Papers by Xavier Kestelyn
Electric Power Components and Systems, 2007
Abstract In order to increase the power capability of direct-drive PM wind generators with respec... more Abstract In order to increase the power capability of direct-drive PM wind generators with respect to established quality criteria like the electromagnetic torque and the power transferred to the grid, a polyphased multi-star system is studied. The influence of the ...
Electrical marine propulsion systems are characterized by very high level requirements in terms o... more Electrical marine propulsion systems are characterized by very high level requirements in terms of compactness, acoustic behavior and reliability. In this particular context, the use of multiphase PM machines associated with VSI drives appears to be a very efficient solution. Presented work focus on the use of such a system in open circuited phase fault conditions. With this kind of system it is possible to determine optimal current references which maximize the torque density of the system when one or two phases are open circuited. Classical linear controllers (as PID for example) cannot provide a correct tracking of these optimal current references because they have a highly dynamical behavior. We propose in this paper to combine this optimal current reference generation with High Order Sliding Mode (HOSM) control. This kind of solution allows a good tracking of these unconventional current references with a fixed switching frequency for the VSI. This method is validated experimentally using a low power experimental set-up which associates a 5-phase PM machine with a DSP controlled IGBT 5-leg VSI drive.
ABSTRACT Widely used for high-speed high-precision motion control in the electronics, nuclear and... more ABSTRACT Widely used for high-speed high-precision motion control in the electronics, nuclear and automotive industries, gantry stages are usually controlled using independent axis control. In order to avoid the effects of the mechanical coupling over synchronization and tracking errors, we propose a control on a modal reference frame. First, the system is modeled with respect to the center of mass of the moving beam and a modal transformation is applied to obtain the motion equations on a decoupling base. Next, a model-based control scheme is deduced with the minimization of synchronization and tracking errors as objectives. Finally, experimental results show that the proposed modal control scheme leads to an improved motion control of the point-tool in comparison with the present industrial control.
ABSTRACT In order to get a low cost mild hybrid system, a global objective is to keep the actual ... more ABSTRACT In order to get a low cost mild hybrid system, a global objective is to keep the actual thermal engine architecture as in Figure 1. As consequence, the current clawpole synchronous automotive generator must be replaced by a new more powerful electrical machine but with the same large speed range [0-18000 rpm]. In the project, a power of 15 kW and a DC bus voltage of 60V have been chosen to provide a regenerative breaking at minimum cost. With this payload (250A for the DC bus current), a five-phase machine appears to be interesting because MOSFET transistors of the voltage source inverter (VSI) have not to be used in parallel configuration (only two rated 150A transistors per leg for the VSI). As the speed range is large, a flux weakening must be applied. As the five-phase drives have more degrees of freedom than three-phase ones, different flux weakening strategies can be considered. The aim of this paper is to compare one of them.
European Physical Journal-applied Physics, 2008
This paper deals with fault tolerant multiphase electrical drives. The quality of the torque of a... more This paper deals with fault tolerant multiphase electrical drives. The quality of the torque of a vector-controlled Permanent Magnet (PM) Synchronous Machine supplied by a multi-leg Voltage Source Inverter (VSI) is examined in normal operation and when one or two phases are open-circuited. It is then deduced that a seven-phase machine is a good compromise allowing high torque-to-volume density and easy control with smooth torque in fault operation. Experimental results confirm the predicted characteristics.
This paper deals with control in fault operation of a seven-phase permanent magnet synchronous ma... more This paper deals with control in fault operation of a seven-phase permanent magnet synchronous machine supplied by a seven-leg voltage source inverter (VSI). Using a multi-machine description, a seven-phase machine which presents a special ability to be controlled with only five phases supplied has been designed. The machine is presented and experimental results are provided when two phases are opened. In a first case of no change of classical control, high torque ripples are observed. In a second case, a specific control deduced from the multi-machine modelling is suggested for reducing torque ripples
This paper proposes a simple way to control multi-phase drives in open-phase conditions. Contrary... more This paper proposes a simple way to control multi-phase drives in open-phase conditions. Contrary to existing methods, current references are not recomputed and the control scheme is kept the same to run in open-circuited phase condition. In order to work in fault-conditions, the number of degrees of freedom of the control scheme is adapted to the number of degrees of freedom of the drive. Since a particular attention has to be dedicated to the structure and controller tuning, harmonic content of induced perturbations in fault mode is exhibited. Simulation and experimental results are presented to show the effectiveness and the limitations of the proposed method.
ABSTRACT This paper deals with the modelling and control of a three-phase induction machine suppl... more ABSTRACT This paper deals with the modelling and control of a three-phase induction machine supplied by three independent voltage sources when one phase is open-circuited. The modelling of the overall system leads to design a dedicated controller tuned with the generalised stability margin method in order to reduce the pulsating torque. The consequences of the new closed-loop control on the induction machine and the VSI are evaluated to quantify the currents, voltages and copper losses increasing. Finally, simulation and experimental results are achieved and show the global performances of this ripple torque reduction method.
This paper deals with a vector control of n-phase permanent magnet synchronous machine. To use co... more This paper deals with a vector control of n-phase permanent magnet synchronous machine. To use control algorithms already developed for sine-wave 3-phase machines, the spectrum of back electromotive force (EMF) must contain only odd 2k+1 harmonics which verify the following inequality, n k < + ≤ 1 2 1 . In an experimental vector control of a 5-phase drive, two usual algorithms of sine-wave 3-phase machine are thus used to supply a machine with trapezoidal waveform back EMF. In this case, the first and third harmonics are used to produce torque: the other harmonics, and particularly the 7 th one, induce effects as torque ripples and parasitic currents.
