Patent ID: 6847183

Claim:
An electronic power supply device for a low noise synchronous motor including a permanent-magnet rotor and a stator with at least two pairs of stator poles and corresponding windings, comprising: a power input receiving directly a main voltage supply; a signal input connected to a position sensor for detecting the position and polarity of the rotor; a capacitor serially connected to one winding of only one pair to act as a 90° phase shifter; a static switch driven by an output of said electronic power device and connected to drive another winding of said two pairs; and a further signal input for receiving a measure of the current flowing through said static switch to allow driving said static switch only when necessary, wherein said static switch is driven according to a function of the angular position of the rotor, according to the values of the main power supply voltages and to a value of said current flowing in said static switch.