M. Pietrzak-David

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.

Multi-machine multi-converter system for drives: analysis of coupling by a global modeling

More and more electrical systems are composed of several electrical machines and several electrical and/or mechanical converters. Such systems are called multi-machine multi-converter systems (MMS) and are described by a specific formalism. Specific coupling structures are defined in order to distribute the energy. Three coupling structures are pointed out in drive applications: electrical, magnetic and mechanical coupling devices. Despite allowing a better energy distribution, these coupling structures also induce also some constraints on power components and some perturbations between the associated conversion chains. Decoupling control strategies may be developed in order to minimize these interactions. Three examples of the different couplings are presented according to this specific formalism.

Doubly Fed Induction Machine speed drive for hydro-electric power station

The main idea of this paper is to use a variable rotation speed operating mode for a doubly fed induction machine (DFIM) associated with a reversible hydraulic turbine/pump device. The optimal efficiency of the energy conversion of this system is required. A high voltage power inverter supplies the DFIM rotor windings and it allows the rotor currents control. The control expressed in this paper enables to impose active and reactive powers exchanged between the stator side and the electrical supply network. Simulation results show pump and turbine working in steady state and in transient one (starting and speed evolutions). Finally, the authors propose to study the adequate size of the high voltage power inverter.

Power distribution law in a Doubly Fed Induction Machine

The paper deals with a Doubly Fed Induction Machine (DFIM). It presents a study of an active power distribution law between stator and rotor sides. The DFIM is supplied by two voltages PWM inverters in stator and rotor. The power distribution law imposes a relation between rotoric and statoric pulsations. Due to this relation, a new variation structure of the DFIM speed control is presented. The four quadrants working are considered. Simulation results under Matlab-Simulink illustrate the performances of the power distribution law.

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

Optimisation of a railway traction system drive control vs. slip perturbation

The purpose of this paper is to present a new drive control strategy for a railway traction system, robust vs. the loss of adherence perturbation. This new control strategy is based on an algorithm commutation. The specificity of the system drive is two induction motors with only one PWM inverter. For this study, the common mechanical load has been completely modelled, in particular the wheel/rail contact law, and represents a real railway traction system, coming from industry.

Feasibility study of wireless communication for the Double Fed Induction Machine

The Double Fed Induction Machine (DFIM) is an asynchronous wound-rotor machine. The use of this machine is very popular in the variable speed electrical drives. So its monitoring is important to protect motor from unexpected problems. Today, using wireless communication for electrical machines is interesting for both real time monitoring and diagnostic purposes. In this paper, we propose a system based on wireless communication IEEE 802.11 to control electrical machine. IEEE 802.11 standard is recommended for this type of applications because it provides a faster connection. Therefore, our contribution is to study a new technique to control and monitor the DFIM using wireless communication. Then, the communication protocol, software and hardware design used for the proposed system are presented in detail and the experimental results of our system are illustrated.

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/.

Reconstruction of MEMS accelerometer outputs in mobile fields by using Allan variance

Nowadays, a growing interest has been accorded to wireless communication in different fields especially in electrical domains. Due to the electromagnetic, Doppler and phases problems, the using of wireless communication in electrical motors is restricted. This paper presents primary studies which highlight the importance of using wireless sensors inside motor and pointed out a number of problems related to wire mechanical connection as vibrations and sliding. In order to solve this problem, a redundant network of distributed accelerators is used. Indeed; the proposed method allows predicting of reference signal. The evaluation of signal is achieved by using Allan variance technique and then an optimization method is applied to minimize errors between different signals. Many experimental tests have been done and Results are also interpreted and commented.