EPE Association: EPE 2003 - Topic 05a: Optimal Control, Robust Control, Non-Linear Control

EPE 2003 - Topic 05a: Optimal Control, Robust Control, Non-Linear Control
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2003 - Conference > EPE 2003 - Topic 05: APPLICATION OF CONTROL METHODS TO ELECTRICAL SYSTEMS > EPE 2003 - Topic 05a: Optimal Control, Robust Control, Non-Linear Control

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   Active vibration suppression using DTC drive and automatic parameter identification of two mass system
By H. Sarén; O. Pyrhönen [View]
[Download]

Abstract: In this paper active mechanical vibration suppression has been investigated in DTC synchronous motor drive. Phenomena in two mass system with flexible shaft was studied. A simple method to identify parameters for mechanical two mass system is presented. State feedback based optimal speed control was tested.

   Robust speed control of a low damped electromechanical system: application to a four masses experimental test bench
By S. Poullain; J. Sabatier; P. Latteux; J-L. Thomas; A. Oustaloup [View]
[Download]

Abstract: Robust speed control of a low damped electromechanical system with backlash is studied, when the controlled load angular speed can not be measured. The proposed control strategy combines a Luenberger observer (load angular speed and load torque disturbance estimations) and a robust CRONE controller. The proposed control strategy is applied to a four mass experimental test bench.

   CPWL approximation for solar panel control
By Y. Labit; G. Garcia; C. Alonso [View]
[Download]

Abstract: This communication deals with the control of a solar panel approximated by canonical piecewise linear modelling (CPWLM). The proposed approach consists on the panel modelling by a set of uncertain linear models via a piecewise linear model. The global law is designed by scheduled local robust control laws taking into account some performances.

   Widening the stability range of a PWM inverter using a nonparametric chaos control
By B. Robert; H.H.C. Iu; M. Feki [View]
[Download]

Abstract: Out of their usual operating zones, many static converters can exhibit undesirable aperiodic behaviours. Sometimes chaotic and strange attractors appear and must be avoided by an appropriate control. Usual correctors fail to stabilize unstable periodic orbits (UPOs) embedded in the chaotic zones. Specific methods must be used in order to control chaos. However, most of them need a precise knowledge of the model in order to investigate the nonlinear dynamics. Thus, they are not robust because of their dependence on the parameters of the model. In this paper, a simple corrector is improved to stabilize the fundamental periodic operating mode by using a robust model free chaos control. The converter under control is a current programmed inverter driven by a low frequency reference. The stability range is approximately doubled and the sampled current error is reduced.

   GPC robustification by the Youla parameter - Application to position control of an induction motor
By P. Rodríguez; D. Dumur; E. Mendes [View]
[Download]

Abstract: This paper presents a two-steps design procedure for Generalized Predictive Control (GPC) controllers, and the experimental results obtained with this algorithm applied to the position control of an induction motor. In the first step of the design procedure, an initial GPC controller is required to ensure the desired input/output tracking behaviour. This initial controller is then robustified considering temporal and frequency constraints, which are formulated by means of the Youla parametrization within a convex optimisation framework. The optimal Youla parameter is finally obtained by solving this optimisation problem. The Youla parametrization permits closed loop convex specifications, and the two-degrees of freedom GPC controller allows to robustify the initial controller without changes in the input/output behaviour. Moreover, a compromise between robustness and closed loop behaviour, like disturbance rejection, can be easily managed. An application to the position control of an induction motor drive is presented, where the robustness of the initial GPC controller regarding model uncertainties in high frequency is enhanced while respecting a temporal template for the disturbance rejection. The results are finally compared to those obtained with an anticipative PID controller.

   Robust control via H2/Hinfinity approach applied to an induction motor
By S. Cauet; L. Rambault [View]
[Download]

Abstract: This paper deals with a robust H2/Hinfinity technique applied to an induction motor. In order to robustify a linearizing decoupled feedback against parametric variations, H2/Hinfinity controllers with a reference model are added. The main interests are performances and real decoupling between the rotor flux and the speed. Real time implementation are carried out.