This paper deals with design constraints of a 7-phase permanent magnet synchronous machine (PMSM)... more This paper deals with design constraints of a 7-phase permanent magnet synchronous machine (PMSM) supplied by a 7-leg voltage source inverter. The optimum back electromotive force waveform is determined in order to get maximum torque for a given DC bus voltage
This paper deals with modeling and control of a three-phase permanent magnet synchronous machine ... more This paper deals with modeling and control of a three-phase permanent magnet synchronous machine (PMSM) with sinusoidal back electromotive forces (emf) under supply fault conditions. The overall system is modeled thanks to the energetic macroscopic representation (EMR) formalism considering that a fusible element opens the phase circuit. Using systematic inversion rules of the EMR, a maximum control structure (MCS) is deduced. Based on the analysis of degrees of freedom (DOF) of the drive, two control strategies for constant-torque under supply fault conditions are inferred. One method balances generated perturbations caused by the supply fault and the other one consists in modifying current controller's structure. These methods are validated through simulations with Matlab software
This paper deals with the series connection of two 5-phase synchronous machines supplied by a sin... more This paper deals with the series connection of two 5-phase synchronous machines supplied by a single 5-leg voltage source inverter. Using a specific modelling tool, design constraints on both machines are defined in order to control them independently. The effects of harmonics of back-electromotive force are then examined and improved control is deduced
IEEE Transactions on Industrial Electronics, 2011
This paper deals with the generation of optimal current references for multiphase permanent-magne... more This paper deals with the generation of optimal current references for multiphase permanent-magnet (PM) synchronous machines in normal or fault mode (open-circuited phases). Current references are computed in order to keep a constant torque while minimizing instantaneous joule losses. In comparison with commonly used scalar methods, a vectorial approach makes it possible to reduce the number of computations in order to generate optimal current references in real time. In addition to this, since current references are expressed in terms of physical parameters of the machine, this approach can be used to evaluate the influence of machine parameters over the control performances. Finally, experimental results of a surface-mounted PM five-phase synchronous machine are provided in order to demonstrate the proposed strategy.
Causal ordering graph and energetic macroscopic representation are graphical descriptions to mode... more Causal ordering graph and energetic macroscopic representation are graphical descriptions to model electromechanical systems using integral causality. Inversion rules have been defined in order to deduce control structure step-by-step from these graphical descriptions. These two modeling tools can be used together to develop a two-layer control of system with complex parts. A double-drive paper system is taken as an example. The deduced control yields good performances of tension regulation and velocity tracking
European Journal of Electrical Engineering, 2010
This paper presents an easy way to model multiphase electrical drives in fault supply conditions.... more This paper presents an easy way to model multiphase electrical drives in fault supply conditions. The presented technique makes it possible to simulate the drive in various configurations with keeping the same integral model established in normal mode. Simulations of a seven-leg seven-phase drive are carried out and compared to experimental measurements.
This paper presents a physical dynamic modelling of a dual-drive gantry stage which takes into ac... more This paper presents a physical dynamic modelling of a dual-drive gantry stage which takes into account the rigid body motion and the first flexion mode. It is used to study the influence of the mechanical coupling between the two parallel axes on the global positioning performances. Indeed, dual-drive mechanisms are commonly controlled with two independent and symmetrical position controllers while the mechanical structure is not symmetrical. This control strategy leads to an imperfect synchronism between the two axes and the mechanical coupling is submitted to huge levels of strain. In this paper, the influence of the stiffness of the joints and of the mass distribution is particularly discussed.
ABSTRACT Dual-drive gantry stages are used for high-speed high-precision motion control applicati... more ABSTRACT Dual-drive gantry stages are used for high-speed high-precision motion control applications such as flat panel display manufacturing and inspection. Industrially, they are usually controlled using independent axis control without taking into consideration the effect of inter-axis mechanical coupling over positioning accuracy and precision. To improve this and minimize the effect of mechanical coupling over synchronization and tracking errors, we propose to model and control the dual-drive gantry stage on a decoupling basis. This approach allows representing the highly coupled Multiple Input Multiple Output (MIMO) system as a set of independent Single Input Single Output (SISO) systems. Based on this representation, a model-based feedback-feedforward control scheme is deduced. Experimental results show that the proposed decoupling basis control scheme leads to an improved motion control of the point-tool in comparison to the present industrial control.
Industrial control of Dual-Drive Moving Gantry Stage Robots is usually achieved by two independen... more Industrial control of Dual-Drive Moving Gantry Stage Robots is usually achieved by two independent position controllers. This control structure does not take into account the mechanical coupling between the two actuators that leads to a reduction of the overall performances. In this paper, a physical dynamic lumped parameters model of an industrial robot based on structural, modal, and Finite Element Method analysis is proposed, experimentally identified and validated. Then, using simple inversion rules of the Causal Ordering Graph formalism, a control structure is deduced in a systematic way. The solution is finally simulated and shows that it is possible to obtain better performances than the industrial control.
This paper deals with the generation of optimal current references for multi-phase permanent magn... more This paper deals with the generation of optimal current references for multi-phase permanent magnet machines with open-circuited phases. Compared to classical methods, the use of a vectorial approach makes it possible to generate optimal current references, from a copper losses point of view, on-line. This method is viable whatever the number of open-circuited phases. As an example, a five-phase machine
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Papers by Xavier Kestelyn