Jean-Paul Louis

Control of a doubly fed induction generator for aircraft application

This paper presents a variable speed constant frequency system (VSCF) for aircraft applications. The system consists in a doubly fed induction generator (DFIG) connected to a stand-alone aircraft grid through its stator windings. It uses back-to-back PWM converters connected to the rotor for sub and super synchronous speed operation. A permanent magnet synchronous machine (PMSM) connected to a variable speed prime mover supplies these converters. The control strategy of the DFIG is carried out through a rotor-flux inner control loop and a stator-voltage outer loop. The vector control of the PMSM and the DC link voltage regulation are also presented in this paper. Simulation results demonstrate the feasibility of the proposed system.

Modeling for control of non-sinewave permanent-magnet synchronous drives by extending Park's transformation

An extension of Parks transformation is proposed for non-sinewave permanent-magnet synchronous machines with constant airgap. For sinewave machines, Parks classical transformation allows working within the rotors reference, so that the vector of the rotor fluxes variations would have just one component Φ′rq. For the non-sinewave machines, a new reference frame is proposed, which permits to obtain a simple torque expression, through setting at zero one of the components of the vector of the rotor fluxes variations. By means of this modeling, optimal steady state currents have been computed for this kind of drive. Extended Park model has been validated through a finite element code. This analytic model is here used to analyse the steady state (comparison with 120° voltage control is conducted), but is destined to determine dynamic control laws, particularly vector control.

Design of an output LC filter for a doubly fed induction generator supplying non-linear loads for aircraft applications

This paper presents a variable speed constant frequency (VSCF) system for aircraft applications. More accurately, it focuses on the design of an output filter to reduce the influence of non-linear loads. The VSCF system consists in a doubly fed induction generator (DFIG) supplying a stand-alone aircraft grid through its stator windings. It uses back-to-back PWM converters connected to the rotor for sub and super synchronous speed operation. A permanent magnet synchronous machine (PMSM) connected to a variable speed prime mover supplies these converters. An efficient control strategy of the system was presented in a previous paper for linear loads. However, non-linear loads such as 6-pulse diode rectifiers, that can represent up to 50% of the total load introduce undesirable current harmonic components. A LC output filter is thus designed to eliminate them. Simulation results demonstrate the feasibility of the proposed system.

Control of a DC generator based on a Hybrid Excitation Synchronous Machine connected to a PWM rectifier

This paper deals with the control of an hybrid excitation synchronous generator which is used to supply an isolated grid for aircraft applications. This grid is supposed to be a 270 V DC bus. Thus, a rectifier is required between the machine and the DC bus. Two structures can be used: diode or PWM rectifier. Here, only the structure with a PWM rectifier is studied. With a such system, it is possible to use a vector control applied to the structure in order to obtain minimal copper losses in the machine. The controller is synthesized here using a methodology based on a graphical representation of the system and then it is validated by simulation

Presentation of a control law for IM drive based on the dynamic reconfiguration of a DTC algorithm and a SVM-DTC algorithm

In this paper, the authors present an original control law for induction motor drive. It is based on a dynamic reconfiguration of a basic direct torque control (DTC) algorithm and a direct torque control algorithm associated to space vector modulation (SVM-DTC). The criterion of reconfiguration concerns the state of the machine. Indeed, during transient states DTC algorithm is activated in order to get the best torque dynamic. Then, at steady-state, a SVM-DTC algorithm is preferred because it allows to reduce significantly the torque ripples. Besides, an original and well-adapted modelling based on a polar representation of the state variables is also introduce. Finally, experimental results are presented that confirm the interest of this solution.

Predictive control of a doubly-fed induction generator connected to an isolated grid

This paper presents a predictive control of a doubly fed induction generator (DFIG) dedicated to embedded systems power supplies like aircraft electrical generation systems. In such applications, efficiency and weight are the main performance criteria for the choice of adapted structures. The predictive control presented here is synthesized on the basis of a graphical representation of the DFIG: dynamical equivalent circuit which is adapted to the design of controllers dedicated to generators. The controller proposed here is then validated by simulations and experimental results

Reduction of torque undulation and extension of the Park's transformation applied to non-sinusoidal saturated synchronous motors

This paper present the principle of an extended field oriented control. This control strategy follows from an extension of the Parks transformation, suitable for non-sine synchronous motors with salient poles. In particular, we highlight that the structure of the classical field oriented control is kept in the case of non-sine motors provided minor modifications. The presented method allows to regulate constant values in steady state while applying nonsine currents to the motor. The shape of these non-sine currents is predetermined so as to minimise the steady state torque undulation.

Graphical representation of electrical generators using dynamical equivalent circuits

Many graphical representations are used for the modelling and the control design of dynamical systems. But it is usually necessary to learn a specific vocabulary. In this paper, a new methodology of design is proposed for the control of electrical generators, based on dynamical equivalent circuits. Thus, in this case, the only vocabulary which is required (electrical equivalent circuits) is already known by electrical engineers and researchers. This user-friendly method is applied to the design of the control of a doubly-fed induction machine used as a variable speed constant frequency (VSCF) generator

Rigorous discrete modelling for switched reluctance drive fed by asymmetrical half bridges with full wave voltage in discontinuous mode

A modelling for switched reluctance drive fed by asymmetrical half bridges with full wave voltage in discontinuous mode is presented. A description of the system in terms of differential and switching equations leads directly to the sensitivities of the state vector with respect to the initial conditions. It is shown that the steady state can be obtained with Newtons method and these sensitivities. Then the system is linearized around its steady state to obtain a rigorous linear discrete time model which is a first order model.<<ETX>>