   Tailoring ripple and spectrum of chaotic DC-DC converters
By J. Weber; O. Woywode; H. Gueldner [View]
[Download]

Abstract: Chaotic dc-dc converter operation—associated with a broad (non-peaky) spectrum—was suggested to reduce the electromagnetic interference of a switched mode power supply. Chaotic operation is, on the other hand, accompanied by a large ripple. The paper discusses methods (implemented into the inner current loop) that allow for tailoring ripple and spectrum. The methods are verified by simulation and experiment. The voltage feedback loop is closed around the inner current loop. The response of the converter to a step load change under chaotic and periodic operation is compared.

   Speed controller for drives with critical torsional conditions
By K. Schiftner [View]
[Download]

Abstract: The paper presents a speed controller for torsionally stressed drives. The significant feature of the system is the suppression of the torsional vibrations as well as its robustness with respect to indeterminate system parameters and modelling errors. The theoretical approach is verified herein in various drives for high-inertia output load.

   Robust sensorless induction motor control for electric propulsion ship
By F. Terrien; S. Siala [View]
[Download]

Abstract: This paper deals with robust sensorless induction motor control applied to electrical ship propulsion. The control fulfils the marine process specificities and constraints. The flux estimation is based on a two step adaptative Kalman Filter (KF). A fourth order KF estimates the flux and the currents, then the rotational speed is estimated by integration of a non-linear equation of estimated flux and current errors. RST regulators are used rather than the classical PI to improve the robustness/performances compromise.

   Near-time-optimal position control of electrical drives with permanent magnet synchronous motor
By J. Vittek; T. Baculák; S.J. Dodds; R. Perryman [View]
[Download]

Abstract: The paper presents a ‘near-time-optimal’ (NTO) position control strategy for electrical drives with permanent magnet synchronous motors, where the responses to changes in the demanded position of the driven mechanism should ideally take place in minimum time. The principles of time-optimal-control and forced dynamic control are combined to form a novel method of achieving a nearly time optimal position control performance in drives equipped with controllers enabling close following of time varying reference position inputs. The position response of a real-time model of the closed-loop time optimal control system provides the reference input to the drive control loop. Experimental results show good correspondence with theoretical predictions and confirm the near time optimal control.

   A simple approach to improve sliding mode control in induction motor drives
By W. Jamal; M. S. Khanniche; P. A. Mawby [View]
[Download]

Abstract: In the past, Variable Structure Control with Sliding Mode (VSC-SLM) has been successfully applied to versatile control applications, in which robustness against parametric variations and external disturbances are guaranteed. Therefore, it is usefully employed in systems with uncertain and time-varying parameters such as the induction motor (IM) drive. However, with the heritage of past control experience, the chattering effects about the sliding surface remains a major concern and as a result it has limited its practical application in high performance drive systems. This paper presents a method to introduce fuzzy logic algorithms into the design of VSC-SLM, in order to alleviate the chattering problems and to improve the dynamics of the IM drive. The theoretical bases for this algorithm are given, and a concrete scheme for constructing the proposed control system is presented. A computer model for the proposed controller is constructed and simulated when it is applied to the outer loop speed control of an IM drive. The proposed method has achieved a considerable improvement of the drive dynamics in contrast to those obtained with the conventional VSC-SLM.

   Robust speed control of PMSM servodrive based on ANN application
By T. Pajchrowski; K. Urbanski; K. Zawirski [View]
[Download]

Abstract: In the paper an application of artificial neural network to design a robust control of PMSM servodrive speed was presented. Proper training of ANN ensures a control robust against variation of moment of inertia. Simulation and laboratory results proved good robustness of the system.

   Hybrid theory based model predictive control of electrical drives with friction
By I. Petroviæ; M. Baotiæ; L. Matiæ; N. Periæ [View]
[Download]

Abstract: In this paper hybrid theory has been applied to design a state-feedback control law of an electrical drive with friction. The drive is modeled as a piecewise affine (PWA) system and a finite time optimal control problem is formulated for such a hybrid system. Three most often used friction models are considered and compared based on their suitability for the PWA description. It is shown that a resetintegrator friction model gives a PWA model of smaller complexity than LuGre and Karnopp friction models. A state-feedback optimal control law in a form of a look-up table is then derived via dynamic programming. The control system behavior is tested by computer simulations. The results indicate that the proposed control strategy is a valuable alternative to the currently used control strategies.

