the result of an evaluation of the performance of different message broker system configurations, which lead to the construction of the specific architecture guidelines for such systems. The examples are provided for an exemplary middleware messaging server software - RabbitMQ, set in high availability - enabling and redundant configurations. Rabbit MQ is a message queuing system realizing the middleware for distributed systems that implements the Advanced Message Queuing Protocol. The scalability and high availability design issues are discussed and the possible cluster topologies and their impact is presented. Since HA and performance scalability requirements are in conflict, scenarios for using clustered RabbitMQ nodes and mirrored queues are interesting and have to be considered with specific workloads and requirements in mind. The results of performance measurements for some topologies are also reported in this article.
The paper presents the analysis of different fault states in drive systems with multiphase induction motors. The mathematical models of a five-phase and six-phase induction motor and the MRASCC estimator have been presented and the description of the Space Vector Modulation has been shown. The Direct Field-Oriented Control (DFOC) system is analyzed. Results of the simulation and experimental studies of the Direct Field-Oriented Control systems in the fault conditions are presented. The author’s original contribution includes analysis and studies of the DFOC control method of a five-phase induction motor resistant to the motor speed sensor fault with the use of the MRASCC estimator.