order to limit the voltage Vdc(t) of the DC-link capacitor 11 during regeneration mode, for example caused by braking or by an external sudden decrease of the load torque. 

Firstly, the control method performs the step of determining the instantaneous active currents ia(t) and iaref(t) based on: the duty cycles Ud(t), Uq(t), the available currents id(t), iq(t) and the current references idref, iqref (block 100) (using the axis d and q of the Park transformation matrices). 

Preferably, the control method determines the instantaneous active currents ia(t) and iaref(t) by the formulas: 

Equation (l2a) 

It is understood that the active current can be computed alternatively resorting to currents and duty cycles in a reference frame different from the synchronous one, for instance using quantities expressed in the synchronous reference frame - β , when available. 

Equation (l2b) 

Moreover, the control method performs the step of determining a worst-case active current iaws(t) (block 110), by computing the minimum between the active currents ia(t) and iaref(t) determined by Equation (12): 

Equation (13) 

The method further performs the step of determining two maximum absolute correction signals idmax(t) and iqmax(t) (block 120), using the value iaref(t) computed by Equation (l2a) : 