   A comparison of controller designs for VSC-HVDC
By M. Durrant; H. Werner; K. Abbott [View]
[Download]

Abstract: The VSC current controllers of a VSC HVDC transmission system are designed on a 2 state linear VSC model using IMC and LQR design methods. The controller performance on the linear model, a more complex analytical model including PLL and AC ¯lter dynamics, and a rigorous PSCAD model is compared. The increasing discrepancy between the two state model and the other models as SCR is reduced is explained and the e®ects on control performance are demonstrated.

   A robust fuzzy-sliding mode position controller for motor drives systems with flexible shafts
By J. Arellano-Padilla; G.M. Asher; M. Sumner [View]
[Download]

Abstract: This paper reviews and develops a new approach to Fuzzy-Sliding Mode Control (FSMC) for the robust position control of practical motor drive systems operating with elastic transmissions and loads with variable mechanical parameters. Robustness is achieved through the definition of a real time reference transient trajectory eS for the switching function of the Sliding Mode Control (SMC). The integration value of eS is the input for a fuzzy interpolation between control laws corresponding to the boundary values of the plant parameters variations. The paper reviews the background of the approach and develops a formal design procedure for the fuzzy interpolation to yield robust performance for large range of plant parameter variations. Experimental results are presented.

   Control design for VSC HVDC connected to an AC system
By M. Durrant; H. Werner; K. Abbott [View]
[Download]

Abstract: The power and line voltage of an AC system connected to a VSC HVDC transmission system are demonstrated to be static non-linear functions of the states of the VSC under certain simpli¯cations. A power and voltage control system is tuned using a linearised model and tested on a PSCAD model. Satisfactory results were obtained for systems with SCR greater than 4.0, but results deteriorate for lower values of SCR.

   A discrete sliding mode control of a three-phase active filter
By J. Matas; L. G. de Vicuña; J. Miret; J. M. Guerrero; J. Majó [View]
[Download]

Abstract: This paper proposes the design of a discrete sliding control of a three-phase active filter based on feedback linearization techniques. The active filter is controlled through two control loops. The inner control loop is regulated by a discrete sliding mode control in order to achieve the active wave-shaping function of the active filter. The outer voltage loop regulates the average voltage on the dc bus capacitor. The discrete sliding control surfaces are designed by imposing a desired dynamic behavior on the system, which allows us to determine the main parameters of the sliding mode controller. This procedure leads to discrete-time switching surfaces, which provides robustness with regard to external disturbances, and a good dynamic response of the filter.

   Sliding mode fuzzy logic control technique for induction motor drive system
By A. Kaletsanos; F. Xepapas; S. Xepapas; S.N. Manias [View]
[Download]

Abstract: This paper presents a novel control method for Induction motor drives. A voltage source Inverter feeds the machine. The variables, mechanical rotational speed, electro-mechanical torque and rotor flux linkage are directly controlled. The control principle is based on a sliding mode nonlinear technique combined with fuzzy logic methodology. The proposed controllers for direct torque and rotor flux control construct an intelligent and robust drive system. The IM drive performance was tested and simulation and experimental results are presented.

   Direct adaptive fuzzy control for an induction motor drive
By M. R. Chekkouri; J. M. Moreno; A. Arias; L. Romeral [View]
[Download]

Abstract: In this paper an adaptive control speed for an induction motor drive is presented. The proposed adaptive scheme uses a Mamdani fuzzy controller. The parameters of the membership output function characterizing the linguistic terms in the fuzzy If-Then rules change according the adaptation. The adaptive law is developed for the purpose of tracking a reference speed. Based on the Lyapunov theory, the stability of the whole system and the convergence of the tracking error are also discussed. Computer simulations show that the effect of both the fuzzy approximations error and the external disturbance on the tracking error can be attenuated by the proposed controller.

   Robust control of a PMSM with adaptive cancellation of channel interaction
By P.-O. Nyman; W. Sulkowski [View]
[Download]

Abstract: Current control of permanent magnet synchronous motor is designed for optimal robust performance under both uncertainties in stator parameters and variation of operating speed. To avoid the conservatism inherent in many robust control approaches, and to admit a exible choice of optimization criteria, the design is carried out with help of a genetic algorithm. The controller is composed of two SISO PI-controllers and a static feedback decoupling network that minimizes the interaction between the d- and q-axes uniformly across the parameter uncertainty range, and across the speed range. Remaining interaction is eliminated by a simple on-line adaptive cancellation. This results in a practically perfect decoupling in the stationary case, and better than a guaranteed worst performance under all circumstances.

