B. de Fornel

Control structures for multi-machine multi-converter systems with upstream coupling

A multi-machine multi-converter system formalism has been proposed to describe systems composed of several electrical machines and converters. This description points out coupling elements, which have to distribute energy. Control structures have already been proposed for systems with downstream coupling. This paper is focused on control structures for systems with upstream coupling. Several solutions can be found by moving control blocks.

Dynamic reconfiguration of control and estimation algorithms for induction motor drives

In this paper, the authors present the concept of dynamic reconfiguration (DR) of algorithms applied to induction motor drives. A classification according to several criteria is proposed as well as two practical examples. The first example concerns a partial dynamic reconfiguration by combination of rotor flux estimation algorithms for a field oriented control (FOC) strategy. The second example presents a partial dynamic reconfiguration of direct torque and stator flux control (DTSFC) algorithms. Simulations and experimental results are given that confirm the interest of the proposed dynamic reconfiguration approach.

A Fault Tolerant Operating System in a Doubly Fed Induction Machine Under Inverter Short-circuit Faults

This paper presents an original strategy of fault tolerant operating in case of doubly fed induction machine (DFIM). The considered fault is short-circuit of inverters leg (T1 and T2). The proposed strategy permits the reconfiguration management of both inverter topology and DFIM field oriented control. Consequently, the drive continuous operation is guaranteed in the presence of the damaged inverter. Simulation results are presented to emphasize the effectiveness of the proposed method

Loop-shaping H∞ control for a doubly fed induction motor

This paper deals with a doubly fed induction machine (DFIM) where both sides are supplied by two PWM inverters. The study consists in elaborating a robust vector control of the machine by the loop- shaping Hinfin approach. The Hinfin loop-shaping theory is presented in brief; then it is applied to the control of the DFIM. The simulation results prove that the implementation of the Hinfin controllers for currents, fluxes and speed loops leads to excellent robustness in stability and good dynamic performance even with large electrical and mechanical parameters uncertainty.

Dead time effect in a railway traction system

The aim of this paper is to establish the description of how dead time, which is introduced in the PWM voltage inverter affects the performance of a railway traction system conceived by Alstom-Transport Inc. By means of a model of this high power system, the authors have imposed three different simulation operating conditions using the SABER solver of Analogy Inc. When simulating the system with dead time effect, two different rates of dead time to switching period are defined: 5% and 9%. There are interactions caused by the dead time and so, a stabilisation strategy has been implanted and simulated, in order to reduce the systems perturbations. This strategy has to respect some constraints, because it is not possible to change neither input filter structure nor any input filter component value. And it is not feasible either, to measure or to control the voltage input E and the inductance current i/sub L/.

Control structures for multi-machine multi-converter systems with several couplings by criteria merging

A multi-machine multi-converter system formalism has been proposed in order to describe systems composed of several electrical machines and converters. The keys of such systems are coupling devices, which have to distribute energy. Control structures have also been suggested according to an inversion principle. The inversions of coupling devices have been made using repartition and weighting criteria. In this paper, systems with several coupling are studied. Several control structures can be found. One of them leads to shift some control blocks and to merge the repartition and weighting blocks. A railway traction system is given as example

Design of rotor and stator converters for a Double Fed Induction Machine

The paper deals with a doubly fed induction machine (DFIM) supplied by two PWM voltages inverters. The authors impose a power distribution law between stator and rotor sides, and define the power converter designs. They justify that, in the same power conditions, the proposed DFIM speed drive is better then usual induction motor one. To design both inverters, two arguments are studied. The first one is electrical aspect which requires the maximum values of current and voltage from each inverter. The second one is thermal aspect linked to the heat stress of power components defined by the conduction and switching losses

Hybrid simulation of a current fed asynchronous machine

In this article the authors present a hybrid simulation program for variable speed drives comprising an AC machine current fed by a static convertor. The examination here beare upon a current fed asynchronous machine. The authors give the details of the utilization of this program, and show the results obtained in comparison with experimental results. They also indicate the conditions for the use of this program.