Experimental nonlinear torque control of a permanent-magnet synchronous motor using saliency
Résumé
In this paper, a new nonlinear control strategy is proposed for a permanent-magnet salient-pole synchronous motor. This control strategy simultaneously achieves accurate torque control and copper losses minimization without recurring to an internal current loop nor to any feedforward compensation. It takes advantage of the rotor saliency by allowing the current (id) to have nonzero values. This, in turn, allows us to increase the power factor of the machine and to raise the maximum admissible torque. We apply input-output linearization techniques where the inputs are the stator voltages and the outputs are the torque and a judiciously chosen new output. This new output insures a well-defined relative degree and is linked to the copper losses in such a way that, when forced to zero, it leads to maximum machine efficiency. The performance of our nonlinear controller is demonstrated by a real-time implementation using a digital signal processor (DSP) chip on a permanent-magnet salient-pole synchronous motor with sinusoidal flux distribution. The results are compared to the ones obtained with a scheme which forces the id current to zero
Mots clés
Copper
Digital signal processing chips
Digital signal processors
Linearization techniques
Reactive power
Rotors
Stators
Synchronous motors
Torque control
Voltage
compensation
digital control
feedforward
linearisation techniques
losses
machine control
magnetic flux
minimisation
nonlinear control systems
permanent magnet motors
power factor
copper losses minimization
digital signal processor chip
feedforward compensation
input-output linearization techniques
internal current loop
maximum machine efficiency
nonlinear controller
nonlinear torque control
permanent-magnet synchronous motor
rotor saliency
saliency
sinusoidal flux distribution
stator voltages