EPE 2003 - Topic 05a: Optimal Control, Robust Control, Non-Linear Control
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2003 - Conference > EPE 2003 - Topic 05: APPLICATION OF CONTROL METHODS TO ELECTRICAL SYSTEMS > EPE 2003 - Topic 05a: Optimal Control, Robust Control, Non-Linear Control
	[return to parent folder]

	Active vibration suppression using DTC drive and automatic parameter identification of two mass system By H. Sarén; O. Pyrhönen	[View] [Download]
Abstract: In this paper active mechanical vibration suppression has been investigated in DTC synchronous motor drive. Phenomena in two mass system with flexible shaft was studied. A simple method to identify parameters for mechanical two mass system is presented. State feedback based optimal speed control was tested.

	Robust speed control of a low damped electromechanical system: application to a four masses experimental test bench By S. Poullain; J. Sabatier; P. Latteux; J-L. Thomas; A. Oustaloup	[View] [Download]
Abstract: Robust speed control of a low damped electromechanical system with backlash is studied, when the controlled load angular speed can not be measured. The proposed control strategy combines a Luenberger observer (load angular speed and load torque disturbance estimations) and a robust CRONE controller. The proposed control strategy is applied to a four mass experimental test bench.

	CPWL approximation for solar panel control By Y. Labit; G. Garcia; C. Alonso	[View] [Download]
Abstract: This communication deals with the control of a solar panel approximated by canonical piecewise linear modelling (CPWLM). The proposed approach consists on the panel modelling by a set of uncertain linear models via a piecewise linear model. The global law is designed by scheduled local robust control laws taking into account some performances.

	Widening the stability range of a PWM inverter using a nonparametric chaos control By B. Robert; H.H.C. Iu; M. Feki	[View] [Download]
Abstract: Out of their usual operating zones, many static converters can exhibit undesirable aperiodic behaviours. Sometimes chaotic and strange attractors appear and must be avoided by an appropriate control. Usual correctors fail to stabilize unstable periodic orbits (UPOs) embedded in the chaotic zones. Specific methods must be used in order to control chaos. However, most of them need a precise knowledge of the model in order to investigate the nonlinear dynamics. Thus, they are not robust because of their dependence on the parameters of the model. In this paper, a simple corrector is improved to stabilize the fundamental periodic operating mode by using a robust model free chaos control. The converter under control is a current programmed inverter driven by a low frequency reference. The stability range is approximately doubled and the sampled current error is reduced.

	GPC robustification by the Youla parameter - Application to position control of an induction motor By P. Rodríguez; D. Dumur; E. Mendes	[View] [Download]
Abstract: This paper presents a two-steps design procedure for Generalized Predictive Control (GPC) controllers, and the experimental results obtained with this algorithm applied to the position control of an induction motor. In the first step of the design procedure, an initial GPC controller is required to ensure the desired input/output tracking behaviour. This initial controller is then robustified considering temporal and frequency constraints, which are formulated by means of the Youla parametrization within a convex optimisation framework. The optimal Youla parameter is finally obtained by solving this optimisation problem. The Youla parametrization permits closed loop convex specifications, and the two-degrees of freedom GPC controller allows to robustify the initial controller without changes in the input/output behaviour. Moreover, a compromise between robustness and closed loop behaviour, like disturbance rejection, can be easily managed. An application to the position control of an induction motor drive is presented, where the robustness of the initial GPC controller regarding model uncertainties in high frequency is enhanced while respecting a temporal template for the disturbance rejection. The results are finally compared to those obtained with an anticipative PID controller.

	Robust control via H2/Hinfinity approach applied to an induction motor By S. Cauet; L. Rambault	[View] [Download]
Abstract: This paper deals with a robust H2/Hinfinity technique applied to an induction motor. In order to robustify a linearizing decoupled feedback against parametric variations, H2/Hinfinity controllers with a reference model are added. The main interests are performances and real decoupling between the rotor flux and the speed. Real time implementation are carried out.

