Mircea Ruba

Segmental Stator Switched Reluctance Machine for Safety-Critical Applications

In safety-critical systems, faults can cause life losses, environmental degradation, or significant financial losses. In this paper, a segmental stator switched reluctance machine is proposed for such applications. A short overview of its design is given. Its fault tolerance is investigated by dynamic simulations and laboratory tests. It is demonstrated via both methods that the proposed machine is able to have a continuous operation despite five severe winding fault conditions.

Analysis of Fault-Tolerant Multiphase Power Converter for a Nine-Phase Permanent Magnet Synchronous Machine

The use of electrical drives and machines with very high number of phases is not a common topic of researchers, because of the control difficulties and the important number of switches needed to assure the operation in faulty conditions. The advantage of using a high number of legs/phases provides smooth mechanical performances (i.e., reduced torque ripples), without increasing the number of poles (this last approach, is usually applied for fractional-slot machines, increases frequency, and consequently the iron loss). The authors are proposing a nine-phase drive to supply a permanent magnet synchronous machine. A prototype of nine-phase drive machine is constructed. Its capability to operate in faulty conditions will be evaluated by numerical computation and tests. It will be proved that the proposed solution can operated even in the most severe faulted conditions (78% of the drive machine being faulted).

Study on fault tolerant switched reluctance machines

The papers goal is to compare a usual switched reluctance machine and a fault tolerant variant of it. By coupled Flux 2D and Simulink transient simulations the behaviour of the fault tolerant drive system under different winding fault conditions were studied. It was proved that using the proposed machine structure and converter topology same torque capability of the machine in faulty states as in healthy conditions can be assured. A short discussion on fault-tolerant converters is included in the paper, too.

Study on a simplified converter topology for fault tolerant motor drives

Some of the recent research activities in the area of electrical machines and drives for critical applications (such as aerospace, defence, medical, nuclear power plants, etc.) are focused on looking for various special motor and converter topologies. Nowadays by the help of recent technological advances and developments in the area of power electronics and motor control the fault tolerant electrical machine and drive concept is at a level where it begun to be feasible to be used in practice [1]. Therefore any new results could be of real interest for all the specialists working in these fields. In the paper a simplified power converter topology is proposed for a nine-phase fault-tolerant permanent magnet synchronous machine. By coupled Flux 2D and Simulink transient simulations the behaviour of the drive system under different winding fault conditions is studied. It is proved that using the simplified converter topology near the same torque development capability of the machine in faulty states can be assured. Short discussion on making the converter also fault-tolerant is included in the paper, too.

Comparison of the main types of fault-tolerant electrical drives used in vehicle applications

A comparative study of several fault-tolerant electrical drives is presented in this paper. As the application is concerned, the authorspsila attention was oriented towards the vehicle transportation. Thus, the main electrical drives under study are: the induction, the switched reluctance and the permanent magnet synchronous machine, respectively. The present work will explore the aforementioned drivespsila capabilities in terms of fault-tolerant operation. The authors present a substantial study for the fault-tolerant issue in electrical drives by using finite element method (FEM). During this numerical analysis many phenomenon will be emphasized and, coming together with some tests, final conclusions will be depicted.

Using co-simulations in fault tolerant machine’s study

The Switched Reluctance Machine (SRM) is ideal for safety critical applications (aerospace, automotive, defense, medical, etc.) where it is desirable that the electrical drive system to be fault tolerant. During the design of a fault tolerant electrical drive system it is indispensable to use advanced simulation techniques. Finite elements method (FEM) based magnetic field computation programs are the most precise tools in simulating the electrical machines. These programs must be embedded in a general simulation platform. The paper deals with the analysis of a proposed SRMs fault tolerant capacity. The study was performed by means of a coupled simulation program. The main program was built up in Simulink, the most widely used dynamic system simulating platform. The SRM was modeled using the Flux 2D FEM based numerical field computation program. The machines model was connected to the main program thru the Flux-to-Simulink link. This co-simulation technique proved to be a very useful tool in the fault tolerance study of the proposed SRM.

On fault tolerance increase of switched reluctance machines

The Switched Reluctance Machine (SRM) is ideal for safety critical applications (aerospace, automotive, defense, medical, etc.) where it is desirable that the electrical drive system to be fault tolerant. The phase independence characteristics of the SRM enable it to operate (at lower power and higher torque ripples) also under partial phase failure conditions. Its reliability can be improved during its conception stage by applying special fault tolerant designs and in its exploit by monitoring its condition and applying fault detection techniques. In the paper first the most typical faults and their detection methods are summarized. In the second part of the paper a fault tolerant SRM structure is proposed and analyzed by means of simulations. The obtained results emphasize the usefulness of fault tolerant SRMs.

Novel modular switched reluctance machine for safety-critical applications

Electrical machines and drives used in various safety-critical applications are of special design in order to achieve the required fault tolerance level. In the paper a novel modular fault tolerant switched reluctance machine is proposed and studied. It is proved by means of dynamic simulations that the proposed machine is able to have continuous operation also despite of five severe winding fault conditions.

Novel modular fault tolerant switched reluctance machine for reliable factory automation systems

Electrical machines and drives used in diverse critical fields like advanced factory automation systems, automotive and aerospace applications, military, energy and medical equipment, etc.) require both special motor and converter topologies to achieve high level fault tolerance. In the paper a novel modular fault tolerant switched reluctance machine is proposed. Its stator is built up of simply to manufacture and to replace modules. The machine is able to have continuous operation despite winding faults of diverse severity. It is fed by a special power converter having separate half H-bridge leg for each coil. Thus a complex and high reliable electrical system is obtained. By advanced dynamic co-simulations (using a coupled Flux 2D and Simulink® program) the behaviour of the drive system under five winding fault conditions are studied. The obtained results prove the fault tolerant capacity of the proposed machine.

Fault tolerant switched reluctance machine for wind turbine blade pitch control

The papers goal is to accomplish a study regarding the usefulness of a fault tolerant machine in wind turbine pitch control. The pitch control both helps to catch the wind at the optimal angle of attack of the blades airfoil and to turn the blades out of the wind when maximum speed is exceeded. To fulfill this assignment electrical machines are used to control the blades pitch angle function of winds speed. The faults that can occur in electrical machines can stop the pitch control system, decreasing drastically the efficiency of the wind turbine. Fault tolerance ability of the pitch controlling machines can avoid such issues. In the paper a fault tolerant switched reluctance machine is studied. As it being simple and cheap it is optimal for such vital applications. Numerical field computations were used to analyze the machines behavior. An advanced cosimulation was performed by coupling two simulation programs in order to study the machines drive system and fault tolerance capacity.