Permanent magnet generator with non-regular armed stator

A valve for gas cylinder, said valve comprising:

• a body with an inlet, an outlet and a passage interconnecting the inlet and outlet;
• a flow control device mounted on the body and controlling the flow of gas in the passage;
• an electric generator with a turbine wheel located in the passage, configured for outputting electric power when the gas flow in the passage rotates the turbine wheel, wherein the electric generator comprises:
• a rotor with permanent magnets, configured for rotating about a rotation axis;
• a stator comprising at least one magnetic yoke with arms extending one of axially inside and axially outside of the rotor so as to be adjacent to one of a radial inner side and a radial outer side, respectively, of the rotor;
• wherein the arms of the at least one magnetic yoke are circumferentially distributed so as to form a slot between each pair of adjacent arms, each slot and each arm showing a width;
• wherein the widths of the arms have different values distributed along the circumference;
• and
• wherein each arm extends angularly over a sector
• θ
• i
• =
• 〈
• θ
• 〉
• 2
• +
• i
• .
• d
• ⁢
• θ
• where i is an integer comprised between 1 and N;
• N being the number of arms and (θ) being an average sector angle of the N arms.

A conduit with a wall delimiting a passage for a fluid and with an electric generator with a turbine wheel located in the passage so as to be driven when the fluid flows, wherein the generator comprises:

• a rotor with permanent magnets, configured for rotating about a rotation axis;
• a stator comprising at least one magnetic yoke with arms extending one of axially inside and axially outside of the rotor so as to be adjacent to one of a radial inner side and a radial outer side, respectively, of the rotor;
• wherein the arms of the at least one magnetic yoke are circumferentially distributed so as to form a slot between each pair of adjacent arms, each slot and each arm showing a width;
• wherein the widths of the arms have different values distributed along the circumference;
• and
• wherein each arm extends angularly over a sector
• θ
• i
• =
• 〈
• θ
• 〉
• 2
• +
• i
• .
• d
• ⁢
• θ
• where i is an integer comprised between 1 and N;
• N being the number of arms and) (θ) being an average sector angle of the N arms.

A method for dimensioning an electric generator, said method comprising:

• a rotor with permanent magnets configured for rotating about a rotation axis;
• a stator comprising at least one magnetic yoke with arms extending one of axially inside and axially outside of the rotor so as to be adjacent to one of a radial inner side and a radial outer side, respectively, of the rotor;
• and
• wherein the arms are circumferentially distributed so as to form a slot between each pair of adjacent arms, each slot and each arm showing a width;
• and
• comprising the step of:
• dimensioning the widths of the arms with different values distributed along the circumference so as to lower a cogging torque on the rotor, wherein each arm extends angularly over a sector
• θ
• i
• =
• 〈
• θ
• 〉
• 2
• +
• i
• .
• d
• ⁢
• θ
• where i is an integer comprised between 1 and N;
• N being the number of arms and (θ) being an average sector angle of the N arms.