	Tailoring ripple and spectrum of chaotic DC-DC converters By J. Weber; O. Woywode; H. Gueldner	[View] [Download]
Abstract: Chaotic dc-dc converter operation—associated with a broad (non-peaky) spectrum—was suggested to reduce the electromagnetic interference of a switched mode power supply. Chaotic operation is, on the other hand, accompanied by a large ripple. The paper discusses methods (implemented into the inner current loop) that allow for tailoring ripple and spectrum. The methods are verified by simulation and experiment. The voltage feedback loop is closed around the inner current loop. The response of the converter to a step load change under chaotic and periodic operation is compared.

	Speed controller for drives with critical torsional conditions By K. Schiftner	[View] [Download]
Abstract: The paper presents a speed controller for torsionally stressed drives. The significant feature of the system is the suppression of the torsional vibrations as well as its robustness with respect to indeterminate system parameters and modelling errors. The theoretical approach is verified herein in various drives for high-inertia output load.

	Robust sensorless induction motor control for electric propulsion ship By F. Terrien; S. Siala	[View] [Download]
Abstract: This paper deals with robust sensorless induction motor control applied to electrical ship propulsion. The control fulfils the marine process specificities and constraints. The flux estimation is based on a two step adaptative Kalman Filter (KF). A fourth order KF estimates the flux and the currents, then the rotational speed is estimated by integration of a non-linear equation of estimated flux and current errors. RST regulators are used rather than the classical PI to improve the robustness/performances compromise.

	Near-time-optimal position control of electrical drives with permanent magnet synchronous motor By J. Vittek; T. Baculák; S.J. Dodds; R. Perryman	[View] [Download]
Abstract: The paper presents a ‘near-time-optimal’ (NTO) position control strategy for electrical drives with permanent magnet synchronous motors, where the responses to changes in the demanded position of the driven mechanism should ideally take place in minimum time. The principles of time-optimal-control and forced dynamic control are combined to form a novel method of achieving a nearly time optimal position control performance in drives equipped with controllers enabling close following of time varying reference position inputs. The position response of a real-time model of the closed-loop time optimal control system provides the reference input to the drive control loop. Experimental results show good correspondence with theoretical predictions and confirm the near time optimal control.

	A simple approach to improve sliding mode control in induction motor drives By W. Jamal; M. S. Khanniche; P. A. Mawby	[View] [Download]
Abstract: In the past, Variable Structure Control with Sliding Mode (VSC-SLM) has been successfully applied to versatile control applications, in which robustness against parametric variations and external disturbances are guaranteed. Therefore, it is usefully employed in systems with uncertain and time-varying parameters such as the induction motor (IM) drive. However, with the heritage of past control experience, the chattering effects about the sliding surface remains a major concern and as a result it has limited its practical application in high performance drive systems. This paper presents a method to introduce fuzzy logic algorithms into the design of VSC-SLM, in order to alleviate the chattering problems and to improve the dynamics of the IM drive. The theoretical bases for this algorithm are given, and a concrete scheme for constructing the proposed control system is presented. A computer model for the proposed controller is constructed and simulated when it is applied to the outer loop speed control of an IM drive. The proposed method has achieved a considerable improvement of the drive dynamics in contrast to those obtained with the conventional VSC-SLM.

	Robust speed control of PMSM servodrive based on ANN application By T. Pajchrowski; K. Urbanski; K. Zawirski	[View] [Download]
Abstract: In the paper an application of artificial neural network to design a robust control of PMSM servodrive speed was presented. Proper training of ANN ensures a control robust against variation of moment of inertia. Simulation and laboratory results proved good robustness of the system.

	Hybrid theory based model predictive control of electrical drives with friction By I. Petroviæ; M. Baotiæ; L. Matiæ; N. Periæ	[View] [Download]
Abstract: In this paper hybrid theory has been applied to design a state-feedback control law of an electrical drive with friction. The drive is modeled as a piecewise affine (PWA) system and a finite time optimal control problem is formulated for such a hybrid system. Three most often used friction models are considered and compared based on their suitability for the PWA description. It is shown that a resetintegrator friction model gives a PWA model of smaller complexity than LuGre and Karnopp friction models. A state-feedback optimal control law in a form of a look-up table is then derived via dynamic programming. The control system behavior is tested by computer simulations. The results indicate that the proposed control strategy is a valuable alternative to the currently used control strategies.

