A control method for verifying the compatibility between an input filter and a variable speed drive. The method includes applying a plurality of successive commands so as to define a plurality of operating points of the electric motor, for each operating point, measuring the DC voltage of the bus, comparing the maximum variation in the amplitude of the DC voltage measured for the operating point with a threshold value, defining a new operating point as long as the maximum variation in the amplitude of the DC voltage is lower than the threshold value, determining an operating range including all of the operating points for which the maximum variation in the amplitude of the DC voltage is lower than the threshold value.