Abstract: A vector control system for a squirrel-cage asynchronous motor powered by a width-modulated pulse generator, the system including a device for evaluating the modulus and the phase of at least one of the fluxes in the motor relative to a fixed frame of reference, and a device for evaluating first in-phase and quadrature components, relative to the flux of at least one of the currents supplied to the motor. The system also includes means a device for determining second in-phase and quadrature components relative to the flux in the motor, defining a control voltage as a function at least of the first components and of a requested torque value, together with means a device for converting the second components into a corresponding polar representation having a modulus and an argument, for the purpose of controlling the pulse generator.