	A comparison of controller designs for VSC-HVDC By M. Durrant; H. Werner; K. Abbott	[View] [Download]
Abstract: The VSC current controllers of a VSC HVDC transmission system are designed on a 2 state linear VSC model using IMC and LQR design methods. The controller performance on the linear model, a more complex analytical model including PLL and AC ¯lter dynamics, and a rigorous PSCAD model is compared. The increasing discrepancy between the two state model and the other models as SCR is reduced is explained and the e®ects on control performance are demonstrated.

	A robust fuzzy-sliding mode position controller for motor drives systems with flexible shafts By J. Arellano-Padilla; G.M. Asher; M. Sumner	[View] [Download]
Abstract: This paper reviews and develops a new approach to Fuzzy-Sliding Mode Control (FSMC) for the robust position control of practical motor drive systems operating with elastic transmissions and loads with variable mechanical parameters. Robustness is achieved through the definition of a real time reference transient trajectory eS for the switching function of the Sliding Mode Control (SMC). The integration value of eS is the input for a fuzzy interpolation between control laws corresponding to the boundary values of the plant parameters variations. The paper reviews the background of the approach and develops a formal design procedure for the fuzzy interpolation to yield robust performance for large range of plant parameter variations. Experimental results are presented.

	Control design for VSC HVDC connected to an AC system By M. Durrant; H. Werner; K. Abbott	[View] [Download]
Abstract: The power and line voltage of an AC system connected to a VSC HVDC transmission system are demonstrated to be static non-linear functions of the states of the VSC under certain simpli¯cations. A power and voltage control system is tuned using a linearised model and tested on a PSCAD model. Satisfactory results were obtained for systems with SCR greater than 4.0, but results deteriorate for lower values of SCR.

	A discrete sliding mode control of a three-phase active filter By J. Matas; L. G. de Vicuña; J. Miret; J. M. Guerrero; J. Majó	[View] [Download]
Abstract: This paper proposes the design of a discrete sliding control of a three-phase active filter based on feedback linearization techniques. The active filter is controlled through two control loops. The inner control loop is regulated by a discrete sliding mode control in order to achieve the active wave-shaping function of the active filter. The outer voltage loop regulates the average voltage on the dc bus capacitor. The discrete sliding control surfaces are designed by imposing a desired dynamic behavior on the system, which allows us to determine the main parameters of the sliding mode controller. This procedure leads to discrete-time switching surfaces, which provides robustness with regard to external disturbances, and a good dynamic response of the filter.

	Sliding mode fuzzy logic control technique for induction motor drive system By A. Kaletsanos; F. Xepapas; S. Xepapas; S.N. Manias	[View] [Download]
Abstract: This paper presents a novel control method for Induction motor drives. A voltage source Inverter feeds the machine. The variables, mechanical rotational speed, electro-mechanical torque and rotor flux linkage are directly controlled. The control principle is based on a sliding mode nonlinear technique combined with fuzzy logic methodology. The proposed controllers for direct torque and rotor flux control construct an intelligent and robust drive system. The IM drive performance was tested and simulation and experimental results are presented.

	Direct adaptive fuzzy control for an induction motor drive By M. R. Chekkouri; J. M. Moreno; A. Arias; L. Romeral	[View] [Download]
Abstract: In this paper an adaptive control speed for an induction motor drive is presented. The proposed adaptive scheme uses a Mamdani fuzzy controller. The parameters of the membership output function characterizing the linguistic terms in the fuzzy If-Then rules change according the adaptation. The adaptive law is developed for the purpose of tracking a reference speed. Based on the Lyapunov theory, the stability of the whole system and the convergence of the tracking error are also discussed. Computer simulations show that the effect of both the fuzzy approximations error and the external disturbance on the tracking error can be attenuated by the proposed controller.

	Robust control of a PMSM with adaptive cancellation of channel interaction By P.-O. Nyman; W. Sulkowski	[View] [Download]
Abstract: Current control of permanent magnet synchronous motor is designed for optimal robust performance under both uncertainties in stator parameters and variation of operating speed. To avoid the conservatism inherent in many robust control approaches, and to admit a exible choice of optimization criteria, the design is carried out with help of a genetic algorithm. The controller is composed of two SISO PI-controllers and a static feedback decoupling network that minimizes the interaction between the d- and q-axes uniformly across the parameter uncertainty range, and across the speed range. Remaining interaction is eliminated by a simple on-line adaptive cancellation. This results in a practically perfect decoupling in the stationary case, and better than a guaranteed worst performance under all circumstances.